如何在异步Azure功能中使用Azure Notification Hub？

Question

I'm attempting to create a Precompiled Azure Function that makes use of an Azure Notification Hub, and I'm having some difficulty getting it to run.

My issue is outlined below.

My steps: 1. Start local development of an Azure Function in Visual Studio. 2. Create an async Function that uses the NotificationHub attribute. For example, here's a simplified version of mine:

[FunctionName("MyFunction")]
    public static async Task Run([TimerTrigger("0 */5 * * * *")]TimerInfo myTimer, 
                                 [NotificationHub]IAsyncCollector<Notification> notification,
                                 TraceWriter log)
    {                                    
        using (var httpClient = new HttpClient())
        {
            try
            {
                // Make several async calls, and create a Windows TileNotification here...
                    await notification.AddAsync(new WindowsNotification(tileContent.GetContent()));
                }                    
            }                
            catch (Exception ex)
            {
                // log failure, etc.
            }
        }
    }

I get the following error message when I attempt to run locally:

Microsoft.Azure.WebJobs.Host: Error indexing method 'MyFunction.Run'.

Microsoft.Azure.WebJobs.Host: Cannot bind parameter 'notification' to type IAsyncCollector`1. Make sure the parameter Type is supported by the binding. If you're using binding extensions (eg ServiceBus, Timers, etc.) make sure you've called the registration method for the extension(s) in your startup code (eg config.UseServiceBus(), config.UseTimers(), etc.).

The documentation has several synchronous examples using out parameters, but no asynchronous examples, and I'm not quite certain what the error message is trying to tell me. Does my NotificationHub attribute need additional configuration? Do I need a functions.json file even though I'm attemtping to use the Precompile Attribute?

Answer 1

As Roman Kiss mentioned that we need to configure notification attribute properties such as ConnectionStringSetting, HubName. For precompiled C# functions, use the NotificationHub attribute , which is defined in NuGet package Microsoft.Azure.WebJobs.Extensions.NotificationHubs .

To configure the binding, add the NotificationHubs namespace connection string as an app setting or environment variable using the setting name AzureWebJobsNotificationHubsConnectionString

public static void Run([TimerTrigger("0 */5 * * * *")]TimerInfo myTimer, [NotificationHub(HubName = "tomnotification", ConnectionStringSetting = "AzureWebJobsNotificationHubsConnectionString")]IAsyncCollector<Notification> notification, TraceWriter log)
    {
        //add you logic
    }

local.settings.json

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "storage connection string",
    "AzureWebJobsDashboard": "storage connection string",
    "AzureWebJobsNotificationHubsConnectionString": "notifiaction hub connection string"
  }
}

Test result: