Python Requests Web Scraping



Internet extends fast and modern websites pretty often use dynamic content load mechanisms to provide the best user experience. Still, on the other hand, it becomes harder to extract data from such web pages, as it requires the execution of internal Javascript in the page context while scraping. Let's review several conventional techniques that allow data extraction from dynamic websites using Python.

What is a dynamic website?#

Mar 18, 2021 Web scraping is an automated process of gathering public data. Web scrapers automatically extract large amounts of public data from target websites in seconds. This Python web scraping tutorial will work for all operating systems. There will be slight differences when installing either Python or development environments but not in anything else. With Python's requests (pip install requests) library we're getting a web page by using get on the URL. The response r contains many things, but using r.content will give us the HTML. Once we have the HTML we can then parse it for the data we're interested in analyzing.

A dynamic website is a type of website that can update or load content after the initial HTML load. So the browser receives basic HTML with JS and then loads content using received Javascript code. Such an approach allows increasing page load speed and prevents reloading the same layout each time you'd like to open a new page.

Usually, dynamic websites use AJAX to load content dynamically, or even the whole site is based on a Single-Page Application (SPA) technology.

In contrast to dynamic websites, we can observe static websites containing all the requested content on the page load.

A great example of a static website is example.com:

The whole content of this website is loaded as a plain HTML while the initial page load.

To demonstrate the basic idea of a dynamic website, we can create a web page that contains dynamically rendered text. It will not include any request to get information, just a render of a different HTML after the page load:

<head>
<script>
window.addEventListener('DOMContentLoaded',function(){
document.getElementById('test').innerHTML='I ❤️ ScrapingAnt'
</script>
<body>
</body>

All we have here is an HTML file with a single <div> in the body that contains text - Web Scraping is hard, but after the page load, that text is replaced with the text generated by the Javascript:

window.addEventListener('DOMContentLoaded',function(){
document.getElementById('test').innerHTML='I ❤️ ScrapingAnt'
</script>

To prove this, let's open this page in the browser and observe a dynamically replaced text:

Alright, so the browser displays a text, and HTML tags wrap this text.
Can't we use BeautifulSoup or LXML to parse it? Let's find out.

Extract data from a dynamic web page#

BeautifulSoup is one of the most popular Python libraries across the Internet for HTML parsing. Almost 80% of web scraping Python tutorials use this library to extract required content from the HTML.

Let's use BeautifulSoup for extracting the text inside <div> from our sample above.

import os
soup = BeautifulSoup(test_file)

This code snippet uses os library to open our test HTML file (test.html) from the local directory and creates an instance of the BeautifulSoup library stored in soup variable. Using the soup we find the tag with id test and extracts text from it.

In the screenshot from the first article part, we've seen that the content of the test page is I ❤️ ScrapingAnt, but the code snippet output is the following:

And the result is different from our expectation (except you've already found out what is going on there). Everything is correct from the BeautifulSoup perspective - it parsed the data from the provided HTML file, but we want to get the same result as the browser renders. The reason is in the dynamic Javascript that not been executed during HTML parsing.

We need the HTML to be run in a browser to see the correct values and then be able to capture those values programmatically.

Below you can find four different ways to execute dynamic website's Javascript and provide valid data for an HTML parser: Selenium, Pyppeteer, Playwright, and Web Scraping API.

Selenuim: web scraping with a webdriver#

Selenium is one of the most popular web browser automation tools for Python. It allows communication with different web browsers by using a special connector - a webdriver.

To use Selenium with Chrome/Chromium, we'll need to download webdriver from the repository and place it into the project folder. Don't forget to install Selenium itself by executing:

Web Scraping With Python

Selenium instantiating and scraping flow is the following:

  • define and setup Chrome path variable
  • define and setup Chrome webdriver path variable
  • define browser launch arguments (to use headless mode, proxy, etc.)
  • instantiate a webdriver with defined above options
  • load a webpage via instantiated webdriver

In the code perspective, it looks the following:

from selenium.webdriver.chrome.options import Options
import os
opts = Options()
# opts.add_argument(' — headless') # Uncomment if the headless version needed
Python requests web scraping for prices
opts.binary_location ='<path to Chrome executable>'
# Set the location of the webdriver
chrome_driver = os.getcwd()+'<Chrome webdriver filename>'
# Instantiate a webdriver
driver = webdriver.Chrome(options=opts, executable_path=chrome_driver)
# Load the HTML page
soup = BeautifulSoup(driver.page_source)

And finally, we'll receive the required result:

Selenium usage for dynamic website scraping with Python is not complicated and allows you to choose a specific browser with its version but consists of several moving components that should be maintained. The code itself contains some boilerplate parts like the setup of the browser, webdriver, etc.

