azure function request body is null on POST

Question

When I send a request to my azure function I am getting the following exception:

Inner exception System.NullReferenceException handled at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw: at AlidadeUtilities.OnUnzipHttpTriggered+d__0.MoveNext (AlidadeUtilities, Version=1.0.0.0, Culture=neutral, PublicKeyToken=nullAlidadeUtilities, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null: C:\tfs\Corolar\Alidade\AlidadeUtilities\DEV\AlidadeUtilities\OnUnzipHttpTriggered\OnUnzipHttpTriggered.csAlidadeUtilities, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null: 26)

Line 26 of my code is:

var requestBody = new StreamReader(req.Body).ReadToEnd();

The surrounding code is:

public static class OnUnzipHttpTriggered
{
    [FunctionName("OnUnzipHttpTriggered")]
    public static async Task<IActionResult> Run(
        [HttpTrigger(AuthorizationLevel.Function, "post", Route = null)] HttpRequest req,
        ILogger log)
    {
        log.LogInformation("C# HTTP trigger function processed a request.");

        var requestBody = new StreamReader(req.Body).ReadToEnd();
        var data = JsonConvert.DeserializeObject<ZipFileMetaData>(requestBody);
        var storageAccount =
        CloudStorageAccount.Parse(Environment.GetEnvironmentVariable("StorageConnectionString"));

What am I doing wrong?

An example request would be a POST with a JSON body.

How could the req.Body be null?

here's the complete error message:

Microsoft.Azure.WebJobs.Host.FunctionInvocationException:
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<ExecuteWithLoggingAsync>d__17.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 293)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<TryExecuteAsync>d__14.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 89)
Inner exception System.NullReferenceException handled at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw:
   at AlidadeUtilities.OnUnzipHttpTriggered+<Run>d__0.MoveNext (AlidadeUtilities, Version=1.0.0.0, Culture=neutral, PublicKeyToken=nullAlidadeUtilities, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null: C:\tfs\ccc\Alidade\AlidadeUtilities\DEV\AlidadeUtilities\OnUnzipHttpTriggered\OnUnzipHttpTriggered.csAlidadeUtilities, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null: 26)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at Microsoft.Azure.WebJobs.Host.Executors.FunctionInvoker`2+<InvokeAsync>d__9.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionInvoker.csMicrosoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 63)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<InvokeAsync>d__25.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 556)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<ExecuteWithWatchersAsync>d__24.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 503)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<ExecuteWithLoggingAsync>d__23.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 439)
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult (System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e)
   at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<ExecuteWithLoggingAsync>d__17.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35Microsoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.csMicrosoft.Azure.WebJobs.Host, Version=3.0.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: 249)

The function accepts both GET and POST requests. GET request have no BODY. — Nkosi, Dec 24 '18 at 20:07
indeed, but i am making a POST request, yet there's a null reference exception — Alex Gordon, Dec 24 '18 at 20:08
https://lh3.googleusercontent.com/-HMlKajbIe7g/XCE87SqVBCI/AAAAAAAABOE/sN4Uyncbo7k_-tWiJ6JPQQUvtnFRuMlaQCHMYCw/s0/Postman_2018-12-24_14-09-19.png — Alex Gordon, Dec 24 '18 at 20:09
check to make sure that the request in teh trigger is in fact a POST. — Nkosi, Dec 24 '18 at 20:09
@Nkosi thank you. i've redeployed deleting the GET completely, also i've updated the question to include the full error message — Alex Gordon, Dec 24 '18 at 20:15
Try this - string requestBody = await new StreamReader(req.Body).ReadToEndAsync(); And also verify the function app url is same to the one displayed in your azure portal and also verify if your function app is enabled. — Baskar Rao, Dec 24 '18 at 20:18
@Baskar when i disabled the function, i got the `403` response 'function is disabled' - so that makes me certain that the URL is correct. i've also made the change that you suggsted - `string requestBody = await new StreamReader(req.Body).ReadToEndAsync();` but that had no impact — Alex Gordon, Dec 24 '18 at 20:22
@l--''''''---------'''''''''''' is that trigger suppose to have a route? — Nkosi, Dec 24 '18 at 20:32
@l--''''''---------'''''''''''' not sure if this would be of interest to you https://stackoverflow.com/a/52748884/5233410 — Nkosi, Dec 24 '18 at 20:57
can you show what you are posting. It may be valid if post is not getting anything as param — Pranav Singh, Dec 26 '18 at 09:48

score 1 · Answer 1 · answered Dec 26 '18 at 04:17

Firs change the request class to HttpRequestMessage instead of just HttpRequest

The body of the message should be read using

var msg = req.Content.ReadAsStringAsync().Result;

There's no direct req.Body that you are tying to access and so you are getting a null reference exception. If you want the message and messageHeaders then deserialize the msg to and you will have both the values.

  class Content{
    public dynamic MessageBody { get; set; }
    public dynamic MessageHeader { get; set; }
  }
  var message = JsonConvert.DeserializeObject<Content>(msg);
  var messageContext = message.MessageHeader;

You can also see the trigger example in docs

Don't do `req.Content.ReadAsStringAsync().Result`this may well lead to a deadlock situatuion — Liam, Aug 20 '20 at 11:33

azure function request body is null on POST

1 Answers1