Lifecycle & Validation

Every HTTP request in RapidREST runs through a fixed pipeline before your handler code executes, and again afterward before the response is sent:

auth strategies → @RequireRole → ACL permission check → @Validate → @Before → handler → @After

Authentication, role checks, and ACL permissions are covered in Auth & RBAC.

@Validate(func)

Runs a validation function before the handler. Throw to reject the request and a proper 400 error message will be returned to the client.

@Post()
@Validate('validateCreate')
async createPet(pet: Pet) {
  return this.petService.create(pet);
}

private validateCreate(pet: Pet) {
  if (!pet.name) throw new Error('name is required');
}

func can be a function reference or the string name of a method on the same class.

@Before(func) / @After(func)

Run one or more functions immediately before or after the handler. Both accept a single function/name or an array of them:

@Get('/:id')
@After('cleanPII')
async findById(@Param('id') id: string, @User user?: any) {
  return super.findById(id);
}

private cleanPII(pet: Pet, @User user?: any) {
  if (!user) pet.ownerContact = undefined;
  return pet;
}

This is the standard pattern for post-processing a response, for example stripping fields a caller isn't authorized to see, or adding computed fields, without duplicating the whole handler.

@ContentType(type)

Overrides the response content-type header (JSON is the default):

@Get()
@ContentType('text/html')
getHtml(): string {
  return '<h1>Hello</h1>';
}