This quickstart covers building an API protected by an Auth0-issued access token. This type of API is typically consumed by:

• Mobile, desktop, and other native applications using the Native login flow
• CLIs, daemons, or services running on your back-end using the Client Credentials Flow

If this API is only consumed by a web application on the same domain (in the case of AJAX actions or lazy loading content for an authenticated user) then the API protection should be handled by the application itself and the login flow secured by Auth0.

Protecting your Laravel API requires a middleware which will check for and verify a bearer token in the Authorization header of an incoming HTTP request. We'll do that using tools provided by the Auth0 Laravel package.

$ composer require auth0/login

The laravel-auth0 plugin comes with a configuration file that can be generated using Artisan. First, generate the configuration file from the command line:

$ php artisan vendor:publish --provider "Auth0\Login\LoginServiceProvider"

After the file is generated, it will be located at config/laravel-auth0.php. Edit this file to add the configuration values needed to verify incoming tokens:

// config/laravel-auth0.php
return [
	// ...
	'authorized_issuers' => [ 'https://your-tenant.auth0.com/' ],
	// ...
	'api_identifier' => 'https://quickstarts/api',
	// ...
	'supported_algs' => [ 'RS256' ],
	// ...
];

In more detail:

• authorized_issuers is an array of allowed token issuers. In this case, it would simply be an array with just your tenant URL.
• api_identifier is the Identifier field of the API created above.
• supported_algs is the Signing Algorithm field of the API created above. This value should be an array but only have a single value, RS256.

By default, Apache does not parse Authorization headers from incoming HTTP requests. You may need to add the following to the .htaccess file for your application:

RewriteEngine On
RewriteCond %{HTTP:Authorization} ^(.*)
RewriteRule .* - [e=HTTP_AUTHORIZATION:%1]

For the two private API routes, we'll need a middleware to check for a bearer token in an Authorization header for the request and then verify that the token is valid. We'll create that middleware using the make:middleware Artisan command:

php artisan make:middleware CheckJWT

Now, let's implement the handle() method that Laravel will call automatically for the route:

<?php
// app/Http/Middleware/CheckJWT.php

namespace App\Http\Middleware;

use Closure;
use Auth0\SDK\JWTVerifier;

class CheckJWT
{

    /**
     * Validate an incoming JWT access token.
     *
     * @param \Illuminate\Http\Request $request - Illuminate HTTP Request object.
     * @param Closure $next - Function to call when middleware is complete.
     *
     * @return mixed
     */
    public function handle($request, Closure $next) {
        $accessToken = $request->bearerToken();
        if (empty($accessToken)) {
            return response()->json(['message' => 'Bearer token missing'], 401);
        }

        $laravelConfig = config('laravel-auth0');
        $jwtConfig = [
            'authorized_iss' => $laravelConfig['authorized_issuers'],
            'valid_audiences' => [$laravelConfig['api_identifier']],
            'supported_algs' => $laravelConfig['supported_algs'],
        ];

        try {
            $jwtVerifier = new JWTVerifier($jwtConfig);
            $decodedToken = $jwtVerifier->verifyAndDecode($accessToken);
        } catch (\Exception $e) {
            return response()->json(['message' => $e->getMessage()], 401);
        }

        return $next($request);
    }
}

This middleware:

• Checks that there is a Bearer token and stops the request if one was not found.
• Pulls in the configuration values needed to verify the token.
• Attempts to decode the token, catching any exceptions thrown if it is expired, malformed, or otherwise invalid.

Next, we register this middleware we in the HTTP Kernel with the name jwt:

// app/Http/Kernel.php
// ...
class Kernel extends HttpKernel {
	// ...
	protected $routeMiddleware = [
	    // ...
	    'jwt' => \App\Http\Middleware\CheckJWT::class,
	    // ...
	];
	// ...
}

We are now able to protect individual API endpoints by applying the jwt middleware:

// routes/api.php

// This endpoint does not need authentication.
Route::get('/public', function (Request $request) {
    return response()->json(['message' => 'Hello from a public endpoint!']);
});

// These endpoints require a valid access token.
Route::middleware(['jwt'])->group(function () {
    Route::get('/private', function (Request $request) {
        return response()->json(['message' => 'Hello from a private endpoint!']);
    });
});

The /api/private route is now only accessible if a valid access token is included in the Authorization header of the incoming request. We can test this by manually generating an access token for the API and using a tool like Postman to test the routes.

