<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" lang=""> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Signals — Django 1.8.19 documentation</title> <link rel="stylesheet" href="../_static/default.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../', VERSION: '1.8.19', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <link rel="index" title="Index" href="../genindex.html" /> <link rel="search" title="Search" href="../search.html" /> <link rel="top" title="Django 1.8.19 documentation" href="../contents.html" /> <link rel="up" title="API Reference" href="index.html" /> <link rel="next" title="Templates" href="templates/index.html" /> <link rel="prev" title="Settings" href="settings.html" /> <script type="text/javascript" src="../templatebuiltins.js"></script> <script type="text/javascript"> (function($) { if (!django_template_builtins) { // templatebuiltins.js missing, do nothing. return; 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To prevent this, pass <code class="docutils literal"><span class="pre">weak=False</span></code> when you call the signal’s <a class="reference internal" href="../topics/signals.html#django.dispatch.Signal.connect" title="django.dispatch.Signal.connect"><code class="xref py py-meth docutils literal"><span class="pre">connect()</span></code></a>.</p> </div> <div class="versionadded"> <span class="title">New in Django 1.7:</span> <p>Model signals <code class="docutils literal"><span class="pre">sender</span></code> model can be lazily referenced when connecting a receiver by specifying its full application label. For example, an <code class="docutils literal"><span class="pre">Answer</span></code> model defined in the <code class="docutils literal"><span class="pre">polls</span></code> application could be referenced as <code class="docutils literal"><span class="pre">'polls.Answer'</span></code>. This sort of reference can be quite handy when dealing with circular import dependencies and swappable models.</p> </div> <div class="section" id="s-pre-init"> <span id="pre-init"></span><h3>pre_init<a class="headerlink" href="#pre-init" title="Permalink to this headline">¶</a></h3> <dl class="attribute"> <dt id="django.db.models.signals.pre_init"> <code class="descclassname">django.db.models.signals.</code><code class="descname">pre_init</code><a class="headerlink" href="#django.db.models.signals.pre_init" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Whenever you instantiate a Django model, this signal is sent at the beginning of the model’s <code class="docutils literal"><span class="pre">__init__()</span></code> method.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The model class that just had an instance created.</dd> <dt><code class="docutils literal"><span class="pre">args</span></code></dt> <dd>A list of positional arguments passed to <code class="docutils literal"><span class="pre">__init__()</span></code>:</dd> <dt><code class="docutils literal"><span class="pre">kwargs</span></code></dt> <dd>A dictionary of keyword arguments passed to <code class="docutils literal"><span class="pre">__init__()</span></code>:</dd> </dl> <p>For example, the <a class="reference internal" href="../intro/tutorial01.html"><span class="doc">tutorial</span></a> has this line:</p> <div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">p</span> <span class="o">=</span> <span class="n">Poll</span><span class="p">(</span><span class="n">question</span><span class="o">=</span><span class="s2">"What's up?"</span><span class="p">,</span> <span class="n">pub_date</span><span class="o">=</span><span class="n">datetime</span><span class="o">.</span><span class="n">now</span><span class="p">())</span> </pre></div> </div> <p>The arguments sent to a <a class="reference internal" href="#django.db.models.signals.pre_init" title="django.db.models.signals.pre_init"><code class="xref py py-data docutils literal"><span class="pre">pre_init</span></code></a> handler would be:</p> <table class="docutils"> <colgroup> <col width="14%" /> <col width="86%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Argument</th> <th class="head">Value</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><code class="docutils literal"><span class="pre">sender</span></code></td> <td><code class="docutils literal"><span class="pre">Poll</span></code> (the class itself)</td> </tr> <tr class="row-odd"><td><code class="docutils literal"><span class="pre">args</span></code></td> <td><code class="docutils literal"><span class="pre">[]</span></code> (an empty list because there were no positional arguments passed to <code class="docutils literal"><span class="pre">__init__()</span></code>.)</td> </tr> <tr class="row-even"><td><code class="docutils literal"><span class="pre">kwargs</span></code></td> <td><code class="docutils literal"><span class="pre">{'question':</span> <span class="pre">"What's</span> <span class="pre">up?",</span> <span class="pre">'pub_date':</span> <span class="pre">datetime.now()}</span></code></td> </tr> </tbody> </table> </div> <div class="section" id="s-post-init"> <span id="post-init"></span><h3>post_init<a class="headerlink" href="#post-init" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.models.signals.post_init"> <code class="descclassname">django.db.models.signals.</code><code class="descname">post_init</code><a class="headerlink" href="#django.db.models.signals.post_init" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Like pre_init, but this one is sent when the <code class="docutils literal"><span class="pre">__init__()</span></code> method finishes.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>As above: the model class that just had an instance created.</dd> <dt><code class="docutils literal"><span class="pre">instance</span></code></dt> <dd>The actual instance of the model that’s just been created.</dd> </dl> </div> <div class="section" id="s-pre-save"> <span id="pre-save"></span><h3>pre_save<a class="headerlink" href="#pre-save" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.models.signals.pre_save"> <code class="descclassname">django.db.models.signals.</code><code class="descname">pre_save</code><a class="headerlink" href="#django.db.models.signals.pre_save" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>This is sent at the beginning of a model’s <a class="reference internal" href="models/instances.html#django.db.models.Model.save" title="django.db.models.Model.save"><code class="xref py py-meth docutils literal"><span class="pre">save()</span></code></a> method.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The model class.</dd> <dt><code class="docutils literal"><span class="pre">instance</span></code></dt> <dd>The actual instance being saved.</dd> <dt><code class="docutils literal"><span class="pre">raw</span></code></dt> <dd>A boolean; <code class="docutils literal"><span class="pre">True</span></code> if the model is saved exactly as presented (i.e. when loading a fixture). One should not query/modify other records in the database as the database might not be in a consistent state yet.</dd> <dt><code class="docutils literal"><span class="pre">using</span></code></dt> <dd>The database alias being used.</dd> <dt><code class="docutils literal"><span class="pre">update_fields</span></code></dt> <dd>The set of fields to update explicitly specified in the <code class="docutils literal"><span class="pre">save()</span></code> method. <code class="docutils literal"><span class="pre">None</span></code> if this argument was not used in the <code class="docutils literal"><span class="pre">save()</span></code> call.