Httpz – 零分配 HTTP/1.1 解析器，用于 OxCaml

Httpz – 零分配 HTTP/1.1 解析器，用于 OxCaml
Httpz – Zero-Allocation HTTP/1.1 Parser for OxCaml

## httpz: 一个零分配的 HTTP/1.1 解析器 & 服务器 httpz 是一个高性能的 HTTP/1.1 解析器和序列化器，使用 OxCaml 构建，旨在实现**零堆分配**。它通过无装箱类型、为记录和列表等数据结构使用本地栈分配，以及直接 bigstring I/O 来实现这一点。主要特性包括对完整 HTTP/1.1 的支持（方法、头部、分块编码、keep-alive），以及一个生产就绪、即将支持并行、异步静态文件服务器。基准测试表明，与基于 Eio 的解析器（如 `httpe`）相比，httpz 具有显著的速度提升和分配减少——对于小型请求，速度提升高达 3.14 倍，分配的字数减少 94 倍，并实现了 **14.6M 请求/秒的吞吐量**。 httpz 利用基于 span 的解析和预分配的缓冲区来提高效率。它需要 OxCaml 编译器 ([https://oxcaml.org/](https://oxcaml.org/))，并提供命令行工具用于服务器操作和基准测试。

## Httpz：为 OCaml 设计的零分配 HTTP/1.1 解析器一个名为 **Httpz** 的新型 HTTP/1.1 解析器，使用 OxCaml 扩展为 OCaml 构建，正在 Hacker News 上受到关注。其关键特性是 **零堆分配** – 解析结果存储在栈上，避免为每个请求产生垃圾回收开销。这是通过 OxCaml 的 ‘local’ 类型和解箱记录实现的。作者正在为 Httpz 添加无数据竞争的并行性，以便在其自己的 Web 服务器中使用，该服务器还利用 io_uring 实现零拷贝缓冲区和效果处理程序以实现高效的纤程恢复。讨论集中在 *为什么* 栈分配是有益的（提高速度和数据局部性等常数因子）以及大型头部可能导致的栈溢出等潜在缺点。开发者澄清说，当前实现具有无限制的栈增长，但计划将头部解析限制为应用程序请求的头部，从而降低风险。 OxCaml 允许开发者编写高性能的 OCaml 代码，最大限度地减少或消除垃圾回收，提供了一种反向的 Rust 式方法。

原文

A high-performance HTTP/1.1 parser and serializer that aims for zero heap allocations using OxCaml's unboxed types and local allocations.

Will soon have io_uring on Linux.

Zero heap allocations: Parser results are stack-allocated using OxCaml unboxed records and local lists
Direct bigstring I/O: Read and write directly to/from bigarray buffers
HTTP/1.1 support: Methods, headers, chunked transfer encoding, keep-alive
Async file server included: Production-ready static file server. Soon to be parallel.

httpz achieves zero-allocation parsing through:

Unboxed records (#{...}): Request and span types are stack-allocated
Local lists (@ local): Header list grows on the stack, not heap
Span-based parsing: Strings are referenced by offset+length into the input buffer
Pre-allocated buffers: 32KB read buffer reused across requests

Benchmarks comparing httpz (OxCaml) vs httpe (Eio-based parser):

Request Size	httpz (ns/op)	httpe (ns/op)	Speedup	Allocation Reduction
Small (35B)	69	218	3.14x	94x fewer words
Medium (439B)	792	1,690	2.13x	399x fewer words
Large (1155B)	1,771	4,017	2.27x	829x fewer words

Throughput: 14.6M requests/sec (vs 4.6M for httpe)

Operation	Time	Heap Allocations
Parse minimal request	209ns	3 words
Parse browser request (10 headers)	2.8μs	3 words
Parse 50 headers	7.7μs	3 words
Write status line	21ns	3 words
Write full response headers	62ns	3 words

Requires OxCaml compiler from https://oxcaml.org/

An Async-based static file server is included:

# Serve current directory on port 8080
dune exec bin/httpz_server.exe

# Serve specific directory on custom port
dune exec bin/httpz_server.exe -- -d /var/www -p 3000

# Get help
dune exec bin/httpz_server.exe -- -help

Features:

Async concurrent connection handling (up to 10,000 connections)
Zero-copy bigstring I/O
MIME type detection
Directory traversal protection
Automatic index.html for directories

# Comparative benchmark (httpz vs httpe)
dune exec bench/bench_compare.exe

# Detailed httpz benchmarks with core_bench
dune exec bench/bench_httpz.exe -- -quota 2

ISC

Httpz – 零分配 HTTP/1.1 解析器，用于 OxCaml Httpz – Zero-Allocation HTTP/1.1 Parser for OxCaml

Httpz – 零分配 HTTP/1.1 解析器，用于 OxCaml
Httpz – Zero-Allocation HTTP/1.1 Parser for OxCaml