爬虫黑科技，我是怎么爬取 indeed 的职位数据的

最近在学习 ndejs 爬虫技术，学了 request 模块，所以想着写一个自己的爬虫项目，研究了半天，最后选定 indeed 作为目标网站，通过爬取 indeed 的职位数据，然后开发一个自己的职位搜索引擎，目前已经上线了，虽然功能还是比较简单，但还是贴一下网址job search engine，证明一下这个爬虫项目是有用的。下面就来讲讲整个爬虫的思路。

确定入口页面

众所周知，爬虫是需要入口页面的，通过入口页面，不断的爬取链接，最后爬取完整个网站。在这个第一步的时候，就遇到了困难，一般来说都是选取首页和列表页作为入口页面的，但是 indeed 的列表页面做了限制，不能爬取完整的列表，顶多只能抓取前 100 页，但是这没有难倒我，我发现 indeed 有一个Browse Jobs 页面，通过这个页面，可以获取 indeed 按地区搜索和按类型搜索的所有列表。下面贴一下这个页面的解析代码。

start: async (page) => { const host = URL.parse(page.url).hostname; const tasks = []; try { const $ = cheerio.load(iconv.decode(page.con, 'utf-8'), { decodeEntities: false }); $('#states > tbody > tr > td > a').each((i, ele) => { const url = URL.resolve(page.url, $(ele).attr('href')); tasks.push({ _id: md5(url), type: 'city', host, url, done: 0, name: $(ele).text() }); }); $('#categories > tbody > tr > td > a').each((i, ele) => { const url = URL.resolve(page.url, $(ele).attr('href')); tasks.push({ _id: md5(url), type: 'category', host, url, done: 0, name: $(ele).text() }); }); const res = await global.com.task.insertMany(tasks, { ordered: false }).catch(() => {}); res && console.log(`${host}-start insert ${res.insertedCount} from ${tasks.length} tasks`); return 1; } catch (err) { console.error(`${host}-start parse ${page.url} ${err}`); return 0; } } 

通过 cheerio 解析 html 内容，把按地区搜索和按类型搜索链接插入到数据库中。

爬虫架构

这里简单讲一下我的爬虫架构思路，数据库选用 mongodb。每一个待爬取的页面存一条记录 page，包含 id,url,done,type,host 等字段，id 用md5(url)生成，避免重复。每一个 type 有一个对应的 html 内容解析方法，主要的业务逻辑都集中在这些解析方法里面，上面贴出来的代码就是例子。

爬取 html 采用 request 模块，进行了简单的封装，把 callback 封装成 promise，方便使用 async 和 await 方式调用，代码如下。

const req = require('request'); const request = req.defaults({ headers: { 'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36' }, timeout: 30000, encoding: null }); const fetch = (url) => new Promise((resolve) => { console.log(`down ${url} started`); request(encodeURI(url), (err, res, body) => { if (res && res.statusCode === 200) { console.log(`down ${url} 200`); resolve(body); } else { console.error(`down ${url} ${res && res.statusCode} ${err}`); if (res && res.statusCode) { resolve(res.statusCode); } else { // ESOCKETTIMEOUT 超时错误返回 600 resolve(600); } } }); }); 

做了简单的反反爬处理，把 user-agent 改成电脑通用的 user-agent，设置了超时时间 30 秒，其中encoding: null设置 request 直接返回 buffer，而不是解析后的内容，这样的好处是如果页面是 gbk 或者 utf-8 编码，只要解析 html 的时候指定编码就行了，如果这里指定encoding: utf-8，则当页面编码是 gbk 的时候，页面内容会乱码。

request 默认是回调函数形式，通过 promise 封装，如果成功，则返回页面内容的 buffer，如果失败，则返回错误状态码，如果超时，则返回 600，这些懂 nodejs 的应该很好理解。

