6 Essential Web Scraping Frameworks with JavaScript

In today's post we will learn about 6 Essential Web Scraping Frameworks with JavaScript.

What is a Web Scraping?

Web scraping is the process of collecting structured web data in an automated fashion. It’s also called web data extraction. Some of the main use cases of web scraping include price monitoring, price intelligence, news monitoring, lead generation, and market research among many others.

In general, web data extraction is used by people and businesses who want to make use of the vast amount of publicly available web data to make smarter decisions.

If you’ve ever copied and pasted information from a website, you’ve performed the same function as any web scraper, only on a microscopic, manual scale. Unlike the mundane, mind-numbing process of manually extracting data, web scraping uses intelligent automation to retrieve hundreds, millions, or even billions of data points from the internet’s seemingly endless frontier.

Table of contents:

• Webparsy - NodeJS lib and cli for scraping websites using Puppeteer and YAML.
• Node-crawler - Web Crawler/Spider for NodeJS + server-side jQuery.
• Node-simplecrawler - Flexible event driven crawler for node.
• Crawlee - Node.js and TypeScript library that crawls with Cheerio, JSDOM, Playwright and Puppeteer while enhancing them with anti-blocking features, queue, storages and more.
• Ayakashi.io - The next generation web scraping framework. 
• Pjscrape - A web-scraping framework written in Javascript, using PhantomJS and jQuery.

1 - Webparsy: NodeJS lib and cli for scraping websites using Puppeteer and YAML.

Overview

You can use WebParsy either as cli from your terminal or as a NodeJS library.

Cli

Install webparsy:

$ npm i webparsy -g

$ webparsy example/_weather.yml --customFlag "custom flag value"
Result:

{
  "title": "Madrid, España Pronóstico del tiempo y condiciones meteorológicas - The Weather Channel | Weather.com",
  "city": "Madrid, España",
  "temp": 18
}

Library

const webparsy = require('webparsy')
const parsingResult = await webparsy.init({
  file: 'jobdefinition.yml'
  flags: { ... } // optional
})

Methods

init(options)

options:

One of yaml, file or string is required.

• yaml: A yaml npm module instance of the scraping definition.
• string: The YAML definition, as a plain string.
• file: The path for the YAML file containing the scraping definition.

Additionally, you can pass a flags object property to input additional values to your scraping process.

View on Github

2 - Node-crawler: Web Crawler/Spider for NodeJS + server-side jQuery.

Install

$ npm install crawler

Basic usage

const Crawler = require('crawler');

const c = new Crawler({
    maxConnections: 10,
    // This will be called for each crawled page
    callback: (error, res, done) => {
        if (error) {
            console.log(error);
        } else {
            const $ = res.$;
            // $ is Cheerio by default
            //a lean implementation of core jQuery designed specifically for the server
            console.log($('title').text());
        }
        done();
    }
});

// Queue just one URL, with default callback
c.queue('http://www.amazon.com');

// Queue a list of URLs
c.queue(['http://www.google.com/','http://www.yahoo.com']);

// Queue URLs with custom callbacks & parameters
c.queue([{
    uri: 'http://parishackers.org/',
    jQuery: false,

    // The global callback won't be called
    callback: (error, res, done) => {
        if (error) {
            console.log(error);
        } else {
            console.log('Grabbed', res.body.length, 'bytes');
        }
        done();
    }
}]);

// Queue some HTML code directly without grabbing (mostly for tests)
c.queue([{
    html: '<p>This is a <strong>test</strong></p>'
}]);

Slow down

Use rateLimit to slow down when you are visiting web sites.

const Crawler = require('crawler');

const c = new Crawler({
    rateLimit: 1000, // `maxConnections` will be forced to 1
    callback: (err, res, done) => {
        console.log(res.$('title').text());
        done();
    }
});

c.queue(tasks);//between two tasks, minimum time gap is 1000 (ms)

View on Github

3 - Node-simplecrawler: Flexible event driven crawler for node.

Installation

npm install --save simplecrawler

Getting Started

Initializing simplecrawler is a simple process. First, you require the module and instantiate it with a single argument. You then configure the properties you like (eg. the request interval), register a few event listeners, and call the start method. Let's walk through the process!

