// LinkedIn API configuration

define(‘CLIENT_ID’, ‘LinkedIn_App_ID’);

define(‘CLIENT_SECRET’, ‘LinkedIn_App_Secret’); define(‘REDIRECT_URL’, ‘OAuth_Callback_URL’);

define(‘SCOPE’, ‘r_liteprofile r_emailaddress’); //API permissions

// Start session

if(!session_id()){ session_start(); }

// Include the oauth client library

require_once ‘oauth-client/http.php’;

require_once ‘oauth-client/oauth_client.php’;

$authUrl = $output = ”;

// If user already verified
if(isset($_SESSION[‘oauth_status’]) && $_SESSION[‘oauth_status’] == ‘verified’ && !empty($_SESSION[‘userData’])){
// Retrieve user’s profile data from session
$userData = $_SESSION[‘userData’];

// Prepare output to show LinkedIn profile data
if(!empty($userData)){
$output = ‘<h2>LinkedIn Profile Details</h2>’;
$output .= ‘<div class=”ac-data”>’;
$output .= ‘<img src=”‘.$userData[‘picture’].'”/>’;
$output .= ‘<p><b>LinkedIn ID:</b> ‘.$userData[‘oauth_uid’].'</p>’;
$output .= ‘<p><b>Name:</b> ‘.$userData[‘first_name’].’ ‘.$userData[‘last_name’].'</p>’;
$output .= ‘<p><b>Email:</b> ‘.$userData[’email’].'</p>’;
$output .= ‘<p><b>Logged in with:</b> LinkedIn’.'</p>’;
$output .= ‘<p><b>Profile Link:</b> <a href=”‘.$userData[‘link’].'” target=”_blank”>Click to visit LinkedIn page</a></p>’;
$output .= ‘<p><b>Logout from</b> <a href=”logout.php”>LinkedIn</a></p>’;
$output .= ‘</div>’;
}
}elseif((isset($_GET[“oauth_init”]) && $_GET[“oauth_init”] == 1) || (isset($_GET[‘oauth_token’]) && isset($_GET[‘oauth_verifier’])) || (isset($_GET[‘code’]) && isset($_GET[‘state’]))){
$client = new oauth_client_class;

$client->client_id = CLIENT_ID;
$client->client_secret = CLIENT_SECRET;
$client->redirect_uri = REDIRECT_URL;
$client->scope = SCOPE;
$client->debug = 1;
$client->debug_http = 1;
$application_line = __LINE__;

if(strlen($client->client_id) == 0 || strlen($client->client_secret) == 0){
die(‘Please go to LinkedIn Apps page https://www.linkedin.com/secure/developer?newapp= , ‘.
‘create an application, and in the line ‘.$application_line.
‘ set the client_id to Consumer key and client_secret with Consumer secret. ‘.
‘The Callback URL must be ‘.$client->redirect_uri.’. Make sure you enable the ‘.
‘necessary permissions to execute the API calls your application needs.’);
}

// If authentication returns success
if($success = $client->Initialize()){
if(($success = $client->Process())){
if(strlen($client->authorization_error)){
$client->error = $client->authorization_error;
$success = false;
}elseif(strlen($client->access_token)){
$success = $client->CallAPI(
‘https://api.linkedin.com/v2/me?projection=(id,firstName,lastName,profilePicture(displayImage~:playableStreams))’,
‘GET’, array(
‘format’=>’json’
), array(‘FailOnAccessError’=>true), $userInfo);
$emailRes = $client->CallAPI(
‘https://api.linkedin.com/v2/emailAddress?q=members&projection=(elements*(handle~))’,
‘GET’, array(
‘format’=>’json’
), array(‘FailOnAccessError’=>true), $userEmail);
}
}
$success = $client->Finalize($success);
}

if($client->exit) exit;

if(strlen($client->authorization_error)){
$client->error = $client->authorization_error;
$success = false;
}

if($success){
// Initialize User class

// Getting user’s profile data
$inUserData = array();
$inUserData[‘oauth_uid’] = !empty($userInfo->id)?$userInfo->id:”;
$inUserData[‘first_name’] = !empty($userInfo->firstName->localized->en_US)?$userInfo->firstName->localized->en_US:”;
$inUserData[‘last_name’] = !empty($userInfo->lastName->localized->en_US)?$userInfo->lastName->localized->en_US:”;
$inUserData[’email’] = !empty($userEmail->elements[0]->{‘handle~’}->emailAddress)?$userEmail->elements[0]->{‘handle~’}->emailAddress:”;
$inUserData[‘picture’] = !empty($userInfo->profilePicture->{‘displayImage~’}->elements[0]->identifiers[0]->identifier)?$userInfo->profilePicture->{‘displayImage~’}->elements[0]->identifiers[0]->identifier:”;
$inUserData[‘link’] = ‘https://www.linkedin.com/’;

// Insert or update user data to the database
$inUserData[‘oauth_provider’] = ‘linkedin’;
//Storing user data into session
$_SESSION[‘userData’] = $userData;
$_SESSION[‘oauth_status’] = ‘verified’;

//Redirect the user back to the same page
header(‘Location: ./’);
}else{
$output = ‘<h3 style=”color:red”>Error connecting to LinkedIn! try again later!</h3><p>’.HtmlSpecialChars($client->error).'</p>’;
}
}elseif(isset($_GET[“oauth_problem”]) && $_GET[“oauth_problem”] <> “”){
$output = ‘<h3 style=”color:red”>’.$_GET[“oauth_problem”].'</h3>’;
}else{
$authUrl = ‘?oauth_init=1’;

// Render LinkedIn login button
$output = ‘<a href=”?oauth_init=1″><img src=”images/linkedin-sign-in-btn.png”></a>’;
}
?>
<!DOCTYPE html>
<html lang=”en”>
<head>
<title>Login with LinkedIn using PHP by CodexWorld</title>

<!– Include stylesheet file –>
<link rel=”stylesheet” href=”css/style.css”/>
</head>
<body>
<div class=”container”>
<div class=”in-box”>
<!– Display login button / profile information –>
<?php echo $output; ?>
</div>
</div>
</body>
</html>