3. Servers and Schemas

Introduction

In this chapter, we are going to:

• install the Laravel JSON:API package;
• create our JSON:API server; and
• create our first JSON:API resource - the posts resource.

At the end of this chapter, you'll be able to retrieve a posts resource from the API.

Installing Laravel JSON:API

To start, we'll need to install the Laravel JSON:API package into our application, via Composer. Run the following commands:

vendor/bin/sail composer require laravel-json-api/laravel
vendor/bin/sail composer require --dev laravel-json-api/testing

We then need to publish the Laravel JSON:API configuration file, using the following command:

vendor/bin/sail artisan vendor:publish --provider="LaravelJsonApi\Laravel\ServiceProvider"

This will create a config/jsonapi.php file.

Exception Handler

There's one final setup step. Laravel JSON:API needs to ensure that your API returns errors in the JSON:API format. To do this, we need to add a few things to our application's exception handler.

Open the file app/Exceptions/Handler.php and you'll see the default exception handler that Laravel created for our application. Make the following changes:

 namespace App\Exceptions;

 use Illuminate\Foundation\Exceptions\Handler as ExceptionHandler;
+use LaravelJsonApi\Core\Exceptions\JsonApiException;
+use LaravelJsonApi\Exceptions\ExceptionParser;
 use Throwable;

 class Handler extends ExceptionHandler
 {
+    /**
+     * A list of the exception types that are not reported.
+     *
+     * @var array
+     */
+    protected $dontReport = [
+       JsonApiException::class,
+    ];

     /**
      * A list of the inputs that are never flashed for validation exceptions.
      *
      * @var array
      */
     protected $dontFlash = [
         'current_password',
         'password',
         'password_confirmation',
     ];

     /**
      * Register the exception handling callbacks for the application.
      *
      * @return void
      */
     public function register()
     {
         $this->reportable(function (Throwable $e) {
             //
         });
+
+        $this->renderable(
+            ExceptionParser::make()->renderable()
+        );
     }
 }

The change in the register() method takes care of converting exceptions to the JSON:API format, if the client has requested JSON:API content via the application/vnd.api+json media type.

Creating a JSON:API Server

Laravel JSON:API allows you to create multiple JSON:API servers within you application. In this tutorial we're going to create a single server, which we'll call v1.

Run the following command to create your first server:

vendor/bin/sail artisan jsonapi:server v1

This creates a new file in your application: app/JsonApi/V1/Server.php. This is the class that contains the configuration for your JSON:API server. It looks like this:

namespace App\JsonApi\V1;

use LaravelJsonApi\Core\Server\Server as BaseServer;

class Server extends BaseServer
{

    /**
     * The base URI namespace for this server.
     *
     * @var string
     */
    protected string $baseUri = '/api/v1';

    /**
     * Bootstrap the server when it is handling an HTTP request.
     *
     * @return void
     */
    public function serving(): void
    {
        // no-op
    }

    /**
     * Get the server's list of schemas.
     *
     * @return array
     */
    protected function allSchemas(): array
    {
        return [
            // @TODO
        ];
    }
}

It's worth noting at this point that the $baseUri property is set to /api/v1. This means all the HTTP requests we send to our API will start with http://localhost/api/v1/.

There's one thing we need to do at this point: we need to tell Laravel JSON:API that we have a v1 server. To do that, we need to edit our config/jsonapi.php configuration file. If you open that file, it looks like this:

return [

    /*
    |--------------------------------------------------------------------------
    | Root Namespace
    |--------------------------------------------------------------------------
    |
    | The root JSON:API namespace, within your application's namespace.
    | This is used when generating any class that does not sit *within*
    | a server's namespace. For example, new servers and filters.
    |
    | By default this is set to `JsonApi` which means the root namespace
    | will be `\App\JsonApi`, if your application's namespace is `App`.
    */
    'namespace' => 'JsonApi',

