reqwest 是一個用于 Rust 的強大 HTTP 客戶端庫，它允許你輕松地進行 HTTP 請求。以下是 reqwest 的一些常見用法：

1. 發送 GET 請求：

use reqwest::Error;

async fn get_request() -> Result<String, Error> {
    let response = reqwest::get("https://api.example.com/data")
        .await?
        .text()
        .await?;
    Ok(response)
}

2. 發送 POST 請求：

use reqwest::{Client, Error};
use serde_json::json;

async fn post_request() -> Result<String, Error> {
    let client = Client::new();
    let data = json!({
        "key": "value",
    });

    let response = client.post("https://api.example.com/data")
        .json(&data)
        .send()
        .await?
        .text()
        .await?;
    Ok(response)
}

3. 添加請求頭：

use reqwest::Error;

async fn request_with_headers() -> Result<String, Error> {
    let client = Client::new();
    let response = client.get("https://api.example.com/data")
        .header("Authorization", "Bearer your_token")
        .header("Custom-Header", "custom_value")
        .send()
        .await?
        .text()
        .await?;
    Ok(response)
}

4. 超時設置：

use reqwest::Error;
use std::time::Duration;

async fn request_with_timeout() -> Result<String, Error> {
    let client = Client::builder()
        .timeout(Duration::from_secs(5))
        .build()?;

    let response = client.get("https://api.example.com/data")
        .send()
        .await?
        .text()
        .await?;
    Ok(response)
}

5. 錯誤處理：

use reqwest::Error;

async fn handle_error() {
    match reqwest::get("https://api.example.com/data")
        .await
    {
        Ok(response) => {
            if response.status().is_success() {
                let body = response.text().await?;
                println!("Success! Body: {}", body);
            } else {
                eprintln!("Error: {}", response.status());
            }
        }
        Err(e) => eprintln!("Request failed: {}", e),
    }
}

6. 同步請求（不推薦）：

use reqwest::Error;

fn sync_request() -> Result<String, Error> {
    let response = reqwest::get("https://api.example.com/data")
        .send()?
        .text()?;
    Ok(response)
}

這些示例展示了如何使用 reqwest 庫執行基本的 HTTP 請求。你可以根據自己的需求進行調整，例如使用不同的 HTTP 方法、處理響應數據等。