Interception Proxy

Web service to create proxies for intercepting and manipulating WebSocket traffic between an Ably client library and the Realtime service. Very much a prototype and a work in progress (see the abundant TODOs in the code). The motivation for this work is currently best described by this internal RFC.

Requirements

• Node LTS — I tested on 20
• Python 3.x — I tested on 3.12.4
• mitmproxy (PyPi) — I tested on 10.3.1
• websockets (PyPi) — I tested on 12.0

Installation

There are currently no NPM releases of this package, so you’ll need to install it directly from the Git repo:

npm install https://github.com/ably-labs/interception-proxy

Commands

Setup

• npx --package interception-proxy generate-mitmproxy-certs: Generates the mitmproxy TLS certificate, so that you can add it to the trust store used by the process under test.

Running locally

• npx interception-proxy: Starts the interception proxy. Use this when running in a local development environment.

Running in CI

• npx --package interception-proxy start-service: Starts the interception proxy as a background service. Useful for CI. The script uses sudo so it’s probably not something you want to use locally.

JSON-RPC API

See docs/API.md.

Examples

Currently the best example of how to use this server is ably/ably-js#1816.