feat(api): authorized origins

[alfetopito]

Summary

Harden authorized origins.

Addresses feedback from https://github.com/cowprotocol/infrastructure/pull/5701

Note: in order to preserve current behaviour of accepting subdomains, BFF configs need to be updated from:

"cow.fi, cowswap.vercel.app, cowswap-dev.vercel.app, explorer-dev.vercel.app, swap-dev-5u6.pages.dev, explorer-dev-dxz.pages.dev"

to

".cow.fi, .cowswap.vercel.app, .cowswap-dev.vercel.app, .explorer-dev.vercel.app, .swap-dev-5u6.pages.dev, .explorer-dev-dxz.pages.dev"

Testing

Unit tests

Summary by CodeRabbit

Release Notes

• Bug Fixes

  • Strengthened origin validation to enforce HTTPS and eliminate port-based authorization bypasses.
  • Enhanced subdomain pattern matching for origin configuration using leading-dot notation.
  • Improved configuration parsing and normalization for authorization entries.

• Tests

  • Added comprehensive test coverage for origin authorization across multiple configurations.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 1ba4b942-220e-4c76-8e01-01f9404bd123

📥 Commits

Reviewing files that changed from the base of the PR and between c0678c7 and bee7a1e.

📒 Files selected for processing (2)

• apps/api/src/app/plugins/bffAuth.spec.ts
• apps/api/src/app/plugins/bffAuth.ts

📝 Walkthrough

Walkthrough

This PR enforces stricter origin authorization for the BFF with HTTPS-only validation and leading-dot wildcard subdomain matching, documented in environment examples and tested across six configuration scenarios. A separate fix improves test isolation by properly cleaning environment variables in the Coingecko test suite.

Changes

Strict Origin Authorization with Subdomain Matching

Layer / File(s)	Summary
Origin authorization implementation apps/api/src/app/plugins/bffAuth.ts	Added internal helpers isAuthorizedOrigin(), isAuthorizedHostname(), and parseOrigin() to enforce HTTPS-only origin validation with support for leading-dot subdomain wildcard patterns. Updated AUTHORIZED_ORIGINS parsing to trim, lowercase, and filter empty values. Replaced suffix-based matching with strict hostname matching.
Configuration examples .env.example	Updated AUTHORIZED_ORIGINS documentation with clarifying comments on exact-host vs subdomain matching. Expanded example from cow.fi to cow.fi,.cow.fi to demonstrate both bare and leading-dot subdomain entry forms.
Authorization test coverage apps/api/src/app/plugins/bffAuth.spec.ts	Added comprehensive Jest test suite with six scenarios: unset origins (allow any), bare hostnames with suffix-squatting and scheme validation, leading-dot entries for subdomain patterns, exact subdomains blocking parent/sub-subdomains, leading-dot patterns blocking bare domains, and multiple entries preventing cross-entry suffix-squatting. Includes buildApp helper for isolated module reloading and request injection helpers with optional origin headers.

Test Environment Isolation

Layer / File(s)	Summary
Environment variable cleanup in test libs/repositories/src/datasources/coingecko.test.ts	Fixed the getCoingeckoProClient error-path test to preserve and restore the original process.env.COINGECKO_API_KEY using a try/finally block, preventing environment leakage across test runs.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Poem

A rabbit hops through origins secure,
HTTPS paths and subdomains pure,
Leading-dot patterns match just right,
Tests confirm each auth-check bright! 🐰✨

🚥 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 'feat(api): authorized origins' directly and specifically summarizes the main change: hardening authorized origins handling in the API.
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.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/authorized-origins

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@apps/api/src/app/plugins/bffAuth.ts`:
- Around line 12-15: The parsing currently trims and filters AUTHORIZED_ORIGINS
into an array (the domains variable result) but doesn't fail when the env is
present yet yields no valid entries, which silently disables origin protection;
change the startup logic that produces the parsed origins array
(authorizedOrigins) to detect when process.env.AUTHORIZED_ORIGINS is set but
parsed array length === 0 and then fail-closed (throw an Error or exit) with a
clear message about malformed AUTHORIZED_ORIGINS instead of returning an empty
array, and also update the middleware conditional that currently skips auth when
authorizedOrigins is empty to assume a malformed configuration rather than
allowing requests (i.e., require successful parse or stop startup).

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

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

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: e6df991b-a933-4cf6-970d-32d229ba3230

📥 Commits

Reviewing files that changed from the base of the PR and between a160920 and c0678c7.

📒 Files selected for processing (4)

• .env.example
• apps/api/src/app/plugins/bffAuth.spec.ts
• apps/api/src/app/plugins/bffAuth.ts
• libs/repositories/src/datasources/coingecko.test.ts