Web scraping isn’t new. However, the technologies and techniques that are used to power websites are developing at a rapid speed. A lot of websites use front-end frameworks like Vuejs, react, or angular, that load (partial) content asynchronously via javascript. Hence, this content can only be fetched if the page is opened in a web browser. So what’s web scraping anyway? It involves automating away the laborious task of collecting information from websites. There are a lot of use cases for web scraping: you might want to collect prices from various e-commerce sites for a price comparison site. Or perhaps you need flight times and hotel/AirBNB listings for a travel site. Web scraping at full power. With these tools we can log into sites, click, scroll, execute JavaScript and more. Cloud Functions + Scheduler Many scrapers are useless unless you deploy them.
Some websites can contain a very large amount of invaluable data.
Stock prices, product details, sports stats, company contacts, you name it.
Jsdom: jsdom is a pure-JavaScript implementation of many web standards, notably the WHATWG DOM and HTML Standards, for use with Node.js. In general, the goal of the project is to emulate enough of a subset of a web browser to be useful for testing and scraping real-world web applications. Introduction By definition, web scraping means getting useful information from web pages. The process should remove the hassle of having to browse pages manually, be automated, and allow to gather and classify the information you're interested in programmatically. Node.js is a great tool to use for web scraping.
If you wanted to access this information, you’d either have to use whatever format the website uses or copy-paste the information manually into a new document. Here’s where web scraping can help.
What is Web Scraping?
Web scraping refers to the extraction of data from a website. This information is collected and then exported into a format that is more useful for the user. Be it a spreadsheet or an API.
Although web scraping can be done manually, in most cases, automated tools are preferred when scraping web data as they can be less costly and work at a faster rate.
But in most cases, web scraping is not a simple task. Websites come in many shapes and forms, as a result, web scrapers vary in functionality and features.
If you want to find the best web scraper for your project, make sure to read on.
How do Web Scrapers Work?
Automated web scrapers work in a rather simple but also complex way. After all, websites are built for humans to understand, not machines.
First, the web scraper will be given one or more URLs to load before scraping. The scraper then loads the entire HTML code for the page in question. More advanced scrapers will render the entire website, including CSS and Javascript elements.
Then the scraper will either extract all the data on the page or specific data selected by the user before the project is run.
Ideally, the user will go through the process of selecting the specific data they want from the page. For example, you might want to scrape an Amazon product page for prices and models but are not necessarily interested in product reviews.
Lastly, the web scraper will output all the data that has been collected into a format that is more useful to the user.
Most web scrapers will output data to a CSV or Excel spreadsheet, while more advanced scrapers will support other formats such as JSON which can be used for an API.
What Kind of Web Scrapers are There?
Web scrapers can drastically differ from each other on a case-by-case basis.
For simplicity’s sake, we will break down some of these aspects into 4 categories. Of course, there are more intricacies at play when comparing web scrapers.
- self-built or pre-built
- browser extension vs software
- User interface
- Cloud vs Local
Self-built or Pre-built
Just like how anyone can build a website, anyone can build their own web scraper.
Typescript Web Scraper
However, the tools available to build your own web scraper still require some advanced programming knowledge. The scope of this knowledge also increases with the number of features you’d like your scraper to have.
On the other hand, there are numerous pre-built web scrapers that you can download and run right away. Some of these will also have advanced options added such as scrape scheduling, JSON and Google Sheets exports and more.
Browser extension vs Software
In general terms, web scrapers come in two forms: browser extensions or computer software.
Browser extensions are app-like programs that can be added onto your browser such as Google Chrome or Firefox. Some popular browser extensions include themes, ad blockers, messaging extensions and more.
Web scraping extensions have the benefit of being simpler to run and being integrated right into your browser.
However, these extensions are usually limited by living in your browser. Meaning that any advanced features that would have to occur outside of the browser would be impossible to implement. For example, IP Rotations would not be possible in this kind of extension.
Web Scraping Node Js
On the other hand, you will have actual web scraping software that can be downloaded and installed on your computer. While these are a bit less convenient than browser extensions, they make up for it in advanced features that are not limited by what your browser can and cannot do.
User Interface
The user interface between web scrapers can vary quite extremely.
For example, some web scraping tools will run with a minimal UI and a command line. Some users might find this unintuitive or confusing.
Axios Web Scraping
On the other hand, some web scrapers will have a full-fledged UI where the website is fully rendered for the user to just click on the data they want to scrape. These web scrapers are usually easier to work with for most people with limited technical knowledge.
Some scrapers will go as far as integrating help tips and suggestions through their UI to make sure the user understands each feature that the software offers.
Cloud vs Local
From where does your web scraper actually do its job?
Local web scrapers will run on your computer using its resources and internet connection. This means that if your web scraper has a high usage of CPU or RAM, your computer might become quite slow while your scrape runs. With long scraping tasks, this could put your computer out of commission for hours.
Additionally, if your scraper is set to run on a large number of URLs (such as product pages), it can have an impact on your ISP’s data caps.
