loled/loled.js

#!/bin/env -S deno run --allow-net --allow-env --allow-read=.
import { Application, Router } from "https://deno.land/x/oak/mod.ts";

let router = new Router()

let displayIndex = 0;
let display = null;

router.get("/_loled/display/register", (ctx) => {

  if(ctx.request.ip != "127.0.0.1"){
    ctx.response.status = 403
    ctx.response.body = "Only local machine is allowed to register a display"
    return;
  }

  let name = ctx.request.url.searchParams.get("name");
  if(!name){
    name = "display-"+displayIndex
  }
  displayIndex++;

  const target = ctx.sendEvents();
  display = { name, sse: target }
  target.dispatchMessage({ type: "welcome", name });
});

router.post("/_loled/grab-display",async (ctx) => {
  const bdy = await ctx.request.body({type: "json"}).value;

  if(display){
    display.sse.dispatchMessage({ type: "offer", offer: bdy.offer, iceCandidates: bdy.iceCandidates });

    const answr = await new Promise((res, rej) => {

      const timeout = setTimeout(() => {
        rej(new Error("Timeout"))
        delete display.putAnswer
      }, 10000)

      display.putAnswer = (answr) => {
        clearTimeout(timeout)
        delete display.putAnswer
        res(answr)
      }

    })

    ctx.response.type = "application/json"
    ctx.response.body = JSON.stringify(answr)

  } else {
    ctx.response.status = 404
    ctx.response.body = "No display available"
  }
})

router.post("/_loled/display/put-answer", async (ctx) => {
  const bdy = await ctx.request.body({type: "json"}).value;

  if(display){
    if(display.putAnswer){
      display.putAnswer(bdy)
      ctx.response.status = 200
    } else {
      ctx.response.status = 404
      ctx.response.body = "No offer pending"
    }
  } else {
    ctx.response.status = 404
    ctx.response.body = "No display available"
  }
});

const app = new Application();

// CORS
app.use((ctx, next) => {
  ctx.response.headers.append("Access-Control-Allow-Methods", "POST, GET, OPTIONS")
  ctx.response.headers.append("Access-Control-Allow-Origin", "*")
  ctx.response.headers.append("Access-Control-Max-Age", "3600")
  ctx.response.headers.append("Access-Control-Allow-Headers", "*")

  if(ctx.request.method == "OPTION"){
    ctx.response.status = 204
  } else {
    return next()
  }
})

app.use((ctx, next) => {
  if(ctx.request.url.pathname.startsWith("/_loled")){
  ctx.response.headers.append("Cache-Control", "no-store")
  }

  return next()
})

// Static
app.use(async (ctx, next) => {
  if(ctx.request.url.pathname.startsWith("/_loled"))
    return next()

  try {
    await ctx.send({
      root: `${Deno.cwd()}/static`,
      index: "index.html",
      path: ctx.request.url.pathname
    });
  } catch {
    ctx.response.status = 404
    ctx.response.body = "Not found"
  }
})

app.use(router.routes())
app.use(router.allowedMethods())

await app.listen({ port: Deno.env.get("PORT") || 80 });