Zf-OAuth2

ZF2 module for OAuth2 authentication.

This module uses the oauth2-server-php library by Brent Shaffer to provide OAuth2 support.

Requirements

Please see the composer.json file.

Installation

You can install using:

$ composer require zfcampus/zf-oauth2

If you are using ext/mongodb, you will also need to install a compatibility package:

$ composer require alcaeus/mongo-php-adapter

Finally, you will need to add the following modules to your application's configuration:

'modules' => [
    /* ... */
    'ZF\ApiProblem',
    'ZF\ContentNegotiation',
    'ZF\OAuth2',
],

zf-component-installer

If you use zf-component-installer, that plugin will install zf-oauth2 and its other Apigility dependencies as modules for you.

Configuration

This module uses any PDO-suported database to manage the OAuth2 information (users, client, token, etc). The database structure is stored in data/db_oauth2.sql.

CREATE TABLE oauth_clients (
    client_id VARCHAR(80) NOT NULL,
    client_secret VARCHAR(80) NOT NULL,
    redirect_uri VARCHAR(2000) NOT NULL,
    grant_types VARCHAR(80),
    scope VARCHAR(2000),
    user_id VARCHAR(255),
    CONSTRAINT clients_client_id_pk PRIMARY KEY (client_id)
);
CREATE TABLE oauth_access_tokens (
    access_token VARCHAR(40) NOT NULL,
    client_id VARCHAR(80) NOT NULL,
    user_id VARCHAR(255),
    expires TIMESTAMP NOT NULL,
    scope VARCHAR(2000),
    CONSTRAINT access_token_pk PRIMARY KEY (access_token)
);
CREATE TABLE oauth_authorization_codes (
    authorization_code VARCHAR(40) NOT NULL,
    client_id VARCHAR(80) NOT NULL,
    user_id VARCHAR(255),
    redirect_uri VARCHAR(2000),
    expires TIMESTAMP NOT NULL,
    scope VARCHAR(2000),
    id_token VARCHAR(2000),
    CONSTRAINT auth_code_pk PRIMARY KEY (authorization_code)
);
CREATE TABLE oauth_refresh_tokens (
    refresh_token VARCHAR(40) NOT NULL,
    client_id VARCHAR(80) NOT NULL,
    user_id VARCHAR(255),
    expires TIMESTAMP NOT NULL,
    scope VARCHAR(2000),
    CONSTRAINT refresh_token_pk PRIMARY KEY (refresh_token)
);
CREATE TABLE oauth_users (
    username VARCHAR(255) NOT NULL,
    password VARCHAR(2000),
    first_name VARCHAR(255),
    last_name VARCHAR(255),
    CONSTRAINT username_pk PRIMARY KEY (username)
);
CREATE TABLE oauth_scopes (
    type VARCHAR(255) NOT NULL DEFAULT "supported",
    scope VARCHAR(2000),
    client_id VARCHAR (80),
    is_default SMALLINT DEFAULT NULL
);
CREATE TABLE oauth_jwt (
    client_id VARCHAR(80) NOT NULL,
    subject VARCHAR(80),
    public_key VARCHAR(2000),
    CONSTRAINT jwt_client_id_pk PRIMARY KEY (client_id)
);

PostgreSQL

We also have a PostgreSQL-specific DDL in data/db_oauth2_postgresql.sql.

For security reasons, we encrypt the fields client_secret (table oauth_clients) and password (table oauth_users) using the bcrypt algorithm (via the class Zend\Crypt\Password\Bcrypt).

In order to configure the zf-oauth2 module for database access, you need to copy the file config/oauth2.local.php.dist to config/autoload/oauth2.local.php in your ZF2 application, and edit it to provide your DB credentials (DNS, username, password).

