fix: Improve NAR file serving and remove old URL prefix workaround

[kalbasit]

Update testdata server to properly handle NAR file paths with compression
extensions and support lookups by both original and normalized NAR hashes.
Also remove the old string replacement workaround from upstream cache since
URLs are now normalized through the Normalize() method.

Changes:

• testdata/server.go:

  • Fix path construction to only append compression extension if non-empty
  • Add support for fetching narinfo by NAR hash (used when only NAR hash available)
  • Add support for fetching NARs by normalized hash (with prefix stripped)
  • Build normalized NAR paths with proper compression extension handling

• pkg/cache/upstream/cache.go:

  • Remove ReplaceAll workaround for URL prefix trimming
  • URL normalization now handled via nar.URL.Normalize()

This fixes issues with NAR files that have no compression (extension would have
been ".nar." instead of ".nar") and ensures test server can serve NARs regardless
of whether they're requested using the original prefixed hash or the normalized hash.

Part of #806

Co-Authored-By: Claude Haiku 4.5 noreply@anthropic.com

[dosubot]

Related Documentation

Checked 7 published document(s) in 1 knowledge base(s). No updates required.

^{How did I do? Any feedback?}  

[kalbasit]

• fix: harden NAR hash validation and improve URL parsing #842
• fix: harden the narinfo route pattern #841
• fix: harden the narinfo hash validation #840
• fix: Fix test data generation and skip signature verification #839
• fix: Improve NAR file serving and remove old URL prefix workaround #838 👈 (View in Graphite)
• fix: Apply NAR URL normalization in storage layer #837
• feat: Add NAR URL normalization function and support dashes/underscores in hashes #836
• main

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[gemini-code-assist]

Summary of Changes

Hello @kalbasit, 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 refines how NAR (Nix Archive) files are served and processed, primarily by enhancing the test server's ability to handle various NAR URL formats, including those with and without compression extensions, and supporting lookups by different hash representations. Concurrently, it streamlines the upstream cache logic by removing a manual URL prefix trimming workaround, relying instead on a centralized normalization utility. These changes collectively improve the robustness and consistency of NAR file handling.

Highlights

• NAR File Serving Improvements: The testdata server now correctly handles NAR file paths, ensuring compression extensions are appended only when present, and supports fetching NARs by both their original and normalized hashes.
• URL Prefix Workaround Removal: An outdated string replacement workaround for trimming URL prefixes in the upstream cache has been removed, as URL normalization is now handled consistently via the nar.URL.Normalize() method.
• Test Data Alignment: The nar7.go test data has been updated to reflect the non-prefixed format for NAR URLs, aligning with the new normalization logic.

Changelog

• pkg/cache/upstream/cache.go
  • Removed strings.ReplaceAll call that was used to trim a hash prefix from NarURL, as normalization is now handled by nar.URL.Normalize().
• testdata/nar7.go
  • Updated the NarInfoText URL to remove the narinfo hash prefix, aligning it with the non-prefixed format.
• testdata/server.go
  • Imported the github.com/kalbasit/ncps/pkg/nar package to utilize its URL normalization capabilities.
  • Added logic to support fetching narinfo by the NAR hash directly.
  • Refactored NAR path construction to correctly append compression extensions (e.g., .nar.zst) only when an extension is present, preventing .nar. for uncompressed files.
  • Implemented support for serving NARs using their normalized hash (with the prefix stripped), including handling compression extensions for these normalized paths.

Activity

• No human activity has occurred on this pull request yet.

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[gemini-code-assist]

Code Review

The pull request effectively improves NAR file serving in the testdata server and removes an outdated URL prefix workaround in the upstream cache. The changes ensure that the test server correctly handles NAR file paths with compression extensions and supports lookups by both original and normalized NAR hashes. The removal of the strings.ReplaceAll workaround in pkg/cache/upstream/cache.go is a good step towards cleaner code, as URL normalization is now handled by the nar.URL.Normalize() method.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.41%. Comparing base (c6e9967) to head (44963b2).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #838   +/-   ##
=======================================
  Coverage   85.41%   85.41%           
=======================================
  Files           2        2           
  Lines         480      480           
=======================================
  Hits          410      410           
  Misses         65       65           
  Partials        5        5           

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