Basic Usage
ℹ️ NOTE In most cases, you should use a specific official or third-party provider client library, rather than this base library alone.
Authorization Code Grant
The following example uses the out-of-the-box GenericProvider provided by this library. If you’re looking for a specific provider client (e.g., Facebook, Google, GitHub, etc.), take a look at our list of provider client libraries. HINT: You’re probably looking for a specific provider client.
The authorization code grant type is the most common grant type used when authenticating users with a third-party service. This grant type utilizes a client (this library), a service provider (the server), and a resource owner (the account with credentials to a protected—or owned—resource) to request access to resources owned by the user. This is often referred to as 3-legged OAuth, since there are three parties involved.
$provider = new \League\OAuth2\Client\Provider\GenericProvider([
'clientId' => 'XXXXXX', // The client ID assigned to you by the provider
'clientSecret' => 'XXXXXX', // The client password assigned to you by the provider
'redirectUri' => 'https://my.example.com/your-redirect-url/',
'urlAuthorize' => 'https://service.example.com/authorize',
'urlAccessToken' => 'https://service.example.com/token',
'urlResourceOwnerDetails' => 'https://service.example.com/resource'
]);
// A session is required to store some session data for later usage
session_start();
// If we don't have an authorization code then get one
if (!isset($_GET['code'])) {
// Fetch the authorization URL from the provider; this returns the
// urlAuthorize option and generates and applies any necessary parameters
// (e.g. state).
$authorizationUrl = $provider->getAuthorizationUrl();
// Get the state generated for you and store it to the session.
$_SESSION['oauth2state'] = $provider->getState();
// Optional, only required when PKCE is enabled.
// Get the PKCE code generated for you and store it to the session.
$_SESSION['oauth2pkceCode'] = $provider->getPkceCode();
// Redirect the user to the authorization URL.
header('Location: ' . $authorizationUrl);
exit;
// Check given state against previously stored one to mitigate CSRF attack
} elseif (empty($_GET['state']) || empty($_SESSION['oauth2state']) || $_GET['state'] !== $_SESSION['oauth2state']) {
if (isset($_SESSION['oauth2state'])) {
unset($_SESSION['oauth2state']);
}
exit('Invalid state');
} else {
try {
// Optional, only required when PKCE is enabled.
// Restore the PKCE code stored in the session.
$provider->setPkceCode($_SESSION['oauth2pkceCode']);
// Try to get an access token using the authorization code grant.
$tokens = $provider->getAccessToken('authorization_code', [
'code' => $_GET['code']
]);
// We have an access token, which we may use in authenticated
// requests against the service provider's API.
echo 'Access Token: ' . $tokens->getToken() . "<br>";
echo 'Refresh Token: ' . $tokens->getRefreshToken() . "<br>";
echo 'Expired in: ' . $tokens->getExpires() . "<br>";
echo 'Already expired? ' . ($tokens->hasExpired() ? 'expired' : 'not expired') . "<br>";
// Using the access token, we may look up details about the
// resource owner.
$resourceOwner = $provider->getResourceOwner($accessToken);
var_export($resourceOwner->toArray());
// The provider provides a way to get an authenticated API request for
// the service, using the access token; it returns an object conforming
// to Psr\Http\Message\RequestInterface.
$request = $provider->getAuthenticatedRequest(
'GET',
'https://service.example.com/resource',
$accessToken
);
} catch (\League\OAuth2\Client\Provider\Exception\IdentityProviderException $e) {
// Failed to get the access token or user details.
exit($e->getMessage());
}
}
Authorization Code Grant with PKCE
To enable PKCE (Proof Key for Code Exchange) you can set the pkceMethod option for the provider.
Supported methods are:
S256Recommended method. The code challenge will be hashed with sha256.plainNOT recommended. The code challenge will be sent as plain text. Only use this if no other option is possible.
You can configure the PKCE method as follows:
$provider = new \League\OAuth2\Client\Provider\GenericProvider([
// ...
// other options
// ...
'pkceMethod' => \League\OAuth2\Client\Provider\GenericProvider::PKCE_METHOD_S256
]);
The PKCE code needs to be used between requests and therefore be saved and restored, usually via the session. In the example above this is done as follows:
// Store the PKCE code after the `getAuthorizationUrl()` call.
$_SESSION['oauth2pkceCode'] = $provider->getPkceCode();
// ...
// Restore the PKCE code before the `getAccessToken()` call.
$provider->setPkceCode($_SESSION['oauth2pkceCode']);
Refreshing a Token
Once authorizing your application, you may refresh an expired token using a refresh token rather than going through the entire process of obtaining a new token. To do so, use the refresh token from your data store to request a new access token.
