This project provides an OAuth 2.0 "Authorization Code Grant" client as described in RFC 6749, section 4.1.
The client can be controlled through a PHP API that is used from the application trying to access an OAuth 2.0 protected resource server.
The following features are supported:
- "Authorization Code Grant" Profile
- Refresh Tokens
Licensed under the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
https://www.gnu.org/licenses/lgpl.html
This roughly means that if you write some PHP application that uses this client you do not need to release your application under (L)GPL as well. Refer to the license for the exact details.
If you want to integrate this OAuth client in your application you need to answer some questions:
- Where am I going to store the access tokens?
- How do I make an endpoint URL available in my application that can be used as a redirect URL for the callback from the authorization server?
Next to this you need OAuth client credentials from the authorization server
and REST API documentation from the service you want to connect to. You for
instance need to know the authorize_endpoint, the token_endpoint, the
client_id and client_secret.
As for storing access tokens, this library includes two backends. One for storing the tokens in a database (using the PHP PDO abstraction layer) and one for storing them in the user session. The first one requires some setup, the second one is very easy to use (no configuration) but will not allow the client to access data at the resource server without the session data being available. A more robust implementation would use the PDO backed storage. For testing purposes or very simple setups the session implementation makes the most sense.
For accessing the resource service a Guzzle plugin is available that will help you with that.
The sections below will walk through all the steps you need in order to get the client working.
In addition to this, a full example is available in the example directory.
This includes index.php that does the token request and requests the data.
Also a callback.php is included to show how to use the Callback API. Next
to this a composer.json is included for use with Composer.
In order to easily integrate with your application it is recommended to use Composer to install the dependencies. You need to install two libraries to use this library:
fkooman/php-oauth-clientfkooman/guzzle-bearer-auth-plugin
Below is a simple example composer.json file you could use:
{
"name": "fkooman/my-demo-oauth-app",
"require": {
"fkooman/guzzle-bearer-auth-plugin": "dev-master",
"fkooman/php-oauth-client": "dev-master"
}
}
You can create an client configuration object as shown below. You can fetch
this from a configuration file in your application if desired. Below is an
example of the generic ClientConfig class:
$clientConfig = new ClientConfig(
array(
"authorize_endpoint" => "http://localhost/oauth/php-oauth/authorize.php",
"client_id" => "foo",
"client_secret" => "foobar",
"token_endpoint" => "http://localhost/oauth/php-oauth/token.php",
)
);
There is also a GoogleClientConfig class that you can use with Google's
client_secrets.json file format:
// Google
$googleClientConfig = new GoogleClientConfig(
json_decode(file_get_contents("client_secrets.json"), true)
);
Now you can initialize the Api object:
$api = new Api("foo", $clientConfig, new SessionStorage(), new \Guzzle\Http\Client());
In this example we use the SessionStorage token storage backend. This is used
to keep the obtained tokens in the user session. For testing purposes this is
sufficient, for production deployments you will want to use the PdoStorage
backend instead, see below.
You also need to provide an instance of Guzzle which is a HTTP client used to exchange authorization codes for access tokens, or use a refresh token to obtain a new access token.
In order to request tokens you need to use two methods: Api::getAccessToken()
and Api::getAuthorizeUri(). The first one is used to see if there is already
a token available, the second to obtain an URL to which you have to redirect
the browser from your application. The example below will show you how to use
these methods.
Before you can call these methods you need to create a Context object to
specify for which user you are requesting this access token and what the scope
is you want to request at the authorization server.
$context = new Context("john.doe@example.org", new Scope("read"));
This means that you will request a token bound to john.doe@example.org with
the scope read. The user you specify here is typically the user identifier
you use in your application that wants to integrate with the OAuth 2.0
protected resource. At your service the user can for example be
john.doe@example.org. This identifier is in no way related to the identity
of the user at the remote service, it is just used for book keeping the
access tokens. If you do not want to request any particular scope you can use
new Scope().
Now you can see if an access token is already available:
$accessToken = $api->getAccessToken($context);
This call returns false if no access token is available for this user and
scope and none could be obtained through the backchannel using a refresh token.
This means that there never was a token or it expired. The token can still be
revoked, but we cannot see that right now, we'll find that out when we try to
use it later.
