5. REST API Implementation

[mrserverless]

• 5.1 Create rest/errors.go
  • Define error response structure (code, message, details)
  • Error constants (NOT_FOUND, INVALID_INPUT, INTERNAL_ERROR)
  • Error response helpers (JSON formatting)
• 5.2 Implement rest/middleware.go
  • Request logging middleware (request ID, method, path, duration)
  • Error recovery middleware (panic handling)
  • CORS middleware (configurable origins)
  • Content-Type validation middleware (require application/json for POST/PUT)
• 5.3 Implement rest/handlers.go - Account handlers
  • GET /accounts/{id} → AccountService.RetrieveCurrentAccount
  • GET /accounts/{id}/balance → AccountService.RetrieveCurrentAccountBalance
  • Input validation (ID not empty)
  • Error handling (not found, internal errors)
  • JSON response formatting
• 5.4 Implement rest/handlers.go - Transaction handlers
  • GET /transactions/{id} → TransactionService.RetrievePaymentTransaction
  • GET /accounts/{id}/transactions → TransactionService.RetrievePaymentTransactionHistory
  • Query parameter parsing (fromDate, toDate, limit, offset)
  • Input validation (date range, pagination parameters)
  • Error handling and JSON response
• 5.5 Implement rest/handlers.go - Consent handlers
  • GET /consents/{id} → ConsentService.RetrieveConsent
  • GET /consents/{id}/status → ConsentService.RetrieveConsentStatus
  • Input validation and error handling
  • JSON response formatting
• 5.6 Implement rest/server.go
  • NewRESTServer(services...) function
  • Configure http.ServeMux with all routes
  • Apply middleware stack
  • Health check endpoint (GET /health)
  • Export handler for embedding in unified server
• 5.7 Write unit tests for REST handlers
  • Test each endpoint with mock domain services
  • Test error cases (not found, invalid input)
  • Test query parameter parsing
  • Test error response formatting

Source: openspec/changes/bootstrap-mvp-foundation/tasks.md