Extracted middleware and handlers

src/Http/Middleware/MercureHandler.php

@@ -0,0 +1,191 @@
+<?php
+
+namespace NoccyLabs\Mercureact\Http\Middleware;
+
+use NoccyLabs\Mercureact\Broker\Message;
+use NoccyLabs\Mercureact\Broker\TopicManager;
+use NoccyLabs\Mercureact\Configuration;
+use NoccyLabs\Mercureact\Http\Exeption\RequestException;
+use NoccyLabs\Mercureact\Http\Exeption\SecurityException;
+use NoccyLabs\SimpleJWT\JWTToken;
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use React\EventLoop\Loop;
+use React\EventLoop\LoopInterface;
+use React\Http\Message\Response;
+use React\Promise\Promise;
+use React\Promise\PromiseInterface;
+use React\Stream\ThroughStream;
+use SplObjectStorage;
+use Symfony\Component\Uid\Uuid;
+
+class MercureHandler
+{
+    private LoopInterface $loop;
+
+    public function __construct(
+        private Configuration $config,
+        private SplObjectStorage $eventClients,
+        private TopicManager $topicManager,
+        ?LoopInterface $loop=null
+    )
+    {
+        $this->loop = $loop ?? Loop::get();
+    }
+
+    /**
+     * Mecure handler middleware
+     * 
+     * @param ServerRequestInterface $request
+     * @param callable $next
+     * @return PromiseInterface
+     */
+    public function __invoke(ServerRequestInterface $request, callable $next): PromiseInterface
+    {
+        return new Promise(
+            function (callable $resolve, callable $reject) use ($next, $request) {
+                if ($request->getUri()->getPath() == "/.well-known/mercure") {
+                    if ($request->getMethod() == 'POST') {
+                        $resolve($this->handleMercurePublish($request));
+                        return;
+                    }
+                    $resolve($this->handleMercureClient($request));
+                } else {
+                    $resolve($next($request));
+                }
+            }
+        );
+    }
+
+    /**
+     * 
+     * 
+     * @param ServerRequestInterface $request
+     * @return ResponseInterface
+     */
+    private function handleMercureClient(ServerRequestInterface $request): ResponseInterface
+    {
+        $tok = $request->getAttribute('authorization');
+        if ($tok instanceof JWTToken) {
+            $claims = $tok->claims->getAll();
+            if (isset($claims['mercure']['subscribe'])) {
+                $subscribeClaims = $claims['mercure']['subscribe'];
+                // TODO check topic against subscribeClaims
+            }            
+        }
+
+        $responseStream = new ThroughStream();
+
+        $response = new Response(
+            body: $responseStream
+        );
+
+        $this->eventClients->attach($responseStream, $request);
+        $responseStream->on('close', function () use ($responseStream) {
+            $this->eventClients->detach($responseStream);;
+        });
+
+        return $response
+            ->withHeader("Cache-Control", "no-store")
+            ->withHeader("Content-Type", "text/event-stream");
+    }
+
+    /**
+     * 
+     * 
+     * @param ServerRequestInterface $request
+     * @return ResponseInterface
+     */
+    private function handleMercurePublish(ServerRequestInterface $request): ResponseInterface
+    {
+        if ($request->getHeaderLine('content-type') !== 'application/x-www-form-urlencoded') {
+            throw new \Exception("Invalid request");
+        }
+
+        // Parse out the urlencoded body. Pretty sure there is a better way to do this?
+        $body = explode("&", (string)$request->getBody());
+        $data = [];
+        foreach ($body as $param) {
+            if (!str_contains($param, "="))
+                throw new RequestException("Invalid request data", RequestException::ERR_INVALID_REQUEST_DATA);
+            [ $name, $value ] = array_map('urldecode', explode("=", $param, 2));
+            if (in_array($name, [ 'topic' ])) {
+                if (!isset($data[$name]))
+                    $data[$name] = [];
+                $data[$name][] = $value;
+            } else {
+                $data[$name] = $value;
+            }
+        }
+
+        // Grab the JWT token from the requests authorization attribute
+        $tok = $request->getAttribute('authorization');
+        if ($tok instanceof JWTToken) {
+            $claims = $tok->claims->getAll();
+            if (isset($claims['mercure']['publish'])) {
+                $publishClaims = $claims['mercure']['publish'];
+                // TODO check topic against publishClaims
+                if (!$this->checkTopicClaims($data['topic']??[], $publishClaims)) {
+                    throw new SecurityException("Insufficient permissions for publish", SecurityException::ERR_NO_PERMISSION);
+                }
+            }
+        } else {
+            // FIXME reject if access denied
+        }
+
+        // Put an id in there if none already
+        // TODO add a configurable for this
+        if (!isset($data['id'])) {
+            $data['id'] = (string)Uuid::v7();
+        }
+
+        // Attempt to create the message
+        $message = Message::fromData($data);
+
+        $this->loop->futureTick(function () use ($message) {
+            $this->publishMercureMessage($message);
+        });
+
+        return Response::plaintext("urn:uuid:".$message->id."\n");
+    }
+
+    private function checkTopicClaims(string|array $topic, array $claims): bool
+    {
+        foreach ((array)$topic as $match) {
+            foreach ($claims as $claim) {
+                if ($claim === "*") return true;
+                if ($claim === $match) return true;
+                // TODO implement full matching
+            }
+        }
+        return false;
+    }
+
+    /**
+     * 
+     * 
+     * @param Message $message
+     * @return void
+     */
+    private function publishMercureMessage(Message $message): void
+    {
+        // foreach ($this->webSocketClients as $webSocket) {
+        //     $webSocket->write(json_encode([
+        //         'type' => $message->type,
+        //         'topic' => $message->topic,
+        //         'data' => (@json_decode($message->data))??$message->data
+        //     ]));
+        // }
+
+        $sseMessage = "";
+        if ($message->type) {
+            $sseMessage .= "event: ".$message->type."\n";
+        }
+        $sseMessage .= "data: ".$message->data."\n\n";
+
+        foreach ($this->eventClients as $client) {
+            $client->write($sseMessage);
+        }
+    }
+
+}