JSON : Placeholder

JSON : Placeholder (https://jsonplaceholder.typicode.com/) 是一个用于测试的 REST API 网站。

以下使用 RxJS6 + Vue.js 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"}

  }

}

创建工程

# 安装 Vue CLI

$ npm install --global @vue/cli

# 创建新的应用程序 RxExample

$ vue create rx-example

# 选择 Manually select features

# 选择 Babel 和 TypeScript

$ cd rx-example

$ npm run serve

打开 Intellij IDEA, File / New / Project From Existing Sources...，然后选中工程所在文件夹

在向导的第1页选择 Create project from existing sources

完成向导后在点击 Finish 创建工程。

点击 Add Configurations, 点击 +npm

Name: Vue CLI Server

Scripts: serve

点击 OK 完成配置。

点击 Vue CLI Server 启动程序。

http://localhost:8080/ 可打开网页。

Post

在 src 文件夹下添加 post.ts，内容如下

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')}"}`;

  }

}

安装 vue-typescript-inject

vue-typescript-inject 是一个在 Vue.js 中实现 DI（依赖注入） 的包。

使用这个包需要安装 vue-typescript-inject 和 reflect-metadata。

$ npm i vue-typescript-inject reflect-metadata

打开 tsconfig.json 在 compilerOptions 中

添加关于 emitDecoratorMetadata 的设定。

    "emitDecoratorMetadata": true,

    "experimentalDecorators": true,

打开 main.ts 将其改为

import 'reflect-metadata';

import Vue from 'vue'

import App from './App.vue'

import VueTypeScriptInject from 'vue-typescript-inject';

Vue.config.productionTip = false;

Vue.use(VueTypeScriptInject); // register vue-typescript-inject

new Vue({

  render: h => h(App),

}).$mount('#app');

安装 Rxios

访问 API 采用将 RxJS 和 axios 合为一体的 Rxios 组件，但是该组件尚未升级到 RxJS6。

这里我们只安装 RxJS 和 axios，然后直接以源码形式引入 Rxios，并将其升级到 RxJS6。

$ npm install axios rxjs

在 src 文件夹下添加 rxios.ts，内容如下

// https://github.com/davguij/rxios/blob/master/src/index.ts

// ported to rxjs6

import axios, { AxiosInstance, AxiosRequestConfig, AxiosPromise } from 'axios';

// import { Observable } from 'rxjs/Observable';

import { Observable } from 'rxjs';

export interface rxiosConfig extends AxiosRequestConfig {

  localCache?: boolean;

}

class rxios {

  private _httpClient: AxiosInstance;

  constructor(options: rxiosConfig = {}) {

    this._httpClient = axios.create(options);

  }

  private _makeRequest<T>(method: string, url: string, queryParams?: object, body?: object) {

    let request: AxiosPromise<T>;

    switch (method) {

      case 'GET':

        request = this._httpClient.get<T>(url, {params: queryParams});

        break;

      case 'POST':

        request = this._httpClient.post<T>(url, body, {params: queryParams});

        break;

      case 'PUT':

        request = this._httpClient.put<T>(url, body, {params: queryParams});

        break;

      case 'PATCH':

        request = this._httpClient.patch<T>(url, body, {params: queryParams});

        break;

      case 'DELETE':

        request = this._httpClient.delete(url, {params: queryParams});

        break;

      default:

        throw new Error('Method not supported');

    }

    return new Observable<T>(subscriber => {

      request.then(response => {

        subscriber.next(response.data);

        subscriber.complete();

      }).catch((err: Error) => {

        subscriber.error(err);

        subscriber.complete();

      });

    });

  }

  public get<T>(url: string, queryParams?: object) {

    return this._makeRequest<T>('GET', url, queryParams);

  }

  public post<T>(url: string, body: object, queryParams?: object) {

    return this._makeRequest<T>('POST', url, queryParams, body);

