server/api/media/[hash]/[name]/index.ts

import { apiRoute, handleZodError } from "@/api";
import { describeRoute } from "hono-openapi";
import { resolver, validator } from "hono-openapi/zod";
import { z } from "zod";
import { ApiError } from "~/classes/errors/api-error";

export default apiRoute((app) =>
    app.get(
        "/media/:hash/:name",
        describeRoute({
            summary: "Get media file by hash and name",
            responses: {
                200: {
                    description: "Media",
                    content: {
                        "*": {
                            schema: resolver(z.any()),
                        },
                    },
                },
                404: {
                    description: "File not found",
                    content: {
                        "application/json": {
                            schema: resolver(ApiError.zodSchema),
                        },
                    },
                },
            },
        }),
        validator(
            "param",
            z.object({
                hash: z.string(),
                name: z.string(),
            }),
            handleZodError,
        ),
        validator(
            "header",
            z.object({
                range: z.string().optional().default(""),
            }),
            handleZodError,
        ),
        async (context) => {
            const { hash, name } = context.req.valid("param");
            const { range } = context.req.valid("header");

            // parse `Range` header
            const [start = 0, end = Number.POSITIVE_INFINITY] = (
                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/${hash}/${name}`);

            const buffer = await file.arrayBuffer();

            if (!(await file.exists())) {
                throw new ApiError(404, "File not found");
            }

            // Can't directly copy file into Response because this crashes Bun for now
            return context.body(buffer, 200, {
                "Content-Type": file.type || "application/octet-stream",
                "Content-Length": `${file.size - start}`,
                "Content-Range": `bytes ${start}-${end}/${file.size}`,
                // biome-ignore lint/suspicious/noExplicitAny: Hono doesn't type this response so this has a TS error
            }) as any;
        },
    ),
);