Middleware is used to perform additional checks in routers. Middleware implements the MiddlewareInterface. It uses two methods for this validation, one is to perform the check, and the other one is used for formulating the correct response. An example middleware which does a check for a header would be:
<?php
namespace MyProject\MyPackage\Component\Middleware;
use Ulrack\Web\Common\Endpoint\InputInterface;
use Ulrack\Web\Common\Endpoint\OutputInterface;
use Ulrack\Web\Common\Middleware\MiddlewareInterface;
class HeaderCheckingMiddleware implements MiddlewareInterface
{
/**
* Retrieves the error code for the middleware if it does not pass.
*
* @return int
*/
public function getErrorCode(): int
{
return 401;
}
/**
* Performs additional checks on the route.
*
* @param InputInterface $input
* @param OutputInterface $output
*
* @return bool
*/
public function pass(
InputInterface $input,
OutputInterface $output
): bool {
$request = $input->getRequest();
if (
$request->hasHeader('Authorization') &&
$request->getHeader('Authorization') === 'my-auth-code'
) {
return true;
}
return false;
}
}This middleware could then be used in a MiddlewareRouter to perform the check when a request is made to another router.
The following implementations for middleware are provided in this package:
- HostMatchingMiddleware for matching the host of a request to one or multiple patterns.
- MethodMatchingMiddleware for checking the method of a request.
- PathMatchingMiddleware
for checking a path to a pattern/route. It supports wildcards with names e.g.
users/{userId}. When the path matches, theuserIdis stored in the input. - PortMatchingMiddleware for checking the port of a request.
- MiddlewareAggregate for chaining multiple middlewares together to put in one MiddlewareRouter.