MiddlewarePipeline

Solo\Application\MiddlewarePipeline runs a list of PSR-15 middleware in front of a final request handler. It is a request handler itself. See Middleware for usage.

final class MiddlewarePipeline implements Psr\Http\Server\RequestHandlerInterface

Application::handle() creates one per request with the RouteDispatcher as the final handler, and RoutingMiddleware creates one for the route middleware.

__construct()

public function __construct(
    ContainerInterface $container,
    RequestHandlerInterface $finalHandler
)

$container resolves middleware given as IDs. $finalHandler handles the request once every middleware has passed it on.

add()

public function add(MiddlewareInterface|callable|string $middleware): self

Appends a middleware and returns the pipeline:

• a MiddlewareInterface instance;
• a callable with the signature of process(): fn(ServerRequestInterface $request, RequestHandlerInterface $handler): ResponseInterface;
• a container ID, such as a class name, that resolves to either.

Nothing is resolved or checked when a middleware is added.

addFromArray()

public function addFromArray(array $middlewares): self

Calls add() for each element, in order, and returns the pipeline.

handle()

public function handle(ServerRequestInterface $request): ResponseInterface

Passes the request to the first middleware, with a handler for the rest of the list; once the list is exhausted, calls the final handler. Each entry is resolved when the request reaches it:

• a string is a container ID, unless the container does not have it and PHP can call it, such as 'Class::staticMethod';
• anything else is used as it is.

The pipeline keeps no per-request state: it can handle any number of requests, and a middleware may call its $handler more than once.

Throws:

• InvalidArgumentException if an entry resolves to neither a MiddlewareInterface nor a callable;
• UnexpectedValueException if a callable middleware returns anything but a ResponseInterface;
• the container's NotFoundExceptionInterface for an ID it cannot resolve.

use Solo\Application\MiddlewarePipeline;

$response = (new MiddlewarePipeline($container, $finalHandler))
    ->add(JsonParserMiddleware::class)
    ->addFromArray([AuthMiddleware::class, new RateLimitMiddleware(60)])
    ->handle($request);