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<div class="yui-g" id="topics-i18n-translation">
<div class="section" id="s-module-django.utils.translation">
<span id="s-translation"></span><span id="module-django.utils.translation"></span><span id="translation"></span><h1>Translation<a class="headerlink" href="#module-django.utils.translation" title="Permalink to this headline">¶</a></h1>
<div class="section" id="s-overview">
<span id="overview"></span><h2>Overview<a class="headerlink" href="#overview" title="Permalink to this headline">¶</a></h2>
<p>In order to make a Django project translatable, you have to add a minimal amount
of hooks to your Python code and templates. These hooks are called
<a class="reference internal" href="index.html#term-translation-string"><em class="xref std std-term">translation strings</em></a>. They tell Django: “This text
should be translated into the end user’s language, if a translation for this
text is available in that language.” It’s your responsibility to mark
translatable strings; the system can only translate strings it knows about.</p>
<p>Django then provides utilities to extract the translation strings into a
<a class="reference internal" href="index.html#term-message-file"><em class="xref std std-term">message file</em></a>. This file is a convenient way for translators to provide
the equivalent of the translation strings in the target language. Once the
translators have filled in the message file, it must be compiled. This process
relies on the GNU gettext toolset.</p>
<p>Once this is done, Django takes care of translating Web apps on the fly in each
available language, according to users’ language preferences.</p>
<p>Django’s internationalization hooks are on by default, and that means there’s a
bit of i18n-related overhead in certain places of the framework. If you don’t
use internationalization, you should take the two seconds to set
<a class="reference internal" href="../../ref/settings.html#std:setting-USE_I18N"><tt class="xref std std-setting docutils literal"><span class="pre">USE_I18N</span> <span class="pre">=</span> <span class="pre">False</span></tt></a> in your settings file. Then Django will
make some optimizations so as not to load the internationalization machinery.
You’ll probably also want to remove <tt class="docutils literal"><span class="pre">'django.core.context_processors.i18n'</span></tt>
from your <a class="reference internal" href="../../ref/settings.html#std:setting-TEMPLATE_CONTEXT_PROCESSORS"><tt class="xref std std-setting docutils literal"><span class="pre">TEMPLATE_CONTEXT_PROCESSORS</span></tt></a> setting.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">There is also an independent but related <a class="reference internal" href="../../ref/settings.html#std:setting-USE_L10N"><tt class="xref std std-setting docutils literal"><span class="pre">USE_L10N</span></tt></a> setting that
controls if Django should implement format localization. See
<a class="reference internal" href="formatting.html"><em>Format localization</em></a> for more details.</p>
</div>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">Make sure you’ve activated translation for your project (the fastest way is
to check if <a class="reference internal" href="../../ref/settings.html#std:setting-MIDDLEWARE_CLASSES"><tt class="xref std std-setting docutils literal"><span class="pre">MIDDLEWARE_CLASSES</span></tt></a> includes
<a class="reference internal" href="../../ref/middleware.html#django.middleware.locale.LocaleMiddleware" title="django.middleware.locale.LocaleMiddleware"><tt class="xref py py-mod docutils literal"><span class="pre">django.middleware.locale.LocaleMiddleware</span></tt></a>). If you haven’t yet,
see <a class="reference internal" href="#how-django-discovers-language-preference"><em>How Django discovers language preference</em></a>.</p>
</div>
</div>
<div class="section" id="s-internationalization-in-python-code">
<span id="internationalization-in-python-code"></span><h2>Internationalization: in Python code<a class="headerlink" href="#internationalization-in-python-code" title="Permalink to this headline">¶</a></h2>
<div class="section" id="s-standard-translation">
<span id="standard-translation"></span><h3>Standard translation<a class="headerlink" href="#standard-translation" title="Permalink to this headline">¶</a></h3>
<p>Specify a translation string by using the function
<a class="reference internal" href="../../ref/utils.html#django.utils.translation.ugettext" title="django.utils.translation.ugettext"><tt class="xref py py-func docutils literal"><span class="pre">ugettext()</span></tt></a>. It’s convention to import this
as a shorter alias, <tt class="docutils literal"><span class="pre">_</span></tt>, to save typing.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p>Python’s standard library <tt class="docutils literal"><span class="pre">gettext</span></tt> module installs <tt class="docutils literal"><span class="pre">_()</span></tt> into the
global namespace, as an alias for <tt class="docutils literal"><span class="pre">gettext()</span></tt>. In Django, we have chosen
not to follow this practice, for a couple of reasons:</p>
<ol class="last arabic simple">
<li>For international character set (Unicode) support,
<a class="reference internal" href="../../ref/utils.html#django.utils.translation.ugettext" title="django.utils.translation.ugettext"><tt class="xref py py-func docutils literal"><span class="pre">ugettext()</span></tt></a> is more useful than
<tt class="docutils literal"><span class="pre">gettext()</span></tt>. Sometimes, you should be using
<a class="reference internal" href="../../ref/utils.html#django.utils.translation.ugettext_lazy" title="django.utils.translation.ugettext_lazy"><tt class="xref py py-func docutils literal"><span class="pre">ugettext_lazy()</span></tt></a> as the default
translation method for a particular file. Without <tt class="docutils literal"><span class="pre">_()</span></tt> in the
global namespace, the developer has to think about which is the
most appropriate translation function.</li>
<li>The underscore character (<tt class="docutils literal"><span class="pre">_</span></tt>) is used to represent “the previous
result” in Python’s interactive shell and doctest tests. Installing a
global <tt class="docutils literal"><span class="pre">_()</span></tt> function causes interference. Explicitly importing
<tt class="docutils literal"><span class="pre">ugettext()</span></tt> as <tt class="docutils literal"><span class="pre">_()</span></tt> avoids this problem.</li>
</ol>
</div>
<p>In this example, the text <tt class="docutils literal"><span class="pre">"Welcome</span> <span class="pre">to</span> <span class="pre">my</span> <span class="pre">site."</span></tt> is marked as a translation
string:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">ugettext</span> <span class="k">as</span> <span class="n">_</span>
<span class="k">def</span> <span class="nf">my_view</span><span class="p">(</span><span class="n">request</span><span class="p">):</span>
<span class="n">output</span> <span class="o">=</span> <span class="n">_</span><span class="p">(</span><span class="s">"Welcome to my site."</span><span class="p">)</span>
<span class="k">return</span> <span class="n">HttpResponse</span><span class="p">(</span><span class="n">output</span><span class="p">)</span>
</pre></div>
</div>
<p>Obviously, you could code this without using the alias. This example is
identical to the previous one:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">ugettext</span>
<span class="k">def</span> <span class="nf">my_view</span><span class="p">(</span><span class="n">request</span><span class="p">):</span>
<span class="n">output</span> <span class="o">=</span> <span class="n">ugettext</span><span class="p">(</span><span class="s">"Welcome to my site."</span><span class="p">)</span>
<span class="k">return</span> <span class="n">HttpResponse</span><span class="p">(</span><span class="n">output</span><span class="p">)</span>
</pre></div>
</div>
<p>Translation works on computed values. This example is identical to the previous
two:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">def</span> <span class="nf">my_view</span><span class="p">(</span><span class="n">request</span><span class="p">):</span>
<span class="n">words</span> <span class="o">=</span> <span class="p">[</span><span class="s">'Welcome'</span><span class="p">,</span> <span class="s">'to'</span><span class="p">,</span> <span class="s">'my'</span><span class="p">,</span> <span class="s">'site.'</span><span class="p">]</span>
<span class="n">output</span> <span class="o">=</span> <span class="n">_</span><span class="p">(</span><span class="s">' '</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">words</span><span class="p">))</span>
<span class="k">return</span> <span class="n">HttpResponse</span><span class="p">(</span><span class="n">output</span><span class="p">)</span>
</pre></div>
</div>
<p>Translation works on variables. Again, here’s an identical example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">def</span> <span class="nf">my_view</span><span class="p">(</span><span class="n">request</span><span class="p">):</span>
<span class="n">sentence</span> <span class="o">=</span> <span class="s">'Welcome to my site.'</span>
<span class="n">output</span> <span class="o">=</span> <span class="n">_</span><span class="p">(</span><span class="n">sentence</span><span class="p">)</span>
<span class="k">return</span> <span class="n">HttpResponse</span><span class="p">(</span><span class="n">output</span><span class="p">)</span>
</pre></div>
</div>
<p>(The caveat with using variables or computed values, as in the previous two
examples, is that Django’s translation-string-detecting utility,
<a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">makemessages</span></tt></a>, won’t be able to find
these strings. More on <a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">makemessages</span></tt></a> later.)</p>
<p>The strings you pass to <tt class="docutils literal"><span class="pre">_()</span></tt> or <tt class="docutils literal"><span class="pre">ugettext()</span></tt> can take placeholders,
specified with Python’s standard named-string interpolation syntax. Example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">def</span> <span class="nf">my_view</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="n">m</span><span class="p">,</span> <span class="n">d</span><span class="p">):</span>
<span class="n">output</span> <span class="o">=</span> <span class="n">_</span><span class="p">(</span><span class="s">'Today is </span><span class="si">%(month)s</span><span class="s"> </span><span class="si">%(day)s</span><span class="s">.'</span><span class="p">)</span> <span class="o">%</span> <span class="p">{</span><span class="s">'month'</span><span class="p">:</span> <span class="n">m</span><span class="p">,</span> <span class="s">'day'</span><span class="p">:</span> <span class="n">d</span><span class="p">}</span>
<span class="k">return</span> <span class="n">HttpResponse</span><span class="p">(</span><span class="n">output</span><span class="p">)</span>
</pre></div>
</div>
<p>This technique lets language-specific translations reorder the placeholder
text. For example, an English translation may be <tt class="docutils literal"><span class="pre">"Today</span> <span class="pre">is</span> <span class="pre">November</span> <span class="pre">26."</span></tt>,
while a Spanish translation may be <tt class="docutils literal"><span class="pre">"Hoy</span> <span class="pre">es</span> <span class="pre">26</span> <span class="pre">de</span> <span class="pre">Noviembre."</span></tt> – with the
the month and the day placeholders swapped.</p>
<p>For this reason, you should use named-string interpolation (e.g., <tt class="docutils literal"><span class="pre">%(day)s</span></tt>)
instead of positional interpolation (e.g., <tt class="docutils literal"><span class="pre">%s</span></tt> or <tt class="docutils literal"><span class="pre">%d</span></tt>) whenever you
have more than a single parameter. If you used positional interpolation,
translations wouldn’t be able to reorder placeholder text.</p>
</div>
<div class="section" id="s-comments-for-translators">
<span id="s-translator-comments"></span><span id="comments-for-translators"></span><span id="translator-comments"></span><h3>Comments for translators<a class="headerlink" href="#comments-for-translators" title="Permalink to this headline">¶</a></h3>
<div class="versionadded">
<span class="title">New in Django 1.3:</span> <a class="reference internal" href="../../releases/1.3.html"><em>Please see the release notes</em></a></div>
<p>If you would like to give translators hints about a translatable string, you
can add a comment prefixed with the <tt class="docutils literal"><span class="pre">Translators</span></tt> keyword on the line
preceding the string, e.g.:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">def</span> <span class="nf">my_view</span><span class="p">(</span><span class="n">request</span><span class="p">):</span>
<span class="c"># Translators: This message appears on the home page only</span>
<span class="n">output</span> <span class="o">=</span> <span class="n">ugettext</span><span class="p">(</span><span class="s">"Welcome to my site."</span><span class="p">)</span>
</pre></div>
</div>
<p>This also works in templates with the <a class="reference internal" href="../../ref/templates/builtins.html#std:templatetag-comment"><tt class="xref std std-ttag docutils literal"><span class="pre">comment</span></tt></a> tag:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">comment</span> <span class="cp">%}</span><span class="c">Translators: This is a text of the base template </span><span class="cp">{%</span> <span class="k">endcomment</span> <span class="cp">%}</span>
</pre></div>
</div>
<p>The comment will then appear in the resulting <tt class="docutils literal"><span class="pre">.po</span></tt> file and should also be
displayed by most translation tools.</p>
</div>
<div class="section" id="s-marking-strings-as-no-op">
<span id="marking-strings-as-no-op"></span><h3>Marking strings as no-op<a class="headerlink" href="#marking-strings-as-no-op" title="Permalink to this headline">¶</a></h3>
<p>Use the function <a class="reference internal" href="../../ref/utils.html#django.utils.translation.ugettext_noop" title="django.utils.translation.ugettext_noop"><tt class="xref py py-func docutils literal"><span class="pre">django.utils.translation.ugettext_noop()</span></tt></a> to mark a
string as a translation string without translating it. The string is later
translated from a variable.</p>
<p>Use this if you have constant strings that should be stored in the source
language because they are exchanged over systems or users – such as strings
in a database – but should be translated at the last possible point in time,
such as when the string is presented to the user.</p>
</div>
<div class="section" id="s-pluralization">
<span id="pluralization"></span><h3>Pluralization<a class="headerlink" href="#pluralization" title="Permalink to this headline">¶</a></h3>
<p>Use the function <a class="reference internal" href="../../ref/utils.html#django.utils.translation.ungettext" title="django.utils.translation.ungettext"><tt class="xref py py-func docutils literal"><span class="pre">django.utils.translation.ungettext()</span></tt></a> to specify
pluralized messages.</p>
<p><tt class="docutils literal"><span class="pre">ungettext</span></tt> takes three arguments: the singular translation string, the plural
translation string and the number of objects.</p>
<p>This function is useful when you need your Django application to be localizable
to languages where the number and complexity of <a class="reference external" href="http://www.gnu.org/software/gettext/manual/gettext.html#Plural-forms">plural forms</a> is
greater than the two forms used in English (‘object’ for the singular and
‘objects’ for all the cases where <tt class="docutils literal"><span class="pre">count</span></tt> is different from one, irrespective
of its value.)</p>
<p>For example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">ungettext</span>
<span class="k">def</span> <span class="nf">hello_world</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="n">count</span><span class="p">):</span>
<span class="n">page</span> <span class="o">=</span> <span class="n">ungettext</span><span class="p">(</span>
<span class="s">'there is </span><span class="si">%(count)d</span><span class="s"> object'</span><span class="p">,</span>
<span class="s">'there are </span><span class="si">%(count)d</span><span class="s"> objects'</span><span class="p">,</span>
<span class="n">count</span><span class="p">)</span> <span class="o">%</span> <span class="p">{</span>
<span class="s">'count'</span><span class="p">:</span> <span class="n">count</span><span class="p">,</span>
<span class="p">}</span>
<span class="k">return</span> <span class="n">HttpResponse</span><span class="p">(</span><span class="n">page</span><span class="p">)</span>
</pre></div>
</div>
<p>In this example the number of objects is passed to the translation
languages as the <tt class="docutils literal"><span class="pre">count</span></tt> variable.</p>
<p>Lets see a slightly more complex usage example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">ungettext</span>
<span class="n">count</span> <span class="o">=</span> <span class="n">Report</span><span class="o">.</span><span class="n">objects</span><span class="o">.</span><span class="n">count</span><span class="p">()</span>
<span class="k">if</span> <span class="n">count</span> <span class="o">==</span> <span class="mi">1</span><span class="p">:</span>
<span class="n">name</span> <span class="o">=</span> <span class="n">Report</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">verbose_name</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">name</span> <span class="o">=</span> <span class="n">Report</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">verbose_name_plural</span>
<span class="n">text</span> <span class="o">=</span> <span class="n">ungettext</span><span class="p">(</span>
<span class="s">'There is </span><span class="si">%(count)d</span><span class="s"> </span><span class="si">%(name)s</span><span class="s"> available.'</span><span class="p">,</span>
<span class="s">'There are </span><span class="si">%(count)d</span><span class="s"> </span><span class="si">%(name)s</span><span class="s"> available.'</span><span class="p">,</span>
<span class="n">count</span>
<span class="p">)</span> <span class="o">%</span> <span class="p">{</span>
<span class="s">'count'</span><span class="p">:</span> <span class="n">count</span><span class="p">,</span>
<span class="s">'name'</span><span class="p">:</span> <span class="n">name</span>
<span class="p">}</span>
</pre></div>
</div>
<p>Here we reuse localizable, hopefully already translated literals (contained in
the <tt class="docutils literal"><span class="pre">verbose_name</span></tt> and <tt class="docutils literal"><span class="pre">verbose_name_plural</span></tt> model <tt class="docutils literal"><span class="pre">Meta</span></tt> options) for
other parts of the sentence so all of it is consistently based on the
cardinality of the elements at play.</p>
<div class="admonition note" id="pluralization-var-notes">
<p class="first admonition-title">Note</p>
<p>When using this technique, make sure you use a single name for every
extrapolated variable included in the literal. In the example above note how
we used the <tt class="docutils literal"><span class="pre">name</span></tt> Python variable in both translation strings. This
example would fail:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">ungettext</span>
<span class="kn">from</span> <span class="nn">myapp.models</span> <span class="kn">import</span> <span class="n">Report</span>
<span class="n">count</span> <span class="o">=</span> <span class="n">Report</span><span class="o">.</span><span class="n">objects</span><span class="o">.</span><span class="n">count</span><span class="p">()</span>
<span class="n">d</span> <span class="o">=</span> <span class="p">{</span>