After requiring the crawler, we create a new instance of it. We supply the constructor with a URL that indicates which domain to crawl and which resource to fetch first.

var Crawler = require("simplecrawler");

var crawler = new Crawler("http://www.example.com/");

You can initialize the crawler with or without the new operator. Being able to skip it comes in handy when you want to chain API calls.

var crawler = Crawler("http://www.example.com/")
    .on("fetchcomplete", function () {
        console.log("Fetched a resource!")
    });

By default, the crawler will only fetch resources on the same domain as that in the URL passed to the constructor. But this can be changed through the crawler.domainWhitelist property.

Now, let's configure some more things before we start crawling. Of course, you're probably wanting to ensure you don't take down your web server. Decrease the concurrency from five simultaneous requests - and increase the request interval from the default 250 ms like this:

crawler.interval = 10000; // Ten seconds
crawler.maxConcurrency = 3;

You can also define a max depth for links to fetch:

crawler.maxDepth = 1; // Only first page is fetched (with linked CSS & images)
// Or:
crawler.maxDepth = 2; // First page and discovered links from it are fetched
// Or:
crawler.maxDepth = 3; // Etc.

View on Github

4 - Crawlee: Node.js and TypeScript library that crawls with Cheerio, JSDOM, Playwright and Puppeteer while enhancing them with anti-blocking features, queue, storages and more.

Installation

We recommend visiting the Introduction tutorial in Crawlee documentation for more information.

Crawlee requires Node.js 16 or higher.

With Crawlee CLI

The fastest way to try Crawlee out is to use the Crawlee CLI and choose the Getting started example. The CLI will install all the necessary dependencies and add boilerplate code for you to play with.

npx crawlee create my-crawler

cd my-crawler
npm start

Manual installation

If you prefer adding Crawlee into your own project, try the example below. Because it uses PlaywrightCrawler we also need to install Playwright. It's not bundled with Crawlee to reduce install size.

npm install crawlee playwright

import { PlaywrightCrawler, Dataset } from 'crawlee';

// PlaywrightCrawler crawls the web using a headless
// browser controlled by the Playwright library.
const crawler = new PlaywrightCrawler({
    // Use the requestHandler to process each of the crawled pages.
    async requestHandler({ request, page, enqueueLinks, log }) {
        const title = await page.title();
        log.info(`Title of ${request.loadedUrl} is '${title}'`);

        // Save results as JSON to ./storage/datasets/default
        await Dataset.pushData({ title, url: request.loadedUrl });

        // Extract links from the current page
        // and add them to the crawling queue.
        await enqueueLinks();
    },
    // Uncomment this option to see the browser window.
    // headless: false,
});

// Add first URL to the queue and start the crawl.
await crawler.run(['https://crawlee.dev']);

By default, Crawlee stores data to ./storage in the current working directory. You can override this directory via Crawlee configuration. For details, see Configuration guide, Request storage and Result storage.

View on Github

5 - Ayakashi.io: The next generation web scraping framework. 

Ayakashi helps you build scraping and automation systems that are

• easy to build
• simple or sophisticated
• highly performant
• maintainable and built for change

Powerful querying and data models

Ayakashi's way of finding things in the page and using them is done with props and domQL.
Directly inspired by the relational database world (and SQL), domQL makes DOM access easy and readable no matter how obscure the page's structure is.
Props are the way to package domQL expressions as re-usable structures which can then be passed around to actions or to be used as models for data extraction.

High level builtin actions

Ready made actions so you can focus on what matters.
Easily handle infinite scrolling, single page navigation, events and more.
Plus, you can always build your own actions, either from scratch or by composing other actions.

Preload code on pages

Need to include a bunch of code, a library you made or a 3rd party module and make it available on a page?
Preloaders have you covered.

Control how you save your data

Automatically save your extracted data to all major SQL engines, JSON and CSV.
Need something more exotic or the ability to control exactly how the data is persisted?
Package and plug your custom logic as a script.

View on Github

6 - Pjscrape: A web-scraping framework written in Javascript, using PhantomJS and jQuery.

Overview

pjscrape is a framework for anyone who's ever wanted a command-line tool for web scraping using Javascript and jQuery. Built for PhantomJS, it allows you to scrape pages in a fully rendered, Javascript-enabled context from the command line, no browser required.

Features

• Client-side, Javascript-based scraping environment with full access to jQuery functions
• Easy, flexible syntax for setting up one or more scrapers
• Recursive/crawl scraping
• Delay scrape until a "ready" condition occurs
• Load your own scripts on the page before scraping
• Modular architecture for logging and writing/formatting scraped items
• Client-side utilities for common tasks
• Growing set of unit tests

View on Github

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Related videos:

Introduction To Web Scraping With Javascript

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