A Guide on How to Build a Web Scraper- NetNut

 Introduction

How to build a web scraper is a crucial topic as it involves collecting data from a web page and saving it in a readable format. Understanding how to build a web scraper helps you with the task of extracting the HTML code from a website and then parsing it to extract required data. In simpler terms, the task of how to build a web scraper involves collecting data from a website with bots.

Manually copying, pasting, sorting, and organizing data can be daunting. Data is critical for making informed decisions that optimize digital marketing strategies and operations. Therefore, brands need to understand how to build a web scraper to optimize this process.

Now, you are probably wondering, “what can I do to learn how to build a web scraper?”.

This guide will provide a step-by-step guide on how to build a web scraper from scratch. In addition, we shall consider a scalable and effective alternative that you can use to fetch data from any website in any part of the world.

Let us dive in!

How do web scrapers work?

Web scrapers-the product of how to build a web scraper, are bots that can collect data from web pages. They work by fetching a URL, parsing the HTML, and storing the returned data in the desired format, like JSON or CSV. When you learn how to build a web scraper, the bots are used to automate the process of extracting data from websites. You can also use the knowledge of how to build a web scraper to retrieve specific information from a certain website. Alternatively, you can learn how to build a web scraper to extract all the data on a web page. 

The process of how to build a web scraper begins with identifying a target website containing the data you want to extract. Typically, the task of how to build a web scraper allows you to send a request to the website. However, you should consider using proxies due to anti-scraping techniques like CAPTCHAs, which could lead to an IP block. They assign your device a different IP address to hide your real identity. Consequently, understanding how to build a web scraper optimizes the process of extracting data from websites.

Once you enter the website’s address in the web scraper, it returns data to your computer as text, CSV, JSON, or others.

There are three primary constituents for the task of how to build a web scraper. First, if you are exploring how to build a web scraper, it requires a web scraping code that allows it to send a request to the website. The second is a function for parsing and collecting data; the third component in how to build a web scraper is a function for saving and exporting extracted data.

Prerequisites to learning how to build a web scraper

Before we dive into the intricacy of how to build a web scraper, let us examine what it takes for it to happen. Remember that the basic concept of how to build a web scraper involves identifying data and converting it into a useful format that can be stored on a computer. If you want to know how to build a web scraper, you need a programming language. 

Several programming languages can be used to write the code, but we will focus on Python for the task of how to build a web scraper. Python is one of the most widely used languages to learn how to build a web scraper. This may be attributed to its simplicity, ease of use, and extensive libraries that can streamline the process of how to build a web scraper. 

In addition, you need to understand HTML structures and various data formats on how to build a web scraper. Success with the task of how to build a web scraper is not the end of it; you must be able to receive specified data in a preferred form.  

To ensure you understand how to build a web scraper, this guide will cover the basic prerequisites you must know. They include:

HTML structure

HTML tags

If you are not tech-savvy, you are probably unfamiliar with the structure of HTML. And to learn how to build a web scraper, you would need to have some knowledge about HTML structures. An excellent place to begin is the Google developer tool on Chrome. 

Chrome is a popular search engine that is great for exploring how to build a web scraper. Visit any web address on your Google Chrome. Right-click and select “inspect” to view the HTML elements on the page. Alternatively, you can click on the three dots on the far right side of the browser. Then, select More Tools > Developers Tools to examine the HTML elements. 

Don’t worry; you don’t need to learn how to build an HTML site from scratch, like I said earlier, you only need a bit of knowledge of HTML structures to know how to build a web scraper. For instance, you only need to understand the basic structure of web pages to know how to identify specific web elements. 

Chrome and other browsers like Firefox visually represent the tags on the web page in the process of how to build a web scraper. In addition, it allows you to see other attributes like “class,” which is useful when you want to scrape specific elements. 

All the elements in the HTML structure are contained within the opening and closing “body” tags. Elements nested within an HTML structure indicate that it is a child element of its parent element.

To know how to build a web scraper, it is helpful to identify elements based on the tag name as well as determine if it is a child or parent element. 

