Setting up an HTTP endpoint for Azure EventGrid Webhook in my MVS Webapp?

Question

I'm trying to create an Azure Eventgrid and Webhook response to send me inbound text messages from Azure communications services to my Azure hosted WebApp. Right now I'm having a really hard time finding documentation that shows how to create an endpoint within a Webapp controller to get the Azure webhook response to handshake and validate. I've created an endpoint within my controller that I believe should be catching the the data and processing it in a POST method, but it fails because of the arguments I'm trying to mimic. Any insight on this topic is appreciated.

I tried integrating a lot of what I found in these Docs into my app controller to try and get it to work, but I think I might be doing this all the wrong way since it says this code is for an Azure function??? I'm not entirely sure how those are used, but I tried integrating the same C# code into my controller. See Docs below: https://learn.microsoft.com/en-us/azure/event-grid/receive-events

And here is the controller I have that is trying to imitate what I read in the docs I linked

        [HttpPost("incoming")]
    public async Task<IActionResult> GetFlightInfo([HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest incoming,
        ILogger log)
    {
        log.LogInformation("C# HTTP trigger function processed a request.");
        string response = string.Empty;
        BinaryData events = await BinaryData.FromStreamAsync(incoming.Body);
        log.LogInformation($"Received events: {events}");

        EventGridEvent[] egEvents = EventGridEvent.ParseMany(events);

        foreach (EventGridEvent eventGridEvent in egEvents)
        {
            // Handle system events
            if (eventGridEvent.TryGetSystemEventData(out object eventData))
            {
                // Handle the subscription validation event
                if (eventData is SubscriptionValidationEventData subscriptionValidationEventData)
                {
                    log.LogInformation($"Got SubscriptionValidation event data, validation code: {subscriptionValidationEventData.ValidationCode}, topic: {eventGridEvent.Topic}");
                    // Do any additional validation (as required) and then return back the below response

                    var responseData = new SubscriptionValidationResponse()
                    {
                        ValidationResponse = subscriptionValidationEventData.ValidationCode
                    };
                    return new OkObjectResult(responseData);
                }
            }
        }
                return new OkObjectResult(response);
    }

you should consider using the *Azure SignalR Service* for your solution, see my answer in https://stackoverflow.com/questions/57110732/subscribing-to-an-azure-event-grid-topic-directly-from-an-angular-client — Roman Kiss, Aug 12 '21 at 07:44

score 0 · Answer 1 · answered Dec 09 '21 at 13:03

I'd suggest to start by deploying and exploring the Azure Event Grid Viewer sample application according to the Handle SMS events for Delivery Reports and Inbound Messages tutorial. This app is designed to consume any events generated by the Event Grid, including the SMS ones. The app utilizes SignalR, just as @roman-kiss suggests in his answer, to push the events in near real time to the user.

Once you get a good grasp of the whole flow, you can start adjusting the code to match your use case. A good first step would be adjusting the deserialization logic to take advantage of more specific models. You can get the sample JSON models for SMS events here and convert them to C#.

Setting up an HTTP endpoint for Azure EventGrid Webhook in my MVS Webapp?

1 Answers1