Lazy session handler for ZF2

LazySaveHandler.php

<?php

namespace Apex\Session;

use Zend\Session\SaveHandler\SaveHandlerInterface;

/**
 * Based on https://github.com/adamfranco/lazy_sessions/blob/master/lazy_sessions.php
 *
 * @author Glen
 */
class LazySaveHandler implements SaveHandlerInterface
{
    private $savePath;

    /**
     * Open Session - retrieve resources
     *
     * @param string $savePath
     * @param string $name
     */
    public function open($savePath, $name)
    {
        if ($savePath === '') {
            $savePath = sys_get_temp_dir();
        }

        $this->savePath = $savePath;

        if (!is_dir($this->savePath)) {
            mkdir($this->savePath, 0777);
        }

        return true;
    }

    /**
     * Close Session - free resources
     */
    public function close()
    {
        return true;
    }

    /**
     * Read session data
     *
     * @param string $id
     */
    public function read($id)
    {
        $file = sprintf('%s/sess_%s', $this->savePath, $id);

        // Handle the case of first time visitors and clients that don't store cookies (eg. web crawlers).
        if (!isset($_COOKIE[session_name()])) {
            return '';
        }

        if (file_exists($file) && ($data = file_get_contents($file)) !== false) {
            return $data;
        } else {
            return '';
        }
    }

    /**
     * Write Session - commit data to resource
     *
     * @param string $id
     * @param mixed $data
     */
    public function write($id, $data)
    {
        if ($data === '') {
            // Build up an array of cookie headers (excluding the session cookie).
            $cookies = array();

            foreach (headers_list() as $header) {
                if (strpos($header, 'Set-Cookie') === 0 && strpos($header, 'Set-Cookie: ' . session_name()) !== 0) {
                    $cookies[] = $header;
                }
            }

            // Remove all cookie headers.
            header_remove('Set-Cookie');

            // Add back non-session cookie headers (if any).
            foreach ($cookies as $cookie) {
                header($cookie);
            }

            return true;
        }

        $file = sprintf('%s/sess_%s', $this->savePath, $id);

        return (file_put_contents($file, $data) !== false);
    }

    /**
     * Destroy Session - remove data from resource for
     * given session id
     *
     * @param string $id
     */
    public function destroy($id)
    {
        $file = sprintf('%s/sess_%s', $this->savePath, $id);

        if (file_exists($file)) {
            unlink($file);
        }

        return true;
    }

    /**
     * Garbage Collection - remove old session data older
     * than $maxlifetime (in seconds)
     *
     * @param int $maxlifetime
     */
    public function gc($maxlifetime)
    {
        foreach (glob(sprintf('%s/sess_*', $this->savePath)) as $file) {
            if (filemtime($file) + $maxlifetime < time() && file_exists($file)) {
                unlink($file);
            }
        }

        return true;
    }
}