livephpmonitor.php

<?php
/**
 * Live.php file monitor
 * @author Bence Meszaros
 * @link http://bencemeszaros.com
 * @version 1.2
 */

namespace MBence\LivePHP;

class LivephpMonitor
{
    /** list of directories to check for changes */
    protected $dirs = array('.');
    /** ignore these files or directories */
    protected $ignore = array('');

    /** default time limit in seconds */
    protected $timeLimit = 125;
    /** Refresh css files without reloading the page */
    protected $cssOnTheFly = true;
    /** the time to die */
    protected $deadLine;

    /**
     * Constructor
     */
    public function __construct($options = array())
    {
        // check for runtime options
        if (!empty($options) && is_array($options)) {
            foreach ($options as $key => $val) {
                if (isset($this->$key)) {
                    $this->$key = $val;
                }
            }
        }

        // check that $_GET['s'] is a valid unix timestamp
        if (!empty($_GET['s']) && is_numeric($_GET['s']))
        {
            // $_GET['s'] is in millisec, but we need only seconds
            $start = (int) ($_GET['s'] / 1000);

            $this->headers();
            $this->setDeadLine();
            $this->main($start);
        }
        else
        {
            header('HTTP/1.1 400 Bad Request');
            die;
        }
    }

    /**
     * Output the no-cache headers
     */
    protected function headers()
    {
        header('Cache-Control: no-cache, must-revalidate');
        header('Expires: -1');
    }

    /**
     * Sets the time limit if possible
     */
    protected function setDeadLine()
    {
        // in safe mode there is no way to set the time limit
        if (!ini_get('safe_mode'))
        {
            set_time_limit($this->timeLimit);
        }
        // lets check what the actual limit is
        $limit = ini_get('max_execution_time');

        if (empty($limit) || $limit < 1)
        {
            // in case of unsuccesful ini_get, (or unlimited execution), we fall back to the default 30 sec
            $limit = 30;
        }
        // we stop the loop 5 sec befor the time limit, just for sure
        $this->deadLine = time() + $limit - 5;
    }

    /**
     * Main function
     * @param int $start start date in unix timestamp
     */
    protected function main($start)
    {
        // clear file status cache
        clearstatcache();
        // long polling loop
        do
        {
            // look for the changes every second until the execution time allows it.
            foreach ($this->dirs as $root)
            {
                $result = $this->checkDir(realpath($root), $start);
                if ($result)
                {
                    // if we find modified files in any of the directories, we can skip the rest
                    echo json_encode($result);

                    die;
                }
            }

            sleep(1);
        }
        while (time() < $this->deadLine);
    }

    /**
     * A fast (and non-recursive) function to check for modified files in a directory structure
     *
     * @param string $root directory path
     * @param int $start (unix timestamp) to find newer files of
     * @return bool true (or the modification time of the css file) if modified file found, false otherwise
     */
    protected function checkDir($root, $start)
    {
        $stack[] = $root;
        // walk through the stack
        while (!empty($stack))
        {
            $dir = array_shift($stack);
            $files = glob($dir . '/*');
            // make sure that we have an array (glob can return false in some cases)
            if (!empty($files) && is_array($files))
            {
                foreach ($files as $file)
                {
                    if (empty($this->ignore) || !in_array(basename($file), $this->ignore))
                    {
                        if (is_dir($file))
                        {
                            // we add the directories to the stack to check them later
                            $stack[] = $file;
                        }
                        elseif (is_file($file))
                        {
                            // and check the modification times of the files
                            $mtime = filemtime($file);
                            if ($mtime && $start < $mtime)
                            {
                                $pinfo = pathinfo($file);
                                // return true at the first positive match
                                if ($this->cssOnTheFly && $pinfo['extension'] == 'css') {
                                    // if the file is a css then then we send the whole path back
                                    return $mtime * 1000;
                                }
                                else {
                                    // otherwise return true
                                    return true;
                                }
                            }
                        }
                    }
                } // end foreach
            }
        } // end while

        return false;
    }

} // end LivephpMonitor

new LivephpMonitor();