Endpoint Pass-through

A serverless API endpoint proxy pass-through, currently designed to work specifically with Cloudflare Workers.

The objective of this project is to provide a small and lightweight package that can securely proxy connections from specific hostnames or IPs, allowing frontend apps to call APIs of various services without exposing secret keys.

sequenceDiagram
    participant Source as Source
    participant Worker as Worker
    participant Destination as Destination

    Source->>Worker: request
    Worker->>Destination: proxied Request
    Destination-->>Worker: response
    Worker-->>Source: proxied response

Usage

• Create a Cloudflare Workers account
• Fork or clone this repo so that you can customize it to your specific use case
• Within Cloudflare, create and include a key and add it to the wrangler.toml config file in the account_id variable
• Set up your environment variables for the secret keys needed for your APIs. This can be done in the Cloudflare dashboard under the Workers tab.
• Add some custom endpoints in config.js under endpoints
• Optionally, add allow-listed sources in config.js under allowedList (currently IPv4 and FQDN is supported, but not IPv6)
• Build with npm run build
• Start locally with npm run start
• Deploy to a worker instance with npm run ship
• Query your worker URL from a suitable client machine, and append the api param to the request

Features

• API pass through for any number of endpoints
• Compatibility with various http methods: GET, POST, PUT and DELETE
• IPv4 and domain-based allow-list to filter requests
• Param preservation, where parameters are not stripped and are passed to the target endpoint request
• Response proxying, where the response is fully preserved when passed back to the source (client node), including HTTP code and header data
• Caching, a 30 second cache is included by default and uses Cloudflare's native cache API

Todo

• Additional features to consider
  • Checking the Origin and Referer headers
  • DNS TXT record verification
  • Rate limiting