Middleware

Frigate has a powerful middleware system that allows you to execute code before and after a route is executed. Middleware can be used to modify the request, modify the response, or to execute additional logic before the route is executed. Middleware can be attached to a route or to a group of routes. Middleware can be used to implement authentication, logging, rate limiting, caching, and any other logic.

Each middleware is a class that implements the <? MiddlewareInterface interface OR a class that extends the <? BaseMiddleware class. Each middleware class should implement the <? exec method that takes:

• <? Methods $method - immutable the HTTP method of the route.
• <? RequestInterface $request - mutable the request object.
• <? ResponseInterface $response - mutable the response object.
• <? array $context - mutable the context of the route.
• <? Route $route - immutable the final route object.

The <? exec return a boolean value indicating wether execution should continue or not. It should modify the request, response, context to pass data between middleware modules and the target route.

Basic Middleware

Here is an example of a basic middleware that modifies the context of the route:

<?php

use Frigate\Middleware\BaseMiddleware;
use Frigate\Routing\Http\RequestInterface;
use Frigate\Routing\Http\ResponseInterface;
use Frigate\Routing\Routes\Route;

class MyMiddleware extends BaseMiddleware 
{
    public function exec(               // The only required method to implement
        Methods $method,                // The HTTP method of the route
        RequestInterface &$request,     // The request object which will be passed on. 
        ResponseInterface &$response,   // The response object which will be passed on.
        array &$context,                // The context of the route
        Route $target_route             // The final route object
    ) : bool {

        // Middleware logic goes here:
        $context['my_middleware'] = 'I am a middleware';

        // Return true to continue the execution of the route.
        // Return false to stop the execution of the route and return the response.
        return true; 
    }
}

After a middleware is executed, the context, request, and response objects are passed on to the next middleware or to the route handler. In case a middleware should stop the execution of the route, it can do so in two ways:

• By returning the <? False value which will stop the execution of the route and return the response.
• By throwing an <? Exception with the relevant error message and status code.

<?php

    // ... Middleware exec body

    // Example of a middleware that stops the execution of the route.
    $response->setStatus(401, "Unauthorized"); 
    return false;

    //Or:
    $response->setStatus(401); // Status message will be automatically set based on the status code.
    return false;

    //Or:
    throw new Exception("Unauthorized", 401);

    // ... Middleware exec body