We also include a SQLite database in data/dbtest.sqlite that you can use in a test environment. In this database, you will find a test client account with the client_id "testclient" and the client_secret "testpass". If you want to use this database, you can configure your config/autoload/oauth2.local.php file as follow:

return array(
    'zf-oauth2' => array(
        'db' => array(
            'dsn' => 'sqlite:<path to zf-oauth2 module>/data/dbtest.sqlite',
        ),
    ),
);

Mongo Configuration

The Mongo OAuth2 adapter wraps the bshaffer adapter by adding the same password encryption as the rest of apigility. The collections needed are the same as above in the PDO adapter. To create an OAuth2 client, insert a document like the following into the oauth_clients collection:

{
    "client_id":     "testclient",
    "client_secret": "$2y$14$f3qml4G2hG6sxM26VMq.geDYbsS089IBtVJ7DlD05BoViS9PFykE2",
    "redirect_uri":  "/oauth/receivecode",
    "grant_types":   null
}

User ID Provider

When a user requests an authorization code they may provide their user_id as a request parameter to the /oauth/authorize route. This will store the user_id in the access_token, refresh_token, and authorization_code tables as the user goes throught the oauth2 process.

A user may be authenticated through Zend\Authentication\AuthenticationService or another authentication means. When a user must provide authentication before they may access the /oauth/authorize route, the authenticated user ID should be used. This is done with the service manager alias ZF\OAuth2\Provider\UserId.

The default User ID Provider uses the request query parameter user_id and is handled via the class ZF\OAuth2\Provider\UserId\Request.

Provided with this repository is an alternative provider, ZF\OAuth2\Provider\UserId\AuthorizationService, which uses Zend\Authentication\AuthenticationService to fetch the identity. To change the User ID Provider to use this service, change the ZF\OAuth2\Provider\UserId service alias to point at it:

return array(
    'service_manager' => 
        'aliases' => array(
            'ZF\OAuth2\Provider\UserId' => 'ZF\OAuth2\Provider\UserId\AuthenticationService',
        ),
    ),
);

How to test OAuth2

To test the OAuth2 module, you have to add a client_id and a client_secret into the oauth2 database. If you are using the SQLite test database, you don't need to add a client_id; just use the default "testclient"/"testpass" account.

Because we encrypt the password using the bcrypt algorithm, you need to encrypt the password using the Zend\Crypt\Password\Bcrypt class from Zend Framework 2. We provided a simple script in /bin/bcrypt.php to generate the hash value of a user's password. You can use this tool from the command line, with the following syntax:

php bin/bcrypt.php testpass

where "testpass" is the user's password that you want to encrypt. The output of the previous command will be the hash value of the user's password, a string of 60 bytes like the following:

$2y$14$f3qml4G2hG6sxM26VMq.geDYbsS089IBtVJ7DlD05BoViS9PFykE2

After the generation of the hash value of the password (client_secret), you can add a new client_id in the database using the following SQL statement:

INSERT INTO oauth_clients (
    client_id,
    client_secret,
    redirect_uri)
VALUES (
    "testclient",
    "$2y$14$f3qml4G2hG6sxM26VMq.geDYbsS089IBtVJ7DlD05BoViS9PFykE2",
    "/oauth/receivecode"
);

To test the OAuth2 module, you can use an HTTP client like HTTPie or CURL. The examples below use HTTPie and the test account "testclient"/"testpass".

REQUEST TOKEN (client_credentials)

You can request an OAuth2 token using the following HTTPie command:

http --auth testclient:testpass -f POST http://<URL of your ZF2 app>/oauth grant_type=client_credentials

This POST requests a new token to the OAuth2 server using the client_credentials mode. This is typical in machine-to-machine interaction for application access. If everything works fine, you should receive a response like this:

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

Security note: because this POST uses basic HTTP authentication, the client_secret is exposed in plaintext in the HTTP request. To protect this call, a TLS/SSL connection is required.

