UserService class

Service for managing user-specific data and preferences.

This service handles user identification and persistent storage of user-specific settings using SharedPreferences. It ensures each device has a unique, persistent user identifier for tracking observations and user preferences across app sessions.

User Identification Strategy

The service uses a device-based identification approach:

• Anonymous: No personal information is collected or stored
• Persistent: User ID persists across app restarts and updates
• Unique: Each device gets a unique UUID v4 identifier
• Privacy-Focused: No tracking across devices or accounts

Data Storage

User data is stored locally using SharedPreferences:

• Location: Platform-specific secure storage
• Persistence: Survives app updates and device restarts
• Security: Uses platform's secure storage mechanisms
• Backup: May be included in device backups (platform-dependent)

Usage Example

final prefs = await SharedPreferences.getInstance();
final uuid = Uuid();
final userService = UserService(prefs: prefs, uuid: uuid);

// Get user ID (creates one if it doesn't exist)
final userId = await userService.getUserId();
print('User ID: $userId');

// Use in observations
final observation = Observation(
  id: 'obs_123',
  userId: userId,
  // ... other fields
);

Privacy Considerations

• User IDs are generated locally and never transmitted to identify individuals
• IDs are used only for data organization and quality assessment
• No personal information is associated with user IDs
• Users can reset their ID by clearing app data

Integration Points

The service integrates with:

• Observation model for tracking observation sources
• Analytics systems for usage patterns (anonymized)
• Data quality systems for contribution assessment

See also:

• Observation for observation data that includes user IDs
• SharedPreferences for the underlying storage mechanism
• Uuid for unique identifier generation