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

Capture frames as PNGs during navigation
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

cloudflare-browser