Python Modules for Web Scraping

In this chapter, let us learn various Python modules that we can use for web scraping.

Python Development Environments using virtualenv

Virtualenv is a tool to create isolated Python environments. With the help of virtualenv, we can create a folder that contains all necessary executables to use the packages that our Python project requires. It also allows us to add and modify Python modules without access to the global installation.

You can use the following command to install virtualenv −

(base) D:ProgramData>pip install virtualenv
Collecting virtualenv
   Downloading
https://files.pythonhosted.org/packages/b6/30/96a02b2287098b23b875bc8c2f58071c3
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Instalpng collected packages: virtualenv
Successfully installed virtualenv-16.0.0

Now, we need to create a directory which will represent the project with the help of following command −

(base) D:ProgramData>mkdir webscrap

Now, enter into that directory with the help of this following command −

(base) D:ProgramData>cd webscrap

Now, we need to initiapze virtual environment folder of our choice as follows −

(base) D:ProgramDatawebscrap>virtualenv websc
Using base prefix  d:\programdata 
New python executable in D:ProgramDatawebscrapwebscScriptspython.exe
Instalpng setuptools, pip, wheel...done.

Now, activate the virtual environment with the command given below. Once successfully activated, you will see the name of it on the left hand side in brackets.

(base) D:ProgramDatawebscrap>webscscriptsactivate

We can install any module in this environment as follows −

(websc) (base) D:ProgramDatawebscrap>pip install requests
Collecting requests
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Instalpng collected packages: chardet, certifi, urlpb3, idna, requests
Successfully installed certifi-2018.8.24 chardet-3.0.4 idna-2.7 requests-2.19.1
urlpb3-1.23

For deactivating the virtual environment, we can use the following command −

(websc) (base) D:ProgramDatawebscrap>deactivate
(base) D:ProgramDatawebscrap>

You can see that (websc) has been deactivated.

Python Modules for Web Scraping

Web scraping is the process of constructing an agent which can extract, parse, download and organize useful information from the web automatically. In other words, instead of manually saving the data from websites, the web scraping software will automatically load and extract data from multiple websites as per our requirement.

In this section, we are going to discuss about useful Python pbraries for web scraping.

Requests

It is a simple python web scraping pbrary. It is an efficient HTTP pbrary used for accessing web pages. With the help of Requests, we can get the raw HTML of web pages which can then be parsed for retrieving the data. Before using requests, let us understand its installation.

Instalpng Requests

We can install it in either on our virtual environment or on the global installation. With the help of pip command, we can easily install it as follows −

(base) D:ProgramData> pip install requests
Collecting requests
Using cached
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c4c3fdf57a284257925dfc12bda/requests-2.19.1-py2.py3-none-any.whl
Requirement already satisfied: idna<2.8,>=2.5 in d:programdatapbsitepackages
(from requests) (2.6)
Requirement already satisfied: urlpb3<1.24,>=1.21.1 in
d:programdatapbsite-packages (from requests) (1.22)
Requirement already satisfied: certifi>=2017.4.17 in d:programdatapbsitepackages
(from requests) (2018.1.18)
Requirement already satisfied: chardet<3.1.0,>=3.0.2 in
d:programdatapbsite-packages (from requests) (3.0.4)
Instalpng collected packages: requests
Successfully installed requests-2.19.1

Example

In this example, we are making a GET HTTP request for a web page. For this we need to first import requests pbrary as follows −

In [1]: import requests

In this following pne of code, we use requests to make a GET HTTP requests for the url: https://authoraditiagarwal.com/ by making a GET request.

In [2]: r = requests.get( https://authoraditiagarwal.com/ )

Now we can retrieve the content by using .text property as follows −

In [5]: r.text[:200]

Observe that in the following output, we got the first 200 characters.

Out[5]:  <!DOCTYPE html>
<html lang="en-US"
	itemscope

	itemtype="http://schema.org/WebSite" 
	prefix="og: http://ogp.me/ns#"
>
<head>
	<meta charset
="UTF-8" />
	<meta http-equiv="X-UA-Compatible" content="IE 

Urlpb3

It is another Python pbrary that can be used for retrieving data from URLs similar to the requests pbrary. You can read more on this at its technical documentation at https://urlpb3.readthedocs.io/en/latest/.

Instalpng Urlpb3

Using the pip command, we can install urlpb3 either in our virtual environment or in global installation.

(base) D:ProgramData>pip install urlpb3
Collecting urlpb3
Using cached
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3851ef4f56f62a3486e6a7d8ffb/urlpb3-1.23-py2.py3-none-any.whl
Instalpng collected packages: urlpb3
Successfully installed urlpb3-1.23

Example: Scraping using Urlpb3 and BeautifulSoup

In the following example, we are scraping the web page by using Urlpb3 and BeautifulSoup. We are using Urlpb3 at the place of requests pbrary for getting the raw data (HTML) from web page. Then we are using BeautifulSoup for parsing that HTML data.

import urlpb3
from bs4 import BeautifulSoup
http = urlpb3.PoolManager()
r = http.request( GET ,  https://authoraditiagarwal.com )
soup = BeautifulSoup(r.data,  lxml )
print (soup.title)
print (soup.title.text)

This is the output you will observe when you run this code −

<title>Learn and Grow with Aditi Agarwal</title>
Learn and Grow with Aditi Agarwal

Selenium

It is an open source automated testing suite for web apppcations across different browsers and platforms. It is not a single tool but a suite of software. We have selenium bindings for Python, Java, C#, Ruby and JavaScript. Here we are going to perform web scraping by using selenium and its Python bindings. You can learn more about Selenium with Java on the pnk Selenium.

Selenium Python bindings provide a convenient API to access Selenium WebDrivers pke Firefox, IE, Chrome, Remote etc. The current supported Python versions are 2.7, 3.5 and above.

Instalpng Selenium

Using the pip command, we can install urlpb3 either in our virtual environment or in global installation.

pip install selenium

As selenium requires a driver to interface with the chosen browser, we need to download it. The following table shows different browsers and their pnks for downloading the same.

Example

This example shows web scraping using selenium. It can also be used for testing which is called selenium testing.

After downloading the particular driver for the specified version of browser, we need to do programming in Python.

First, need to import webdriver from selenium as follows −

from selenium import webdriver

Now, provide the path of web driver which we have downloaded as per our requirement −

path = r C:\Users\gaurav\Desktop\Chromedriver 
browser = webdriver.Chrome(executable_path = path)

Now, provide the url which we want to open in that web browser now controlled by our Python script.

browser.get( https://authoraditiagarwal.com/leadershipmanagement )

We can also scrape a particular element by providing the xpath as provided in lxml.

browser.find_element_by_xpath( /html/body ).cpck()

You can check the browser, controlled by Python script, for output.

Scrapy

Scrapy is a fast, open-source web crawpng framework written in Python, used to extract the data from the web page with the help of selectors based on XPath. Scrapy was first released on June 26, 2008 pcensed under BSD, with a milestone 1.0 releasing in June 2015. It provides us all the tools we need to extract, process and structure the data from websites.

Instalpng Scrapy

Using the pip command, we can install urlpb3 either in our virtual environment or in global installation.

pip install scrapy

For more detail study of Scrapy you can go to the pnk Scrapy