oauth2-server-php

An OAuth2.0 Server in PHP! View the Full Working Demo (code)

Installation

This library follows the zend PSR-0 standards. A number of autoloaders exist which can autoload this library for that reason, but if you are not using one, you can register the OAuth2_Autoloader:

require_once('/path/to/oauth2-server-php/src/OAuth2/Autoloader.php');
OAuth2_Autoloader::register();

Using Composer? Add the following to composer.json:

{
    "require": {
        "bshaffer/oauth2-server-php": "dev-develop",
        ...
    },
    ...
}

And then run composer.phar install

It is highly recommended you check out the v0.7 tag to ensure your application doesn't break from backwards-compatibility issues, but also this means you will not receive the latest changes.

Learning OAuth2.0

If you are new to OAuth2, take a little time first to look at the Oauth2 Demo Application and the source code, and read up on OAuth2 Flows. For everything else, consult the OAuth2.0 Specification

Get Started

Here is an example of a bare-bones OAuth2 Server implementation:

$storage = new OAuth2_Storage_Pdo(array('dsn' => $dsn, 'username' => $username, 'password' => $password));
$server = new OAuth2_Server($storage);
$server->addGrantType(new OAuth2_GrantType_AuthorizationCode($storage)); // or any grant type you like!
$server->handleTokenRequest(OAuth2_Request::createFromGlobals(), new OAuth2_Response())->send();

This library requires you to define a Storage object, containing instrutions on how to interact with objects in your storage layer such as OAuth Clients and Authorization Codes. Built-in storage classes include PDO, Redis, and Mongo. The interfaces allow (and encourage) the use of your own Storage objects to fit your application's implementation.

Once you've created a storage object, pass it to the server object and define which Grant Types your server is to support. See the list of supported Grant Types below.

The final step, once the Server object is set up, is to handle the incoming request. Consult the Server Methods, or follow the Step-by-Step Walkthrough to familiarize yourself with the types of requests involved in OAuth2.0 workflows.

Step-by-Step Walkthrough

The following instructions provide a detailed walkthrough to help you get an OAuth2 server up and running. To see the codebase of an existing OAuth2 server implementing this library, check out the OAuth2 Demo.

Define your Schema

The quickest way to get started is to use the following schema to create the default database:

CREATE TABLE oauth_clients (client_id TEXT, client_secret TEXT, redirect_uri TEXT);
CREATE TABLE oauth_access_tokens (access_token TEXT, client_id TEXT, user_id TEXT, expires TIMESTAMP, scope TEXT);
CREATE TABLE oauth_authorization_codes (authorization_code TEXT, client_id TEXT, user_id TEXT, redirect_uri TEXT, expires TIMESTAMP, scope TEXT);
CREATE TABLE oauth_users (username TEXT, password TEXT, first_name TEXT, last_name TEXT);
CREATE TABLE oauth_refresh_tokens (refresh_token TEXT, client_id TEXT, user_id TEXT, expires TIMESTAMP, scope TEXT);

Create a Token Controller

The first thing you will do is create the Token Controller. This is the URI which returns an OAuth2.0 Token to the client. Here is an example of a token controller in the file token.php:

// error reporting (this is a demo, after all!)
ini_set('display_errors',1);error_reporting(E_ALL);

// Autoloading (composer is preferred, but for this example let's just do this)
require_once('path/to/oauth2-server-php/src/OAuth2/Autoloader.php');
OAuth2_Autoloader::register();

// $dsn is the Data Source Name for your database, for exmaple "mysql:dbname=my_oauth2_db;host=localhost"
$storage = new OAuth2_Storage_Pdo(array('dsn' => $dsn, 'username' => $username, 'password' => $password));

// Pass a storage object or array of storage objects to the OAuth2 server class
$server = new OAuth2_Server($storage);

// Add the "Client Credentials" grant type (it is the simplest of the grant types)
$server->addGrantType(new OAuth2_GrantType_ClientCredentials($storage));

// Handle a request for an OAuth2.0 Access Token and send the response to the client
$server->handleTokenRequest(OAuth2_Request::createFromGlobals(), new OAuth2_Response())->send();

Congratulatons! You have created a Token Controller! Do you want to see it in action? Run the following SQL to create an OAuth Client:

INSERT INTO oauth_clients (client_id, client_secret, redirect_uri) VALUES ("testclient", "testpass", "http://fake/");

Now run the following from the command line:

curl -u testclient:testpass http://localhost/token.php -d 'grant_type=client_credentials'

Note: http://localhost/token.php assumes you have the file token.php on your local machine, and you have set up the "localhost" webhost to point to it. This may vary for your application.

