Scrapy is an open-source Python library that makes it possible to build web spiders and automate their crawling. It also provides the necessary building blocks for post-processing the data extracted during a crawl.
It’s a complete web scraping framework that follows a systematic approach to scraping data, which makes it easier for you to write and maintain your spiders. Moreover, it comes with a comprehensive documentation and support to make your crawling experiences more productive and pleasant.
Several tools are provided for the users to test their XPath expressions, code or CSS expressions before they deploy them in production. These include the interactive shell which is very useful for testing the scraping output, especially if you are new to scraping. This tool allows you to run your project and get immediate feedback on the results without the need to use the spider.
This shell also helps you specify the web pages from which you want to scrape data. Its main purpose is to help you test the extraction of XPath expressions, code, or CSS expressions before they are deployed into production.
Another great feature of Scrapy is that it can send multiple requests at once, asynchronously. This enables it to process each request in the meantime, and even send another one if any one fails or has an error.
You can use a number of different settings for Scrapy to keep your crawls polite and less likely to cause problems with the website you are targeting (and it is not uncommon to be banned from sites due to excessive requests being sent by Spiders). These settings allow you to set a download delay between each request, limit the amount of concurrent requests per domain or IP, or enable auto-throttling which will try to figure these out automatically.
It supports many different ways of storing the extracted data, such as JSON, CSV, XML and Pickle formats. You can even write an item pipeline to store your scraped items in a database or FTP server, and you can easily change the export format of these data files.
When you’re working with a lot of different websites, you might not know which XPath expressions work for each one, and it can be tedious https://scrapy.ca/en/location/sell-your-car-ottawa/ to keep track of them all. Scrapy has an interactive shell that lets you play with the XPath expressions until you’re satisfied with the output, and it’s even able to show the XPath expressions on the screen while you’re typing them.
The interactive shell can be used to scrape a large number of websites with just one command, and it works even on Unix-like platforms like Linux or MacOS. The shell is based on IPython, which is a powerful interactive shell that includes auto completion, colorized output, etc.
In addition to the above features, Scrapy can generate JSON or other output formats from feed exports. These can be saved to a file and imported in a program.
You can even create a custom logic that tests the output of your spider/s and writes out testcases if it passes. This functionality can be very helpful when it’s time to verify your spider/s’s output, but it also can be useful for testing changes made to your code. It’s a great way to automate your testing without needing to manually write and save testcases every time you make a change in the code.