<?php // FooClient.php

namespace App\Clients;

interface FooClient
{
    /**
     * Retrieve authorization token.
     *
     * @param array $credentials Just pass the login and password.
     * @return array             The json response.
     */
    public function login(array $credentials): array;

    /**
     * Retrieve all posts.
     *
     * @param string $authToken The authorization token.
     * @param array $query      Some optional query string Filters.
     * @return array            The list of posts.
     */
    public function getPosts(string $authToken, array $query = []): array:
}

<?php // FooClient.php

namespace App\Clients;

use Waffler\Waffler\Attributes\Auth\Bearer;
use Waffler\Waffler\Attributes\Request\Json;
use Waffler\Waffler\Attributes\Request\Post;
use Waffler\Waffler\Attributes\Request\Query;
use Waffler\Waffler\Attributes\Verbs\Get;

interface FooClient
{
    /**
     * Retrieve authorization token.
     *
     * @param array $credentials Just pass the login and password.
     * @return array             The json response.
     */
    #[Post('/auth/login')]
    public function login(#[Json] array $credentials): array;

    /**
     * Retrieve all posts.
     *
     * @param string $authToken The authorization token.
     * @param array $query      Some optional query string Filters.
     * @return array            The list of posts.
     */
    #[Get('/posts')]
    public function getPosts(#[Bearer] string $authToken, #[Query] array $query = []): array:
}

<?php

namespace App;

use App\Clients\FooClient;
use Waffler\Waffler\Client\Factory;

// Instantiate the client passing the interface as first argument.
$fooClient = Factory::make(FooClient::class, ['base_uri' => '<api-base-uri>']);

// Retrieve the credentials
$credentials = $this->fooClient->login([
    'email' => '[email protected]',
    'password' => '<secret>'
]);

// Retrieve the posts.
$posts = $this->fooClient->getPosts($credentials['token'], ['created_at' => '2020-01-01'])