add legacy route director that should fix all forum links, fixes #5698

Closes #5698

Merge request studip/studip!4326

1 files changed, 105 insertions, 0 deletions

diff --git a/lib/middleware/LegacyRedirectorMiddleware.php b/lib/middleware/LegacyRedirectorMiddleware.php
new file mode 100644
index 0000000..5b9960c
--- /dev/null
+++ b/lib/middleware/LegacyRedirectorMiddleware.php
@@ -0,0 +1,105 @@
+<?php
+namespace Studip\Middleware;
+
+use Forum\ForumTopic;
+use NotificationCenter;
+use Psr\Http\Message\ResponseFactoryInterface;
+use Psr\Http\Message\{ResponseInterface as Response,
+    ServerRequestInterface as Request,
+    UriInterface
+};
+use Psr\Http\Server\MiddlewareInterface;
+use Psr\Http\Server\RequestHandlerInterface;
+use Slim\App;
+
+final class LegacyRedirectorMiddleware implements MiddlewareInterface
+{
+    private array $legacyRoutes = [];
+
+    public function __construct(
+        private readonly App $app,
+        private readonly ResponseFactoryInterface $response_factory
+    ) {
+        $this->addLegacyRoute(
+            '#^course/forum/index/index#',
+            [$this, 'redirectForumPost']
+        );
+
+        NotificationCenter::postNotification('LEGACY_REDIRECTOR_DID_CREATE', $this);
+    }
+
+    public function addLegacyRoute(string $route, callable $handler): void
+    {
+        $this->legacyRoutes[$route] = $handler;
+    }
+
+    public function process(Request $request, RequestHandlerInterface $handler): Response
+    {
+        $path = $this->getRelativePath($request);
+
+        foreach ($this->legacyRoutes as $legacyRoute => $routeHandler) {
+            if ($this->routeMatches($path, $legacyRoute)) {
+                /** @var UriInterface $newUri */
+                $newUri = $routeHandler($request);
+
+                $response = $this->response_factory->createResponse(301);
+                $response->getBody()->write('');
+                return $response->withHeader('Location', (string) $newUri);
+            }
+        }
+
+        return $handler->handle($request);
+    }
+
+    private function getRelativePath(Request $request): string
+    {
+        $basePath = $this->app->getBasePath();
+        $fullPath = $request->getUri()->getPath();
+
+        return ltrim(substr($fullPath, strlen($basePath)), '/');
+    }
+
+    private function routeMatches(string $path, string $route): bool
+    {
+        if (str_starts_with($route, '#') && str_ends_with($route, '#')) {
+            return preg_match($route, $path);
+        }
+
+        return str_starts_with($path, $route);
+    }
+
+    private function redirectForumPost(Request $request): UriInterface
+    {
+        $uri = $request->getUri();
+        $range_id = $request->getQueryParams()['cid'];
+        $forum_id = explode('/', $this->getRelativePath($request))[4] ?? null;
+
+        if ($forum_id === $range_id) {
+            $redirectUri = $uri->withPath(
+                str_replace(
+                    'course/forum/index/index/' . $forum_id,
+                    'course/forum/topics',
+                    $uri->getPath()
+                )
+            );
+        } elseif (ForumTopic::exists($forum_id)) {
+            $redirectUri = $uri->withPath(
+                str_replace(
+                    'course/forum/index/index',
+                    'course/forum/topics/show',
+                    $uri->getPath()
+                )
+            );
+        } else {
+            $redirectUri = $uri->withPath(
+                str_replace(
+                    'course/forum/index/index',
+                    'course/forum/discussions/show',
+                    $uri->getPath()
+                )
+            );
+        }
+
+        return $redirectUri;
+    }
+}