README.md

Flowify Examples

This folder contains working examples demonstrating different usage patterns of the Flowify library.

Examples

1. CommandWithResponse

Demonstrates a command that returns a value.

Command: CreateUserCommand - Creates a user and returns the user ID Handler: CreateUserHandler - Processes the command and returns an integer

Run:

cd CommandWithResponse
dotnet run

2. CommandWithoutResponse

Demonstrates a command that doesn't return a value (void).

Command: SendEmailCommand - Sends an email without returning anything Handler: SendEmailHandler - Processes the command with no return value

Run:

cd CommandWithoutResponse
dotnet run

3. Query

Demonstrates a query that retrieves data.

Query: GetUserByIdQuery - Retrieves a user by ID Handler: GetUserByIdHandler - Fetches and returns user data Model: UserModel - The response object

Run:

cd Query
dotnet run

4. Notification

Demonstrates notifications with multiple handlers processing the same event.

Notification: UserCreatedNotification - Event raised when a user is created Handlers:

• SendWelcomeEmailHandler - Sends a welcome email
• UpdateStatisticsDashboardHandler - Updates statistics
• InvalidateCacheHandler - Invalidates relevant caches

Run:

cd Notification
dotnet run

Key Concepts

Commands with Response

Use IRequest<TResponse> when your command needs to return a value:

public record CreateUserCommand(string Name) : IRequest<int>;
public class CreateUserHandler : IRequestHandler<CreateUserCommand, int>
{
    public Task<int> Handle(CreateUserCommand request, CancellationToken cancellationToken)
    {
        // Return the user ID
        return Task.FromResult(userId);
    }
}

Commands without Response

Use IRequest when your command doesn't need to return anything:

public record SendEmailCommand(string To) : IRequest;
public class SendEmailHandler : IRequestHandler<SendEmailCommand>
{
    public Task Handle(SendEmailCommand request, CancellationToken cancellationToken)
    {
        // Just perform the action
        return Task.CompletedTask;
    }
}

Queries

Queries are semantically the same as commands with responses, but represent read operations:

public record GetUserQuery(int Id) : IRequest<UserModel>;

Notifications

Multiple handlers can process the same notification:

public record UserCreatedNotification(int UserId) : INotification;

// Multiple handlers can listen to the same notification
public class Handler1 : INotificationHandler<UserCreatedNotification> { }
public class Handler2 : INotificationHandler<UserCreatedNotification> { }

Setup

All examples follow the same setup pattern:

var services = new ServiceCollection();
services.AddFlowify(typeof(Program).Assembly);

var serviceProvider = services.BuildServiceProvider();
var mediator = serviceProvider.GetRequiredService<IMediator>();

// Use the mediator
await mediator.Send(command);
await mediator.Publish(notification);