<span class="s">'count'</span><span class="p">:</span> <span class="n">count</span><span class="p">,</span>
<span class="s">'name'</span><span class="p">:</span> <span class="n">Report</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">verbose_name</span><span class="p">,</span>
<span class="s">'plural_name'</span><span class="p">:</span> <span class="n">Report</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">verbose_name_plural</span>
<span class="p">}</span>
<span class="n">text</span> <span class="o">=</span> <span class="n">ungettext</span><span class="p">(</span>
<span class="s">'There is </span><span class="si">%(count)d</span><span class="s"> </span><span class="si">%(name)s</span><span class="s"> available.'</span><span class="p">,</span>
<span class="s">'There are </span><span class="si">%(count)d</span><span class="s"> </span><span class="si">%(plural_name)s</span><span class="s"> available.'</span><span class="p">,</span>
<span class="n">count</span>
<span class="p">)</span> <span class="o">%</span> <span class="n">d</span>
</pre></div>
</div>
<p>You would get an error when running <a class="reference internal" href="../../ref/django-admin.html#django-admin-compilemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span>
<span class="pre">compilemessages</span></tt></a>:</p>
<div class="last highlight-python"><pre>a format specification for argument 'name', as in 'msgstr[0]', doesn't exist in 'msgid'</pre>
</div>
</div>
</div>
<div class="section" id="s-contextual-markers">
<span id="s-id1"></span><span id="contextual-markers"></span><span id="id1"></span><h3>Contextual markers<a class="headerlink" href="#contextual-markers" title="Permalink to this headline">¶</a></h3>
<div class="versionadded">
<span class="title">New in Django 1.3:</span> <a class="reference internal" href="../../releases/1.3.html"><em>Please see the release notes</em></a></div>
<p>Sometimes words have several meanings, such as <tt class="docutils literal"><span class="pre">"May"</span></tt> in English, which
refers to a month name and to a verb. To enable translators to translate
these words correctly in different contexts, you can use the
<a class="reference internal" href="../../ref/utils.html#django.utils.translation.pgettext" title="django.utils.translation.pgettext"><tt class="xref py py-func docutils literal"><span class="pre">django.utils.translation.pgettext()</span></tt></a> function, or the
<a class="reference internal" href="../../ref/utils.html#django.utils.translation.npgettext" title="django.utils.translation.npgettext"><tt class="xref py py-func docutils literal"><span class="pre">django.utils.translation.npgettext()</span></tt></a> function if the string needs
pluralization. Both take a context string as the first variable.</p>
<p>In the resulting <tt class="docutils literal"><span class="pre">.po</span></tt> file, the string will then appear as often as there are
different contextual markers for the same string (the context will appear on the
<tt class="docutils literal"><span class="pre">msgctxt</span></tt> line), allowing the translator to give a different translation for
each of them.</p>
<p>For example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">pgettext</span>
<span class="n">month</span> <span class="o">=</span> <span class="n">pgettext</span><span class="p">(</span><span class="s">"month name"</span><span class="p">,</span> <span class="s">"May"</span><span class="p">)</span>
</pre></div>
</div>
<p>or:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">pgettext_lazy</span>
<span class="k">class</span> <span class="nc">MyThing</span><span class="p">(</span><span class="n">models</span><span class="o">.</span><span class="n">Model</span><span class="p">):</span>
<span class="n">name</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">CharField</span><span class="p">(</span><span class="n">help_text</span><span class="o">=</span><span class="n">pgettext_lazy</span><span class="p">(</span>
<span class="s">'help text for MyThing model'</span><span class="p">,</span> <span class="s">'This is the help text'</span><span class="p">))</span>
</pre></div>
</div>
<p>will appear in the <tt class="docutils literal"><span class="pre">.po</span></tt> file as:</p>
<div class="highlight-po"><pre>msgctxt "month name"
msgid "May"
msgstr ""</pre>
</div>
<div class="versionadded">
<span class="title">New in Django 1.4:</span> <a class="reference internal" href="../../releases/1.4.html"><em>Please see the release notes</em></a></div>
<p>Contextual markers are also supported by the <a class="reference internal" href="#std:templatetag-trans"><tt class="xref std std-ttag docutils literal"><span class="pre">trans</span></tt></a> and
<a class="reference internal" href="#std:templatetag-blocktrans"><tt class="xref std std-ttag docutils literal"><span class="pre">blocktrans</span></tt></a> template tags.</p>
</div>
<div class="section" id="s-lazy-translation">
<span id="s-lazy-translations"></span><span id="lazy-translation"></span><span id="lazy-translations"></span><h3>Lazy translation<a class="headerlink" href="#lazy-translation" title="Permalink to this headline">¶</a></h3>
<p>Use the lazy versions of translation functions in
<a class="reference internal" href="#module-django.utils.translation" title="django.utils.translation"><tt class="xref py py-mod docutils literal"><span class="pre">django.utils.translation</span></tt></a> (easily recognizable by the <tt class="docutils literal"><span class="pre">lazy</span></tt> suffix in
their names) to translate strings lazily – when the value is accessed rather
than when they’re called.</p>
<p>These functions store a lazy reference to the string – not the actual
translation. The translation itself will be done when the string is used in a
string context, such as in template rendering.</p>
<p>This is essential when calls to these functions are located in code paths that
are executed at module load time.</p>
<p>This is something that can easily happen when defining models, forms and
model forms, because Django implements these such that their fields are
actually class-level attributes. For that reason, make sure to use lazy
translations in the following cases:</p>
<div class="section" id="s-model-fields-and-relationships-verbose-name-and-help-text-option-values">
<span id="model-fields-and-relationships-verbose-name-and-help-text-option-values"></span><h4>Model fields and relationships <tt class="docutils literal"><span class="pre">verbose_name</span></tt> and <tt class="docutils literal"><span class="pre">help_text</span></tt> option values<a class="headerlink" href="#model-fields-and-relationships-verbose-name-and-help-text-option-values" title="Permalink to this headline">¶</a></h4>
<p>For example, to translate the help text of the <em>name</em> field in the following
model, do the following:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">ugettext_lazy</span>
<span class="k">class</span> <span class="nc">MyThing</span><span class="p">(</span><span class="n">models</span><span class="o">.</span><span class="n">Model</span><span class="p">):</span>
<span class="n">name</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">CharField</span><span class="p">(</span><span class="n">help_text</span><span class="o">=</span><span class="n">ugettext_lazy</span><span class="p">(</span><span class="s">'This is the help text'</span><span class="p">))</span>
</pre></div>
</div>
<p>You can mark names of <tt class="docutils literal"><span class="pre">ForeignKey</span></tt>, <tt class="docutils literal"><span class="pre">ManyTomanyField</span></tt> or <tt class="docutils literal"><span class="pre">OneToOneField</span></tt>
relationship as translatable by using their <tt class="docutils literal"><span class="pre">verbose_name</span></tt> options:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">ugettext_lazy</span> <span class="k">as</span> <span class="n">_</span>
<span class="k">class</span> <span class="nc">MyThing</span><span class="p">(</span><span class="n">models</span><span class="o">.</span><span class="n">Model</span><span class="p">):</span>
<span class="n">kind</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">ForeignKey</span><span class="p">(</span><span class="n">ThingKind</span><span class="p">,</span> <span class="n">related_name</span><span class="o">=</span><span class="s">'kinds'</span><span class="p">,</span>
<span class="n">verbose_name</span><span class="o">=</span><span class="n">_</span><span class="p">(</span><span class="s">'kind'</span><span class="p">))</span>
</pre></div>
</div>
<p>Just like you would do in <a class="reference internal" href="../../ref/models/options.html#django.db.models.Options.verbose_name" title="django.db.models.Options.verbose_name"><tt class="xref py py-attr docutils literal"><span class="pre">verbose_name</span></tt></a> you
should provide a lowercase verbose name text for the relation as Django will
automatically titlecase it when required.</p>
</div>
<div class="section" id="s-model-verbose-names-values">
<span id="model-verbose-names-values"></span><h4>Model verbose names values<a class="headerlink" href="#model-verbose-names-values" title="Permalink to this headline">¶</a></h4>
<p>It is recommended to always provide explicit
<a class="reference internal" href="../../ref/models/options.html#django.db.models.Options.verbose_name" title="django.db.models.Options.verbose_name"><tt class="xref py py-attr docutils literal"><span class="pre">verbose_name</span></tt></a> and
<a class="reference internal" href="../../ref/models/options.html#django.db.models.Options.verbose_name_plural" title="django.db.models.Options.verbose_name_plural"><tt class="xref py py-attr docutils literal"><span class="pre">verbose_name_plural</span></tt></a> options rather than
relying on the fallback English-centric and somewhat naïve determination of
verbose names Django performs bu looking at the model’s class name:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">ugettext_lazy</span>
<span class="k">class</span> <span class="nc">MyThing</span><span class="p">(</span><span class="n">models</span><span class="o">.</span><span class="n">Model</span><span class="p">):</span>
<span class="n">name</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">CharField</span><span class="p">(</span><span class="n">_</span><span class="p">(</span><span class="s">'name'</span><span class="p">),</span> <span class="n">help_text</span><span class="o">=</span><span class="n">ugettext_lazy</span><span class="p">(</span><span class="s">'This is the help text'</span><span class="p">))</span>
<span class="k">class</span> <span class="nc">Meta</span><span class="p">:</span>
<span class="n">verbose_name</span> <span class="o">=</span> <span class="n">ugettext_lazy</span><span class="p">(</span><span class="s">'my thing'</span><span class="p">)</span>
<span class="n">verbose_name_plural</span> <span class="o">=</span> <span class="n">ugettext_lazy</span><span class="p">(</span><span class="s">'my things'</span><span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="s-model-methods-short-description-attribute-values">
<span id="model-methods-short-description-attribute-values"></span><h4>Model methods <tt class="docutils literal"><span class="pre">short_description</span></tt> attribute values<a class="headerlink" href="#model-methods-short-description-attribute-values" title="Permalink to this headline">¶</a></h4>
<p>For model methods, you can provide translations to Django and the admin site
with the <tt class="docutils literal"><span class="pre">short_description</span></tt> attribute:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">ugettext_lazy</span> <span class="k">as</span> <span class="n">_</span>
<span class="k">class</span> <span class="nc">MyThing</span><span class="p">(</span><span class="n">models</span><span class="o">.</span><span class="n">Model</span><span class="p">):</span>
<span class="n">kind</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">ForeignKey</span><span class="p">(</span><span class="n">ThingKind</span><span class="p">,</span> <span class="n">related_name</span><span class="o">=</span><span class="s">'kinds'</span><span class="p">,</span>
<span class="n">verbose_name</span><span class="o">=</span><span class="n">_</span><span class="p">(</span><span class="s">'kind'</span><span class="p">))</span>
<span class="k">def</span> <span class="nf">is_mouse</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">kind</span><span class="o">.</span><span class="n">type</span> <span class="o">==</span> <span class="n">MOUSE_TYPE</span>
<span class="n">is_mouse</span><span class="o">.</span><span class="n">short_description</span> <span class="o">=</span> <span class="n">_</span><span class="p">(</span><span class="s">'Is it a mouse?'</span><span class="p">)</span>
</pre></div>
</div>
</div>
</div>
<div class="section" id="s-working-with-lazy-translation-objects">
<span id="working-with-lazy-translation-objects"></span><h3>Working with lazy translation objects<a class="headerlink" href="#working-with-lazy-translation-objects" title="Permalink to this headline">¶</a></h3>
<p>The result of a <tt class="docutils literal"><span class="pre">ugettext_lazy()</span></tt> call can be used wherever you would use a
unicode string (an object with type <tt class="docutils literal"><span class="pre">unicode</span></tt>) in Python. If you try to use
it where a bytestring (a <tt class="docutils literal"><span class="pre">str</span></tt> object) is expected, things will not work as
expected, since a <tt class="docutils literal"><span class="pre">ugettext_lazy()</span></tt> object doesn’t know how to convert
itself to a bytestring. You can’t use a unicode string inside a bytestring,
either, so this is consistent with normal Python behavior. For example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="c"># This is fine: putting a unicode proxy into a unicode string.</span>
<span class="s">u"Hello </span><span class="si">%s</span><span class="s">"</span> <span class="o">%</span> <span class="n">ugettext_lazy</span><span class="p">(</span><span class="s">"people"</span><span class="p">)</span>
<span class="c"># This will not work, since you cannot insert a unicode object</span>
<span class="c"># into a bytestring (nor can you insert our unicode proxy there)</span>
<span class="s">"Hello </span><span class="si">%s</span><span class="s">"</span> <span class="o">%</span> <span class="n">ugettext_lazy</span><span class="p">(</span><span class="s">"people"</span><span class="p">)</span>
</pre></div>
</div>
<p>If you ever see output that looks like <tt class="docutils literal"><span class="pre">"hello</span>
<span class="pre"><django.utils.functional...>"</span></tt>, you have tried to insert the result of
<tt class="docutils literal"><span class="pre">ugettext_lazy()</span></tt> into a bytestring. That’s a bug in your code.</p>
<p>If you don’t like the long <tt class="docutils literal"><span class="pre">ugettext_lazy</span></tt> name, you can just alias it as
<tt class="docutils literal"><span class="pre">_</span></tt> (underscore), like so:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">ugettext_lazy</span> <span class="k">as</span> <span class="n">_</span>
<span class="k">class</span> <span class="nc">MyThing</span><span class="p">(</span><span class="n">models</span><span class="o">.</span><span class="n">Model</span><span class="p">):</span>
<span class="n">name</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">CharField</span><span class="p">(</span><span class="n">help_text</span><span class="o">=</span><span class="n">_</span><span class="p">(</span><span class="s">'This is the help text'</span><span class="p">))</span>
</pre></div>
</div>
<p>Using <tt class="docutils literal"><span class="pre">ugettext_lazy()</span></tt> and <tt class="docutils literal"><span class="pre">ungettext_lazy()</span></tt> to mark strings in models
and utility functions is a common operation. When you’re working with these
objects elsewhere in your code, you should ensure that you don’t accidentally
convert them to strings, because they should be converted as late as possible
(so that the correct locale is in effect). This necessitates the use of the
helper function described next.</p>
<div class="section" id="s-joining-strings-string-concat">
<span id="joining-strings-string-concat"></span><h4>Joining strings: string_concat()<a class="headerlink" href="#joining-strings-string-concat" title="Permalink to this headline">¶</a></h4>
<p>Standard Python string joins (<tt class="docutils literal"><span class="pre">''.join([...])</span></tt>) will not work on lists
containing lazy translation objects. Instead, you can use
<a class="reference internal" href="../../ref/utils.html#django.utils.translation.string_concat" title="django.utils.translation.string_concat"><tt class="xref py py-func docutils literal"><span class="pre">django.utils.translation.string_concat()</span></tt></a>, which creates a lazy object
that concatenates its contents <em>and</em> converts them to strings only when the
result is included in a string. For example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">string_concat</span>
<span class="o">...</span>
<span class="n">name</span> <span class="o">=</span> <span class="n">ugettext_lazy</span><span class="p">(</span><span class="s">u'John Lennon'</span><span class="p">)</span>
<span class="n">instrument</span> <span class="o">=</span> <span class="n">ugettext_lazy</span><span class="p">(</span><span class="s">u'guitar'</span><span class="p">)</span>
<span class="n">result</span> <span class="o">=</span> <span class="n">string_concat</span><span class="p">(</span><span class="n">name</span><span class="p">,</span> <span class="s">': '</span><span class="p">,</span> <span class="n">instrument</span><span class="p">)</span>
</pre></div>
</div>
<p>In this case, the lazy translations in <tt class="docutils literal"><span class="pre">result</span></tt> will only be converted to
strings when <tt class="docutils literal"><span class="pre">result</span></tt> itself is used in a string (usually at template
rendering time).</p>
</div>
</div>
<div class="section" id="s-localized-names-of-languages">
<span id="localized-names-of-languages"></span><h3>Localized names of languages<a class="headerlink" href="#localized-names-of-languages" title="Permalink to this headline">¶</a></h3>
<dl class="function">
<dt id="django.utils.translation.get_language_info">
<tt class="descname">get_language_info</tt>()<a class="headerlink" href="#django.utils.translation.get_language_info" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<div class="versionadded">
<span class="title">New in Django 1.3:</span> <a class="reference internal" href="../../releases/1.3.html"><em>Please see the release notes</em></a></div>
<p>The <tt class="docutils literal"><span class="pre">get_language_info()</span></tt> function provides detailed information about
languages:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">get_language_info</span>
<span class="gp">>>> </span><span class="n">li</span> <span class="o">=</span> <span class="n">get_language_info</span><span class="p">(</span><span class="s">'de'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">print</span> <span class="n">li</span><span class="p">[</span><span class="s">'name'</span><span class="p">],</span> <span class="n">li</span><span class="p">[</span><span class="s">'name_local'</span><span class="p">],</span> <span class="n">li</span><span class="p">[</span><span class="s">'bidi'</span><span class="p">]</span>
<span class="go">German Deutsch False</span>
</pre></div>
</div>
<p>The <tt class="docutils literal"><span class="pre">name</span></tt> and <tt class="docutils literal"><span class="pre">name_local</span></tt> attributes of the dictionary contain the name of
the language in English and in the language itself, respectively. The <tt class="docutils literal"><span class="pre">bidi</span></tt>
attribute is True only for bi-directional languages.</p>
<p>The source of the language information is the <tt class="docutils literal"><span class="pre">django.conf.locale</span></tt> module.
