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 authorization by requiring HTTPS, rejecting origins with explicit ports, and tightening hostname matching (exact vs leading-dot subdomain rules).
  • Improved validation of AUTHORIZED_ORIGINS, including startup failures when it’s missing in production or malformed.

• Tests

  • Added/expanded coverage to verify authorization behavior across unset, single, wildcard, exact, and multi-entry origin configurations.

• Documentation

  • Updated .env.example guidance for AUTHORIZED_ORIGINS to clarify exact-host vs subdomain (leading-dot) matching.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 01d5405b-672a-4220-853a-2353fb42dbbf

📥 Commits

Reviewing files that changed from the base of the PR and between b9db698 and f5a09f7.

📒 Files selected for processing (1)

• package.json

📝 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	Refactored AUTHORIZED_ORIGINS parsing into parseAuthorizedOrigins() that normalizes by splitting, trimming, lowercasing, and filtering empty values, throwing in production if undefined or empty. Added isAuthorizedOrigin() to parse origins as URLs, enforce HTTPS-only with no explicit ports, and normalize casing. Added isAuthorizedHostname() supporting leading-dot subdomain suffix matching with length constraint, otherwise exact hostname equality. Replaced direct suffix matching with strict hostname validation in the on-request authorization check.
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 buildApp helper for isolated module reloading, request injection helpers for protected and public routes, and per-test cleanup. Covers startup validation (throws on malformed or missing AUTHORIZED_ORIGINS in production) and six configuration scenarios: unset origins (allow any), bare hostnames (exact + suffix-squatting and scheme validation), leading-dot entries (root and subdomains), exact subdomains (blocking parent/sub-subdomains), leading-dot patterns (subdomains only), and multiple entries (per-entry matching with cross-entry suffix-squatting prevention).

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' accurately reflects the main change: implementing enhanced authorized origins handling for the API with validation, production safeguards, and support for both exact-host and subdomain-matching patterns.
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 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