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Distributed crawler powered by Headless Chrome
Crawlers based on simple requests to HTML files are generally fast. However, it sometimes ends up capturing empty bodies, especially when the websites are built on such modern frontend frameworks as AngularJS, React and Vue.js.
Powered by Headless Chrome, the crawler provides simple APIs to crawl these dynamic websites with the following features:
- Distributed crawling
- Configure concurrency, delay and retry
- Support both depth-first search and breadth-first search algorithm
- Pluggable cache storages such as Redis
- Support CSV and JSON Lines for exporting results
- Pause at the max request and resume at any time
- Insert jQuery automatically for scraping
- Save screenshots for the crawling evidence
- Emulate devices and user agents
- Priority queue for crawling efficiency
- Obey robots.txt
- Follow sitemap.xml
- [Promise] support
yarn add headless-chrome-crawler
# or "npm i headless-chrome-crawler"Note: headless-chrome-crawler contains Puppeteer. During installation, it automatically downloads a recent version of Chromium. To skip the download, see Environment variables.
const HCCrawler = require('headless-chrome-crawler');
(async () => {
const crawler = await HCCrawler.launch({
// Function to be evaluated in browsers
evaluatePage: (() => ({
title: $('title').text(),
})),
// Function to be called with evaluated results from browsers
onSuccess: (result => {
console.log(result);
}),
});
// Queue a request
await crawler.queue('https://example.com/');
// Queue multiple requests
await crawler.queue(['https://example.net/', 'https://example.org/']);
// Queue a request with custom options
await crawler.queue({
url: 'https://example.com/',
// Emulate a tablet device
device: 'Nexus 7',
// Enable screenshot by passing options
screenshot: {
path: './tmp/example-com.png'
},
});
await crawler.onIdle(); // Resolved when no queue is left
await crawler.close(); // Close the crawler
})();- Priority queue for crawling efficiency
- Emulate device and user agent
- Redis cache to skip duplicate requests
- Export a CSV file for crawled results
- Conditionally saving screenshots
See here for the full examples list. The examples can be run from the root folder as follows:
NODE_PATH=../ node examples/priority-queue.jsSee here for the API reference.
See here for the debugging tips.
- Upgraded Puppeteer to version 19 and Node to v18 (envinfo below)
- New Headless Chrome API
- Integrated ttkingdom's, sylturner's, viltgroup's, rmhubbert's forked repositories
- Added two stealth NPM modules puppeteer-extra-plugin-stealth and puppeteer-extra
- Tests passing. Run
npm run jest-exclude-redis-cache
$ npx envinfo --preset jest
System:
OS: macOS 13.3.1
CPU: (8) arm64 Apple M2
Binaries:
Node: 18.16.0 - ~/.nvm/versions/node/v18.16.0/bin/node
Yarn: 1.22.19 - ~/.nvm/versions/node/v18.16.0/bin/yarn
npm: 9.5.1 - ~/.nvm/versions/node/v18.16.0/bin/npm
npmPackages:
jest: ^29.5.0 => 29.5.0
There are roughly two types of crawlers. One is static and the other is dynamic.
The static crawlers are based on simple requests to HTML files. They are generally fast, but fail scraping the contents when the HTML dynamically changes on browsers.
Dynamic crawlers based on PhantomJS and Selenium work magically on such dynamic applications. However, PhantomJS's maintainer has stepped down and recommended to switch to Headless Chrome, which is fast and stable. Selenium is still a well-maintained cross browser platform which runs on Chrome, Safari, IE and so on. However, crawlers do not need such cross browsers support.
This crawler is dynamic and based on Headless Chrome.
This crawler is built on top of Puppeteer.
Puppeteer provides low to mid level APIs to manupulate Headless Chrome, so you can build your own crawler with it. This way you have more controls on what features to implement in order to satisfy your needs.
However, most crawlers requires such common features as following links, obeying robots.txt and etc. This crawler is a general solution for most crawling purposes. If you want to quickly start crawling with Headless Chrome, this crawler is for you.