Assuming the getAccessToken($context) call returns false, i.e.: there was
no token, we have to obtain authorization:
if (false === $accessToken) {
/* no valid access token available, go to authorization server */
header("HTTP/1.1 302 Found");
header("Location: " . $api->getAuthorizeUri($context));
exit;
}
This is the simplest way if your application is not using any framework. If your application uses a framework you can probably use that to do "proper" redirect without setting the HTTP headers yourself. You should use this!
After this, the flow of this script ends and the user is redirected to the authorization server. Once there, the user accepts the client request and is redirected back to the redirection URL you registered at the OAuth 2.0 service provider. You also need to put some code at this callback location, see the next section below.
Assuming you already had an access token, i.e.: the response from
Api::getAccessToken() was not false you can now try to get the resource.
This example uses Guzzle as well:
$apiUrl = 'http://www.example.org/resource';
try {
$client = new Client();
$bearerAuth = new BearerAuth($accessToken->getAccessToken());
$client->addSubscriber($bearerAuth);
$response = $client->get($apiUrl)->send();
header("Content-Type: application/json");
echo $response->getBody();
} catch (BearerErrorResponseException $e) {
if ("invalid_token" === $e->getBearerReason()) {
// the token we used was invalid, possibly revoked, we throw it away
$api->deleteAccessToken($context);
$api->deleteRefreshToken($context);
/* no valid access token available, go to authorization server */
header("HTTP/1.1 302 Found");
header("Location: " . $api->getAuthorizeUri($context));
exit;
}
throw $e;
}
Pay special attention to the BearerErrorResponseException where both the
access token and refresh token are deleted when the access token does not work.
If that happens, the browser is redirected like in the case when there was no
token yet.
The above situation assumed you already had a valid access token. If you didn't you got redirected to the authorization server where you had to accept the request for access to your data. Assuming that all went well you will be redirected back the the redirection URI you registered at the OAuth 2.0 service.
The of the Callback class is very similar to the Api class. We assume you
also create the ClientConfig object here, like in the Api case. The
contents of this file are assumed to be in callback.php.
try {
$cb = new Callback("foo", $clientConfig, new SessionStorage(), new \Guzzle\Http\Client());
$cb->handleCallback($_GET);
header("HTTP/1.1 302 Found");
header("Location: http://www.example.org/index.php");
} catch (AuthorizeException $e) {
// this exception is thrown by Callback when the OAuth server returns a
// specific error message for the client, e.g.: the user did not authorize
// the request
echo sprintf("ERROR: %s, DESCRIPTION: %s", $e->getMessage(), $e->getDescription());
} catch (\Exception $e) {
// other error, these should never occur in the normal flow
echo sprintf("ERROR: %s", $e->getMessage());
}
This is all that is needed here. The authorization code will be extracted from
the callback URL and used to obtain an access token. The access token will be
stored in the token storage, here SessionStorage and the browser will be
redirected back to the page where the Api calls are made, here index.php.
You can store the tokens either in SessionStorage or PdoStorage. The first
one is already demonstrated above and requires no further configuration, it
just works out of the box.
$tokenStorage = new SessionStorage();
The PDO backend requires you specifying the database you want to use:
$db = new PDO("sqlite:/path/to/db/client.sqlite");
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$tokenStorage = new PdoStorage($db);
In both cases you can use $tokenStorage in the constructor where before we
put new SessionStorage() there directly. See the PHP PDO documentation on how
to specify other databases.
Please note that if you use SQLite, please note that the directory you write the file to needs to be writable to the web server as well!
In order to log all the requests the OAuth library makes to the token endpoint it is possible to use e.g. the Monolog adapter for this. Below is an example on how to do this. For production systems you may want to integrate with your own logging framework, set the appropriate log level, e.g. only log on errors.
So instead of just using
new Client()
You can use the following snippet:
use Monolog\Logger;
use Monolog\Handler\StreamHandler;
use Guzzle\Plugin\Log\LogPlugin;
use Guzzle\Log\MessageFormatter;
use Guzzle\Log\MonologLogAdapter;
/* create the log channel */
$log = new Logger('my-app');
$log->pushHandler(new StreamHandler(sprintf("%s/data/client.log", __DIR__), Logger::DEBUG));
$logPlugin = new LogPlugin(new MonologLogAdapter($log), MessageFormatter::DEBUG_FORMAT);
$httpClient = new Client();
$httpClient->addSubscriber($logPlugin);
Now you can feed the $httpClient to the Api and Callback classes and the
requests and responses including their bodies will be logged.