Merge pull request #1126 from DEVTomatoCake/feat/local-image-proxy

src/api/Server.ts

@@ -34,7 +34,7 @@ import "missing-native-js-functions";
 import morgan from "morgan";
 import path from "path";
 import { red } from "picocolors";
-import { Authentication, CORS } from "./middlewares/";
+import { Authentication, CORS, ImageProxy } from "./middlewares/";
 import { BodyParser } from "./middlewares/BodyParser";
 import { ErrorHandler } from "./middlewares/ErrorHandler";
 import { initRateLimits } from "./middlewares/RateLimit";
@@ -137,6 +137,8 @@ export class SpacebarServer extends Server {
 		app.use("/api/v9", api);
 		app.use("/api", api); // allow unversioned requests
 
+		app.use("/imageproxy/:hash/:size/:url", ImageProxy);
+
 		app.get("/", (req, res) =>
 			res.sendFile(path.join(PUBLIC_ASSETS_FOLDER, "index.html")),
 		);

src/api/middlewares/ImageProxy.ts

@@ -0,0 +1,180 @@
+/*
+        Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
+        Copyright (C) 2023 Spacebar and Spacebar Contributors
+
+        This program is free software: you can redistribute it and/or modify
+        it under the terms of the GNU Affero General Public License as published
+        by the Free Software Foundation, either version 3 of the License, or
+        (at your option) any later version.
+
+        This program is distributed in the hope that it will be useful,
+        but WITHOUT ANY WARRANTY; without even the implied warranty of
+        MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+        GNU Affero General Public License for more details.
+
+        You should have received a copy of the GNU Affero General Public License
+        along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+import { Config, JimpType } from "@spacebar/util";
+import { Request, Response } from "express";
+import { yellow } from "picocolors";
+import crypto from "crypto";
+import fetch from "node-fetch";
+
+let sharp: undefined | false | { default: typeof import("sharp") } = undefined;
+
+let Jimp: JimpType | undefined = undefined;
+try {
+	Jimp = require("jimp") as JimpType;
+} catch {
+	// empty
+}
+
+let sentImageProxyWarning = false;
+
+const sharpSupported = new Set([
+	"image/jpeg",
+	"image/png",
+	"image/bmp",
+	"image/tiff",
+	"image/gif",
+	"image/webp",
+	"image/avif",
+	"image/svg+xml",
+]);
+const jimpSupported = new Set([
+	"image/jpeg",
+	"image/png",
+	"image/bmp",
+	"image/tiff",
+	"image/gif",
+]);
+const resizeSupported = new Set([...sharpSupported, ...jimpSupported]);
+
+export async function ImageProxy(req: Request, res: Response) {
+	const path = req.originalUrl.split("/").slice(2);
+
+	// src/api/util/utility/EmbedHandlers.ts getProxyUrl
+	const hash = crypto
+		.createHmac("sha1", Config.get().security.requestSignature)
+		.update(path.slice(1).join("/"))
+		.digest("base64")
+		.replace(/\+/g, "-")
+		.replace(/\//g, "_");
+
+	try {
+		if (!crypto.timingSafeEqual(Buffer.from(hash), Buffer.from(path[0])))
+			throw new Error("Invalid signature");
+	} catch {
+		console.log("Invalid signature, expected " + hash + " got " + path[0]);
+		res.status(403).send("Invalid signature");
+		return;
+	}
+
+	const abort = new AbortController();
+	setTimeout(() => abort.abort(), 5000);
+
+	const request = await fetch(path.slice(2).join("/"), {
+		headers: {
+			"User-Agent": "SpacebarImageProxy/1.0.0 (https://spacebar.chat)",
+		},
+		signal: abort.signal,
+	}).catch((e) => {
+		if (e.name === "AbortError") res.status(504).send("Request timed out");
+		else res.status(500).send("Unable to proxy origin: " + e.message);
+	});
+	if (!request) return;
+
+	if (request.status !== 200) {
+		res.status(request.status).send(
+			"Origin failed to respond: " +
+				request.status +
+				" " +
+				request.statusText,
+		);
+		return;
+	}
+
+	if (
+		!request.headers.get("Content-Type") ||
+		!request.headers.get("Content-Length")
+	) {
+		res.status(500).send(
+			"Origin did not provide a Content-Type or Content-Length header",
+		);
+		return;
+	}
+
+	// @ts-expect-error TS doesn't believe that the header cannot be null (it's checked for falsiness above)
+	if (parseInt(request.headers.get("Content-Length")) > 1024 * 1024 * 10) {
+		res.status(500).send(
+			"Origin provided a Content-Length header that is too large",
+		);
+		return;
+	}
+
+	// @ts-expect-error TS doesn't believe that the header cannot be null (it's checked for falsiness above)
+	let contentType: string = request.headers.get("Content-Type");
+
+	const arrayBuffer = await request.arrayBuffer();
+	let resultBuffer = Buffer.from(arrayBuffer);
+
+	if (
+		!sentImageProxyWarning &&
+		resizeSupported.has(contentType) &&
+		/^\d+x\d+$/.test(path[1])
+	) {
+		if (sharp !== false) {
+			try {
+				sharp = await import("sharp");
+			} catch {
+				sharp = false;
+			}
+		}
+
+		if (sharp === false && !Jimp) {
+			try {
+				// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+				// @ts-ignore Typings don't fit
+				Jimp = await import("jimp");
+			} catch {
+				sentImageProxyWarning = true;
+				console.log(
+					`[ImageProxy] ${yellow(
+						'Neither "sharp" or "jimp" NPM packages are installed, image resizing will be disabled',
+					)}`,
+				);
+			}
+		}
+
+		const [width, height] = path[1].split("x").map((x) => parseInt(x));
+
+		const buffer = Buffer.from(arrayBuffer);
+		if (sharp && sharpSupported.has(contentType)) {
+			resultBuffer = await sharp
+				.default(buffer)
+				// Sharp doesn't support "scaleToFit"
+				.resize(width)
+				.toBuffer();
+		} else if (Jimp && jimpSupported.has(contentType)) {
+			resultBuffer = await Jimp.read(buffer).then((image) => {
+				contentType = image.getMIME();
+				return (
+					image
+						.scaleToFit(width, height)
+						// @ts-expect-error Jimp is defined at this point
+						.getBufferAsync(Jimp.AUTO)
+				);
+			});
+		}
+	}
+
+	res.header("Content-Type", contentType);
+	res.setHeader(
+		"Cache-Control",
+		"public, max-age=" + Config.get().cdn.proxyCacheHeaderSeconds,
+	);
+
+	res.send(resultBuffer);
+}

