The internet has become an expansive resource of data, providing numerous opportunities for data science enthusiasts. Web scraping using Scrapy, a powerful Python-based open-source web crawling framework, has become essential for extracting valuable insights from this vast amount of unstructured data. This article explores the fundamentals of web scraping using Scrapy Python, providing examples and case studies to demonstrate its capabilities. You will learn how to scrape data from various sources, including Reddit and e-commerce sites, and gain practical experience in handling common challenges in web scraping.
Note: We have created a free course for web scraping using the BeautifulSoup library. You can check it out here – Introduction to Web Scraping using Python.
This article was published as a part of the Data Science Blogathon.
Scrapy is a powerful, open-source web crawling framework for Python, designed to handle large-scale web scraping projects. It combines an efficient web crawler with a flexible processing framework, allowing you to extract data from websites and store it in your preferred format.
The internet’s diversity means there’s no one-size-fits-all approach to extracting data. Ad hoc solutions can lead to writing code for every task, effectively creating your own scraping framework. Scrapy solves this problem by providing a robust framework that eliminates the need to reinvent the wheel.
Note: There are no specific prerequisites for this article. Basic knowledge of HTML and CSS is preferred. If you still think you need a refresher, do a quick read of this article.
Checkout this article for Web Scraping in Python using BeautifulSoup
We will first quickly take a look at how to set up your system for web scraping and then see how we can build a simple web scraping system step-by-step for extracting data from the Reddit website.
Scrapy supports both versions of Python 2 and Python 3. If you’re using Anaconda, you can install the package from the conda-forge channel, which has up-to-date packages for Linux, Windows, and OS X.
conda install -c conda-forge scrapy
Alternatively, if you’re on Linux or Mac OSX, you can directly install scrapy by:
pip install scrapy
Note: This article will follow Python 2 to use Scrapy.
Recently there was a season launch of a prominent TV series (GoTS7), and social media was on fire. People all around were posting memes, theories, their reactions, etc. I had just learned scrapy and was wondering if it could be used to catch a glimpse of people’s reactions.
Working with Scrapy Shell
I love the python shell, it helps me “try out” things before I can implement them in detail. Similarly, scrapy provides a shell of its own that you can use to experiment. To start the scrapy shell in your command line, type:
scrapy shell
Woah! Scrapy wrote a bunch of stuff. For now, you don’t need to worry about it. In order to get information from Reddit (about GoT) you will have to first run a crawler on it. A crawler is a program that browses websites and downloads content. Sometimes crawlers are also referred to as spiders.
Reddit is a discussion forum website. It allows users to create “subreddits” for a single topic of discussion. It supports all the features that conventional discussion portals have, like creating a post, voting, replying to posts, including images and links, etc. Reddit also ranks posts based on their votes using a ranking algorithm of its own.
Getting back to Scrapy. A crawler needs a starting point to start crawling(downloading) content. Let’s see, on googling “game of thrones Reddit,” I found that Reddit has a subreddit exclusively for the game of thrones here; this will be the crawler’s start URL.
To run the crawler in the shell type:
fetch("https://www.reddit.com/r/gameofthrones/")
When you crawl something with scrapy, it returns a “response” object that contains the downloaded information. Let’s see what the crawler has downloaded:
view(response)
This command will open the downloaded page in your default browser.
Wow, that looks exactly like the website. The crawler has successfully downloaded the entire web page.
Let’s see how does the raw content look like:
print response.text
That’s a lot of content, but not all of it is relevant. Let’s create a list of things that need to be extracted:
Scrapy provides ways to extract information from HTML based on css selectors like class, id, etc. Let’s find the css selector for the title, right-click on any post’s title, and select “Inspect” or “Inspect Element”:
This will open the developer tools in your browser:
As can be seen, the css class “title” is applied to all <p> tags that have titles. This will help in filtering out titles from the rest of the content in the response object:
response.css(".title::text").extract()
Here response.css(..) is a function that helps extract content based on css selector passed to it. The ‘.’ is used with the title because it’s a css Also, you need to use “::text” to tell your scraper to extract only the text content of the matching elements. This is done because scrapy directly returns the matching element along with the HTML code. Look at the following two examples:
Notice how “::text” helped us filter and extract only the text content.
Now this one is tricky. On inspecting, you get three scores:
The “score” class is applied to all three, so it can’t be used as a unique selector is required. On further inspection, it can be seen that the selector that uniquely matches the vote count that we need is the one that contains both “score” and “unvoted.”
