Example of a call to rest_helper to do OAuth2 Username-Password Flow, to obtain a token in an Autonomous Client.

rest_login.php

/*********************************************************** 

  function for fetching the rest login token
  
  example of use:
  
  $response = rest_login();
  $instance_url =  $response->instance_url;
  $access_token = $response->access_token;
  
  $response = rest_helper(
    "< request url goes here >",
    array(), 
    'GET', 
    'json',
    "OAuth $access_token"
  );
  
  $data =  json_decode($response,true);
  
  code rest_helper can be found here:
    https://gist.github.com/gregmercer/6465114
  
***********************************************************/ 

function rest_login() {

  $grant_type = 'password';
  $client_id = '<your client id goes here>';
  $client_secret = '<your client secret goes here>';
  $username = '<your username goes here>';
  $password = '<your password goes here>';
  $login_url = '<your oauth2 token url goes here>';
  
  $response = rest_helper(
    $login_url, array(
    	'grant_type' => $grant_type,
    	'client_id' => $client_id,
    	'client_secret' => $client_secret,
    	'username' => $username,
    	'password' => $password 
    ), 
    'POST'
  );
  
  return $response;
  
}