    /*
    |--------------------------------------------------------------------------
    | Servers
    |--------------------------------------------------------------------------
    |
    | A list of the JSON:API compliant APIs in your application, referred to
    | as "servers". They must be listed below, with the array key being the
    | unique name for each server, and the value being the fully-qualified
    | class name of the server class.
    */
    'servers' => [
//        'v1' => \App\JsonApi\V1\Server::class,
    ],
];

To add our server, we just need to uncomment the line in the servers part of the configuration. Do that now, so that your configuration looks like this:

 'servers' => [
-//  'v1' => \App\JsonApi\V1\Server::class,
+    'v1' => \App\JsonApi\V1\Server::class,
 ],

And that's it! We now have a JSON:API server. Next we need to add our first resource: the posts resource.

The Post Schema

Laravel JSON:API uses Nova-style classes called Schemas to define the resources in an API. In JSON:API, resources refer to the objects that can be created, read, updated and deleted in your API. Our blog application will have the following resources:

• posts
• users
• comments
• tags

Hopefully you recognise those names - they match the models we created in our application.

In this chapter, we'll create just the schema for our Post model, and read the resource from our API to check it's working.

Creating the Schema

To create our schema, run the following command:

vendor/bin/sail artisan jsonapi:schema posts

This creates a new file, app/JsonApi/V1/Posts/PostSchema.php, which looks like this:

namespace App\JsonApi\V1\Posts;

use App\Models\Post;
use LaravelJsonApi\Eloquent\Contracts\Paginator;
use LaravelJsonApi\Eloquent\Fields\DateTime;
use LaravelJsonApi\Eloquent\Fields\ID;
use LaravelJsonApi\Eloquent\Filters\WhereIdIn;
use LaravelJsonApi\Eloquent\Pagination\PagePagination;
use LaravelJsonApi\Eloquent\Schema;

class PostSchema extends Schema
{

    /**
     * The model the schema corresponds to.
     *
     * @var string
     */
    public static string $model = Post::class;

    /**
     * Get the resource fields.
     *
     * @return array
     */
    public function fields(): array
    {
        return [
            ID::make(),
            DateTime::make('createdAt')->sortable()->readOnly(),
            DateTime::make('updatedAt')->sortable()->readOnly(),
        ];
    }

    /**
     * Get the resource filters.
     *
     * @return array
     */
    public function filters(): array
    {
        return [
            WhereIdIn::make($this),
        ];
    }

    /**
     * Get the resource paginator.
     *
     * @return Paginator|null
     */
    public function pagination(): ?Paginator
    {
        return PagePagination::make();
    }

}

Our new PostSchema class defines the posts resource, which is the JSON:API representation of the Post model - notice how that is defined on the the static $model property of the class.

Now we've created the schema, we need to tell our JSON:API server that the schema exists. To do this, we update the allSchemas() method in our app/JsonApi/Server.php file. Update that to look like this:

 /**
  * Get the server's list of schemas.
  *
  * @return array
  */
 protected function allSchemas(): array
 {
     return [
-        // @TODO
+        Posts\PostSchema::class,
     ];
 }

Schema Fields

The fields() method on the schema defines the attributes and relationships that our resource has. Notice the created file has a few standard fields in it already: the ID field for the resource, and the createdAt and updatedAt dates that are standard on an Eloquent model.

Our Post model has a few more attributes than that. Hopefully you remember that the database table had content, published_at, slug and title columns. We want to add these to our PostSchema as these values should be shown in our API. To do that, we make the following changes to our class:

 namespace App\JsonApi\V1\Posts;

 use App\Models\Post;
 use LaravelJsonApi\Eloquent\Contracts\Paginator;
+use LaravelJsonApi\Eloquent\Fields\DateTime;
 use LaravelJsonApi\Eloquent\Fields\ID;
+use LaravelJsonApi\Eloquent\Fields\Str;
 use LaravelJsonApi\Eloquent\Filters\WhereIdIn;
 use LaravelJsonApi\Eloquent\Pagination\PagePagination;
 use LaravelJsonApi\Eloquent\Schema;

 class PostSchema extends Schema
 {

     /**
      * The model the schema corresponds to.
      *
      * @var string
      */
     public static string $model = Post::class;