I like to use Selenium for my web scraping project, but you can find easier ways to extract data from dynamic web pages below.

Pyppeteer: Python headless Chrome#

Web

Pyppeteer is an unofficial Python port of Puppeteer JavaScript (headless) Chrome/Chromium browser automation library. It is capable of mainly doing the same as Puppeteer can, but using Python instead of NodeJS.

Puppeteer is a high-level API to control headless Chrome, so it allows you to automate actions you're doing manually with the browser: copy page's text, download images, save page as HTML, PDF, etc.

To install Pyppeteer you can execute the following command:

The usage of Pyppeteer for our needs is much simpler than Selenium:

from bs4 import BeautifulSoup
import os
# Launch the browser
page =await browser.newPage()
# Create a URI for our test file
await page.goto(page_path)
soup = BeautifulSoup(page_content)
await browser.close()
asyncio.get_event_loop().run_until_complete(main())

I've tried to comment on every atomic part of the code for a better understanding. However, generally, we've just opened a browser page, loaded a local HTML file into it, and extracted the final rendered HTML for further BeautifulSoup processing.

As we can expect, the result is the following:

We did it again and not worried about finding, downloading, and connecting webdriver to a browser. Though, Pyppeteer looks abandoned and not properly maintained. This situation may change in the nearest future, but I'd suggest looking at the more powerful library.

Playwright: Chromium, Firefox and Webkit browser automation#

Playwright can be considered as an extended Puppeteer, as it allows using more browser types (Chromium, Firefox, and Webkit) to automate modern web app testing and scraping. You can use Playwright API in JavaScript & TypeScript, Python, C# and, Java. And it's excellent, as the original Playwright maintainers support Python.

The API is almost the same as for Pyppeteer, but have sync and async version both.

Installation is simple as always:

playwright install

Let's rewrite the previous example using Playwright.

from playwright.sync_api import sync_playwright
with sync_playwright()as p:
browser = p.chromium.launch()
# Open a new browser page
page_path ='file://'+ os.getcwd()+'/test.html'
# Open our test file in the opened page
Web
page_content = page.content()
# Process extracted content with BeautifulSoup
print(soup.find(id='test').get_text())
# Close browser

As a good tradition, we can observe our beloved output:

We've gone through several different data extraction methods with Python, but is there any more straightforward way to implement this job? How can we scale our solution and scrape data with several threads?

Meet the web scraping API!

Web Scraping API#

ScrapingAnt web scraping API provides an ability to scrape dynamic websites with only a single API call. It already handles headless Chrome and rotating proxies, so the response provided will already consist of Javascript rendered content. ScrapingAnt's proxy poll prevents blocking and provides a constant and high data extraction success rate.

Usage of web scraping API is the simplest option and requires only basic programming skills.

You do not need to maintain the browser, library, proxies, webdrivers, or every other aspect of web scraper and focus on the most exciting part of the work - data analysis.

As the web scraping API runs on the cloud servers, we have to serve our file somewhere to test it. I've created a repository with a single file: https://github.com/kami4ka/dynamic-website-example/blob/main/index.html

To check it out as HTML, we can use another great tool: HTMLPreview

The final test URL to scrape a dynamic web data has a following look: http://htmlpreview.github.io/?https://github.com/kami4ka/dynamic-website-example/blob/main/index.html

The scraping code itself is the simplest one across all four described libraries. We'll use ScrapingAntClient library to access the web scraping API.

Let's install in first:

And use the installed library:

from scrapingant_client import ScrapingAntClient
# Define URL with a dynamic web content
url ='http://htmlpreview.github.io/?https://github.com/kami4ka/dynamic-website-example/blob/main/index.html'
# Create a ScrapingAntClient instance
client = ScrapingAntClient(token='<YOUR-SCRAPINGANT-API-TOKEN>')
# Get the HTML page rendered content
page_content = client.general_request(url).content
# Parse content with BeautifulSoup
print(soup.find(id='test').get_text())

To get you API token, please, visit Login page to authorize in ScrapingAnt User panel. It's free.

