Request Lifecycle

Understand how an HTTP request flows through the Ever Gauzy API from entry to response.

Overview

Phase 1: Middleware

Express middleware processes the raw request:

Middleware	Purpose
helmet	Security headers
cors	CORS handling
compression	Response compression
body-parser	JSON body parsing
cookie-parser	Cookie parsing

Phase 2: Guards

Guards determine if the request is authorized:

Guard	Order	Purpose
TenantPermissionGuard	1st	Extract and validate tenant
PermissionGuard	2nd	Check user permissions
RoleGuard	3rd	Check user role (optional)
FeatureFlagGuard	4th	Check feature availability

Phase 3: Interceptors

Interceptors transform request/response:

Interceptor	Purpose
TransformInterceptor	Standardize response format
TimeoutInterceptor	Request timeout handling
LazyLoadInterceptor	Lazy-load relations

Phase 4: Pipes

Pipes validate and transform input:

Pipe	Purpose
ValidationPipe	DTO class-validator
UUIDValidationPipe	UUID parameter validation
ParseJsonPipe	JSON query param parsing

Phase 5: Controller → Service → Repository

The actual business logic execution:

1. Controller — route handler, delegates to service
2. Service — business logic, tenant filtering
3. Repository — database operations (TypeORM/MikroORM)

Phase 6: Response

The response flows back through interceptors for transformation before being sent to the client.

Error Handling

Errors at any phase are caught by the global exception filter:

Related Pages

• Guard & Interceptor Chain — detailed guard docs
• Error Handling Architecture — error patterns
• Backend Architecture — system overview