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<title>Installing a proxy</title>
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</div><hr /><div id="mysqlnd-uh.quickstart.proxy-installation" class="section">
<h2 class="title">Installing a proxy</h2>
<p class="para">
The extension provides two built-in classes: <a href="class.mysqlnduhconnection.html" class="classname">MysqlndUhConnection</a>
and <a href="class.mysqlnduhpreparedstatement.html" class="classname">MysqlndUhPreparedStatement</a>. The classes are used
for hooking <em>mysqlnd</em> library calls. Their methods correspond
to <em>mysqlnd</em> internal functions. By default they act like
a transparent proxy and do nothing but call their <em>mysqlnd</em> counterparts.
By subclassing the classes you can install your own proxy to monitor <em>mysqlnd</em>.
</p>
<p class="para">
See also the <a href="mysqlnd-uh.quickstart.how-it-works.html" class="link">How it works</a>
guide to learn about the inner workings of this extension.
</p>
<p class="para">
Connection proxies are objects of the type <a href="class.mysqlnduhconnection.html" class="classname">MysqlndUhConnection</a>.
Connection proxy objects are installed by
<span class="function"><a href="function.mysqlnd-uh-set-connection-proxy.html" class="function">mysqlnd_uh_set_connection_proxy()</a></span>.
If you install the built-in class <a href="class.mysqlnduhconnection.html" class="classname">MysqlndUhConnection</a>
as a proxy, nothing happens. It behaves like a transparent proxy.
</p>
<p class="para">
<div class="example" id="example-1873">
<p><strong>Example #1 Proxy registration, mysqlnd_uh.enable=1</strong></p>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />mysqlnd_uh_set_connection_proxy</span><span style="color: #007700">(new </span><span style="color: #0000BB">MysqlndUhConnection</span><span style="color: #007700">());<br /></span><span style="color: #0000BB">$mysqli </span><span style="color: #007700">= new </span><span style="color: #0000BB">mysqli</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">, </span><span style="color: #DD0000">"root"</span><span style="color: #007700">, </span><span style="color: #DD0000">""</span><span style="color: #007700">, </span><span style="color: #DD0000">"test"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?></span>
</span>
</code></div>
</div>
</div>
</p>
<p class="para">
The <em>PHP_INI_SYSTEM</em> configuration setting
<em><a href="mysqlnd-uh.configuration.html#ini.mysqlnd-uh.enable" class="link">mysqlnd_uh.enable</a></em>
controls whether a proxy may be set. If disabled, the extension
will throw errors of type <em>E_WARNING</em>
</p>
<p class="para">
<div class="example" id="example-1874">
<p><strong>Example #2 Proxy installation disabled</strong></p>
<div class="example-contents">
<div class="inicode"><pre class="inicode">mysqlnd_uh.enable=0</pre>
</div>
</div>
<div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB"><?php<br />mysqlnd_uh_set_connection_proxy</span><span style="color: #007700">(new </span><span style="color: #0000BB">MysqlndUhConnection</span><span style="color: #007700">());<br /></span><span style="color: #0000BB">$mysqli </span><span style="color: #007700">= new </span><span style="color: #0000BB">mysqli</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">, </span><span style="color: #DD0000">"root"</span><span style="color: #007700">, </span><span style="color: #DD0000">""</span><span style="color: #007700">, </span><span style="color: #DD0000">"test"</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>
PHP Warning: MysqlndUhConnection::__construct(): (Mysqlnd User Handler) The plugin has been disabled by setting the configuration parameter mysqlnd_uh.enabled = false. You must not use any of the base classes in %s on line %d
PHP Warning: mysqlnd_uh_set_connection_proxy(): (Mysqlnd User Handler) The plugin has been disabled by setting the configuration parameter mysqlnd_uh.enable = false. The proxy has not been installed in %s on line %d
</pre></div>
</div>
</div>
</p>
<p class="para">
To monitor <em>mysqlnd</em>, you have to write your own
proxy object subclassing <a href="class.mysqlnduhconnection.html" class="classname">MysqlndUhConnection</a>.
Please, see the function reference for a the list of methods that
can be subclassed. Alternatively, you can use reflection to inspect
the built-in <a href="class.mysqlnduhconnection.html" class="classname">MysqlndUhConnection</a>.
</p>
<p class="para">
Create a new class <em>proxy</em>. Derive it from the
built-in class <a href="class.mysqlnduhconnection.html" class="classname">MysqlndUhConnection</a>.
Replace the
<span class="function"><a href="mysqlnduhconnection.connect.html" class="function">MysqlndUhConnection::connect()</a></span>.
method. Print out the host parameter value passed to the method.
Make sure that you call the parent implementation of the <em>connect</em>
method. Failing to do so may give unexpected and undesired results, including
memory leaks and crashes.
</p>
<p class="para">
Register your proxy and open three connections using the PHP MySQL
extensions <a href="ref.mysqli.html" class="link">mysqli</a>,
<a href="ref.mysql.html" class="link">mysql</a>,
<a href="ref.pdo-mysql.html" class="link">PDO_MYSQL</a>. If the extensions have been
compiled to use the <em>mysqlnd</em> library, the
<em>proxy::connect</em> method will be called three times, once
for each connection opened.
