nodejs常用模块介绍

常用URL内置方法

url.parse();
url.format()
url.resolve()

querystring

image.png

http/https小爬虫功能

var http = require('http');
var https = require('https');
var cheerio = require('cheerio') // 同jQuery插件
var url = 'url' // 要爬的网络地址
function filterMenu(html) {
    var $ = cheerio.load(html)
    var menu = $('.product-nav')
    var menuData = []
    menu.each(function(index, dom) {
        var menuTitle = $(dom).find('li').text();
        var menuLists = $(dom).find('a');
        var menuList = []
        // menuList.each(function(index, value) {
        //     menuList.push()
        // })
        menuData.push({
            menTitle: menuTitle,
            menuList: menuLists
        })
    })
    return menuData
}
function printMenu(menu) {
    menu.forEach(function (value) {
        console.log(value.menTitle + '\n')
    });
}
http.get(url, function(res) {
    var html = '';
    res.on('data', function(data) {
        html += data;
    });
    res.on('end', function() {
        // console.log(html)
        var result = filterMenu(html);
        printMenu(result);
    })
    res.on('error', function(err) {
        console.log(err)
    })
})

request GET功能

const https = require('https');

var options = {
    hostname: 'spark.appublisher.com',
    port: 443,
    mrthod: 'GET',
    path: '/course/get_open_class'
}
var responseData = '';
var request = https.request(options, (response) => {
    // console.log(response);
    // console.log(response.statusCode);
    // console.log(response.headers);

    response.setEncoding('utf8');
    response.on('data', (chunk) => {
        responseData += chunk;
    })
    response.on('end', () => {
        JSON.parse(responseData).courses.map((item) => {
            console.log(item.name)
        })
    })
})
request.on('error', (error) => {
    console.log(error);
})
request.end();

request POST功能

const https = require('https');
const querystring = require('querystring')

var postData = querystring.stringify({
    
})
var options = {
    hostname: 'spark.appublisher.com',
    port: 443,
    mrthod: 'POST',
    path: '/course/get_open_class',
    headers: {

    }
}
var responseData = '';
var request = https.request(options, (res) => {
    // console.log(response);
    // console.log(response.statusCode);
    // console.log(response.headers);

    response.setEncoding('utf8');
    response.on('data', (chunk) => {
        responseData += chunk;
    })
    response.on('end', () => {
        console.log('提交成功')
    })
})
request.on('error', (error) => {
    console.log(error);
})
request.write(postData)
request.end();

event事件功能

const EventEmitter = require('events');

class Player extends EventEmitter {}

var player = new Player()

player.on('play', (track) => {
    console.log(`正在播放《${track}》`)
})
player.emit('play', '黑凤凰')
player.emit('play', '复仇者联盟4')