You may require C#, one of the most well-liked backend programming languages, in order to scrape a webpage (or several pages). We will discuss how to use C# to scrape a webpage in this article. We'll specifically guide you through the process of sending the HTTP request, using C# to interpret the HTML page you receive, and accessing and extracting the desired information.

Part I: Configuring Static Pages

It is quite likely that you are already familiar with Visual Studio if you work with C#. This post utilizes an MVC (Model View Controller)-based simple .NET Core Web Application project. Once a new project has been established, add the required libraries for this lesson using the NuGet package manager.

To retrieve the package from NuGet, select the "Browse" option and input "HTML Agility Pack."

Once the package is installed, you may begin using it. Finding tags and information you wish to keep from the downloaded HTML is made simple with this package.

Using C# to Send an HTTP Request to a Web Page

Consider that you are required to scrape Wikipedia in order to find information on well-known software developers for a project. Without an article like this, Wikipedia wouldn't be what it is today, would it? 

This is only a basic illustration of what can be done with web scraping, but the idea is to locate a website containing the data you want, use C# to extract the material, and save it for later use. Using the links on a top category page, you may crawl sites in more complicated projects.

Using the HttpClient in.NET Framework to Retrieve HTML.NET comes pre-installed with an HTTP client (called HttpClient).No extra third-party libraries or dependencies are required because Net.Http is the namespace used. Moreover, it comes with built-in support for asynchronous calls.

Understanding HTML

It's now time to parse the HTML that has been obtained. One well-liked parser suite is HTML Agility Pack, which is also readily paired with LINQ, for example.

To ensure that you precisely extract the right components, you need to have a basic understanding of the page's structure before beginning to parse the HTML. The developer tools in your browser will come into their own at this point as they let you examine the DOM tree in great depth.

We'll see from our Wikipedia page that our Table of Contents has many links; we won't need those. Many more links (such as the edit links) are there as well, but they are not necessary for our data collection. 

XPath

Notably, there would have been no need for us to choose the elements by hand. We only took this action as an example.

Using an XPath expression will be far more convenient in real-world coding. That would allow our entire selection reasoning to fit into a single sentence.

Part Two: Gathering Dynamic JavaScript Web Pages

Because the entire HTML text was already sent to us from the server, all we had to do in Part I of the scraping process was parse it and choose the desired data.

However, the situation has changed due to JavaScript, and websites that largely rely on it—especially those created with Angular, React, or Vue.js—cannot be scrapped in the manner we previously explained. If you followed the same procedure, you would mostly receive JavaScript code instead of much HTML. To access the desired data, the JavaScript function must be actually executed.

Conclusion

All the tools and frameworks you need to create your own data scraper are available in C# and.NET in general. Puppeteer and Selenium in particular make it simple to rapidly build a crawler project and obtain the data you need.

We just touched on a few of the methods to prevent being banned or having your rate capped by the server. Usually, more than any technological restrictions, that is the true challenge with web scraping.