How to send data to Service Bus Topic with Azure Functions?

Question

I have a default C# based HTTP Trigger here and I wish to send data "Hello Name" to Service Bus Topic (already created). I'm coding in Azure Portal.

How to do it Service Bus output binding?

This is not working. Any help available?

• Reference missing for handling Service Bus?
• How to define Connection of service bus? Where is Functions.json
• How to send a message to service bus?

//This FunctionApp get triggered by HTTP and sends message to Azure Service Bus

using System;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;

namespace Company.Function
{
    public static class HttpTriggerCSharp1
    {
        [FunctionName("HttpTriggerCSharp1")]
        [return: ServiceBus("myqueue", Connection = "ServiceBusConnection")] // I added this for SB Output. Where to define.

        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)] HttpRequest req,
            ILogger log)

        {
            log.LogInformation("C# HTTP trigger function processed a request.");
            string name = req.Query["name"];
            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            dynamic data = JsonConvert.DeserializeObject(requestBody);
            name = name ?? data?.name;
            string responseMessage = string.IsNullOrEmpty(name)
                ? "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response."
                : $"Hello, {name}. This HTTP triggered function executed successfully.";
            return new OkObjectResult(responseMessage);
            // I added this for SB Output
            return responseMessage;
        }
    }
}

Answer 1

There are two bindings to send data to service bus. First is what you show, using the return binding, after installing two packages Microsoft.Azure.WebJobs.Extensions.ServiceBus and WindowsAzure.ServiceBus, then you will be able to send data. And you could not do it cause your function type is IActionResult and you are trying to return a string datatype (responseMessage).

So if you want to send the whole responseMessage, just return new OkObjectResult(responseMessage);, it will work. And the result would be like below image.

And if you want to use return responseMessage; you should change your method type to string, it will be public static async Task<string> RunAsync and result will be below.

Another binding you could refer to below code or this sample.

[FunctionName("Function1")]
[return: ServiceBus("myqueue", Connection = "ServiceBusConnection")]
public static async Task RunAsync(
    [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
    [ServiceBus("myqueue", Connection = "ServiceBusConnection")] MessageSender messagesQueue,
    ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a request.");
        string name = req.Query["name"];
        string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
    dynamic data = JsonConvert.DeserializeObject(requestBody);
    name = name ?? data?.name;
        string responseMessage = string.IsNullOrEmpty(name)
        ? "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response."
        : $"Hello, {name}. This HTTP triggered function executed successfully.";
        byte[] bytes = Encoding.ASCII.GetBytes(responseMessage);
    Message m1 = new Message(bytes);
    await messagesQueue.SendAsync(m1);
    
}

How to define Connection of service bus? Where is Functions.json

In the local you should define the connection in the local.settings.jon, you could use any name with the connection, then in the binding Connection value should be the name you set in the JSON file. And because you are using C#, you could not modify the function.json file - there will be a function.json file in the debug folder. You could only change the binding in the code.

Hope this could help you, if you still have other problem , please feel free to let me know.