Wrappit 1.1.8

Wrappit

Wrappit is a simple wrapper around RabbitMQ which makes it easier to both send and recieve messages from RabbitMQ.

Note: Currently, Wrappit only supports Topical exchanges with no plans on supporting other types of exchanges.

Usage

Configuration

To use Wrappit, use the following method in the services:

builder.Services.AddWrappit(new WrappitOptions
{
    HostName = "...",
    Port = 1234,
    UserName = "...",
    Password = "...",
    ExchangeName = "...",
    QueueName = "...",
    // Optionally add the following:
    DeliveryLimit = 5,
    DurableQueue = false,
    DurableExchange = false,
    AutoDeleteQueue = true,
});

These options can be ommitted if the following environment variables have been set:

• Wrappit_HostName.
• Wrappit_Port.
• Wrappit_UserName.
• Wrappit_Password.
• Wrappit_ExchangeName.
• Wrappit_QueueName.
• Optional variables:
  • Wrappit_DeliveryLimit. The default is 10. This delivery limit is used when a handle method fails, this prevents infinite requeuing (see the related issue).
  • Wrappit_DurableQueue.
  • Wrappit_DurableExchange.
  • Wrappit_AutoDeleteQueue.

Once all of the environment variables have been set, the following can be done:

builder.Services.AddWrappit();

Listening to events

Listening to a certain event is easy, simply add the [EventListener] and [Handle("Topic")] Attributes. The handle method requires exactly one parameter, which is the Event. This event needs to inherit from the class DomainEvent:

using Wrappit.Messaging;

public class ExampleEvent : DomainEvent 
{
    public string ExampleProperty { get; set; }
}

By default, the DomainEvent class has a CorrelationId and a DateTime property (for debugging messages).

using Wrappit.Attributes;

[EventListener]
public class SimpleListener
{
    [Handle("Demo.Topic")]
    public void Handle(ExampleEvent e)
    {
        Console.WriteLine(e.ExampleProperty);
        Console.WriteLine(e.CorrelationId);
        Console.WriteLine(e.DateTime);
    }
}

It is also possible to use multiple Handlers in the same event listener class. It is also possible to have multiple handlers listen to the same topic, however, if one of these handlers fails the message will be requeued.

To allow complex logic to take place, it is also possible to use dependency injection in the EventListener class:

using Wrappit.Attributes;

[EventListener]
public class DependencyInjectionListener
{
    private readonly IExample _example;

    public DependencyInjectionListener(IExample example)
    {
        _example = example;
    }

    [Handle("Demo.Topic")]
    public void Handle(ExampleEvent @event)
    {
        _example.DoStuff();
    }
}

Lastly, it is also possible for the Handle method to be asynchronous:

[EventListener]
public class AsyncListener
{
    [Handle("Demo.Async")]
    public async Task HandleAsync(ExampleEvent @event)
    {
        await Task.Delay(2000);
        Console.WriteLine(@event.ExampleProperty);
    }
}

Publishing an event

Publishing an event is even easier, simply add the IWrappitPublisher to your constructor. Dependency injection will take care of the rest:

using Wrappit.Messaging;

public class MessageController
{
    private readonly IWrappitPublisher _publisher;

    public MessageController(IWrappitPublisher publisher)
    {
        _publisher = publisher;
    }

    [HttpPost]
    public void Send(string message)
    {
        _publisher.Publish("Demo.Topic", new ExampleEvent { ExampleProperty = message });
    }
}

Bugs?

Please make an issue, I will take a look at it (if time allows).