</dd> </dl> </div> <div class="section" id="s-post-save"> <span id="post-save"></span><h3>post_save<a class="headerlink" href="#post-save" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.models.signals.post_save"> <code class="descclassname">django.db.models.signals.</code><code class="descname">post_save</code><a class="headerlink" href="#django.db.models.signals.post_save" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Like <a class="reference internal" href="#django.db.models.signals.pre_save" title="django.db.models.signals.pre_save"><code class="xref py py-data docutils literal"><span class="pre">pre_save</span></code></a>, but sent at the end of the <a class="reference internal" href="models/instances.html#django.db.models.Model.save" title="django.db.models.Model.save"><code class="xref py py-meth docutils literal"><span class="pre">save()</span></code></a> method.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The model class.</dd> <dt><code class="docutils literal"><span class="pre">instance</span></code></dt> <dd>The actual instance being saved.</dd> <dt><code class="docutils literal"><span class="pre">created</span></code></dt> <dd>A boolean; <code class="docutils literal"><span class="pre">True</span></code> if a new record was created.</dd> <dt><code class="docutils literal"><span class="pre">raw</span></code></dt> <dd>A boolean; <code class="docutils literal"><span class="pre">True</span></code> if the model is saved exactly as presented (i.e. when loading a fixture). One should not query/modify other records in the database as the database might not be in a consistent state yet.</dd> <dt><code class="docutils literal"><span class="pre">using</span></code></dt> <dd>The database alias being used.</dd> <dt><code class="docutils literal"><span class="pre">update_fields</span></code></dt> <dd>The set of fields to update explicitly specified in the <code class="docutils literal"><span class="pre">save()</span></code> method. <code class="docutils literal"><span class="pre">None</span></code> if this argument was not used in the <code class="docutils literal"><span class="pre">save()</span></code> call.</dd> </dl> </div> <div class="section" id="s-pre-delete"> <span id="pre-delete"></span><h3>pre_delete<a class="headerlink" href="#pre-delete" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.models.signals.pre_delete"> <code class="descclassname">django.db.models.signals.</code><code class="descname">pre_delete</code><a class="headerlink" href="#django.db.models.signals.pre_delete" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Sent at the beginning of a model’s <a class="reference internal" href="models/instances.html#django.db.models.Model.delete" title="django.db.models.Model.delete"><code class="xref py py-meth docutils literal"><span class="pre">delete()</span></code></a> method and a queryset’s <a class="reference internal" href="models/querysets.html#django.db.models.query.QuerySet.delete" title="django.db.models.query.QuerySet.delete"><code class="xref py py-meth docutils literal"><span class="pre">delete()</span></code></a> method.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The model class.</dd> <dt><code class="docutils literal"><span class="pre">instance</span></code></dt> <dd>The actual instance being deleted.</dd> <dt><code class="docutils literal"><span class="pre">using</span></code></dt> <dd>The database alias being used.</dd> </dl> </div> <div class="section" id="s-post-delete"> <span id="post-delete"></span><h3>post_delete<a class="headerlink" href="#post-delete" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.models.signals.post_delete"> <code class="descclassname">django.db.models.signals.</code><code class="descname">post_delete</code><a class="headerlink" href="#django.db.models.signals.post_delete" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Like <a class="reference internal" href="#django.db.models.signals.pre_delete" title="django.db.models.signals.pre_delete"><code class="xref py py-data docutils literal"><span class="pre">pre_delete</span></code></a>, but sent at the end of a model’s <a class="reference internal" href="models/instances.html#django.db.models.Model.delete" title="django.db.models.Model.delete"><code class="xref py py-meth docutils literal"><span class="pre">delete()</span></code></a> method and a queryset’s <a class="reference internal" href="models/querysets.html#django.db.models.query.QuerySet.delete" title="django.db.models.query.QuerySet.delete"><code class="xref py py-meth docutils literal"><span class="pre">delete()</span></code></a> method.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The model class.</dd> <dt><code class="docutils literal"><span class="pre">instance</span></code></dt> <dd><p class="first">The actual instance being deleted.</p> <p class="last">Note that the object will no longer be in the database, so be very careful what you do with this instance.</p> </dd> <dt><code class="docutils literal"><span class="pre">using</span></code></dt> <dd>The database alias being used.</dd> </dl> </div> <div class="section" id="s-m2m-changed"> <span id="m2m-changed"></span><h3>m2m_changed<a class="headerlink" href="#m2m-changed" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.models.signals.m2m_changed"> <code class="descclassname">django.db.models.signals.</code><code class="descname">m2m_changed</code><a class="headerlink" href="#django.db.models.signals.m2m_changed" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Sent when a <a class="reference internal" href="models/fields.html#django.db.models.ManyToManyField" title="django.db.models.ManyToManyField"><code class="xref py py-class docutils literal"><span class="pre">ManyToManyField</span></code></a> is changed on a model instance. Strictly speaking, this is not a model signal since it is sent by the <a class="reference internal" href="models/fields.html#django.db.models.ManyToManyField" title="django.db.models.ManyToManyField"><code class="xref py py-class docutils literal"><span class="pre">ManyToManyField</span></code></a>, but since it complements the <a class="reference internal" href="#django.db.models.signals.pre_save" title="django.db.models.signals.pre_save"><code class="xref py py-data docutils literal"><span class="pre">pre_save</span></code></a>/<a class="reference internal" href="#django.db.models.signals.post_save" title="django.db.models.signals.post_save"><code class="xref py py-data docutils literal"><span class="pre">post_save</span></code></a> and <a class="reference internal" href="#django.db.models.signals.pre_delete" title="django.db.models.signals.pre_delete"><code class="xref py py-data docutils literal"><span class="pre">pre_delete</span></code></a>/<a class="reference internal" href="#django.db.models.signals.post_delete" title="django.db.models.signals.post_delete"><code class="xref py py-data docutils literal"><span class="pre">post_delete</span></code></a> when it comes to tracking changes to models, it is included here.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The intermediate model class describing the <a class="reference internal" href="models/fields.html#django.db.models.ManyToManyField" title="django.db.models.ManyToManyField"><code class="xref py py-class docutils literal"><span class="pre">ManyToManyField</span></code></a>. This class is automatically created when a many-to-many field is defined; you can access it using the <code class="docutils literal"><span class="pre">through</span></code> attribute on the many-to-many field.