期限切れ/未保存リモートファイルのローカルプロキシ (#5655)

* Media Proxy を実装

* サンプルを追加

* https://github.com/syuilo/misskey/pull/5649#discussion_r359967471 の修正

* https://github.com/syuilo/misskey/pull/5649#discussion_r359967966 の修正

* https://github.com/syuilo/misskey/pull/5649#discussion_r359968219 の修正

* 期限切れ/未保存リモートファイルのローカルプロキシ

* 設定

* 説明

* comment out

* fix

Co-authored-by: 和風ドレッシング <37681609+CookieRamen@users.noreply.github.com>

3 files changed, 76 insertions, 3 deletions

diff --git a/src/server/api/endpoints/admin/update-meta.ts b/src/server/api/endpoints/admin/update-meta.ts
index 05a1e25c01..bc37228d0a 100644
--- a/src/server/api/endpoints/admin/update-meta.ts
+++ b/src/server/api/endpoints/admin/update-meta.ts
@@ -151,6 +151,13 @@ export const meta = {
 			}
 		},
 
+		proxyRemoteFiles: {
+			validator: $.optional.bool,
+			desc: {
+				'ja-JP': 'ローカルにないリモートのファイルをプロキシするか否か'
+			}
+		},
+
 		enableRecaptcha: {
 			validator: $.optional.bool,
 			desc: {
@@ -478,6 +485,10 @@ export default define(meta, async (ps, me) => {
 		set.cacheRemoteFiles = ps.cacheRemoteFiles;
 	}
 
+	if (ps.proxyRemoteFiles !== undefined) {
+		set.proxyRemoteFiles = ps.proxyRemoteFiles;
+	}
+
 	if (ps.enableRecaptcha !== undefined) {
 		set.enableRecaptcha = ps.enableRecaptcha;
 	}
diff --git a/src/server/api/endpoints/meta.ts b/src/server/api/endpoints/meta.ts
index 6df6362a6f..b71c35946e 100644
--- a/src/server/api/endpoints/meta.ts
+++ b/src/server/api/endpoints/meta.ts
@@ -143,6 +143,7 @@ export default define(meta, async (ps, me) => {
 		driveCapacityPerLocalUserMb: instance.localDriveCapacityMb,
 		driveCapacityPerRemoteUserMb: instance.remoteDriveCapacityMb,
 		cacheRemoteFiles: instance.cacheRemoteFiles,
+		proxyRemoteFiles: instance.proxyRemoteFiles,
 		enableRecaptcha: instance.enableRecaptcha,
 		recaptchaSiteKey: instance.recaptchaSiteKey,
 		swPublickey: instance.swPublicKey,
diff --git a/src/server/file/send-drive-file.ts b/src/server/file/send-drive-file.ts
index a05477488b..e0aea5b42f 100644
--- a/src/server/file/send-drive-file.ts
+++ b/src/server/file/send-drive-file.ts
@@ -1,10 +1,16 @@
 import * as Koa from 'koa';
 import * as send from 'koa-send';
 import * as rename from 'rename';
+import * as tmp from 'tmp';
+import * as fs from 'fs';
 import { serverLogger } from '..';
 import { contentDisposition } from '../../misc/content-disposition';
 import { DriveFiles } from '../../models';
 import { InternalStorage } from '../../services/drive/internal-storage';
+import { downloadUrl } from '../../misc/donwload-url';
+import { detectMine } from '../../misc/detect-mine';
+import { convertToJpeg, convertToPng, convertToGif, convertToApng } from '../../services/drive/image-processor';
+import { GenerateVideoThumbnail } from '../../services/drive/generate-video-thumbnail';
 
 const assets = `${__dirname}/../../server/file/assets/`;
 
@@ -31,15 +37,70 @@ export default async function(ctx: Koa.Context) {
 		return;
 	}
 
+	const isThumbnail = file.thumbnailAccessKey === key;
+	const isWebpublic = file.webpublicAccessKey === key;
+
 	if (!file.storedInternal) {
+		if (file.isLink && file.uri) {	// 期限切れリモートファイル
+			const [path, cleanup] = await new Promise<[string, any]>((res, rej) => {
+				tmp.file((e, path, fd, cleanup) => {
+					if (e) return rej(e);
+					res([path, cleanup]);
+				});
+			});
+
+			try {
+				await downloadUrl(file.uri, path);
+
+				const [type, ext] = await detectMine(path);
+
+				const convertFile = async () => {
+					if (isThumbnail) {
+						if (['image/jpeg', 'image/webp'].includes(type)) {
+							return await convertToJpeg(path, 498, 280);
+						} else if (['image/png'].includes(type)) {
+							return await convertToPng(path, 498, 280);
+						} else if (['image/gif'].includes(type)) {
+							return await convertToGif(path);
+						} else if (['image/apng', 'image/vnd.mozilla.apng'].includes(type)) {
+							return await convertToApng(path);
+						} else if (type.startsWith('video/')) {
+							return await GenerateVideoThumbnail(path);
+						}
+					}
+
+					return {
+						data: fs.readFileSync(path),
+						ext,
+						type,
+					};
+				};
+
+				const image = await convertFile();
+				ctx.body = image.data;
+				ctx.set('Content-Type', file.type);
+				ctx.set('Cache-Control', 'max-age=31536000, immutable');
+			} catch (e) {
+				serverLogger.error(e);
+
+				if (typeof e == 'number' && e >= 400 && e < 500) {
+					ctx.status = e;
+					ctx.set('Cache-Control', 'max-age=86400');
+				} else {
+					ctx.status = 500;
+					ctx.set('Cache-Control', 'max-age=300');
+				}
+			} finally {
+				cleanup();
+			}
+			return;
+		}
+
 		ctx.status = 204;
 		ctx.set('Cache-Control', 'max-age=86400');
 		return;
 	}
 
-	const isThumbnail = file.thumbnailAccessKey === key;
-	const isWebpublic = file.webpublicAccessKey === key;
-
 	if (isThumbnail) {
 		ctx.body = InternalStorage.read(key);
 		ctx.set('Content-Type', 'image/jpeg');