Configuring the endpoint
The sample configures an endpoint to use externally managed mode with Microsoft's dependency injection container and registers some dependencies.
// ServiceCollection is provided by Microsoft.Extensions.DependencyInjection
var serviceCollection = new ServiceCollection();
// most dependencies may now be registered
serviceCollection.AddSingleton<Greeter>();
serviceCollection.AddSingleton<MessageSender>();
// EndpointWithExternallyManagedContainer.Create accepts an IServiceCollection,
// which is inherited by ServiceCollection
var endpointWithExternallyManagedContainer = EndpointWithExternallyManagedContainer
.Create(endpointConfiguration, serviceCollection);
// if IMessageSession is required as dependency, it may now be registered
serviceCollection.AddSingleton(p => endpointWithExternallyManagedContainer.MessageSession.Value);
Injecting dependencies into handlers
Registered dependencies may be injected into message handlers using constructor injection:
public class MyHandler :
IHandleMessages<MyMessage>
{
private readonly Greeter greeter;
public MyHandler(Greeter greeter) =>
this.greeter = greeter;
public Task Handle(MyMessage message, IMessageHandlerContext context)
{
greeter.SayHello();
return Task.CompletedTask;
}
}
Injecting the message session into other types
When IMessageSession has been registered as shown above, it may be injected into other types using constructor injection:
public class MessageSender
{
private readonly IMessageSession messageSession;
public MessageSender(IMessageSession messageSession) =>
this.messageSession = messageSession;
public Task SendMessage()
{
var myMessage = new MyMessage();
return messageSession.SendLocal(myMessage);
}
}
An
IMessageSession may only be injected by the container after the endpoint has been started.