</dd> <dt><code class="docutils literal"><span class="pre">instance</span></code></dt> <dd>The instance whose many-to-many relation is updated. This can be an instance of the <code class="docutils literal"><span class="pre">sender</span></code>, or of the class the <a class="reference internal" href="models/fields.html#django.db.models.ManyToManyField" title="django.db.models.ManyToManyField"><code class="xref py py-class docutils literal"><span class="pre">ManyToManyField</span></code></a> is related to.</dd> <dt><code class="docutils literal"><span class="pre">action</span></code></dt> <dd><p class="first">A string indicating the type of update that is done on the relation. This can be one of the following:</p> <dl class="last docutils"> <dt><code class="docutils literal"><span class="pre">"pre_add"</span></code></dt> <dd>Sent <em>before</em> one or more objects are added to the relation.</dd> <dt><code class="docutils literal"><span class="pre">"post_add"</span></code></dt> <dd>Sent <em>after</em> one or more objects are added to the relation.</dd> <dt><code class="docutils literal"><span class="pre">"pre_remove"</span></code></dt> <dd>Sent <em>before</em> one or more objects are removed from the relation.</dd> <dt><code class="docutils literal"><span class="pre">"post_remove"</span></code></dt> <dd>Sent <em>after</em> one or more objects are removed from the relation.</dd> <dt><code class="docutils literal"><span class="pre">"pre_clear"</span></code></dt> <dd>Sent <em>before</em> the relation is cleared.</dd> <dt><code class="docutils literal"><span class="pre">"post_clear"</span></code></dt> <dd>Sent <em>after</em> the relation is cleared.</dd> </dl> </dd> <dt><code class="docutils literal"><span class="pre">reverse</span></code></dt> <dd>Indicates which side of the relation is updated (i.e., if it is the forward or reverse relation that is being modified).</dd> <dt><code class="docutils literal"><span class="pre">model</span></code></dt> <dd>The class of the objects that are added to, removed from or cleared from the relation.</dd> <dt><code class="docutils literal"><span class="pre">pk_set</span></code></dt> <dd><p class="first">For the <code class="docutils literal"><span class="pre">pre_add</span></code>, <code class="docutils literal"><span class="pre">post_add</span></code>, <code class="docutils literal"><span class="pre">pre_remove</span></code> and <code class="docutils literal"><span class="pre">post_remove</span></code> actions, this is a set of primary key values that have been added to or removed from the relation.</p> <p class="last">For the <code class="docutils literal"><span class="pre">pre_clear</span></code> and <code class="docutils literal"><span class="pre">post_clear</span></code> actions, this is <code class="docutils literal"><span class="pre">None</span></code>.</p> </dd> <dt><code class="docutils literal"><span class="pre">using</span></code></dt> <dd>The database alias being used.</dd> </dl> <p>For example, if a <code class="docutils literal"><span class="pre">Pizza</span></code> can have multiple <code class="docutils literal"><span class="pre">Topping</span></code> objects, modeled like this:</p> <div class="highlight-default"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">Topping</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="c1"># ...</span> <span class="k">pass</span> <span class="k">class</span> <span class="nc">Pizza</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="c1"># ...</span> <span class="n">toppings</span> <span class="o">=</span> <span class="n">models</span><span class="o">.</span><span class="n">ManyToManyField</span><span class="p">(</span><span class="n">Topping</span><span class="p">)</span> </pre></div> </div> <p>If we connected a handler like this:</p> <div class="highlight-default"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">django.db.models.signals</span> <span class="k">import</span> <span class="n">m2m_changed</span> <span class="k">def</span> <span class="nf">toppings_changed</span><span class="p">(</span><span class="n">sender</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span> <span class="c1"># Do something</span> <span class="k">pass</span> <span class="n">m2m_changed</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="n">toppings_changed</span><span class="p">,</span> <span class="n">sender</span><span class="o">=</span><span class="n">Pizza</span><span class="o">.</span><span class="n">toppings</span><span class="o">.</span><span class="n">through</span><span class="p">)</span> </pre></div> </div> <p>and then did something like this:</p> <div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">p</span> <span class="o">=</span> <span class="n">Pizza</span><span class="o">.</span><span class="n">objects</span><span class="o">.</span><span class="n">create</span><span class="p">(</span><span class="o">...</span><span class="p">)</span> <span class="gp">>>> </span><span class="n">t</span> <span class="o">=</span> <span class="n">Topping</span><span class="o">.</span><span class="n">objects</span><span class="o">.</span><span class="n">create</span><span class="p">(</span><span class="o">...</span><span class="p">)</span> <span class="gp">>>> </span><span class="n">p</span><span class="o">.</span><span class="n">toppings</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">t</span><span class="p">)</span> </pre></div> </div> <p>the arguments sent to a <a class="reference internal" href="#django.db.models.signals.m2m_changed" title="django.db.models.signals.m2m_changed"><code class="xref py py-data docutils literal"><span class="pre">m2m_changed</span></code></a> handler (<code class="docutils literal"><span class="pre">toppings_changed</span></code> in the example above) would be:</p> <table class="docutils"> <colgroup> <col width="18%" /> <col width="82%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Argument</th> <th class="head">Value</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><code class="docutils literal"><span class="pre">sender</span></code></td> <td><code class="docutils literal"><span class="pre">Pizza.toppings.through</span></code> (the intermediate m2m class)</td> </tr> <tr class="row-odd"><td><code class="docutils literal"><span class="pre">instance</span></code></td> <td><code class="docutils literal"><span class="pre">p</span></code> (the <code class="docutils literal"><span class="pre">Pizza</span></code> instance being modified)</td> </tr> <tr class="row-even"><td><code class="docutils literal"><span class="pre">action</span></code></td> <td><code class="docutils literal"><span class="pre">"pre_add"</span></code> (followed by a separate signal with <code class="docutils literal"><span class="pre">"post_add"</span></code>)</td> </tr> <tr class="row-odd"><td><code class="docutils literal"><span class="pre">reverse</span></code></td> <td><code class="docutils literal"><span class="pre">False</span></code> (<code class="docutils literal"><span class="pre">Pizza</span></code> contains the <a class="reference internal" href="models/fields.html#django.db.models.ManyToManyField" title="django.db.models.ManyToManyField"><code class="xref py py-class docutils literal"><span class="pre">ManyToManyField</span></code></a>, so this call modifies the forward relation)</td> </tr> <tr class="row-even"><td><code class="docutils literal"><span class="pre">model</span></code></td> <td><code class="docutils literal"><span class="pre">Topping</span></code> (the class of the objects added to the <code class="docutils literal"><span class="pre">Pizza</span></code>)</td> </tr> <tr class="row-odd"><td><code class="docutils literal"><span class="pre">pk_set</span></code></td> <td><code class="docutils literal"><span class="pre">{t.id}</span></code> (since only <code class="docutils literal"><span class="pre">Topping</span> <span class="pre">t</span></code> was added to the relation)</td> </tr> <tr class="row-even"><td><code class="docutils literal"><span class="pre">using</span></code></td> <td><code class="docutils literal"><span class="pre">"default"</span></code> (since the default router sends writes here)</td> </tr> </tbody> </table> <p>And if we would then do something like this:</p> <div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">t</span><span class="o">.