jasny / http-digest

src/ServerMiddleware.php

<?php declare(strict_types=1);

namespace Jasny\HttpDigest;

use Psr\Http\Message\ServerRequestInterface as ServerRequest;
use Psr\Http\Message\ResponseInterface as Response;
use Psr\Http\Message\ResponseFactoryInterface as ResponseFactory;
use Psr\Http\Server\MiddlewareInterface;
use Psr\Http\Server\RequestHandlerInterface as RequestHandler;

/**
 * Middleware to verify HTTP Digest header.
 * Can be used both as single pass (PSR-15) and double pass middleware.
 */
class ServerMiddleware implements MiddlewareInterface
{
    /**
     * @var HttpDigest
     */
    protected $service;

    /**
     * @var ResponseFactory|null
     */
    protected $responseFactory;

    /**
     * @var bool
     */
    protected $optional = false;

    /**
     * Class constructor.
     *
     * @param HttpDigest        $service
     * @param ResponseFactory|null $responseFactory
     */
    public function __construct(HttpDigest $service, ?ResponseFactory $responseFactory = null)
    {
        $this->service = $service;
        $this->responseFactory = $responseFactory;
    }

    /**
     * Never require a Digest header, even for POST, etc requests.
     *
     * @param bool $optional
     * @return static
     */
    public function withOptionalDigest(bool $optional = true)
    {
        if ($this->optional === $optional) {
            return $this;
        }

        $clone = clone $this;
        $clone->optional = $optional;

        return $clone;
    }

    /**
     * Process an incoming server request (PSR-15).
     *
     * @param ServerRequest  $request
     * @param RequestHandler $handler
     * @return Response
     * @throws \RuntimeException if unauthorized response can't be created
     */
    public function process(ServerRequest $request, RequestHandler $handler): Response
    {
        $next = function (ServerRequest $request) use ($handler) {
            return $handler->handle($request);
        };

        return $request->hasHeader('Digest')
            ? $this->handleDigestRequest($request, null, $next)
            : $this->handleNoDigestRequest($request, null, $next);
    }

    /**
     * Get a callback that can be used as double pass middleware.
     *
     * @return callable
     */
    public function asDoublePass(): callable
    {
        return function (ServerRequest $request, Response $response, callable $next): Response {
            return $request->hasHeader('Digest')
                ? $this->handleDigestRequest($request, $response, $next)
                : $this->handleNoDigestRequest($request, $response, $next);
        };
    }


    /**
     * Check if the should have a digest header.
     *
     * @param ServerRequest $request
     * @return bool
     */
    protected function shouldHaveDigest(ServerRequest $request)
    {
        switch (strtoupper($request->getMethod())) {
            case 'GET':
            case 'HEAD':
            case 'OPTIONS':
                return false;

            case 'PATCH':
            case 'POST':
            case 'PUT':
                return true;

            default:
                return $request->getBody()->getSize() > 0;
        }
    }

    /**
     * Handle request with a Digest header.
     *
     * @param ServerRequest  $request
     * @param Response|null  $response
     * @param callable       $next
     * @return Response
     * @throws \RuntimeException when the bad request response can't be created.
     */
    protected function handleDigestRequest(ServerRequest $request, ?Response $response, callable $next): Response
    {
        try {
            $this->service->verify($request->getBody()->getContents(), $request->getHeaderLine('Digest'));
        } catch (HttpDigestException $exception) {
            return $this->createBadRequestResponse($response, $exception->getMessage());
        }

        return $next($request, $response);
    }

    /**
     * Handle request without a Digest header.
     *
     * @param ServerRequest  $request
     * @param Response|null  $response
     * @param callable       $next
     * @return Response
     * @throws \RuntimeException when the bad request response can't be created.
     */
    protected function handleNoDigestRequest(ServerRequest $request, ?Response $response, callable $next): Response
    {
        if (!$this->optional && $this->shouldHaveDigest($request)) {
            return $this->createBadRequestResponse($response, 'digest header missing');
        }

        return $next($request, $response);
    }

    /**
     * Create a response using the response factory.
     *
     * @param int           $status            Response status
     * @param Response|null $originalResponse
     * @return Response
     */
    protected function createResponse(int $status, ?Response $originalResponse = null): Response
    {
        if ($this->responseFactory === null && $originalResponse === null) {
            throw new \BadMethodCallException('Response factory not set');
        }

        return $this->responseFactory !== null

The expression return $this->responseFactory !== null ? $this->responseFactory->createResponse($status) : $originalResponse->withStatus($status)->withBody(clone $originalResponse->getBody()) could return the type null which is incompatible with the type-hinted return Psr\Http\Message\ResponseInterface. Consider adding an additional type-check to rule them out.

            ? $this->responseFactory->createResponse($status)
            : $originalResponse->withStatus($status)->withBody(clone $originalResponse->getBody());
    }

    /**
     * Create a `400 Bad Request` response.
     *
     * @param Response|null $response
     * @param string        $message
     * @return Response
     * @throws \RuntimeException when can't write body.
     */
    protected function createBadRequestResponse(?Response $response, string $message): Response
    {
        $errorResponse = $this->createResponse(400, $response)
            ->withHeader('Want-Digest', $this->service->getWantDigest())
            ->withHeader('Content-Type', 'text/plain');

        $errorResponse->getBody()->write($message);

        return $errorResponse;
    }
}