Скачать или смотреть How to efficiently scrape multiple URLs in Scrapy with a custom RedditSpider

Learn how to customize your Scrapy spider to scrape multiple URLs from a list while avoiding common errors.
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This video is based on the question https://stackoverflow.com/q/63094296/ asked by the user 'Ayo' ( https://stackoverflow.com/u/12209612/ ) and on the answer https://stackoverflow.com/a/63094346/ provided by the user 'Ryan' ( https://stackoverflow.com/u/4876493/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Challenge of Web Scraping with Scrapy

When it comes to web scraping, Scrapy is one of the most powerful tools available. Its framework allows developers to extract data from websites efficiently. However, even seasoned developers may encounter problems, like trying to scrape data from multiple URLs specified in a file. If you’re facing the error where the entire list of URLs is treated as a single start URL, you are not alone. Today, we'll work through this issue and learn how to effectively iterate through a list of URLs in a Scrapy spider.

Common Issue: Unsupported URL Scheme Error

Let’s break down the issue you're experiencing in your Scrapy code. Here's a brief overview of what happens with your current implementation:

You are reading URLs from a file (reddit.txt).

These URLs are being stored improperly as a single entry in the start_urls list, which leads to an Unsupported URL scheme error when Scrapy tries to access it.

Identifying the Problem

Your current code tries to use a list of URLs directly as start_urls, but Scrapy treats it as a single URL. This confusion arises because you do not yield individual requests for each URL, which is essential for Scrapy to function as expected.

The Solution: Customizing the RedditSpider

By utilizing the start_requests method, we can effectively manage how individual URLs are processed. Here's a step-by-step guide to modifying your spider:

1. Read URLs with start_requests

Instead of defining start_urls directly from the file, implement a custom start_requests function to handle reading and validating each URL individually.

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

2. The Parser Method

The parse method, which is already defined in your original spider, will remain mostly the same. It collects the desired data from each response received for the individual URLs.

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

3. File Format Verification

Ensure that your input file (reddit.txt) is correctly formatted, with one URL per line. Here’s how it should look:

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

Conclusion

By making these changes to your Scrapy spider, you’ll avoid the Unsupported URL scheme error and successfully crawl through multiple URLs specified in your reddit.txt file. This method enhances the efficiency of your scraping process and makes your data collection much more effective.

Happy Scraping! If you have further questions or need more help with Scrapy, feel free to ask!