</span><span class="n">pizza_set</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="n">p</span><span class="p">)</span> </pre></div> </div> <p>the arguments sent to a <a class="reference internal" href="#django.db.models.signals.m2m_changed" title="django.db.models.signals.m2m_changed"><code class="xref py py-data docutils literal"><span class="pre">m2m_changed</span></code></a> handler would be:</p> <table class="docutils"> <colgroup> <col width="16%" /> <col width="84%" /> </colgroup> <thead valign="bottom"> <tr class="row-odd"><th class="head">Argument</th> <th class="head">Value</th> </tr> </thead> <tbody valign="top"> <tr class="row-even"><td><code class="docutils literal"><span class="pre">sender</span></code></td> <td><code class="docutils literal"><span class="pre">Pizza.toppings.through</span></code> (the intermediate m2m class)</td> </tr> <tr class="row-odd"><td><code class="docutils literal"><span class="pre">instance</span></code></td> <td><code class="docutils literal"><span class="pre">t</span></code> (the <code class="docutils literal"><span class="pre">Topping</span></code> instance being modified)</td> </tr> <tr class="row-even"><td><code class="docutils literal"><span class="pre">action</span></code></td> <td><code class="docutils literal"><span class="pre">"pre_remove"</span></code> (followed by a separate signal with <code class="docutils literal"><span class="pre">"post_remove"</span></code>)</td> </tr> <tr class="row-odd"><td><code class="docutils literal"><span class="pre">reverse</span></code></td> <td><code class="docutils literal"><span class="pre">True</span></code> (<code class="docutils literal"><span class="pre">Pizza</span></code> contains the <a class="reference internal" href="models/fields.html#django.db.models.ManyToManyField" title="django.db.models.ManyToManyField"><code class="xref py py-class docutils literal"><span class="pre">ManyToManyField</span></code></a>, so this call modifies the reverse relation)</td> </tr> <tr class="row-even"><td><code class="docutils literal"><span class="pre">model</span></code></td> <td><code class="docutils literal"><span class="pre">Pizza</span></code> (the class of the objects removed from the <code class="docutils literal"><span class="pre">Topping</span></code>)</td> </tr> <tr class="row-odd"><td><code class="docutils literal"><span class="pre">pk_set</span></code></td> <td><code class="docutils literal"><span class="pre">{p.id}</span></code> (since only <code class="docutils literal"><span class="pre">Pizza</span> <span class="pre">p</span></code> was removed from the relation)</td> </tr> <tr class="row-even"><td><code class="docutils literal"><span class="pre">using</span></code></td> <td><code class="docutils literal"><span class="pre">"default"</span></code> (since the default router sends writes here)</td> </tr> </tbody> </table> </div> <div class="section" id="s-class-prepared"> <span id="class-prepared"></span><h3>class_prepared<a class="headerlink" href="#class-prepared" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.models.signals.class_prepared"> <code class="descclassname">django.db.models.signals.</code><code class="descname">class_prepared</code><a class="headerlink" href="#django.db.models.signals.class_prepared" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Sent whenever a model class has been “prepared” – that is, once model has been defined and registered with Django’s model system. Django uses this signal internally; it’s not generally used in third-party applications.</p> <p>Since this signal is sent during the app registry population process, and <a class="reference internal" href="applications.html#django.apps.AppConfig.ready" title="django.apps.AppConfig.ready"><code class="xref py py-meth docutils literal"><span class="pre">AppConfig.ready()</span></code></a> runs after the app registry is fully populated, receivers cannot be connected in that method. One possibility is to connect them <code class="docutils literal"><span class="pre">AppConfig.__init__()</span></code> instead, taking care not to import models or trigger calls to the app registry.</p> <p>Arguments that are sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The model class which was just prepared.</dd> </dl> </div> </div> <div class="section" id="s-management-signals"> <span id="management-signals"></span><h2>Management signals<a class="headerlink" href="#management-signals" title="Permalink to this headline">¶</a></h2> <p>Signals sent by <a class="reference internal" href="django-admin.html"><span class="doc">django-admin</span></a>.</p> <div class="section" id="s-pre-migrate"> <span id="pre-migrate"></span><h3>pre_migrate<a class="headerlink" href="#pre-migrate" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.models.signals.pre_migrate"> <code class="descclassname">django.db.models.signals.</code><code class="descname">pre_migrate</code><a class="headerlink" href="#django.db.models.signals.pre_migrate" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Sent by the <a class="reference internal" href="django-admin.html#django-admin-migrate"><code class="xref std std-djadmin docutils literal"><span class="pre">migrate</span></code></a> command before it starts to install an application. It’s not emitted for applications that lack a <code class="docutils literal"><span class="pre">models</span></code> module.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>An <a class="reference internal" href="applications.html#django.apps.AppConfig" title="django.apps.AppConfig"><code class="xref py py-class docutils literal"><span class="pre">AppConfig</span></code></a> instance for the application about to be migrated/synced.</dd> <dt><code class="docutils literal"><span class="pre">app_config</span></code></dt> <dd>Same as <code class="docutils literal"><span class="pre">sender</span></code>.</dd> <dt><code class="docutils literal"><span class="pre">verbosity</span></code></dt> <dd><p class="first">Indicates how much information manage.py is printing on screen. See the <a class="reference internal" href="django-admin.html#django-admin-option---verbosity"><code class="xref std std-djadminopt docutils literal"><span class="pre">--verbosity</span></code></a> flag for details.