API LinkedIn - Error on getaccesstoken() - php

Question

I m trying to get access to the linkedin api but like a lot of people, fail everytime and have this following message of error :
missing required parameters, includes an invalid parameter value, parameter more then once. : Unable to retrieve access token : appId or redirect uri does not match authorization code or authorization code expired
I've cheked the hosting server's timestamp and i revoke and create the token on the app admin before i launch the code (the faster i can due to the short life time of the authorization code given).
Here's my index file and just after the functions i use :
<?php
// VARS
define('API_KEY', 'xxxxxxxxxx');
define('API_SECRET', 'xxxxxxxxxx');
define('REDIRECT_URI', 'https://' . $_SERVER['SERVER_NAME'] . $_SERVER['SCRIPT_NAME']);
define('SCOPE', 'r_basicprofile');
session_name('linkedin');
session_start();
include('lib/functions.php');
// OAuth 2 Control Flow
if (isset($_GET['error'])) {
// LinkedIn returned an error
print $_GET['error'] . ': ' . $_GET['error_description'];
exit;
}
elseif (isset($_GET['code'])) {
// User authorized your application
getAccessToken();
}
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
getAuthorizationCode();
}
}
// Congratulations! You have a valid token. Now fetch your profile
$user = fetch('GET', '/v1/people/~:(firstName,lastName)');
print "Hello $user->firstName $user->lastName.";
?>
And the functions :
<?php
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");
exit;
}
function getAccessToken() {
$params = array('grant_type' => 'authorization_code',
'client_id' => API_KEY,
'client_secret' => API_SECRET,
'code' => $_GET['code'],
'redirect_uri' => REDIRECT_URI
);
var_dump($params);
// Access Token request
//$url = 'https://www.linkedin.com/uas/oauth2/accessToken?' . http_build_query($params);
$url = 'https://www.linkedin.com/uas/oauth2/accessToken';
$c = curl_init();
curl_setopt($c, CURLOPT_URL, $url);
curl_setopt($c, CURLOPT_RETURNTRANSFER, true);
curl_setopt($c, CURLOPT_HEADER, false);
curl_setopt($c, CURLOPT_POST,true);
curl_setopt($c, CURLOPT_POSTFIELDS, http_build_query($params));
$response = curl_exec($c); // on execute la requete
curl_close($c);
// 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() + $_SESSION['expires_in']; // absolute time
// DEBUG //
echo 'Retour get access token : </br>';
var_dump($token);
echo '</br>--------------------------</br></br>';
// ! DEBUG //
return true;
}
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
$url = 'https://api.linkedin.com' . $resource;
$c = curl_init();
curl_setopt($c, CURLOPT_URL, $url);
curl_setopt($c, CURLOPT_RETURNTRANSFER, true);
curl_setopt($c, CURLOPT_HEADER, false);
curl_setopt($c, CURLOPT_POSTFIELDS,http_build_query($params));
$response = curl_exec($c);
curl_close($c);
// DEBUG //
echo 'Retour fetch : </br>';
var_dump($response);
echo '</br>--------------------------</br></br>';
// ! DEBUG //
// Native PHP object, please
return json_decode($response);
}
?>
I tried many things but it never works. If someone see the issue tnaks a lot in advance.
Thanks

Answer 1

I have faced the same problem and my issue was caused by http_build_query() function, http://www.php.net/manual/en/function.http-build-query.php
for some reason it tries to encode the parameters to build a query string that will be used by the Linkedin services, if you try to construct the string manually it will pass and it will work.
and actually I reached this page while searching to figure out if its a PHP version issue or maybe the function http_build_query() take in account some environment variables like encoding and locale settings.
not sure but this fixed my issue.