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115 lines
4.2 KiB
115 lines
4.2 KiB
/** |
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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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