Similar access to this information is available for template code. See below.</p>
</div>
</div>
<div class="section" id="s-internationalization-in-template-code">
<span id="s-specifying-translation-strings-in-template-code"></span><span id="internationalization-in-template-code"></span><span id="specifying-translation-strings-in-template-code"></span><h2>Internationalization: in template code<a class="headerlink" href="#internationalization-in-template-code" title="Permalink to this headline">¶</a></h2>
<p>Translations in <a class="reference internal" href="../templates.html"><em>Django templates</em></a> uses two template
tags and a slightly different syntax than in Python code. To give your template
access to these tags, put <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">load</span> <span class="pre">i18n</span> <span class="pre">%}</span></tt> toward the top of your template.
As with all template tags, this tag needs to be loaded in all templates which
use translations, even those templates that extend from other templates which
have already loaded the <tt class="docutils literal"><span class="pre">i18n</span></tt> tag.</p>
<div class="section" id="s-trans-template-tag">
<span id="s-std:templatetag-trans"></span><span id="trans-template-tag"></span><span id="std:templatetag-trans"></span><h3><tt class="docutils literal"><span class="pre">trans</span></tt> template tag<a class="headerlink" href="#trans-template-tag" title="Permalink to this headline">¶</a></h3>
<p>The <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">trans</span> <span class="pre">%}</span></tt> template tag translates either a constant string
(enclosed in single or double quotes) or variable content:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="nt"><title></span><span class="cp">{%</span> <span class="k">trans</span> <span class="s2">"This is the title."</span> <span class="cp">%}</span><span class="nt"></title></span>
<span class="nt"><title></span><span class="cp">{%</span> <span class="k">trans</span> <span class="nv">myvar</span> <span class="cp">%}</span><span class="nt"></title></span>
</pre></div>
</div>
<p>If the <tt class="docutils literal"><span class="pre">noop</span></tt> option is present, variable lookup still takes place but the
translation is skipped. This is useful when “stubbing out” content that will
require translation in the future:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="nt"><title></span><span class="cp">{%</span> <span class="k">trans</span> <span class="s2">"myvar"</span> <span class="nv">noop</span> <span class="cp">%}</span><span class="nt"></title></span>
</pre></div>
</div>
<p>Internally, inline translations use an
<a class="reference internal" href="../../ref/utils.html#django.utils.translation.ugettext" title="django.utils.translation.ugettext"><tt class="xref py py-func docutils literal"><span class="pre">ugettext()</span></tt></a> call.</p>
<p>In case a template var (<tt class="docutils literal"><span class="pre">myvar</span></tt> above) is passed to the tag, the tag will
first resolve such variable to a string at run-time and then look up that
string in the message catalogs.</p>
<p>It’s not possible to mix a template variable inside a string within <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">trans</span>
<span class="pre">%}</span></tt>. If your translations require strings with variables (placeholders), use
<tt class="docutils literal"><span class="pre">{%</span> <span class="pre">blocktrans</span> <span class="pre">%}</span></tt> instead.</p>
<div class="versionadded">
<span class="title">New in Django 1.4:</span> <a class="reference internal" href="../../releases/1.4.html"><em>Please see the release notes</em></a></div>
<p>If you’d like to retrieve a translated string without displaying it, you can
use the following syntax:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">trans</span> <span class="s2">"This is the title"</span> <span class="k">as</span> <span class="nv">the_title</span> <span class="cp">%}</span>
<span class="nt"><title></span><span class="cp">{{</span> <span class="nv">the_title</span> <span class="cp">}}</span><span class="nt"></title></span>
<span class="nt"><meta</span> <span class="na">name=</span><span class="s">"description"</span> <span class="na">content=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">the_title</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span>
</pre></div>
</div>
<p>In practice you’ll use this to get strings that are used in multiple places
or should be used as arguments for other template tags or filters:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">trans</span> <span class="s2">"starting point"</span> <span class="k">as</span> <span class="nv">start</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">trans</span> <span class="s2">"end point"</span> <span class="k">as</span> <span class="nv">end</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">trans</span> <span class="s2">"La Grande Boucle"</span> <span class="k">as</span> <span class="nv">race</span> <span class="cp">%}</span>
<span class="nt"><h1></span>
<span class="nt"><a</span> <span class="na">href=</span><span class="s">"/"</span> <span class="na">title=</span><span class="s">"</span><span class="cp">{%</span> <span class="k">blocktrans</span> <span class="cp">%}</span><span class="s">Back to '</span><span class="cp">{{</span> <span class="nv">race</span> <span class="cp">}}</span><span class="s">' homepage</span><span class="cp">{%</span> <span class="k">endblocktrans</span> <span class="cp">%}</span><span class="s">"</span><span class="nt">></span><span class="cp">{{</span> <span class="nv">race</span> <span class="cp">}}</span><span class="nt"></a></span>
<span class="nt"></h1></span>
<span class="nt"><p></span>
<span class="cp">{%</span> <span class="k">for</span> <span class="nv">stage</span> <span class="k">in</span> <span class="nv">tour_stages</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">cycle</span> <span class="nv">start</span> <span class="nv">end</span> <span class="cp">%}</span>: <span class="cp">{{</span> <span class="nv">stage</span> <span class="cp">}}{%</span> <span class="k">if</span> <span class="nb">forloop</span><span class="nv">.counter</span><span class="o">|</span><span class="nf">divisibleby</span><span class="o">:</span><span class="m">2</span> <span class="cp">%}</span><span class="nt"><br</span> <span class="nt">/></span><span class="cp">{%</span> <span class="k">else</span> <span class="cp">%}</span>, <span class="cp">{%</span> <span class="k">endif</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span>
<span class="nt"></p></span>
</pre></div>
</div>
<div class="versionadded">
<span class="title">New in Django 1.4:</span> <a class="reference internal" href="../../releases/1.4.html"><em>Please see the release notes</em></a></div>
<p><tt class="docutils literal"><span class="pre">{%</span> <span class="pre">trans</span> <span class="pre">%}</span></tt> also supports <a class="reference internal" href="#contextual-markers"><em>contextual markers</em></a>
using the <tt class="docutils literal"><span class="pre">context</span></tt> keyword:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">trans</span> <span class="s2">"May"</span> <span class="nv">context</span> <span class="s2">"month name"</span> <span class="cp">%}</span>
</pre></div>
</div>
</div>
<div class="section" id="s-blocktrans-template-tag">
<span id="s-std:templatetag-blocktrans"></span><span id="blocktrans-template-tag"></span><span id="std:templatetag-blocktrans"></span><h3><tt class="docutils literal"><span class="pre">blocktrans</span></tt> template tag<a class="headerlink" href="#blocktrans-template-tag" title="Permalink to this headline">¶</a></h3>
<div class="versionchanged">
<span class="title">Changed in Django 1.3:</span> New keyword argument format.</div>
<p>Contrarily to the <a class="reference internal" href="#std:templatetag-trans"><tt class="xref std std-ttag docutils literal"><span class="pre">trans</span></tt></a> tag, the <tt class="docutils literal"><span class="pre">blocktrans</span></tt> tag allows you to mark
complex sentences consisting of literals and variable content for translation
by making use of placeholders:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">blocktrans</span> <span class="cp">%}</span>This string will have <span class="cp">{{</span> <span class="nv">value</span> <span class="cp">}}</span> inside.<span class="cp">{%</span> <span class="k">endblocktrans</span> <span class="cp">%}</span>
</pre></div>
</div>
<p>To translate a template expression – say, accessing object attributes or
using template filters – you need to bind the expression to a local variable
for use within the translation block. Examples:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">blocktrans</span> <span class="k">with</span> <span class="nv">amount</span><span class="o">=</span><span class="nv">article.price</span> <span class="cp">%}</span>
That will cost $ <span class="cp">{{</span> <span class="nv">amount</span> <span class="cp">}}</span>.
<span class="cp">{%</span> <span class="k">endblocktrans</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">blocktrans</span> <span class="k">with</span> <span class="nv">myvar</span><span class="o">=</span><span class="nv">value</span><span class="o">|</span><span class="nf">filter</span> <span class="cp">%}</span>
This will have <span class="cp">{{</span> <span class="nv">myvar</span> <span class="cp">}}</span> inside.
<span class="cp">{%</span> <span class="k">endblocktrans</span> <span class="cp">%}</span>
</pre></div>
</div>
<p>You can use multiple expressions inside a single <tt class="docutils literal"><span class="pre">blocktrans</span></tt> tag:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">blocktrans</span> <span class="k">with</span> <span class="nv">book_t</span><span class="o">=</span><span class="nv">book</span><span class="o">|</span><span class="nf">title</span> <span class="nv">author_t</span><span class="o">=</span><span class="nv">author</span><span class="o">|</span><span class="nf">title</span> <span class="cp">%}</span>
This is <span class="cp">{{</span> <span class="nv">book_t</span> <span class="cp">}}</span> by <span class="cp">{{</span> <span class="nv">author_t</span> <span class="cp">}}</span>
<span class="cp">{%</span> <span class="k">endblocktrans</span> <span class="cp">%}</span>
</pre></div>
</div>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The previous more verbose format is still supported:
<tt class="docutils literal"><span class="pre">{%</span> <span class="pre">blocktrans</span> <span class="pre">with</span> <span class="pre">book|title</span> <span class="pre">as</span> <span class="pre">book_t</span> <span class="pre">and</span> <span class="pre">author|title</span> <span class="pre">as</span> <span class="pre">author_t</span> <span class="pre">%}</span></tt></p>
</div>
<div class="versionchanged">
<span class="title">Changed in Django 1.4:</span> <a class="reference internal" href="../../releases/1.4.html"><em>Please see the release notes</em></a></div>
<p>If resolving one of the block arguments fails, blocktrans will fall back to
the default language by deactivating the currently active language
temporarily with the <a class="reference internal" href="../../ref/utils.html#django.utils.translation.deactivate_all" title="django.utils.translation.deactivate_all"><tt class="xref py py-func docutils literal"><span class="pre">deactivate_all()</span></tt></a>
function.</p>
<p>This tag also provides for pluralization. To use it:</p>
<ul class="simple">
<li>Designate and bind a counter value with the name <tt class="docutils literal"><span class="pre">count</span></tt>. This value will
be the one used to select the right plural form.</li>
<li>Specify both the singular and plural forms separating them with the
<tt class="docutils literal"><span class="pre">{%</span> <span class="pre">plural</span> <span class="pre">%}</span></tt> tag within the <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">blocktrans</span> <span class="pre">%}</span></tt> and
<tt class="docutils literal"><span class="pre">{%</span> <span class="pre">endblocktrans</span> <span class="pre">%}</span></tt> tags.</li>
</ul>
<p>An example:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">blocktrans</span> <span class="nv">count</span> <span class="nv">counter</span><span class="o">=</span><span class="nv">list</span><span class="o">|</span><span class="nf">length</span> <span class="cp">%}</span>
There is only one <span class="cp">{{</span> <span class="nv">name</span> <span class="cp">}}</span> object.
<span class="cp">{%</span> <span class="k">plural</span> <span class="cp">%}</span>
There are <span class="cp">{{</span> <span class="nv">counter</span> <span class="cp">}}</span> <span class="cp">{{</span> <span class="nv">name</span> <span class="cp">}}</span> objects.
<span class="cp">{%</span> <span class="k">endblocktrans</span> <span class="cp">%}</span>
</pre></div>
</div>
<p>A more complex example:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">blocktrans</span> <span class="k">with</span> <span class="nv">amount</span><span class="o">=</span><span class="nv">article.price</span> <span class="nv">count</span> <span class="nv">years</span><span class="o">=</span><span class="nv">i.length</span> <span class="cp">%}</span>
That will cost $ <span class="cp">{{</span> <span class="nv">amount</span> <span class="cp">}}</span> per year.
<span class="cp">{%</span> <span class="k">plural</span> <span class="cp">%}</span>
That will cost $ <span class="cp">{{</span> <span class="nv">amount</span> <span class="cp">}}</span> per <span class="cp">{{</span> <span class="nv">years</span> <span class="cp">}}</span> years.
<span class="cp">{%</span> <span class="k">endblocktrans</span> <span class="cp">%}</span>
</pre></div>
</div>
<p>When you use both the pluralization feature and bind values to local variables
in addition to the counter value, keep in mind that the <tt class="docutils literal"><span class="pre">blocktrans</span></tt>
construct is internally converted to an <tt class="docutils literal"><span class="pre">ungettext</span></tt> call. This means the
same <a class="reference internal" href="#pluralization-var-notes"><em>notes regarding ungettext variables</em></a>
apply.</p>
<p>Reverse URL lookups cannot be carried out within the <tt class="docutils literal"><span class="pre">blocktrans</span></tt> and should
be retrieved (and stored) beforehand:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">url</span> <span class="nv">path.to.view</span> <span class="nv">arg</span> <span class="nv">arg2</span> <span class="k">as</span> <span class="nv">the_url</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">blocktrans</span> <span class="cp">%}</span>
This is a URL: <span class="cp">{{</span> <span class="nv">the_url</span> <span class="cp">}}</span>
<span class="cp">{%</span> <span class="k">endblocktrans</span> <span class="cp">%}</span>
</pre></div>
</div>
<div class="versionadded">
<span class="title">New in Django 1.4:</span> <a class="reference internal" href="../../releases/1.4.html"><em>Please see the release notes</em></a></div>
<p><tt class="docutils literal"><span class="pre">{%</span> <span class="pre">blocktrans</span> <span class="pre">%}</span></tt> also supports <a class="reference internal" href="#contextual-markers"><em>contextual
markers</em></a> using the <tt class="docutils literal"><span class="pre">context</span></tt> keyword:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">blocktrans</span> <span class="k">with</span> <span class="nv">name</span><span class="o">=</span><span class="nv">user.username</span> <span class="nv">context</span> <span class="s2">"greeting"</span> <span class="cp">%}</span>Hi <span class="cp">{{</span> <span class="nv">name</span> <span class="cp">}}{%</span> <span class="k">endblocktrans</span> <span class="cp">%}</span>
</pre></div>
</div>
</div>
<div class="section" id="s-other-tags">
<span id="s-template-translation-vars"></span><span id="other-tags"></span><span id="template-translation-vars"></span><h3>Other tags<a class="headerlink" href="#other-tags" title="Permalink to this headline">¶</a></h3>
<p>Each <tt class="docutils literal"><span class="pre">RequestContext</span></tt> has access to three translation-specific variables:</p>
<ul class="simple">
<li><tt class="docutils literal"><span class="pre">LANGUAGES</span></tt> is a list of tuples in which the first element is the
<a class="reference internal" href="index.html#term-language-code"><em class="xref std std-term">language code</em></a> and the second is the language name (translated into
the currently active locale).</li>
<li><tt class="docutils literal"><span class="pre">LANGUAGE_CODE</span></tt> is the current user’s preferred language, as a string.