</p> <p class="last">Functions which listen for <a class="reference internal" href="#django.db.models.signals.pre_migrate" title="django.db.models.signals.pre_migrate"><code class="xref py py-data docutils literal"><span class="pre">pre_migrate</span></code></a> should adjust what they output to the screen based on the value of this argument.</p> </dd> <dt><code class="docutils literal"><span class="pre">interactive</span></code></dt> <dd><p class="first">If <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">True</span></code>, it’s safe to prompt the user to input things on the command line. If <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">False</span></code>, functions which listen for this signal should not try to prompt for anything.</p> <p class="last">For example, the <a class="reference internal" href="../topics/auth/index.html#module-django.contrib.auth" title="django.contrib.auth: Django's authentication framework."><code class="xref py py-mod docutils literal"><span class="pre">django.contrib.auth</span></code></a> app only prompts to create a superuser when <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">True</span></code>.</p> </dd> <dt><code class="docutils literal"><span class="pre">using</span></code></dt> <dd>The alias of database on which a command will operate.</dd> </dl> </div> <div class="section" id="s-pre-syncdb"> <span id="pre-syncdb"></span><h3>pre_syncdb<a class="headerlink" href="#pre-syncdb" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.models.signals.pre_syncdb"> <code class="descclassname">django.db.models.signals.</code><code class="descname">pre_syncdb</code><a class="headerlink" href="#django.db.models.signals.pre_syncdb" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <div class="deprecated"> <p><span class="versionmodified">Deprecated since version 1.7: </span>This signal has been replaced by <a class="reference internal" href="#django.db.models.signals.pre_migrate" title="django.db.models.signals.pre_migrate"><code class="xref py py-data docutils literal"><span class="pre">pre_migrate</span></code></a>.</p> </div> <p>Sent by the <a class="reference internal" href="django-admin.html#django-admin-syncdb"><code class="xref std std-djadmin docutils literal"><span class="pre">syncdb</span></code></a> command before it starts to install an application.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The <code class="docutils literal"><span class="pre">models</span></code> module that was just installed. That is, if <a class="reference internal" href="django-admin.html#django-admin-syncdb"><code class="xref std std-djadmin docutils literal"><span class="pre">syncdb</span></code></a> just installed an app called <code class="docutils literal"><span class="pre">"foo.bar.myapp"</span></code>, <code class="docutils literal"><span class="pre">sender</span></code> will be the <code class="docutils literal"><span class="pre">foo.bar.myapp.models</span></code> module.</dd> <dt><code class="docutils literal"><span class="pre">app</span></code></dt> <dd>Same as <code class="docutils literal"><span class="pre">sender</span></code>.</dd> <dt><code class="docutils literal"><span class="pre">create_models</span></code></dt> <dd>A list of the model classes from any app which <a class="reference internal" href="django-admin.html#django-admin-syncdb"><code class="xref std std-djadmin docutils literal"><span class="pre">syncdb</span></code></a> plans to create.</dd> <dt><code class="docutils literal"><span class="pre">verbosity</span></code></dt> <dd><p class="first">Indicates how much information manage.py is printing on screen. See the <a class="reference internal" href="django-admin.html#django-admin-option---verbosity"><code class="xref std std-djadminopt docutils literal"><span class="pre">--verbosity</span></code></a> flag for details.</p> <p class="last">Functions which listen for <a class="reference internal" href="#django.db.models.signals.pre_syncdb" title="django.db.models.signals.pre_syncdb"><code class="xref py py-data docutils literal"><span class="pre">pre_syncdb</span></code></a> should adjust what they output to the screen based on the value of this argument.</p> </dd> <dt><code class="docutils literal"><span class="pre">interactive</span></code></dt> <dd><p class="first">If <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">True</span></code>, it’s safe to prompt the user to input things on the command line. If <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">False</span></code>, functions which listen for this signal should not try to prompt for anything.</p> <p class="last">For example, the <a class="reference internal" href="../topics/auth/index.html#module-django.contrib.auth" title="django.contrib.auth: Django's authentication framework."><code class="xref py py-mod docutils literal"><span class="pre">django.contrib.auth</span></code></a> app only prompts to create a superuser when <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">True</span></code>.</p> </dd> <dt><code class="docutils literal"><span class="pre">db</span></code></dt> <dd>The alias of database on which a command will operate.</dd> </dl> </div> <div class="section" id="s-post-migrate"> <span id="post-migrate"></span><h3>post_migrate<a class="headerlink" href="#post-migrate" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.models.signals.post_migrate"> <code class="descclassname">django.db.models.signals.</code><code class="descname">post_migrate</code><a class="headerlink" href="#django.db.models.signals.post_migrate" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Sent by the <a class="reference internal" href="django-admin.html#django-admin-migrate"><code class="xref std std-djadmin docutils literal"><span class="pre">migrate</span></code></a> command after it installs an application, and the <a class="reference internal" href="django-admin.html#django-admin-flush"><code class="xref std std-djadmin docutils literal"><span class="pre">flush</span></code></a> command. It’s not emitted for applications that lack a <code class="docutils literal"><span class="pre">models</span></code> module.</p> <p>It is important that handlers of this signal perform idempotent changes (e.g. no database alterations) as this may cause the <a class="reference internal" href="django-admin.html#django-admin-flush"><code class="xref std std-djadmin docutils literal"><span class="pre">flush</span></code></a> management command to fail if it also ran during the <a class="reference internal" href="django-admin.html#django-admin-migrate"><code class="xref std std-djadmin docutils literal"><span class="pre">migrate</span></code></a> command.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>An <a class="reference internal" href="applications.html#django.apps.AppConfig" title="django.apps.AppConfig"><code class="xref py py-class docutils literal"><span class="pre">AppConfig</span></code></a> instance for the application that was just installed.</dd> <dt><code class="docutils literal"><span class="pre">app_config</span></code></dt> <dd>Same as <code class="docutils literal"><span class="pre">sender</span></code>.</dd> <dt><code class="docutils literal"><span class="pre">verbosity</span></code></dt> <dd><p class="first">Indicates how much information manage.py is printing on screen. See the <a class="reference internal" href="django-admin.html#django-admin-option---verbosity"><code class="xref std std-djadminopt docutils literal"><span class="pre">--verbosity</span></code></a> flag for details.