fix: add User-Agent to MetadataFetcher HTTP client to prevent CDN 403s

[pthmas]

Summary

Adds .user_agent("atlas-server/0.1.0") to the reqwest client in MetadataFetcher::new. CDNs serving NFT metadata (IPFS gateways, OpenSea, etc.) classify requests with no User-Agent as bots and return 403, causing image_url to stay null and images to be blank.

Summary by CodeRabbit

Release Notes

• Refactor
  • Enhanced HTTP request header configuration for improved standards compliance
  • Optimized database connection parameter validation logic

[coderabbitai]

📝 Walkthrough

Walkthrough

Two minor changes to the backend HTTP client and database configuration: explicit User-Agent header added to outbound HTTP requests, and query parameter parsing logic simplified via pattern guard refactoring.

Changes

Cohort / File(s)	Summary
HTTP Client Configuration backend/crates/atlas-server/src/indexer/metadata.rs	Added explicit User-Agent header ("atlas-server/0.1.0") to reqwest::Client builder in MetadataFetcher::new.
Database Connection Parsing backend/crates/atlas-server/src/main.rs	Simplified dbname query parameter pattern matching from nested conditional to single guard-based pattern, preserving non-empty value semantics.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Possibly related issues

• fix: add User-Agent to MetadataFetcher HTTP client to prevent CDN 403s #65: Directly addresses the User-Agent header addition to the MetadataFetcher::new implementation.

Poem

🐰 A User-Agent hops along,
Identifying requests strong,
While patterns dance in guards so neat,
Two simple changes, clean and sweet!

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: adding a User-Agent header to prevent CDN 403 errors, which is the primary focus of the PR.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch issue-65

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@backend/crates/atlas-server/src/indexer/metadata.rs`:
- Around line 47-51: Add a unit test in a #[cfg(test)] mod tests block in the
same metadata.rs file that asserts the new User-Agent behavior: instantiate or
exercise the code path that creates the reqwest::Client (the client variable
built with .user_agent("atlas-server/0.1.0")) and verify that outgoing requests
include the "User-Agent: atlas-server/0.1.0" header (or that the client's
default headers contain that value); name the test clearly (e.g.,
test_user_agent_header) and keep it runnable with cargo test --workspace to
prevent regressions of the request-header logic.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: acad398a-9c9e-4fb4-baa1-195c17fbe7b5

📥 Commits

Reviewing files that changed from the base of the PR and between cf9cabb and 84947cb.

📒 Files selected for processing (2)

• backend/crates/atlas-server/src/indexer/metadata.rs
• backend/crates/atlas-server/src/main.rs