Facebook\Helper\JavaScriptHelper

If you're using the JavaScript SDK on your site, information on the logged in user is stored in a cookie. Use the FacebookJavaScriptHelper to obtain an access token or signed request from the cookie.

Usage

This helper will handle validating and decode the signed request from the cookie set by the JavaScript SDK.

$fb = new Facebook\Facebook([/* */]);
$jsHelper = $fb->getJavaScriptHelper();
$signedRequest = $jsHelper->getSignedRequest();

if ($signedRequest) {
  $payload = $signedRequest->getPayload();
  var_dump($payload);
}

If a user has already authenticated your app, you can also obtain an access token.

$fb = new Facebook\Facebook([/* */]);
$jsHelper = $fb->getJavaScriptHelper();

try {
  $accessToken = $jsHelper->getAccessToken();
} catch(Facebook\Exception\ResponseException $e) {
  // When Graph returns an error
  echo 'Graph returned an error: ' . $e->getMessage();
} catch(Facebook\Exception\SDKException $e) {
  // When validation fails or other local issues
  echo 'Facebook SDK returned an error: ' . $e->getMessage();
}

if (isset($accessToken)) {
  // Logged in.
}

You will likely want to make an Ajax request when the login state changes in the Facebook SDK for JavaScript. Information about that here: FB.event.subscribe

Instance Methods

__construct()

public FacebookJavaScriptHelper __construct(Application $app, FacebookClient $client, $graphVersion = null)

Upon instantiation, FacebookJavaScriptHelper validates and decodes the signed request that exists in the cookie set by the JavaScript SDK if present.

getAccessToken()

public Facebook\AccessToken|null getAccessToken( Facebook\Client $client )

Checks the signed request for authentication data and tries to obtain an access token access token.

getUserId()

public string|null getUserId()

A convenience method for obtaining a user's ID from the signed request if present. This will only return the user's ID if a valid signed request can be obtained and decoded and the user has already authorized the app.

$userId = $jsHelper->getUserId();

if ($userId) {
  // User is logged in
}

This is equivalent to accessing the user ID from the signed request entity.

$signedRequest = $jsHelper->getSignedRequest();

if ($signedRequest) {
  $userId = $signedRequest->getUserId();
  // OR
  $userId = $signedRequest->get('user_id');
}

getSignedRequest()

public Facebook\SignedRequest|null getSignedRequest()

Returns the signed request as a Facebook\SignedRequest entity if present.

getRawSignedRequest()

public string|null getRawSignedRequest()

Returns the raw encoded signed request as a string or null.