HTML elements

Let us consider this example:

<h1 class= “aClass” id= “id_0” > This is a header tag</h1>

The efficiency of the task of how to build a web scraper depends on the instructions you write in the code. Therefore, understanding which element to specify can significantly affect the response returned in the process of how to build a web scraper. 

For example, in the code, we indicate <h1> elements as what we want to scrape. As indicated above, if there is only one h1, everything goes smoothly. 

However, what if there are multiple h1s, and you don’t need them all?

In such cases, you must specify which <h1> you want to scrape. You can specify this by including the “class” attributes. Subsequently, if this is not enough to tell Python the exact area you want to extract data, you need to add the “id” attributes. This will help Python hone in on a specific segment and collect only that specified data from the website. 

Understanding Python basics you need to know how to build a web scraper

You can learn how to build a web scraper with Python, JavaScript, Golang, Java, PHP, and others. Therefore, if you want to understand how to build a web scraper, you must understand some basic concepts in Python. 

Install Python and supporting software

Since you need to create a Python script in your quest of how to build a web scraper, you need to download and install Python. Be sure to download the latest version (they often come with upgraded features) from Python’s official website for the task of how to build a web scraper.

The primary advantage of using Python for the process of how to build a web scraper is that its syntax is simple and easy to understand. Python is a popular language for the task of how to build a web scraper because of its active community and the vast libraries with rich features. Subsequently, you can proceed with how to build a web scraper with Python within minutes because all the necessary tools have been provided.

Another critical software you need for how to build a web scraper using python is the python code editor tool. The function of the code editor for the task of how to build a web scraper is to create, modify, and save program files. In addition, the code editor can identify and highlight any errors in your code. As a result, it optimizes your productivity and makes the process of writing codes for how to build a web scraper with Python more efficient.

Read the official documentation on installing Python and any code editor you choose. They come with explanations that may be useful in helping you solve some challenges associated with how to build a web scraper using python.

Create a Python project folder 

Creating a Python project folder is quite similar to creating a random folder on your computer. Create a new folder, either on your desktop or within another folder, and create a new file. For the task of how to build a web scraper, you need to create two files- you can give them any name you desire. 

The files will be empty because you have not retrieved any data in the process of how to build a web scraper. Here is a picture that describes the process:

Website HTML             Web scraper (Python)            Saved data             Parse data

The raw HTML data is on the website, which you can scrape with the process of how to build a web scraper built with Python. The data is saved in your preferred format and then parsed to find useful information. Python script will handle data collection and data parsing for the process of how to build a web scraper. . 

Python Virtual Environments

One last thing to set up is the virtual environments for the task of how to build a web scraper. Using Python often involves libraries- packages that contain additional functionality to streamline how to build a web scraper. For this guide, we shall consider two of the most popular libraries- Request and BeautifulSoup. 

The Request library allows you to send HTTP requests to the website where you intend to extract their data. Once the package is running, the HTTP request returns a response object with all the response data, including encoding, status, encoding, and more.

On the other hand, BeautifulSoup is an excellent choice that parses XML and HTML documents. Moreover, it can convert an invalid markup into a parse tree. Therefore, it offers you the flexibility to implement various parsing strategies when learning how to build a web scraper.

Therefore, you need to install these libraries before you can proceed on how to build a web scraper. However, if you try to develop other applications, the functionalities of the libraries may be affected. For example, one application can use version 1 of the Request library while another application uses the version. This could potentially lead to some conflict, which is why it is necessary to set up a virtual environment.

The Python virtual environment serves as a capsule for the applications. When you create a virtual environment for application 1, it encapsulates it so that it can run on Request library version 1 without interfering with application 2, which runs on version 2 of the Request library. 

Now, let us discuss the terminal window- this is because the next set of commands is easier to run from the terminal. If you are using OS X to know how to build a web scraper, open the Applications folders and then open the Utilities folder, where you will find the Terminal application. 

However, if you want to use Windows to learn how to build a web scraper, you can find the terminal line by going to the Start Menu and searching. It is an app that you can find at C:\Windows\System32.

Once the terminal is open, navigate to the project folder and build the virtual environment. You can use this code:

python3 –m venv tutorial-env 

Bravo! You have successfully created the virtual environment in your quest of how to build a web scraper. However, it is still dormant, so you need to activate it before you can use it. 