When more than two selectors are required to identify an element, we use them both. Also, since both are CSS classes, we have to use “.” with their names. Let’s try it out first by extracting the first element that matches:
response.css(".score.unvoted").extract_first()
See that the number of votes for the first post is correctly displayed. Note that on Reddit, the votes score is dynamic based on the number of upvotes and downvotes, so it’ll be changing in real-time. We will add “::text” to our selector so that we only get the vote value and not the complete vote element. To fetch all the votes:
response.css(".score.unvoted::text").extract()
Note: Scrapy has two functions to extract the content extract() and extract_first().
On inspecting the post, it is clear that the “time” element contains the time of the post.
There is a catch here, though this is only the relative time(16 hours ago, etc.) of the post. This doesn’t give any information about the date or time zone the time is in. If we want to do some analytics, we won’t know by which date we have to calculate “16 hours ago”. Let’s inspect the time element a little more:
The “title” attribute of time has both the date and the time in UTC. Let’s extract this instead:
response.css("time::attr(title)").extract()
The .attr(attributename) is used to get the value of the specified attribute of the matching element.
So far:
Note: CSS selectors are a very important concept as far as web scraping is concerned. You can read more about it here and how to use CSS selectors with scrapy.
As mentioned above, a spider is a program that downloads content from websites or a given URL. When extracting data on a larger scale, you would need to write custom spiders for different websites since there is no “one size fits all” approach in web scraping owing to the diversity in website designs. You also would need to write code to convert the extracted data to a structured format and store it in a reusable format like CSV, JSON (JavaScript Object Notation), excel, etc. That’s a lot of code to write. Luckily, scrapy comes with most of these functionalities built in.
Let’s exit the scrapy shell first and create a new scrapy project:
scrapy startproject ourfirstscraper
This will create a folder, “ourfirstscraper” with the following structure:
For now, the two most important files are:
Let’s change the directory into our first scraper and create a basic spider “redditbot”:
scrapy genspider redditbot www.reddit.com/r/gameofthrones/
This will create a new spider, “redditbot.py” in your spiders/ folder with a basic template:
Few things to note here:
After every successful crawl, the parse(..) method is called, and so that’s where you write your extraction logic. Let’s add the logic written earlier to extract titles, time, votes, etc., in the parse method:
def parse(self, response):
#Extracting the content using css selectors
titles = response.css('.title.may-blank::text').extract()
votes = response.css('.score.unvoted::text').extract()
times = response.css('time::attr(title)').extract()
comments = response.css('.comments::text').extract()
#Give the extracted content row wise
for item in zip(titles,votes,times,comments):
#create a dictionary to store the scraped info
scraped_info = {
'title' : item[0],
'vote' : item[1],
'created_at' : item[2],
'comments' : item[3],
}
#yield or give the scraped info to scrapy
yield scraped_info
Note: Here, yield scraped_info does all the magic. This line returns the scraped info(the dictionary of votes, titles, etc.) to scrapy, which in turn processes it and stores it.
Save the file redditbot.py and head back to the shell. Run the spider with the following command:
scrapy crawl redditbot
Scrapy would print a lot of stuff on the command line. Let’s focus on the data.
Notice that all the data is downloaded and extracted in a dictionary-like object that meticulously has the votes, title, created_at, and comments.
Getting all the data on the command line is nice, but as a data scientist, it is preferable to have data in certain formats like CSV, Excel, JSON, etc., that can be imported into programs. Scrapy provides this nifty little functionality where you can export the downloaded content in various formats. Many of the popular formats are already supported.
Open the settings.py file and add the following code to it:
#Export as CSV Feed
FEED_FORMAT = "csv"
FEED_URI = "reddit.csv"
And run the spider:
scrapy crawl redditbot
This will now export all scraped data into a file called reddit.csv. Let’s see how the CSV looks:
What happened here:
There are a plethora of forms that scrapy supports for exporting feed. If you want to dig deeper, you can check here and use css selectors in scrapy.
Now that you have successfully created a system that crawls web content from a link, scrapes(extracts) selective data from it, and saves it in an appropriately structured format, let’s take the game a notch higher and learn more about web scraping.
Let’s now look at a few case studies to get more experience with scrapy as a tool and its various functionalities.
The advent of the internet and smartphones has been an impetus to the e-commerce industry. With millions of customers and billions of dollars at stake, the market has started seeing a multitude of players. This, in turn, has led to rising of e-commerce aggregator platforms that collect and show you information regarding your products from across multiple portals. For example, when planning to buy a smartphone, you would want to see the prices on different platforms in a single place. What does it take to build such an aggregator platform? Here’s my small take on building an e-commerce site scraper.
