feat(files_versions): Implement preview mime icon fallback

Signed-off-by: provokateurin <[email protected]>

apps/files_versions/lib/Controller/PreviewController.php

@@ -13,11 +13,13 @@
 use OCP\AppFramework\Http\Attribute\OpenAPI;
 use OCP\AppFramework\Http\DataResponse;
 use OCP\AppFramework\Http\FileDisplayResponse;
+use OCP\AppFramework\Http\RedirectResponse;
 use OCP\Files\IRootFolder;
 use OCP\Files\NotFoundException;
 use OCP\IPreview;
 use OCP\IRequest;
 use OCP\IUserSession;
+use OCP\Preview\IMimeIconProvider;
 
 #[OpenAPI(scope: OpenAPI::SCOPE_DEFAULT)]
 class PreviewController extends Controller {
@@ -29,6 +31,7 @@ public function __construct(
 		private IUserSession $userSession,
 		private IVersionManager $versionManager,
 		private IPreview $previewManager,
+		private IMimeIconProvider $mimeIconProvider,
 	) {
 		parent::__construct($appName, $request);
 	}
@@ -40,9 +43,11 @@ public function __construct(
 	 * @param int $x Width of the preview
 	 * @param int $y Height of the preview
 	 * @param string $version Version of the file to get the preview for
-	 * @return FileDisplayResponse<Http::STATUS_OK, array{Content-Type: string}>|DataResponse<Http::STATUS_BAD_REQUEST|Http::STATUS_NOT_FOUND, list<empty>, array{}>
+	 * @param bool $mimeFallback Whether to fallback to the mime icon if no preview is available
+	 * @return FileDisplayResponse<Http::STATUS_OK, array{Content-Type: string}>|DataResponse<Http::STATUS_BAD_REQUEST|Http::STATUS_NOT_FOUND, list<empty>, array{}>|RedirectResponse<Http::STATUS_SEE_OTHER, array{}>
 	 *
 	 * 200: Preview returned
+	 * 303: Redirect to the mime icon url if mimeFallback is true
 	 * 400: Getting preview is not possible
 	 * 404: Preview not found
 	 */
@@ -53,11 +58,13 @@ public function getPreview(
 		int $x = 44,
 		int $y = 44,
 		string $version = '',
+		bool $mimeFallback = false,
 	) {
 		if ($file === '' || $version === '' || $x === 0 || $y === 0) {
 			return new DataResponse([], Http::STATUS_BAD_REQUEST);
 		}
 
+		$versionFile = null;
 		try {
 			$user = $this->userSession->getUser();
 			$userFolder = $this->rootFolder->getUserFolder($user->getUID());
@@ -68,6 +75,14 @@ public function getPreview(
 			$response->cacheFor(3600 * 24, false, true);
 			return $response;
 		} catch (NotFoundException $e) {
+			// If we have no preview enabled, we can redirect to the mime icon if any
+			if ($mimeFallback && $versionFile !== null) {
+				$url = $this->mimeIconProvider->getMimeIconUrl($versionFile->getMimeType());
+				if ($url !== null) {
+					return new RedirectResponse($url);
+				}
+			}
+
 			return new DataResponse([], Http::STATUS_NOT_FOUND);
 		} catch (\InvalidArgumentException $e) {
 			return new DataResponse([], Http::STATUS_BAD_REQUEST);

apps/files_versions/openapi.json

@@ -103,6 +103,19 @@
                             "type": "string",
                             "default": ""
                         }
+                    },
+                    {
+                        "name": "mimeFallback",
+                        "in": "query",
+                        "description": "Whether to fallback to the mime icon if no preview is available",
+                        "schema": {
+                            "type": "integer",
+                            "default": 0,
+                            "enum": [
+                                0,
+                                1
+                            ]
+                        }
                     }
                 ],
                 "responses": {
@@ -132,6 +145,16 @@
                                 "schema": {}
                             }
                         }
+                    },
+                    "303": {
+                        "description": "Redirect to the mime icon url if mimeFallback is true",
+                        "headers": {
+                            "Location": {
+                                "schema": {
+                                    "type": "string"
+                                }
+                            }
+                        }
                     }
                 }
             }