Example: <tt class="docutils literal"><span class="pre">en-us</span></tt>. (See <a class="reference internal" href="#how-django-discovers-language-preference"><em>How Django discovers language preference</em></a>.)</li>
<li><tt class="docutils literal"><span class="pre">LANGUAGE_BIDI</span></tt> is the current locale’s direction. If True, it’s a
right-to-left language, e.g.: Hebrew, Arabic. If False it’s a
left-to-right language, e.g.: English, French, German etc.</li>
</ul>
<p>If you don’t use the <tt class="docutils literal"><span class="pre">RequestContext</span></tt> extension, you can get those values with
three tags:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">get_current_language</span> <span class="k">as</span> <span class="nv">LANGUAGE_CODE</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">get_available_languages</span> <span class="k">as</span> <span class="nv">LANGUAGES</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">get_current_language_bidi</span> <span class="k">as</span> <span class="nv">LANGUAGE_BIDI</span> <span class="cp">%}</span>
</pre></div>
</div>
<p>These tags also require a <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">load</span> <span class="pre">i18n</span> <span class="pre">%}</span></tt>.</p>
<p>Translation hooks are also available within any template block tag that accepts
constant strings. In those cases, just use <tt class="docutils literal"><span class="pre">_()</span></tt> syntax to specify a
translation string:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">some_special_tag</span> <span class="kp">_</span><span class="o">(</span><span class="s2">"Page not found"</span><span class="o">)</span> <span class="nv">value</span><span class="o">|</span><span class="nf">yesno</span><span class="o">:</span><span class="kp">_</span><span class="o">(</span><span class="s2">"yes,no"</span><span class="o">)</span> <span class="cp">%}</span>
</pre></div>
</div>
<p>In this case, both the tag and the filter will see the already-translated
string, so they don’t need to be aware of translations.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">In this example, the translation infrastructure will be passed the string
<tt class="docutils literal"><span class="pre">"yes,no"</span></tt>, not the individual strings <tt class="docutils literal"><span class="pre">"yes"</span></tt> and <tt class="docutils literal"><span class="pre">"no"</span></tt>. The
translated string will need to contain the comma so that the filter
parsing code knows how to split up the arguments. For example, a German
translator might translate the string <tt class="docutils literal"><span class="pre">"yes,no"</span></tt> as <tt class="docutils literal"><span class="pre">"ja,nein"</span></tt>
(keeping the comma intact).</p>
</div>
<div class="versionadded">
<span class="title">New in Django 1.3:</span> <a class="reference internal" href="../../releases/1.3.html"><em>Please see the release notes</em></a></div>
<p>You can also retrieve information about any of the available languages using
provided template tags and filters. To get information about a single language,
use the <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">get_language_info</span> <span class="pre">%}</span></tt> tag:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">get_language_info</span> <span class="nv">for</span> <span class="nv">LANGUAGE_CODE</span> <span class="k">as</span> <span class="nv">lang</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">get_language_info</span> <span class="nv">for</span> <span class="s2">"pl"</span> <span class="k">as</span> <span class="nv">lang</span> <span class="cp">%}</span>
</pre></div>
</div>
<p>You can then access the information:</p>
<div class="highlight-html+django"><div class="highlight"><pre>Language code: <span class="cp">{{</span> <span class="nv">lang.code</span> <span class="cp">}}</span><span class="nt"><br</span> <span class="nt">/></span>
Name of language: <span class="cp">{{</span> <span class="nv">lang.name_local</span> <span class="cp">}}</span><span class="nt"><br</span> <span class="nt">/></span>
Name in English: <span class="cp">{{</span> <span class="nv">lang.name</span> <span class="cp">}}</span><span class="nt"><br</span> <span class="nt">/></span>
Bi-directional: <span class="cp">{{</span> <span class="nv">lang.bidi</span> <span class="cp">}}</span>
</pre></div>
</div>
<p>You can also use the <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">get_language_info_list</span> <span class="pre">%}</span></tt> template tag to retrieve
information for a list of languages (e.g. active languages as specified in
<a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGES"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGES</span></tt></a>). See <a class="reference internal" href="#set-language-redirect-view"><em>the section about the set_language redirect
view</em></a> for an example of how to display a language
selector using <tt class="docutils literal"><span class="pre">{%</span> <span class="pre">get_language_info_list</span> <span class="pre">%}</span></tt>.</p>
<p>In addition to <a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGES"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGES</span></tt></a> style nested tuples,
<tt class="docutils literal"><span class="pre">{%</span> <span class="pre">get_language_info_list</span> <span class="pre">%}</span></tt> supports simple lists of language codes.
If you do this in your view:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">return</span> <span class="n">render_to_response</span><span class="p">(</span><span class="s">'mytemplate.html'</span><span class="p">,</span> <span class="p">{</span>
<span class="s">'available_languages'</span><span class="p">:</span> <span class="p">[</span><span class="s">'en'</span><span class="p">,</span> <span class="s">'es'</span><span class="p">,</span> <span class="s">'fr'</span><span class="p">],</span>
<span class="p">},</span> <span class="n">RequestContext</span><span class="p">(</span><span class="n">request</span><span class="p">))</span>
</pre></div>
</div>
<p>you can iterate over those languages in the template:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">get_language_info_list</span> <span class="nv">for</span> <span class="nv">available_languages</span> <span class="k">as</span> <span class="nv">langs</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">for</span> <span class="nv">lang</span> <span class="k">in</span> <span class="nv">langs</span> <span class="cp">%}</span> ... <span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span>
</pre></div>
</div>
<p>There are also simple filters available for convenience:</p>
<ul class="simple">
<li><tt class="docutils literal"><span class="pre">{{</span> <span class="pre">LANGUAGE_CODE|language_name</span> <span class="pre">}}</span></tt> (“German”)</li>
<li><tt class="docutils literal"><span class="pre">{{</span> <span class="pre">LANGUAGE_CODE|language_name_local</span> <span class="pre">}}</span></tt> (“Deutsch”)</li>
<li><tt class="docutils literal"><span class="pre">{{</span> <span class="pre">LANGUAGE_CODE|bidi</span> <span class="pre">}}</span></tt> (False)</li>
</ul>
</div>
</div>
<div class="section" id="s-internationalization-in-javascript-code">
<span id="internationalization-in-javascript-code"></span><h2>Internationalization: in JavaScript code<a class="headerlink" href="#internationalization-in-javascript-code" title="Permalink to this headline">¶</a></h2>
<p>Adding translations to JavaScript poses some problems:</p>
<ul class="simple">
<li>JavaScript code doesn’t have access to a <tt class="docutils literal"><span class="pre">gettext</span></tt> implementation.</li>
<li>JavaScript code doesn’t have access to <tt class="docutils literal"><span class="pre">.po</span></tt> or <tt class="docutils literal"><span class="pre">.mo</span></tt> files; they need to
be delivered by the server.</li>
<li>The translation catalogs for JavaScript should be kept as small as
possible.</li>
</ul>
<p>Django provides an integrated solution for these problems: It passes the
translations into JavaScript, so you can call <tt class="docutils literal"><span class="pre">gettext</span></tt>, etc., from within
JavaScript.</p>
<div class="section" id="s-module-django.views.i18n">
<span id="s-the-javascript-catalog-view"></span><span id="s-javascript-catalog-view"></span><span id="module-django.views.i18n"></span><span id="the-javascript-catalog-view"></span><span id="javascript-catalog-view"></span><h3>The <tt class="docutils literal"><span class="pre">javascript_catalog</span></tt> view<a class="headerlink" href="#module-django.views.i18n" title="Permalink to this headline">¶</a></h3>
<dl class="function">
<dt id="django.views.i18n.javascript_catalog">
<tt class="descname">javascript_catalog</tt>(<em>request</em>, <em>domain='djangojs'</em>, <em>packages=None</em>)<a class="headerlink" href="#django.views.i18n.javascript_catalog" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<p>The main solution to these problems is the
<a class="reference internal" href="#django.views.i18n.javascript_catalog" title="django.views.i18n.javascript_catalog"><tt class="xref py py-meth docutils literal"><span class="pre">django.views.i18n.javascript_catalog()</span></tt></a> view, which sends out a JavaScript
code library with functions that mimic the <tt class="docutils literal"><span class="pre">gettext</span></tt> interface, plus an array
of translation strings. Those translation strings are taken from applications or
Django core, according to what you specify in either the <tt class="docutils literal"><span class="pre">info_dict</span></tt> or the
URL. Paths listed in <a class="reference internal" href="../../ref/settings.html#std:setting-LOCALE_PATHS"><tt class="xref std std-setting docutils literal"><span class="pre">LOCALE_PATHS</span></tt></a> are also included.</p>
<p>You hook it up like this:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">js_info_dict</span> <span class="o">=</span> <span class="p">{</span>
<span class="s">'packages'</span><span class="p">:</span> <span class="p">(</span><span class="s">'your.app.package'</span><span class="p">,),</span>
<span class="p">}</span>
<span class="n">urlpatterns</span> <span class="o">=</span> <span class="n">patterns</span><span class="p">(</span><span class="s">''</span><span class="p">,</span>
<span class="p">(</span><span class="s">r'^jsi18n/$'</span><span class="p">,</span> <span class="s">'django.views.i18n.javascript_catalog'</span><span class="p">,</span> <span class="n">js_info_dict</span><span class="p">),</span>
<span class="p">)</span>
</pre></div>
</div>
<p>Each string in <tt class="docutils literal"><span class="pre">packages</span></tt> should be in Python dotted-package syntax (the
same format as the strings in <a class="reference internal" href="../../ref/settings.html#std:setting-INSTALLED_APPS"><tt class="xref std std-setting docutils literal"><span class="pre">INSTALLED_APPS</span></tt></a>) and should refer to a
package that contains a <tt class="docutils literal"><span class="pre">locale</span></tt> directory. If you specify multiple packages,
all those catalogs are merged into one catalog. This is useful if you have
JavaScript that uses strings from different applications.</p>
<p>The precedence of translations is such that the packages appearing later in the
<tt class="docutils literal"><span class="pre">packages</span></tt> argument have higher precedence than the ones appearing at the
beginning, this is important in the case of clashing translations for the same
literal.</p>
<p>By default, the view uses the <tt class="docutils literal"><span class="pre">djangojs</span></tt> gettext domain. This can be
changed by altering the <tt class="docutils literal"><span class="pre">domain</span></tt> argument.</p>
<p>You can make the view dynamic by putting the packages into the URL pattern:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">urlpatterns</span> <span class="o">=</span> <span class="n">patterns</span><span class="p">(</span><span class="s">''</span><span class="p">,</span>
<span class="p">(</span><span class="s">r'^jsi18n/(?P<packages>\S+?)/$'</span><span class="p">,</span> <span class="s">'django.views.i18n.javascript_catalog'</span><span class="p">),</span>
<span class="p">)</span>
</pre></div>
</div>
<p>With this, you specify the packages as a list of package names delimited by ‘+’
signs in the URL. This is especially useful if your pages use code from
different apps and this changes often and you don’t want to pull in one big
catalog file. As a security measure, these values can only be either
<tt class="docutils literal"><span class="pre">django.conf</span></tt> or any package from the <a class="reference internal" href="../../ref/settings.html#std:setting-INSTALLED_APPS"><tt class="xref std std-setting docutils literal"><span class="pre">INSTALLED_APPS</span></tt></a> setting.</p>
<p>The JavaScript translations found in the paths listed in the
<a class="reference internal" href="../../ref/settings.html#std:setting-LOCALE_PATHS"><tt class="xref std std-setting docutils literal"><span class="pre">LOCALE_PATHS</span></tt></a> setting are also always included. To keep consistency
with the translations lookup order algorithm used for Python and templates, the
directories listed in <a class="reference internal" href="../../ref/settings.html#std:setting-LOCALE_PATHS"><tt class="xref std std-setting docutils literal"><span class="pre">LOCALE_PATHS</span></tt></a> have the highest precedence with
the ones appearing first having higher precedence than the ones appearing
later.</p>
<div class="versionchanged">
<span class="title">Changed in Django 1.3:</span> Directories listed in <a class="reference internal" href="../../ref/settings.html#std:setting-LOCALE_PATHS"><tt class="xref std std-setting docutils literal"><span class="pre">LOCALE_PATHS</span></tt></a> weren’t included in the
lookup algorithm until version 1.3.</div>
</div>
<div class="section" id="s-using-the-javascript-translation-catalog">
<span id="using-the-javascript-translation-catalog"></span><h3>Using the JavaScript translation catalog<a class="headerlink" href="#using-the-javascript-translation-catalog" title="Permalink to this headline">¶</a></h3>
<p>To use the catalog, just pull in the dynamically generated script like this:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="nt"><script </span><span class="na">type=</span><span class="s">"text/javascript"</span> <span class="na">src=</span><span class="s">"</span><span class="cp">{%</span> <span class="k">url</span> <span class="nv">django.views.i18n.javascript_catalog</span> <span class="cp">%}</span><span class="s">"</span><span class="nt">></script></span>
</pre></div>
</div>
<p>This uses reverse URL lookup to find the URL of the JavaScript catalog view.
When the catalog is loaded, your JavaScript code can use the standard
<tt class="docutils literal"><span class="pre">gettext</span></tt> interface to access it:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nb">document</span><span class="p">.</span><span class="nx">write</span><span class="p">(</span><span class="nx">gettext</span><span class="p">(</span><span class="s1">'this is to be translated'</span><span class="p">));</span>
</pre></div>
</div>
<p>There is also an <tt class="docutils literal"><span class="pre">ngettext</span></tt> interface:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="kd">var</span> <span class="nx">object_cnt</span> <span class="o">=</span> <span class="mi">1</span> <span class="c1">// or 0, or 2, or 3, ...</span>
<span class="nx">s</span> <span class="o">=</span> <span class="nx">ngettext</span><span class="p">(</span><span class="s1">'literal for the singular case'</span><span class="p">,</span>
<span class="s1">'literal for the plural case'</span><span class="p">,</span> <span class="nx">object_cnt</span><span class="p">);</span>
</pre></div>
</div>
<p>and even a string interpolation function:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="kd">function</span> <span class="nx">interpolate</span><span class="p">(</span><span class="nx">fmt</span><span class="p">,</span> <span class="nx">obj</span><span class="p">,</span> <span class="nx">named</span><span class="p">);</span>
</pre></div>
</div>
<p>The interpolation syntax is borrowed from Python, so the <tt class="docutils literal"><span class="pre">interpolate</span></tt>
function supports both positional and named interpolation:</p>
<ul>
<li><p class="first">Positional interpolation: <tt class="docutils literal"><span class="pre">obj</span></tt> contains a JavaScript Array object
whose elements values are then sequentially interpolated in their
corresponding <tt class="docutils literal"><span class="pre">fmt</span></tt> placeholders in the same order they appear.
