class.GitHubHook.php

<?php
error_reporting(0);

/**
 * GitHub Post-Receive Deployment Hook.
 *
 * @author Chin Lee <kwangchin@gmail.com>
 * @copyright Copyright (C) 2012 Chin Lee
 * @license http://www.opensource.org/licenses/mit-license.php The MIT License
 * @version 1.0
 */

class GitHubHook
{
  /**
   * @var string Remote IP of the person.
   * @since 1.0
   */
  private $_remoteIp = '';

  /**
   * @var object Payload from GitHub.
   * @since 1.0
   */
  private $_payload = '';

  /**
   * @var boolean Log debug messages.
   * @since 1.0
   */
  private $_debug = FALSE;

  /**
   * @var array Branches.
   * @since 1.0
   */
  private $_branches = array();

  /**
   * @var array GitHub's public IP addresses for hooks (CIDR notation).
   */
  private $_github_public_cidrs = array('192.30.252.0/22');

  /**
   * Constructor.
   * @since 1.0
   */
  function __construct() {
    /* Support for EC2 load balancers */
    if (
        isset($_SERVER['HTTP_X_FORWARDED_FOR']) &&
        filter_var($_SERVER['HTTP_X_FORWARDED_FOR'], FILTER_VALIDATE_IP)
      ) {
      $this->_remoteIp = $_SERVER['HTTP_X_FORWARDED_FOR'];
    } else {
      $this->_remoteIp = $_SERVER['REMOTE_ADDR'];
    }

    if (isset($_POST['payload'])) {
      $this->_payload  = json_decode($_POST['payload']);
    } else {
      $this->_notFound('Payload not available from: ' . $this->_remoteIp);
    }
  }

  /**
   * Centralize our 404.
   * @param string $reason Reason of 404 Not Found.
   * @since 1.1
   */
  private function _notFound($reason = NULL) {
    if ($reason !== NULL) {
      $this->log($reason);
    }

    header('HTTP/1.1 404 Not Found');
    echo '404 Not Found.';
    exit;
  }

  /**
   * IP in CIDRs Match - checks whether an IP exists within an array of CIDR ranges.
   * @link - http://stackoverflow.com/questions/10243594/find-whether-a-given-ip-exists-in-cidr-or-not?lq=1
   * @param string $ip - IP address in '127.0.0.1' format
   * @param array $cidrs - array storing CIDRS in 192.168.1.20/27 format.
   * @return bool
   */
  private function ip_in_cidrs($ip, $cidrs) {
	$ipu = explode('.', $ip);

	foreach ($ipu as &$v) {
		$v = str_pad(decbin($v), 8, '0', STR_PAD_LEFT);
	}

	$ipu = join('', $ipu);
	$result = FALSE;

	foreach ($cidrs as $cidr) {
		$parts = explode('/', $cidr);
		$ipc = explode('.', $parts[0]);

		foreach ($ipc as &$v) $v = str_pad(decbin($v), 8, '0', STR_PAD_LEFT); {
			$ipc = substr(join('', $ipc), 0, $parts[1]);
			$ipux = substr($ipu, 0, $parts[1]);
			$result = ($ipc === $ipux);
		}

		if ($result) break;
	}

	return $result;
  }

  /**
   * Enable log of debug messages.
   * @since 1.0
   */
  public function enableDebug() {
    $this->_debug = TRUE;
  }

  /**
   * Add a branch.
   * @param string $name Branch name, defaults to 'master'.
   * @param string $title Branch title, defaults to 'development'.
   * @param string $path Relative path to development directory, defaults to '/var/www/'.
   * @param array $author Contains authorized users' email addresses, defaults to everyone.
   * @param string $custom_cmd Custom command to run
   * @since 1.0
   */
  public function addBranch($name = 'master', $title = 'development', $path = '/var/www/', $author = array(), $custom_cmd = null) {
    $this->_branches[] = array(
      'name'   => $name,
      'title'  => $title,
      'path'   => $path,
      'author' => $author,
      'cmd'    => $custom_cmd
    );
  }

  /**
   * Handle error (defaults to trigger E_USER_ERROR);
   * @param string $message Message to log.
   * @since 1.0
   */
  public function error($code,$message) {
    if ($this->_debug) {
      trigger_error($message,E_USER_ERROR);
     }
  }

  /**
   * Log a message.
   * @param string $message Message to log.
   * @since 1.0
   */
  public function log($message) {
    if ($this->_debug) {
       error_log($message);
     }
  }

  /**
   * Deploys.
   * @since 1.0
   */
  public function deploy() {
      // Check the remote is a whitelisted GitHub public ip.
      if ($this->ip_in_cidrs($this->_remoteIp, $this->_github_public_cidrs)) {
          foreach ($this->_branches as $branch) {
              if ($this->_payload->ref == 'refs/heads/' . $branch['name']) {
                  $this->log('Deploying to ' . $branch['title'] . ' server');
                  $output=array(); 
                  $exit=0;
                  if (is_null($branch['cmd'])) {
                      $cmd='git --git-dir='. escapeshellarg($branch['path'] . '/.git') .' --work-tree='. escapeshellarg($branch['path']) .' pull origin '. escapeshellarg($branch['name']);
                  } else {
                      $cmd=escapeshellcmd($branch['cmd']);
                  }
                  exec($cmd,$output,$exit);
                  $msg="\t" . join(PHP_EOL . "\t", $output);
                  if (0!=$exit)
                      $this->error("error($exit): " . $branch['path'] . '$ ' . $cmd . PHP_EOL . $msg);
                  else
                      $this->log($msg); 
              }
          }
      } else {
          // IP of remote is invalid.
          $this->_notFound('IP address not recognized: ' . $this->_remoteIp);
      }
  }
}