如何在Axum中同时使用axum::extract::Query与axum::extract::State？

问题根源 #

编译失败的核心原因是枚举MyParams的serde反序列化 trait 拼写错误，同时需确保类型满足Query提取器的要求：

• serde::Deserialze 应为 serde::Deserialize（少了一个r）
• Query提取器要求目标类型实现serde::Deserialize<'de>，需保证derive宏正确生成代码

修正步骤 #

1. 修复serde依赖配置
   确保Cargo.toml中serde启用derive特性：

   [dependencies]
   axum = "0.7"
   serde = { version = "1.0", features = ["derive"] }
   tokio = { version = "1.0", features = ["full"] }
   

2. 修正MyParams的derive宏
   修正拼写错误并移除无关trait（ValueEnum是clap命令行参数解析用的，和HTTP查询参数提取无关）：

   #[derive(Clone, Debug, serde::Deserialize, serde::Serialize)]
   pub enum MyParams {
       Normal,
       Verbose,
   }
   

3. 确保处理器函数的提取器导入正确
   处理器需导入Axum的State和Query提取器：

   use axum::{extract::{State, Query}, Json, StatusCode};
   use std::sync::Arc;
   
   async fn path(
       State(middle_ware): State<Arc<MyState>>,
       params: Query<MyParams>
   ) -> impl IntoResponse {
       println!("{:?}", params);
       let result = middle_ware.process().await;
       (StatusCode::OK, Json(result))
   }
   

完整可运行代码示例 #

use axum::{
    extract::{State, Query},
    Json, Router, Server,
};
use serde::{Deserialize, Serialize};
use std::net::SocketAddr;
use std::sync::Arc;

#[derive(Clone, Debug, Deserialize, Serialize)]
pub enum MyParams {
    Normal,
    Verbose,
}

#[derive(Debug)]
pub struct MyState {
    port: u16,
}

impl MyState {
    pub async fn process(&self) -> String {
        format!("Processing on port {}", self.port)
    }
}

impl MyState {
    pub async fn serve(self) {
        let port = self.port;
        let app = Router::new()
            .route("/path", axum::routing::get(path))
            .with_state(Arc::new(self));

        let addr = SocketAddr::from(([127, 0, 0, 1], port));
        Server::bind(&addr)
            .serve(app.into_make_service())
            .await
            .unwrap();
    }
}

async fn path(
    State(middle_ware): State<Arc<MyState>>,
    params: Query<MyParams>
) -> impl IntoResponse {
    println!("{:?}", params);
    let result = middle_ware.process().await;
    (StatusCode::OK, Json(result))
}

验证方式 #

启动服务后，访问http://localhost:指定端口/path?MyParams=Normal或http://localhost:指定端口/path?MyParams=Verbose，即可正常提取查询参数与状态。

内容的提问来源于stack exchange，提问作者Finlay Weber