Using SugarCRM's New RESTful API With Guzzle

gistfile1.php

<?php
use Guzzle\Common\Event;
use Guzzle\Http\Client;

// specify the REST web service to interact with
$url = 'http://sugarinstance/rest/v10';

// And admin username/password
$username = 'username';
$password = 'password';

$client = new Client($url);

//Authenticate and retrieve an OAuth2 Token
$request = $client->post('oauth2/token', null, array(
  'grant_type' => 'password',
  'client_id' => 'sugar',
  'username' => $username,
  'password' => $password,
));

$results = $request->send()->json();

$token = $results['access_token'];

//Register an Event Listener to automatically include 
//the OAuth2 token on all requests to the REST web service
$client->getEventDispatcher()->addListener(
  'request.before_send', function(Event $event) {
    $event['request']->setHeader('OAuth-Token', $token);
  }
);

//Retrieve all documents related to the specified account
$request = $client->get('/Accounts/' . $account_id . '/link/documents');
$result = $request->send()->json();

var_dump($result);