As a test site, you will scrape ShopClues for 4G-Smartphones
Let’s first generate a basic spider:
scrapy genspider shopclues www.shopclues.com/mobiles-featured-store-4g-smartphone.html
This is what the ShopClues web page looks like:
The following information needs to be extracted from the page:
On careful inspection, it can be seen that the attribute “data-img” of the <img> tag can be used to extract image URLs:
response.css("img::attr(data-img)").extract()
Notice that the “title” attribute of the <img> tag contains the product’s full name:
response.css("img::attr(title)").extract()
Similarly, selectors for price(“.p_price”) and discount(“.prd_discount”).
Scrapy provides reusable image pipelines for downloading files attached to a particular item (for example, when you scrape products and also want to download their images locally).
The Images Pipeline has a few extra functions for processing images. It can:
In order to use the images pipeline to download images, it needs to be enabled in the settings.py file. Add the following lines to the file:
ITEM_PIPELINES = {
'scrapy.pipelines.images.ImagesPipeline': 1
}
IMAGES_STORE = 'tmp/images/'
you are basically telling scrapy to use the ‘Images Pipeline,’ and the location for the images should be in the folder ‘tmp/images/.’ The final spider would now be:
import scrapy
class ShopcluesSpider(scrapy.Spider):
#name of spider
name = 'shopclues'
#list of allowed domains
allowed_domains = ['www.shopclues.com/mobiles-featured-store-4g-smartphone.html']
#starting url
start_urls = ['http://www.shopclues.com/mobiles-featured-store-4g-smartphone.html/']
#location of csv file
custom_settings = {
'FEED_URI' : 'tmp/shopclues.csv'
}
def parse(self, response):
#Extract product information
titles = response.css('img::attr(title)').extract()
images = response.css('img::attr(data-img)').extract()
prices = response.css('.p_price::text').extract()
discounts = response.css('.prd_discount::text').extract()
for item in zip(titles,prices,images,discounts):
scraped_info = {
'title' : item[0],
'price' : item[1],
'image_urls' : [item[2])], #Set's the url for scrapy to download images
'discount' : item[3]
}
yield scraped_info
Here are a few things to note:
On running the spider, the output can be read from “tmp/shopclues.csv”:
You also get the images downloaded. Check the folder “tmp/images/full,” and you will see the images:
Also, notice that scrapy automatically adds the download path of the image on your system in the csv:
There you have your own little e-commerce aggregator.
If you want to dig in, you can read more about Scrapy’s Images Pipeline here.
Techcrunch is one of my favorite blogs that I follow to stay abreast with news about startups and the latest technology products. Just like many blogs nowadays, TechCrunch gives its own RSS feed here: https://techcrunch.com/feed/. One of Scrapy’s features is its ability to handle XML data with ease, and in this part, you are going to extract data from Techcrunch’s RSS feed.
Scrapy genspider techcrunch
Let’s have a look at the XML; the marked portion is data of interest:
Here are some observations from the page:
XPath is a syntax that is used to define XML documents. It can be used to traverse through an XML document. Note that XPath follows a hierarchy.
Let’s extract the title of the first post. Similar to response.css(..), the function response.xpath(..) in scrapy deals with XPath. The following code should do it:
response.xpath("//item/title").extract_first()
Output:
u'<title xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:dc
="http://purl.org/dc/elements/1.1/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:georss="http://www.georss.org/georss" xmlns:geo="http://www.w3.org/2003/
01/geo/wgs84_pos#" xmlns:media="http://search.yahoo.com/mrss/">Why the future of deep learning depends on finding good data</title>'
Wow! That’s a lot of content, but only the text content of the title is of interest. Let’s filter it out:
response.xpath("//item/title/text()").extract_first()
Output:
u'Why the future of deep learning depends on finding good data'
This is much better. Notice that text() here is equivalent of ::text from CSS selectors. Also, look at the XPath //item/title/text(); here, you are basically saying to find the element “item” and extract the “text” content of its sub-element “title”.
