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 type Logger from '@/logger.js'; import { FileInfoService } from '@/core/FileInfoService.js'; import { LoggerService } from '@/core/LoggerService.js'; @Injectable() export class MediaProxyServerService { private logger: Logger; constructor( @Inject(DI.config) private config: Config, private fileInfoService: FileInfoService, private downloadService: DownloadService, private imageProcessingService: ImageProcessingService, private loggerService: LoggerService, ) { this.logger = this.loggerService.getLogger('server', 'gray', false); } 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; } private 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) { this.logger.error(`${err}`); if (err instanceof StatusError && (err.statusCode === 302 || err.isClientError)) { ctx.status = err.statusCode; } else { ctx.status = 500; } } finally { cleanup(); } } }