Describe the bug

I am unable to add the server options as mentioned below because my options require dependency injection. Therefore, I can't use the given example. Moreover, I've had to create my own background service to instantiate the MQTT server.
That gave me some null reference exceptions.

To Reproduce

Steps to reproduce the behavior:

1. Try adding server options with dependencies injected.
2. Notice that the below example can't be used:

startup
    services
        .AddHostedMqttServerWithServices(s =>
        {
            //Can't get ICertificateVaultManagerFactory here from dependency injection, because they are not injected yet. 
            s.WithoutDefaultEndpoint();
        })
        .AddMqttConnectionHandler()
        .AddConnections();

Expected behavior

I should be able to add server options even when there are dependencies that need to be injected.

Code example

To workaround this, I've created my own background service:

    public class MqttBroker : BackgroundService
    {
        private readonly IServiceProvider _services;
        private readonly ILogger<MqttBroker> _logger;
        private ICertificateRepository _certificateRepository;
        private CertVaultManager _mqttCertVault;

        public MqttBroker(IServiceProvider services, ILogger<MqttBroker> logger)
        {
            _services = services;
            _logger = logger;
        }

        public override async Task StartAsync(CancellationToken cancellationToken)
        {
            using var scope = _services.CreateScope();
            _certificateRepository = scope.ServiceProvider.GetRequiredService<ICertificateRepository>();
            _mqttCertVault = scope.ServiceProvider.GetRequiredService<ICertVaultManagerFactory>().MqttCertVault();

            _logger.LogInformation("Starting service");
            await StartMqttServer();
            _logger.LogInformation("Service started");
            await base.StartAsync(cancellationToken);
        }
        
        private async Task StartMqttServer()
        {
          // Certificate setup
          var serverCertificate = ...; // Retrieve server certificate from dependency injection (vault & repository)
          var trustedCaCertificates = ...; // Retrieve trusted CA certificates from dependency injection (vault & repository)

          var optionsBuilder = new MqttServerOptionsBuilder()
              .WithEncryptedEndpoint()
              .WithEncryptedEndpointPort(/*specific port*/)
              .WithEncryptionCertificate(serverCertificate)
              .WithEncryptionSslProtocol(SslProtocols.Tls12)
              .WithClientCertificate(ValidateClientCertificate);

          var mqttServer = new MqttFactory().CreateMqttServer(optionsBuilder.Build());
          mqttServer.WithAttributeRouting(_services, true);
          // Additional setup methods...

          await mqttServer.StartAsync();
}

However, I've had to rely on WithAttributeRouting, which is marked as obsolete now, but it's indispensable in my scenario.

Additionally, when using a custom background service created after the service initialization, the following is always null because it as never been resolved in startup services:

var server = app.ApplicationServices.GetRequiredService<MqttServer>()

I'd like to shed light on two main points:

1. I've started making modifications so that the library works only in my case. HERE the PR
   I removed unecessary

var server = app.ApplicationServices.GetRequiredService<MqttServer>();

2. By doing this it's open a new interogation about singleton MqttRouter
   It would be beneficial to remove this, too make mqttRouter working great with multi mqttServer

services.AddSingleton<MqttRouter>();

because I added server property in MqttRouter class

public MqttServer Server { get; set; }

It means one MqttRouter per MqttServer.

The reason being, I am planning to have multiple instances of mqttServer on a single machine.
For instance, managing two MQTT ports: 8883 and 8884, both with TLS.

Because I might want to run

• port: 8884 with an new CA certificate,
• port: 8883 with a the old Ca certificate

making two distinct server certificates coexist on a single machine.

What do you think about this?

Yeah i need someone to think about this multi/custom hosted mqttServer :P
I hope you will share your thoughts. See you soon.

