ts--demo(网页内容抓取)

1.新建项目
①npm init -y 生成package.json
②tsc --init 生成 tsconfig.json
③安装tsc -node npm i tsc-node -D(安装在开发环境)
④package.json 配置scripts,安装typescript (npm i typescript -D)

---

爬取网页内容与数据
①

/*
 * @Author: itw_liuchao04 [email protected]
 * @Date: 2022-10-21 15:07:19
 * @LastEditors: itw_liuchao04 [email protected]
 * @LastEditTime: 2022-10-22 15:13:06
 * @FilePath: \TypeScript\src\crowller.ts
 * @Description:
 *
 * Copyright (c) 2022 by itw_liuchao04 [email protected], All Rights Reserved.
 */
import fs from "fs";
import path from "path";
//ts ->.d.ts 翻译文件 @type/superagent -->js
import superagent from "superagent";
import DellAnalyzer from "./analizer";

export interface Analyzer {
  anylaze: (html: string, filePath: string) => string;
}

class Crowller {
  private filePath = path.resolve(__dirname, "../data/course.json");
  private async getRawHtml() {
    let result = await superagent.get(this.url);
    return result.text;
  }

  private writeFile(fileContent: string) {
    fs.writeFileSync(this.filePath, fileContent);
  }
  private async initSpliderProcess() {
    const html = await this.getRawHtml();

    const file = this.analyzer.anylaze(html, this.filePath);
    this.writeFile(file);
  }
  constructor(private url: string, private analyzer: Analyzer) {
    this.initSpliderProcess();
  }
}

const secret = "secretKey";
const url = `http://www.dell-lee.com/typescript/demo.html?secret=${secret}`;
//获取分析实例
// const analyzer = new DellAnalyzer();
//获取唯一实例
const analyzer = DellAnalyzer.getInstance();

//创建爬虫实例
let crowller = new Crowller(url, analyzer);

②

//创建课程约束
interface Course {
  title: string;
  count: number;
}

//创建整合课程数据的约束
interface CourseContent {
  time: number;
  data: Course[];
}
interface CourseList {
  [propsName: number]: Course[];
}
import fs from "fs";
//获取各区块内容
import cheerio from "cheerio";
import { Analyzer } from "./crowller";
//用来处理数据
export default class DellAnalyzer implements Analyzer {
  private static instance: DellAnalyzer;
  private constructor() {}
  static getInstance() {
    if (!DellAnalyzer.instance) {
      DellAnalyzer.instance = new DellAnalyzer();
    }
    return DellAnalyzer.instance;
  }
  private getCourses(html: string) {
    let $ = cheerio.load(html);
    let courses = $(".course-item");
    console.log(courses.length);
    let courseList: Course[] = [];
    courses.map((index, el) => {
      let title = $(el).find(".course-desc").eq(0).text();
      let count = parseInt(
        $(el).find(".course-desc").eq(1).text().split("：")[1],
        10
      );
      courseList.push({ title, count });
    });

    const result = {
      time: new Date().getTime(),
      data: courseList,
    };
    return result;
  }
  private generateJsonContent(filePath: string, courseList: CourseContent) {
    //获取存储路径

    let fileContent: CourseList = {};
    if (fs.existsSync(filePath)) {
      //如果已经写过
      fileContent = JSON.parse(fs.readFileSync(filePath, "utf-8"));
    }
    fileContent[courseList.time] = courseList.data;
    return fileContent;
  }
  anylaze(html: string, filePath: string) {
    const courses = this.getCourses(html);
    return JSON.stringify(this.generateJsonContent(filePath, courses));
  }
}

获取到的网页内容.png

通过tsc -w 命令，使得tsc监视文件变化从而实现实时编译

//package.json中
"scripts": {
    "dev": "ts-node ./src/crowller.ts",
    "build": "tsc -w"
  },

nodemon :监听js变化,立即执行;

"scripts": {
    "dev": "ts-node ./src/crowller.ts",
    "build": "tsc -w",
    "start": "nodemon node ./build/crowller.js"
  },
//设置忽略
 "nodemonConfig": {
    "ignore": [
      "data/*"
    ]
  },

打开两个命令行,先执行build,另一个命令行start,即可同时监听ts文件变化并执行.
上面的执行太过麻烦,我们可以再对其进行优化

//dev环境下,帮我们同时运行 build,start
"scripts": {
    "dev:build": "tsc -w",
    "dev:start": "nodemon node ./build/crowller.js",
    "dev": "concurrently npm:dev:*"
  },