</p> <p class="last">Functions which listen for <a class="reference internal" href="#django.db.models.signals.post_migrate" title="django.db.models.signals.post_migrate"><code class="xref py py-data docutils literal"><span class="pre">post_migrate</span></code></a> should adjust what they output to the screen based on the value of this argument.</p> </dd> <dt><code class="docutils literal"><span class="pre">interactive</span></code></dt> <dd><p class="first">If <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">True</span></code>, it’s safe to prompt the user to input things on the command line. If <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">False</span></code>, functions which listen for this signal should not try to prompt for anything.</p> <p class="last">For example, the <a class="reference internal" href="../topics/auth/index.html#module-django.contrib.auth" title="django.contrib.auth: Django's authentication framework."><code class="xref py py-mod docutils literal"><span class="pre">django.contrib.auth</span></code></a> app only prompts to create a superuser when <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">True</span></code>.</p> </dd> <dt><code class="docutils literal"><span class="pre">using</span></code></dt> <dd>The database alias used for synchronization. Defaults to the <code class="docutils literal"><span class="pre">default</span></code> database.</dd> </dl> <p>For example, you could register a callback in an <a class="reference internal" href="applications.html#django.apps.AppConfig" title="django.apps.AppConfig"><code class="xref py py-class docutils literal"><span class="pre">AppConfig</span></code></a> like this:</p> <div class="highlight-default"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">django.apps</span> <span class="k">import</span> <span class="n">AppConfig</span> <span class="kn">from</span> <span class="nn">django.db.models.signals</span> <span class="k">import</span> <span class="n">post_migrate</span> <span class="k">def</span> <span class="nf">my_callback</span><span class="p">(</span><span class="n">sender</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span> <span class="c1"># Your specific logic here</span> <span class="k">pass</span> <span class="k">class</span> <span class="nc">MyAppConfig</span><span class="p">(</span><span class="n">AppConfig</span><span class="p">):</span> <span class="o">...</span> <span class="k">def</span> <span class="nf">ready</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="n">post_migrate</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="n">my_callback</span><span class="p">,</span> <span class="n">sender</span><span class="o">=</span><span class="bp">self</span><span class="p">)</span> </pre></div> </div> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">If you provide an <a class="reference internal" href="applications.html#django.apps.AppConfig" title="django.apps.AppConfig"><code class="xref py py-class docutils literal"><span class="pre">AppConfig</span></code></a> instance as the sender argument, please ensure that the signal is registered in <a class="reference internal" href="applications.html#django.apps.AppConfig.ready" title="django.apps.AppConfig.ready"><code class="xref py py-meth docutils literal"><span class="pre">ready()</span></code></a>. <code class="docutils literal"><span class="pre">AppConfig</span></code>s are recreated for tests that run with a modified set of <a class="reference internal" href="settings.html#std:setting-INSTALLED_APPS"><code class="xref std std-setting docutils literal"><span class="pre">INSTALLED_APPS</span></code></a> (such as when settings are overridden) and such signals should be connected for each new <code class="docutils literal"><span class="pre">AppConfig</span></code> instance.</p> </div> </div> <div class="section" id="s-post-syncdb"> <span id="post-syncdb"></span><h3>post_syncdb<a class="headerlink" href="#post-syncdb" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.models.signals.post_syncdb"> <code class="descclassname">django.db.models.signals.</code><code class="descname">post_syncdb</code><a class="headerlink" href="#django.db.models.signals.post_syncdb" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <div class="deprecated"> <p><span class="versionmodified">Deprecated since version 1.7: </span>This signal has been replaced by <a class="reference internal" href="#django.db.models.signals.post_migrate" title="django.db.models.signals.post_migrate"><code class="xref py py-data docutils literal"><span class="pre">post_migrate</span></code></a>.</p> </div> <p>Sent by the <a class="reference internal" href="django-admin.html#django-admin-syncdb"><code class="xref std std-djadmin docutils literal"><span class="pre">syncdb</span></code></a> command after it installs an application, and the <a class="reference internal" href="django-admin.html#django-admin-flush"><code class="xref std std-djadmin docutils literal"><span class="pre">flush</span></code></a> command.</p> <p>It is important that handlers of this signal perform idempotent changes (e.g. no database alterations) as this may cause the <a class="reference internal" href="django-admin.html#django-admin-flush"><code class="xref std std-djadmin docutils literal"><span class="pre">flush</span></code></a> management command to fail if it also ran during the <a class="reference internal" href="django-admin.html#django-admin-syncdb"><code class="xref std std-djadmin docutils literal"><span class="pre">syncdb</span></code></a> command.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The <code class="docutils literal"><span class="pre">models</span></code> module that was just installed. That is, if <a class="reference internal" href="django-admin.html#django-admin-syncdb"><code class="xref std std-djadmin docutils literal"><span class="pre">syncdb</span></code></a> just installed an app called <code class="docutils literal"><span class="pre">"foo.bar.myapp"</span></code>, <code class="docutils literal"><span class="pre">sender</span></code> will be the <code class="docutils literal"><span class="pre">foo.bar.myapp.models</span></code> module.</dd> <dt><code class="docutils literal"><span class="pre">app</span></code></dt> <dd>Same as <code class="docutils literal"><span class="pre">sender</span></code>.</dd> <dt><code class="docutils literal"><span class="pre">created_models</span></code></dt> <dd>A list of the model classes from any app which <a class="reference internal" href="django-admin.html#django-admin-syncdb"><code class="xref std std-djadmin docutils literal"><span class="pre">syncdb</span></code></a> has created so far.</dd> <dt><code class="docutils literal"><span class="pre">verbosity</span></code></dt> <dd><p class="first">Indicates how much information manage.py is printing on screen. See the <a class="reference internal" href="django-admin.html#django-admin-option---verbosity"><code class="xref std std-djadminopt docutils literal"><span class="pre">--verbosity</span></code></a> flag for details.</p> <p class="last">Functions which listen for <a class="reference internal" href="#django.db.models.signals.post_syncdb" title="django.db.models.signals.post_syncdb"><code class="xref py py-data docutils literal"><span class="pre">post_syncdb</span></code></a> should adjust what they output to the screen based on the value of this argument.