LinkedIn API Request Failed HTTP 400 - php

Question

I am having problems with the LinkedIn API, sometimes it's working fine and sometimes I just get the following error:
Message:
file_get_contents(https://www.linkedin.com/uas/oauth2/accessToken?grant_type=authorization_code&client_id=####&client_secret=####&code=AQTJH8Hm9K8gmriHaDPLbJm_-E8OnbsiUCZvz32Jv_wD6idTW7Se8v0dohVUH0m8zGWzfKkanCC_NT3smdkoykE0nF88nH-tntK35UqHH4LwgzfcNBc&redirect_uri=http%3A%2F%2Fpeerbriefmini.local%2Flinkedincontroller)
[function.file-get-contents]: failed to open stream: HTTP request
failed! HTTP/1.0 400 request#no_content_length
I have taken out my app id and secret. Is there are reason why it would sometimes work?
Edit : added the php code, which works in codeigniter
<?php
class Linkedincontroller extends CI_Controller {
public function __construct() {
parent::__construct();
$this->config->load('linkedin');
$this->load->library('linkedin');
$this->load->model('account_model');
}
public function index() {
// Change these
define('API_KEY', '###');
define('API_SECRET', '##');
define('REDIRECT_URI', base_url().'linkedincontroller');
define('SCOPE', 'r_fullprofile r_emailaddress rw_nus r_basicprofile r_contactinfo');
// You'll probably use a database
session_name('dfsfsdfsdf');
session_start();
// OAuth 2 Control Flow
if (isset($_GET['error'])) {
// LinkedIn returned an error
print $_GET['error'] . ': ' . $_GET['error_description'];
exit;
} elseif (isset($_GET['code'])) {
// User authorized your application
if ($_SESSION['state'] == $_GET['state']) {
// Get token so you can make API calls
$this->getAccessToken();
} else {
// CSRF attack? Or did you mix up your states?
//exit;
}
} else {
if ((empty($_SESSION['expires_at'])) || (time() > $_SESSION['expires_at'])) {
// Token has expired, clear the state
$_SESSION = array();
}
if (empty($_SESSION['access_token'])) {
// Start authorization process
$this->getAuthorizationCode();
}
}
// Congratulations! You have a valid token. Now fetch your profile
$user = $this->fetch('GET', '/v1/people/~:(id,first-name,last-name,main-address,picture-url,public-profile-url,email-address,interests,skills,languages,certifications,educations,positions,courses)');
$linkedin_id = $user['id'];
if(isset($linkedin_id)) {
//var_dump($user);
$linkedin_id = $user['id'];
$linkedin_url = $user['publicProfileUrl'];
$first_name = $user['firstName'];
$last_name = $user['lastName'];
$email = $user['emailAddress'];
$profile_picture = $user['pictureUrl'];
$address = $user['mainAddress'];
$this->account_model->insert_database('accounts',
array(
'account_confirmed' => 1,
'account_active' => 1,
'account_level' => 'Parent',
'account_role' => 'User',
'account_type' => 'Referrer',
'account_completed_level' => 1,
'master_account' => 1,
'account_holder' => $first_name . ' ' .$last_name,
'email' => $email,
'linkedin_id' => $linkedin_id
)
);
$account_id = $this->db->insert_id();
$this->account_model->insert_database('profiles',
array(
'account_id' => $account_id,
'profile_picture' => $profile_picture,
'linkedin_url' => $linkedin_url,
'address' => $address
)
);
// set flash data
$this->session->set_userdata(
array('linkedin_id' => $linkedin_id,
'first_name' => $first_name,
'last_name' => $last_name,
'email' => $email,
'profile_picture' => $profile_picture,
'residential_address' => $address)
);
// redirect back to reg page with profile data
redirect('register');
}else{
$data['header_text'] = $this->account_model->header_text();
$data['header_links'] = $this->account_model->header_links();
$data['user_picture'] = '';
$data['nickname'] = $this->account_model->user_nickname();
$this->load->view('template/header', $data);
$data['error_message'] = 'Unknown LinkedIn credentials.';
$this->load->view('error', $data);
$this->load->view('template/footer');
}
}
// empty fields
private function empty_fields($value) {
if(isset($value)) {
return $value;
}else{
return NULL;
}
}
// authorization code
private function getAuthorizationCode() {
$params = array('response_type' => 'code',
'client_id' => API_KEY,
'scope' => SCOPE,
'state' => uniqid('', true), // unique long string
'redirect_uri' => REDIRECT_URI,
);
// Authentication request
$url = 'https://www.linkedin.com/uas/oauth2/authorization?' . http_build_query($params);
// Needed to identify request when it returns to us
$_SESSION['state'] = $params['state'];
// Redirect user to authenticate
header("Location: $url");
}
// get access token
private function getAccessToken() {
$params = array('grant_type' => 'authorization_code',
'client_id' => API_KEY,
'client_secret' => API_SECRET,
'code' => $_GET['code'],
'redirect_uri' => REDIRECT_URI,
);
// Access Token request
$url = 'https://www.linkedin.com/uas/oauth2/accessToken?' . http_build_query($params);
// Tell streams to make a POST request
$context = stream_context_create(
array('http' =>
array('method' => 'POST',
)
)
);
// Retrieve access token information
$response = file_get_contents($url, false, $context);
// Native PHP object, please
$token = json_decode($response);
// Store access token and expiration time
$_SESSION['access_token'] = $token->access_token; // guard this!
$_SESSION['expires_in'] = $token->expires_in; // relative time (in seconds)
$_SESSION['expires_at'] = time() + $_SESSION['expires_in']; // absolute time
return true;
}
// fetch
private function fetch($method, $resource, $body = '') {
$params = array('oauth2_access_token' => $_SESSION['access_token'],
'format' => 'json',
);
// Need to use HTTPS
$url = 'https://api.linkedin.com' . $resource . '?' . http_build_query($params);
// Tell streams to make a (GET, POST, PUT, or DELETE) request
$context = stream_context_create(
array('http' =>
array('method' => $method,
)
)
);
// Hocus Pocus
$response = file_get_contents($url, false, $context);
// Native PHP object, please
return json_decode($response, true);
//return json_decode($response, false);
}
}
?>