AuthService - Trello App

Overview

The AuthService class provides comprehensive authentication functionality for the Flutter application, including email/password authentication, Google Sign-In, user profile management, and user search capabilities. Location: lib/services/auth_service.dart

Dependencies

firebase_auth - Firebase Authentication
cloud_firestore - Firestore database
firebase_storage - Firebase Storage for profile images
google_sign_in - Google Sign-In integration
logger - Logging functionality

Authentication Methods

registerWithEmailAndPassword

Registers a new user with email and password credentials.

Future<User?> registerWithEmailAndPassword(String email, String password)

String

required

The user’s email address

password

String

required

The user’s password

User?

Future<User?>

Returns a User object if registration is successful, or null if an error occurs

Example

final authService = AuthService();
final user = await authService.registerWithEmailAndPassword(
  '[email protected]',
  'securePassword123'
);

if (user != null) {
  print('Registration successful: ${user.uid}');
} else {
  print('Registration failed');
}

Error Handling

Returns null if registration fails
Errors are logged using the Logger instance
Common errors include: invalid email format, weak password, email already in use

signInWithEmailAndPassword

Authenticates an existing user with email and password.

Future<User?> signInWithEmailAndPassword(String email, String password)

String

required

The user’s email address

password

String

required

The user’s password

User?

Future<User?>

Returns a User object if sign-in is successful, or null if an error occurs

Example

final authService = AuthService();
final user = await authService.signInWithEmailAndPassword(
  '[email protected]',
  'securePassword123'
);

if (user != null) {
  print('Sign-in successful: ${user.uid}');
} else {
  print('Invalid credentials');
}

Error Handling

Returns null if authentication fails
Errors are logged automatically
Common errors include: user not found, wrong password, too many requests

signInWithGoogle

Authenticates a user using Google Sign-In.

Future<User?> signInWithGoogle()

User?

Future<User?>

Returns a User object if sign-in is successful, or null if the user cancels or an error occurs

Behavior

Opens Google Sign-In dialog
Automatically creates user profile in Firestore if it doesn’t exist
Uses displayName from Google account as the user’s name
Returns null if user cancels the sign-in dialog

Example

final authService = AuthService();
final user = await authService.signInWithGoogle();

if (user != null) {
  print('Google sign-in successful: ${user.displayName}');
} else {
  print('Sign-in cancelled or failed');
}

Firestore Integration

Show Automatic Profile Creation

When a user signs in with Google for the first time:

Checks if user profile exists in Firestore
If not found, calls saveUserProfile() automatically
Uses Google account’s display name or ‘Sin nombre’ as default
Profile image is not uploaded (set to null)

signOut

Signs out the current user from both Firebase Auth and Google Sign-In.

Future<void> signOut()

Example

final authService = AuthService();
await authService.signOut();
print('User signed out successfully');

Profile Management

saveUserProfile

Saves or updates user profile information in Firestore, including optional profile image upload to Firebase Storage.

Future<void> saveUserProfile(
  String uid,
  String name,
  String surname,
  File? profileImage
)

uid

String

required

The user’s unique identifier from Firebase Auth

name

String

required

The user’s first name

surname

String

required

The user’s surname/last name

profileImage

File?

Optional profile image file. If provided, it will be uploaded to Firebase Storage at profileImages/{uid}.jpg

Firestore Document Structure

{
  "name": "John",
  "surname": "Doe",
  "photoUrl": "https://firebasestorage.googleapis.com/..."
}

Example

import 'dart:io';

final authService = AuthService();
final user = authService.currentUser;

if (user != null) {
  final imageFile = File('/path/to/profile.jpg');
  await authService.saveUserProfile(
    user.uid,
    'John',
    'Doe',
    imageFile
  );
}

Storage Behavior

Show Image Upload Process

If profileImage is not null:
- Uploads image to Firebase Storage at path profileImages/{uid}.jpg
- Retrieves download URL
- Stores URL in Firestore
If profileImage is null:
- photoUrl field is set to null in Firestore

getUserProfile

Retrieves user profile data from Firestore.

