StartFunction.cs

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// Copyright © Microsoft Corporation.  All Rights Reserved.
// This code released under the terms of the 
// Microsoft Public License (MS-PL, http://opensource.org/licenses/ms-pl.html.)

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;
using Microsoft.Azure.EventGrid;
using Microsoft.Azure.EventGrid.Models;
using System.Collections.Generic;

namespace FunctionFlow.NET
{
    public static class StartFunction
    {
        [FunctionName("StartFunction")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req,
            ILogger log)
        {
            log.LogInformation("StartFunction function processed a request.");
            // get connection details from env
            string topicEndpoint  = Environment.GetEnvironmentVariable("EG_START_EP");
            string topicKey  = Environment.GetEnvironmentVariable("EG_START_KEY");

            // get a connection
            string topicHostname = new Uri(topicEndpoint).Host;
            TopicCredentials topicCredentials = new TopicCredentials(topicKey);
            EventGridClient client = new EventGridClient(topicCredentials);

            // perform initial procssing

            // send message to the next handler
            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            dynamic ddata = JsonConvert.DeserializeObject(requestBody);
            var data = (ddata!=null)?ddata:"i got no message content";
            EventGridEvent mess = GetEvent(data);
            List<EventGridEvent> eventsList = new List<EventGridEvent>();
            eventsList.Add(mess);

            await client.PublishEventsAsync(topicHostname,eventsList);


            string responseMessage = $"sent single message, to this topic: {topicEndpoint}.";

            return new OkObjectResult(responseMessage);
        }

        private static EventGridEvent GetEvent(dynamic data)
        {
            EventGridEvent temp = new EventGridEvent();
            temp.Id = Guid.NewGuid().ToString();
            temp.Data = data;
            temp.Subject = "test1";
            temp.EventTime = DateTime.Now;
            temp.EventType = "Function.Flow.2F1";
            temp.DataVersion = "2.0";
            return temp;
        }

    }
}