For example:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">fmts</span> <span class="o">=</span> <span class="nx">ngettext</span><span class="p">(</span><span class="s1">'There is %s object. Remaining: %s'</span><span class="p">,</span>
<span class="s1">'There are %s objects. Remaining: %s'</span><span class="p">,</span> <span class="mi">11</span><span class="p">);</span>
<span class="nx">s</span> <span class="o">=</span> <span class="nx">interpolate</span><span class="p">(</span><span class="nx">fmts</span><span class="p">,</span> <span class="p">[</span><span class="mi">11</span><span class="p">,</span> <span class="mi">20</span><span class="p">]);</span>
<span class="c1">// s is 'There are 11 objects. Remaining: 20'</span>
</pre></div>
</div>
</li>
<li><p class="first">Named interpolation: This mode is selected by passing the optional
boolean <tt class="docutils literal"><span class="pre">named</span></tt> parameter as true. <tt class="docutils literal"><span class="pre">obj</span></tt> contains a JavaScript
object or associative array. For example:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">d</span> <span class="o">=</span> <span class="p">{</span>
<span class="nx">count</span><span class="o">:</span> <span class="mi">10</span><span class="p">,</span>
<span class="nx">total</span><span class="o">:</span> <span class="mi">50</span>
<span class="p">};</span>
<span class="nx">fmts</span> <span class="o">=</span> <span class="nx">ngettext</span><span class="p">(</span><span class="s1">'Total: %(total)s, there is %(count)s object'</span><span class="p">,</span>
<span class="s1">'there are %(count)s of a total of %(total)s objects'</span><span class="p">,</span> <span class="nx">d</span><span class="p">.</span><span class="nx">count</span><span class="p">);</span>
<span class="nx">s</span> <span class="o">=</span> <span class="nx">interpolate</span><span class="p">(</span><span class="nx">fmts</span><span class="p">,</span> <span class="nx">d</span><span class="p">,</span> <span class="kc">true</span><span class="p">);</span>
</pre></div>
</div>
</li>
</ul>
<p>You shouldn’t go over the top with string interpolation, though: this is still
JavaScript, so the code has to make repeated regular-expression substitutions.
This isn’t as fast as string interpolation in Python, so keep it to those
cases where you really need it (for example, in conjunction with <tt class="docutils literal"><span class="pre">ngettext</span></tt>
to produce proper pluralizations).</p>
</div>
</div>
<div class="section" id="s-internationalization-in-url-patterns">
<span id="s-url-internationalization"></span><span id="internationalization-in-url-patterns"></span><span id="url-internationalization"></span><h2>Internationalization: in URL patterns<a class="headerlink" href="#internationalization-in-url-patterns" title="Permalink to this headline">¶</a></h2>
<div class="versionadded">
<span class="title">New in Django 1.4:</span> <a class="reference internal" href="../../releases/1.4.html"><em>Please see the release notes</em></a></div>
<span class="target" id="module-django.conf.urls.i18n"></span><p>Django provides two mechanisms to internationalize URL patterns:</p>
<ul class="simple">
<li>Adding the language prefix to the root of the URL patterns to make it
possible for <a class="reference internal" href="../../ref/middleware.html#django.middleware.locale.LocaleMiddleware" title="django.middleware.locale.LocaleMiddleware"><tt class="xref py py-class docutils literal"><span class="pre">LocaleMiddleware</span></tt></a> to detect
the language to activate from the requested URL.</li>
<li>Making URL patterns themselves translatable via the
<a class="reference internal" href="../../ref/utils.html#django.utils.translation.ugettext_lazy" title="django.utils.translation.ugettext_lazy"><tt class="xref py py-func docutils literal"><span class="pre">django.utils.translation.ugettext_lazy()</span></tt></a> function.</li>
</ul>
<div class="admonition warning">
<p class="first admonition-title">Warning</p>
<p class="last">Using either one of these features requires that an active language be set
for each request; in other words, you need to have
<a class="reference internal" href="../../ref/middleware.html#django.middleware.locale.LocaleMiddleware" title="django.middleware.locale.LocaleMiddleware"><tt class="xref py py-class docutils literal"><span class="pre">django.middleware.locale.LocaleMiddleware</span></tt></a> in your
<a class="reference internal" href="../../ref/settings.html#std:setting-MIDDLEWARE_CLASSES"><tt class="xref std std-setting docutils literal"><span class="pre">MIDDLEWARE_CLASSES</span></tt></a> setting.</p>
</div>
<div class="section" id="s-language-prefix-in-url-patterns">
<span id="language-prefix-in-url-patterns"></span><h3>Language prefix in URL patterns<a class="headerlink" href="#language-prefix-in-url-patterns" title="Permalink to this headline">¶</a></h3>
<dl class="function">
<dt id="django.conf.urls.i18n.i18n_patterns">
<tt class="descname">i18n_patterns</tt>(<em>prefix</em>, <em>pattern_description</em>, <em>...</em>)<a class="headerlink" href="#django.conf.urls.i18n.i18n_patterns" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<p>This function can be used in your root URLconf as a replacement for the normal
<a class="reference internal" href="../http/urls.html#django.conf.urls.patterns" title="django.conf.urls.patterns"><tt class="xref py py-func docutils literal"><span class="pre">django.conf.urls.patterns()</span></tt></a> function. Django will automatically
prepend the current active language code to all url patterns defined within
<a class="reference internal" href="#django.conf.urls.i18n.i18n_patterns" title="django.conf.urls.i18n.i18n_patterns"><tt class="xref py py-func docutils literal"><span class="pre">i18n_patterns()</span></tt></a>. Example URL patterns:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">from</span> <span class="nx">django</span><span class="p">.</span><span class="nx">conf</span><span class="p">.</span><span class="nx">urls</span> <span class="kr">import</span> <span class="nx">patterns</span><span class="p">,</span> <span class="nx">include</span><span class="p">,</span> <span class="nx">url</span>
<span class="nx">from</span> <span class="nx">django</span><span class="p">.</span><span class="nx">conf</span><span class="p">.</span><span class="nx">urls</span><span class="p">.</span><span class="nx">i18n</span> <span class="kr">import</span> <span class="nx">i18n_patterns</span>
<span class="nx">urlpatterns</span> <span class="o">=</span> <span class="nx">patterns</span><span class="p">(</span><span class="s1">''</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^sitemap\.xml$'</span><span class="p">,</span> <span class="s1">'sitemap.view'</span><span class="p">,</span> <span class="nx">name</span><span class="o">=</span><span class="s1">'sitemap_xml'</span><span class="p">),</span>
<span class="p">)</span>
<span class="nx">news_patterns</span> <span class="o">=</span> <span class="nx">patterns</span><span class="p">(</span><span class="s1">''</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^$'</span><span class="p">,</span> <span class="s1">'news.views.index'</span><span class="p">,</span> <span class="nx">name</span><span class="o">=</span><span class="s1">'index'</span><span class="p">),</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^category/(?P<slug>[\w-]+)/$'</span><span class="p">,</span> <span class="s1">'news.views.category'</span><span class="p">,</span> <span class="nx">name</span><span class="o">=</span><span class="s1">'category'</span><span class="p">),</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^(?P<slug>[\w-]+)/$'</span><span class="p">,</span> <span class="s1">'news.views.details'</span><span class="p">,</span> <span class="nx">name</span><span class="o">=</span><span class="s1">'detail'</span><span class="p">),</span>
<span class="p">)</span>
<span class="nx">urlpatterns</span> <span class="o">+=</span> <span class="nx">i18n_patterns</span><span class="p">(</span><span class="s1">''</span><span class="p">,</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^about/$'</span><span class="p">,</span> <span class="s1">'about.view'</span><span class="p">,</span> <span class="nx">name</span><span class="o">=</span><span class="s1">'about'</span><span class="p">),</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^news/$'</span><span class="p">,</span> <span class="nx">include</span><span class="p">(</span><span class="nx">news_patterns</span><span class="p">,</span> <span class="nx">namespace</span><span class="o">=</span><span class="s1">'news'</span><span class="p">)),</span>
<span class="p">)</span>
</pre></div>
</div>
<p>After defining these URL patterns, Django will automatically add the
language prefix to the URL patterns that were added by the <tt class="docutils literal"><span class="pre">i18n_patterns</span></tt>
function. Example:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">from</span> <span class="nx">django</span><span class="p">.</span><span class="nx">core</span><span class="p">.</span><span class="nx">urlresolvers</span> <span class="kr">import</span> <span class="nx">reverse</span>
<span class="nx">from</span> <span class="nx">django</span><span class="p">.</span><span class="nx">utils</span><span class="p">.</span><span class="nx">translation</span> <span class="kr">import</span> <span class="nx">activate</span>
<span class="o">>>></span> <span class="nx">activate</span><span class="p">(</span><span class="s1">'en'</span><span class="p">)</span>
<span class="o">>>></span> <span class="nx">reverse</span><span class="p">(</span><span class="s1">'sitemap_xml'</span><span class="p">)</span>
<span class="s1">'/sitemap.xml'</span>
<span class="o">>>></span> <span class="nx">reverse</span><span class="p">(</span><span class="s1">'news:index'</span><span class="p">)</span>
<span class="s1">'/en/news/'</span>
<span class="o">>>></span> <span class="nx">activate</span><span class="p">(</span><span class="s1">'nl'</span><span class="p">)</span>
<span class="o">>>></span> <span class="nx">reverse</span><span class="p">(</span><span class="s1">'news:detail'</span><span class="p">,</span> <span class="nx">kwargs</span><span class="o">=</span><span class="p">{</span><span class="s1">'slug'</span><span class="o">:</span> <span class="s1">'news-slug'</span><span class="p">})</span>
<span class="s1">'/nl/news/news-slug/'</span>
</pre></div>
</div>
<div class="admonition warning">
<p class="first admonition-title">Warning</p>
<p class="last"><a class="reference internal" href="#django.conf.urls.i18n.i18n_patterns" title="django.conf.urls.i18n.i18n_patterns"><tt class="xref py py-func docutils literal"><span class="pre">i18n_patterns()</span></tt></a> is only allowed in your root
URLconf. Using it within an included URLconf will throw an
<tt class="xref py py-exc docutils literal"><span class="pre">ImproperlyConfigured</span></tt> exception.</p>
</div>
<div class="admonition warning">
<p class="first admonition-title">Warning</p>
<p class="last">Ensure that you don’t have non-prefixed URL patterns that might collide
with an automatically-added language prefix.</p>
</div>
</div>
<div class="section" id="s-translating-url-patterns">
<span id="translating-url-patterns"></span><h3>Translating URL patterns<a class="headerlink" href="#translating-url-patterns" title="Permalink to this headline">¶</a></h3>
<p>URL patterns can also be marked translatable using the
<a class="reference internal" href="../../ref/utils.html#django.utils.translation.ugettext_lazy" title="django.utils.translation.ugettext_lazy"><tt class="xref py py-func docutils literal"><span class="pre">ugettext_lazy()</span></tt></a> function. Example:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">from</span> <span class="nx">django</span><span class="p">.</span><span class="nx">conf</span><span class="p">.</span><span class="nx">urls</span> <span class="kr">import</span> <span class="nx">patterns</span><span class="p">,</span> <span class="nx">include</span><span class="p">,</span> <span class="nx">url</span>
<span class="nx">from</span> <span class="nx">django</span><span class="p">.</span><span class="nx">conf</span><span class="p">.</span><span class="nx">urls</span><span class="p">.</span><span class="nx">i18n</span> <span class="kr">import</span> <span class="nx">i18n_patterns</span>
<span class="nx">from</span> <span class="nx">django</span><span class="p">.</span><span class="nx">utils</span><span class="p">.</span><span class="nx">translation</span> <span class="kr">import</span> <span class="nx">ugettext_lazy</span> <span class="nx">as</span> <span class="nx">_</span>
<span class="nx">urlpatterns</span> <span class="o">=</span> <span class="nx">patterns</span><span class="p">(</span><span class="s1">''</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^sitemap\.xml$'</span><span class="p">,</span> <span class="s1">'sitemap.view'</span><span class="p">,</span> <span class="nx">name</span><span class="o">=</span><span class="s1">'sitemap_xml'</span><span class="p">),</span>
<span class="p">)</span>
<span class="nx">news_patterns</span> <span class="o">=</span> <span class="nx">patterns</span><span class="p">(</span><span class="s1">''</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^$'</span><span class="p">,</span> <span class="s1">'news.views.index'</span><span class="p">,</span> <span class="nx">name</span><span class="o">=</span><span class="s1">'index'</span><span class="p">),</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">_</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^category/(?P<slug>[\w-]+)/$'</span><span class="p">),</span> <span class="s1">'news.views.category'</span><span class="p">,</span> <span class="nx">name</span><span class="o">=</span><span class="s1">'category'</span><span class="p">),</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^(?P<slug>[\w-]+)/$'</span><span class="p">,</span> <span class="s1">'news.views.details'</span><span class="p">,</span> <span class="nx">name</span><span class="o">=</span><span class="s1">'detail'</span><span class="p">),</span>
<span class="p">)</span>
<span class="nx">urlpatterns</span> <span class="o">+=</span> <span class="nx">i18n_patterns</span><span class="p">(</span><span class="s1">''</span><span class="p">,</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">_</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^about/$'</span><span class="p">),</span> <span class="s1">'about.view'</span><span class="p">,</span> <span class="nx">name</span><span class="o">=</span><span class="s1">'about'</span><span class="p">),</span>
<span class="nx">url</span><span class="p">(</span><span class="nx">_</span><span class="p">(</span><span class="nx">r</span><span class="s1">'^news/$'</span><span class="p">),</span> <span class="nx">include</span><span class="p">(</span><span class="nx">news_patterns</span><span class="p">,</span> <span class="nx">namespace</span><span class="o">=</span><span class="s1">'news'</span><span class="p">)),</span>
<span class="p">)</span>
</pre></div>
</div>
<p>After you’ve created the translations, the
<a class="reference internal" href="../http/urls.html#django.core.urlresolvers.reverse" title="django.core.urlresolvers.reverse"><tt class="xref py py-func docutils literal"><span class="pre">reverse()</span></tt></a> function will return the URL in the
active language. Example:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">from</span> <span class="nx">django</span><span class="p">.</span><span class="nx">core</span><span class="p">.</span><span class="nx">urlresolvers</span> <span class="kr">import</span> <span class="nx">reverse</span>
<span class="nx">from</span> <span class="nx">django</span><span class="p">.</span><span class="nx">utils</span><span class="p">.</span><span class="nx">translation</span> <span class="kr">import</span> <span class="nx">activate</span>
<span class="o">>>></span> <span class="nx">activate</span><span class="p">(</span><span class="s1">'en'</span><span class="p">)</span>
<span class="o">>>></span> <span class="nx">reverse</span><span class="p">(</span><span class="s1">'news:category'</span><span class="p">,</span> <span class="nx">kwargs</span><span class="o">=</span><span class="p">{</span><span class="s1">'slug'</span><span class="o">:</span> <span class="s1">'recent'</span><span class="p">})</span>
<span class="s1">'/en/news/category/recent/'</span>
<span class="o">>>></span> <span class="nx">activate</span><span class="p">(</span><span class="s1">'nl'</span><span class="p">)</span>
<span class="o">>>></span> <span class="nx">reverse</span><span class="p">(</span><span class="s1">'news:category'</span><span class="p">,</span> <span class="nx">kwargs</span><span class="o">=</span><span class="p">{</span><span class="s1">'slug'</span><span class="o">:</span> <span class="s1">'recent'</span><span class="p">})</span>
<span class="s1">'/nl/nieuws/categorie/recent/'</span>
</pre></div>
</div>
<div class="admonition warning">
<p class="first admonition-title">Warning</p>