Here is the code to active the virtual environment you need to understand how to build a web scraper:

For Windows:

Tutorial-env\Scripts\activate.bat

For Mac: source tutorial-env/bin/activate

Python libraries 

Installing Libraries

The next step of how to build a web scraper is to install the libraries we discussed above- Request and BeautifulSoup. At this time, the terminal becomes incredibly useful again- you can install the libraries with the pip installer. The command is shown below:

To install BeautifulSoup: pip install bs4

To install Request: pip install requests

Importing libraries

After installing the libraries, you need to import them before you can proceed with the task of how to build a web scraper. The first step is to notify Python that you are going to use the Libraries you have installed. You can do this by importing the Libraries into the Python file. We recommend arranging the imported libraries at the top of the file so they are easily accessible. 

Here is the code you need to import the two libraries into the file:

From bs4 import, BeautifulSoul import requests

Before you can proceed with how to build a web scraper, you need to use the pip installer to install other Python libraries. Always remember to import them to the top of your file. However, bear in mind that some libraries are large and take up lots of memory. Therefore, consider the size of the project when considering the libraries you want to import in your task of how to build a web scraper. 

Python’s Requests and BeautifulSoup Library

Requests with Python and BeautifulSoup usually have three parts. They include:

• URL- this is the web address of the page you want to scrape data, such as www.example.com
• Response- get (URL)
• Content- BeautifulSoup (response.content, “html.parser”)

The URL is a string containing the website address, while the RESPONSE is the result of the “GET” Request. The URL is also a variable in the GET request, while the response is an HTTP status code. 

If the web scraper request is successful, you will receive a “successful” status code. However, if the Request failed, it could be that the server did not respond as anticipated, and the status code will be “unsuccessful.” To solve this challenge, you may need to troubleshoot the error. In addition, the “CONTENT” is the content of the response. It contains the data on the website you want to scrape.

Getting data from the web begins with HTTP requests like “Post” or “Get” to the website, which returns a response containing the data. One of the challenges of using Python HTTP libraries is the difficulty of using them because they often require bulky lines of code. However, the request library simplifies this problem by using less bulky codes, which are easier to understand and implement, and in the end makes learning how to build a web scraper an easy task.

Regardless of the benefit of simplicity that comes with the request package, it has a limitation when used in how to build a web scraper. This library does not parse the extracted HTML data. In simpler terms, it cannot convert data scraped from the internet into a readable form ready for analysis. In addition, you cannot use the Request library to build web scrapers for websites that were written with only JavaScript.

BeautifulSoup is an excellent choice that parses XML and HTML documents. Moreover, it can convert an invalid markup into a parse tree. Therefore, it offers you the flexibility of implementing various parsing strategies in how to build a web scraper.

Beautiful Soup is limited because its unique function is parsing data. Therefore, it cannot be used to request data from the internet. As a result, it is often used together with the Python Request Package in how to build a web scraper.

Since Beautiful Soup makes it easy to navigate and modify the parse tree, it is ideal for beginners. Also, expert developers opt for this library because it saves them several hours. For example, in how to build a web scraper to print all the blog titles on a web page, you can include the “find_all ()” method.

 Another unique function of this library is broken HTML parsing. In addition, Beautiful Soup can detect page encoding, which further optimizes the authenticity of data extracted from the HTML file. 

Furthermore, you can customize Beautiful Soup with a few lines of code to identify and extract specific data in how to build a web scraper.

How to build a web scraper in Python

Let us examine a step-by-step guide of how to build a web scraper in Python

Step 1: Select the right Python scraping libraries 

Before you start on how to build a web scraper, you must first determine its purpose. This is because it affects the choice of the library that is suitable to build the web scraper. We have discussed Request and BeautifulSoup as well as the role they play in helping you with the task of how to build a web scraper. However, depending on your needs, you could install and import other Python libraries like Selenium.  

One of the first things to do to determine your needs in how to build a web scraper is to visit the target site in your browser. Right-click on anywhere in the background and select inspect to display the DevTools. 

