bun-activitypub/src/index.ts

import { ACCOUNT, ACTOR, DEFAULT_DOCUMENTS, HOSTNAME, PORT, STATIC_PATH } from "./env";
import admin from './admin'
import activitypub from "./activitypub";
import { fetchObject } from "./request";
import path from "path"
import { BunFile } from "bun";
const { stat } = require("fs").promises

const server = Bun.serve({
  port: 3000,
  fetch(req: Request): Response | Promise<Response> {
    const url = new URL(req.url)

    console.log(`${new Date().toISOString()} ${req.method} ${req.url}`)

    if(req.method === "GET" && url.pathname === "/.well-known/webfinger") {
      return webfinger(req, url.searchParams.get("resource"))
    }
    else if(req.method === "GET" && url.pathname === "/fetch") {
      const object_url = url.searchParams.get('url')
      if(!object_url) return new Response("No url supplied", { status: 400})

      return fetchObject(ACTOR, object_url)
    }

    return admin(req) || activitypub(req) || staticFile(req)
  },
});

const webfinger = async (req: Request, resource: string | null) => {

  if(resource !== `acct:${ACCOUNT}@${HOSTNAME}`) return new Response("", { status: 404 })

  return Response.json({
    subject: `acct:${ACCOUNT}@${HOSTNAME}`,
    aliases: [ACTOR],
    links: [
      {
        "rel": "http://webfinger.net/rel/profile-page",
        "type": "text/html",
        "href": ACTOR
      },
      {
        rel: "self",
        type: "application/activity+json",
        href: ACTOR,
      },
    ],
  }, { headers: { "content-type": "application/activity+json" }})
}

const getDefaultDocument = async(base_path: string) => {
  for(const d of DEFAULT_DOCUMENTS){
    const filePath = path.join(base_path, d)
    const file = Bun.file(filePath)
    if(await file.exists()) return file
  }
}

const staticFile = async (req:Request): Promise<Response> => {
  try{
    const url = new URL(req.url)
    const filePath = path.join(STATIC_PATH, url.pathname)
    let file:BunFile|undefined = Bun.file(filePath)
    // if the file doesn't exist, attempt to get the default document for the path
    if(!(await file.exists())) file = await getDefaultDocument(filePath)
    
    if(file && await file.exists()) return new Response(file)
    // if the file still doesn't exist, just return a 404
    else return new Response("", { status: 404 })
  }
  catch(err) {
    console.error(err)
    return new Response("", { status: 404 })
  }
}
  
console.log(`Listening on http://localhost:${server.port} ...`);