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116 lines
4.2 KiB
116 lines
4.2 KiB
6 months ago
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/**
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* 普通网站用爬虫
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* 抓取规则:
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* 1. 解析<title></title>标签
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* 2. 解析<meta>标签里的分享图片属性,任何property里包含og:image的标签属性content,参考:https://ogp.me/
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* 3. 如果上述步骤都没有解析道图片,则从<body></body>中解析所有的<img>标签,默认抓取第一张图片,并尝试抓取加载完成的图片宽度>=300px的
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*/
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import Hero from '@ulixee/hero';
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import HeroBot from './HeroBot.mjs';
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import ClientLogPlugin from '../plugin/ClientLogPlugin.mjs';
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import common from '../lib/common.mjs';
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class WebCrawler extends HeroBot {
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async scrap(url) {
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let data = {url: url, done: false};
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//use iphone
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if (this.ua == 'mob') {
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configs.userAgent = configs.userAgents.iphone_safari;
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configs.viewport = configs.viewports.mob;
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}
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let options = {
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userAgent: configs.userAgent, //default mac os
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viewport: configs.viewport,
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};
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options = common.mergeConfigs(configs.botOptions, options);
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if (this.heroServer) {
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options.connectionToCore = this.heroServer;
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}
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const hero = new Hero(options);
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try {
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hero.use(ClientLogPlugin); //开启log
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await hero.goto(url, configs.heroBotOptions);
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//等待所有内容加载完成
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const tab = await hero.activeTab;
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await tab.waitForLoad('DomContentLoaded', {timeoutMs: configs.heroTabOptions.timeoutMs});
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//解析网页HTML数据
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data.title = await hero.document.title;
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//封面图抓取
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//1. 解析meta
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const elems = await hero.document.querySelectorAll('meta');
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let meta_name = '';
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for (const elem of elems) {
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meta_name = await elem.getAttribute('property');
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if (!meta_name) {continue;}
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meta_name = meta_name.toLowerCase();
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if (!data.cover && meta_name.indexOf('og:image') > -1) {
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data.cover = await elem.getAttribute('content');
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}else if (!data.cover && meta_name.indexOf('image') > -1) {
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let contentStr = await elem.getAttribute('content');
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if (common.isUrl(contentStr)) {
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data.cover = contentStr;
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}
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}else if (meta_name.indexOf('og:title') > -1) {
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data.title = await elem.getAttribute('content');
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}
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}
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//2. <img>解析
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if (!data.cover) {
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let minNaturalWidth = configs.minImageNaturalWidth ? configs.minImageNaturalWidth : 50;
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const imgElems = await hero.querySelectorAll('img');
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if (imgElems) {
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data.cover = await imgElems[0].src;
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for (const imgEl of imgElems) {
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//console.log('Completed: %s, naturalWidth: %s, width: %s', await imgEl.complete, await imgEl.naturalWidth, await imgEl.width);
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if (await imgEl.complete && await imgEl.naturalWidth >= minNaturalWidth) {
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data.cover = await imgEl.src;
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//console.log('Cover got: %s', data.cover);
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break;
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}
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}
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}
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}
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//get cover image's base64 data
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if (typeof(data.cover) != 'undefined' && data.cover) {
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data.cover = common.getAbsoluteUrl(data.cover);
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const response = await hero.goto(data.cover);
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const imgBuffer = await response.buffer;
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//console.log('Cover image fetch done', imgBuffer.toString('base64'));
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if (imgBuffer) {
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data.cover_base64 = imgBuffer.toString('base64');
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data.cover_type = common.getImageType(data.cover);
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}
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}
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await hero.close();
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data.bot = this.name;
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data.done = true;
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}catch(error) {
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console.error("Error got when request %s via hero: %s", url, error);
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await hero.close();
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}
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return data;
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}
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}
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export default WebCrawler;
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