(fix) `/files` をバイトレンジリクエストに対応させる

packages/backend/src/server/FileServerService.ts

@@ -168,6 +168,29 @@ export class FileServerService {
 				}
 
 				if (!image) {
+					if (request.headers.range) {
+						const range = request.headers.range as string;
+						const parts = range.replace(/bytes=/, '').split('-');
+						const start = parseInt(parts[0], 10);
+						let end = parts[1] ? parseInt(parts[1], 10) : file.file.size - 1;
+						if (end > file.file.size) {
+							end = file.file.size - 1;
+						}
+
+						image = {
+							data: fs.createReadStream(file.path, {
+								start,
+								end,
+							}),
+							ext: file.ext,
+							type: file.mime,
+						};
+
+						const chunksize = end - start + 1;
+						reply.header('Content-Range', `bytes ${start}-${end}/${file.file.size}`);
+						reply.header('Accept-Ranges', 'bytes');
+						reply.header('Content-Length', chunksize);
+					}
 					image = {
 						data: fs.createReadStream(file.path),
 						ext: file.ext,
@@ -203,11 +226,54 @@ export class FileServerService {
 				reply.header('Content-Type', FILE_TYPE_BROWSERSAFE.includes(file.mime) ? file.mime : 'application/octet-stream');
 				reply.header('Cache-Control', 'max-age=31536000, immutable');
 				reply.header('Content-Disposition', contentDisposition('inline', filename));
+
+				if (request.headers.range) {
+					const range = request.headers.range as string;
+					const parts = range.replace(/bytes=/, '').split('-');
+					const start = parseInt(parts[0], 10);
+					let end = parts[1] ? parseInt(parts[1], 10) : file.file.size - 1;
+					if (end > file.file.size) {
+						end = file.file.size - 1;
+					}
+					const chunksize = end - start + 1;
+					const fileStream = fs.createReadStream(file.path, {
+						start,
+						end,
+					});
+					reply.header('Content-Range', `bytes ${start}-${end}/${file.file.size}`);
+					reply.header('Accept-Ranges', 'bytes');
+					reply.header('Content-Length', chunksize);
+					reply.code(206);
+					return fileStream;
+				}
+
 				return fs.createReadStream(file.path);
 			} else {
 				reply.header('Content-Type', FILE_TYPE_BROWSERSAFE.includes(file.file.type) ? file.file.type : 'application/octet-stream');
 				reply.header('Cache-Control', 'max-age=31536000, immutable');
 				reply.header('Content-Disposition', contentDisposition('inline', file.filename));
+
+				if (request.headers.range) {
+					const range = request.headers.range as string;
+					const parts = range.replace(/bytes=/, '').split('-');
+					const start = parseInt(parts[0], 10);
+					let end = parts[1] ? parseInt(parts[1], 10) : file.file.size - 1;
+					console.log(end);
+					if (end > file.file.size) {
+						end = file.file.size - 1;
+					}
+					const chunksize = end - start + 1;
+					const fileStream = fs.createReadStream(file.path, {
+						start,
+						end,
+					});
+					reply.header('Content-Range', `bytes ${start}-${end}/${file.file.size}`);
+					reply.header('Accept-Ranges', 'bytes');
+					reply.header('Content-Length', chunksize);
+					reply.code(206);
+					return fileStream;
+				}
+
 				return fs.createReadStream(file.path);
 			}
 		} catch (e) {