完整的解析代码

const URL = require('url'); const md5 = require('md5'); const cheerio = require('cheerio'); const icOnv= require('iconv-lite'); const json = (data) => { let res; try { res = JSON.parse(data); } catch (err) { console.error(err); } return res; }; const rules = [ /\/jobs\?q=.*&sort=date&start=\d+/, /\/jobs\?q=&l=.*&sort=date&start=\d+/ ]; const fns = { start: async (page) => { const host = URL.parse(page.url).hostname; const tasks = []; try { const $ = cheerio.load(iconv.decode(page.con, 'utf-8'), { decodeEntities: false }); $('#states > tbody > tr > td > a').each((i, ele) => { const url = URL.resolve(page.url, $(ele).attr('href')); tasks.push({ _id: md5(url), type: 'city', host, url, done: 0, name: $(ele).text() }); }); $('#categories > tbody > tr > td > a').each((i, ele) => { const url = URL.resolve(page.url, $(ele).attr('href')); tasks.push({ _id: md5(url), type: 'category', host, url, done: 0, name: $(ele).text() }); }); const res = await global.com.task.insertMany(tasks, { ordered: false }).catch(() => {}); res && console.log(`${host}-start insert ${res.insertedCount} from ${tasks.length} tasks`); return 1; } catch (err) { console.error(`${host}-start parse ${page.url} ${err}`); return 0; } }, city: async (page) => { const host = URL.parse(page.url).hostname; const tasks = []; const cities = []; try { const $ = cheerio.load(iconv.decode(page.con, 'utf-8'), { decodeEntities: false }); $('#cities > tbody > tr > td > p.city > a').each((i, ele) => { // https://www.indeed.com/l-Charlotte,-NC-jobs.html let tmp = $(ele).attr('href').match(/l-(?<loc>.*)-jobs.html/u); if (!tmp) { tmp = $(ele).attr('href').match(/l=(?<loc>.*)/u); } const { loc } = tmp.groups; const url = `https://www.indeed.com/jobs?l=${decodeURIComponent(loc)}&sort=date`; tasks.push({ _id: md5(url), type: 'search', host, url, done: 0 }); cities.push({ _id: `${$(ele).text()}_${page.name}`, parent: page.name, name: $(ele).text(), url }); }); let res = await global.com.city.insertMany(cities, { ordered: false }).catch(() => {}); res && console.log(`${host}-city insert ${res.insertedCount} from ${cities.length} cities`); res = await global.com.task.insertMany(tasks, { ordered: false }).catch(() => {}); res && console.log(`${host}-city insert ${res.insertedCount} from ${tasks.length} tasks`); return 1; } catch (err) { console.error(`${host}-city parse ${page.url} ${err}`); return 0; } }, category: async (page) => { const host = URL.parse(page.url).hostname; const tasks = []; const categories = []; try { const $ = cheerio.load(iconv.decode(page.con, 'utf-8'), { decodeEntities: false }); $('#titles > tbody > tr > td > p.job > a').each((i, ele) => { const { query } = $(ele).attr('href').match(/q-(?<query>.*)-jobs.html/u).groups; const url = `https://www.indeed.com/jobs?q=${decodeURIComponent(query)}&sort=date`; tasks.push({ _id: md5(url), type: 'search', host, url, done: 0 }); categories.push({ _id: `${$(ele).text()}_${page.name}`, parent: page.name, name: $(ele).text(), url }); }); let res = await global.com.category.insertMany(categories, { ordered: false }).catch(() => {}); res && console.log(`${host}-category insert ${res.insertedCount} from ${categories.length} categories`); res = await global.com.task.insertMany(tasks, { ordered: false }).catch(() => {}); res && console.log(`${host}-category insert ${res.insertedCount} from ${tasks.length} tasks`); return 1; } catch (err) { console.error(`${host}-category parse ${page.url} ${err}`); return 0; } }, search: async (page) => { const host = URL.parse(page.url).hostname; const tasks = []; const durls = []; try { const con = iconv.decode(page.con, 'utf-8'); const $ = cheerio.load(con, { decodeEntities: false }); const list = con.match(/jobmap\[\d+\]= {.