1 files changed, 137 insertions, 0 deletions
diff --git a/packages/backend/src/server/MediaProxyServerService.ts b/packages/backend/src/server/MediaProxyServerService.ts
new file mode 100644
index 0000000000..b9cee38f0a
--- /dev/null
+++ b/packages/backend/src/server/MediaProxyServerService.ts
@@ -0,0 +1,137 @@
+import * as fs from 'node:fs';
+import { Inject, Injectable } from '@nestjs/common';
+import Koa from 'koa';
+import cors from '@koa/cors';
+import Router from '@koa/router';
+import sharp from 'sharp';
+import { DI } from '@/di-symbols.js';
+import { Config } from '@/config.js';
+import { isMimeImage } from '@/misc/is-mime-image.js';
+import { createTemp } from '@/misc/create-temp.js';
+import { DownloadService } from '@/core/DownloadService.js';
+import { ImageProcessingService } from '@/core/ImageProcessingService.js';
+import type { IImage } from '@/core/ImageProcessingService.js';
+import { FILE_TYPE_BROWSERSAFE } from '@/const.js';
+import { StatusError } from '@/misc/status-error.js';
+import Logger from '@/logger.js';
+import { FileInfoService } from '@/core/FileInfoService.js';
+
+const serverLogger = new Logger('server', 'gray', false);
+
+@Injectable()
+export class MediaProxyServerService {
+	constructor(
+		@Inject(DI.config)
+		private config: Config,
+
+		private fileInfoService: FileInfoService,
+		private downloadService: DownloadService,
+		private imageProcessingService: ImageProcessingService,
+	) {
+	}
+
+	public createServer() {
+		const app = new Koa();
+		app.use(cors());
+		app.use(async (ctx, next) => {
+			ctx.set('Content-Security-Policy', 'default-src \'none\'; img-src \'self\'; media-src \'self\'; style-src \'unsafe-inline\'');
+			await next();
+		});
+
+		// Init router
+		const router = new Router();
+
+		router.get('/:url*', ctx => this.#handler(ctx));
+
+		// Register router
+		app.use(router.routes());
+
+		return app;
+	}
+
+	async #handler(ctx: Koa.Context) {
+		const url = 'url' in ctx.query ? ctx.query.url : 'https://' + ctx.params.url;
+	
+		if (typeof url !== 'string') {
+			ctx.status = 400;
+			return;
+		}
+	
+		// Create temp file
+		const [path, cleanup] = await createTemp();
+	
+		try {
+			await this.downloadService.downloadUrl(url, path);
+	
+			const { mime, ext } = await this.fileInfoService.detectType(path);
+			const isConvertibleImage = isMimeImage(mime, 'sharp-convertible-image');
+	
+			let image: IImage;
+	
+			if ('static' in ctx.query && isConvertibleImage) {
+				image = await this.imageProcessingService.convertToWebp(path, 498, 280);
+			} else if ('preview' in ctx.query && isConvertibleImage) {
+				image = await this.imageProcessingService.convertToWebp(path, 200, 200);
+			} else if ('badge' in ctx.query) {
+				if (!isConvertibleImage) {
+					// 画像でないなら404でお茶を濁す
+					throw new StatusError('Unexpected mime', 404);
+				}
+	
+				const mask = sharp(path)
+					.resize(96, 96, {
+						fit: 'inside',
+						withoutEnlargement: false,
+					})
+					.greyscale()
+					.normalise()
+					.linear(1.75, -(128 * 1.75) + 128) // 1.75x contrast
+					.flatten({ background: '#000' })
+					.toColorspace('b-w');
+	
+				const stats = await mask.clone().stats();
+	
+				if (stats.entropy < 0.1) {
+					// エントロピーがあまりない場合は404にする
+					throw new StatusError('Skip to provide badge', 404);
+				}
+	
+				const data = sharp({
+					create: { width: 96, height: 96, channels: 4, background: { r: 0, g: 0, b: 0, alpha: 0 } },
+				})
+					.pipelineColorspace('b-w')
+					.boolean(await mask.png().toBuffer(), 'eor');
+	
+				image = {
+					data: await data.png().toBuffer(),
+					ext: 'png',
+					type: 'image/png',
+				};
+			}	else if (mime === 'image/svg+xml') {
+				image = await this.imageProcessingService.convertToWebp(path, 2048, 2048, 1);
+			} else if (!mime.startsWith('image/') || !FILE_TYPE_BROWSERSAFE.includes(mime)) {
+				throw new StatusError('Rejected type', 403, 'Rejected type');
+			} else {
+				image = {
+					data: fs.readFileSync(path),
+					ext,
+					type: mime,
+				};
+			}
+	
+			ctx.set('Content-Type', image.type);
+			ctx.set('Cache-Control', 'max-age=31536000, immutable');
+			ctx.body = image.data;
+		} catch (err) {
+			serverLogger.error(`${err}`);
+	
+			if (err instanceof StatusError && (err.statusCode === 302 || err.isClientError)) {
+				ctx.status = err.statusCode;
+			} else {
+				ctx.status = 500;
+			}
+		} finally {
+			cleanup();
+		}
+	}
+}