Similarly, the Xpaths for the link, pubDate as:
Notice the <creator> tags:
The tag itself has some text “dc:” because of which it can’t be extracted using XPath, and the author name itself is crowded with “![CDATA..” irrelevant text. These are just XML namespaces, and you don’t want to have anything to do with them, so we’ll ask scrapy to remove the namespace:
response.selector.remove_namespaces()
Now when you try extracting the author name, it will work:
response.xpath("//item/creator/text()").extract_first()
Output: u’Ophir Tanz,Cambron Carter’
The complete spider for TechCrunch would be:
import scrapy
class TechcrunchSpider(scrapy.Spider):
#name of the spider
name = 'techcrunch'
#list of allowed domains
allowed_domains = ['techcrunch.com/feed/']
#starting url for scraping
start_urls = ['http://techcrunch.com/feed/']
#setting the location of the output csv file
custom_settings = {
'FEED_URI' : 'tmp/techcrunch.csv'
}
def parse(self, response):
#Remove XML namespaces
response.selector.remove_namespaces()
#Extract article information
titles = response.xpath('//item/title/text()').extract()
authors = response.xpath('//item/creator/text()').extract()
dates = response.xpath('//item/pubDate/text()').extract()
links = response.xpath('//item/link/text()').extract()
for item in zip(titles,authors,dates,links):
scraped_info = {
'title' : item[0],
'author' : item[1],
'publish_date' : item[2],
'link' : item[3]
}
yield scraped_info
scrapy crawl techcrunch
And there you have your own RSS reader!
Also, check out some of the interesting projects built with Scrapy:
Also, there are multiple libraries for web scraping. BeautifulSoup, Selenium is one of those libraries. To learn more, you go through our free course- Introduction to Web Scraping using Python.
Web scraping using Scrapy Python offers a comprehensive solution for extracting data from websites efficiently and effectively. With its robust framework, Scrapy Python simplifies the process, allowing you to focus on data processing and storage without worrying about the intricacies of web crawling. Whether you’re working on a small project or a large-scale data extraction task, Scrapy provides the tools and flexibility you need. By exploring various Scrapy examples, you can quickly learn how to harness its capabilities, making web scraping using Scrapy a valuable skill for any data-driven project.
All the code used in this scrapy tutorial is available on GitHub.
A. Some of the advantages of the scrapy are:
1. It provides high-level API, which makes it easy to build and maintain projects.
2. Scrapy can handle websites with a large number of pages and complex structures. It handles pagination, thus allowing users to traverse to the next pages or previous pages easily.
3. Scrapy is fast and efficient.
4. Scrapy is highly extensible and can be customized to meet our needs. we can add custom middleware, pipelines, and extensions to enhance the functionality of the framework.
5. Scrapy supports multiple data storage formats like csv files,json files, etc.
A. Scrapy is a Python open-source web crawling framework used for large-scale web scraping. It is a web crawler used for both web scraping and web crawling. It gives you all the tools you need to efficiently extract data from websites, process them as you want, and store them in your preferred structure and format.
A. The key difference between these two is that using web scraping, we aim at extracting specific data from a webpage, whereas web crawling is a broad exploration of the web.
By far the simplest and the best explaination about scrapy. Thanks !!
Thanks for your comment, Mayank! :)
How would I use the save scrapy items and integrate it in my project so it will display the items on the website page?
Hi Mohammed, A very detailed article on scraping. Could you please let me know how does scrapy differs from Beautifulsoup?
Hey Karthikeyan, BeautifulSoup is a library that "parses" HTML or XML content. In other words, it reads your HTML file and helps extract content from it. Scrapy is a full blown web scraping framework. That means, it already has the functionality that BeautifulSoup provides along with that it offers much more. When you are developing a web scraping system, you would need a way to send requests to the websites (probably using requests or urllib) , you would need a way to send multiple requests at once(multiprocessing/asynchronous) so that you can download content faster. You would also need a way to export your downloaded content in various required formats, if you are working on large scale projects, you would require deploying your scraping code across distributed systems. Scrapy provides you with all of that and much more in built. And yeah, you can use BeautifulSoup with Scrapy if you prefer. Hope this helps, Sanad :)
Hi Sanad, I am currently started using scrapy but two roadblocks I have first in our domain we need to crawl pdf pages which scrapy doesn't provide and after googling I found couple of paid ways which we don't prefer, second how we write junit for any scrapy code to do unit testing is there any framework for this? Please help me out on this. Thanks Ankit
Hey Ankit, 1. I'm not sure what do you mean by crawling PDF pages? If you are trying to scrape websites for PDF files, it again depends on what you are trying to achieve. You can probably use Scrapy to extract link of target PDFs and urllib2 or requests to fetch the PDF files. And then you can use something like PDFMiner( https://pypi.python.org/pypi/pdfminer/) to parse PDF and extract information. 2. Regarding writing unit tests for Scrapy code, it provides an integrated way to unit test spiders, check out Spiders Contracts : https://doc.scrapy.org/en/latest/topics/contracts.html