This script can be used with Bitbucket's POST service to update packages on packagist.org.

bitbucket-proxy.php

<?php
/*
 * Dieses Script dient als "Proxy" zwischen Bitbucket und Packagist. Es empfängt
 * einen POST-Request über den generischen POST-Service von Bitbucket und leitet
 * diesen als PUT-Request an Packagist weiter, um das dazugehörige Paket zu
 * aktualisieren.
 */

function clean($var) {
  return get_magic_quotes_gpc() ? stripslashes($var) : $var;
}

$apiTokens = array(
	'xrstf' => '....'
);

error_reporting(0);
ini_set('display_errors', 'off');

////////////////////////////////////////////////////////////////////////////////
// check request

if (empty($_POST['payload']) || !is_string($_POST['payload'])) {
	header('HTTP/1.0 400 Bad Request');
	die('bad request');
}

if (empty($_GET['username']) || !is_string($_GET['username']) || !isset($apiTokens[$_GET['username']])) {
	header('HTTP/1.0 400 Bad Request');
	die('bad request');
}

////////////////////////////////////////////////////////////////////////////////
// determine repository from Bitbucket payload

$username = clean($_GET['username']);
$payload  = json_decode(clean($_POST['payload']));
$repo     = trim($payload->repository->absolute_url, '/');

////////////////////////////////////////////////////////////////////////////////
// deduct package name from repository's composer.json

require 'develop/guzzle.phar';

$client   = new Guzzle\Http\Client('https://bitbucket.org/');
$response = $client
	// cannot get the cert chain to work, and using HTTP yields a redirect to HTTPS anyway
	->setSslVerification(false, false, 0)
	->get($repo.'/raw/tip/composer.json')
	->send()
;

if ($response->getStatusCode() !== 200) {
	header('HTTP/1.0 404 Not Found');
	die('could not find composer.json');
}

$composer = json_decode($response->getBody(true));
$package  = $composer->name;

////////////////////////////////////////////////////////////////////////////////
// update package on packagist

$client = new Guzzle\Http\Client('https://packagist.org/');
$data   = http_build_query(array(
	'username'    => $username,
	'apiToken'    => $apiTokens[$username],
	'autoUpdated' => 1,
	'update'      => 1
), '', '&');

$client
	->setSslVerification('develop/packagist.pem', true, 2)
	->put('packages/'.$package.'?'.$data)
	->send()
;

print "done.";