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Authentication Use Cases

Use cases encapsulate the business logic for authentication operations following Clean Architecture principles. Each use case represents a single operation that can be performed by the application.

​
LoginUseCase

Handles user login authentication. Location: lib/feature/auth/core/usecase/login_usecase.dart:13

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Constructor

​
repository
AuthRepository
required
The authentication repository implementation
LoginUseCase(AuthRepository repository);

​
Parameters

LoginParams
​
email
String
required
User’s email address
​
password
String
required
User’s password

​
Returns

​
Either<Failure, String>
Future
Returns a Right containing the authentication token on success, or a Left containing a Failure on error

​
Usage Example

final loginUseCase = LoginUseCase(authRepository);

final params = LoginParams('[email protected]', 'password123');
final result = await loginUseCase.call(params);

result.fold(
  (failure) => print('Login failed: ${failure.message}'),
  (token) => print('Login successful, token: $token'),
);

​
RegisterUseCase

Handles new user registration. Location: lib/feature/auth/core/usecase/register_usecase.dart:23

​
Constructor

​
repository
AuthRepository
required
The authentication repository implementation
RegisterUseCase(AuthRepository repository);

​
Parameters

RegisterParams
​
name
String
required
User’s display name (used for UI display or username generation)
​
username
String
required
User’s username
​
email
String
required
User’s email address
​
phone
String
required
User’s phone number
​
password
String
required
User’s password

​
Returns

​
Either<Failure, Map<String, dynamic>>
Future
Returns a Right containing registration response data on success, or a Left containing a Failure on error

​
Usage Example

final registerUseCase = RegisterUseCase(authRepository);

final params = RegisterParams(
  name: 'John Doe',
  username: 'johndoe',
  email: '[email protected]',
  phone: '+1234567890',
  password: 'securepass123',
);

final result = await registerUseCase.call(params);

result.fold(
  (failure) => print('Registration failed: ${failure.message}'),
  (data) => print('Registration successful: $data'),
);

​
LogoutUseCase

Handles user logout and token cleanup. Location: lib/feature/auth/core/usecase/logout_usecase.dart:6

​
Constructor

​
repository
AuthRepository
required
The authentication repository implementation
LogoutUseCase(AuthRepository repository);

​
Parameters

​
params
NoParams
required
No parameters required (use NoParams() instance)

​
Returns

​
Either<Failure, void>
Future
Returns a Right on successful logout, or a Left containing a Failure on error

​
Usage Example

final logoutUseCase = LogoutUseCase(authRepository);

final result = await logoutUseCase.call(NoParams());

result.fold(
  (failure) => print('Logout failed: ${failure.message}'),
  (_) => print('Logout successful'),
);

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CheckAuthStatusUseCase

Checks the current authentication status and retrieves the authenticated user. Location: lib/feature/auth/core/usecase/check_auth_status_usecase.dart:8

​
Constructor

​
repository
AuthRepository
required
The authentication repository implementation
CheckAuthStatusUseCase(AuthRepository repository);

​
Parameters

​
params
NoParams
required
No parameters required (use NoParams() instance)

​
Returns

​
Either<Failure, User?>
Future
Returns a Right containing the authenticated User (or null if not authenticated) on success, or a Left containing a Failure on error

​
Usage Example

final checkAuthUseCase = CheckAuthStatusUseCase(authRepository);

final result = await checkAuthUseCase.call(NoParams());

result.fold(
  (failure) => print('Auth check failed: ${failure.message}'),
  (user) {
    if (user != null) {
      print('User is authenticated: ${user.email}');
    } else {
      print('User is not authenticated');
    }
  },
);

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GetUserFromTokenUseCase

Retrieves user information from an authentication token. Location: lib/feature/auth/core/usecase/get_user_from_token_usecase.dart:8

​
Constructor

​
repository
AuthRepository
required
The authentication repository implementation
GetUserFromTokenUseCase(AuthRepository repository);

​
Parameters

​
token
String
required
Authentication token

​
Returns

​
Either<Failure, User>
Future
Returns a Right containing the User associated with the token on success, or a Left containing a Failure on error

​
Usage Example

final getUserUseCase = GetUserFromTokenUseCase(authRepository);

final token = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...';
final result = await getUserUseCase.call(token);

result.fold(
  (failure) => print('Failed to get user: ${failure.message}'),
  (user) => print('User retrieved: ${user.email}'),
);

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UseCase Base Class

All use cases implement the UseCase<Type, Params> interface. Location: lib/core/usecase/usecase.dart:5 
abstract class UseCase<Type, Params> {
  Future<Either<Failure, Type>> call(Params params);
}

class NoParams {}

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Type Parameters

​
Type
Generic
The return type of the use case operation
​
Params
Generic
The parameters type required by the use case

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Error Handling

All use cases return Either<Failure, T> which allows for functional error handling:
  • Right: Contains the successful result
  • Left: Contains a Failure object with error information
Common failure types:
  • ServerFailure: Server-side errors
  • AuthFailure: Authentication-specific errors
  • NetworkFailure: Network connectivity issues

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