$provider = new \League\OAuth2\Client\Provider\GenericProvider([
'clientId' => 'XXXXXX', // The client ID assigned to you by the provider
'clientSecret' => 'XXXXXX', // The client password assigned to you by the provider
'redirectUri' => 'https://my.example.com/your-redirect-url/',
'urlAuthorize' => 'https://service.example.com/authorize',
'urlAccessToken' => 'https://service.example.com/token',
'urlResourceOwnerDetails' => 'https://service.example.com/resource'
]);
$existingAccessToken = getAccessTokenFromYourDataStore();
$existingRefreshToken = getRefreshTokenFromYourDataStore();
if ($existingAccessToken->hasExpired()) {
$tokens = $provider->getAccessToken('refresh_token', [
'refresh_token' => $existingRefreshToken
]);
// Purge old tokens and store new ones to your data store.
saveNewAccessTokenToYourDataStore($tokens->getToken());
saveNewRefreshTokenToYourDataStore($tokens->getRefreshToken());
}
Resource Owner Password Credentials Grant
Some service providers allow you to skip the authorization code step to exchange a user’s credentials (username and password) for an access token. This is referred to as the resource owner password credentials grant type.
According to section 1.3.3 of the OAuth 2.0 standard (emphasis added):
The credentials should only be used when there is a high degree of trust between the resource owner and the client (e.g., the client is part of the device operating system or a highly privileged application), and when other authorization grant types are not available (such as an authorization code).
🛑 DANGER! We advise against using this grant type if the service provider supports the authorization code grant type (see above), as this reinforces the password anti-pattern, allowing users to think it’s okay to trust third-party applications with their usernames and passwords.
That said, there are use-cases where the resource owner password credentials grant is acceptable and useful.
$provider = new \League\OAuth2\Client\Provider\GenericProvider([
'clientId' => 'XXXXXX', // The client ID assigned to you by the provider
'clientSecret' => 'XXXXXX', // The client password assigned to you by the provider
'redirectUri' => 'https://my.example.com/your-redirect-url/',
'urlAuthorize' => 'https://service.example.com/authorize',
'urlAccessToken' => 'https://service.example.com/token',
'urlResourceOwnerDetails' => 'https://service.example.com/resource'
]);
try {
// Try to get an access token using the resource owner password credentials grant.
$accessToken = $provider->getAccessToken('password', [
'username' => 'myuser',
'password' => 'mysupersecretpassword'
]);
} catch (\League\OAuth2\Client\Provider\Exception\IdentityProviderException $e) {
// Failed to get the access token
exit($e->getMessage());
}
Client Credentials Grant
When your application acts on its own behalf to access resources it controls or owns in a service provider, it may use the client credentials grant type.
The client credentials grant type is best when storing the credentials for your application privately and never exposing them (e.g., through the web browser, etc.) to end-users. This grant type functions like the resource owner password credentials grant type, but it does not request a user’s username or password. It uses only the client ID and client secret issued to your client by the service provider.
// Note: the GenericProvider requires the `urlAuthorize` option, even though
// it's not used in the OAuth 2.0 client credentials grant type.
$provider = new \League\OAuth2\Client\Provider\GenericProvider([
'clientId' => 'XXXXXX', // The client ID assigned to you by the provider
'clientSecret' => 'XXXXXX', // The client password assigned to you by the provider
'redirectUri' => 'https://my.example.com/your-redirect-url/',
'urlAuthorize' => 'https://service.example.com/authorize',
'urlAccessToken' => 'https://service.example.com/token',
'urlResourceOwnerDetails' => 'https://service.example.com/resource'
]);
try {
// Try to get an access token using the client credentials grant.
$accessToken = $provider->getAccessToken('client_credentials');
} catch (\League\OAuth2\Client\Provider\Exception\IdentityProviderException $e) {
// Failed to get the access token
exit($e->getMessage());
}
Using a Proxy
It is possible to use a proxy to debug HTTP calls made to a provider.
To use a proxy, set the proxy and verify options when creating your provider client instance. Make sure you enable SSL proxying in your proxy.
$provider = new \League\OAuth2\Client\Provider\GenericProvider([
'clientId' => 'XXXXXX', // The client ID assigned to you by the provider
'clientSecret' => 'XXXXXX', // The client password assigned to you by the provider
'redirectUri' => 'https://my.example.com/your-redirect-url/',
'urlAuthorize' => 'https://service.example.com/authorize',
'urlAccessToken' => 'https://service.example.com/token',
'urlResourceOwnerDetails' => 'https://service.example.com/resource',
'proxy' => '192.168.0.1:8888',
'verify' => false
]);