如何修复actix_web中“{function}没有实现特征函数，_，_>”错误？

Question

我有这个简单的代码：

use actix_web::{get, post, web, App, HttpResponse, HttpServer, Responder};
use serde::{Deserialize, Serialize};
use serde_json::{json};
use validator::{Validate, ValidationError};

#[derive(Deserialize, Serialize, Validate)]
struct Auth {
    #[validate(length(min = 4))]
    username: String,
    password: String,
}

#[post("/auth")]
async fn auth(form: web::Json<Auth>) -> Result<serde_json::Value, ValidationError> {
    Ok(json!{ "success" })
}

这一直给我这个错误：

error[E0277]: the trait bound `fn(Json<Auth>) -> impl std::future::Future {auth}: Factory<_, _, _>` is not satisfied
  --> src/main.rs:77:10
   |
77 | async fn auth(form: web::Json<Auth>) -> Result<serde_json::Value, ValidationError> {
   |          ^^^^ the trait `Factory<_, _, _>` is not implemented for `fn(Json<Auth>) -> impl std::future::Future {auth}`

我做错了什么？

Answer 1

我想通了。将Result<serde_json::Value, ValidationError>更改为HttpResponse并在HttpResponse中返回json就可以了。

#[post("/auth")]
async fn auth(form: web::Json<Auth>) -> HttpResponse {
    match form.validate() {
        Ok(_) => HttpResponse::Ok().json(json!{ {"success":true}}),
        Err(e) => HttpResponse::NotAcceptable().body(format!("{}", e))
    }
}