zwvista

JSON : Placeholder

JSON : Placeholder (https://jsonplaceholder.typicode.com/) 是一個用于測試的 REST API 網站。
以下使用 RxJS6 + React.js 調用該網站的 REST API，獲取字符串以及 JSON 數據。

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

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

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

創建工程

# 安裝 CLI
$ npm install -g cra-template-typescript
# 創建新的應用程序 FetchExample
$ npx create-react-app fetch-example --template typescript
$ cd fetch-example
$ npm start

打開 Intellij IDEA, File / Open...，然后選中工程所在文件夾

點擊 Add Configurations, 點擊 +npm
Name: React CLI Server
Scripts: start
點擊 OK 完成配置。
點擊 React CLI Server 啟動程序。
http://localhost:3000/ 可打開網頁。

Post

在 src 文件夾下添加 post.ts，內容如下

export class Post {
  userId!: number;
  id!: number;
  title!: string;
  body!: string;
  toString(): string {
    return `Post {userId = ${this.userId}, id = ${this.id}, title = "${this.title}", body = "${this.body.replace(/\n/g, '\\n')}"}`;
  }
}

post 服務

在 src 文件夾下添加 post.service.ts，內容如下

import { Post } from './post';

export class PostService {
  private readonly baseUrl = 'https://jsonplaceholder.typicode.com/';

  constructor() {
    this.getPostAsString();
    this.getPostAsJson();
    this.getPosts(2);
    this.createPost();
    this.updatePost();
    this.deletePost();
  }

  private async getPostAsString() {
    const url = `${this.baseUrl}posts/1`;
    const result = await fetch(url);
    const data = await result.text();
    console.log(data);
  }

  private async getPostAsJson() {
    const url = `${this.baseUrl}posts/1`;
    const result = await fetch(url);
    const data = await result.json();
    const post = Object.assign(new Post(), data);
    console.log(post);
  }

  private async getPosts(n: number) {
    const url = `${this.baseUrl}posts`;
    const result = await fetch(url);
    const data = await result.json();
    (data as Post[]).slice(0, n).map(v => {
      const post = Object.assign(new Post(), v);
      console.log(post);
      return post;
    });
  }

  private async createPost() {
    const url = `${this.baseUrl}posts`;
    const result = await fetch(url, {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({
        userId: 101,
        title: 'test title',
        body: 'test body',
      })
    });
    const data = await result.json();
    const post = Object.assign(new Post(), data);
    console.log(post);
  }

  private async updatePost() {
    const url = `${this.baseUrl}posts/1`;
    const result = await fetch(url, {
      method: 'PUT',
      headers: {
        'Content-Type': 'application/json'
      },
      body: JSON.stringify({
        userId: 101,
        title: 'test title',
        body: 'test body',
      })
    });
    const data = await result.json();
    const post = Object.assign(new Post(), data);
    console.log(post);
  }

  private async deletePost() {
    const url = `${this.baseUrl}posts/1`;
    const result = await fetch(url, {
      method: 'DELETE'
    });
    const data = await result.text();
    console.log(data);
  }
}

• getPostAsString 方法取出第1個Post，返回字符串
• getPostAsJson 方法取出第1個Post，返回Post對象
• getPosts 方法取出前n個Post，返回n個Post對象
• createPost 方法創建1個Post，返回字符串
• updatePost 方法更新第1個Post，返回字符串
• deletePost 方法刪除第1個Post，返回字符串

打開 App.tsx，將其改為

import * as React from 'react';
import './App.css';

import logo from './logo.svg';
import { PostService } from './post.service';

class App extends React.Component {
  postService!: PostService;

  componentDidMount() {
    this.postService = new PostService();
  }

  public render() {
    return (
      <div className="App">
        <header className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <h1 className="App-title">Welcome to React</h1>
        </header>
        <p className="App-intro">
          To get started, edit <code>src/App.tsx</code> and save to reload.
        </p>
      </div>
    );
  }
}
 
export default App;

輸出結果

{
  "userId": 1,
  "id": 1,
  "title": "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
  "body": "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"
}
Post {userId = 1, id = 1, title = "sunt aut facere repellat provident occaecati excepturi optio reprehenderit", body = "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"}
Post {userId = 1, id = 1, title = "sunt aut facere repellat provident occaecati excepturi optio reprehenderit", body = "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"}
Post {userId = 1, id = 2, title = "qui est esse", body = "est rerum tempore vitae\nsequi sint nihil reprehenderit dolor beatae ea dolores neque\nfugiat blanditiis voluptate porro vel nihil molestiae ut reiciendis\nqui aperiam non debitis possimus qui neque nisi nulla"}
{"params":{"userId":101,"title":"test title","body":"test body"},"id":101}
{"params":{"userId":101,"title":"test title","body":"test body"},"id":1}
{}