Cloud-based web scrapers run on an off-site server which is usually provided by the company who developed the scraper itself. This means that your computer’s resources are freed up while your scraper runs and gathers data. You can then work on other tasks and be notified later once your scrape is ready to be exported.
This also allows for very easy integration of advanced features such as IP rotation, which can prevent your scraper from getting blocked from major websites due to their scraping activity.
What are Web Scrapers Used For?
By this point, you can probably think of several different ways in which web scrapers can be used. We’ve put some of the most common ones below (plus a few unique ones).
- Scraping site data before a website migration
- Scraping financial data for market research and insights
The list of things you can do with web scraping is almost endless. After all, it is all about what you can do with the data you’ve collected and how valuable you can make it.
Read our Beginner's guide to web scraping to start learning how to scrape any website!
The Best Web Scraper
So, now that you know the basics of web scraping, you’re probably wondering what is the best web scraper for you?
The obvious answer is that it depends.
The more you know about your scraping needs, the better of an idea you will have about what’s the best web scraper for you. However, that did not stop us from writing our guide on what makes the Best Web Scraper.
Of course, we would always recommend ParseHub. Not only can it be downloaded for FREE but it comes with an incredibly powerful suite of features which we reviewed in this article. Including a friendly UI, cloud-based scrapping, awesome customer support and more.
Want to become an expert on Web Scraping for Free? Take ourfree web scraping courses and become Certified in Web Scraping today!
In this article, I’d like to list some most popular Javascript open-source projects that can be useful for web scraping. It consists of both libraries and standalone niche scrapers that can scrape a particular site (Amazon, iTunes, Instagram, Google Play, etc.)
Awesome Open Source Javascript Projects for Web Scraping#
HTTP interaction#
- Axios: Promise based HTTP client for the browser and node.js.
Features: XMLHttpRequests from the browser, HTTP requests from node.js, Promise API, intercepting of request and response, transforming of request and response, automatic transforming for JSON data. - Got: Human-friendly and powerful HTTP request library for Node.js.
Features: HTTP/2 support, Promise API, Stream API, Pagination API, Cookies (out-of-box), Progress events. - Superagent: Small progressive client-side HTTP request library, and Node.js module with the same API, supporting many high-level HTTP client features.
Features: HTTP/2 support, Promise API, Stream API, Request cancelation, Follows redirects, Retries on failure, Progress events.
DOM manipulation and HTML parsing#
- Cheerio: Fast, flexible & lean implementation of core jQuery designed specifically for the server.
Cheerio parses markup and provides an API for traversing/manipulating the resulting data structure. It does not interpret the result as a web browser does. Specifically, it does not produce a visual rendering, apply CSS, load external resources, or execute JavaScript. - jsdom:
jsdomis a pure-JavaScript implementation of many web standards, notably the WHATWG DOM and HTML Standards, for use with Node.js. In general, the goal of the project is to emulate enough of a subset of a web browser to be useful for testing and scraping real-world web applications. - htmlparser2: A forgiving HTML/XML/RSS parser. The parser can handle streams and provides a callback interface.This module started as a fork of the
htmlparsermodule. The main difference is thathtmlparser2is intended to be used only with NodeJs (it runs on other platforms usingbrowserify).htmlparser2was rewritten multiple times and, while it maintains an API that's compatible with htmlparser in most cases, the projects don't share any code anymore.
Javascript execution and rendering#
- Puppeteer: Puppeteer is a NodeJS library that provides a high-level API to control Chrome or Chromium over the DevTools Protocol. Puppeteer runs headless by default, but can be configured to run full (non-headless) Chrome or Chromium.
- Awesome resources for Puppeteer: https://github.com/transitive-bullshit/awesome-puppeteer
- Selenium: Selenium is an umbrella project encapsulating a variety of tools and libraries enabling web browser automation. Selenium specifically provides an infrastructure for the W3C WebDriver specification — a platform and language-neutral coding interface compatible with all major web browsers.
- Playwright: Playwright is a Node library to automate Chromium, Firefox, and WebKit with a single API. Playwright is built to enable cross-browser web automation that is ever-green, capable, reliable, and fast.
- PhantomJS: PhantomJS (phantomjs.org) is a headless WebKit scriptable with JavaScript. Fast and native implementation of web standards: DOM, CSS, JavaScript, Canvas, and SVG. No emulation!
Resource scrapers#
- amazon-scraper: Useful tool to scrape product information from the amazon
- app-store-scraper: Node.js module to scrape application data from the iTunes/Mac App Store.
- instagram-scraper: Since Instagram has removed the option to load public data through its API, this actor should help replace this functionality.
- google-play-scraper: Node.js module to scrape application data from the Google Play store.
- scrapedin: Scraper for LinkedIn full profile data. Unlike other scrapers, it's working in 2020 with their new website.
- tiktok-scraper: Scrape and download useful information from TikTok.
And it's only the most interesting ones. Feel free to browse through Github to find out your best one!
Conclusion#
JavaScript is not as popular a programming language for web scrapers as Python, but the community is growing and this list definitely will get bigger over some time.
Web Scraping Using Js
Also, our scraping API is language agnostic, so you can check it even if you're not very familiar with JS or Python.