Rust HTTP Stack Overview

This article answers the question: How does HTTP protocol implement in Rust?

We summarized the core crates that make up the Rust web development stack: httparse, http, http-body, hyper, tower, tower-http, and axum, including their purpose, functionality, and direct dependencies.

Crates

📦 1. httparse

• Purpose: Minimal, high-performance HTTP request/response parser.
• Functionality:
  • Parses raw TCP bytes into HTTP headers (excluding body).
  • Supports basic structure parsing of HTTP/1.1 requests and responses.
• Direct Dependencies: None.
• Used by: hyper for low-level HTTP parsing.

📦 2. http

• Purpose: Provides common HTTP type definitions (no logic implementation).
• Functionality:
  • Defines generic Request<T> / Response<T> types.
  • Includes Method, HeaderMap, StatusCode, etc.
• Direct Dependencies: Standard library only.
• Used by: hyper, tower, axum, http-body, and more.

📦 3. http-body

• Purpose: Defines traits for streaming HTTP bodies.
• Functionality:
  • The Body trait describes async body sources.
  • Supports incremental data consumption (e.g., file downloads, streaming responses).
• Direct Dependencies:
  • http (for HeaderMap and types)
  • bytes (for Buf trait)
• Used by: hyper, axum, some tower middleware.

📦 4. hyper

• Purpose: High-performance, asynchronous HTTP client and server.
• Functionality:
  • Full HTTP/1.1 and HTTP/2 support.
  • Based on http and http-body types.
• Direct Dependencies (core parts):
  • http, http-body, httparse
  • tokio, bytes, futures
• Used by: axum, warp, and other frameworks.

📦 5. tower

• Purpose: Composable middleware abstraction layer.
• Functionality:
  • Defines the Service<Request> -> Future<Response> trait.
  • Supports composing middleware, retries, load balancing, etc.
• Direct Dependencies:
  • futures, pin-project, tracing
• Used by: axum, tower-http.

📦 6. tower-http

• Purpose: A set of HTTP-focused middleware built on tower.
• Functionality:
  • Provides CORS, compression, timeout, rate limiting, tracing, etc.
• Direct Dependencies:
  • tower
  • http
  • http-body
  • headers, tokio, bytes, etc.
• Used by: axum

📦 7. axum

• Purpose: Modern, type-safe Rust web framework.
• Functionality:
  • Provides routing, request extractors, response wrappers, state management.
  • Built on tower middleware and uses hyper as the underlying server.
• Direct Dependencies:
  • hyper
  • tower, tower-http
  • http, http-body
  • tokio, futures, bytes, serde

Composition Overview

┌──────────────┐
│  Your App    │  → axum handlers, routes, extractors
└──────┬───────┘
       ↓
   [axum (web framework)]
       ↓
[tower + tower-http (middleware stack)]
       ↓
  hyper (http server/client)
       ↓
 http (types) + http-body (Body trait)
       ↓
    httparse (parsing)
       ↓
    TcpStream(provided by tokio)