Rust 隧道代理：reqwest 与 isahc 两种实现

reqwest

reqwest 是 Rust 最流行的 HTTP 客户端，通过 Proxy::all 配置代理。注意：reqwest 不支持 在 HTTPS CONNECT 阶段注入自定义头，因此 HTTPS Proxy-Tunnel 无效。

use reqwest::{Proxy, Client};
use std::env;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let host = env::var("PROXY_HOST").unwrap_or_else(|_| "t.16yun.cn".into());
    let port = env::var("PROXY_PORT").unwrap_or_else(|_| "31111".into());
    let user = env::var("PROXY_USERNAME").unwrap_or_else(|_| "user".into());
    let pass = env::var("PROXY_PASSWORD").unwrap_or_else(|_| "password".into());

    let proxy_url = format!("http://{}:{}@{}:{}", user, pass, host, port);
    let proxy = Proxy::all(&proxy_url)?;

    let client = Client::builder()
        .proxy(proxy)
        .timeout(std::time::Duration::from_secs(15))
        .build()?;

    let resp = client.get("https://httpbin.org/ip").send().await?;
    println!("{}", resp.text().await?);

    Ok(())
}

Proxy-Tunnel 限制

// HTTP Proxy-Tunnel（有效）
let resp = client.get("http://httpbin.org/ip")
    .header("Proxy-Tunnel", "rust-demo")
    .send().await?;

// HTTPS Proxy-Tunnel（无效——reqwest 不支持 CONNECT 阶段自定义头）
let resp = client.get("https://httpbin.org/ip")
    .header("Proxy-Tunnel", "rust-demo") // 这个头不会在 CONNECT 阶段发送
    .send().await?;

如需 HTTPS Proxy-Tunnel，考虑 Go（Transport.ProxyConnectHeader）或 Python httpx（httpx.Proxy(headers=...)）。

isahc

isahc 基于 libcurl，支持更多代理特性：

use isahc::{HttpClient, Request, auth::Authentication};
use std::env;

fn main() -> Result<(), isahc::Error> {
    let host = env::var("PROXY_HOST").unwrap_or_else(|_| "t.16yun.cn".into());
    let port = env::var("PROXY_PORT").unwrap_or_else(|_| "31111".into());
    let user = env::var("PROXY_USERNAME").unwrap_or_else(|_| "user".into());
    let pass = env::var("PROXY_PASSWORD").unwrap_or_else(|_| "password".into());

    let client = HttpClient::builder()
        .proxy(Some(format!("http://{}:{}", host, port).parse().unwrap()))
        .proxy_authentication(Authentication::basic(user, pass))
        .timeout(std::time::Duration::from_secs(15))
        .build()?;

    let resp = client.get("https://httpbin.org/ip")?;
    println!("{}", resp.text()?);

    Ok(())
}

reqwest vs isahc