Azure Function for sending a simple son payload to an Azure Event Hub

SASTokenFunction01.csx

using System;
using System.Text;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Security.Cryptography;
 
public static void Run(string input, TraceWriter log)
{
  var resourceUri = "contoso.servicebus.windows.net";
  var keyName = "RootManageSharedAccessKey";
  var key = "randomkey"; 

  TimeSpan sinceEpoch = DateTime.UtcNow - new DateTime(1970,1,1);
  var week = 60 * 60 * 24 *7;
  var expiry = Convert.ToString((int)sinceEpoch.TotalSeconds + week);
  string stringToSign = Uri.EscapeDataString(resourceUri) + "\n" + expiry;
  HMACSHA256 hmac = new HMACSHA256(Encoding.UTF8.GetBytes(key));
  var signature = Convert.ToBase64String(hmac.ComputeHash(Encoding.UTF8.GetBytes(stringToSign)));
  var sasToken = $"sr={Uri.EscapeDataString(resourceUri)}&sig={Uri.EscapeDataString(signature)}&se={expiry}&skn={keyName}";

  var eventHubUrl = "https://contoso.servicebus.windows.net/foo/messages";
  var content = "{\"on\":true, \"sat\":254, \"bri\":254, \"hue\":10000}";

  HttpClient Client = new HttpClient();
  Client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("SharedAccessSignature", sasToken);
  var foo = Client.PostAsync(eventHubUrl, new StringContent(content.ToString())).Result;
  log.Info($"result: {foo}");
}