src/api/middlewares/index.ts

@@ -21,3 +21,4 @@ export * from "./BodyParser";
 export * from "./CORS";
 export * from "./ErrorHandler";
 export * from "./RateLimit";
+export * from "./ImageProxy";

src/util/config/types/CdnConfiguration.ts

@@ -1,17 +1,17 @@
 /*
 	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
 	Copyright (C) 2023 Spacebar and Spacebar Contributors
-	
+
 	This program is free software: you can redistribute it and/or modify
 	it under the terms of the GNU Affero General Public License as published
 	by the Free Software Foundation, either version 3 of the License, or
 	(at your option) any later version.
-	
+
 	This program is distributed in the hope that it will be useful,
 	but WITHOUT ANY WARRANTY; without even the implied warranty of
 	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 	GNU Affero General Public License for more details.
-	
+
 	You should have received a copy of the GNU Affero General Public License
 	along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
@@ -25,4 +25,6 @@ export class CdnConfiguration extends EndpointConfiguration {
 
 	endpointPublic: string | null = null;
 	endpointPrivate: string | null = null;
+
+	proxyCacheHeaderSeconds: number = 60 * 60 * 24;
 }

src/util/entities/UserSettings.ts

@@ -1,17 +1,17 @@
 /*
 	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
 	Copyright (C) 2023 Spacebar and Spacebar Contributors
-	
+
 	This program is free software: you can redistribute it and/or modify
 	it under the terms of the GNU Affero General Public License as published
 	by the Free Software Foundation, either version 3 of the License, or
 	(at your option) any later version.
-	
+
 	This program is distributed in the hope that it will be useful,
 	but WITHOUT ANY WARRANTY; without even the implied warranty of
 	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 	GNU Affero General Public License for more details.
-	
+
 	You should have received a copy of the GNU Affero General Public License
 	along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

src/util/imports/Jimp.ts

@@ -0,0 +1,23 @@
+/*
+	Spacebar: A FOSS re-implementation and extension of the Discord.com backend.
+	Copyright (C) 2023 Spacebar and Spacebar Contributors
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published
+	by the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/* eslint-disable @typescript-eslint/no-explicit-any */
+
+export type JimpType = {
+	read: (data: Buffer) => Promise<any>;
+};

src/util/imports/index.ts

@@ -18,3 +18,4 @@
 
 export * from "./OrmUtils";
 export * from "./Erlpack";
+export * from "./Jimp";