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<title>Autoloading Classes</title>
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</div><hr /><div id="language.oop5.autoload" class="sect1">
<h2 class="title">Autoloading Classes</h2>
<p class="para">
Many developers writing object-oriented applications create
one PHP source file per class definition. One of the biggest
annoyances is having to write a long list of needed includes
at the beginning of each script (one for each class).
</p>
<p class="para">
In PHP 5, this is no longer necessary. The
<span class="function"><a href="function.spl-autoload-register.html" class="function">spl_autoload_register()</a></span> function registers any number of
autoloaders, enabling for classes and interfaces to be automatically loaded
if they are currently not defined. By registering autoloaders, PHP is given
a last chance to load the class or interface before it fails with an error.
</p>
<div class="tip"><strong class="tip">Tip</strong>
<p class="para">
Although the <span class="function"><a href="function.autoload.html" class="function">__autoload()</a></span> function can also be used for
autoloading classes and interfaces, it's preferred to use the
<span class="function"><a href="function.spl-autoload-register.html" class="function">spl_autoload_register()</a></span> function. This is because it is
a more flexible alternative (enabling for any number of autoloaders to be
specified in the application, such as in third party libraries). For this
reason, using <span class="function"><a href="function.autoload.html" class="function">__autoload()</a></span> is discouraged and it may be
deprecated in the future.
</p>
</div>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
Prior to PHP 5.3, exceptions thrown in the <span class="function"><a href="function.autoload.html" class="function">__autoload()</a></span>
function could not be caught in the
<a href="language.exceptions.html" class="link">catch</a> block and would result in
a fatal error. From PHP 5.3 and upwards, this is possible provided that if
a custom exception is thrown, then the custom exception class is available.
The <span class="function"><a href="function.autoload.html" class="function">__autoload()</a></span> function may be used recursively to
autoload the custom exception class.
</p>
</p></blockquote>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
Autoloading is not available if using PHP in CLI
<a href="features.commandline.html" class="link">interactive mode</a>.
</p>
</p></blockquote>
<blockquote class="note"><p><strong class="note">Note</strong>:
<p class="para">
If the class name is used e.g. in <span class="function"><a href="function.call-user-func.html" class="function">call_user_func()</a></span> then
it can contain some dangerous characters such as <em>../</em>.
It is recommended to not use the user-input in such functions or at least
verify the input in <span class="function"><a href="function.autoload.html" class="function">__autoload()</a></span>.
</p>
</p></blockquote>
<p class="para">
<div class="example" id="example-187">
<p><strong>Example #1 Autoload example</strong></p>
<div class="example-contents"><p>
This example attempts to load the classes <em>MyClass1</em>
and <em>MyClass2</em> from the files <var class="filename">MyClass1.php</var>
and <var class="filename">MyClass2.php</var> respectively.
</p></div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />spl_autoload_register</span><span style="color: #007700">(function (</span><span style="color: #0000BB">$class_name</span><span style="color: #007700">) {<br /> include </span><span style="color: #0000BB">$class_name </span><span style="color: #007700">. </span><span style="color: #DD0000">'.php'</span><span style="color: #007700">;<br />});<br /><br /></span><span style="color: #0000BB">$obj </span><span style="color: #007700">= new </span><span style="color: #0000BB">MyClass1</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">$obj2 </span><span style="color: #007700">= new </span><span style="color: #0000BB">MyClass2</span><span style="color: #007700">(); <br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<div class="example" id="example-188">
<p><strong>Example #2 Autoload other example</strong></p>
<div class="example-contents"><p>
This example attempts to load the interface <em>ITest</em>.
</p></div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br /><br />spl_autoload_register</span><span style="color: #007700">(function (</span><span style="color: #0000BB">$name</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$name</span><span style="color: #007700">);<br />});<br /><br />class </span><span style="color: #0000BB">Foo </span><span style="color: #007700">implements </span><span style="color: #0000BB">ITest </span><span style="color: #007700">{<br />}<br /><br /></span><span style="color: #FF8000">/*<br />string(5) "ITest"<br /><br />Fatal error: Interface 'ITest' not found in ...<br />*/<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
<div class="example" id="example-189">
<p><strong>Example #3 Autoloading with exception handling for 5.3.0+</strong></p>
<div class="example-contents"><p>
This example throws an exception and demonstrates the try/catch block.
</p></div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />spl_autoload_register</span><span style="color: #007700">(function (</span><span style="color: #0000BB">$name</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"Want to load </span><span style="color: #0000BB">$name</span><span style="color: #DD0000">.\n"</span><span style="color: #007700">;<br /> throw new </span><span style="color: #0000BB">Exception</span><span style="color: #007700">(</span><span style="color: #DD0000">"Unable to load </span><span style="color: #0000BB">$name</span><span style="color: #DD0000">."</span><span style="color: #007700">);<br />});<br /><br />try {<br /> </span><span style="color: #0000BB">$obj </span><span style="color: #007700">= new </span><span style="color: #0000BB">NonLoadableClass</span><span style="color: #007700">();<br />} catch (</span><span style="color: #0000BB">Exception $e</span><span style="color: #007700">) {<br /> echo </span><span style="color: #0000BB">$e</span><span style="color: #007700">-></span><span style="color: #0000BB">getMessage</span><span style="color: #007700">(), </span><span style="color: #DD0000">"\n"</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>
Want to load NonLoadableClass.
Unable to load NonLoadableClass.
</pre></div>
</div>
</div>
<div class="example" id="example-190">
<p><strong>Example #4 Autoloading with exception handling for 5.3.0+ - Missing custom exception</strong></p>
<div class="example-contents"><p>
This example throws an exception for a non-loadable, custom exception.
</p></div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />spl_autoload_register</span><span style="color: #007700">(function (</span><span style="color: #0000BB">$name</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"Want to load </span><span style="color: #0000BB">$name</span><span style="color: #DD0000">.\n"</span><span style="color: #007700">;<br /> throw new </span><span style="color: #0000BB">MissingException</span><span style="color: #007700">(</span><span style="color: #DD0000">"Unable to load </span><span style="color: #0000BB">$name</span><span style="color: #DD0000">."</span><span style="color: #007700">);<br />});<br /><br />try {<br /> </span><span style="color: #0000BB">$obj </span><span style="color: #007700">= new </span><span style="color: #0000BB">NonLoadableClass</span><span style="color: #007700">();<br />} catch (</span><span style="color: #0000BB">Exception $e</span><span style="color: #007700">) {<br /> echo </span><span style="color: #0000BB">$e</span><span style="color: #007700">-></span><span style="color: #0000BB">getMessage</span><span style="color: #007700">(), </span><span style="color: #DD0000">"\n"</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>
Want to load NonLoadableClass.
Want to load MissingException.
Fatal error: Class 'MissingException' not found in testMissingException.php on line 4
</pre></div>
</div>
</div>
</p>
<div class="simplesect">
<h3 class="title">See Also</h3>
<p class="para">
<ul class="simplelist">
<li class="member"><span class="function"><a href="function.unserialize.html" class="function">unserialize()</a></span></li>
<li class="member"><a href="var.configuration.html#ini.unserialize-callback-func" class="link">unserialize_callback_func</a></li>
<li class="member"><span class="function"><a href="function.spl-autoload-register.html" class="function">spl_autoload_register()</a></span></li>
<li class="member"><span class="function"><a href="function.spl-autoload.html" class="function">spl_autoload()</a></span></li>
<li class="member"><span class="function"><a href="function.autoload.html" class="function">__autoload()</a></span></li>
</ul>
</p>
</div>
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