Rust:axum学习笔记(2) response

上一篇的hello world里，示例过于简单，仅仅只是返回了一个字符串，实际上axum的response能返回各种格式，包括:

plain_text
html
json
http StatusCode
…

web开发中需要的各种格式，都能返回。talk is cheap ,show me the code！ 直接上代码：

bash;gutter:true; axum = "0.4.3" tokio = { version="1", features = ["full"] } serde = { version="1", features = ["derive"] } serde_json = "1" http = "0.2.1"</p> <pre><code> 这是依赖项，下面的代码主要来自[官方文档](https://docs.rs/axum/0.2.8/axum/#building-responses)，在此基础上补充了中文及"自定义错误"及"自定义结构"的返回示例(包括了web开发中大部分的常用返回格式) ;gutter:true;
use axum::{
body::{self,Body},
http::header::{HeaderMap, HeaderName, HeaderValue},
response::{Headers, Html, IntoResponse, Json,Response},
routing::get,
Router,
};
use http::{ StatusCode, Uri};
use serde::Serialize;
use serde_json::{json, Value};

// We’ve already seen returning &’static str
async fn plain_text() -> &’static str {
"foo"
}

// String works too and will get a text/plain; charset=utf-8 content-type
async fn plain_text_string(uri: Uri) -> String {
format!("Hi from {}", uri.path())
}

// Bytes will get a application/octet-stream content-type
async fn bytes() -> Vec {
vec![1, 2, 3, 4]
}

// () gives an empty response
async fn empty() {}

// StatusCode gives an empty response with that status code
async fn empty_with_status() -> StatusCode {
StatusCode::NOT_FOUND
}

// A tuple of StatusCode and something that implements IntoResponse can
// be used to override the status code
async fn with_status() -> (StatusCode, &’static str) {
(StatusCode::INTERNAL_SERVER_ERROR, "Something went wrong")
}

// A tuple of HeaderMap and something that implements IntoResponse can
// be used to override the headers
async fn with_headers() -> (HeaderMap, &’static str) {
let mut headers = HeaderMap::new();
headers.insert(
HeaderName::from_static("x-foo"),
HeaderValue::from_static("foo"),
);
(headers, "foo")
}

// You can also override both status and headers at the same time
async fn with_headers_and_status() -> (StatusCode, HeaderMap, &’static str) {
let mut headers = HeaderMap::new();
headers.insert(
HeaderName::from_static("x-foo"),
HeaderValue::from_static("foo"),
);
(StatusCode::INTERNAL_SERVER_ERROR, headers, "foo")
}

// Headers makes building the header map easier and impl Trait is easier
// so you don’t have to write the whole type
async fn with_easy_headers() -> impl IntoResponse {
Headers(vec![("x-foo", "foo")])
}

// Html gives a content-type of text/html
async fn html() -> Html {
Html("Hello, World!")
}

// Json gives a content-type of application/json and works with any type
// that implements serde::Serialize
async fn json() -> Json {
Json(json!({ "data": 42 }))
}

// Result where T and E implement IntoResponse is useful for
// returning errors
async fn result() -> Result {
Ok("all good")
}

// Response gives full control
async fn response() -> Response {
Response::builder().body(Body::empty()).unwrap()
}

#[derive(Serialize)]
struct Blog {
title: String,
author: String,
summary: String,
}

async fn blog_struct() -> Json {
let blog = Blog {
title: "axum笔记(2)-response".to_string(),
author: "菩提树下的杨过".to_string(),
summary: "response各种示例".to_string(),
};
Json(blog)
}

async fn blog_struct_cn() -> (HeaderMap, Json) {
let blog = Blog {
title: "axum笔记(2)-response".to_string(),
author: "菩提树下的杨过".to_string(),
summary: "response各种示例".to_string(),
};

let mut headers = HeaderMap::new();
headers.insert(
HeaderName::from_static("content-type"),
HeaderValue::from_static("application/json;charset=utf-8"),
);
(headers, Json(blog))
}

struct CustomError {
msg: String,
}

impl IntoResponse for CustomError {

fn into_response(self) -> Response {
let body= body::boxed(body::Full::from(self.msg));
Response::builder()
.status(StatusCode::INTERNAL_SERVER_ERROR)
.body(body)
.unwrap()
}
}

async fn custom_error() -> Result {
Err(CustomError {
msg: "Opps!".to_string(),
})
}

#[tokio::main]
async fn main() {
// our router
let app = Router::new()
.route("/plain_text", get(plain_text))
.route("/plain_text_string", get(plain_text_string))
.route("/bytes", get(bytes))
.route("/empty", get(empty))
.route("/empty_with_status", get(empty_with_status))
.route("/with_status", get(with_status))
.route("/with_headers", get(with_headers))
.route("/with_headers_and_status", get(with_headers_and_status))
.route("/with_easy_headers", get(with_easy_headers))
.route("/html", get(html))
.route("/json", get(json))
.route("/result", get(result))
.route("/response", get(response))
.route("/blog", get(blog_struct))
.route("/blog_cn", get(blog_struct_cn))
.route("/custom_error", get(custom_error));

// run it with hyper on localhost:3000
axum::Server::bind(&"0.0.0.0:3000".parse().unwrap())
.serve(app.into_make_service())
.await
.unwrap();
}

部分url的访问效果如上图，其它的就留给朋友们自己去尝试吧。注：网上传说的中文乱码问题，0.4.3新版本并没有出现，输出时已经自带了chatset=utf-8。

最后再补1个返回图片的示例：

cpp;gutter:true; use axum::{ routing::get, Router,http::header::{HeaderMap,HeaderValue,HeaderName} }; use std::fs::*;</p> <p>async fn image() -> (HeaderMap, Vec) { let mut headers = HeaderMap::new(); headers.insert( HeaderName::from_static("content-type"), HeaderValue::from_static("image/png"), ); (headers, read(String::from("/Users/Downloads/avatar.png")).unwrap()) }

参考链接：

https://docs.rs/axum/0.4.3/axum/response/trait.IntoResponse.html

https://docs.rs/axum/0.2.8/axum/#building-responses

Original: https://www.cnblogs.com/yjmyzz/p/axum_tutorial_2_response.html
Author: 菩提树下的杨过
Title: Rust:axum学习笔记(2) response