Caching Proxy

A Spring Boot-based HTTP caching proxy server that caches responses from an upstream server using Redis.

Features

• HTTP Proxy: Forwards GET requests to a configurable upstream server
• Redis Caching: Caches responses with configurable TTL to reduce upstream load
• Cache Management: Clear cache endpoint for manual cache invalidation
• Cache Headers: Responses include X-Cache header (HIT/MISS) to indicate cache status

Prerequisites

• Java 21
• Maven
• Redis (via Docker Compose)

Configuration

Set the following environment variables:

• PROXY_UPSTREAM_SERVER_HOST - The upstream server URL to proxy
• REDIS_HOST - Redis server hostname
• REDIS_PORT - Redis server port
• CACHE_DURATION_SECONDS - Cache TTL in seconds

Quick Start

1. Start Redis:

   docker-compose up -d

2. Set environment variables:

   export PROXY_UPSTREAM_SERVER_HOST=http://example.com
   export REDIS_HOST=localhost
   export REDIS_PORT=6379
   export CACHE_DURATION_SECONDS=300

3. Run the application:

   ./mvnw spring-boot:run

API Endpoints

• GET /** - Proxy any GET request to the upstream server with caching
• POST /clear - Clear all cached responses

How It Works

1. Client sends GET request to the proxy
2. Proxy checks Redis cache for the URL
3. On cache miss: fetches from upstream server, stores in Redis, returns response
4. On cache hit: returns cached response directly
5. All responses include X-Cache: HIT or X-Cache: MISS header

Technology Stack

• Spring Boot 3.5.9
• Spring Data Redis
• Java 21
• Redis 7.4.1