Five complementary improvements to handler layer:
1. Fix Pre-Commit Hook
- Remove broken Perl-style regex (unsupported by Go)
- Use -short flag to exclude integration tests
- Tests now run successfully in pre-commit
2. Extract Duplicate Logic
- Remove 100+ lines of duplicate data preparation
- Both Home() and CVContent() now use prepareTemplateData()
- Reduce cv_pages.go from 290 to 120 lines (58% reduction)
3. Request/Response Types
- Create internal/handlers/types.go with structured types
- PDFExportRequest, LanguageRequest, PreferenceToggleRequest
- Type-safe parameter parsing with centralized validation
- Refactor ExportPDF to use typed requests
4. Middleware Extraction
- Create internal/middleware/preferences.go
- PreferencesMiddleware reads cookies once, stores in context
- Automatic migration of old preference values
- Ready for integration in routes
5. Handler Tests
- Add internal/handlers/cv_pages_test.go (190 lines, 15+ cases)
- Add internal/handlers/cv_htmx_test.go (325 lines, 20+ cases)
- Test language validation, toggles, cookies, methods
- Increase handler test coverage significantly
Testing:
- All unit tests pass (35+ new test cases)
- Pre-commit hook working
- Build succeeds
- No breaking changes
Benefits:
- Type safety: Compile-time parameter validation
- Code quality: 170 lines of duplication eliminated
- Testing: 100% increase in test files
- Architecture: Clean middleware pattern
- Developer experience: Self-documenting request types
Documentation:
- Create _go-learning/refactorings/004-handler-improvements.md
- Document all five improvements with examples
- Include metrics, testing strategy, and future improvements