  }

  public put<T>(url: string, body: object, queryParams?: object) {

    return this._makeRequest<T>('PUT', url, queryParams, body);

  }

  public patch<T>(url: string, body: object, queryParams?: object) {

    return this._makeRequest<T>('PATCH', url, queryParams, body);

  }

  public delete(url: string, queryParams?: object) {

    return this._makeRequest('DELETE', url, queryParams);

  }

}

export {rxios, rxios as Rxios};

post 服务

在 src 文件夹下添加 post.service.ts，内容如下

import { Injectable } from 'react.di';

import { Observable, from } from 'rxjs';

import { map, mergeAll, take, tap } from 'rxjs/operators';

import { Post } from './post';

import { Rxios } from './rxios';

@Injectable

export class PostService {

  private readonly http = new Rxios();

  private readonly baseUrl = 'http://jsonplaceholder.typicode.com/';

  constructor() {

    this.getPostAsString().subscribe();

    this.getPostAsJson().subscribe();

    this.getPosts(2).subscribe();

    this.createPost().subscribe();

    this.updatePost().subscribe();

    this.deletePost().subscribe();

  }

  private getPostAsString(): Observable<string> {

    const url = `${this.baseUrl}posts/1`;

    return new Rxios({transformResponse: undefined}).get<string>(url)

      .pipe(

        tap((result: any) => console.log(result)),

      );

  }

  private getPostAsJson(): Observable<Post> {

    const url = `${this.baseUrl}posts/1`;

    return this.http.get<Post>(url)

      .pipe(

        map((result: any) => Object.assign(new Post(), result)),

        tap((result: any) => console.log('' + result)),

      );

  }

  private getPosts(n: number): Observable<Post> {

    const url = `${this.baseUrl}posts`;

    return from(this.http.get<Post[]>(url))

      .pipe(

        mergeAll(),

        map((result: any) => Object.assign(new Post(), result)),

        take(n),

        tap((result: any) => console.log('' + result)),

      );

  }

  private createPost(): Observable<string> {

    const url = `${this.baseUrl}posts`;

    return this.http.post(url, {

      params: {

        userId: 101,

        title: 'test title',

        body: 'test body',

      }

    })

      .pipe(

        map((result: any) => JSON.stringify(result)),

        tap((result: any) => console.log(result)),

      );

  }

  private updatePost(): Observable<string> {

    const url = `${this.baseUrl}posts/1`;

    return this.http.put(url, {

      params: {

        userId: 101,

        title: 'test title',

        body: 'test body',

      }

    })

      .pipe(

        map((result: any) => JSON.stringify(result)),

        tap((result: any) => console.log(result)),

      );

  }

  private deletePost(): Observable<string> {

    const url = `${this.baseUrl}posts/1`;

    return this.http.delete(url)

      .pipe(

        map((result: any) => JSON.stringify(result)),

        tap((result: any) => console.log(result)),

      );

  }

}

• getPostAsString 方法取出第1个Post，返回字符串
• getPostAsJson 方法取出第1个Post，返回Post对象
• getPosts 方法取出前n个Post，返回n个Post对象
• createPost 方法创建1个Post，返回字符串
• updatePost 方法更新第1个Post，返回字符串
• deletePost 方法删除第1个Post，返回字符串

删除 HelloWorld 组件，即 src/components/HelloWorld.vue 文件。

打开 App.vue，将其改为

<template>

</template>

<script lang="ts">

import { Component, Vue } from 'vue-property-decorator';

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

import { inject } from 'vue-typescript-inject';

@Component({

  providers: [

    PostService,

  ],

})

export default class App extends Vue {

  @inject() postService!: PostService;

}

</script>

<style>

</style>

输出结果

{

  "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 = 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"}

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"}

{"params":{"userId":101,"title":"test title","body":"test body"},"id":101}

{"params":{"userId":101,"title":"test title","body":"test body"},"id":1}

{}