Ex.Microsoft.Azure.ServiceBus.Hosting

Description

Ex.Microsoft.Azure.ServiceBus.Hosting implements the ability to host an application process messages from an Azure Service Bus Queue or Subscription.

Licensing

Released under the MIT License. See the LICENSE File for further details.

Usage

Use the IMessageHandler and IExceptionHandler interfaces in order to implement functionality for processing. The IMessageHandler interface is used for business logic that would normally get processed through the RegisterMessageHandler method. Likewise the IExceptionHandler interface is used for handling any uncaught exceptions.

Processing messages

This sample shows a simple implementation of what IMessageHandler requires.

using Microsoft.Azure.ServiceBus.Hosting;
using System.Threading;
using System.Threading.Tasks;

public class MyMessageHandler : IMessageHandler {
  public Task HandleAsync(Message message, CancellationToken cancellationToken) =>
    throw new NotImplementedException();
}

Processing exceptions

This sample shows a simple implementation of what IExceptionHandler requires.

using Microsoft.Azure.ServiceBus.Hosting;
using System.Threading;
using System.Threading.Tasks;

public class MyExceptionHandler : IExceptionHandler {
  public Task HandleExceptionAsync(ExceptionReceivedEventArgs eventArgs) =>
    throw new NotImplementedException();
}

Connecting to a Service Bus Queue

Use the ConfigureServiceBusQueue extension method to connect to a Service Bus Queue.

using Microsoft.Azure.ServiceBus.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using System.Threading.Tasks;

public static class Program {
  static string GetConnectionString(IConfiguration configuration) =>
    configuration.GetSection("ConnectionStrings")["ServiceBusConnection"];

  public static Task Main(string[] args) =>
    new HostBuilder().ConfigureServiceBusQueue(
      (hostBuilder, options) => 
        options.ConnectionString = GetConnectionString(hostBuilder.Configuration),
      context => context.ExceptionHandler<MyExceptionHandler>()
        .StaticMessageHandler()
        .Scoped<MyMessageHandler>()
    )
    .RunConsoleAsync();
}

Connecting to a Service Bus Subscription

Use the ConfigureServiceBusSubscription extension method to connect to a Service Bus Subscription.

using Microsoft.Azure.ServiceBus.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Hosting;
using System.Threading.Tasks;

public static class Program {
  static string GetConnectionString(IConfiguration configuration) =>
    configuration.GetSection("ConnectionStrings")["ServiceBusConnection"];

  public static Task Main(string[] args) =>
    new HostBuilder().ConfigureServiceBusSubscription(
      (hostBuilder, options) =>
      {
        options.ConnectionString = GetConnectionString(hostBuilder.Configuration);
        options.SubscriptionName = hostBuilder.Configuration["SubscriptionName"];
      },
      context => context.ExceptionHandler<MyExceptionHandler>()
        .StaticMessageHandler()
        .Scoped<MyMessageHandler>()
    )
    .RunConsoleAsync();
}

Handling messages generically

You can also handle messages using IMessageHandler<T>, which creates a contract with a generic type.

public class MyInt32Handler : IMessageHandler<int> {
  public Task HandleAsync(int message, CancellationToken cancellationToken) =>
    throw new NotImplementedException();
}

public class MyStringHandler : IMessageHandler<string> {
  public Task HandleAsync(string message, CancellationToken cancellationToken) =>
    throw new NotImplementedException();
}

public static class Program {
  static string GetConnectionString(IConfiguration configuration) =>
    configuration.GetSection("ConnectionStrings")["ServiceBusConnection"];

  public static Task Main(string[] args) =>
    new HostBuilder().ConfigureServiceBusQueue(
      (hostBuilder, options) =>
        options.ConnectionString = GetConnectionString(hostBuilder.Configuration),
      context => context.ExceptionHandler<MyExceptionHandler>()
        .GenericMessageHandler(msg =>
        {
          switch (msg.ContentType)
          {
            case "int":
              return BitConverter.ToInt32(msg.Body, 0);
            case "string":
              return Encoding.UTF8.GetString(msg.Body);
            default:
              throw new Exception("Invalid message content type");
          }
        })
        .Scoped<int, MyInt32Handler>()
        .Scoped<string, MyStringHandler>()
    )
    .RunConsoleAsync();
}