<p class="last">In most cases, it’s best to use translated URLs only within a
language-code-prefixed block of patterns (using
<a class="reference internal" href="#django.conf.urls.i18n.i18n_patterns" title="django.conf.urls.i18n.i18n_patterns"><tt class="xref py py-func docutils literal"><span class="pre">i18n_patterns()</span></tt></a>), to avoid the possibility
that a carelessly translated URL causes a collision with a non-translated
URL pattern.</p>
</div>
<span class="target" id="reversing-in-templates"></span></div>
<div class="section" id="s-std:templatetag-language">
<span id="s-id2"></span><span id="std:templatetag-language"></span><span id="id2"></span><h3>Reversing in templates<a class="headerlink" href="#std:templatetag-language" title="Permalink to this headline">¶</a></h3>
<p>If localized URLs get reversed in templates they always use the current
language. To link to a URL in another language use the <tt class="docutils literal"><span class="pre">language</span></tt>
template tag. It enables the given language in the enclosed template section:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="cp">{%</span> <span class="k">load</span> <span class="nv">i18n</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">get_available_languages</span> <span class="k">as</span> <span class="nv">languages</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">trans</span> <span class="s2">"View this category in:"</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">for</span> <span class="nv">lang_code</span><span class="o">,</span> <span class="nv">lang_name</span> <span class="k">in</span> <span class="nv">languages</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">language</span> <span class="nv">lang_code</span> <span class="cp">%}</span>
<span class="nt"><a</span> <span class="na">href=</span><span class="s">"</span><span class="cp">{%</span> <span class="k">url</span> <span class="nv">category</span> <span class="nv">slug</span><span class="o">=</span><span class="nv">category.slug</span> <span class="cp">%}</span><span class="s">"</span><span class="nt">></span><span class="cp">{{</span> <span class="nv">lang_name</span> <span class="cp">}}</span><span class="nt"></a></span>
<span class="cp">{%</span> <span class="k">endlanguage</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span>
</pre></div>
</div>
<p>The <a class="reference internal" href="#std:templatetag-language"><tt class="xref std std-ttag docutils literal"><span class="pre">language</span></tt></a> tag expects the language code as the only argument.</p>
</div>
</div>
<div class="section" id="s-localization-how-to-create-language-files">
<span id="s-how-to-create-language-files"></span><span id="localization-how-to-create-language-files"></span><span id="how-to-create-language-files"></span><h2>Localization: how to create language files<a class="headerlink" href="#localization-how-to-create-language-files" title="Permalink to this headline">¶</a></h2>
<p>Once the string literals of an application have been tagged for later
translation, the translation themselves need to be written (or obtained). Here’s
how that works.</p>
<div class="admonition-locale-restrictions admonition" id="locale-restrictions">
<p class="first admonition-title">Locale restrictions</p>
<p>Django does not support localizing your application into a locale for which
Django itself has not been translated. In this case, it will ignore your
translation files. If you were to try this and Django supported it, you
would inevitably see a mixture of translated strings (from your application)
and English strings (from Django itself). If you want to support a locale
for your application that is not already part of Django, you’ll need to make
at least a minimal translation of the Django core.</p>
<p class="last">A good starting point is to copy the Django English <tt class="docutils literal"><span class="pre">.po</span></tt> file and to
translate at least some <a class="reference internal" href="index.html#term-translation-string"><em class="xref std std-term">translation strings</em></a>.</p>
</div>
<div class="section" id="s-message-files">
<span id="message-files"></span><h3>Message files<a class="headerlink" href="#message-files" title="Permalink to this headline">¶</a></h3>
<p>The first step is to create a <a class="reference internal" href="index.html#term-message-file"><em class="xref std std-term">message file</em></a> for a new language. A message
file is a plain-text file, representing a single language, that contains all
available translation strings and how they should be represented in the given
language. Message files have a <tt class="docutils literal"><span class="pre">.po</span></tt> file extension.</p>
<p>Django comes with a tool, <a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">makemessages</span></tt></a>, that automates the creation and upkeep of these files.</p>
<div class="admonition-gettext-utilities admonition">
<p class="first admonition-title">Gettext utilities</p>
<p>The <tt class="docutils literal"><span class="pre">makemessages</span></tt> command (and <tt class="docutils literal"><span class="pre">compilemessages</span></tt> discussed later) use
commands from the GNU gettext toolset: <tt class="docutils literal"><span class="pre">xgettext</span></tt>, <tt class="docutils literal"><span class="pre">msgfmt</span></tt>,
<tt class="docutils literal"><span class="pre">msgmerge</span></tt> and <tt class="docutils literal"><span class="pre">msguniq</span></tt>.</p>
<div class="versionchanged">
<span class="title">Changed in Django 1.2:</span> <a class="reference internal" href="../../releases/1.2.html"><em>Please see the release notes</em></a></div>
<p class="last">The minimum version of the <tt class="docutils literal"><span class="pre">gettext</span></tt> utilities supported is 0.15.</p>
</div>
<p>To create or update a message file, run this command:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">django</span><span class="o">-</span><span class="nx">admin</span><span class="p">.</span><span class="nx">py</span> <span class="nx">makemessages</span> <span class="o">-</span><span class="nx">l</span> <span class="nx">de</span>
</pre></div>
</div>
<p>...where <tt class="docutils literal"><span class="pre">de</span></tt> is the language code for the message file you want to create.
The language code, in this case, is in <a class="reference internal" href="index.html#term-locale-name"><em class="xref std std-term">locale format</em></a>. For
example, it’s <tt class="docutils literal"><span class="pre">pt_BR</span></tt> for Brazilian Portuguese and <tt class="docutils literal"><span class="pre">de_AT</span></tt> for Austrian
German.</p>
<p>The script should be run from one of two places:</p>
<ul class="simple">
<li>The root directory of your Django project.</li>
<li>The root directory of your Django app.</li>
</ul>
<p>The script runs over your project source tree or your application source tree
and pulls out all strings marked for translation. It creates (or updates) a
message file in the directory <tt class="docutils literal"><span class="pre">locale/LANG/LC_MESSAGES</span></tt>. In the <tt class="docutils literal"><span class="pre">de</span></tt>
example, the file will be <tt class="docutils literal"><span class="pre">locale/de/LC_MESSAGES/django.po</span></tt>.</p>
<p>By default <a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">makemessages</span></tt></a> examines every
file that has the <tt class="docutils literal"><span class="pre">.html</span></tt> or <tt class="docutils literal"><span class="pre">.txt</span></tt> file extension. In case you want to
override that default, use the <tt class="docutils literal"><span class="pre">--extension</span></tt> or <tt class="docutils literal"><span class="pre">-e</span></tt> option to specify the
file extensions to examine:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">django</span><span class="o">-</span><span class="nx">admin</span><span class="p">.</span><span class="nx">py</span> <span class="nx">makemessages</span> <span class="o">-</span><span class="nx">l</span> <span class="nx">de</span> <span class="o">-</span><span class="nx">e</span> <span class="nx">txt</span>
</pre></div>
</div>
<p>Separate multiple extensions with commas and/or use <tt class="docutils literal"><span class="pre">-e</span></tt> or <tt class="docutils literal"><span class="pre">--extension</span></tt>
multiple times:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">django</span><span class="o">-</span><span class="nx">admin</span><span class="p">.</span><span class="nx">py</span> <span class="nx">makemessages</span> <span class="o">-</span><span class="nx">l</span> <span class="nx">de</span> <span class="o">-</span><span class="nx">e</span> <span class="nx">html</span><span class="p">,</span><span class="nx">txt</span> <span class="o">-</span><span class="nx">e</span> <span class="nx">xml</span>
</pre></div>
</div>
<div class="admonition warning">
<p class="first admonition-title">Warning</p>
<p class="last">When <a class="reference internal" href="#creating-message-files-from-js-code"><em>creating message files from JavaScript source code</em></a> you need to use the special
‘djangojs’ domain, <strong>not</strong> <tt class="docutils literal"><span class="pre">-e</span> <span class="pre">js</span></tt>.</p>
</div>
<div class="admonition-no-gettext admonition">
<p class="first admonition-title">No gettext?</p>
<p class="last">If you don’t have the <tt class="docutils literal"><span class="pre">gettext</span></tt> utilities installed,
<a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">makemessages</span></tt></a> will create empty files. If that’s the case, either
install the <tt class="docutils literal"><span class="pre">gettext</span></tt> utilities or just copy the English message file
(<tt class="docutils literal"><span class="pre">locale/en/LC_MESSAGES/django.po</span></tt>) if available and use it as a starting
point; it’s just an empty translation file.</p>
</div>
<div class="admonition-working-on-windows admonition">
<p class="first admonition-title">Working on Windows?</p>
<p class="last">If you’re using Windows and need to install the GNU gettext utilities so
<a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">makemessages</span></tt></a> works, see <a class="reference internal" href="#gettext-on-windows"><em>gettext on Windows</em></a> for more
information.</p>
</div>
<p>The format of <tt class="docutils literal"><span class="pre">.po</span></tt> files is straightforward. Each <tt class="docutils literal"><span class="pre">.po</span></tt> file contains a
small bit of metadata, such as the translation maintainer’s contact
information, but the bulk of the file is a list of <strong>messages</strong> – simple
mappings between translation strings and the actual translated text for the
particular language.</p>
<p>For example, if your Django app contained a translation string for the text
<tt class="docutils literal"><span class="pre">"Welcome</span> <span class="pre">to</span> <span class="pre">my</span> <span class="pre">site."</span></tt>, like so:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">_</span><span class="p">(</span><span class="s2">"Welcome to my site."</span><span class="p">)</span>
</pre></div>
</div>
<p>...then <a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">makemessages</span></tt></a> will have created
a <tt class="docutils literal"><span class="pre">.po</span></tt> file containing the following snippet – a message:</p>
<div class="highlight-javascript"><pre>#: path/to/python/module.py:23
msgid "Welcome to my site."
msgstr ""</pre>
</div>
<p>A quick explanation:</p>
<ul class="simple">
<li><tt class="docutils literal"><span class="pre">msgid</span></tt> is the translation string, which appears in the source. Don’t
change it.</li>
<li><tt class="docutils literal"><span class="pre">msgstr</span></tt> is where you put the language-specific translation. It starts
out empty, so it’s your responsibility to change it. Make sure you keep
the quotes around your translation.</li>
<li>As a convenience, each message includes, in the form of a comment line
prefixed with <tt class="docutils literal"><span class="pre">#</span></tt> and located above the <tt class="docutils literal"><span class="pre">msgid</span></tt> line, the filename and
line number from which the translation string was gleaned.</li>
</ul>
<p>Long messages are a special case. There, the first string directly after the
<tt class="docutils literal"><span class="pre">msgstr</span></tt> (or <tt class="docutils literal"><span class="pre">msgid</span></tt>) is an empty string. Then the content itself will be
written over the next few lines as one string per line. Those strings are
directly concatenated. Don’t forget trailing spaces within the strings;
otherwise, they’ll be tacked together without whitespace!</p>
<div class="admonition-mind-your-charset admonition">
<p class="first admonition-title">Mind your charset</p>
<p class="last">When creating a PO file with your favorite text editor, first edit
the charset line (search for <tt class="docutils literal"><span class="pre">"CHARSET"</span></tt>) and set it to the charset
you’ll be using to edit the content. Due to the way the <tt class="docutils literal"><span class="pre">gettext</span></tt> tools
work internally and because we want to allow non-ASCII source strings in
Django’s core and your applications, you <strong>must</strong> use UTF-8 as the encoding
for your PO file. This means that everybody will be using the same
encoding, which is important when Django processes the PO files.</p>
</div>
<p>To reexamine all source code and templates for new translation strings and
update all message files for <strong>all</strong> languages, run this:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">django</span><span class="o">-</span><span class="nx">admin</span><span class="p">.</span><span class="nx">py</span> <span class="nx">makemessages</span> <span class="o">-</span><span class="nx">a</span>
</pre></div>
</div>
</div>
<div class="section" id="s-compiling-message-files">
<span id="compiling-message-files"></span><h3>Compiling message files<a class="headerlink" href="#compiling-message-files" title="Permalink to this headline">¶</a></h3>
<p>After you create your message file – and each time you make changes to it –
you’ll need to compile it into a more efficient form, for use by <tt class="docutils literal"><span class="pre">gettext</span></tt>. Do
this with the <a class="reference internal" href="../../ref/django-admin.html#django-admin-compilemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">compilemessages</span></tt></a>
utility.</p>
<p>This tool runs over all available <tt class="docutils literal"><span class="pre">.po</span></tt> files and creates <tt class="docutils literal"><span class="pre">.mo</span></tt> files, which
are binary files optimized for use by <tt class="docutils literal"><span class="pre">gettext</span></tt>. In the same directory from
which you ran <a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">makemessages</span></tt></a>, run <a class="reference internal" href="../../ref/django-admin.html#django-admin-compilemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">compilemessages</span></tt></a> like this:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">django</span><span class="o">-</span><span class="nx">admin</span><span class="p">.</span><span class="nx">py</span> <span class="nx">compilemessages</span>
</pre></div>
</div>
<p>That’s it. Your translations are ready for use.</p>
<div class="admonition-working-on-windows admonition">
<p class="first admonition-title">Working on Windows?</p>
<p class="last">If you’re using Windows and need to install the GNU gettext utilities so
<a class="reference internal" href="../../ref/django-admin.html#django-admin-compilemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">compilemessages</span></tt></a> works see
<a class="reference internal" href="#gettext-on-windows"><em>gettext on Windows</em></a> for more information.</p>
</div>
<div class="admonition-po-files-encoding-and-bom-usage admonition">
<p class="first admonition-title">.po files: Encoding and BOM usage.</p>
<p class="last">Django only supports <tt class="docutils literal"><span class="pre">.po</span></tt> files encoded in UTF-8 and without any BOM
(Byte Order Mark) so if your text editor adds such marks to the beginning of
files by default then you will need to reconfigure it.</p>
</div>
</div>
<div class="section" id="s-creating-message-files-from-javascript-source-code">
<span id="s-creating-message-files-from-js-code"></span><span id="creating-message-files-from-javascript-source-code"></span><span id="creating-message-files-from-js-code"></span><h3>Creating message files from JavaScript source code<a class="headerlink" href="#creating-message-files-from-javascript-source-code" title="Permalink to this headline">¶</a></h3>
<p>You create and update the message files the same way as the other Django message
files – with the <a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">makemessages</span></tt></a> tool.
