Refactor FileServerService: Extract file handling logic into dedicated handlers (#17090)

- Introduced FileServerDriveHandler to manage drive file requests.
- Created FileServerFileResolver for resolving file access keys and downloading files.
- Added FileServerProxyHandler to handle proxy requests and image processing.
- Moved utility functions to FileServerUtils for better organization.
- Removed redundant methods from FileServerService, improving readability and maintainability.

1 files changed, 116 insertions, 0 deletions

diff --git a/packages/backend/src/server/file/FileServerDriveHandler.ts b/packages/backend/src/server/file/FileServerDriveHandler.ts
new file mode 100644
index 0000000000..51b527b146
--- /dev/null
+++ b/packages/backend/src/server/file/FileServerDriveHandler.ts
@@ -0,0 +1,116 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import * as fs from 'node:fs';
+import rename from 'rename';
+import type { Config } from '@/config.js';
+import type { IImageStreamable } from '@/core/ImageProcessingService.js';
+import { contentDisposition } from '@/misc/content-disposition.js';
+import { correctFilename } from '@/misc/correct-filename.js';
+import { isMimeImage } from '@/misc/is-mime-image.js';
+import { VideoProcessingService } from '@/core/VideoProcessingService.js';
+import { attachStreamCleanup, handleRangeRequest, setFileResponseHeaders, getSafeContentType, needsCleanup } from './FileServerUtils.js';
+import type { FileServerFileResolver } from './FileServerFileResolver.js';
+import type { FastifyReply, FastifyRequest } from 'fastify';
+
+export class FileServerDriveHandler {
+	constructor(
+		private config: Config,
+		private fileResolver: FileServerFileResolver,
+		private assetsPath: string,
+		private videoProcessingService: VideoProcessingService,
+	) {}
+
+	public async handle(request: FastifyRequest<{ Params: { key: string } }>, reply: FastifyReply) {
+		const key = request.params.key;
+		const file = await this.fileResolver.resolveFileByAccessKey(key);
+
+		if (file.kind === 'not-found') {
+			reply.code(404);
+			reply.header('Cache-Control', 'max-age=86400');
+			return reply.sendFile('/dummy.png', this.assetsPath);
+		}
+
+		if (file.kind === 'unavailable') {
+			reply.code(204);
+			reply.header('Cache-Control', 'max-age=86400');
+			return;
+		}
+
+		try {
+			if (file.kind === 'remote') {
+				let image: IImageStreamable | null = null;
+
+				if (file.fileRole === 'thumbnail') {
+					if (isMimeImage(file.mime, 'sharp-convertible-image-with-bmp')) {
+						reply.header('Cache-Control', 'max-age=31536000, immutable');
+
+						const url = new URL(`${this.config.mediaProxy}/static.webp`);
+						url.searchParams.set('url', file.url);
+						url.searchParams.set('static', '1');
+
+						file.cleanup();
+						return await reply.redirect(url.toString(), 301);
+					} else if (file.mime.startsWith('video/')) {
+						const externalThumbnail = this.videoProcessingService.getExternalVideoThumbnailUrl(file.url);
+						if (externalThumbnail) {
+							file.cleanup();
+							return await reply.redirect(externalThumbnail, 301);
+						}
+
+						image = await this.videoProcessingService.generateVideoThumbnail(file.path);
+					}
+				}
+
+				if (file.fileRole === 'webpublic') {
+					if (['image/svg+xml'].includes(file.mime)) {
+						reply.header('Cache-Control', 'max-age=31536000, immutable');
+
+						const url = new URL(`${this.config.mediaProxy}/svg.webp`);
+						url.searchParams.set('url', file.url);
+
+						file.cleanup();
+						return await reply.redirect(url.toString(), 301);
+					}
+				}
+
+				image ??= {
+					data: handleRangeRequest(reply, request.headers.range as string | undefined, file.file.size, file.path),
+					ext: file.ext,
+					type: file.mime,
+				};
+
+				attachStreamCleanup(image.data, file.cleanup);
+
+				reply.header('Content-Type', getSafeContentType(image.type));
+				reply.header('Content-Length', file.file.size);
+				reply.header('Cache-Control', 'max-age=31536000, immutable');
+				reply.header('Content-Disposition',
+					contentDisposition(
+						'inline',
+						correctFilename(file.filename, image.ext),
+					),
+				);
+				return image.data;
+			}
+
+			if (file.fileRole !== 'original') {
+				const filename = rename(file.filename, {
+					suffix: file.fileRole === 'thumbnail' ? '-thumb' : '-web',
+					extname: file.ext ? `.${file.ext}` : '.unknown',
+				}).toString();
+
+				setFileResponseHeaders(reply, { mime: file.mime, filename });
+				return handleRangeRequest(reply, request.headers.range as string | undefined, file.file.size, file.path);
+			} else {
+				setFileResponseHeaders(reply, { mime: file.file.type, filename: file.filename, size: file.file.size });
+				return handleRangeRequest(reply, request.headers.range as string | undefined, file.file.size, file.path);
+			}
+		} catch (e) {
+			if (file.kind === 'remote') file.cleanup();
+			throw e;
+		}
+	}
+}