Simple library to abstract response data for several popular formats and provide output schema validation capabilities based on php-filter extension.

The use of ValidArray mechanism guarantees the output will match the predefined response schema.

Your controller is an HttpResponse object with predefined filters. Filters configuration corresponds to the response schema for the particular route and is defined in leaf data of routes file under response element.

During pre-rendering phase controller sets corresponding elements as defined in response. At this moment validation mechanism evaluates values and sanitizes them if necessary to correspond to the filtering rules.

Items not present in filters list are discarded. Invalid values are set to false. Correct values are set as is. Items present in validation schema but not set take null value. Rules may be modified using php-filter flags constants and ValidArray enhancements, including default values for all filters (not only FILTER_VALIDATE_* filters).

In the following example request controller UserGetEmail is defined in route file as a handler for GET /api/users/{id}/email route. On creation, it receives validation filters and an HttpRequest object with request information. When render() method is called on this controller, it renders an HTTP response as JSON text with corresponding headers, this work is done by JsonResponse. What is handled by the controller itself is located in preRender() method. It populates controller elements id (from request) and email (from User object). These pre-validated elements will correspond the initial response schema and will be output in a JSON format (like {"id":42,"email":"[email protected]"}).

<?php   // etc/api-routes.php

return [
    'GET /api/users/{id}/email' => [
        'controller' => App\Controller\UserGetEmail::class,
        'filters' => [
            'id' => ['filter' => FILTER_VALIDATE_INT, 'flags' => FILTER_REQUIRE_SCALAR],
        ],
        'response' => [
            'id' => FILTER_VALIDATE_INT,
            'email' => FILTER_VALIDATE_EMAIL,
        ],
    ]
];

<?php   // web/index.php

use Vertilia\Request\HttpRequest;
use Vertilia\Response\JsonResponse;
use Vertilia\Router\HttpRouter;

// initialize request object
$request = new HttpRequest(
    $_SERVER,
    $_GET,
    $_POST,
    $_COOKIE,
    $_FILES,
    file_get_contents('php://stdin')
);

// initialise HttpRouter with request and a list of routes
$router = new HttpRouter($request, ['../etc/api-routes.php']);

// get leaf structure from router, inject filters and parameters into $request
// elements to be present in leaf structure:
// - "container" to identify controller name
// - "filters" to validate request parameters filters
// - "response" filters for response structure
$leaf_structure = $router->getControllerFromRequest(App\NotFoundResponse::class);

// get HttpResponse object and render it
$response = new ($leaf_structure['controller'])($leaf_structure['response'] ?? [], $request);
$response->render();

<?php   // app/Controller/UserGetEmail.php

namespace App\Controller;

use Vertilia\Request\HttpRequest;
use Vertilia\Response\JsonResponse;

class UserGetEmail extends JsonResponse
{
    protected $request;

    public function __construct(array $filters, HttpRequest $request)
    {
        parent::__construct($filters);
        $this->request = $request;
    }

    public function preRender()
    {
        $this['id'] = $this->request['id'];
        $user = new App\Model\User($this['id']);
        $this['email'] = $user->getEmail();
    }
}

Since JsonResponse object is generated per operation, it includes exactly the filters needed for this specific operation. Populating and returning this response object guarantees that the rendered version will correspond to response schema.

Implementing preliminary check of required request parameters is what we leave to the user land since it is normally coupled with error messaging. If interested in implementing localised text messages, have a look at vertilia/text package on GitHub.

Correct instantiation and more use cases for HttpRequest and HttpRouter services may be found in corresponding packages, have a look at vertilia/request and vertilia/router pages.

A more complex controller implementation, handling request validation errors and multiple responses per route as defined in OpenAPI specification may be found in vertilia/controller package.