Better Auth Client

A pure dart client package for Better Auth

Plugins Supported

• x Two Factor Authentication
• x Anonymous Authentication
• x Username
• x Magic Link
• x Phone Number
• x Email OTP

Installation

dart pub add better_auth_client

Setup

Client Side

This package is pure dart and does not require any native code. However, it uses dio for networking so make sure internet permission is enabled in android and macos.

Server Side

• This package requires bearer and expo plugin to be enabled in your better auth server.
• Please setup universal links(for ios) and app links(for android) to make use of oauth sign in.

Oauth Specific Setup

• Setup universal links(for ios) and app links(for android) using app_links or any other package you prefer.
• Add your url scheme in trustedOrigins array of better auth.

trustedOrigins: ["bac://fyi.procrastinator.better-auth-client", "bac://"],

Usage

Since this package is pure dart, it does not bother with any token storage method. You have to implement your own token storage by extending TokenStore class.

class InMemoryTokenStore extends TokenStore {
  String? _token;

  @override
  Future<String> getToken() {
    return Future.value(_token ?? "");
  }

  @override
  Future<void> saveToken(String? token) {
    _token = token;
    return Future.value();
  }
}

Now you can create a client and use it across the app.

final client = BetterAuthClient(baseUrl: "http://localhost:3000/api/auth", tokenStore: InMemoryTokenStore(), scheme: "bac://");

Sign In

final response = await client.signIn.email("test@mail.com","Password","Test User");

The API of this package is similar to that of Better Auth's JS Client.

Oauth

This package does not handle oauth redirects. You have to handle it yourself using flutter_web_auth_2 or any other package you prefer.

Custom User Models

Better Auth Client allows you to customize the User model to include additional properties returned by your server. There are three approaches you can use:

Approach 1: Dynamic Map

This approach automatically collects all non-standard properties into a customProperties map.

// Sign in to get a user with custom properties
final response = await client.signIn.email("test@example.com", "password");
final user = response.data;

// Access custom properties
final customValue = user?.customProperties["customField"];

final typedValue = user?.getCustomProperty<String>("customField");

Approach 2: Extending the Base User Class

Use the ExtendableUser class for a cleaner inheritance approach:

class CustomUser extends ExtendableUser {
  final String customField;

  CustomUser({
    required super.id,
    required super.email,
    required super.name,
    super.image,
    required super.createdAt,
    required super.updatedAt,
    super.emailVerified,
    required this.customField,
    super.twoFactorEnabled,
    super.username,
    super.displayUsername,
    super.isAnonymous,
    super.phoneNumber,
    super.phoneNumberVerified,
    super.role,
    super.banned,
    super.banReason,
    super.banExpires,

  });

  factory CustomUser.fromJson(Map<String, dynamic> json) {
    return CustomUser(
      id: json['id'],
      email: json['email'],
      name: json['name'],
      image: json['image'],
      createdAt: DateTime.parse(json['createdAt']),
      updatedAt: DateTime.parse(json['updatedAt']),
      emailVerified: json['emailVerified'],
      twoFactorEnabled: json['twoFactorEnabled'],
      username: json['username'],
      displayUsername: json['displayUsername'],
      isAnonymous: json['isAnonymous'],
      phoneNumber: json['phoneNumber'],
      phoneNumberVerified: json['phoneNumberVerified'],
      role: json['role'],
      banned: json['banned'],
      banReason: json['banReason'],
      banExpires: json['banExpires'],
      customField: json['customField'],
    );
  }

  @override
  Map<String, dynamic> toJson() {
    final json = super.toJson();
    json['customField'] = customField;
    return json;
  }
}

// Initialize client with custom user factory
final client = BetterAuthClient(
  baseUrl: "https://api.example.com",
  tokenStore: myTokenStore,
  fromJsonUser: CustomUser.fromJson,
);