Use a session with namespaces

In this example, we create and destroy sessions with namespaces.

Components used in this example

• Zend_Session
• Zend_Session_Namespace

---

MySession MyNamespace MyHtml Entry point HTML | Try it | View source code

Implementation of a session

class MySession
{

Processing the session

• We get the namespace, the action, the write lock, the expiration, the number of hops, and the option to regenerate the session.
• If the user requests the page without a session, we simply display the page.
• Otherwise, we start a session.
• We regenerate the session identifier if requested.
• Then we start or we stop or we simply use the session with a given namespace.
• If we catch an exception, we return the error message.

    public function process()
    {
        // We get the namespace, the action, the write lock, the expiration,
        // the number of hops, and the option to regenerate the session.
        list($namespace, $action, $lock, $expire, $hops, $regenerate) =
            $this->_getParameters();

        try {

            if ($namespace == 'none') {
                // If the user requests the page without a session,
                // we simply display the page.
                $result = 'You requested this page without a session.';

            } else {
                // Otherwise, we start a session.
                Zend_Session::start();
                // We regenerate the session identifier if requested.
                $regenerate and Zend_Session::regenerateId();

                // Then we start or we stop or we simply use the session with a given namespace.
                switch($action) {
                    case 'Start':
                        $result = $this->_start($namespace, $expire, $hops);
                        break;

                    case 'Stop':
                        $result = $this->_stop($namespace);
                        break;

                    case 'Use':
                    default:
                        $result = $this->_use($namespace, $expire, $hops, $lock);
                        break;
                }
             }

        } catch (Exception $e) {
            // If we catch an exception, we return the error message.
            $result = $e->getMessage();
        }

        return array($namespace, $result);
    }

Extraction of the parameters from the GET request

    private function _getParameters()
    {
        $namespace = isset($_GET['namespace'])? $_GET['namespace'] : 'Default';
        $action = isset($_GET['action'])? $_GET['action'] : null;
        $lock = !empty($_GET['lock']);
        $expire = isset($_GET['expire'])? $_GET['expire'] : null;
        $hops = isset($_GET['hops'])? $_GET['hops'] : null;
        $regenerate = !empty($_GET['regenerate']);

        return array($namespace, $action, $lock, $expire, $hops, $regenerate);
    }

Starting a namespace session

• We initialize the namespace if needed.
• And we update the namespace.
• We return the data for that namespace.

    private function _start($namespace, $expire, $hops)
    {
        $session = new MyNamespace($namespace);
        // We initialize the namespace if needed.
        Zend_Session::namespaceIsset($namespace) or $session->create();
        // And we update the namespace.
        $session->update($expire, $hops);
        // We return the data for that namespace.
        return $session->get();
    }

Stopping a namespace session

• We remove the namespace if the namespace exists.

    private function _stop($namespace)
    {
        $session = new MyNamespace($namespace);

        if (Zend_Session::namespaceIsset($namespace)) {
            // We remove the namespace if the namespace exists.
            $session->remove();
            $result = "Session \"$namespace\" destroyed!";

        } else {
            $result = "There is no such session: \"$namespace\"!";
        }

        return $result;
    }

Using a namespace session

• We lock the name space if requested.
• We update the namespace.
• We return the data for that namespace.

    private function _use($namespace, $expire, $hops, $lock)
    {
        if (Zend_Session::namespaceIsset($namespace)) {
            $session = new MyNamespace($namespace);

            // We lock the name space if requested.
            $lock and $session->lock();
            // We update the namespace.
            $session->update($expire, $hops);
            // We return the data for that namespace.
            $result = $session->get();
        } else {
            $result = "Please start the session: \"$namespace\"!";
        }

        return $result;
    }

}

Implementation of a custom namespace

class MyNamespace extends Zend_Session_Namespace
{

Creation of the namespace

• We reset the page load counter.
• We add the start time.
• We add te user IP address.

    public function create()
    {
        // We reset the page load counter.
        $this->page_loads = 0;
        // We add the start time.
        $this->start_time = date(DATE_RFC822);
        // We add te user IP address.
        $this->your_ip = $_SERVER['REMOTE_ADDR'];
    }

Updating the namespace

• We set the expiration time if requested.
• We set the number of hops before the namespace expires if requested.
• We update the last access time.
• We increment the counter of page loads.

