GA4 Proxy Worker

This project is a Cloudflare Worker script designed to act as a proxy for Google Analytics 4 (GA4) data collection and provide additional features like modifying analytics script behavior. The script integrates and modifies the lightweight analytics script from the Minimal Analytics project to suit custom requirements.

Features

1. GA4 Proxy:

   • Proxies data to the GA4 collection endpoint, ensuring the MEASUREMENT_ID matches the one configured in the environment.

2. Custom Analytics Script:

   • Fetches the analytics script from the Minimal Analytics project.
   • Modifies the script to replace the default GA4 endpoint with the worker’s proxy endpoint.
   • Adds a fallback mechanism for analytics data collection.

3. CORS Support:

   • Handles cross-origin requests, including preflight OPTIONS requests.

4. Flexible Data Handling:

   • Supports GET and POST requests for data collection.
   • Provides fallback methods for sending analytics data.

5. Image Pixel Response:

   • Returns a transparent 1x1 image for successful GET requests, emulating traditional pixel tracking.

Modifications to Original Script

This project integrates the analytics script from the Minimal Analytics project by Jack Hill, which is licensed under the MIT License. Modifications include:

• Replacing the default Google Analytics endpoint with a custom proxy endpoint.
• Adding fallback logic for alternative methods of sending analytics data.

Installation

1. Setup Cloudflare Workers:

   • Deploy the provided script using Cloudflare‘s dashboard or the Wrangler CLI.

2. Environment Variables:

   • Configure the following variable in your worker environment:
     • MEASUREMENT_ID: Your Google Analytics 4 measurement ID.

Usage

1. Proxying Analytics Data

• Send GET or POST requests to the worker’s URL with query parameters required by GA4. The worker will forward the data to the GA4 endpoint.

2. Serving Modified Analytics Script

• Append the ?fallback=true query parameter to the worker‘s URL to fetch the modified analytics script.

Example Requests

Proxy Data Collection

curl -X POST https://<worker-url> \
  -H "Content-Type: application/json" \
  -d '{"tid":"G-XXXXXXX", "cid":"123456", "t":"event", "en":"test_event"}'

Fetch Modified Script

curl https://<worker-url>?fallback=true

License

This project is licensed under the MIT License.
It integrates and modifies the analytics script from the Minimal Analytics project by Jack Hill, which is also licensed under the MIT License.