feat: add JsonBodyParser middleware

src/Middleware/JsonBodyParser.php

@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Horde\Http\Server\Middleware;
+
+use Psr\Http\Message\ResponseInterface;
+use Psr\Http\Message\ServerRequestInterface;
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+
+/**
+ * JSON Body Parser Middleware
+ *
+ * Parses JSON request bodies and makes them available via getParsedBody().
+ * This solves the php://input non-seekable stream issue by reading the body
+ * once and caching the parsed result in the request.
+ *
+ * Usage in route configuration:
+ * ```php
+ * $mapper->connect('api_endpoint', '/api/endpoint', [
+ *     'controller' => MyApiController::class,
+ *     'stack' => [JsonBodyParser::class],
+ * ]);
+ * ```
+ *
+ * In controllers, use getParsedBody() instead of reading getBody():
+ * ```php
+ * public function handle(ServerRequestInterface $request): ResponseInterface
+ * {
+ *     $body = $request->getParsedBody(); // array|null
+ *     $username = $body['username'] ?? null;
+ * }
+ * ```
+ *
+ * Copyright 2026 The Horde Project (http://www.horde.org/)
+ *
+ * See the enclosed file LICENSE for license information (LGPL). If you
+ * did not receive this file, see http://www.horde.org/licenses/lgpl21.
+ *
+ * @category Horde
+ * @package  Http_Server
+ * @license  http://www.horde.org/licenses/lgpl21 LGPL 2.1
+ */
+class JsonBodyParser implements MiddlewareInterface
+{
+    /**
+     * Process the request and parse JSON body if present
+     *
+     * @param ServerRequestInterface $request
+     * @param RequestHandlerInterface $handler
+     * @return ResponseInterface
+     */
+    public function process(
+        ServerRequestInterface $request,
+        RequestHandlerInterface $handler
+    ): ResponseInterface {
+        // Only parse if Content-Type indicates JSON
+        $contentType = $request->getHeaderLine('Content-Type');
+
+        if (str_contains($contentType, 'application/json')) {
+            // Read body stream once - php://input is non-seekable
+            $body = (string) $request->getBody();
+
+            if ($body !== '') {
+                $parsed = json_decode($body, true);
+
+                // Only set parsedBody if JSON is valid
+                if (json_last_error() === JSON_ERROR_NONE && is_array($parsed)) {
+                    $request = $request->withParsedBody($parsed);
+                }
+            }
+        }
+
+        return $handler->handle($request);
+    }
+}