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<title>Generate URL-encoded query string</title>
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<h1 class="refname">http_build_query</h1>
<p class="verinfo">(PHP 5)</p><p class="refpurpose"><span class="refname">http_build_query</span> — <span class="dc-title">Generate URL-encoded query string</span></p>
</div>
<div class="refsect1 description" id="refsect1-function.http-build-query-description">
<h3 class="title">Description</h3>
<div class="methodsynopsis dc-description">
<span class="type">string</span> <span class="methodname"><strong>http_build_query</strong></span>
( <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <code class="parameter">$query_data</code></span>
[, <span class="methodparam"><span class="type">string</span> <code class="parameter">$numeric_prefix</code></span>
[, <span class="methodparam"><span class="type">string</span> <code class="parameter">$arg_separator</code></span>
[, <span class="methodparam"><span class="type">int</span> <code class="parameter">$enc_type</code><span class="initializer"> = <strong><code>PHP_QUERY_RFC1738</code></strong></span></span>
]]] )</div>
<p class="para rdfs-comment">
Generates a URL-encoded query string from the associative (or indexed)
array provided.
</p>
</div>
<div class="refsect1 parameters" id="refsect1-function.http-build-query-parameters">
<h3 class="title">Parameters</h3>
<p class="para">
<dl>
<dt>
<span class="term"><em><code class="parameter">query_data</code></em></span>
<dd>
<p class="para">
May be an array or object containing properties.
</p>
<p class="para">
If <em><code class="parameter">query_data</code></em> is an array, it may be a simple
one-dimensional structure, or an array of arrays (which in
turn may contain other arrays).
</p>
<p class="para">
If <em><code class="parameter">query_data</code></em> is an object, then only public
properties will be incorporated into the result.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">numeric_prefix</code></em></span>
<dd>
<p class="para">
If numeric indices are used in the base array and this parameter is
provided, it will be prepended to the numeric index for elements in
the base array only.
</p>
<p class="para">
This is meant to allow for legal variable names when the data is
decoded by PHP or another CGI application later on.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">arg_separator</code></em></span>
<dd>
<p class="para">
<a href="ini.core.html#ini.arg-separator.output" class="link">arg_separator.output</a>
is used to separate arguments, unless this parameter is specified,
and is then used.
</p>
</dd>
</dt>
<dt>
<span class="term"><em><code class="parameter">enc_type</code></em></span>
<dd>
<p class="para">
By default, <strong><code>PHP_QUERY_RFC1738</code></strong>.
</p>
<p class="para">
If <em><code class="parameter">enc_type</code></em> is
<strong><code>PHP_QUERY_RFC1738</code></strong>, then encoding is performed per
<a href="http://www.faqs.org/rfcs/rfc1738" class="link external">» RFC 1738</a> and the
<em>application/x-www-form-urlencoded</em> media type, which
implies that spaces are encoded as plus (<em>+</em>) signs.
</p>
<p class="para">
If <em><code class="parameter">enc_type</code></em> is
<strong><code>PHP_QUERY_RFC3986</code></strong>, then encoding is performed
according to <a href="http://www.faqs.org/rfcs/rfc3986" class="link external">» RFC 3986</a>, and
spaces will be percent encoded (<em>%20</em>).
</p>
</dd>
</dt>
</dl>
</p>
</div>
<div class="refsect1 returnvalues" id="refsect1-function.http-build-query-returnvalues">
<h3 class="title">Return Values</h3>
<p class="para">
Returns a URL-encoded string.
</p>
</div>
<div class="refsect1 changelog" id="refsect1-function.http-build-query-changelog">
<h3 class="title">Changelog</h3>
<p class="para">
<table class="doctable informaltable">
<thead>
<tr>
<th>Version</th>
<th>Description</th>
</tr>
</thead>
<tbody class="tbody">
<tr>
<td>5.4.0</td>
<td>
The <em><code class="parameter">enc_type</code></em> parameter was added.
</td>
</tr>
<tr>
<td>5.1.3</td>
<td>
Square brackets are escaped.
</td>
</tr>
<tr>
<td>5.1.2</td>
<td>
The <em><code class="parameter">arg_separator</code></em> parameter was added.
