clean-flutter-app

The clean-flutter-app is a reference implementation used in Rodrigo Manguinho's (Mango) Flutter training on Udemy. It serves as a practical example of building a Flutter application using a well-defined, decoupled architecture.

Key characteristics of this project include:

• Clean Architecture: Used to distribute responsibilities across distinct layers.
• TDD (Test-Driven Development): The primary methodology for development.
• SOLID Principles: Strict adherence to object-oriented design principles.
• Design Patterns: Implementation of various patterns to solve common software engineering problems.

The Remote Load Survey Result use case describes the workflow for fetching and validating survey results from a remote API.

Success Flow

1. The system makes a request to the survey result API URL.
2. The system validates the access token to ensure the user has permission to view the data.
3. The system validates the data received from the API.
4. The system delivers the survey result data.

Error Handling (Exceptions)

• Invalid URL: Returns an unexpected error message.
• Access Denied: Returns an access denied message.
• Invalid Response: Returns an unexpected error message.
• Server Failure: Returns an unexpected error message.

The Local Save Current Account use case is responsible for securely persisting the user's access token into the local cache.

Success Scenario

• The system successfully writes the user's access token to the cache in a secure manner.

Exception Scenario

• Failure to write to cache: If the cache operation fails, the system must return an unexpected error message.

The Local Load Current Account use case is responsible for retrieving the currently logged-in user's account information from local storage.

Success Scenario

1. The system requests the user's access token stored in the Secure Cache.
2. The system successfully returns the user's account data.

Exception Scenario: Cache Loading Failure

1. If the system fails to load data from the cache, it returns an unexpected error message.

The Remote Authentication use case defines the expected behavior for authenticating a user via an external API. It covers both the successful authentication flow and various error scenarios that the system must handle.

Success Flow

1. Validate input data.
2. Execute a request to the API login URL.
3. Validate the data received from the API.
4. Deliver the user account data.

Error Handling (Exceptions)

The system must return an unexpected error message for the following scenarios:

• Invalid URL
• Invalid input data
• Invalid API response
• Server failure

Specifically for invalid credentials, the system must return a specific error message informing the user that the credentials are incorrect.

The Local Validate Surveys use case ensures that the data currently held in the local cache is valid and usable.

Success Scenario:

• The system requests survey data from the cache and successfully validates the received data.

Error Scenarios:

• Error loading cache data: If an error occurs while attempting to load the cache, the system clears the cache data.
• Invalid data in cache: If the data retrieved from the cache is found to be invalid, the system clears the cache data.

The Local Save Surveys use case handles the persistence of new survey data into the local cache.

Success Scenario:

• The system successfully writes the new data into the cache.

Error Scenarios:

• Error saving to cache: If the write operation fails, the system returns an unexpected error message.

The Local Load Surveys use case is responsible for retrieving survey data stored in the local cache.

Success Scenario:

• The system requests survey data from the cache and successfully delivers the data.

Error Scenarios:

• Error loading cache data: The system returns an unexpected error message.
• Empty cache: The system returns an unexpected error message.

The Remote Save Survey Result use case describes the flow for retrieving survey result data from a remote API.

Success Flow

1. The system makes a request to the API URL for saving/retrieving survey results.
2. The system validates the access token to ensure the user has permission to view the data.
3. The system validates the data received from the API.
4. The system delivers the survey result data.

Error Handling

The system handles the following failure scenarios by returning error messages:

• Invalid URL: Returns an unexpected error message.
• Access Denied: Returns an access denied message.
• Invalid Response: Returns an unexpected error message.
• Server Failure: Returns an unexpected error message.