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Azure Service Bus

Microsoft Azure Service Bus is a fully managed enterprise integration message broker. Service Bus is most commonly used to decouple applications and services from each other, and is a reliable and secure platform for asynchronous data and state transfer.

Azure services can be used in CAP as a message transporter.



For the Service Bus pricing layer, CAP requires "standard" or "advanced" to support Topic functionality.

To use Azure Service Bus as a message transport, you need to install the following package from NuGet:

PM> Install-Package DotNetCore.CAP.AzureServiceBus
Next, add configuration items to the ConfigureServices method of Startup.cs:

public void ConfigureServices(IServiceCollection services)
    // ...

    services.AddCap(x =>
        // x.UseXXX ...

AzureServiceBus Options

The AzureServiceBus configuration options provided directly by the CAP:

ConnectionString Endpoint address string
EnableSessions Enable Service bus sessions bool false
TopicPath Topic entity path string cap
ManagementTokenProvider Token provider ITokenProvider null


When sessions are enabled (see EnableSessions option above), every message sent will have a session id. To control the session id, include an extra header with name AzureServiceBusHeaders.SessionId when publishing events:

ICapPublisher capBus = ...;
string yourEventName = ...;
YourEventType yourEvent = ...;

Dictionary<string, string> extraHeaders = new Dictionary<string, string>();
extraHeaders.Add(AzureServiceBusHeaders.SessionId, <your-session-id>);

capBus.Publish(yourEventName, yourEvent, extraHeaders);

If no session id header is present, the message id will be used as the session id.