AUTHORIZE (code)

If you have to integrate an OAuth2 service with a web application, you need to use the Authorization Code grant type. This grant requires an approval step to authorize the web application. This step is implemented using a simple form that requests the user approve access to the resource (account). This module provides a simple form to authorize a specific client. This form can be accessed by a browser using the following URL:

http://<URL of your ZF2 app>/oauth/authorize?response_type=code&client_id=testclient&redirect_uri=/oauth/receivecode&state=xyz

This page will render the form asking the user to authorize or deny the access for the client. If they authorize the access, the OAuth2 module will reply with an Authorization code. This code must be used to request an OAuth2 token; the following HTTPie command provides an example of how to do that:

http --auth testclient:testpass -f POST http://<URL of your ZF2 app>/oauth grant_type=authorization_code&code=YOUR_CODE&redirect_uri=/oauth/receivecode

In client-side scenarios (i.e mobile) where you cannot store the Client Credentials in a secure way, you cannot use the previous workflow. In this case we can use an implicit grant. This is similar to the authorization code, but rather than an authorization code being returned from the authorization request, a token is returned.

To enable the module to accept the implicit grant type, you need to change the configuration of allow_implicit to true in the config/autoload/oauth2.local.php file:

return array(
    'zf-oauth2' => array(
        // ...
        'allow_implicit' => true,
        // ...
    ),
);

To request a token from the client side, you need to request authorization via the OAuth2 server:

http://<URL of your ZF2 app>/oauth/authorize?response_type=token&client_id=testclient&redirect_uri=/oauth/receivecode&state=xyz

This request will render the authorization form as in the previous example. If you authorize the access, the request will be redirected to /oauth/receivecode (as provided in the redirect_uri parameter in the above example), with the access_token specified in the URI fragment, per the following sample:

/oauth/receivecode#access_token=559d8f9b6bedd8d94c8e8d708f87475f4838c514&expires_in=3600&token_type=Bearer&state=xyz

To get the access_token, you can parse the URI. We used the URI fragment to pass the access_token because in this way the token is not transmitted to the server; it will available only to the client.

In JavaScript, you can easily parse the URI with this snippet of code:

// function to parse fragment parameters
var parseQueryString = function( queryString ) {
    var params = {}, queries, temp, i, l;

    // Split into key/value pairs
    queries = queryString.split("&");

    // Convert the array of strings into an object
    for ( i = 0, l = queries.length; i < l; i++ ) {
        temp = queries[i].split('=');
        params[temp[0]] = temp[1];
    }
    return params;
};

// get token params from URL fragment
var tokenParams = parseQueryString(window.location.hash.substr(1));

REVOKE (code)

Starting with version 1.4.0, you can revoke access tokens. By default, revocation happens via a POST request to the path /oauth/revoke, which expects a payload with:

• token, the OAuth2 access token to revoke.
• token_type_hint => 'access_token', indicating that an access token is being revoked.

The payload may be delivered as application/x-www-form-urlencoded or as JSON.

Access a test resource

When you obtain a valid token, you can access a restricted API resource. The OAuth2 module is shipped with a test resource that is accessible with the URL /oauth/resource. This is a simple resource that returns JSON data.

To access the test resource, you can use the following HTTPie command:

http -f POST http://<URL of your ZF2 app>/oauth/resource access_token=000ab5afab4cbbbda803fb9e50e7943f5e766748
# or
http http://<<URL of your ZF2 app>/oauth/resource "Authorization:Bearer 000ab5afab4cbbbda803fb9e50e7943f5e766748"

As you can see, the OAuth2 module supports the data either via POST, using the access_token value, or using the Bearer authorization header.

How to protect your API using OAuth2

You can protect your API using the following code (for instance, at the top of a controller):

if (!$this->server->verifyResourceRequest(OAuth2Request::createFromGlobals())) {
    // Not authorized return 401 error
    $this->getResponse()->setStatusCode(401);
    return;
}

where $this->server is an instance of OAuth2\Server (see the AuthController.php).