Hi, i currently have this implementation of the controller:

[MqttController]
[MqttRoute("telemetry")]
public class DeviceTelemetryController: MqttBaseController
{
    public Task NewTelemetry()
    {
        return BadMessage();
    }
}

My question is, how to make the Action async?
Thanks in advance

How to use WithAttributeRouting? I was reading readme and the extension WithAttributeRouting is not there, instead it is

    public static void WithAttributeRouting(
      this MqttServer server,
      IServiceProvider svcProvider,
      bool allowUnmatchedRoutes = false)

How to get the IServiceProvider for this method?

Thanks in advance

Describe the feature request

I would like to be able to more easily do request- and performance logging of the controller methods. One way to generically implement this, could be to add support for an 'route invocation interceptor' that are called before- and after the controller method is invoked in the MqttRouter. This could allow for many different use cases apart from logging.

Describe the solution you'd like

In program.cs I would like the ability to configure .WithRouteInvocationInterceptor() with an type-reference to IRouteInvocationInterceptor that can be resolved via dependency injection.

public interface IRouteInvocationInterceptor {
    /// <summary>
    /// Executed before the route handler is executed
    /// </summary>
    /// <param name="clientId">The identifier of sender of the message</param>
    /// <param name="applicationMessage">The message being handled</param>
    /// <returns>Returns an opague object that may be used to correlate before- and after route execution. May be null</returns>
    Task<object?> RouteExecuting( string clientId, MqttApplicationMessage applicationMessage );
    
    /// <summary>
    /// Executed after the route handler has been executed.
    /// </summary>
    /// <param name="o">Set to the the response of <see cref="RouteExecuting(string, MqttApplicationMessage)"/>. May be null.</param>
    /// <param name="ex">An exception if the route handler failed. Otherwise null.</param>
    /// <returns></returns>
    Task RouteExecuted(object? o, Exception? ex);
}

If the interceptor is configured, it should be called in the MqttRouter.OnIncomingApplicationMessage method.

Describe alternatives you've considered

The alternative, currently, is to add logging to each individual controller method which is tedious and potentially error prone.

Please note

Please note that all names are purely suggestions ;)

Describe the bug

Inside one of the controller Route I'm using this code to send an message to all subscriber
// Now inject the new message at the broker.
await Server.InjectApplicationMessage(new InjectedMqttApplicationMessage(msg)
{
SenderClientId = MqttServerConstants.ClientId
});

But What I found is an error on the Logs saying that the Message will be drop

To Reproduce

Steps to reproduce the behavior:

1. Using this version of MQTTnet 4.X.X

2. Create a controller then send a message using Server.InjectApplicationMessage

3. Make sure you are using:
   app.UseMqttServer(server =>
   {
   server.WithAttributeRouting(app.ApplicationServices, allowUnmatchedRoutes: false);
   });

4. See error.

Expected behavior

A clear and concise description of what you expected to happen.

Need the ability to ignore the Server message from the router
by maybe looking at the sender id

Screenshots

None

Additional context / logging

Using this example
https://github.com/dotnet/MQTTnet/blob/7f5c437c46dd52ecb1d53dfc8ea9fb8ff46caf5d/Samples/Server/Server_Simple_Samples.cs#L53C12-L53C55

dbug: MQTTnet.AspNetCore.Routing.MqttRouter[0]
      Rejecting message publish because 'route/path' did not match any known routes.

This repository seems to be the most actively developed of all forks, so i think there may be a few ways where the library can be improved more.

Describe the feature request

For the routes, i think it will be nice to have something like ASP.NET Core's [Authorize] attribute which client validation method can be specified, and some way to deserialize the json payload in a action parameter decorated with [FromPayload] automatically if Authorize is successful or not present

Describe the solution you'd like

in ASP.NET Core we can have

[Route("{someNumber:int}"]
public async Task<IActionResult> SomeAction(int someNumber, [FromForm] SomeModel viewModel) {
  return Ok();
}

I think it's nice and streamlined way for the part to do stuff in a manner that is very similar to AspNet Core, so I'd imagine something like

[Authorize(Policy = "AuthorizedDevices")]
[MqttRoute("{someNumber:int}"]
public async Task SomeAction(int someNumber, [FromPayload] SomeModel viewModel) {
  // do something
  await Ok();
  return;
}