    public function update($expire, $hops)
    {
        // We set the expiration time if requested.
        $expire and $this->setExpirationSeconds($expire);
        // We set the number of hops before the namespace expires if requested.
        $hops and $this->setExpirationHops($hops);
        // We update the last access time.
        $this->last_access = date(DATE_RFC822);
        // We increment the counter of page loads.
        $this->page_loads++;
    }

Removing the namespace

    public function remove()
    {
        Zend_Session::namespaceUnset($this->getNamespace());
    }

Getting the namespace data

    public function get()
    {
        return array(
            'session_id' => Zend_Session::getId(),
            'namespace' => $this->getNamespace(),
            'parameters' => $this->getIterator(),
        );
    }

Getting the name of the namespace (absent from ZF 1.9.5)

    public function getNamespace()
    {
        return $this->_namespace;
    }

}

Displaying items

class MyHtml
{

Displaying the title of the page based on the file name.

    public static function printTitle()
    {
        $basename = basename(__FILE__, '.php');
        $title = ucwords(str_replace('-' , ' ', $basename));
        $zfVersion = Zend_Version::VERSION;
        $phpVersion = phpversion();
        echo "ZfEx $title (ZF/$zfVersion PHP/$phpVersion)";
    }

Displaying the selected option

    public static function printSelected($value, $target)
    {
        $value == $target and print 'selected="selected"';
    }

Colorization of data

• We export the data as valid PHP code.
• We add the PHP tag, we colorize the code, we remove the PHP tag.
• We display the data.

    public static function colorize($mixed)
    {
        // We export the data as valid PHP code.
        $mixed = var_export($mixed, true);
        // We add the PHP tag, we colorize the code, we remove the PHP tag.
        $mixed = '<?' . "php $mixed";
        $mixed = highlight_string($mixed, true);
        $mixed = str_replace('&lt;?php&nbsp;', '', $mixed);
        // We display the data.
        echo "<pre>$mixed</pre>";
    }

}

Processing the session

• We process the session, and we get the name of the namespace and the result, to display in the form.

// We process the session, and we get the name of the namespace and the result,
// to display in the form.
$session = new MySession();
list($namespace, $result) = $session->process();

<html xmlns="http://www.w3.org/1999/xhtml">
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title><?php MyHtml::printTitle();?></title>
    <style type="text/css">
      body, td {
          font-family: arial, sans-serif;
          font-size: 0.9em;
      }
    </style>
  </head>

  <body>

    <p>EXAMPLE <?php MyHtml::printTitle();?></p>
    <hr />

    <form name="form">

      <table>

        <tr>
          <td>Namespace</td>
          <td>
            <select name="namespace">
              <optgroup label="Session">
                <option <?php MyHtml::printSelected($namespace, 'Default');?>>Default</option>
                <option <?php MyHtml::printSelected($namespace, 'One');?>>One</option>
                <option <?php MyHtml::printSelected($namespace, 'Two');?>>Two</option>
                <option <?php MyHtml::printSelected($namespace, 'Three');?>>Three</option>
              </optgroup>
              <option value="none"
                      <?php MyHtml::printSelected($namespace, 'none');?>>No Session</option>
            </select>
          </td>
        </tr>

        <tr>
          <td>Action</td>
          <td>
            <select name="action">
              <option>Use</option>
              <option>Start</option>
              <option>Stop</option>
            </select>
          </td>
        </tr>

        <tr>
          <td>Expire (sec)</td>
          <td>
            <select name="expire">
              <option></option>
              <option>1</option>
              <option >10</option>
            </select>
          </td>
        </tr>

        <tr>
          <td>Expire (hops)</td>
          <td>
            <select name="hops">
              <option></option>
              <option value="1">1</option>
              <option value="10">10</option>
            </select>
          </td>
          <td>
            (Note: Expiration after a number of hops does not seem to work properly
            with ZF 1.9.5!)
          </td>
        </tr>

        <tr>
          <td>Write Lock</td>
          <td>
            <select name="lock">
              <option value="0">Off</option>
              <option value="1">On</option>
            </select>
          </td>
          <td>Ignored on session start or destroy</td>
        </tr>

        <tr><td>&nbsp;</td></tr>

        <tr>
          <td></td>
          <td>
            <input type="submit" value="Submit" />
            <br /> <br />
            <a href="?namespace=<?php echo $namespace;?>&regenerate=1">Regenerate session</a>
          </td>
        </tr>

      </table>
    </form>

    <hr />
    RESULT
    <?php MyHtml::colorize($result);?>

  </body>
</html>