*}/g); const jobmap = []; if (list) { // eslint-disable-next-line no-eval list.map((item) => eval(item)); } for (const item of jobmap) { const cmplink = URL.resolve(page.url, item.cmplnk); const { query } = URL.parse(cmplink, true); let name; if (query.q) { // eslint-disable-next-line prefer-destructuring name = query.q.split(' #')[0].split('#')[0]; } else { const tmp = cmplink.match(/q-(?<text>.*)-jobs.html/u); if (!tmp) { // eslint-disable-next-line no-continue continue; } const { text } = tmp.groups; // eslint-disable-next-line prefer-destructuring name = text.replace(/-/g, ' ').split(' #')[0]; } const surl = `https://www.indeed.com/cmp/_cs/cmpauto?q=${name}&n=10&returnlogourls=1&returncmppageurls=1&caret=8`; const burl = `https://www.indeed.com/viewjob?jk=${item.jk}&from=vjs&vjs=1`; const durl = `https://www.indeed.com/rpc/jobdescs?jks=${item.jk}`; tasks.push({ _id: md5(surl), type: 'suggest', host, url: surl, done: 0 }); tasks.push({ _id: md5(burl), type: 'brief', host, url: burl, done: 0 }); durls.push({ _id: md5(durl), type: 'detail', host, url: durl, done: 0 }); } $('a[href]').each((i, ele) => { const tmp = URL.resolve(page.url, $(ele).attr('href')); const [url] = tmp.split('#'); const { path, hostname } = URL.parse(url); for (const rule of rules) { if (rule.test(path)) { if (hostname == host) { // tasks.push({ _id: md5(url), type: 'list', host, url: decodeURI(url), done: 0 }); } break; } } }); let res = await global.com.task.insertMany(tasks, { ordered: false }).catch(() => {}); res && console.log(`${host}-search insert ${res.insertedCount} from ${tasks.length} tasks`); res = await global.com.task.insertMany(durls, { ordered: false }).catch(() => {}); res && console.log(`${host}-search insert ${res.insertedCount} from ${durls.length} tasks`); return 1; } catch (err) { console.error(`${host}-search parse ${page.url} ${err}`); return 0; } }, suggest: async (page) => { const host = URL.parse(page.url).hostname; const tasks = []; const companies = []; try { const con = page.con.toString('utf-8'); const data = json(con); for (const item of data) { const id = item.overviewUrl.replace('/cmp/', ''); const cmpurl = `https://www.indeed.com/cmp/${id}`; const joburl = `https://www.indeed.com/cmp/${id}/jobs?clearPrefilter=1`; tasks.push({ _id: md5(cmpurl), type: 'company', host, url: cmpurl, done: 0 }); tasks.push({ _id: md5(joburl), type: 'jobs', host, url: joburl, done: 0 }); companies.push({ _id: id, name: item.name, url: cmpurl }); } let res = await global.com.company.insertMany(companies, { ordered: false }).catch(() => {}); res && console.log(`${host}-suggest insert ${res.insertedCount} from ${companies.length} companies`); res = await global.com.task.insertMany(tasks, { ordered: false }).catch(() => {}); res && console.log(`${host}-suggest insert ${res.insertedCount} from ${tasks.length} tasks`); return 1; } catch (err) { console.error(`${host}-suggest parse ${page.url} ${err}`); return 0; } }, // list: () => {}, jobs: async (page) => { const host = URL.parse(page.url).hostname; const tasks = []; const durls = []; try { const con = iconv.decode(page.con, 'utf-8'); const tmp = con.match(/window._initialData=(?<text>.