server/server/api/media/[id]/index.ts

import { errorResponse } from "@response";
import { apiRoute, applyConfig } from "@api";

export const meta = applyConfig({
	allowedMethods: ["GET"],
	route: "/media/:id",
	ratelimits: {
		max: 100,
		duration: 60,
	},
	auth: {
		required: false,
	},
});

export default apiRoute(async (req, matchedRoute) => {
	// TODO: Add checks for disabled or not email verified accounts

	const id = matchedRoute.params.id;

	// parse `Range` header
	const [start = 0, end = Infinity] = (
		(req.headers.get("Range") || "")
			.split("=") // ["Range: bytes", "0-100"]
			.at(-1) || ""
	) // "0-100"
		.split("-") // ["0", "100"]
		.map(Number); // [0, 100]

	// Serve file from filesystem
	const file = Bun.file(`./uploads/${id}`);

	const buffer = await file.arrayBuffer();

	if (!(await file.exists())) return errorResponse("File not found", 404);

	// Can't directly copy file into Response because this crashes Bun for now
	return new Response(buffer, {
		headers: {
			"Content-Type": file.type || "application/octet-stream",
			"Content-Length": `${file.size - start}`,
			"Content-Range": `bytes ${start}-${end}/${file.size}`,
		},
	});
});