If everything works, you should receive a response like this:

{"access_token":"03807cb390319329bdf6c777d4dfae9c0d3b3c35","expires_in":3600,"token_type":"bearer","scope":null}

Create a Resource Controller

Now that you are creating tokens, you'll want to validate them in your APIs. Here is an example of a resource controller in the file resource.php:

// error reporting again
ini_set('display_errors',1);error_reporting(E_ALL);

// Autoloading again
require_once('path/to/oauth2-server-php/src/OAuth2/Autoloader.php');
OAuth2_Autoloader::register();

// create your storage again
$storage = new OAuth2_Storage_Pdo(array('dsn' => $dsn, 'username' => $username, 'password' => $password));

// create your server again
$server = new OAuth2_Server($storage);

// Handle a request for an OAuth2.0 Access Token and send the response to the client
if (!$server->verifyResourceRequest(OAuth2_Request::createFromGlobals(), new OAuth2_Response())) {
    $server->getResponse()->send();
    die;
}
echo json_encode(array('success' => true, 'message' => 'You accessed my APIs!'));

Now run the following from the command line:

curl http://localhost/resource.php -d 'access_token=YOUR_TOKEN'

Note: Use the value returned in "access_token" from the previous step in place of YOUR_TOKEN

If all goes well, you should receive a response like this:

{"success":true,"message":"You accessed my APIs!"}

Create an Authorize Controller

Authorize Controllers are the "killer feature" of OAuth2, and allow for your users to authorize third party applications. Here is an example of an authorize controller in authorize.php:

// error reporting again
ini_set('display_errors',1);error_reporting(E_ALL);

// Autoloading again
require_once('path/to/oauth2-server-php/src/OAuth2/Autoloader.php');
OAuth2_Autoloader::register();

// create your storage again
$storage = new OAuth2_Storage_Pdo(array('dsn' => $dsn, 'username' => $username, 'password' => $password));

// create your server again
$server = new OAuth2_Server($storage);

// Add the "Authorization Code" grant type (this is required for authorization flows)
$server->addGrantType(new OAuth2_GrantType_AuthorizationCode($storage));

$request = OAuth2_Request::createFromGlobals();
$response = new OAuth2_Response();

// validate the authorize request
if (!$server->validateAuthorizeRequest($request, $response)) {
    $response->send();
    die;
}
// display an authorization form
if (empty($_POST)) {
  exit('
<form method="post">
  <label>Do You Authorize TestClient?</label><br />
  <input type="submit" name="authorized" value="yes">
  <input type="submit" name="authorized" value="no">
</form>');
}
// print the authorization code if the user has authorized your client
$is_authorized = ($_POST['authorized'] === 'yes');
$server->handleAuthorizeRequest($request, $response, $is_authorized);
if ($is_authorized) {
  // this is only here so that you get to see your code in the cURL request. Otherwise, we'd redirect back to the client
  $code = substr($response->getHttpHeader('Location'), strpos($response->getHttpHeader('Location'), 'code=')+5);
  exit("SUCCESS! Authorization Code: $code");
}
$response->send();

Now paste the following URL in your browser

http://localhost/authorize.php?response_type=code&client_id=testclient

You will be prompted with an authorization form, and receive an authorization code upon clicking "yes"

Note: The Authorization Code can now be used to receive an access token from your previously created token.php endpoint. Just add the following grant type to token.php:

$server->addGrantType(new OAuth2_GrantType_AuthorizationCode($storage));

And call this endpoint using the returned authorization code:

curl -u testclient:testpass http://localhost/token.php -d 'grant_type=authorization_code&redirect_uri=http://fake/&code=YOUR_CODE'

Grant Types

There are many supported grant types in the OAuth2 specification, and this library allows for the addition of custom grant types as well. Supported grant types are as follows:

1. Authorization Code

   An authorization code obtained by user authorization is exchanged for a token

2. Implicit

   As part of user authorization, a token is retured to the client instead of an authorization code

3. Resource Owner Password Credentials

   The username and password are submitted as part of the request, and a token is issued upon successful authentication

4. Client Credentials

   The client can use their credentials to retrieve an access token directly, which will allow access to resources under the client's control

5. JWT Authorization Grant

   The client can submit a JWT (JSON Web Token) in a request to the token endpoint. An access token (without a refresh token) is then returned directly.

6. Refresh Token

   The client can submit refresh token and recieve a new access token e.g. it may be necessary to do this if the access_token had expired.

7. Extension Grant

   Create your own grant type by implementing the OAuth2_GrantTypeInterface and adding it to the OAuth2 Server object.

When submitting a request for an access_token using either the 'Authorization Code' or 'Resource Owner Password Credential' grant, a refresh_token is provided. However, When using the refresh_token from above to request a new access_token, a new refresh_token is not provided. The spec does not strictly require a refresh_token be granted but it is still possible to do it.

As a result, the option always_issue_new_refresh_token was added (defaults to FALSE) in the OAuth2_GrantType_RefreshToken class. So, by default a new refresh token is not issued, but you can easily configure this to do so by setting 'always_issue_new_refresh_token' => true

If you want to support more than one grant type it is possible to add more when the Server object is created:

$server->addGrantType(new OAuth2_GrantType_UserCredentials($storage));
$server->addGrantType(new OAuth2_GrantType_RefreshToken($storage));
$server->addGrantType(new OAuth2_GrantType_AuthorizationCode($storage));

Server Methods

...an end-user (resource owner) can grant a printing service (client) access to her protected photos stored at a photo sharing service (resource server), without sharing her username and password with the printing service. Instead, she authenticates directly with a server trusted by the photo sharing service (authorization server), which issues the printing service delegation- specific credentials (access token).

