caching-proxy

A lightweight CLI-based HTTP caching proxy server. Forward requests to any origin URL and cache responses in memory — repeat requests are served instantly without hitting the origin again.

Features

• In-memory response caching with x-cache hit/miss headers
• Transparent forwarding of any GET request to a configurable origin
• Cache invalidation via a --clear-cache flag
• Port validation and clear startup error messages

Installation

npm install

Usage

node index.js --port <port> --origin <url>

Options

Flag	Short	Type	Description
--port	-p	string	Port to listen on (default: 3000)
--origin	-o	string	Origin URL to forward requests to (required)
--clear-cache	—	boolean	Clears the in-memory cache and exits

Examples

# Start proxy on port 3000 forwarding to an API
node index.js --port 3000 --origin https://api.example.com

# Use short flags
node index.js -p 8080 -o https://jsonplaceholder.typicode.com

# Clear the cache
node index.js --clear-cache

How It Works

1. A request comes in (e.g. GET /users/1)
2. The proxy constructs the full URL: <origin>/users/1
3. If the URL is cached, it responds immediately with x-cache: HIT
4. If not, it fetches from the origin, caches the response, and returns it with x-cache: MISS

Response Headers

Header	Value	Meaning
x-cache	HIT	Response served from in-memory cache
x-cache	MISS	Response fetched from origin

Dependencies

• express — HTTP server
• axios — HTTP client for origin requests

Notes

• Cache is in-memory only — it resets when the process restarts

• Only GET requests are proxied

• Port must be a valid number between 0–65535

• project file: