[Fixes #13862] Improvements of Empty datasets

[sijandh35]

Fixes #13862

Checklist

Reviewing is a process done by project maintainers, mostly on a volunteer basis. We try to keep the overhead as small as possible and appreciate if you help us to do so by completing the following items. Feel free to ask in a comment if you have troubles with any of them.

For all pull requests:

• Confirm you have read the contribution guidelines
• You have sent a Contribution Licence Agreement (CLA) as necessary (not required for small changes, e.g., fixing typos in the documentation)
• Make sure the first PR targets the master branch, eventual backports will be managed later. This can be ignored if the PR is fixing an issue that only happens in a specific branch, but not in newer ones.

The following are required only for core and extension modules (they are welcomed, but not required, for contrib modules):

• There is a ticket in https://github.com/GeoNode/geonode/issues describing the issue/improvement/feature (a notable exemption is, changes not visible to end-users)
• The issue connected to the PR must have Labels and Milestone assigned
• PR for bug fixes and small new features are presented as a single commit
• PR title must be in the form "[Fixes #<issue_number>] Title of the PR"
• New unit tests have been added covering the changes, unless there is an explanation on why the tests are not necessary/implemented

Submitting the PR does not require you to check all items, but by the time it gets merged, they should be either satisfied or inapplicable.

[gemini-code-assist]

Summary of Changes

Hello @sijandh35, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly improves the system's resilience and user experience when dealing with datasets that contain no features. It introduces a robust fallback strategy for downloading empty datasets, ensuring that users can still retrieve data even if the primary download method fails. Additionally, it refines the rollback process for empty dataset uploads, preventing accidental resource deletion and enhancing overall data management reliability.

Highlights

• Improved Download Handling for Empty Datasets: Implemented a fallback mechanism for WPS downloads of empty vector datasets. If a WPS request fails with an 'empty feature collection' error, the system now attempts to download the data using a WFS GetFeature request, mapping common formats like ZIP and CSV to their WFS equivalents.
• Enhanced Rollback Behavior for Empty Datasets: Modified the EmptyDatasetHandler to prevent the deletion of resources during rollback operations for empty datasets. This ensures data integrity and avoids unintended data loss in scenarios where an empty dataset upload might encounter an issue.

🧠 New Feature in Public Preview: You can now enable Memory to help Gemini Code Assist learn from your team's feedback. This makes future code reviews more consistent and personalized to your project's style. Click here to enable Memory in your admin console.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request improves the handling of empty datasets. In download_handler.py, it adds a fallback to WFS GetFeature when a WPS download fails for an empty collection, which is a good improvement. However, there's a bug in the new error handling logic where an XML parsing failure doesn't stop execution, and the XPath for finding exceptions could be more correct. In empty_dataset/handler.py, the change to override the rollback method to prevent deletion of empty datasets is well-implemented and clearly documented. My review includes suggestions to fix the identified issues.

[gemini-code-assist]

The XPath expression *//ows:Exception is not standard for xml.etree.ElementTree and might not work as intended. To find the ows:Exception element at any depth within the XML document, you should use .//ows:Exception. The or root.find("ows:Exception", ...) part becomes redundant with this change, simplifying the code.

                exc = root.find('.//ows:Exception', namespaces=namespaces)

[codecov]

Codecov Report

❌ Patch coverage is 40.74074% with 16 lines in your changes missing coverage. Please review.
✅ Project coverage is 74.17%. Comparing base (3ed2514) to head (e78bcce).
⚠️ Report is 9 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #13864       +/-   ##
===========================================
+ Coverage   52.15%   74.17%   +22.01%     
===========================================
  Files         944      944               
  Lines       56335    56419       +84     
  Branches     7626     7634        +8     
===========================================
+ Hits        29380    41846    +12466     
+ Misses      25588    12893    -12695     
- Partials     1367     1680      +313     

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.