The only difference is you need to explicitly specify what in gettext parlance
is known as a domain in this case the <tt class="docutils literal"><span class="pre">djangojs</span></tt> domain, by providing a <tt class="docutils literal"><span class="pre">-d</span>
<span class="pre">djangojs</span></tt> parameter, like this:</p>
<div class="highlight-javascript"><div class="highlight"><pre><span class="nx">django</span><span class="o">-</span><span class="nx">admin</span><span class="p">.</span><span class="nx">py</span> <span class="nx">makemessages</span> <span class="o">-</span><span class="nx">d</span> <span class="nx">djangojs</span> <span class="o">-</span><span class="nx">l</span> <span class="nx">de</span>
</pre></div>
</div>
<p>This would create or update the message file for JavaScript for German. After
updating message files, just run <a class="reference internal" href="../../ref/django-admin.html#django-admin-compilemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">compilemessages</span></tt></a> the same way as you do with normal Django message files.</p>
</div>
<div class="section" id="s-gettext-on-windows">
<span id="s-id3"></span><span id="gettext-on-windows"></span><span id="id3"></span><h3><tt class="docutils literal"><span class="pre">gettext</span></tt> on Windows<a class="headerlink" href="#gettext-on-windows" title="Permalink to this headline">¶</a></h3>
<p>This is only needed for people who either want to extract message IDs or compile
message files (<tt class="docutils literal"><span class="pre">.po</span></tt>). Translation work itself just involves editing existing
files of this type, but if you want to create your own message files, or want to
test or compile a changed message file, you will need the <tt class="docutils literal"><span class="pre">gettext</span></tt> utilities:</p>
<ul>
<li><p class="first">Download the following zip files from the GNOME servers
<a class="reference external" href="http://ftp.gnome.org/pub/gnome/binaries/win32/dependencies/">http://ftp.gnome.org/pub/gnome/binaries/win32/dependencies/</a> or from one
of its <a class="reference external" href="http://ftp.gnome.org/pub/GNOME/MIRRORS">mirrors</a></p>
<ul class="simple">
<li><tt class="docutils literal"><span class="pre">gettext-runtime-X.zip</span></tt></li>
<li><tt class="docutils literal"><span class="pre">gettext-tools-X.zip</span></tt></li>
</ul>
<p><tt class="docutils literal"><span class="pre">X</span></tt> is the version number, we are requiring <tt class="docutils literal"><span class="pre">0.15</span></tt> or higher.</p>
</li>
<li><p class="first">Extract the contents of the <tt class="docutils literal"><span class="pre">bin\</span></tt> directories in both files to the
same folder on your system (i.e. <tt class="docutils literal"><span class="pre">C:\Program</span> <span class="pre">Files\gettext-utils</span></tt>)</p>
</li>
<li><p class="first">Update the system PATH:</p>
<ul class="simple">
<li><tt class="docutils literal"><span class="pre">Control</span> <span class="pre">Panel</span> <span class="pre">></span> <span class="pre">System</span> <span class="pre">></span> <span class="pre">Advanced</span> <span class="pre">></span> <span class="pre">Environment</span> <span class="pre">Variables</span></tt>.</li>
<li>In the <tt class="docutils literal"><span class="pre">System</span> <span class="pre">variables</span></tt> list, click <tt class="docutils literal"><span class="pre">Path</span></tt>, click <tt class="docutils literal"><span class="pre">Edit</span></tt>.</li>
<li>Add <tt class="docutils literal"><span class="pre">;C:\Program</span> <span class="pre">Files\gettext-utils\bin</span></tt> at the end of the
<tt class="docutils literal"><span class="pre">Variable</span> <span class="pre">value</span></tt> field.</li>
</ul>
</li>
</ul>
<p>You may also use <tt class="docutils literal"><span class="pre">gettext</span></tt> binaries you have obtained elsewhere, so long as
the <tt class="docutils literal"><span class="pre">xgettext</span> <span class="pre">--version</span></tt> command works properly. Do not attempt to use Django
translation utilities with a <tt class="docutils literal"><span class="pre">gettext</span></tt> package if the command <tt class="docutils literal"><span class="pre">xgettext</span>
<span class="pre">--version</span></tt> entered at a Windows command prompt causes a popup window saying
“xgettext.exe has generated errors and will be closed by Windows”.</p>
</div>
</div>
<div class="section" id="s-miscellaneous">
<span id="miscellaneous"></span><h2>Miscellaneous<a class="headerlink" href="#miscellaneous" title="Permalink to this headline">¶</a></h2>
<div class="section" id="s-the-set-language-redirect-view">
<span id="s-set-language-redirect-view"></span><span id="the-set-language-redirect-view"></span><span id="set-language-redirect-view"></span><h3>The <tt class="docutils literal"><span class="pre">set_language</span></tt> redirect view<a class="headerlink" href="#the-set-language-redirect-view" title="Permalink to this headline">¶</a></h3>
<dl class="function">
<dt id="django.conf.urls.i18n.set_language">
<tt class="descname">set_language</tt>(<em>request</em>)<a class="headerlink" href="#django.conf.urls.i18n.set_language" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>
<p>As a convenience, Django comes with a view, <tt class="xref py py-func docutils literal"><span class="pre">django.views.i18n.set_language()</span></tt>,
that sets a user’s language preference and redirects to a given URL or, by default,
back to the previous page.</p>
<p>Activate this view by adding the following line to your URLconf:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="p">(</span><span class="s">r'^i18n/'</span><span class="p">,</span> <span class="n">include</span><span class="p">(</span><span class="s">'django.conf.urls.i18n'</span><span class="p">)),</span>
</pre></div>
</div>
<p>(Note that this example makes the view available at <tt class="docutils literal"><span class="pre">/i18n/setlang/</span></tt>.)</p>
<div class="admonition warning">
<p class="first admonition-title">Warning</p>
<p class="last">Make sure that you don’t include the above URL within
<a class="reference internal" href="#django.conf.urls.i18n.i18n_patterns" title="django.conf.urls.i18n.i18n_patterns"><tt class="xref py py-func docutils literal"><span class="pre">i18n_patterns()</span></tt></a> - it needs to be
language-independent itself to work correctly.</p>
</div>
<p>The view expects to be called via the <tt class="docutils literal"><span class="pre">POST</span></tt> method, with a <tt class="docutils literal"><span class="pre">language</span></tt>
parameter set in request. If session support is enabled, the view
saves the language choice in the user’s session. Otherwise, it saves the
language choice in a cookie that is by default named <tt class="docutils literal"><span class="pre">django_language</span></tt>.
(The name can be changed through the <a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGE_COOKIE_NAME"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGE_COOKIE_NAME</span></tt></a> setting.)</p>
<p>After setting the language choice, Django redirects the user, following this
algorithm:</p>
<ul class="simple">
<li>Django looks for a <tt class="docutils literal"><span class="pre">next</span></tt> parameter in the <tt class="docutils literal"><span class="pre">POST</span></tt> data.</li>
<li>If that doesn’t exist, or is empty, Django tries the URL in the
<tt class="docutils literal"><span class="pre">Referrer</span></tt> header.</li>
<li>If that’s empty – say, if a user’s browser suppresses that header –
then the user will be redirected to <tt class="docutils literal"><span class="pre">/</span></tt> (the site root) as a fallback.</li>
</ul>
<p>Here’s example HTML template code:</p>
<div class="highlight-html+django"><div class="highlight"><pre><span class="nt"><form</span> <span class="na">action=</span><span class="s">"/i18n/setlang/"</span> <span class="na">method=</span><span class="s">"post"</span><span class="nt">></span>
<span class="cp">{%</span> <span class="k">csrf_token</span> <span class="cp">%}</span>
<span class="nt"><input</span> <span class="na">name=</span><span class="s">"next"</span> <span class="na">type=</span><span class="s">"hidden"</span> <span class="na">value=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">redirect_to</span> <span class="cp">}}</span><span class="s">"</span> <span class="nt">/></span>
<span class="nt"><select</span> <span class="na">name=</span><span class="s">"language"</span><span class="nt">></span>
<span class="cp">{%</span> <span class="k">get_language_info_list</span> <span class="nv">for</span> <span class="nv">LANGUAGES</span> <span class="k">as</span> <span class="nv">languages</span> <span class="cp">%}</span>
<span class="cp">{%</span> <span class="k">for</span> <span class="nv">language</span> <span class="k">in</span> <span class="nv">languages</span> <span class="cp">%}</span>
<span class="nt"><option</span> <span class="na">value=</span><span class="s">"</span><span class="cp">{{</span> <span class="nv">language.code</span> <span class="cp">}}</span><span class="s">"</span><span class="nt">></span><span class="cp">{{</span> <span class="nv">language.name_local</span> <span class="cp">}}</span> (<span class="cp">{{</span> <span class="nv">language.code</span> <span class="cp">}}</span>)<span class="nt"></option></span>
<span class="cp">{%</span> <span class="k">endfor</span> <span class="cp">%}</span>
<span class="nt"></select></span>
<span class="nt"><input</span> <span class="na">type=</span><span class="s">"submit"</span> <span class="na">value=</span><span class="s">"Go"</span> <span class="nt">/></span>
<span class="nt"></form></span>
</pre></div>
</div>
<p>In this example, Django looks up the URL of the page to which the user will be
redirected in the <tt class="docutils literal"><span class="pre">redirect_to</span></tt> context variable.</p>
</div>
<div class="section" id="s-using-translations-outside-views-and-templates">
<span id="using-translations-outside-views-and-templates"></span><h3>Using translations outside views and templates<a class="headerlink" href="#using-translations-outside-views-and-templates" title="Permalink to this headline">¶</a></h3>
<p>While Django provides a rich set of i18n tools for use in views and templates,
it does not restrict the usage to Django-specific code. The Django translation
mechanisms can be used to translate arbitrary texts to any language that is
supported by Django (as long as an appropriate translation catalog exists, of
course). You can load a translation catalog, activate it and translate text to
language of your choice, but remember to switch back to original language, as
activating a translation catalog is done on per-thread basis and such change
will affect code running in the same thread.</p>
<p>For example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">django.utils</span> <span class="kn">import</span> <span class="n">translation</span>
<span class="k">def</span> <span class="nf">welcome_translated</span><span class="p">(</span><span class="n">language</span><span class="p">):</span>
<span class="n">cur_language</span> <span class="o">=</span> <span class="n">translation</span><span class="o">.</span><span class="n">get_language</span><span class="p">()</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">translation</span><span class="o">.</span><span class="n">activate</span><span class="p">(</span><span class="n">language</span><span class="p">)</span>
<span class="n">text</span> <span class="o">=</span> <span class="n">translation</span><span class="o">.</span><span class="n">ugettext</span><span class="p">(</span><span class="s">'welcome'</span><span class="p">)</span>
<span class="k">finally</span><span class="p">:</span>
<span class="n">translation</span><span class="o">.</span><span class="n">activate</span><span class="p">(</span><span class="n">cur_language</span><span class="p">)</span>
<span class="k">return</span> <span class="n">text</span>
</pre></div>
</div>
<p>Calling this function with the value ‘de’ will give you <tt class="docutils literal"><span class="pre">"Willkommen"</span></tt>,
regardless of <a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGE_CODE"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGE_CODE</span></tt></a> and language set by middleware.</p>
<p>Functions of particular interest are <tt class="docutils literal"><span class="pre">django.utils.translation.get_language()</span></tt>
which returns the language used in the current thread,
<tt class="docutils literal"><span class="pre">django.utils.translation.activate()</span></tt> which activates a translation catalog
for the current thread, and <tt class="docutils literal"><span class="pre">django.utils.translation.check_for_language()</span></tt>
which checks if the given language is supported by Django.</p>
</div>
</div>
<div class="section" id="s-implementation-notes">
<span id="implementation-notes"></span><h2>Implementation notes<a class="headerlink" href="#implementation-notes" title="Permalink to this headline">¶</a></h2>
<div class="section" id="s-specialties-of-django-translation">
<span id="s-specialties-of-django-i18n"></span><span id="specialties-of-django-translation"></span><span id="specialties-of-django-i18n"></span><h3>Specialties of Django translation<a class="headerlink" href="#specialties-of-django-translation" title="Permalink to this headline">¶</a></h3>
<p>Django’s translation machinery uses the standard <tt class="docutils literal"><span class="pre">gettext</span></tt> module that comes
with Python. If you know <tt class="docutils literal"><span class="pre">gettext</span></tt>, you might note these specialties in the
way Django does translation:</p>
<ul class="simple">
<li>The string domain is <tt class="docutils literal"><span class="pre">django</span></tt> or <tt class="docutils literal"><span class="pre">djangojs</span></tt>. This string domain is
used to differentiate between different programs that store their data
in a common message-file library (usually <tt class="docutils literal"><span class="pre">/usr/share/locale/</span></tt>). The
<tt class="docutils literal"><span class="pre">django</span></tt> domain is used for python and template translation strings
and is loaded into the global translation catalogs. The <tt class="docutils literal"><span class="pre">djangojs</span></tt>
domain is only used for JavaScript translation catalogs to make sure
that those are as small as possible.</li>
<li>Django doesn’t use <tt class="docutils literal"><span class="pre">xgettext</span></tt> alone. It uses Python wrappers around
<tt class="docutils literal"><span class="pre">xgettext</span></tt> and <tt class="docutils literal"><span class="pre">msgfmt</span></tt>. This is mostly for convenience.</li>
</ul>
</div>
<div class="section" id="s-how-django-discovers-language-preference">
<span id="s-id4"></span><span id="how-django-discovers-language-preference"></span><span id="id4"></span><h3>How Django discovers language preference<a class="headerlink" href="#how-django-discovers-language-preference" title="Permalink to this headline">¶</a></h3>
<p>Once you’ve prepared your translations – or, if you just want to use the
translations that come with Django – you’ll just need to activate translation
for your app.</p>
<p>Behind the scenes, Django has a very flexible model of deciding which language
should be used – installation-wide, for a particular user, or both.</p>
<p>To set an installation-wide language preference, set <a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGE_CODE"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGE_CODE</span></tt></a>.
Django uses this language as the default translation – the final attempt if no
other translator finds a translation.</p>
<p>If all you want to do is run Django with your native language, and a language
file is available for it, all you need to do is set <a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGE_CODE"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGE_CODE</span></tt></a>.</p>
<p>If you want to let each individual user specify which language he or she
prefers, use <tt class="docutils literal"><span class="pre">LocaleMiddleware</span></tt>. <tt class="docutils literal"><span class="pre">LocaleMiddleware</span></tt> enables language
selection based on data from the request. It customizes content for each user.</p>
<p>To use <tt class="docutils literal"><span class="pre">LocaleMiddleware</span></tt>, add <tt class="docutils literal"><span class="pre">'django.middleware.locale.LocaleMiddleware'</span></tt>
to your <a class="reference internal" href="../../ref/settings.html#std:setting-MIDDLEWARE_CLASSES"><tt class="xref std std-setting docutils literal"><span class="pre">MIDDLEWARE_CLASSES</span></tt></a> setting. Because middleware order
matters, you should follow these guidelines:</p>
<ul class="simple">
<li>Make sure it’s one of the first middlewares installed.</li>
<li>It should come after <tt class="docutils literal"><span class="pre">SessionMiddleware</span></tt>, because <tt class="docutils literal"><span class="pre">LocaleMiddleware</span></tt>
makes use of session data. And it should come before <tt class="docutils literal"><span class="pre">CommonMiddleware</span></tt>
because <tt class="docutils literal"><span class="pre">CommonMiddleware</span></tt> needs an activated language in order
to resolve the requested URL.</li>
<li>If you use <tt class="docutils literal"><span class="pre">CacheMiddleware</span></tt>, put <tt class="docutils literal"><span class="pre">LocaleMiddleware</span></tt> after it.</li>
</ul>
<p>For example, your <a class="reference internal" href="../../ref/settings.html#std:setting-MIDDLEWARE_CLASSES"><tt class="xref std std-setting docutils literal"><span class="pre">MIDDLEWARE_CLASSES</span></tt></a> might look like this:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">MIDDLEWARE_CLASSES</span> <span class="o">=</span> <span class="p">(</span>
<span class="s">'django.contrib.sessions.middleware.SessionMiddleware'</span><span class="p">,</span>
<span class="s">'django.middleware.locale.LocaleMiddleware'</span><span class="p">,</span>
<span class="s">'django.middleware.common.CommonMiddleware'</span><span class="p">,</span>
<span class="p">)</span>
</pre></div>
</div>
<p>(For more on middleware, see the <a class="reference internal" href="../http/middleware.html"><em>middleware documentation</em></a>.)</p>
<p><tt class="docutils literal"><span class="pre">LocaleMiddleware</span></tt> tries to determine the user’s language preference by
following this algorithm:</p>
<div class="versionchanged">
<span class="title">Changed in Django 1.4:</span> <a class="reference internal" href="../../releases/1.4.html"><em>Please see the release notes</em></a></div>
<ul>
<li><p class="first">First, it looks for the language prefix in the requested URL. This is
only performed when you are using the <tt class="docutils literal"><span class="pre">i18n_patterns</span></tt> function in your
root URLconf. See <a class="reference internal" href="#url-internationalization"><em>Internationalization: in URL patterns</em></a> for more information
about the language prefix and how to internationalize URL patterns.</p>
</li>
<li><p class="first">Failing that, it looks for a <tt class="docutils literal"><span class="pre">django_language</span></tt> key in the current
user’s session.</p>
</li>
<li><p class="first">Failing that, it looks for a cookie.</p>
<p>The name of the cookie used is set by the <a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGE_COOKIE_NAME"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGE_COOKIE_NAME</span></tt></a>
setting. (The default name is <tt class="docutils literal"><span class="pre">django_language</span></tt>.)</p>
</li>
<li><p class="first">Failing that, it looks at the <tt class="docutils literal"><span class="pre">Accept-Language</span></tt> HTTP header. This
header is sent by your browser and tells the server which language(s) you
prefer, in order by priority. Django tries each language in the header
until it finds one with available translations.</p>
</li>
<li><p class="first">Failing that, it uses the global <a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGE_CODE"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGE_CODE</span></tt></a> setting.</p>
</li>
</ul>
<p id="locale-middleware-notes">Notes:</p>
<ul>
<li><p class="first">In each of these places, the language preference is expected to be in the
standard <a class="reference internal" href="index.html#term-language-code"><em class="xref std std-term">language format</em></a>, as a string. For example,
Brazilian Portuguese is <tt class="docutils literal"><span class="pre">pt-br</span></tt>.</p>
</li>
<li><p class="first">If a base language is available but the sublanguage specified is not,
Django uses the base language. For example, if a user specifies <tt class="docutils literal"><span class="pre">de-at</span></tt>
(Austrian German) but Django only has <tt class="docutils literal"><span class="pre">de</span></tt> available, Django uses
<tt class="docutils literal"><span class="pre">de</span></tt>.</p>
</li>
<li><p class="first">Only languages listed in the <a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGES"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGES</span></tt></a> setting can be selected.