</p> </dd> <dt><code class="docutils literal"><span class="pre">interactive</span></code></dt> <dd><p class="first">If <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">True</span></code>, it’s safe to prompt the user to input things on the command line. If <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">False</span></code>, functions which listen for this signal should not try to prompt for anything.</p> <p class="last">For example, the <a class="reference internal" href="../topics/auth/index.html#module-django.contrib.auth" title="django.contrib.auth: Django's authentication framework."><code class="xref py py-mod docutils literal"><span class="pre">django.contrib.auth</span></code></a> app only prompts to create a superuser when <code class="docutils literal"><span class="pre">interactive</span></code> is <code class="docutils literal"><span class="pre">True</span></code>.</p> </dd> <dt><code class="docutils literal"><span class="pre">db</span></code></dt> <dd>The database alias used for synchronization. Defaults to the <code class="docutils literal"><span class="pre">default</span></code> database.</dd> </dl> <p>For example, <code class="docutils literal"><span class="pre">yourapp/management/__init__.py</span></code> could be written like:</p> <div class="highlight-default"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">django.db.models.signals</span> <span class="k">import</span> <span class="n">post_syncdb</span> <span class="kn">import</span> <span class="nn">yourapp.models</span> <span class="k">def</span> <span class="nf">my_callback</span><span class="p">(</span><span class="n">sender</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span> <span class="c1"># Your specific logic here</span> <span class="k">pass</span> <span class="n">post_syncdb</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="n">my_callback</span><span class="p">,</span> <span class="n">sender</span><span class="o">=</span><span class="n">yourapp</span><span class="o">.</span><span class="n">models</span><span class="p">)</span> </pre></div> </div> </div> </div> <div class="section" id="s-module-django.core.signals"> <span id="s-request-response-signals"></span><span id="module-django.core.signals"></span><span id="request-response-signals"></span><h2>Request/response signals<a class="headerlink" href="#module-django.core.signals" title="Permalink to this headline">¶</a></h2> <p>Signals sent by the core framework when processing a request.</p> <div class="section" id="s-request-started"> <span id="request-started"></span><h3>request_started<a class="headerlink" href="#request-started" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.core.signals.request_started"> <code class="descclassname">django.core.signals.</code><code class="descname">request_started</code><a class="headerlink" href="#django.core.signals.request_started" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Sent when Django begins processing an HTTP request.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The handler class – e.g. <code class="docutils literal"><span class="pre">django.core.handlers.wsgi.WsgiHandler</span></code> – that handled the request.</dd> <dt><code class="docutils literal"><span class="pre">environ</span></code></dt> <dd>The <code class="docutils literal"><span class="pre">environ</span></code> dictionary provided to the request.</dd> </dl> <div class="versionchanged"> <span class="title">Changed in Django 1.8:</span> <p>The <code class="docutils literal"><span class="pre">environ</span></code> argument was added.</p> </div> </div> <div class="section" id="s-request-finished"> <span id="request-finished"></span><h3>request_finished<a class="headerlink" href="#request-finished" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.core.signals.request_finished"> <code class="descclassname">django.core.signals.</code><code class="descname">request_finished</code><a class="headerlink" href="#django.core.signals.request_finished" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Sent when Django finishes delivering an HTTP response to the client.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">Some WSGI servers and middleware do not always call <code class="docutils literal"><span class="pre">close</span></code> on the response object after handling a request, most notably uWSGI prior to 1.2.6 and Sentry’s error reporting middleware up to 2.0.7. In those cases this signal isn’t sent at all. This can result in idle connections to database and memcache servers.</p> </div> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The handler class, as above.</dd> </dl> </div> <div class="section" id="s-got-request-exception"> <span id="got-request-exception"></span><h3>got_request_exception<a class="headerlink" href="#got-request-exception" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.core.signals.got_request_exception"> <code class="descclassname">django.core.signals.</code><code class="descname">got_request_exception</code><a class="headerlink" href="#django.core.signals.got_request_exception" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>This signal is sent whenever Django encounters an exception while processing an incoming HTTP request.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The handler class, as above.</dd> <dt><code class="docutils literal"><span class="pre">request</span></code></dt> <dd>The <a class="reference internal" href="request-response.html#django.http.HttpRequest" title="django.http.HttpRequest"><code class="xref py py-class docutils literal"><span class="pre">HttpRequest</span></code></a> object.</dd> </dl> </div> </div> <div class="section" id="s-module-django.test.signals"> <span id="s-test-signals"></span><span id="module-django.test.signals"></span><span id="test-signals"></span><h2>Test signals<a class="headerlink" href="#module-django.test.signals" title="Permalink to this headline">¶</a></h2> <p>Signals only sent when <a class="reference internal" href="../topics/testing/overview.html#running-tests"><span class="std std-ref">running tests</span></a>.</p> <div class="section" id="s-setting-changed"> <span id="setting-changed"></span><h3>setting_changed<a class="headerlink" href="#setting-changed" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.test.signals.setting_changed"> <code class="descclassname">django.test.signals.</code><code class="descname">setting_changed</code><a class="headerlink" href="#django.test.signals.setting_changed" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>This signal is sent when the value of a setting is changed through the <code class="docutils literal"><span class="pre">django.test.TestCase.settings()</span></code> context manager or the <a class="reference internal" href="../topics/testing/tools.html#django.test.override_settings" title="django.test.override_settings"><code class="xref py py-func docutils literal"><span class="pre">django.test.override_settings()</span></code></a> decorator/context manager.</p> <p>It’s actually sent twice: when the new value is applied (“setup”) and when the original value is restored (“teardown”). Use the <code class="docutils literal"><span class="pre">enter</span></code> argument to distinguish between the two.</p> <p>You can also import this signal from <code class="docutils literal"><span class="pre">django.core.signals</span></code> to avoid importing from <code class="docutils literal"><span class="pre">django.test</span></code> in non-test situations.</p> <div class="versionchanged"> <span class="title">Changed in Django 1.8:</span> <p>The signal was moved to <code class="docutils literal"><span class="pre">django.core.signals</span></code> as described above.