</td>
</tr>
</tbody>
</table>
</p>
</div>
<div class="refsect1 examples" id="refsect1-function.http-build-query-examples">
<h3 class="title">Examples</h3>
<div class="example" id="example-4085">
<p><strong>Example #1 Simple usage of <span class="function"><strong>http_build_query()</strong></span></strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$data </span><span style="color: #007700">= array(</span><span style="color: #DD0000">'foo'</span><span style="color: #007700">=></span><span style="color: #DD0000">'bar'</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'baz'</span><span style="color: #007700">=></span><span style="color: #DD0000">'boom'</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'cow'</span><span style="color: #007700">=></span><span style="color: #DD0000">'milk'</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'php'</span><span style="color: #007700">=></span><span style="color: #DD0000">'hypertext processor'</span><span style="color: #007700">);<br /><br />echo </span><span style="color: #0000BB">http_build_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #0000BB">http_build_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">, </span><span style="color: #DD0000">''</span><span style="color: #007700">, </span><span style="color: #DD0000">'&amp;'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
foo=bar&baz=boom&cow=milk&php=hypertext+processor
foo=bar&amp;baz=boom&amp;cow=milk&amp;php=hypertext+processor
</pre></div>
</div>
</div>
<div class="example" id="example-4086">
<p><strong>Example #2 <span class="function"><strong>http_build_query()</strong></span> with numerically index elements.</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$data </span><span style="color: #007700">= array(</span><span style="color: #DD0000">'foo'</span><span style="color: #007700">, </span><span style="color: #DD0000">'bar'</span><span style="color: #007700">, </span><span style="color: #DD0000">'baz'</span><span style="color: #007700">, </span><span style="color: #DD0000">'boom'</span><span style="color: #007700">, </span><span style="color: #DD0000">'cow' </span><span style="color: #007700">=> </span><span style="color: #DD0000">'milk'</span><span style="color: #007700">, </span><span style="color: #DD0000">'php' </span><span style="color: #007700">=></span><span style="color: #DD0000">'hypertext processor'</span><span style="color: #007700">);<br /><br />echo </span><span style="color: #0000BB">http_build_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">) . </span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo </span><span style="color: #0000BB">http_build_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">, </span><span style="color: #DD0000">'myvar_'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
0=foo&1=bar&2=baz&3=boom&cow=milk&php=hypertext+processor
myvar_0=foo&myvar_1=bar&myvar_2=baz&myvar_3=boom&cow=milk&php=hypertext+processor
</pre></div>
</div>
</div>
<div class="example" id="example-4087">
<p><strong>Example #3 <span class="function"><strong>http_build_query()</strong></span> with complex arrays</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />$data </span><span style="color: #007700">= array(</span><span style="color: #DD0000">'user'</span><span style="color: #007700">=>array(</span><span style="color: #DD0000">'name'</span><span style="color: #007700">=></span><span style="color: #DD0000">'Bob Smith'</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'age'</span><span style="color: #007700">=></span><span style="color: #0000BB">47</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'sex'</span><span style="color: #007700">=></span><span style="color: #DD0000">'M'</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'dob'</span><span style="color: #007700">=></span><span style="color: #DD0000">'5/12/1956'</span><span style="color: #007700">),<br /> </span><span style="color: #DD0000">'pastimes'</span><span style="color: #007700">=>array(</span><span style="color: #DD0000">'golf'</span><span style="color: #007700">, </span><span style="color: #DD0000">'opera'</span><span style="color: #007700">, </span><span style="color: #DD0000">'poker'</span><span style="color: #007700">, </span><span style="color: #DD0000">'rap'</span><span style="color: #007700">),<br /> </span><span style="color: #DD0000">'children'</span><span style="color: #007700">=>array(</span><span style="color: #DD0000">'bobby'</span><span style="color: #007700">=>array(</span><span style="color: #DD0000">'age'</span><span style="color: #007700">=></span><span style="color: #0000BB">12</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'sex'</span><span style="color: #007700">=></span><span style="color: #DD0000">'M'</span><span style="color: #007700">),<br /> </span><span style="color: #DD0000">'sally'</span><span style="color: #007700">=>array(</span><span style="color: #DD0000">'age'</span><span style="color: #007700">=></span><span style="color: #0000BB">8</span><span style="color: #007700">,<br /> </span><span style="color: #DD0000">'sex'</span><span style="color: #007700">=></span><span style="color: #DD0000">'F'</span><span style="color: #007700">)),<br /> </span><span style="color: #DD0000">'CEO'</span><span style="color: #007700">);<br /><br />echo </span><span style="color: #0000BB">http_build_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$data</span><span style="color: #007700">, </span><span style="color: #DD0000">'flags_'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>
this will output : (word wrapped for readability)
</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
user%5Bname%5D=Bob+Smith&user%5Bage%5D=47&user%5Bsex%5D=M&
user%5Bdob%5D=5%2F12%2F1956&pastimes%5B0%5D=golf&pastimes%5B1%5D=opera&
pastimes%5B2%5D=poker&pastimes%5B3%5D=rap&children%5Bbobby%5D%5Bage%5D=12&
children%5Bbobby%5D%5Bsex%5D=M&children%5Bsally%5D%5Bage%5D=8&
children%5Bsally%5D%5Bsex%5D=F&flags_0=CEO
</pre></div>
</div>
<div class="example-contents"><p>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
Only the numerically indexed element in the base array "CEO" received a
prefix. The other numeric indices, found under pastimes, do not
require a string prefix to be legal variable names.
