Examples

Welcome to the Fasq Examples section! Here you’ll find comprehensive, real-world examples that demonstrate how to use Fasq in various scenarios. Each example includes complete, working code that you can copy and adapt for your own projects.

What You’ll Learn

Our examples cover the most common patterns and use cases you’ll encounter when building Flutter applications with Fasq:

• API Integration - REST APIs, GraphQL, and authentication
• Data Management - CRUD operations, real-time updates, and caching
• File Operations - Upload, download, and image processing
• Database Integration - SQLite, PostgreSQL, and MongoDB
• Advanced Patterns - Optimistic updates, error handling, and performance

Example Categories

API Integration

REST API

Complete examples of integrating with REST APIs using Fasq. Learn how to:

• Set up HTTP clients and API services
• Handle authentication and authorization
• Implement CRUD operations
• Manage loading states and error handling
• Cache API responses effectively

GraphQL

Comprehensive GraphQL integration examples. Learn how to:

• Configure GraphQL clients
• Write queries, mutations, and subscriptions
• Handle GraphQL-specific errors
• Use fragments and batch operations
• Implement real-time updates

Authentication

Complete authentication implementation patterns. Learn how to:

• Implement login and logout flows
• Manage tokens and refresh tokens
• Create protected routes
• Handle social authentication
• Implement proper session management

Data Management

CRUD Operations

Full-featured CRUD interface examples. Learn how to:

• Build complete data management interfaces
• Implement optimistic updates
• Handle batch operations
• Create responsive data tables
• Manage complex data relationships

Real-time Data

Real-time data synchronization examples. Learn how to:

• Implement WebSocket connections
• Use Server-Sent Events (SSE)
• Set up polling for updates
• Handle real-time notifications
• Build collaborative features

File Operations

File Operations

Complete file handling examples. Learn how to:

• Upload files and images
• Download and manage files
• Process and compress images
• Implement file sharing
• Handle file validation and security

️ Database Integration

Database Queries

Database integration examples. Learn how to:

• Work with SQLite databases
• Integrate with PostgreSQL
• Use MongoDB for document storage
• Implement database migrations
• Handle transactions and data consistency

Getting Started

Each example is designed to be:

• Complete - Full, working code that you can run immediately
• Educational - Clear explanations of concepts and patterns
• Practical - Real-world scenarios you’ll encounter in production
• Progressive - Start simple and build up to complex features

Quick Start

1. Choose an example that matches your use case
2. Copy the code and adapt it to your project
3. Follow the patterns to implement similar features
4. Customize the examples to fit your specific needs

Example Structure

Each example follows a consistent structure:

// 1. Service Layer - API calls and business logic
class ExampleService {
  static Future<Data> fetchData() async {
    // Implementation
  }
}
 
// 2. UI Components - Widgets and screens
class ExampleScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return QueryBuilder<Data>(
      queryKey: 'example-data',
      queryFn: () => ExampleService.fetchData(),
      builder: (context, state) {
        return state.when(
          loading: () => CircularProgressIndicator(),
          error: (error, stack) => Text('Error: $error'),
          data: (data) => DataWidget(data: data),
        );
      },
    );
  }
}
 
// 3. Data Models - Type-safe data structures
class Data {
  final String id;
  final String name;
  
  Data({required this.id, required this.name});
  
  factory Data.fromJson(Map<String, dynamic> json) {
    return Data(id: json['id'], name: json['name']);
  }
}

Best Practices

Throughout the examples, you’ll see these best practices in action:

Query Management

• Use descriptive query keys
• Implement proper error handling
• Cache data appropriately
• Invalidate queries when needed

State Management

• Use optimistic updates for better UX
• Handle loading states gracefully
• Implement proper error recovery
• Manage complex state transitions

Performance

• Optimize API calls and caching
• Implement efficient data structures
• Use appropriate loading indicators
• Minimize unnecessary re-renders

Security

• Validate all inputs
• Handle authentication properly
• Implement proper error messages
• Use secure data storage

Common Patterns

Error Handling

QueryBuilder<List<User>>(
  queryKey: 'users',
  queryFn: () => UserService.getUsers(),
  builder: (context, state) {
    return state.when(
      loading: () => CircularProgressIndicator(),
      error: (error, stack) => ErrorWidget(
        error: error,
        onRetry: () => QueryClient().invalidateQuery('users'),
      ),
      data: (users) => UserList(users: users),
    );
  },
)

Optimistic Updates

MutationBuilder<User, Map<String, String>>(
  mutationFn: (data) => UserService.createUser(data),
  options: MutationOptions(
    onMutate: (data) {
      // Optimistically update cache
      final users = QueryClient().getQueryData<List<User>>('users');
      if (users != null) {
        final optimisticUser = User.fromJson(data);
        QueryClient().setQueryData('users', [...users, optimisticUser]);
      }
    },
    onSuccess: (user) {
      // Invalidate to get fresh data
      QueryClient().invalidateQuery('users');
    },
    onError: (error) {
      // Rollback on error
      QueryClient().invalidateQuery('users');
    },
  ),
  builder: (context, state) {
    return ElevatedButton(
      onPressed: state.isLoading ? null : () {
        state.mutate({'name': 'John', 'email': 'john@example.com'});
      },
      child: state.isLoading ? CircularProgressIndicator() : Text('Create User'),
    );
  },
)

Real-time Updates

class RealTimeUsersScreen extends StatefulWidget {
  @override
  State<RealTimeUsersScreen> createState() => _RealTimeUsersScreenState();
}
 
class _RealTimeUsersScreenState extends State<RealTimeUsersScreen> {
  @override
  void initState() {
    super.initState();
    WebSocketService.connect('ws://localhost:8080/ws');
  }
  
  @override
  void dispose() {
    WebSocketService.disconnect();
    super.dispose();
  }
  
  @override
  Widget build(BuildContext context) {
    return QueryBuilder<List<User>>(
      queryKey: 'users',
      queryFn: () => UserService.getUsers(),
      builder: (context, state) {
        return state.when(
          loading: () => Center(child: CircularProgressIndicator()),
          error: (error, stack) => Center(child: Text('Error: $error')),
          data: (users) => ListView.builder(
            itemCount: users.length,
            itemBuilder: (context, index) {
              final user = users[index];
              return UserTile(user: user);
            },
          ),
        );
      },
    );
  }
}

Next Steps

Ready to dive in? Here are some recommended paths:

For Beginners

1. Start with REST API examples
2. Learn CRUD Operations patterns
3. Explore Authentication flows

For Intermediate Developers

1. Dive into GraphQL integration
2. Implement Real-time Data features
3. Add File Operations to your app

For Advanced Developers

1. Master Database Queries patterns
2. Implement complex CRUD Operations with transactions
3. Build sophisticated Real-time Data collaboration features

Contributing

Found a bug or want to add an example? We’d love your contribution! Check out our Contributing Guide for details.

Support

Need help with an example? Join our community:

• GitHub Discussions - Ask questions and share solutions
• Discord - Real-time chat with the community
• Stack Overflow - Tag your questions with fasq

Happy coding!