IIS Express 8 - Max allowed length

Question

In case the below is too long, my question is whether IIS Express 8 in Visual Studio 2013 obeys the maxAllowedContentLength attribute or if it has some overriding value that prevents large requests

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When debugging some webapi calls against Visual Studio 2013, I'm receiving this error:

Maximum request length exceeded.

I searched the internet and everything seems to be pointing to these two config entries:

IIS 6-: maxRequestLength
IIS 7+: maxAllowedContentLength

I've added both these config entries to my web.config with a value of 4294967295, just to be safe. When I try to make the call to the controller, I still receive the error.

This made me think that I was sending some gigantic amount of data to the server, but fiddler tells me this:

Request Count:   1
Bytes Sent:      4,327,084      (headers:1,026; body:4,326,058)
Bytes Received:  3,808      (headers:434; body:3,374)

And seeing as how, 4,327,084 < 4,294,967,295 I feel like there shouldn't be any problems with this request.

The next place I thought of looking is my server code:

if (!Request.Content.IsMimeMultipartContent())
{
    throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
}

var provider = new MultipartFormDataStreamProvider(@"C:\tmp", Int32.MaxValue);

var task = Request.Content.ReadAsMultipartAsync(provider).ContinueWith(t =>
{
    if (t.IsFaulted || t.IsCanceled)
        throw t.Exception;   // <== This gets thrown

So once again, the size of the request is significantly less than the buffer size for the data stream provider.

So in summary, I have no idea what's going on. The request is fairly big, but from what I can tell, there's no reason this should be failing. Is this caused by VS13/IIS Exp8? Or is there something else I'm missing?

Thanks in advance for any help you can offer.

---

Here's the config entry I said I would provide

<requestLimits maxAllowedContentLength="4294967295" />

---

And here's the full exception

System.IO.IOException: Error reading MIME multipart body part. ---> System.Web.HttpException: Maximum request length exceeded.
   at System.Web.HttpBufferlessInputStream.ValidateRequestEntityLength()
   at System.Web.HttpBufferlessInputStream.GetPreloadedContent(Byte[] buffer, Int32& offset, Int32& count)
   at System.Web.HttpBufferlessInputStream.BeginRead(Byte[] buffer, Int32 offset, Int32 count, AsyncCallback callback, Object state)
   at System.IO.Stream.<BeginEndReadAsync>b__d(Stream stream, ReadWriteParameters args, AsyncCallback callback, Object state)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncTrim[TInstance,TArgs](TInstance thisRef, TArgs args, Func`5 beginMethod, Func`3 endMethod)
   at System.IO.Stream.BeginEndReadAsync(Byte[] buffer, Int32 offset, Int32 count)
   at System.IO.Stream.ReadAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken)
   at System.Web.Http.WebHost.SeekableBufferedRequestStream.<ReadAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at System.Net.Http.HttpContentMultipartExtensions.<MultipartReadAsync>d__8.MoveNext()
   --- End of inner exception stack trace ---
   at System.Net.Http.HttpContentMultipartExtensions.<MultipartReadAsync>d__8.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   at System.Net.Http.HttpContentMultipartExtensions.<ReadAsMultipartAsync>d__0`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at BICWeb.webservices.controllers.FormsDesignerController.<Post>d__b.MoveNext() in c:\code\BIC_CORE\TRUNK\BIC\src\BICWeb\webservices\controllers\FormsDesignerController.cs:line 300

---

And the inner exception

System.Web.HttpException (0x80004005): Maximum request length exceeded.
   at System.Web.HttpBufferlessInputStream.ValidateRequestEntityLength()
   at System.Web.HttpBufferlessInputStream.GetPreloadedContent(Byte[] buffer, Int32& offset, Int32& count)
   at System.Web.HttpBufferlessInputStream.BeginRead(Byte[] buffer, Int32 offset, Int32 count, AsyncCallback callback, Object state)
   at System.IO.Stream.<BeginEndReadAsync>b__d(Stream stream, ReadWriteParameters args, AsyncCallback callback, Object state)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncTrim[TInstance,TArgs](TInstance thisRef, TArgs args, Func`5 beginMethod, Func`3 endMethod)
   at System.IO.Stream.BeginEndReadAsync(Byte[] buffer, Int32 offset, Int32 count)
   at System.IO.Stream.ReadAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken)
   at System.Web.Http.WebHost.SeekableBufferedRequestStream.<ReadAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at System.Net.Http.HttpContentMultipartExtensions.<MultipartReadAsync>d__8.MoveNext()

Answer 1

just a thought but from: http://www.smarterasp.net/support/kb/a1544/how-to-resolve-maximum-request-length-exceeded.aspx

"maxAllowedContentLength is measured in bytes while maxRequestLength is measured in kilobytes"

check they're both set correctly and try again

Answer 2

Let's look at the code that throws:

private void ValidateRequestEntityLength()
{
    if (!this._disableMaxRequestLength && (this.Length > this._maxRequestLength))
    {
        if (!(this._context.WorkerRequest is IIS7WorkerRequest))
        {
            this._context.Response.CloseConnectionAfterError();
        }
        throw new HttpException(SR.GetString("Max_request_length_exceeded"), null, 0xbbc);
    }
}

The ctor sets those options:

internal HttpBufferlessInputStream(HttpContext context, bool persistEntityBody, bool disableMaxRequestLength)
{
    this._context = context;
    this._persistEntityBody = persistEntityBody;
    this._disableMaxRequestLength = disableMaxRequestLength;
    HttpRuntimeSection httpRuntime = RuntimeConfig.GetConfig(this._context).HttpRuntime;
    this._maxRequestLength = httpRuntime.MaxRequestLengthBytes;
    this._fileThreshold = httpRuntime.RequestLengthDiskThresholdBytes;
    if (this._persistEntityBody)
    {
        this._rawContent = new HttpRawUploadedContent(this._fileThreshold, this._context.Request.ContentLength);
    }
    int contentLength = this._context.Request.ContentLength;
    this._remainingBytes = (contentLength > 0) ? contentLength : 0x7fffffff;
    this._length = contentLength;
}

And you can use this HttpRequest function to disable the limit:

public Stream GetBufferlessInputStream(bool disableMaxRequestLength)
{
    return this.GetInputStream(false, disableMaxRequestLength);
}

If you want to know how the byte limit is being computed, decompile httpRuntime.MaxRequestLengthBytes.