rentgendroid/http_server/code/index.mjs

import express from "express";
import net from "net";
import fs from "fs";
import { readFile } from "node:fs/promises";

const device_size_x = 320;
const device_size_y = 640;

const app = express();
app.use(express.urlencoded({ extended: false }));
const socket_client = net.createConnection({ port: 3000, host: "android" });

async function sleep(time) {
  return new Promise((resolve) => setTimeout(resolve, time));
}

let doneWrite = 0;
let screenshotPromise = null;

async function screenshot() {
  const time_start = Date.now();
  socket_client.write("screenshot");
  while (!doneWrite) {
    await sleep(15);
    if (Date.now() - time_start > 2000) {
      console.error("Screenshot timed out after 2s");
      break; // timeout
    }
  }
  doneWrite = 0;
  screenshotPromise = null;
}

async function guardedScreenshot() {
  console.log("Requesting a screenshot");
  if (!screenshotPromise) {
    console.log("no ongoing promise, starting a new one");
    screenshotPromise = screenshot();
  }
  return screenshotPromise;
}

async function waitFullBoot() {
  var start = performance.now();
  var counter = 0;

  //will timeout after 10 min
  while (performance.now() - start < 600 * 1000) {
    var before = performance.now();
    await screenshot();
    var after = performance.now();
    if (after - before < process.env.screenshotDelayMs) counter++;
    else counter = 0;

    if (counter === 10) return;
  }

  throw new Error("wait for screenshot time to be less than 0.5s timed out");
}

let fd;
socket_client.on("data", (dataBuf) => {
  if (dataBuf.toString() === "start")
    fd = fs.openSync("/code/screenshot.png", "w");
  else {
    if (dataBuf.toString().includes("ENDOFMSG")) {
      fs.writeSync(fd, dataBuf);
      fs.close(fd);
      doneWrite = 1;
    } else fs.writeSync(fd, dataBuf);
  }
});

console.log("Waiting for full boot...");
await waitFullBoot();
console.log("Boot detected! activating endpoints");

app.get("/screen", async function (req, res) {
  await guardedScreenshot();
  res.sendFile("/code/screenshot.png");
});

app.get("/favicon.ico", function (req, res) {
  res.sendFile("/code/favicon.ico");
});

app.get("/trafficLog.js", function (req, res) {
  res.sendFile("/code/dist/trafficLog.js");
});

app.get("/trafficLog", async function (req, res) {
  res.sendFile("/log/trafficLog");
});

app.post("/touch", function (req, res) {
  const x = parseInt(req.body.x);
  const y = parseInt(req.body.y);

  if (isNaN(x) || isNaN(y) || x > device_size_x || y > device_size_y) {
    res.send(
      `the query params must be x <= ${device_size_x}, y <= ${device_size_y}\n`
    );
  } else {
    socket_client.write(`touch ${x} ${y}`);
    res.sendStatus(200);
  }
});

app.get("/", async function (req, res) {
  let fileData = (await readFile("/code/index.html")).toString();

  fileData = fileData.replace(
    "___screenshotDelayMs___",
    process.env.screenshotDelayMs
  );

  res.setHeader("Content-Type", "text/html");
  res.setHeader("Content-Disposition", "inline");

  res.send(fileData);
});

app.post("/back", function (req, res) {
  socket_client.write(`back`);
  res.sendStatus(200);
});

app.post("/home", function (req, res) {
  socket_client.write(`home`);
  res.sendStatus(200);
});

app.post("/drag", function (req, res) {
  const body = req.body;
  const startX = Number(body.startX);
  const startY = Number(body.startY);
  const endX = Number(body.endX);
  const endY = Number(body.endY);
  socket_client.write(`drag ${startX} ${startY} ${endX} ${endY}`);
  res.sendStatus(200);
});

app.listen(8080, () => console.log("Listening in port 8080"));