printer

printer — MITM Proxy Example Tool

A complete CLI MITM proxy example demonstrating all features of the proxy package. It prints intercepted traffic (HTTP, WebSocket, TCP) to stdout.

Quick Start

go run main.go

The proxy listens on 0.0.0.0:8080. Configure your browser or system proxy to point here.

Cross Compile

# Linux
GOOS=linux GOARCH=amd64 go build -o proxy main.go

# Windows
GOOS=windows GOARCH=amd64 go build -o proxy.exe main.go

# macOS
GOOS=darwin GOARCH=amd64 go build -o proxy main.go

What It Demonstrates

This example hooks all four matcher types to log traffic:

Matcher	Purpose
WithReqMatcher	Logs HTTP requests
WithRespMatcher	Logs HTTP responses
WithWsMatcher	Logs WebSocket frames (handles unmasking)
WithRawMatcher	Logs raw TCP data

Configuration

The tool uses the embedded development CA certificate (proxy.Certificate + proxy.PrivateKey). For production, replace with your own CA or use proxy.FromSelfSigned().

To chain an upstream proxy, set conf.Dialer before ListenAndServe:

dialer, _ := proxy.SOCKS5("tcp", "127.0.0.1:10808", nil, nil)
conf.Dialer = dialer

Notes

• Default log level is TraceLevel to show all details
• Client-side TLS verification is disabled (InsecureSkipVerify = true)
• Default SNI fallback: www.google.com