BitBucket post-push hook

gistfile1.php

<?php
/**
 *
 * Receive POST requests from bitbucket.org and pull latest based on incoming branch filtering.
 * Note: You'll need to setup www-data user (Debian) with SSH keys in the /var/www/.ssh dir and add the public key to bitbucket's UI.
 */
class bitbucketGit {

    /**
     *
     * @var string
     */
    protected static $document_root = '/var/www/my-site';


    /**
     * Example array output from bog-standard BitBucket post-push POST request:
     * array (
     *      'payload' => '{"repository": {"website": "http://my-site/", "fork": false, "name": "my-site", "scm": "git", "owner": "phptek", "absolute_url": "/phptek/my-site.com/", "slug": "my-site.com", "is_private": true}, "truncated": false, "commits": [{"node": "70fee6925a4e", "files": [{"type": "added", "file": "htdocs/bitbucket-post-push.php"}], "raw_author": "Russell Michell <russ@xyz.com>", "utctimestamp": "2014-05-17 09:07:01+00:00", "author": "phptek", "timestamp": "2014-05-17 11:07:01", "raw_node": "70fee6925a4e9bf1567acf4b256174aea5c1ed7a", "parents": ["1b9c2f650309"], "branch": "master-bitbucket-test", "message": "Added another test\\n", "revision": null, "size": -1}], "canon_url": "https://bitbucket.org", "user": "phptek"}',
     * )
     *
     */
    public function bitbucket() {
        if(!$this->checkInput()) {
            $this->log("Incoming payload was empty.");
            exit(1);
        }

        $incoming = json_decode($_POST['payload'], true);

        // Discard data for any other branch than the following
        $branchMap = array(
            'live' => 'live/htdocs',
            'staging' => 'stage/htdocs'
        );

        $incoming_branch = $incoming['commits'][0]['branch'];
        if(!in_array($incoming_branch, array_keys($branchMap))) {
            $this->log("Incoming branch wasn't one of the desired branches: " .  $incoming_branch);
            exit(1);
        }

        $path = self::$document_root . '/' . $branchMap[$incoming_branch];

        // Data is cosha. Next steps, change to correct dir
        if(!chdir($path)) {
            $this->log("Couldn't change dir to: " . $path);
            exit(1);
        }

        // We're in, now pull latest codebase onto the server from BitBucket
        $cmd = 'git pull bitbucket ' . $incoming['branch'];

        if(!system($cmd)) {
            $this->log("Couldn't execute command: " . $cmd);
            exit(1);
        }
    }

    /**
     * Check incoming data
     *
     * @return boolean
     */
    protected function checkInput() {
        $isPostEmpty = (!count($_POST));
        $isNoPayload = (isset($_POST['payload']) && !strlen($_POST['payload']));
        if($isPostEmpty || $isNoPayload) {
            return false;
        }
        return true;
    }

    /**
     *
     * @param string $msg
     * @return void
     */
    protected function log($msg) {
        file_put_contents('./bb.out', $msg . PHP_EOL, FILE_APPEND);
    }

}

$bb = new bitbucketGit();
$bb->bitbucket();
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