LinkedIn API Cheat Sheet

<?php
    // Change these back to your things
    define('API_KEY',      'YOUR API KEY');
    define('API_SECRET',   'YOUR API SECRET');
    define('REDIRECT_URI',  'http://localhost/');

    // I've changed the scope to work for what we generally have access to
    define('SCOPE', 'r_basicprofile r_emailaddress');

    // This stuff I believe it used if you have a database
    session_name('linkedin');
    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'] == $_GET['state']) {
            // Get token so you can make API calls
            getAccessToken();
        } else {
            // CSRF attack? Or did you mix up your states?
            exit;
        }
    } else {
        if ((empty($_SESSION['expires_at'])) || (time() > $_SESSION['expires_at'])) {
            // Token has expired, clear the state
            $_SESSION = array();
        }
        if (empty($_SESSION['access_token'])) {
            // Start authorization process
            getAuthorizationCode();
        }
    }

    // You have a valid token. Now fetch your profile.
    // I've just put in some dummy fields for now, but hopefully these should do it.
    $user = fetch('GET', '/v1/people/~:(first-name,last-name,email-address,phone-numbers,num-connections,picture-url,location,positions,summary,specialties,industry)');

    // I've just shoved the responses into some variables from the $user dict response

    // STORE THE RESULTS IN AN ARRAY

    $res = array();

    $res[] = $user->firstName;
    $res[] = $user->lastName;
    $res[] = $user->emailAddress;
    $res[] = $user->phoneNumbers;
    $res[] = $user->numConnections;
    $res[] = $user->pictureUrl;
    $res[] = $user->location->country->code;
    $res[] = $user->location->name;
    $res[] = $user->summary;
    $res[] = $user->specialties;
    $res[] = $user->industry;
    $res[] = $user->positions;

    echo  nl2br("First name: ". $res[0] . "\n");
    echo  nl2br("Last name: ". $res[1] . "\n");
    echo  nl2br("Email Address: " . $res[2] . "\n");
    echo  nl2br("Phone Numbers: ". $res[3] . "\n");
    echo  nl2br("Num Connections: ". $res[4] . "\n");
    echo  nl2br("Picture Url: " . $res[5] . "\n");
    echo  nl2br("Location Country Code: " . $res[6]. "\n");
    echo  nl2br("Location Name: ". $res[7] . "\n");
    echo  nl2br("Summary: " . $res[8] . "\n");
    echo  nl2br("Specialties: ". $res[9] . "\n");
    echo  nl2br("Industry: ". $res[10] . "\n");
    echo  nl2br("Positions: " . $res[11] . "\n");

    exit;

    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,
                  );

        // 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;
    }

    // this fetch should be the main thing that you really need to add to what you already have!

    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);
    }

?>
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