     /**
      * Get the resource fields.
      *
      * @return array
      */
     public function fields(): array
     {
         return [
             ID::make(),
+            Str::make('content'),
             DateTime::make('createdAt')->sortable()->readOnly(),
+            DateTime::make('publishedAt')->sortable(),
+            Str::make('slug'),
+            Str::make('title')->sortable(),
             DateTime::make('updatedAt')->sortable()->readOnly(),
         ];
     }

     /**
      * Get the resource filters.
      *
      * @return array
      */
     public function filters(): array
     {
         return [
             WhereIdIn::make($this),
         ];
     }

     /**
      * Get the resource paginator.
      *
      * @return Paginator|null
      */
     public function pagination(): ?Paginator
     {
         return PagePagination::make();
     }

 }

Fetching a Post Resource

When we ran our database seeder, we created a Post model in the database. As the primary key of this model is auto-incrementing, we know that first model will have an identifier of 1.

The JSON:API specification states that we should be able to fetch this post using the JSON:API type and id. Together, these two things uniquely identify the post in our API. The URL to do this will follow this format:

<HOST>/<API_NAMESPACE>/<TYPE>/<ID>

That means we can fetch our first post using the following URL:

http://localhost/api/v1/posts/1

When running this request, we need to specify the JSON:API media type in the Accept header - the media type is application/vnd.api+json. This means our HTTP request will look like this:

GET http://localhost/api/v1/posts/1 HTTP/1.1
Accept: application/vnd.api+json

Try this now. You should see the following response:

HTTP/1.0 404 Not Found
Content-Type: application/vnd.api+json

{
  "jsonapi": {
    "version": "1.0"
  },
  "errors": [
    {
      "status": "404",
      "title": "Not Found"
    }
  ]
}

This is a JSON:API error, with a 404 Not Found HTTP status - which tells us the /api/v1/posts/1 route does not exist. We'll need to add that now.

Routing

Laravel JSON:API makes it easy to register JSON:API routes for your server.

In Laravel applications, our API routing is defined in the routes/api.php file. If you open that file now, you will see:

use Illuminate\Http\Request;
use Illuminate\Support\Facades\Route;

/*
|--------------------------------------------------------------------------
| API Routes
|--------------------------------------------------------------------------
|
| Here is where you can register API routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| is assigned the "api" middleware group. Enjoy building your API!
|
*/

Route::middleware('auth:sanctum')->get('/user', function (Request $request) {
    return $request->user();
});

To add our JSON:API server's routes, we will use the JsonApiRoute facade. Update the routes/api.php file to look like this:

 use Illuminate\Http\Request;
 use Illuminate\Support\Facades\Route;
+use LaravelJsonApi\Laravel\Facades\JsonApiRoute;
+use LaravelJsonApi\Laravel\Http\Controllers\JsonApiController;
+use LaravelJsonApi\Laravel\Routing\ResourceRegistrar;

 Route::middleware('auth:sanctum')->get('/user', function (Request $request) {
     return $request->user();
 });
+
+JsonApiRoute::server('v1')->prefix('v1')->resources(function (ResourceRegistrar $server) {
+    $server->resource('posts', JsonApiController::class)->readOnly();
+});

The JsonApiRoute facade provides a fluent interface for defining the HTTP routes for your JSON:API server. The server() method tells it that we're defining routes for our v1 server.

On a default Laravel installation, the routes you define in the routes/api.php file already have the /api URL prefix. The prefix('v1') call above adds /v1 so that in total our API's URL prefix is /api/v1.

