How to get connection ID for Web PubSub

Question

I am looking at the C# example for publishing messages here: https://learn.microsoft.com/en-us/azure/azure-web-pubsub/tutorial-pub-sub-messages?tabs=csharp#publish-messages-using-service-sdk

The sample uses SendToAllAsync() but I would like to use SendToConnectionAsync(), however I am not sure how to get the connection id. I have opened the live trace tool and see that a connection ID gets logged when the WebsocketClient connects (from this sample: https://learn.microsoft.com/en-us/azure/azure-web-pubsub/tutorial-pub-sub-messages?tabs=csharp#set-up-the-subscriber).

I can take this connection ID and pass it to SendToConnectionAsync() and it works fine but I don't know where to get the connection id programmatically instead of having to copy and paste it from the live trace tool.

Answer 1

There are several ways to get the connection ID:

1. For the client connection itself, when using the subprotocol, the client receives a connected message once it is connected, which contains the connection Id: https://learn.microsoft.com/azure/azure-web-pubsub/reference-json-webpubsub-subprotocol#connected
2. For the upstream server side, when the events are triggered, it contains the connectionId in the request header as ce-connectionId, a sample usage about register upstream event handlers and fetch headers using sharp is here: https://learn.microsoft.com/en-us/azure/azure-web-pubsub/tutorial-build-chat?tabs=csharp

Could you elaborate more about your scenario when you want to SendToConnectionAsync?