Auto git pull on every push to github

github callback handler.php

<?php

// TODO Handle tagged releases
// TODO Check current branch is checked out before pulling
// TODO Store sites in separate config file
// TODO Allow config file to be in folder above root.
// TODO Allow updating via $_GET?
// TODO Make sure sane git status before pulling?

// You can't view this file directly
if ( ! isset( $_POST['payload'] ) ) {

	header( 'Status: 301' );
	header( 'Location: http://hmn.md/' );
	exit;

}

global $github;

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

/**
 * Array of sites and their github details
 *
 * Format is array( [github repo name] => array( [site directory], [pull from branch_name or tag] );
 *
 */
$sites = array();

$sites['Human-Made-website']	= array(
	'dir'	=>	'humanmade',
	'ref'	=>	'master'
);

define( 'ABSPATH', dirname( dirname( __FILE__ ) ) );

// Check the payload is for one of the configured sites
if ( isset( $sites[$github->repository->name] ) && $site = $sites[$github->repository->name] ) {
	
	// If the directory doesn't exist then bail
	if ( ! file_exists( ABSPATH . '/' . $site['dir'] ) )
		return;

	$response = '';

	// If we're set to pull from a branch and that branch was part of the payload
	if ( $site['ref'] != 'tag' && $github->ref == 'refs/heads/' . $site['ref'] )

		// Then Git Pull
		$response = git_pull( $site['dir'] );

	// Send a notification
	if ( $response )
		notify( $response, $site );
}


/**
 * Perform a git pull & git submodule update command.
 * 
 * @access public
 * @param string $dir
 * @return void
 */
function git_pull( $dir ) {
	return shell_exec( 'cd ' . escshellarg( ABSPATH . '/' . $dir ) . ' ; git pull ; git submodule update --init --recursive' );
}


/**
 * Send an email notification with details of the payload that was just auto pulled
 * 
 * @access public
 * @param string $response
 * @param array $site
 * @return void
 */
function notify( $response, $site ) {

	global $github;

	mail(
		
		'example@email.com',
		
		'Git Callback from ' . $site['dir'],
		
		'
	
		<p><a href="mailto:' . reset( $github->commits )->author->email . '">' . reset( $github->commits )->author->name . '</a> pushed to <a href="http://' . $site['dir'] . '">' . $site['dir'] . '</a></p>
		
		<p>Commit: <a href="' . reset( $github->commits )->url . '">' . reset( $github->commits )->id . '</a></p>
		
		<p>Description:</p>
		
		<p><em>' . reset( $github->commits )->message . '</em></p>
		
		<p>Response:</p>
		
		<p><em>' . $response . '</em></p>
		
		<p>Full Details:</p>
		
		<p><pre>' . print_r( $github, true ) . '</pre></p>
	
		',
		
		'Content-type: text/html; charset=iso-8859-1'
	
	);

}