Future<Map<String, dynamic>?> getUserProfile(String uid)

uid

String

required

The user’s unique identifier

Map<String, dynamic>?

Future<Map<String, dynamic>?>

Returns a map containing user profile data, or null if the profile doesn’t exist or an error occurs

Example

final authService = AuthService();
final profile = await authService.getUserProfile('user_uid_123');

if (profile != null) {
  print('Name: ${profile['name']}');
  print('Surname: ${profile['surname']}');
  print('Photo URL: ${profile['photoUrl']}');
}

User Search

searchUsersByName

Searches for users by name using Firestore queries.

Future<List<UserProfile>> searchUsersByName(String name)

name

String

required

The name or partial name to search for

List<UserProfile>

Future<List<UserProfile>>

Returns a list of UserProfile objects matching the search query. Returns empty list if no matches found or error occurs.

Search Behavior

Uses Firestore range queries with \uf8ff character for prefix matching
Searches the name field in the users collection
Case-sensitive search

Example

final authService = AuthService();
final users = await authService.searchUsersByName('John');

for (var user in users) {
  print('Found user: ${user.name}');
}

searchUsersByNameOrEmail

Searches for users by either name or email address.

Future<List<UserProfile>> searchUsersByNameOrEmail(String query)

query

String

required

The search query to match against name or email fields

List<UserProfile>

Future<List<UserProfile>>

Returns a combined list of UserProfile objects matching either name or email. Returns empty list if no matches found or error occurs.

Search Strategy

Show Dual Query Approach

Executes first query against name field
Executes second query against email field
Combines both result sets
May contain duplicates if a user matches both criteria

Example

final authService = AuthService();
final users = await authService.searchUsersByNameOrEmail('john');

print('Found ${users.length} users matching "john"');
for (var user in users) {
  print('${user.name} - ${user.email}');
}

Properties

currentUser

Gets the currently authenticated user.

User? get currentUser

User?

Returns the current User object if authenticated, or null if no user is signed in

Example

final authService = AuthService();
final user = authService.currentUser;

if (user != null) {
  print('Current user: ${user.email}');
} else {
  print('No user signed in');
}

displayName

Gets the display name of the current user.

String? get displayName

String?

Returns the display name, or null if not set or no user is signed in

photoURL

Gets the photo URL of the current user.

String? get photoURL

String?

Returns the photo URL, or null if not set or no user is signed in

Error Handling Best Practices

All methods in AuthService handle errors gracefully:

Methods return null or empty lists on failure
Errors are automatically logged using Logger
No exceptions are thrown to the caller
Always check return values before proceeding

Example Error Handling

final authService = AuthService();

// Check for null returns
final user = await authService.signInWithEmailAndPassword(
  email,
  password
);

if (user == null) {
  // Handle authentication failure
  showErrorDialog('Invalid credentials');
  return;
}

// Proceed with authenticated user
navigateToHome();

Services

Models

Screens

​Overview

​Dependencies

​Authentication Methods

​registerWithEmailAndPassword

​Example

​Error Handling

​signInWithEmailAndPassword

​Example

​Error Handling

​signInWithGoogle

​Behavior

​Example

​Firestore Integration

​signOut

​Example

​Profile Management

​saveUserProfile

​Firestore Document Structure

​Example

​Storage Behavior

​getUserProfile

​Example

​User Search

​searchUsersByName

​Search Behavior

​Example

​searchUsersByNameOrEmail

​Search Strategy

​Example

​Properties

​currentUser

​Example

​displayName

​photoURL

​Error Handling Best Practices

​Example Error Handling

Build docs developers (and LLMs) love

Overview

Dependencies

Authentication Methods

registerWithEmailAndPassword

Example

Error Handling

signInWithEmailAndPassword

Example

Error Handling

signInWithGoogle

Behavior

Example

Firestore Integration

signOut

Example

Profile Management

saveUserProfile

Firestore Document Structure

Example

Storage Behavior

getUserProfile

Example

User Search

searchUsersByName

Search Behavior

Example

searchUsersByNameOrEmail

Search Strategy

Example

Properties

currentUser

Example

displayName

photoURL

Error Handling Best Practices

Example Error Handling