~ OAuth2 (draft #31)

Most OAuth2 APIs will have endpoints for Authorize Requests, Token Requests, and Resource Requests. The OAuth2_Server object has methods to handle each of these requests.

Authorize Requests

An endpoint requiring the user to authenticate, which redirects back to the client with an authorization code.

methods:

handleAuthorizeRequest

• Receives a request object for an authorize request, returns a response object with the appropriate response

validateAuthorizeRequest

• Receives a request object, returns false if the incoming request is not a valid Authorize Request. If the request is valid, returns an array of retrieved client details together with input. Applications should call this before displaying a login or authorization form to the user

Token Requests

An endpoint which the client uses to exchange the authorization code for an access token.

methods:

grantAccessToken

• Receives a request object for a token request, returns a token if the request is valid.

handleTokenRequest

• Receives a request object for a token request, returns a response object for the appropriate response.

Resource Requests

Any API method requiring oauth2 authentication. The server will validate the incomming request, and then allow the application to serve back the protected resource.

methods:

verifyResourceRequest

• Receives a request object for a resource request, finds the token if it exists, and returns a Boolean for whether the incomming request is valid

getAccessTokenData

• Takes a token string as an argument and returns the token data if applicable, or null if the token is invalid

The Response Object

The response object serves the purpose of making your server OAuth2 compliant. It will set the appropriate status codes, headers, and response body for a valid or invalid oauth request. To use it as it's simplest level, just send the output and exit:

$request = OAuth2_Request::createFromGlobals();
$response = new OAuth2_Response();

// will set headers, status code, and json response appropriately for success or failure
$server->grantAccessToken($request, $response);
$response->send();

The response object can also be used to customize output. Below, if the request is NOT valid, the error is sent to the browser:

if (!$token = $server->grantAccessToken($request, $response)) {
    $response->send();
    die();
}
echo sprintf('Your token is %s!!', $token);

This will populate the appropriate error headers, and return a json error response. If you do not want to send a JSON response, the response object can be used to display the information in any other format:

if (!$token = $server->grantAccessToken($request, $response)) {
    $parameters = $response->getParameters();
    // format as XML
    header("HTTP/1.1 " . $response->getStatusCode());
    header("Content-Type: text/xml");
    echo "<error><name>".$parameters['error']."</name><message>".$parameters['error_description']."</message></error>";
}

This is very useful when working in a framework or existing codebase, where this library will not have full control of the response.

Scope

####Configure your Scope

The use of Scope in an OAuth2 application is often key to proper permissioning. Scope is used to limit the authorization granted to the client by the resource owner. The most popular use of this is Facebook's ability for users to authorize a variety of different functions to the client ("access basic information", "post on wall", etc).

In this library, scope is handled by implementing OAuth2_Storage_ScopeInterface. This can be done using your own implementation, or by taking advantage of the existing OAuth2_Storage_Memory class:

// configure your available scopes
$defaultScope = 'basic';
$supportedScopes = array(
  'basic',
  'postonwall',
  'accessphonenumber'
);
$memory = new OAuth2_Storage_Memory(array(
  'default_scope' => $defaultScope,
  'supported_scopes' => $supportedScopes
));
$scopeUtil = new OAuth2_Scope($memory);

$server->setScopeUtil($scopeUtil);

This is the simplest way, but scope can by dynamically configured as well:

// configure your available scopes
$doctrine = Doctrine_Core::getTable('OAuth2Scope');
$scopeUtil = new OAuth2_Scope($doctrine);

$server->setScopeUtil($scopeUtil);

This example assumes the class being used implements OAuth2_Storage_ScopeInterface:

class OAuth2ScopeTable extends Doctrine_Table implements OAuth2_Storage_ScopeInterface
{
    public function getDefaultScope()
    {
        //...
    }

    public function scopeExists($scope, $client_id = null)
    {
        //...
    }
}

####Validate your scope

Configuring your scope in the server class will ensure requested scopes by the client are valid. However, there are two steps required to ensure the proper validation of your scope. First, the requested scope must be exposed to the resource owner upon authorization. In this library, this is left 100% to the implementation. The UI or whathaveyou must make clear the scope of the authorization being granted. Second, the resource request itself must specify what scope is required to access it:

// https://api.example.com/resource-requiring-postonwall-scope
$request = OAuth2_Request::createFromGlobals();
$response = new OAuth2_Response();
$scopeRequired = 'postonwall'; // this resource requires "postonwall" scope
if (!$server->verifyResourceRequest($request, $response, $scopeRequired)) {
  // if the scope required is different from what the token allows, this will send a "401 insufficient_scope" error
  $response->send();
}

####Customizing your scope

As the implementation of "scope" can be significantly different for each application, providing a different class other than OAuth2_Scope can be beneficial. Implement OAuth2_ScopeInterface in a custom class to fully customize.

Acknowledgements

This library is largely inspired and modified from Quizlet's OAuth2 PHP library

Contact

The best way to get help and ask questions is to file an issue. This will help answer questions for others as well.

If for whatever reason filing an issue does not make sense, contact Brent Shaffer (bshafs gmail com)