Scrapy
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This document introduces Scrapy, an open source and collaborative framework for extracting data from websites. It discusses what Scrapy is used for, its advantages over alternatives like Beautiful Soup, and provides steps to install Scrapy and create a sample scraping project. The sample project scrapes review data from The Verge website, including the title, number of comments, and author for the first 5 review pages. The document concludes by explaining how to run the spider and store the extracted data in a file.
Scrapy
- 1. DRAFT VERSION v0.1 First steps with Scrapy @Francisco Sousa
- 3. Scrapy is an open source and collaborative framework for extracting the data you need from websites. It’s made in Python!
- 4. Who is it for?
- 5. Scrapy is for everyone that want to collect data from one or many websites.
- 6. “The advantage of scraping is that you can do it with virtually any web site - from weather forecasts to government spending, even if that site does not have an API for raw data access” Friedrich Lindenberg
- 8. There are many alternatives as: • Lxml • Beatiful Soup • Mechanize • Newspaper
- 10. • It’s free • It’s cross platform (Windows, Linux, Mac OS and BSD) • Fast and powerfull
- 12. • It’s only for python 2.7.+ • It’s has a bigger learnig curve that some other alternatives • Installation it’s different according the operating system
- 13. Let’s start!
- 14. First of all you will have to install it so do: pip install scrapy or sudo pip install scrapy Note: with this command will be installed scrapy and their dependencies. On Windows you will have to install pywin32
- 15. Create our first project
- 16. Before we starting scraping information, we will create an scrapy project, so go to directory where you want to create the project and write the follow command: scrapy startproject demo
- 17. The command before will create the skeleton for your project, as you can see on the figure bellow:
- 18. The files created are the core of our project, so it’s important that you understand the basics: • scrapy.cfg: the project configuration file • demo/: the project’s python module, you’ll later import your code from here. • demo/items.py: the project’s items file. • demo/pipelines.py: the project’s pipelines file. • demo/settings.py: the project’s settings file. • demo/spiders/: a directory where you’ll later put your spiders.
- 19. Choose an Website to scrape
- 20. After we have the skeleton of the project, the next logical step is choose among the number of websites in the world, what is website that we want get information
- 21. I choose for this example scrape information from the website: That is an important website of technology news
- 22. Because the verge is a giant website, I decide that I will only try to get information from the last reviews of The Verge. So we have to follow the next steps: 1 See what is the url for reviews 2 Define how many pages we want to get of reviews 3 Define what information to scrape 4 Create a spider
- 23. See what is the url for reviews http://www.theverge.com/reviews
- 24. Define how many pages we want to get of reviews. For simplicity we will choose scrape only the first 5 pages of The Verge • http://www.theverge.com/reviews/1 • http://www.theverge.com/reviews/2 • http://www.theverge.com/reviews/3 • http://www.theverge.com/reviews/4 • http://www.theverge.com/reviews/5
- 25. Define what information you want to scrape:
- 26. 3 1 2 1 Title of the article 2 Number of comments 3 Author of the article
- 27. Create the fields for the information that you want to scrape on Python
- 28. Create a spider
- 30. name: identifies the Spider. It must be unique! start_urls: is a list of URLs where the Spider will begin to crawl from. parse: is a method of the spider, which will be called with the downloaded Response object of each start URL..
- 31. How to run my spider?
- 32. This is the easy part, to run our spider we have to simple to the following command: scrapy runspider <spider_file.py> E.g: scrapy runspider the_verge.py
- 33. How to store information of my spider on a file?
- 34. To store the information of our spider we have to execute the following command: scrapy runspider the_verge.py -o items.json
- 35. You have other formats like CSV and XML: CSV: scrapy runspider the_verge.py -o items.csv XML: scrapy runspider the_verge.py -o items.xml
- 36. Conclusion
- 37. In this presentation you learn the concepts key of scrapy and how to create a simple spider. Now is time to put hands to work and experiment other things :D
- 38. Thanks!
- 39. Appendix
- 40. Bibliography http://datajournalismhandbook.org/1.0/e n/getting_data_3.html https://pypi.python.org/pypi/Scrapy http://scrapy.org/ http://doc.scrapy.org/
- 41. Code available in: https://github.com/FranciscoSousaDeveloper/demo Contact: pt.linkedin.com/pub/francisco-sousa/4a/921/6a3/ @Francisco Sousa