codex-app-server/cloud/codex-ui-host/host/cdp-load.mjs

#!/usr/bin/env node
/**
 * Load the local web host in the headless browser, capture console + exceptions,
 * then dump the resulting page state and a screenshot.
 *
 *   node host/cdp-load.mjs --port 9333 --url http://127.0.0.1:8095/ --out /tmp/shot.png
 */

import fs from "node:fs";

const argv = process.argv.slice(2);
const argOf = (name, fallback) => {
  const i = argv.indexOf(name);
  return i !== -1 && argv[i + 1] ? argv[i + 1] : fallback;
};
const PORT = argOf("--port", "9333");
const URL_ = argOf("--url", "http://127.0.0.1:8095/");
const OUT = argOf("--out", "/tmp/codexweb.png");
const SETTLE = Number(argOf("--settle", "6000"));

const version = await (await fetch(`http://127.0.0.1:${PORT}/json/version`)).json();
const ws = new WebSocket(version.webSocketDebuggerUrl);
let seq = 0;
const pending = new Map();
const events = [];

const send = (method, params = {}, sessionId) =>
  new Promise((resolve, reject) => {
    const id = ++seq;
    pending.set(id, { resolve, reject });
    const msg = { id, method, params };
    if (sessionId) msg.sessionId = sessionId;
    ws.send(JSON.stringify(msg));
  });

ws.addEventListener("message", (ev) => {
  const msg = JSON.parse(ev.data);
  if (msg.method) {
    if (msg.method === "Runtime.consoleAPICalled") {
      const text = (msg.params.args || [])
        .map((a) => a.value ?? a.description ?? a.unserializableValue ?? "")
        .join(" ")
        .slice(0, 600);
      events.push(`[${msg.params.type}] ${text}`);
    } else if (msg.method === "Runtime.exceptionThrown") {
      const d = msg.params.exceptionDetails;
      events.push(`[EXCEPTION] ${d.exception?.description ?? d.text}`.slice(0, 2200));
    } else if (msg.method === "Log.entryAdded") {
      const e = msg.params.entry;
      events.push(`[log:${e.level}] ${e.text}`.slice(0, 500));
    }
  }
  if (!msg.id || !pending.has(msg.id)) return;
  const { resolve, reject } = pending.get(msg.id);
  pending.delete(msg.id);
  msg.error ? reject(new Error(JSON.stringify(msg.error).slice(0, 400))) : resolve(msg.result);
});

await new Promise((r) => ws.addEventListener("open", r, { once: true }));

const { targetInfos } = await send("Target.getTargets");
const pages = targetInfos.filter((t) => t.type === "page");
const main = pages.find((t) => t.url.includes("127.0.0.1")) ?? pages[0];
if (!main) {
  console.error("no page target");
  process.exit(1);
}

const { sessionId } = await send("Target.attachToTarget", { targetId: main.targetId, flatten: true });
await send("Page.enable", {}, sessionId);
await send("Runtime.enable", {}, sessionId);
await send("Log.enable", {}, sessionId);

await send("Page.navigate", { url: URL_ }, sessionId);
// Runtime.enable replays the previous page's console buffer; drop it so the
// report only covers this load.
events.length = 0;
await new Promise((r) => setTimeout(r, SETTLE));

const state = await send(
  "Runtime.evaluate",
  {
    expression: `(() => {
      const root = document.querySelector('#root');
      const text = (root?.innerText || '').replace(/\\s+/g, ' ').trim();
      return JSON.stringify({
        url: location.href,
        title: document.title,
        rootChildren: root ? root.children.length : -1,
        rootBytes: root ? root.innerHTML.length : 0,
        textLength: text.length,
        textSample: text.slice(0, 500),
        bootstrapped: !!globalThis.__codexBootstrapped,
        hasShim: typeof globalThis.__codexHost,
      }, null, 1);
    })()`,
    returnByValue: true,
  },
  sessionId,
);

console.log("STATE:", state.result.value);
console.log(`\nEVENTS (${events.length}):`);
for (const e of events.slice(0, 60)) console.log("  " + e);

const shot = await send("Page.captureScreenshot", { format: "png" }, sessionId);
fs.writeFileSync(OUT, Buffer.from(shot.data, "base64"));
console.log(`\nscreenshot: ${OUT} (${fs.statSync(OUT).size} bytes)`);
ws.close();