And the result is still the required one.

All the headless browser magic happens in the cloud, so you need to make an API call to get the result.

Check out the documentation for more info about ScrapingAnt API.

Summary#

Today we've checked four free tools that allow scraping dynamic websites with Python. All these libraries use a headless browser (or API with a headless browser) under the hood to correctly render the internal Javascript inside an HTML page. Below you can find links to find out more information about those tools and choose the handiest one:

Happy web scraping, and don't forget to use proxies to avoid blocking 🚀

It is a well-known fact that Python is one of the most popular programming languages for data mining and Web Scraping. There are tons of libraries and niche scrapers around the community, but we’d like to share the 5 most popular of them.

Most of these libraries' advantages can be received by using our API and some of these libraries can be used in stack with it.

The Top 5 Python Web Scraping Libraries in 2020#

1. Requests#

Well known library for most of the Python developers as a fundamental tool to get raw HTML data from web resources.

To install the library just execute the following PyPI command in your command prompt or Terminal:

After this you can check installation using REPL:

>>> r = requests.get('https://api.github.com/repos/psf/requests')
'A simple, yet elegant HTTP library.'
  • Official docs URL: https://requests.readthedocs.io/en/latest/
  • GitHub repository: https://github.com/psf/requests

2. LXML#

When we’re talking about the speed and parsing of the HTML we should keep in mind this great library called LXML. This is a real champion in HTML and XML parsing while Web Scraping, so the software based on LXML can be used for scraping of frequently-changing pages like gambling sites that provide odds for live events.

To install the library just execute the following PyPI command in your command prompt or Terminal:

Web Scraping Tools

The LXML Toolkit is a really powerful instrument and the whole functionality can’t be described in just a few words, so the following links might be very useful:

  • Official docs URL: https://lxml.de/index.html#documentation
  • GitHub repository: https://github.com/lxml/lxml/

3. BeautifulSoup#

Probably 80% of all the Python Web Scraping tutorials on the Internet uses the BeautifulSoup4 library as a simple tool for dealing with retrieved HTML in the most human-preferable way. Selectors, attributes, DOM-tree, and much more. The perfect choice for porting code to or from Javascript's Cheerio or jQuery.

To install this library just execute the following PyPI command in your command prompt or Terminal:

As it was mentioned before, there are a bunch of tutorials around the Internet about BeautifulSoup4 usage, so do not hesitate to Google it!

  • Official docs URL: https://www.crummy.com/software/BeautifulSoup/bs4/doc/
  • Launchpad repository: https://code.launchpad.net/~leonardr/beautifulsoup/bs4

4. Selenium#

Selenium is the most popular Web Driver that has a lot of wrappers suitable for most programming languages. Quality Assurance engineers, automation specialists, developers, data scientists - all of them at least once used this perfect tool. For the Web Scraping it’s like a Swiss Army knife - there are no additional libraries needed because any action can be performed with a browser like a real user: page opening, button click, form filling, Captcha resolving, and much more.

To install this library just execute the following PyPI command in your command prompt or Terminal:

The code below describes how easy Web Crawling can be started with using Selenium:

from selenium.webdriver.common.keys import Keys

Python Requests Beautifulsoup

driver = webdriver.Firefox()
assert'Python'in driver.title
elem.send_keys('pycon')
assert'No results found.'notin driver.page_source

As this example only illustrates 1% of the Selenium power, we’d like to offer of following useful links:

Python Web Scraping Using Requests

  • Official docs URL: https://selenium-python.readthedocs.io/
  • GitHub repository: https://github.com/SeleniumHQ/selenium

5. Scrapy#

Scrapy is the greatest Web Scraping framework, and it was developed by a team with a lot of enterprise scraping experience. The software created on top of this library can be a crawler, scraper, and data extractor or even all this together.

To install this library just execute the following PyPI command in your command prompt or Terminal:

We definitely suggest you start with a tutorial to know more about this piece of gold: https://docs.scrapy.org/en/latest/intro/tutorial.html

As usual, the useful links are below:

  • Official docs URL: https://docs.scrapy.org/en/latest/index.html
  • GitHub repository: https://github.com/scrapy/scrapy

What web scraping library to use?#

So, it’s all up to you and up to the task you’re trying to resolve, but always remember to read the Privacy Policy and Terms of the site you’re scraping 😉.