fully implement authenticated federated media (7f6be612) · Commits · sc07 / matrix-discord-bridge

src/lib/MultipartMixed.ts

0 → 100644

+49 −0

Original line number	Diff line number	Diff line
		import crypto from "node:crypto";
		import type Express from "express";

		type MultipartMixedPart = {
		headers: {
		[k: string]: string;
		};
		body: any;
		};

		export class MultipartMixed {
		readonly boundary = crypto.randomUUID();
		parts: MultipartMixedPart[] = [];

		add(part: MultipartMixedPart) {
		this.parts.push(part);
		return this;
		}

		send(res: Express.Response) {
		res.setHeader(
		"Content-Type",
		`multipart/mixed; boundary="${this.boundary}"`
		);
		res.send(this.toString());
		}

		toString() {
		const lines: string[] = [
		"sc07 matrix-discord-bridge multipart/mixed builder",
		];

		for (const part of this.parts) {
		lines.push("--" + this.boundary);

		for (const [header, value] of Object.entries(part.headers)) {
		lines.push(header + ": " + value);
		}

		lines.push("");
		lines.push(part.body);
		lines.push("");
		}

		lines.push("--" + this.boundary + "--");

		return lines.join("\r\n");
		}
		}

src/routes/media.ts

+61 −34

Original line number	Diff line number	Diff line
		@@ -6,15 +6,20 @@ import { Signed } from "../lib/signed";
		import { SignatureError } from "signed";
		import { Matrix } from "../lib/matrix";
		import { Router } from "./_router";
		import { MultipartMixed } from "../lib/MultipartMixed";

		export class MediaRoutes extends Router {
		override setup(router: e.Router) {
		router.get(
		"/_matrix/media/v3/download/:hostname/:name/:filename?",
		this.handleMedia.bind(this)
		this.handleLegacyMedia.bind(this)
		);
		router.get(
		"/_matrix/client/v1/media/download/:hostname/:name/:filename?",
		this.handleLegacyMedia.bind(this)
		);
		router.get(
		"/_matrix/federation/v1/media/download/:name",
		this.handleMedia.bind(this)
		);

		@@ -50,21 +55,12 @@ export class MediaRoutes extends Router {
		);
		}

		private async handleMedia(
		req: e.Request<{ hostname: string; name: string }>,
		res: e.Response
		) {
		if (req.params.hostname !== process.env.HOST) {
		res.status(400).json({
		errcode: "M_ERROR",
		error: "This service does not proxy external MXCs",
		});
		return;
		}

		const parts = Buffer.from(req.params.name, "base64url")
		.toString()
		.split(",");
		/**
		* Get target url from the media_id
		* @param media_id base64 encoded media_id
		*/
		private async parseURL(media_id: string): Promise<string \| null> {
		const parts = Buffer.from(media_id, "base64url").toString().split(",");

		const mode = parts.shift();
		let targetURL: string;
		@@ -79,10 +75,7 @@ export class MediaRoutes extends Router {
		message_id,
		attachment_id
		);
		if (!attachment) {
		res.status(404).json({});
		return;
		}
		if (!attachment) return null;

		targetURL = attachment;
		break;
		@@ -93,19 +86,13 @@ export class MediaRoutes extends Router {
		const user = await Discord.client.users
		.fetch(userid)
		.catch((e) => null);
		if (!user) {
		res.status(404).json({});
		return;
		}
		if (!user) return null;

		const avatarURL = user.avatarURL({
		extension: "png",
		forceStatic: true,
		});
		if (!avatarURL) {
		res.status(404).json({});
		return;
		}
		if (!avatarURL) return null;

		targetURL = avatarURL;
		break;
		@@ -116,10 +103,7 @@ export class MediaRoutes extends Router {
		const sticker = await Discord.client
		.fetchSticker(stickerid)
		.catch((e) => null);
		if (!sticker) {
		res.status(404).json({});
		return;
		}
		if (!sticker) return null;

		targetURL = sticker.url;
		break;
		@@ -133,7 +117,50 @@ export class MediaRoutes extends Router {
		break;
		}
		default:
		res.status(404).json({ errcode: "M_UNKNOWN", error: "Unknown media" });
		return null;
		}

		return targetURL;
		}

		private async handleMedia(req: e.Request<{ name: string }>, res: e.Response) {
		const targetURL = await this.parseURL(req.params.name);
		if (!targetURL) {
		res.status(404).json({});
		return;
		}

		new MultipartMixed()
		.add({
		headers: {
		"Content-Type": "application/json",
		},
		body: JSON.stringify({}),
		})
		.add({
		headers: {
		Location: targetURL,
		},
		body: "",
		})
		.send(res);
		}

		private async handleLegacyMedia(
		req: e.Request<{ hostname: string; name: string }>,
		res: e.Response
		) {
		if (req.params.hostname !== process.env.HOST) {
		res.status(400).json({
		errcode: "M_ERROR",
		error: "This service does not proxy external MXCs",
		});
		return;
		}

		const targetURL = await this.parseURL(req.params.name);
		if (!targetURL) {
		res.status(404).json({});
		return;
		}