Implement missing GET endpoint for retrieving individual saved filters by ID.
This completes the CRUD API for saved filters and enables mobile/SPA clients
to fetch filter details on-demand.
Backend Implementation:
- Add GetSavedFilterByID() handler method (internal/handlers/filters.go)
- Parse filter ID from URL parameter
- Validate UUID format, return 400 for invalid IDs
- Call service layer for business logic + ownership verification
- Return 404 if filter not found or doesn't belong to user
- Return 200 with filter object including filters JSONB
- Add GetSavedFilterByID() service method (internal/services/filters.go)
- Call existing database query GetSavedFilterByID
- Verify filter exists and belongs to user
- Return descriptive error: "filter not found or access denied"
- Reuses existing database query (no new SQL needed)
- Register GET /:id route (internal/router/filters.go)
- Add route before existing GET "" route
- Follows RESTful routing conventions
Integration Tests (cmd/server/tests/filters_test.go):
- Test success case: Create filter, retrieve by ID, verify data
- Test error case: Invalid UUID format returns 400
- Test error case: Non-existent filter returns 404
- Test error case: No authentication returns 401
- Test security case: Cross-user access returns 404 (not 403)
- Admin creates filter, regular user tries to access
- Uses setup.Token (admin) and setup.RegularToken
- Verifies information leakage prevention
API Design:
- Endpoint: GET /api/saved-filters/:id
- Authentication: JWT token required
- Response format: SavedFilterResponse with filters as JSON
- Error responses: 400 (invalid ID), 401 (no auth), 404 (not found)
- Security: Returns 404 for cross-user access (hides existence)
Benefits:
- Completes CRUD API for saved filters
- Enables future mobile/SPA clients
- Follows existing handler/service/test patterns
- Comprehensive security testing
- No database changes required (reuses existing queries)
Follows PROJECT_GUIDELINES.md service layer architecture and testing patterns.
Add complete backend implementation for saved filters CRUD operations
with proper service layer architecture and RESTful API endpoints.
Service Layer (internal/services/filters.go):
- NewFiltersService() constructor following project patterns
- GetSavedFilters(): Retrieve all filters for user + resource type
- CreateSavedFilter(): Create filter with duplicate name validation
- UpdateSavedFilter(): Update filter with ownership verification
- DeleteSavedFilter(): Delete filter with user scoping
Business Logic:
- Filter name uniqueness enforced per user + resource type
- User ownership validation on all operations (JWT user_id)
- JSONB marshaling/unmarshaling for flexible filter storage
- Proper error wrapping with context messages
Handler Layer (internal/handlers/filters.go):
- NewFiltersHandler() constructor (receives db.Queries)
- GetSavedFilters: GET /api/saved-filters?resource_type=X
- CreateSavedFilter: POST /api/saved-filters
- UpdateSavedFilter: PUT /api/saved-filters/:id
- DeleteSavedFilter: DELETE /api/saved-filters/:id
Content Negotiation:
- Supports both JSON (API clients) and HTML (HTMX) responses
- wantsHTML() helper checks Accept header
- HX-Redirect header for HTMX form submissions
- Proper status codes (200, 201, 204, 400, 401, 404, 409)
Router Configuration:
- registerFiltersRoutes() function in internal/router/filters.go
- JWT middleware protection on all endpoints
- RESTful route structure: /api/saved-filters
- Registered in main router.go RegisterRoutes() function
- Added FiltersHandler to router.Config struct
Test Infrastructure:
- Added FiltersHandler to test server setup (test_helpers_test.go)
- FiltersHandler initialized in setupTestServer() function
- Router.Config includes FiltersHandler for integration tests
Code Quality:
- Follows PROJECT_GUIDELINES.md service layer patterns
- Uses database models (not custom domain models)
- JSONB returned as []byte (matches collections pattern)
- All errors wrapped with context using fmt.Errorf
- Handlers create services internally (not dependency injection)
Part of: Saved Filters Implementation (Phase 2: Backend)
Related: #saved-filters-feature
john-okeefe