UserController Validation and Exception Flow

[Dynavy]

UserController Validation Flow:

The **UserController ** handles the user CRUD endpoints requests. When a request is received, the flow follows these steps:

1. Receive Request:

   • The request typically includes user data such as name, email, and password. For user registration, a UserRegisterRequest DTO is used to encapsulate this information.

2. DTO Validation:

   • The UserRegisterRequest DTO is used for user registration requests. This DTO includes fields such as name, email, password, and phoneNumber. Validation annotations like @NotBlank, @Size, and custom validations ensure that:

     • The name field is not empty.

     • The email is properly formatted and not already in use.

     • The password has the required length (e.g., at least 8 characters).

     • The phoneNumber field is not empty.

   • These validations are handled by the ValidationService, ensuring that only valid user data proceeds to the next steps.

3. Validation Outcome:

   • If the user data passes all validations, the flow continues to the UserService to apply business logic.

   • If any validation fails (e.g., a missing field or an invalid email format), a ValidationErrorResponse DTO is returned, detailing the validation errors.

4. Business Logic and Custom Validations in UserService:

   • Once the DTO is valid, the UserService checks if the user already exists in the system by checking the email or phoneNumber. If a duplicate is found, a custom exception like IncorrectPasswordException or UserPermissionException is thrown.

   • The GlobalExceptionHandler catches the exception and returns an error response indicating that the user already exists.

5. Process User Data:

   • If no duplicate user is found, the user is created or updated in the system based on the provided data.

   • For new users, the system stores the user data, including the hashed password and any other relevant information.

6. Return Response:

   • After processing the user data, the system returns a success message or the newly created user data, depending on the request (e.g., a confirmation message for registration or updated user details).

7. GlobalExceptionHandler:

   • The GlobalExceptionHandler plays a key role in catching any exceptions, such as validation errors or custom exceptions (e.g., IncorrectPasswordException), and returning appropriate ValidationErrorResponse DTO with clear error messages.