</p>
</p></blockquote>
</p></div>
</div>
<div class="example" id="example-4088">
<p><strong>Example #4 Using <span class="function"><strong>http_build_query()</strong></span> with an object</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /></span><span style="color: #007700">class </span><span style="color: #0000BB">parentClass </span><span style="color: #007700">{<br /> public </span><span style="color: #0000BB">$pub </span><span style="color: #007700">= </span><span style="color: #DD0000">'publicParent'</span><span style="color: #007700">;<br /> protected </span><span style="color: #0000BB">$prot </span><span style="color: #007700">= </span><span style="color: #DD0000">'protectedParent'</span><span style="color: #007700">;<br /> private </span><span style="color: #0000BB">$priv </span><span style="color: #007700">= </span><span style="color: #DD0000">'privateParent'</span><span style="color: #007700">;<br /> public </span><span style="color: #0000BB">$pub_bar </span><span style="color: #007700">= </span><span style="color: #0000BB">Null</span><span style="color: #007700">;<br /> protected </span><span style="color: #0000BB">$prot_bar </span><span style="color: #007700">= </span><span style="color: #0000BB">Null</span><span style="color: #007700">;<br /> private </span><span style="color: #0000BB">$priv_bar </span><span style="color: #007700">= </span><span style="color: #0000BB">Null</span><span style="color: #007700">;<br /><br /> public function </span><span style="color: #0000BB">__construct</span><span style="color: #007700">(){<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">pub_bar </span><span style="color: #007700">= new </span><span style="color: #0000BB">childClass</span><span style="color: #007700">();<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">prot_bar </span><span style="color: #007700">= new </span><span style="color: #0000BB">childClass</span><span style="color: #007700">();<br /> </span><span style="color: #0000BB">$this</span><span style="color: #007700">-></span><span style="color: #0000BB">priv_bar </span><span style="color: #007700">= new </span><span style="color: #0000BB">childClass</span><span style="color: #007700">();<br /> }<br />}<br /><br />class </span><span style="color: #0000BB">childClass </span><span style="color: #007700">{<br /> public </span><span style="color: #0000BB">$pub </span><span style="color: #007700">= </span><span style="color: #DD0000">'publicChild'</span><span style="color: #007700">;<br /> protected </span><span style="color: #0000BB">$prot </span><span style="color: #007700">= </span><span style="color: #DD0000">'protectedChild'</span><span style="color: #007700">;<br /> private </span><span style="color: #0000BB">$priv </span><span style="color: #007700">= </span><span style="color: #DD0000">'privateChild'</span><span style="color: #007700">;<br />}<br /><br /></span><span style="color: #0000BB">$parent </span><span style="color: #007700">= new </span><span style="color: #0000BB">parentClass</span><span style="color: #007700">();<br /><br />echo </span><span style="color: #0000BB">http_build_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$parent</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
<div class="example-contents"><p>The above example will output:</p></div>
<div class="example-contents screen">
<div class="cdata"><pre>
pub=publicParent&pub_bar%5Bpub%5D=publicChild
</pre></div>
</div>
</div>
</div>
<div class="refsect1 seealso" id="refsect1-function.http-build-query-seealso">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"> <span class="function"><a href="function.parse-str.html" class="function" rel="rdfs-seeAlso">parse_str()</a> - Parses the string into variables</span></li>
<li class="member"> <span class="function"><a href="function.parse-url.html" class="function" rel="rdfs-seeAlso">parse_url()</a> - Parse a URL and return its components</span></li>
<li class="member"> <span class="function"><a href="function.urlencode.html" class="function" rel="rdfs-seeAlso">urlencode()</a> - URL-encodes string</span></li>
<li class="member"> <span class="function"><a href="function.array-walk.html" class="function" rel="rdfs-seeAlso">array_walk()</a> - Apply a user function to every member of an array</span></li>
</ul>
</p>
</div>
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