</p>
<p class="para">
<div class="example" id="example-1875">
<p><strong>Example #3 Connection proxy</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">proxy </span><span style="color: #007700">extends </span><span style="color: #0000BB">MysqlndUhConnection </span><span style="color: #007700">{<br /> public function </span><span style="color: #0000BB">connect</span><span style="color: #007700">(</span><span style="color: #0000BB">$res</span><span style="color: #007700">, </span><span style="color: #0000BB">$host</span><span style="color: #007700">, </span><span style="color: #0000BB">$user</span><span style="color: #007700">, </span><span style="color: #0000BB">$passwd</span><span style="color: #007700">, </span><span style="color: #0000BB">$db</span><span style="color: #007700">, </span><span style="color: #0000BB">$port</span><span style="color: #007700">, </span><span style="color: #0000BB">$socket</span><span style="color: #007700">, </span><span style="color: #0000BB">$mysql_flags</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"Connection opened to '%s'\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">$host</span><span style="color: #007700">);<br /> </span><span style="color: #FF8000">/* Always call the parent implementation! */<br /> </span><span style="color: #007700">return </span><span style="color: #0000BB">parent</span><span style="color: #007700">::</span><span style="color: #0000BB">connect</span><span style="color: #007700">(</span><span style="color: #0000BB">$res</span><span style="color: #007700">, </span><span style="color: #0000BB">$host</span><span style="color: #007700">, </span><span style="color: #0000BB">$user</span><span style="color: #007700">, </span><span style="color: #0000BB">$passwd</span><span style="color: #007700">, </span><span style="color: #0000BB">$db</span><span style="color: #007700">, </span><span style="color: #0000BB">$port</span><span style="color: #007700">, </span><span style="color: #0000BB">$socket</span><span style="color: #007700">, </span><span style="color: #0000BB">$mysql_flags</span><span style="color: #007700">);<br /> }<br />}<br /></span><span style="color: #0000BB">mysqlnd_uh_set_connection_proxy</span><span style="color: #007700">(new </span><span style="color: #0000BB">proxy</span><span style="color: #007700">());<br /><br /></span><span style="color: #0000BB">$mysqli </span><span style="color: #007700">= new </span><span style="color: #0000BB">mysqli</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">, </span><span style="color: #DD0000">"root"</span><span style="color: #007700">, </span><span style="color: #DD0000">""</span><span style="color: #007700">, </span><span style="color: #DD0000">"test"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$mysql </span><span style="color: #007700">= </span><span style="color: #0000BB">mysql_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">, </span><span style="color: #DD0000">"root"</span><span style="color: #007700">, </span><span style="color: #DD0000">""</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$pdo </span><span style="color: #007700">= new </span><span style="color: #0000BB">PDO</span><span style="color: #007700">(</span><span style="color: #DD0000">"mysql:host=localhost;dbname=test"</span><span style="color: #007700">, </span><span style="color: #DD0000">"root"</span><span style="color: #007700">, </span><span style="color: #DD0000">""</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>
Connection opened to 'localhost'
Connection opened to 'localhost'
Connection opened to 'localhost'
</pre></div>
</div>
</div>
</p>
<p class="para">
The use of prepared statement proxies follows the same pattern: create a
proxy object of the type <a href="class.mysqlnduhpreparedstatement.html" class="classname">MysqlndUhPreparedStatement</a>
and install the proxy using
<span class="function"><a href="function.mysqlnd-uh-set-statement-proxy.html" class="function">mysqlnd_uh_set_statement_proxy()</a></span>.
</p>
<p class="para">
<div class="example" id="example-1876">
<p><strong>Example #4 Prepared statement proxy</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">stmt_proxy </span><span style="color: #007700">extends </span><span style="color: #0000BB">MysqlndUhPreparedStatement </span><span style="color: #007700">{<br /> public function </span><span style="color: #0000BB">prepare</span><span style="color: #007700">(</span><span style="color: #0000BB">$res</span><span style="color: #007700">, </span><span style="color: #0000BB">$query</span><span style="color: #007700">) {<br /> </span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"%s(%s)\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">__METHOD__</span><span style="color: #007700">, </span><span style="color: #0000BB">$query</span><span style="color: #007700">);<br /> return </span><span style="color: #0000BB">parent</span><span style="color: #007700">::</span><span style="color: #0000BB">prepare</span><span style="color: #007700">(</span><span style="color: #0000BB">$res</span><span style="color: #007700">, </span><span style="color: #0000BB">$query</span><span style="color: #007700">);<br /> }<br />}<br /></span><span style="color: #0000BB">mysqlnd_uh_set_statement_proxy</span><span style="color: #007700">(new </span><span style="color: #0000BB">stmt_proxy</span><span style="color: #007700">());<br /><br /></span><span style="color: #0000BB">$mysqli </span><span style="color: #007700">= new </span><span style="color: #0000BB">mysqli</span><span style="color: #007700">(</span><span style="color: #DD0000">"localhost"</span><span style="color: #007700">, </span><span style="color: #DD0000">"root"</span><span style="color: #007700">, </span><span style="color: #DD0000">""</span><span style="color: #007700">, </span><span style="color: #DD0000">"test"</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$stmt </span><span style="color: #007700">= </span><span style="color: #0000BB">$mysqli</span><span style="color: #007700">-></span><span style="color: #0000BB">prepare</span><span style="color: #007700">(</span><span style="color: #DD0000">"SELECT 'mysqlnd hacking made easy' AS _msg FROM DUAL"</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>
stmt_proxy::prepare(SELECT 'mysqlnd hacking made easy' AS _msg FROM DUAL)
</pre></div>
</div>
</div>
</p>
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