Simple Keycloak Guard for Laravel / Lumen

This package helps you authenticate users on a Laravel API based on JWT tokens generated from Keycloak Server.

Requirements

✔️ I`m building an API with Laravel.

✔️ I will not use Laravel Passport for authentication, because Keycloak Server will do the job.

✔️ The frontend is a separated project.

✔️ The frontend users authenticate directly on Keycloak Server to obtain a JWT token. This process have nothing to do with the Laravel API.

✔️ The frontend keep the JWT token from Keycloak Server.

✔️ The frontend make requests to the Laravel API, with that token.

💔 If your app does not match requirements, probably you are looking for https://socialiteproviders.com/Keycloak or https://github.com/Vizir/laravel-keycloak-web-guard

The flow

1. The frontend user authenticates on Keycloak Server

2. The frontend user obtains a JWT token.

3. In another moment, the frontend user makes a request to some protected endpoint on a Laravel API, with that token.

4. The Laravel API (through Keycloak Guard) handle it.

   • Verify token signature.
   • Verify token structure.
   • Verify token expiration time.
   • Verify if my API allows resource access from token.

5. If everything is ok, find the user on database and authenticate it on my API.

6. Optionally, the user can be created / updated in the API users database.

7. Return response

Install

Laravel / Lumen

Require the package

composer require robsontenorio/laravel-keycloak-guard

Lumen only

Register the provider in your boostrap app file bootstrap/app.php

Add the following line in the "Register Service Providers" section at the bottom of the file.

$app->register(\KeycloakGuard\KeycloakGuardServiceProvider::class);

For facades, uncomment $app->withFacades(); in your boostrap app file bootstrap/app.php

Configuration

Keycloak Guard

The Keycloak Guard configuration can be handled from Laravel .env file. ⚠️ Be sure all strings are trimmed.

Optionally you can publish the config file.

php artisan vendor:publish  --provider="KeycloakGuard\KeycloakGuardServiceProvider"

<?php

return [  
  'realm_public_key' => env('KEYCLOAK_REALM_PUBLIC_KEY', null),

  'load_user_from_database' => env('KEYCLOAK_LOAD_USER_FROM_DATABASE', true),
    
  'user_provider_custom_retrieve_method' => null,

  'user_provider_credential' => env('KEYCLOAK_USER_PROVIDER_CREDENTIAL', 'username'),

  'token_principal_attribute' => env('KEYCLOAK_TOKEN_PRINCIPAL_ATTRIBUTE', 'preferred_username'),

  'append_decoded_token' => env('KEYCLOAK_APPEND_DECODED_TOKEN', false),

  'allowed_resources' => env('KEYCLOAK_ALLOWED_RESOURCES', null)
];

✔️ realm_public_key

Required.

The Keycloak Server realm public key (string).

How to get realm public key? Click on "Realm Settings" > "Keys" > "Algorithm RS256" Line > "Public Key" Button

✔️ load_user_from_database

Required. Default is true.

If you do not have an users table you must disable this.

It fetchs user from database and fill values into authenticated user object. If enabled, it will work together with user_provider_credential and token_principal_attribute.

✔️ user_provider_custom_retrieve_method

Default is null.

If you have an users table and want it to be updated (creating or updating users) based on the token, you can inform a custom method on a custom UserProvider, that will be called instead retrieveByCredentials and will receive the complete decoded token as parameter, not just the credentials (as default).
This will allow you to customize the way you want to interact with your database, before matching and delivering the authenticated user object, having all the information contained in the (valid) access token available. To read more about custom UserProviders, please check Laravel's documentation about.

If using this feature, obviously, values defined for user_provider_credential and token_principal_attribute will be ignored.

✔️ user_provider_credential

Required. Default is username.

The field from "users" table that contains the user unique identifier (eg. username, email, nickname). This will be confronted against token_principal_attribute attribute, while authenticating.

✔️ token_principal_attribute

Required. Default is preferred_username.

The property from JWT token that contains the user identifier. This will be confronted against user_provider_credential attribute, while authenticating.

✔️ append_decoded_token

Default is false.

Appends to the authenticated user the full decoded JWT token ($user->token). Useful if you need to know roles, groups and other user info holded by JWT token. Even choosing false, you can also get it using Auth::token(), see API section.

✔️ allowed_resources

Required

Usually you API should handle one resource_access. But, if you handle multiples, just use a comma separated list of allowed resources accepted by API. This attribute will be confronted against resource_access attribute from JWT token, while authenticating.

Laravel Auth

Changes on config/auth.php

...
'defaults' => [
        'guard' => 'api', # <-- For sure, i`m building an API
        'passwords' => 'users',
    ],
    
    ....
    
    'guards' => [
        'api' => [
            'driver' => 'keycloak', # <-- Set the API guard driver to "keycloak"
            'provider' => 'users',
        ],
    ],

Laravel Routes

Just protect some endpoints on routes/api.php and you are done!

// public endpoints
Route::get('/hello', function () {
    return ':)';
});

// protected endpoints
Route::group(['middleware' => 'auth:api'], function () {
    Route::get('/protected-endpoint', 'SecretController@index');
    // more endpoints ...
});

Lumen Routes

Just protect some endpoints on routes/web.php and you are done!

// public endpoints
$router->get('/hello', function () {
    return ':)';
});

// protected endpoints
$router->group(['middleware' => 'auth'], function () {
    $router->get('/protected-endpoint', 'SecretController@index');
    // more endpoints ...
});

API

Simple Keycloak Guard implements Illuminate\Contracts\Auth\Guard. So, all Laravel default methods will be available. Ex: Auth::user() returns the authenticated user.

Default methods:

• check()
• guest()
• user()
• id()
• validate()
• setUser()

Keycloak Guard methods:

• token()

Ex: Auth::token() returns full decoded JWT token from authenticated user

• hasRole('some-resource', 'some-role'): Check if the authenticated user has especific role into a resource.

Ex: Whit this payload:

'resource_access' => [
  'myapp-backend' => [
      'roles' => [
        'myapp-backend-role1',
        'myapp-backend-role2'
      ]
  ],
  'myapp-frontend' => [
    'roles' => [
      'myapp-frontend-role1',
      'myapp-frontend-role2'
    ]
  ]
]

Auth::hasRole('myapp-backend', 'myapp-backend-role1') // true
Auth::hasRole('myapp-frontend', 'myapp-frontend-role1') // true
Auth::hasRole('myapp-backend', 'myapp-frontend-role1') // false

Contact

Twitter @robsontenorio