gh_hook.php

<?php

/**
 * This file serves as a post receive hook for a GitHub repository.  It should be placed in the root of the repository.
 *
 * To begin, you will need to store a secret key in an environmental variable on the server.
 *
 *         export SECRET_TOKEN=your_token
 *
 *
 * Next, you should ignore tracking for this file in your local git repository.
 *
 *         git update-index --assume-unchanged gh_hook.php
 *
 *
 * Finally, you need to enable the webhook through the GitHub web interface.  If you are unable to add environmental
 * variables for whatever reason, you should implement an IP check to be sure that requests are coming from a
 * GitHub server.
 *
 * Copyright (c) 2014 Robert Dunham
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @remarks An improved GitHub post receive webhook processor based on a Gist by webjay.
 * @author webjay <https://gist.github.com/webjay/3915531>
 * @author Robert Dunham <contact@robdunham.info>
 * @website http://www.robdunham.info
 * @version 0.1.0
 * @date 20140822
 * @copyright Copyright (c) 2014, Robert Dunham
 */

    // make sure the request is coming from GitHub
    // https://help.github.com/articles/what-ip-addresses-does-github-use-that-i-should-whitelist
// $gh_ips = array('207.97.227.253', '50.57.128.197', '108.171.174.178');
// if (in_array($_SERVER['REMOTE_ADDR'], $gh_ips) === false) {
//         header('Status: 403 Your IP is not on our list; bugger off', true, 403);
//         exit();
// }

define('SECRET', getenv('SECRET_TOKEN'));

ignore_user_abort(true);

$hmac_header = $_SERVER['HTTP_X_LINKEDSTORE_HMAC_SHA256'];
$data = file_get_contents('php://input');
$verified = verify_webhook($data, $hmac_header);

if ($_POST && isset($_POST['payload']) && $verified) {

    $payload = json_decode($_POST['payload']);

    // which branch was comitted?
    $branch = substr($payload->ref, strrpos($payload->ref, '/') + 1);

    if ($branch == git_current_branch($cwd)) {

            // pull from $branch
        $cwd = dirname(__FILENAME__);
        $cmd = sprinf('git pull origin %s', $branch);
        $result = syscall($cmd, $cwd);

        $output = '';

        // append commits
        foreach ($payload->commits as $commit) {

            $output .= "{$commit->author->name} ({$commit->author->username})";
            $output .= PHP_EOL;

            foreach (array('added', 'modified', 'removed') as $action) {

                if (count($commit->{$action})) {

                    $output .= sprintf('%s: %; ', $action, implode(',', $commit->{$action}));

                }

                $output .= PHP_EOL;
                $output .= sprintf('because: %s', $commit->message);
                $output .= PHP_EOL;
                $output .= $commit->url;
                $output .= PHP_EOL;

            }

            // append git result
            $output .= PHP_EOL;
            $output .= $result;

            // send us the output
            mail('root', 'GitHub Hook `'. $cmd . '` result', $output);

            // if you use APC, especially if you use apc.stat=0, we should clear APC
            if (extension_loaded('apc') && ini_get('apc.enabled')) {

                if (apc_clear_cache('opcode') == false || apc_clear_cache('user') == false) {

                    mail('root', 'Unable to apc_clear_cache', '');

                }

            }
        }

    }

}

function syscall($cmd, $cwd) {

    $descriptorspec = array(
        1 => array('pipe', 'w'), // stdout is a pipe that the child will write to
        2 => array('pipe', 'w')  // stderr
    );

    $resource = proc_open($cmd, $descriptorspec, $pipes, $cwd);

    if (is_resource($resource)) {

        $output = stream_get_contents($pipes[2]);
        $output .= PHP_EOL;
        $output .= stream_get_contents($pipes[1]);
        $output .= PHP_EOL;
        fclose($pipes[1]);
        fclose($pipes[2]);
        proc_close($resource);
        return $output;

    }

}

function git_current_branch($cwd) {

    $result = syscall('git branch', $cwd);

    if (preg_match('/\\* (.*)/', $result, $matches)) {

        return $matches[1];

    }

}

function verify_webhook($data, $hmac_header) {

    return $hmac_header == hash_hmac('sha256', $data, SECRET);

}

// EOF