Mocking API

Mocking API is a feature that allows your controller to send response with fake data.

When developing REST API with a team consisting of Back-end and Front-end Developers. Creating an API implementation could takes time. Sometimes it makes Front-end developer have to wait Back-end Developer to finish the implementation. This will make development time less efficient.

To make development time more efficient. We can use Mocking API so Front-end Developer can consume our API without waiting for real implementation to be done.

To do that, in Evo you can simply attach Emsifa\Evo\Http\Response\Mock attribute to your controller method. So when user call that endpoint, Evo will prevent its controller to be executed, instead Evo will read its return type, create return type instance and fill its properties with fake data, finally Evo will respond that fake instance.

Using Mock Attribute

For example, we will use ExampleController in Swagger UI section before.

To respond mock on postSomething method, we need to attach Emsifa\Evo\Http\Response\Mock like an example below:

<?php
namespace App\Http\Controllers;
use Illuminate\Http\Request;use Emsifa\Evo\Route\Post;use Emsifa\Evo\Route\RoutePrefix;use Emsifa\Evo\Http\Response\Mock;use App\Dtos\PostSomethingDto;use App\Http\Responses\PostSomethingResponse;
#[RoutePrefix('examples')]class ExampleController extends Controller{    #[Post('post-something')]    #[Mock]    public function postSomething(        #[Body] PostSomethingDto $dto    ): PostSomethingResponse    {        return PostSomethingResponse::fromArray($dto);    }}

That's it!

To try this, open your Swagger UI page. Expand POST /api/examples/post-something endpoint, click Try it out, then click execute.

You should see it responded with random data.

Using Specific Faker

Behind the scene Evo uses Faker to generate mock data. By default Evo choosing faker to be used is by looking the data type and the name of each property.

For example, if you have $name property, Evo will use $faker->name(). For $title property, Evo will use $faker->title(). For float $latitude, Evo will use $faker->latitude(). If the property name doesn't have related faker formatter available, Evo will choose faker formatter by it's data type.

If you want to use another faker instead of default choosed faker. You can use Emsifa\Evo\Dtos\UseFaker to define what formatter you want to use.

For example, we will use paragraphs(5, true) formatter to $message property.

Here is the code:

<?php
namespace App\Http\Responses;
use Emsifa\Evo\Dtos\UseFaker;use Emsifa\Evo\Http\Response\JsonResponse;
#[Description("Post something succeed")]class PostSomethingResponse extends JsonResponse{    public int $number;
    #[UseFaker("paragraph", 5, true)]    public string $message;}

Now when you execute your endpoint again, it will respond message with paragraph contains 5 sentences.

For complete formatter available, see Faker Documentation.

Create Custom Faker

You can also create your own faker generator by creating a class that implement Emsifa\Evo\Contracts\ValueFaker interface. Then, write your generator logic in generateFakeValue method. After that, you can just put its class name in UseFaker attribute before.

For example, we will create CategoryFaker that receive string $type, if $type is framework, it will return value either "Laravel", "Express.js", or "Next.js". Else, it will return either "Dessert", "Appetizer", or "Cocktail".

Create app/Fakers/CategoryFaker.php file with following code below:

<?php
namespace App\Fakers;
use Emsifa\Evo\Contracts\ValueFaker;use Faker\Generator;use ReflectionProperty;
class CategoryFaker implements ValueFaker{    public function __construct(protected string $type)    {    }
    public function generateFakeValue(Generator $faker, ReflectionProperty $property): mixed    {        if ($this->type == "framework") {            return $faker->randomElement(["Laravel", "Express.js", "Nest.js"]);        } else {            return $faker->randomElement(["Dessert", "Appetizer", "Cocktail"]);        }    }}

To use this, we can simply put "App\Fakers\CategoryFaker" in UseFaker attribute like following code below:

<?php
namespace App\Http\Responses;
use Emsifa\Evo\Dtos\UseFaker;use Emsifa\Evo\Http\Response\JsonResponse;use App\Fakers\CategoryFaker;
#[Description("Post something succeed")]class PostSomethingResponse extends JsonResponse{    public int $number;        #[UseFaker(CategoryFaker::class)]    public string $meal;
    #[UseFaker(CategoryFaker::class, "framework")]    public string $framework;}