Rust 中如何使用 reqwest 发送 HTTP 请求？

推荐答案

// www.javascriptcn.com code example
use reqwest::blocking::get;
use reqwest::Error;

fn main() -> Result<(), Error> {
    let url = "https://api.example.com/data";
    let response = get(url)?;

    if response.status().is_success() {
        let body = response.text()?;
        println!("Response body: {}", body);
    } else {
        println!("Request failed with status: {}", response.status());
    }

    Ok(())
}

本题详细解读

1. 引入 reqwest 库

首先，需要在 Cargo.toml 文件中添加 reqwest 依赖：

[dependencies]
reqwest = { version = "0.11", features = ["blocking"] }

2. 使用 reqwest::blocking::get 发送 GET 请求

reqwest::blocking::get 是一个同步的 HTTP GET 请求方法。它接受一个 URL 字符串作为参数，并返回一个 Result<Response, Error>。

let response = get(url)?;

3. 处理响应

通过 response.status() 可以获取 HTTP 响应的状态码。is_success() 方法用于判断请求是否成功（状态码为 2xx）。

if response.status().is_success() {
    let body = response.text()?;
    println!("Response body: {}", body);
} else {
    println!("Request failed with status: {}", response.status());
}

4. 处理错误

reqwest 使用 Result 类型来处理可能的错误。通过 ? 操作符可以将错误向上传播，或者在 main 函数中返回 Result<(), Error> 来处理错误。

fn main() -> Result<(), Error> {
    // ...
    Ok(())
}

5. 异步请求

如果需要发送异步请求，可以使用 reqwest 的异步 API。首先需要在 Cargo.toml 中启用 tokio 运行时：

[dependencies]
reqwest = { version = "0.11", features = ["json"] }
tokio = { version = "1", features = ["full"] }

然后使用 reqwest::get 发送异步请求：

// www.javascriptcn.com code example
use reqwest::Error;

#[tokio::main]
async fn main() -> Result<(), Error> {
    let url = "https://api.example.com/data";
    let response = reqwest::get(url).await?;

    if response.status().is_success() {
        let body = response.text().await?;
        println!("Response body: {}", body);
    } else {
        println!("Request failed with status: {}", response.status());
    }

    Ok(())
}

6. 其他 HTTP 方法

reqwest 还支持其他 HTTP 方法，如 POST、PUT、DELETE 等。可以通过 reqwest::blocking::Client 或 reqwest::Client 来构建请求：

// www.javascriptcn.com code example
use reqwest::blocking::Client;
use reqwest::Error;

fn main() -> Result<(), Error> {
    let client = Client::new();
    let response = client.post("https://api.example.com/data")
        .body("data")
        .send()?;

    if response.status().is_success() {
        let body = response.text()?;
        println!("Response body: {}", body);
    } else {
        println!("Request failed with status: {}", response.status());
    }

    Ok(())
}