*);<\/script><script>window._sentryData/u); let data; if (tmp) { const { text } = tmp.groups; data = json(text); if (data.jobList && data.jobList.pagination && data.jobList.pagination.paginationLinks) { for (const item of data.jobList.pagination.paginationLinks) { // eslint-disable-next-line max-depth if (item.href) { item.href = item.href.replace(/\u002F/g, '/'); const url = URL.resolve(page.url, decodeURI(item.href)); tasks.push({ _id: md5(url), type: 'jobs', host, url: decodeURI(url), done: 0 }); } } } if (data.jobList && data.jobList.jobs) { for (const job of data.jobList.jobs) { const burl = `https://www.indeed.com/viewjob?jk=${job.jobKey}&from=vjs&vjs=1`; const durl = `https://www.indeed.com/rpc/jobdescs?jks=${job.jobKey}`; tasks.push({ _id: md5(burl), type: 'brief', host, url: burl, done: 0 }); durls.push({ _id: md5(durl), type: 'detail', host, url: durl, done: 0 }); } } } else { console.log(`${host}-jobs ${page.url} has no _initialData`); } let res = await global.com.task.insertMany(tasks, { ordered: false }).catch(() => {}); res && console.log(`${host}-search insert ${res.insertedCount} from ${tasks.length} tasks`); res = await global.com.task.insertMany(durls, { ordered: false }).catch(() => {}); res && console.log(`${host}-search insert ${res.insertedCount} from ${durls.length} tasks`); return 1; } catch (err) { console.error(`${host}-jobs parse ${page.url} ${err}`); return 0; } }, brief: async (page) => { const host = URL.parse(page.url).hostname; try { const con = page.con.toString('utf-8'); const data = json(con); data.dOne= 0; data.views = 0; data.host = host; // format publish date if (data.vfvm && data.vfvm.jobAgeRelative) { const str = data.vfvm.jobAgeRelative; const tmp = str.split(' '); const [first, second] = tmp; if (first == 'Just' || first == 'Today') { data.publishDate = Date.now(); } else { const num = first.replace(/\+/, ''); if (secOnd== 'hours') { const date = new Date(); const time = date.getTime(); // eslint-disable-next-line no-mixed-operators date.setTime(time - num * 60 * 60 * 1000); data.publishDate = date.getTime(); } else if (secOnd== 'days') { const date = new Date(); const time = date.getTime(); // eslint-disable-next-line no-mixed-operators date.setTime(time - num * 24 * 60 * 60 * 1000); data.publishDate = date.getTime(); } else { data.publishDate = Date.now(); } } } await global.com.job.updateOne({ _id: data.jobKey }, { $set: data }, { upsert: true }).catch(() => { }); const tasks = []; const url = `https://www.indeed.com/jobs?l=${data.jobLocationModel.jobLocation}&sort=date`; tasks.push({ _id: md5(url), type: 'search', host, url, done: 0 }); const res = await global.com.task.insertMany(tasks, { ordered: false }).catch(() => {}); res && console.log(`${host}-brief insert ${res.insertedCount} from ${tasks.length} tasks`); return 1; } catch (err) { console.error(`${host}-brief parse ${page.url} ${err}`); return 0; } }, detail: async (page) => { const host = URL.parse(page.url).hostname; try { const con = page.con.toString('utf-8'); const data = json(con); const [jobKey] = Object.keys(data); await global.com.job.updateOne({ _id: jobKey }, { $set: { content: data[jobKey], done: 1 } }).catch(() => { }); return 1; } catch (err) { console.error(`${host}-detail parse ${page.url} ${err}`); return 0; } }, run: (page) => { if (page.type == 'list') { page.type = 'search'; } const fn = fns[page.type]; if (fn) { return fn(page); } console.error(`${page.url} parser not found`); return 0; } }; module.exports = fns; 

每一个解析方法都会插入一些新的链接，新的链接记录都会有一个 type 字段，通过 type 字段，可以知道新的链接的解析方法，这样就能完整解析所有的页面了。例如 start 方法会插入 type 为 city 和 category 的记录，type 为 city 的页面记录的解析方法就是city方法，city 方法里面又会插入 type 为 search 的链接，这样一直循环，直到最后的 brief 和 detail 方法分别获取职位数据的简介和详细内容。

其实爬虫最关键的就是这些 html 解析方法，有了这些方法，你就能获取任何想要的结构化内容了。

数据索引

这部分就很简单了，有了前面获取的结构化数据，按照 elasticsearch，新建一个 schema，然后写个程序定时把职位数据添加到 es 的索引里面就行了。因为职位详情的内容有点多，我就没有把 content 字段添加到索引里面了，因为太占内存了，服务器内存不够用了，>_<。

DEMO

最后还是贴上网址供大家检阅，job search engine。