cloudflare-browser

name	cloudflare-browser
description	Control headless Chrome via Cloudflare Browser Rendering CDP WebSocket. Use for screenshots, page navigation, scraping, and video capture when browser automation is needed in a Cloudflare Workers environment. Requires CDP_SECRET env var and cdpUrl configured in browser.profiles.

Cloudflare Browser Rendering

Control headless browsers via Cloudflare's Browser Rendering service using CDP (Chrome DevTools Protocol) over WebSocket.

Prerequisites

• CDP_SECRET environment variable set
• Browser profile configured in openclaw.json with cdpUrl pointing to the worker endpoint:

  "browser": {
    "profiles": {
      "cloudflare": {
        "cdpUrl": "https://your-worker.workers.dev/cdp?secret=..."
      }
    }
  }
  

Quick Start

Screenshot

node /path/to/skills/cloudflare-browser/scripts/screenshot.js https://example.com output.png

Multi-page Video

node /path/to/skills/cloudflare-browser/scripts/video.js "https://site1.com,https://site2.com" output.mp4

CDP Connection Pattern

The worker creates a page target automatically on WebSocket connect. Listen for Target.targetCreated event to get the targetId:

const WebSocket = require("ws");
const CDP_SECRET = process.env.CDP_SECRET;
const WS_URL = `wss://your-worker.workers.dev/cdp?secret=${encodeURIComponent(CDP_SECRET)}`;

const ws = new WebSocket(WS_URL);
let targetId = null;

ws.on("message", data => {
  const msg = JSON.parse(data.toString());
  if (msg.method === "Target.targetCreated" && msg.params?.targetInfo?.type === "page") {
    targetId = msg.params.targetInfo.targetId;
  }
});

Key CDP Commands

Command	Purpose
Page.navigate	Navigate to URL
Page.captureScreenshot	Capture PNG/JPEG
Runtime.evaluate	Execute JavaScript
Emulation.setDeviceMetricsOverride	Set viewport size

Common Patterns

Navigate and Screenshot

await send("Page.navigate", { url: "https://example.com" });
await new Promise(r => setTimeout(r, 3000)); // Wait for render
const { data } = await send("Page.captureScreenshot", { format: "png" });
fs.writeFileSync("out.png", Buffer.from(data, "base64"));

Scroll Page

await send("Runtime.evaluate", { expression: "window.scrollBy(0, 300)" });

Set Viewport

await send("Emulation.setDeviceMetricsOverride", {
  width: 1280,
  height: 720,
  deviceScaleFactor: 1,
  mobile: false,
});

Creating Videos

1. Capture frames as PNGs during navigation
2. Use ffmpeg to stitch: ffmpeg -framerate 10 -i frame_%04d.png -c:v libx264 -pix_fmt yuv420p output.mp4

Troubleshooting

• No target created: Race condition - wait for Target.targetCreated event with timeout
• Commands timeout: Worker may have cold start delay; increase timeout to 30-60s
• WebSocket hangs: Verify CDP_SECRET matches worker configuration