sessionhandlerinterface.xml

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<!-- $Revision$ -->
<reference xml:id="class.sessionhandlerinterface" role="class" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xi="http://www.w3.org/2001/XInclude">

 <title>The SessionHandlerInterface class</title>
 <titleabbrev>SessionHandlerInterface</titleabbrev>

 <partintro>

<!-- {{{ SessionHandlerInterface intro -->
  <section xml:id="sessionhandlerinterface.intro">
   &reftitle.intro;
   <para>
    <classname>SessionHandlerInterface</classname> is an interface which defines the minimal
    prototype for creating a custom session handler. In order to pass a custom
    session handler to <function>session_set_save_handler</function> using its
    <abbrev>OOP</abbrev> invocation, the class can implement this interface.
   </para>
   <para>
    Please note the callback methods of this class are designed to be called internally by
    PHP and are not meant to be called from user-space code.
   </para>
  </section>
<!-- }}} -->

  <section xml:id="sessionhandlerinterface.synopsis">
   &reftitle.interfacesynopsis;

<!-- {{{ Synopsis -->
   <classsynopsis class="interface">
    <oointerface>
     <interfacename>SessionHandlerInterface</interfacename>
    </oointerface>

    <classsynopsisinfo role="comment">&Methods;</classsynopsisinfo>
    <xi:include xpointer="xmlns(db=http://docbook.org/ns/docbook) xpointer(id('class.sessionhandlerinterface')/db:refentry/db:refsect1[@role='description']/descendant::db:methodsynopsis[@role='SessionHandlerInterface'])">
     <xi:fallback/>
    </xi:include>
   </classsynopsis>
<!-- }}} -->

  </section>

  <section xml:id="sessionhandlerinterface.examples">
   &reftitle.examples;
   <example>
    <title>
     Example using <classname>SessionHandlerInterface</classname>
    </title>
    <para>
     The following example provides file based session storage similar to the
     PHP sessions default save handler <parameter>files</parameter>.  This
     example could easily be extended to cover database storage using your
     favorite PHP supported database engine.
    </para>
    <para>
     Note we use the OOP prototype with <function>session_set_save_handler</function> and
     register the shutdown function using the function's parameter flag.  This is generally
     advised when registering objects as session save handlers.
    </para>
    <caution>
     <para>
      For brevity, this example omits input validation. However, the
      <literal>$id</literal> parameters are actually user supplied values which
      require proper validation/sanitization to avoid vulnerabilities, such as
      path traversal issues. <emphasis>So do not use this example unmodified in
      production environments.</emphasis>
     </para>
    </caution>
    <programlisting role="php">
<![CDATA[
<?php
class MySessionHandler implements SessionHandlerInterface
{
    private $savePath;

    public function open($savePath, $sessionName): bool
    {
        $this->savePath = $savePath;
        if (!is_dir($this->savePath)) {
            mkdir($this->savePath, 0777);
        }

        return true;
    }

    public function close(): bool
    {
        return true;
    }

    #[\ReturnTypeWillChange]
    public function read($id)
    {
        return (string) @file_get_contents("$this->savePath/sess_$id");
    }

    public function write($id, $data): bool
    {
        return file_put_contents("$this->savePath/sess_$id", $data) === false ? false : true;
    }

    public function destroy($id): bool
    {
        $file = "$this->savePath/sess_$id";
        if (file_exists($file)) {
            unlink($file);
        }

        return true;
    }

    #[\ReturnTypeWillChange]
    public function gc($maxlifetime)
    {
        foreach (glob("$this->savePath/sess_*") as $file) {
            if (filemtime($file) + $maxlifetime < time() && file_exists($file)) {
                unlink($file);
            }
        }

        return true;
    }
}

$handler = new MySessionHandler();
session_set_save_handler($handler, true);
session_start();

// proceed to set and retrieve values by key from $_SESSION
]]>
    </programlisting>
   </example>
  </section>

 </partintro>

 &reference.session.entities.sessionhandlerinterface;

</reference>
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