HCS Documentation#

HCS is an HTTP library for OCaml 5+ built on Eio. It provides HTTP/1.1, HTTP/2, and WebSocket support for both clients and servers.

Getting Started#

New to HCS? Start here:

1. Installation - Set up HCS in your project
2. Your First Server - Build a simple HTTP server
3. Your First Client - Make HTTP requests

Guides#

Learn the core concepts:

• Request Lifecycle - How requests flow through HCS
• Routing - Map URLs to handlers with path parameters
• Plug System - Compose middleware pipelines
• Responses - Build responses and stream data
• Error Handling - Handle errors gracefully

HTTP Client#

Using HCS as an HTTP client:

• Basic Requests - GET, POST, headers, and bodies
• HTTP/2 - HTTP/2 multiplexing and server push
• Connection Pooling - Reuse connections efficiently
• TLS Configuration - Certificates and security settings

Real-time#

Build real-time applications:

• WebSocket - Bidirectional communication
• Server-Sent Events - Server-to-client streaming
• PubSub - Topic-based message broadcasting
• Channels - Multiplexed WebSocket conversations

Plugs#

The middleware system:

• Overview - What plugs are and how they compose
• Writing Plugs - Create custom middleware

Recipes#

Common patterns and solutions:

• Authentication - Sessions, basic auth, CSRF
• Rate Limiting - Protect against abuse
• CORS - Cross-origin resource sharing
• Static Files - Serve files from disk
• JSON APIs - Content negotiation and JSON responses