Async Lightweight HTTP Client (aka ALHC)

WARNING

This library is still in development and VERY UNSTABLE, please don't use it in production environment.

What if we need async but also lightweight http client without using such a large library like reqwest, isahc or surf?

ALHC is a async http client library that using System library to reduce binary size and provide async request feature.

HTTPS Example:

use alhc::prelude::*;
use alhc::*;

use pollster::FutureExt;

fn main() -> DynResult {
    let client = get_client_builder().build().unwrap();

    let r = client
        .post("https://httpbin.org/anything")?
        .header("user-agent", "alhc/0.2.0")
        .body_string("Hello World!".repeat(20))
        .block_on()?
        .recv_string()
        .block_on()?;

    println!("{r}");

    Ok(())
}

Our little request example https with release build can be 182 KB, which is smaller than tinyget's http example. If we use rustc nightly feature plus build-std and panic_immediate_abort, it'll be incredibly 65 KB!

Currently work in progress and supports Windows through WinHTTP and Unix-like systems through the system libcurl. The Unix backend uses libcurl's Multi API: each client has one lightweight driver thread shared by all of its concurrent requests, without depending on a specific async runtime.

Platform Status

Name	Status	Note
Windows	Working	Async WinHTTP backend
macOS	Working	System libcurl Multi backend, one driver per client
Linux	Working	System libcurl Multi backend, one driver per client

Features

• async_t_boxed: Use async-trait instead of async-t, which requires 1.75+ version of rustc but with zero-cost. Default is disabled.
• serde: Can give you the ability of send/receive json data without manually call serde_json. Default is disabled.
• anyhow: Use Result type from anyhow crate instead Result<T, Box<dyn std::error::Error>>. Default is disabled.

Minimum binary size on Unix-like platforms

The Unix backend links directly and dynamically to the system libcurl, keeping curl out of the executable for a smaller release binary.

• macOS: the system libcurl is used automatically.
• Linux and other Unix-like systems: make sure the linker can resolve -lcurl and that the shared library is available at runtime. On Ubuntu/Debian, install libcurl4-openssl-dev.

Compilation binary size comparison

Note: the measurements use cargo +nightly build --target [TARGET] --examples, cargo +nightly build --release --target [TARGET] --examples, and cargo +nightly build --release -Z build-std=core,alloc,std,panic_abort --target [TARGET] --examples, together with the release profile in Cargo.toml. Because panic = "immediate-abort" requires a matching standard library, the regular release measurements use panic = "abort"; the size-optimized measurements use the configured immediate-abort strategy with build-std.

Name	Windows (x86_64)	Windows (i686)	Windows (aarch64)	macOS (x86_64)	macOS (aarch64)	Linux (x86_64)
example https	468,992	402,944	296,960	955,776	997,928	18,051,064
example https release	181,248	162,816	200,192	315,160	321,680	850,704
example https release with size optimization	75,264	66,048	59,392	62,744	88,208	465,480
example parallel	571,904	486,912	393,216	1,153,736	1,205,304	19,612,824
example parallel release	190,464	170,496	229,888	323,480	321,808	862,992
example parallel release with size optimization	80,896	71,680	66,560	66,952	104,816	469,576
example sequential	472,064	405,504	302,080	959,440	997,464	18,048,624
example sequential release	182,784	164,864	203,264	315,240	321,760	850,704
example sequential release with size optimization	76,800	68,096	60,928	62,816	104,752	465,480