The closure that is passed to the resources() method receives a $server argument. This is a helper to make it easy to define the resource routes in the server. We've added the following:

$server->resource('posts', JsonApiController::class)->readOnly();

This adds the following routes:

• GET /api/v1/posts
• GET /api/v1/posts/<ID>

TIP

At the moment we're only adding read-only routes - i.e. GET routes. Later in the tutorial we'll add routes to create, update and delete post resources.

Try the HTTP request again:

GET http://localhost/api/v1/posts/1 HTTP/1.1
Accept: application/vnd.api+json

This time you'll see the following:

HTTP/1.1 401 Unauthorized
Content-Type: application/vnd.api+json

{
  "jsonapi": {
    "version": "1.0"
  },
  "errors": [
    {
      "detail": "Unauthenticated.",
      "status": "401",
      "title": "Unauthorized"
    }
  ]
}

This time we get a 401 Unauthorized HTTP status, which tells us that we need to add some logic to tell our server who can access the post resource. We'll add that now.

Authentication

Laravel JSON:API uses Laravel's policy implementation to authorise requests to the API. This means for our posts resource we need to create a PostPolicy. You can do this using the following Laravel command:

vendor/bin/sail artisan make:policy PostPolicy --model Post

This will create a app/Policies/PostPolicy.php file, which looks like this:

namespace App\Policies;

use App\Models\Post;
use App\Models\User;
use Illuminate\Auth\Access\HandlesAuthorization;

class PostPolicy
{
    use HandlesAuthorization;

    /**
     * Determine whether the user can view any models.
     *
     * @param  \App\Models\User  $user
     * @return \Illuminate\Auth\Access\Response|bool
     */
    public function viewAny(User $user)
    {
        //
    }

    /**
     * Determine whether the user can view the model.
     *
     * @param  \App\Models\User  $user
     * @param  \App\Models\Post  $post
     * @return \Illuminate\Auth\Access\Response|bool
     */
    public function view(User $user, Post $post)
    {
        //
    }

    // ...other policy methods
}

The view() method is where we need to put the logic for who can view a specific post in our blog. Make the following changes to the view() method:

 /**
  * Determine whether the user can view the model.
  *
- * @param  \App\Models\User  $user
+ * @param  \App\Models\User|null  $user
  * @param  \App\Models\Post  $post
  * @return \Illuminate\Auth\Access\Response|bool
  */
-public function view(User $user, Post $post)
+public function view(?User $user, Post $post)
 {
-    //
+    if ($post->published_at) {
+        return true;
+    }
+
+    return $user && $user->is($post->author);
 }

Notice we've made the $user argument nullable. This means the method will be called if there is no authenticated user.

Our logic says: if the post is published, anyone can see it. If it is not published (a draft post), there must be an authenticated user and they must be the author of the post.

This is a sensible approach for a blog application. We want anyone to see our published posts, but draft posts should only be visible to the author.

Fetching the Post

Now we added our authorization logic, we can retry our request:

GET http://localhost/api/v1/posts/1 HTTP/1.1
Accept: application/vnd.api+json

Success! This time you'll see the posts resource:

HTTP/1.1 200 OK
Content-Type: application/vnd.api+json

{
  "jsonapi": {
    "version": "1.0"
  },
  "links": {
    "self": "http:\/\/localhost\/api\/v1\/posts\/1"
  },
  "data": {
    "type": "posts",
    "id": "1",
    "attributes": {
      "content": "In our first blog post, you will learn all about Laravel JSON:API...",
      "createdAt": "2021-09-19T15:47:49.000000Z",
      "publishedAt": "2021-09-19T15:47:49.000000Z",
      "slug": "welcome-to-laravel-jsonapi",
      "title": "Welcome to Laravel JSON:API",
      "updatedAt": "2021-09-19T15:47:49.000000Z"
    },
    "links": {
      "self": "http:\/\/localhost\/api\/v1\/posts\/1"
    }
  }
}

In Summary

In this chapter, we created our JSON:API server and added our first resource to it by creating a PostSchema class. We also learnt how to register JSON:API routes and how authentication works.

In the next chapter, we'll add relationships to our posts resource.