If the target website was written in only JavaScript, then you need to install and import Selenium in your process of how to build a web scraper. Read a recent guide that explores the uses, pros, and cons of Python libraries here.

Step 2: Initialize a Python project

 The next step is to set up your Python project- you only need a single .py file. However, you can use an advanced Integrated Development Environment to optimize how to build a web scraper. For this guide, we shall set up a Python project in PyCharm, although other Python IDEs can be used.

Open PyCharm and select “File > New Project,” then in the popup window, select “Pure Python” and create a new project. By default, PyCharm will initialize a main .py file. Let’s say you name the file “extract,” it becomes “extract.py.”

Install and import any Python library you want to use in your process of how to build a web scraper at the top of the script. You may need to install them again if the libraries appear in red. 

Step 3: Connect to the target URL

To know how to build a web scraper, you need to know how to connect to the target URL. You must copy the entire URL of the target website from your browser. Be sure to include the HTTP section ( either https or http) to avoid getting an error response. For example, the URL is “https://www.example.com.”

Once you have copied the URL, use the request library to download the page as shown below:

Page = Request.get ( ‘https://www.example.io)

If the Request was successful, the HTTP 200 OK status response code indicates it has been executed. However, a 4xx or 5xx HTTP status code indicates the Request was not successful. 

One of the major reasons for a failed request is that websites block requests without a valid User-Agent.

Step 4: Parse the HTML content

When you proceed with how to build a web scraper, BeautifulSoup becomes necessary at this stage. The code should look like this:

Soup= BeautifulSoup (page.text, ‘html.parser’) 

The soup variable above contains a BeautifulSoup object. This is a tree structure generated from parsing the HTML document in the page.text with the built-in html.parser feature

Step 5: Use BeautifulSoup to select HTML elements

BeautifulSoup has various methods for selecting elements from the DOM when used in how to build a web scraper. It often begins with :

Find ()- This returns the first HTML element that matches the input selector if specified.

Find_all (): This returns a list of HTML elements that match the selector condition passed as a parameter.

When dealing with how to build a web scraper, it will look for data on a web page based on the input of the two methods above. In addition, when you progress with how to build a web scraper, you can select specific HTML elements by:

• Tag
• Id
• Text
• Attribute
• Class

When you combine these methods in how to build a web scraper, you can extract any HTML element from the web page.

An alternative offered by BeautifulSoup is the select() method, which allows you to apply a CSS selector directly when you proceed with how to build a web scraper. 

You can use the following CSS selectors on .quote, and they include:

• .text
• .author
• .tags

Step 6: Data extraction from the elements

You need a data structure to specify where to store the data. For this guide, you can initialize an array variable “quotes = [ ].”

Moving on, you can use soup to extract the quote element from the DOM by applying the .quote CSS selector discussed in earlier steps on how to build a web scraper guide.

The BeautifulSoup find() method will extract the single HTML element you need. If the tag strings associated with the quote are more than one, it may be best to store them in a list. 

Step 7: Save the scraped data into a CSV file

The next step is to determine where the actual data extraction occurs. For this step, the web scraper iterates every page and stores the data in a readable format like CSV. Moreover, you have to create a CSV file with open(). Then, you can fill it up with the writerow() function from the Writer object of the CSV library. 

Following the above command, the data is stored in CSV format. Once you have stored data, you have successfully built and utilized a web scraper. At this point, you must now know how to build a web scraper.

Why use Python for the task of how to build a web scraper?

Here are some reasons to use Python when you learn how to build a web scraper:

1. Automation: One of the primary reasons to use Python in how to build a web scraper is automation. Data scraping activities can be a constant event, especially for an organization that needs to stay updated. Therefore, with the Python service, you can proceed with how to build a web scraper designed to extract data at various intervals.
2. Compatibility: Since Python is a programming language, it can be used across various platforms. This feature makes it a top choice for how to build a web scraper. Regardless of your device- macOS, windows, or Linux, you can use Python in the process of how to  build a web scraper. Subsequently, there is flexibility in how to build a web scraper without limitation to the device’s operating system.
3. Libraries: Python stands out as an option in how to build a web scraper because of the availability of resources, including libraries. These libraries make it easier for you to progress with how to build a web scraper within a short time. 
4. Data structuring: Another reason to use Python in how to build a web scraper is the HTTPS libraries. They play a significant role in cookies settings, authentication, and a range of data scraping to optimize the process of data collection.
5. Customization: If you want to facilitate how to build a web scraper with customized features, then you can’t go wrong with Python. You can adopt the process of how to build a web scraper with customized commands to retrieve data at scheduled intervals so that your business always stays up-to-date with relevant information.
6. Integration with proxy: Integration with proxy is a critical point of consideration when you faced with the task of how to build a web scraper. Python can be integrated with proxy services to ensure anonymity and bypass IP blocking services. Therefore, it is an ideal choice in the process of how to build a web scraper.
7. Robust community: When you decide to proceed with how to build a web scraper, you may face some challenges. Python services have a large community of experts and enthusiasts. Therefore, you can always find relevant information, answers, and videos to assist you in how to build a web scraper. 

Integrating NetNut with Python for the task of how to build a web scraper

Why do you need to integrate Python with NetNut for the task of how to build a web scraper?

Regardless of the language and tools to use in how to build a web scraper, it will face some challenges. They include anti-bot and anti-scraping measures, which have become more popular.  

So, how can you progress with how to build a web scraper that performs its duties regardless of these measures? That is where NetNut proxies come in. With NetNut, you can learn how to build a web scraper, prioritize integration with a proxy to achieve your desired goal.

A proxy serves as a middleman between the script used to build a web crawler and the target site. When you know how to build a web scraper, the goal is to use it to send a Request, but a proxy receives the Request instead and sends it. Then, the proxy receives the response from the website and sends it back to you. Consequently, your IP address remains hidden as the target site will only have access to that of the proxy servers. 

Netnut is an industry-leading expert that offers top-notch proxy servers with reputable IPs. We have an extensive network of over 52 million rotating residential proxies in 200 countries and over 250,000 mobile IPS in over 100 countries, which helps them provide exceptional data collection services.

When you have finally learned how to build a web scraper, integrating it with NetNut rotating residential proxies ensures you can access websites despite geographic restrictions. 

Alternatively, instead of spending several hours on how to build a web scraper, you can use our in-house solution- NetNut Scraper API, to access websites and collect data. Moreover, if you need customized web scraping solutions, you can use NetNut’s Mobile Proxy. 

Not sure which option to integrate with Python on how to build a web scraper? Contact NetNut to speak to one of our experts today!

Conclusion

This guide has examined how to build a web scraper by leveraging Python. We also looked at what web scraping is, how it works, and why Python is an excellent language for how to build a web scraper. Then, we explored how to use the Request Library and Beautiful Soup to in the process of how to build a web scraper. 

Data has become a cornerstone in decision-making, especially for big brands. Therefore, learning how to build a web scraper is a critical skill. If you want to move forward with how to build a web scraper, it begins with identifying the data, inspecting the HTML structure of the website, and writing the code. Once you have extracted the data, save it in a usable format for further analysis. 

Frequently Asked Questions

Is Python an ideal language for the task of how to build a web scraper?

Python is often considered as one of the best languages to facilitate how to build a web scraper. It has a low learning curve, which translates to its simplicity. Therefore, it has become an excellent programming language for beginners who want to explore how to build a web scraper. 

In addition, it has the largest community of active members. It is easy to feel overwhelmed when you decide to explore how to build a web scraper. However, interacting with people of similar interests can make it easier to learn how to build a web scraper.

What is the process of how to build a web scraper to extract specific data from a website?

Yes, you can proceed with how to build a web scraper to extract specific data from a website. The first step is to inspect the target URL, identify the specific data you want to extract and its HTML characteristics, and write the code for how to build a web scraper.

What other languages can be used for the task of how to build a web scraper?

Apart from Python, there are several other languages that you can use for the process of how to build a web scraper. They include Java, C++, PHP, JavaScript, Node.js, Ruby, and others. Using any of these programming languages for the task of how to build a web scraper has unique pros and cons.