Azure - Sending data from IoT Hub to Web App Backend

Question

I'm searching for a solution to get data from the Azure IoT Hub to the backend of a Web App also hosted in Azure which is written in ASP.NET 4.6. It would be best to just receive the raw Json string as fast as possible.

I found others suggesting using Webhooks or Azure functions for a similar purpose but the delay these solutions bring aren't really acceptable. It would be best to just connect directly to the IoT endpoint and get every message as it comes in. Can anybode please point me to the right direction?

Answer 1

You can simply use the EventHub .NET SDK in your web app, connect to the EventHub-compatible endpoint of the IoT Hub and directly consume the events in your app. This has minimal delay and involves no extra components.

How to guide (.NET core but same applies to .NET Framework): https://docs.microsoft.com/en-us/azure/event-hubs/event-hubs-dotnet-standard-getstarted-send#receive-events

var eventProcessorHost = new EventProcessorHost(
            EventHubName,
            PartitionReceiver.DefaultConsumerGroupName,
            EventHubConnectionString,
            StorageConnectionString,
            StorageContainerName);

// Registers the Event Processor Host and starts receiving messages
await eventProcessorHost.RegisterEventProcessorAsync<SimpleEventProcessor>();

Answer 2

The Azure SignalR Service can help to broadcast messages to the Web App instances.

There are no direct integration between the Azure IoT Hub and Azure SignalR Service. Basically you can use two patterns for this integration such as PULL-PUSH and PUSH-PUSH .

The following screen shows these integration patterns:

Note, that the PUSH-PUSH pattern with the Azure Event Grid is suitable for solution when the subscriber (consumer) is not critical for processing events in the order.