If you want to restrict the language selection to a subset of provided
languages (because your application doesn’t provide all those languages),
set <a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGES"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGES</span></tt></a> to a list of languages. For example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">LANGUAGES</span> <span class="o">=</span> <span class="p">(</span>
<span class="p">(</span><span class="s">'de'</span><span class="p">,</span> <span class="n">_</span><span class="p">(</span><span class="s">'German'</span><span class="p">)),</span>
<span class="p">(</span><span class="s">'en'</span><span class="p">,</span> <span class="n">_</span><span class="p">(</span><span class="s">'English'</span><span class="p">)),</span>
<span class="p">)</span>
</pre></div>
</div>
<p>This example restricts languages that are available for automatic
selection to German and English (and any sublanguage, like de-ch or
en-us).</p>
</li>
<li><p class="first">If you define a custom <a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGES"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGES</span></tt></a> setting, as explained in the
previous bullet, it’s OK to mark the languages as translation strings
– but use a “dummy” <tt class="docutils literal"><span class="pre">ugettext()</span></tt> function, not the one in
<tt class="docutils literal"><span class="pre">django.utils.translation</span></tt>. You should <em>never</em> import
<tt class="docutils literal"><span class="pre">django.utils.translation</span></tt> from within your settings file, because that
module in itself depends on the settings, and that would cause a circular
import.</p>
<p>The solution is to use a “dummy” <tt class="docutils literal"><span class="pre">ugettext()</span></tt> function. Here’s a sample
settings file:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="n">ugettext</span> <span class="o">=</span> <span class="k">lambda</span> <span class="n">s</span><span class="p">:</span> <span class="n">s</span>
<span class="n">LANGUAGES</span> <span class="o">=</span> <span class="p">(</span>
<span class="p">(</span><span class="s">'de'</span><span class="p">,</span> <span class="n">ugettext</span><span class="p">(</span><span class="s">'German'</span><span class="p">)),</span>
<span class="p">(</span><span class="s">'en'</span><span class="p">,</span> <span class="n">ugettext</span><span class="p">(</span><span class="s">'English'</span><span class="p">)),</span>
<span class="p">)</span>
</pre></div>
</div>
<p>With this arrangement, <a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">makemessages</span></tt></a>
will still find and mark these strings for translation, but the translation
won’t happen at runtime – so you’ll have to remember to wrap the languages in
the <em>real</em> <tt class="docutils literal"><span class="pre">ugettext()</span></tt> in any code that uses <a class="reference internal" href="../../ref/settings.html#std:setting-LANGUAGES"><tt class="xref std std-setting docutils literal"><span class="pre">LANGUAGES</span></tt></a> at
runtime.</p>
</li>
<li><p class="first">The <tt class="docutils literal"><span class="pre">LocaleMiddleware</span></tt> can only select languages for which there is a
Django-provided base translation. If you want to provide translations
for your application that aren’t already in the set of translations
in Django’s source tree, you’ll want to provide at least a basic
one as described in the <a class="reference internal" href="#locale-restrictions"><em>Locale restrictions</em></a>
note.</p>
</li>
</ul>
<p>Once <tt class="docutils literal"><span class="pre">LocaleMiddleware</span></tt> determines the user’s preference, it makes this
preference available as <tt class="docutils literal"><span class="pre">request.LANGUAGE_CODE</span></tt> for each
<a class="reference internal" href="../../ref/request-response.html#django.http.HttpRequest" title="django.http.HttpRequest"><tt class="xref py py-class docutils literal"><span class="pre">HttpRequest</span></tt></a>. Feel free to read this value in your view
code. Here’s a simple example:</p>
<div class="highlight-python"><div class="highlight"><pre><span class="k">def</span> <span class="nf">hello_world</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="n">count</span><span class="p">):</span>
<span class="k">if</span> <span class="n">request</span><span class="o">.</span><span class="n">LANGUAGE_CODE</span> <span class="o">==</span> <span class="s">'de-at'</span><span class="p">:</span>
<span class="k">return</span> <span class="n">HttpResponse</span><span class="p">(</span><span class="s">"You prefer to read Austrian German."</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">return</span> <span class="n">HttpResponse</span><span class="p">(</span><span class="s">"You prefer to read another language."</span><span class="p">)</span>
</pre></div>
</div>
<p>Note that, with static (middleware-less) translation, the language is in
<tt class="docutils literal"><span class="pre">settings.LANGUAGE_CODE</span></tt>, while with dynamic (middleware) translation, it’s
in <tt class="docutils literal"><span class="pre">request.LANGUAGE_CODE</span></tt>.</p>
</div>
<div class="section" id="s-how-django-discovers-translations">
<span id="s-id5"></span><span id="how-django-discovers-translations"></span><span id="id5"></span><h3>How Django discovers translations<a class="headerlink" href="#how-django-discovers-translations" title="Permalink to this headline">¶</a></h3>
<p>At runtime, Django builds an in-memory unified catalog of literals-translations.
To achieve this it looks for translations by following this algorithm regarding
the order in which it examines the different file paths to load the compiled
<a class="reference internal" href="index.html#term-message-file"><em class="xref std std-term">message files</em></a> (<tt class="docutils literal"><span class="pre">.mo</span></tt>) and the precedence of multiple
translations for the same literal:</p>
<ol class="arabic simple">
<li>The directories listed in <a class="reference internal" href="../../ref/settings.html#std:setting-LOCALE_PATHS"><tt class="xref std std-setting docutils literal"><span class="pre">LOCALE_PATHS</span></tt></a> have the highest
precedence, with the ones appearing first having higher precedence than
the ones appearing later.</li>
<li>Then, it looks for and uses if it exists a <tt class="docutils literal"><span class="pre">locale</span></tt> directory in each
of the installed apps listed in <a class="reference internal" href="../../ref/settings.html#std:setting-INSTALLED_APPS"><tt class="xref std std-setting docutils literal"><span class="pre">INSTALLED_APPS</span></tt></a>. The ones
appearing first have higher precedence than the ones appearing later.</li>
<li>Then, it looks for a <tt class="docutils literal"><span class="pre">locale</span></tt> directory in the project directory, or
more accurately, in the directory containing your settings file.</li>
<li>Finally, the Django-provided base translation in <tt class="docutils literal"><span class="pre">django/conf/locale</span></tt>
is used as a fallback.</li>
</ol>
<div class="deprecated">
<span class="title">Deprecated in Django 1.3:</span> Lookup in the <tt class="docutils literal"><span class="pre">locale</span></tt> subdirectory of the directory containing your
settings file (item 3 above) is deprecated since the 1.3 release and will be
removed in Django 1.5. You can use the <a class="reference internal" href="../../ref/settings.html#std:setting-LOCALE_PATHS"><tt class="xref std std-setting docutils literal"><span class="pre">LOCALE_PATHS</span></tt></a> setting
instead, by listing the absolute filesystem path of such <tt class="docutils literal"><span class="pre">locale</span></tt>
directory in the setting value.</div>
<div class="admonition-see-also admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last">The translations for literals included in JavaScript assets are looked up
following a similar but not identical algorithm. See the
<a class="reference internal" href="#javascript-catalog-view"><em>javascript_catalog view documentation</em></a> for
more details.</p>
</div>
<p>In all cases the name of the directory containing the translation is expected to
be named using <a class="reference internal" href="index.html#term-locale-name"><em class="xref std std-term">locale name</em></a> notation. E.g. <tt class="docutils literal"><span class="pre">de</span></tt>, <tt class="docutils literal"><span class="pre">pt_BR</span></tt>, <tt class="docutils literal"><span class="pre">es_AR</span></tt>,
etc.</p>
<p>This way, you can write applications that include their own translations, and
you can override base translations in your project path. Or, you can just build
a big project out of several apps and put all translations into one big common
message file specific to the project you are composing. The choice is yours.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">If you’re using manually configured settings, as described in
<a class="reference internal" href="../settings.html#settings-without-django-settings-module"><em>Using settings without setting DJANGO_SETTINGS_MODULE</em></a>, the <tt class="docutils literal"><span class="pre">locale</span></tt> directory in
the project directory will not be examined, since Django loses the ability
to work out the location of the project directory. (Django normally uses the
location of the settings file to determine this, and a settings file doesn’t
exist if you’re manually configuring your settings.)</p>
</div>
<p>All message file repositories are structured the same way. They are:</p>
<ul class="simple">
<li>All paths listed in <a class="reference internal" href="../../ref/settings.html#std:setting-LOCALE_PATHS"><tt class="xref std std-setting docutils literal"><span class="pre">LOCALE_PATHS</span></tt></a> in your settings file are
searched for <tt class="docutils literal"><span class="pre"><language>/LC_MESSAGES/django.(po|mo)</span></tt></li>
<li><tt class="docutils literal"><span class="pre">$PROJECTPATH/locale/<language>/LC_MESSAGES/django.(po|mo)</span></tt> –
deprecated, see above.</li>
<li><tt class="docutils literal"><span class="pre">$APPPATH/locale/<language>/LC_MESSAGES/django.(po|mo)</span></tt></li>
<li><tt class="docutils literal"><span class="pre">$PYTHONPATH/django/conf/locale/<language>/LC_MESSAGES/django.(po|mo)</span></tt></li>
</ul>
<p>To create message files, you use the <a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">makemessages</span></tt></a>
tool. You only need to be in the same directory where the <tt class="docutils literal"><span class="pre">locale/</span></tt> directory
is located. And you use <a class="reference internal" href="../../ref/django-admin.html#django-admin-compilemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">compilemessages</span></tt></a>
to produce the binary <tt class="docutils literal"><span class="pre">.mo</span></tt> files that are used by <tt class="docutils literal"><span class="pre">gettext</span></tt>.</p>
<p>You can also run <a class="reference internal" href="../../ref/django-admin.html#django-admin-compilemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">compilemessages</span>
<span class="pre">--settings=path.to.settings</span></tt></a> to make the compiler process all
the directories in your <a class="reference internal" href="../../ref/settings.html#std:setting-LOCALE_PATHS"><tt class="xref std std-setting docutils literal"><span class="pre">LOCALE_PATHS</span></tt></a> setting.</p>
<p>Finally, you should give some thought to the structure of your translation
files. If your applications need to be delivered to other users and will be used
in other projects, you might want to use app-specific translations. But using
app-specific translations and project-specific translations could produce weird
problems with <a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">makemessages</span></tt></a>: it will traverse all directories below
the current path and so might put message IDs into a unified, common message
file for the current project that are already in application message files.</p>
<p>The easiest way out is to store applications that are not part of the project
(and so carry their own translations) outside the project tree. That way,
<a class="reference internal" href="../../ref/django-admin.html#django-admin-makemessages"><tt class="xref std std-djadmin docutils literal"><span class="pre">django-admin.py</span> <span class="pre">makemessages</span></tt></a>, when ran on a project
level will only extract strings that are connected to your explicit project and
not strings that are distributed independently.</p>
</div>
</div>
</div>
</div>
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<h3><a href="../../contents.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Translation</a><ul>
<li><a class="reference internal" href="#overview">Overview</a></li>
<li><a class="reference internal" href="#internationalization-in-python-code">Internationalization: in Python code</a><ul>
<li><a class="reference internal" href="#standard-translation">Standard translation</a></li>
<li><a class="reference internal" href="#comments-for-translators">Comments for translators</a></li>
<li><a class="reference internal" href="#marking-strings-as-no-op">Marking strings as no-op</a></li>
<li><a class="reference internal" href="#pluralization">Pluralization</a></li>
<li><a class="reference internal" href="#contextual-markers">Contextual markers</a></li>
<li><a class="reference internal" href="#lazy-translation">Lazy translation</a><ul>
<li><a class="reference internal" href="#model-fields-and-relationships-verbose-name-and-help-text-option-values">Model fields and relationships <tt class="docutils literal"><span class="pre">verbose_name</span></tt> and <tt class="docutils literal"><span class="pre">help_text</span></tt> option values</a></li>
<li><a class="reference internal" href="#model-verbose-names-values">Model verbose names values</a></li>
<li><a class="reference internal" href="#model-methods-short-description-attribute-values">Model methods <tt class="docutils literal"><span class="pre">short_description</span></tt> attribute values</a></li>
</ul>
</li>
<li><a class="reference internal" href="#working-with-lazy-translation-objects">Working with lazy translation objects</a><ul>
<li><a class="reference internal" href="#joining-strings-string-concat">Joining strings: string_concat()</a></li>
</ul>
</li>
<li><a class="reference internal" href="#localized-names-of-languages">Localized names of languages</a></li>
</ul>
</li>
<li><a class="reference internal" href="#internationalization-in-template-code">Internationalization: in template code</a><ul>
<li><a class="reference internal" href="#trans-template-tag"><tt class="docutils literal"><span class="pre">trans</span></tt> template tag</a></li>
<li><a class="reference internal" href="#blocktrans-template-tag"><tt class="docutils literal"><span class="pre">blocktrans</span></tt> template tag</a></li>
<li><a class="reference internal" href="#other-tags">Other tags</a></li>
</ul>
</li>
<li><a class="reference internal" href="#internationalization-in-javascript-code">Internationalization: in JavaScript code</a><ul>
<li><a class="reference internal" href="#module-django.views.i18n">The <tt class="docutils literal"><span class="pre">javascript_catalog</span></tt> view</a></li>
<li><a class="reference internal" href="#using-the-javascript-translation-catalog">Using the JavaScript translation catalog</a></li>
</ul>
</li>
<li><a class="reference internal" href="#internationalization-in-url-patterns">Internationalization: in URL patterns</a><ul>
<li><a class="reference internal" href="#language-prefix-in-url-patterns">Language prefix in URL patterns</a></li>
<li><a class="reference internal" href="#translating-url-patterns">Translating URL patterns</a></li>
<li><a class="reference internal" href="#std:templatetag-language">Reversing in templates</a></li>
</ul>
</li>
<li><a class="reference internal" href="#localization-how-to-create-language-files">Localization: how to create language files</a><ul>
<li><a class="reference internal" href="#message-files">Message files</a></li>
<li><a class="reference internal" href="#compiling-message-files">Compiling message files</a></li>
<li><a class="reference internal" href="#creating-message-files-from-javascript-source-code">Creating message files from JavaScript source code</a></li>
<li><a class="reference internal" href="#gettext-on-windows"><tt class="docutils literal"><span class="pre">gettext</span></tt> on Windows</a></li>
</ul>
</li>
<li><a class="reference internal" href="#miscellaneous">Miscellaneous</a><ul>
<li><a class="reference internal" href="#the-set-language-redirect-view">The <tt class="docutils literal"><span class="pre">set_language</span></tt> redirect view</a></li>
<li><a class="reference internal" href="#using-translations-outside-views-and-templates">Using translations outside views and templates</a></li>
</ul>
</li>
<li><a class="reference internal" href="#implementation-notes">Implementation notes</a><ul>
<li><a class="reference internal" href="#specialties-of-django-translation">Specialties of Django translation</a></li>
<li><a class="reference internal" href="#how-django-discovers-language-preference">How Django discovers language preference</a></li>
<li><a class="reference internal" href="#how-django-discovers-translations">How Django discovers translations</a></li>
</ul>
</li>
</ul>
</li>
</ul>
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