使用 Rust 调用 REST API

JSON : Placeholder

JSON : Placeholder (https://jsonplaceholder.typicode.com/) 是一个用于测试的 REST API 网站。
以下使用 Rust 调用该网站的 REST API，获取字符串以及 JSON 数据。

• GET /posts/1
• GET /posts
• POST /posts
• PUT /posts/1
• DELETE /posts/1

所有 GET API 都返回JSON数据，格式（JSON-Schema）如下：

{
  "type":"object",
  "properties": {
    "userId": {"type" : "integer"},
    "id": {"type" : "integer"},
    "title": {"type" : "string"},
    "body": {"type" : "string"}
  }
}

Rust

Cargo.toml

[package]
...

[dependencies]
serde = { version = "1.0", features = ["derive"] }
serde_json = "1.0"
reqwest = { version = "0.10.8", features = ["json"] }
tokio = { version = "0.2.22", features = ["rt-threaded", "macros"] }

main.rust

use std::error::Error;
use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize, Debug, Clone)]
struct Post {
    #[serde(rename(serialize = "userId", deserialize = "userId"))]
    user_id: i32,
    id: i32,
    title: String,
    body: String,
}

const BASE_URL: &str = "http://jsonplaceholder.typicode.com/";

async fn get_post_as_string() -> Result<String, Box<dyn Error>> {
    let url = format!("{}posts/1", BASE_URL);
    let s = reqwest::get(&url).await?.text().await?;
    Ok(s)
}

async fn get_post_as_json() -> Result<Post, Box<dyn Error>> {
    let url = format!("{}posts/1", BASE_URL);
    let v: Post = reqwest::get(&url).await?.json().await?;
    Ok(v)
}

async fn get_posts() -> Result<Vec<Post>, Box<dyn Error>> {
    let url = format!("{}posts", BASE_URL);
    let v: Vec<Post> = reqwest::get(&url).await?.json().await?;
    let v = v[0..2].to_vec();
    Ok(v)
}

async fn create_post() -> Result<String, Box<dyn Error>> {
    let url = format!("{}posts", BASE_URL);
    let o = Post {
        user_id: 1,
        id: 0,
        title: "test title".to_string(),
        body: "test body".to_string()
    };
    let s = reqwest::Client::new().post(&url).body(serde_json::to_string(&o)?).send().await?.text().await?;
    Ok(s)
}

async fn update_post() -> Result<String, Box<dyn Error>> {
    let url = format!("{}posts/1", BASE_URL);
    let o = Post {
        user_id: 1,
        id: 1,
        title: "test title".to_string(),
        body: "test body".to_string()
    };
    let s = reqwest::Client::new().put(&url).body(serde_json::to_string(&o)?).send().await?.text().await?;
    Ok(s)
}

async fn delete_post() -> Result<String, Box<dyn Error>> {
    let url = format!("{}posts/1", BASE_URL);
    let s = reqwest::Client::new().delete(&url).send().await?.text().await?;
    Ok(s)
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    println!("{}", get_post_as_string().await?);
    println!("{:?}", get_post_as_json().await?);
    println!("{:?}", get_posts().await?);
    println!("{}", create_post().await?);
    println!("{}", update_post().await?);
    println!("{}", delete_post().await?);

    Ok(())
}

• get_post_as_string 函数取出第1个Post，返回字符串
• get_post_as_json 函数取出第1个Post，返回Post对象
• get_posts 函数取出前2个Post，返回2个Post对象
• create_post 函数创建1个Post，返回字符串
• update_post 函数更新第1个Post，返回字符串
• delete_post 函数删除第1个Post，返回字符串

输出

程序执行后的输出为

{
  "userId": 1,
  "id": 1,
  "title": "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
  "body": "quia et suscipit
suscipit recusandae consequuntur expedita et cum
reprehenderit molestiae ut ut quas totam
nostrum rerum est autem sunt rem eveniet architecto"
}
Post { user_id: 1, id: 1, title: "sunt aut facere repellat provident occaecati excepturi optio reprehenderit", body: "quia et suscipit
suscipit recusandae consequuntur expedita et cum
reprehenderit molestiae ut ut quas totam
nostrum rerum est autem sunt rem eveniet architecto" }
[Post { user_id: 1, id: 1, title: "sunt aut facere repellat provident occaecati excepturi optio reprehenderit", body: "quia et suscipit
suscipit recusandae consequuntur expedita et cum
reprehenderit molestiae ut ut quas totam
nostrum rerum est autem sunt rem eveniet architecto" }, Post { user_id: 1, id: 2, title: "qui est esse", body: "est rerum tempore vitae
sequi sint nihil reprehenderit dolor beatae ea dolores neque
fugiat blanditiis voluptate porro vel nihil molestiae ut reiciendis
qui aperiam non debitis possimus qui neque nisi nulla" }]
{
  "id": 101
}
{
  "id": 1
}
{}