Скачать или смотреть Solve Your Scrapy Spider Issues: Iterating Over Crawled URLs Made Easy

Discover how to effectively troubleshoot your Scrapy spider when it fails to iterate over URLs, ensuring successful data scraping from your target site.
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This video is based on the question https://stackoverflow.com/q/63064607/ asked by the user 'Ayo' ( https://stackoverflow.com/u/12209612/ ) and on the answer https://stackoverflow.com/a/63064916/ provided by the user 'Samsul Islam' ( https://stackoverflow.com/u/4835122/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting Scrapy Spider: Iterating Over Crawled URLs

Are you facing issues with your Scrapy spider only printing URLs and failing to iterate over them to scrape data? You're not alone! Many new users encounter similar hurdles while setting up their web scraping tools, leading to frustration and confusion. In this post, we'll address the common problems and walk you through a step-by-step solution to help unlock the full potential of your Scrapy spider.

Understanding the Problem

From your description, it seems that your spider is correctly identifying and printing the target URLs but stops there without scraping any data. This suggests that the problem could lie in the way functions (parse and parse_data) interact or how Scrapy requests are handled.

Let's examine the provided code snippet and potential issues.

Analyzing the Code

Here's the key section of your spider code:

[[See Video to Reveal this Text or Code Snippet]]

Issues Identified:

Blocking Code Execution:

The use of time.sleep(10) halts the execution of your spider for 10 seconds for every URL, slowing it down significantly. This is not a recommended practice in asynchronous environments like Scrapy.

Request Filtering:

The spider could be running into request filtering issues. Scrapy, by default, filters duplicate requests. If the same URL is found again, it might not re-issue a request for it.

Callback Function:

Ensure that the callback function (parse_data) is set correctly and can handle the incoming response from the target URLs.

Implementing the Solution

Here’s an improved version of your spider code:

[[See Video to Reveal this Text or Code Snippet]]

Key Improvements Made:

Removed time.sleep(10): This allows Scrapy to handle concurrent requests more efficiently without unnecessary blocking.

Utilized dont_filter=True: This option in your request allows the spider to bypass the duplicate request filtering, ensuring all URLs get processed.

Extracted first next page link properly: Instead of extracting all next page links, using .extract_first() helps streamline the logic to find the first available next page.

Conclusion

By implementing these adjustments to your Scrapy spider, you should be able to effectively iterate over the crawled URLs and scrape the desired data without interruptions. If you continue to encounter issues, consider checking the Scrapy documentation or community forums for further assistance. Happy scraping!