In the Auth0 Dashboard, go to the Test tab for the API created above and click the COPY TOKEN link.

Now, let's turn on the Laravel test server:

$ php artisan serve --port=3010

Send a GET request to the public route - http://localhost:3010/api/public - and you should receive back:

{ "message": "Hello from a public endpoint!" }

Now send a GET request to the private route - http://localhost:3010/api/private - and you should get a 401 status and the following message:

{ "message": "Bearer token missing" }

Add an Authorization header set to Bearer API_TOKEN_HERE using the token generated above. Send the GET request to the private route again and you should see:

{ "message": "Hello from a private endpoint!" }

The middleware we created above checks for the existence and validity of an access token but does not check the scope of the token. In this section, we will modify the middleware created above to check for specific scopes.

Then, in the existing CheckJWT class, make the following changes:

// app/Http/Middleware/CheckJWT.php
// ...
class CheckJWT {
    // Add the new parameter to this method.
    public function handle ($request, Closure $next, $scopeRequired = null) {
        // Existing code minus the return statement stays here ...
        // ...
        if ($scopeRequired && !$this->tokenHasScope($decodedToken, $scopeRequired)) {
            return response()->json(['message' => 'Insufficient scope'], 403);
        }

        // Return statement is unchanged.
        return $next($request);
    }

    /**
     * Check if a token has a specific scope.
     *
     * @param \stdClass $token - JWT access token to check.
     * @param string $scopeRequired - Scope to check for.
     *
     * @return bool
     */
    protected function tokenHasScope($token, $scopeRequired) {
        if (empty($token->scope)) {
            return false;
        }

        $tokenScopes = explode(' ', $token->scope);
        return in_array($scopeRequired, $tokenScopes);
    }
}

In summary:

• We added a $scopeRequired parameter to the handle() method with a default value of null. This will allow us to still handle private routes that do not need to check scope.
• At the end of handle(), we check if the route requires a scope and, if so, that the token includes it.
• We added a tokenHasScope() method to look for a specific scope within a decoded token.

Now, we can create a new middleware group that will check for both a valid token and a specific scope:

// routes/api.php
// ...

// These endpoints require a valid access token with a "read:messages" scope.
Route::middleware(['jwt:read:messages'])->group(function () {
    Route::get('/private-scoped', function (Request $request) {
        return response()->json(['message' => 'Hello from a private, scoped endpoint!']);
    });
});

This route is now only accessible if an access token used in the request has a scope of read:messages.

To test this route, first send a GET request with no token to the private, scoped route - http://localhost:3010/api/private-scoped - and you should get a 401 status and the following message:

{ "message": "Bearer token missing" }

Add an Authorization header set to Bearer API_TOKEN_HERE using the same token from the previous section. Send the GET request to the private, scoped route again and you should get a 403 status and the following message:

{ "message": "Insufficient scope" }

Back in the Auth0 Dashboard:

1. Go to the Machine to Machine Applications tab for the API created above.
2. Scroll to the test Application for this API, make sure it's authorized, and click the down arrow icon.
3. Add the read:messages scope and click Update (then Continue if needed).

4. Click the Test tab, select the test Application, and click the COPY TOKEN link above the second code block.

Change the Authorization header to use the new token and send the GET request again. You should get a 200 status and the following message:

{ "message": "Hello from a private, scoped endpoint!" }

The example above uses manually-generated tokens which are not long-lived. Once your API is live on the web and ready to accept requests, the applications making the requests will need to get an access token for this API using one of a few ways:

• Web applications will use the Authorization Code Flow
• Mobile, desktop, and other native applications will use a Mobile/Native Login Flow
• CLIs, daemons, or services running on your back-end will use an Machine-to-Machine Flow

Regardless of the type, the application will need to request the audience of this API during the login flow to receive a correctly-formed access token.

To configure CORS, you should add the laravel-cors dependency. You can check it out here.

After installation, add HandleCors middleware in the application's global middleware stack:

// app/Http/Kernel.php
protected $middleware = [
    // ...
    \Barryvdh\Cors\HandleCors::class,
];

Add the following to the configuration file for CORS:

<?php
// config/cors.php
return [
    'supportsCredentials' => true,
    'allowedOrigins' => ['http://localhost:3000'],
    'allowedOriginsPatterns' => [],
    'allowedHeaders' => ['*'],
    'allowedMethods' => ['*'],
    'exposedHeaders' => [],
    'maxAge' => 0,
];