</p> </div> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The settings handler.</dd> <dt><code class="docutils literal"><span class="pre">setting</span></code></dt> <dd>The name of the setting.</dd> <dt><code class="docutils literal"><span class="pre">value</span></code></dt> <dd>The value of the setting after the change. For settings that initially don’t exist, in the “teardown” phase, <code class="docutils literal"><span class="pre">value</span></code> is <code class="docutils literal"><span class="pre">None</span></code>.</dd> <dt><code class="docutils literal"><span class="pre">enter</span></code></dt> <dd><div class="first last versionadded"> <span class="title">New in Django 1.7:</span> <p>A boolean; <code class="docutils literal"><span class="pre">True</span></code> if the setting is applied, <code class="docutils literal"><span class="pre">False</span></code> if restored.</p> </div> </dd> </dl> </div> <div class="section" id="s-template-rendered"> <span id="template-rendered"></span><h3>template_rendered<a class="headerlink" href="#template-rendered" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.test.signals.template_rendered"> <code class="descclassname">django.test.signals.</code><code class="descname">template_rendered</code><a class="headerlink" href="#django.test.signals.template_rendered" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Sent when the test system renders a template. This signal is not emitted during normal operation of a Django server – it is only available during testing.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The <a class="reference internal" href="templates/api.html#django.template.Template" title="django.template.Template"><code class="xref py py-class docutils literal"><span class="pre">Template</span></code></a> object which was rendered.</dd> <dt><code class="docutils literal"><span class="pre">template</span></code></dt> <dd>Same as sender</dd> <dt><code class="docutils literal"><span class="pre">context</span></code></dt> <dd>The <a class="reference internal" href="templates/api.html#django.template.Context" title="django.template.Context"><code class="xref py py-class docutils literal"><span class="pre">Context</span></code></a> with which the template was rendered.</dd> </dl> </div> </div> <div class="section" id="s-module-django.db.backends"> <span id="s-database-wrappers"></span><span id="module-django.db.backends"></span><span id="database-wrappers"></span><h2>Database Wrappers<a class="headerlink" href="#module-django.db.backends" title="Permalink to this headline">¶</a></h2> <p>Signals sent by the database wrapper when a database connection is initiated.</p> <div class="section" id="s-connection-created"> <span id="connection-created"></span><h3>connection_created<a class="headerlink" href="#connection-created" title="Permalink to this headline">¶</a></h3> <dl class="data"> <dt id="django.db.backends.signals.connection_created"> <code class="descclassname">django.db.backends.signals.</code><code class="descname">connection_created</code><a class="headerlink" href="#django.db.backends.signals.connection_created" title="Permalink to this definition">¶</a></dt> <dd></dd></dl> <p>Sent when the database wrapper makes the initial connection to the database. This is particularly useful if you’d like to send any post connection commands to the SQL backend.</p> <p>Arguments sent with this signal:</p> <dl class="docutils"> <dt><code class="docutils literal"><span class="pre">sender</span></code></dt> <dd>The database wrapper class – i.e. <code class="docutils literal"><span class="pre">django.db.backends.postgresql_psycopg2.DatabaseWrapper</span></code> or <code class="docutils literal"><span class="pre">django.db.backends.mysql.DatabaseWrapper</span></code>, etc.</dd> <dt><code class="docutils literal"><span class="pre">connection</span></code></dt> <dd>The database connection that was opened. This can be used in a multiple-database configuration to differentiate connection signals from different databases.</dd> </dl> </div> </div> </div> </div> </div> </div> <div class="yui-b" id="sidebar"> <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> <div class="sphinxsidebarwrapper"> <h3><a href="../contents.html">Table Of Contents</a></h3> <ul> <li><a class="reference internal" href="#">Signals</a><ul> <li><a class="reference internal" href="#module-django.db.models.signals">Model signals</a><ul> <li><a class="reference internal" href="#pre-init">pre_init</a></li> <li><a class="reference internal" href="#post-init">post_init</a></li> <li><a class="reference internal" href="#pre-save">pre_save</a></li> <li><a class="reference internal" href="#post-save">post_save</a></li> <li><a class="reference internal" href="#pre-delete">pre_delete</a></li> <li><a class="reference internal" href="#post-delete">post_delete</a></li> <li><a class="reference internal" href="#m2m-changed">m2m_changed</a></li> <li><a class="reference internal" href="#class-prepared">class_prepared</a></li> </ul> </li> <li><a class="reference internal" href="#management-signals">Management signals</a><ul> <li><a class="reference internal" href="#pre-migrate">pre_migrate</a></li> <li><a class="reference internal" href="#pre-syncdb">pre_syncdb</a></li> <li><a class="reference internal" href="#post-migrate">post_migrate</a></li> <li><a class="reference internal" href="#post-syncdb">post_syncdb</a></li> </ul> </li> <li><a class="reference internal" href="#module-django.core.signals">Request/response signals</a><ul> <li><a class="reference internal" href="#request-started">request_started</a></li> <li><a class="reference internal" href="#request-finished">request_finished</a></li> <li><a class="reference internal" href="#got-request-exception">got_request_exception</a></li> </ul> </li> <li><a class="reference internal" href="#module-django.test.signals">Test signals</a><ul> <li><a class="reference internal" href="#setting-changed">setting_changed</a></li> <li><a class="reference internal" href="#template-rendered">template_rendered</a></li> </ul> </li> <li><a class="reference internal" href="#module-django.db.backends">Database Wrappers</a><ul> <li><a class="reference internal" href="#connection-created">connection_created</a></li> </ul> </li> </ul> </li> </ul> <h3>Browse</h3> <ul> <li>Prev: <a href="settings.html">Settings</a></li> <li>Next: <a href="templates/index.html">Templates</a></li> </ul> <h3>You are here:</h3> <ul> <li> <a href="../index.html">Django 1.8.19 documentation</a> <ul><li><a href="index.html">API Reference</a> <ul><li>Signals</li></ul> </li></ul> </li> </ul> <div role="note" aria-label="source link"> <h3>This Page</h3> <ul class="this-page-menu"> <li><a href="../_sources/ref/signals.txt" rel="nofollow">Show Source</a></li> </ul> </div> <div id="searchbox" style="display: none" role="search"> <h3>Quick search</h3> <form class="search" action="../search.html" method="get"> <div><input type="text" name="q" /></div> <div><input type="submit" value="Go" /></div> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <h3>Last update:</h3> <p class="topless">Jan 06, 2019</p> </div> </div> <div id="ft"> <div class="nav"> « <a href="settings.html" title="Settings">previous</a> | <a href="index.html" title="API Reference" accesskey="U">up</a> | <a href="templates/index.html" title="Templates">next</a> »</div> </div> </div> <div class="clearer"></div> </div> </body> </html>