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c#httpsizewebrequest

C# WebRequest Send Form Data Size Limit

I am trying to send form data in a WebRequest.

The function works fine and returns a 'Success' response stream as expected.

However, If the length of the 'data' variable exceeds past 30,000 characters I am hit with an HTTP 500 error:

Message "The remote server returned an error: (500) Internal Server Error."

enter image description here

Here is my 'Test' function that is sending the data:

 public IActionResult Test()
 {
     var data = "[0].meetingDate=2019-07-17&[0].courseId=9& 
                        [0].raceNumber=1&[0].horseCode=000000500523";

     //THIS MAKES THE REQUEST ERROR BY INCREASING THE SIZE OF THE DATA WHICH THEN GENERATES A ERROR
     for( int i = 0; i < 400; i++)
     {
         data = data + "[0].meetingDate=2019-07-17&[0].courseId=9&[0].raceNumber=1&[0].horseCode=000000500523";
     }
     //////////////////////////

     WebRequest request = WebRequest.Create("https://localhost:44374/HorseRacingApi/Prices/GetPriceForEntries");
     request.Method = "POST";

     if (!string.IsNullOrEmpty(data))
     {
         byte[] dataBytes = Encoding.ASCII.GetBytes(data);

         request.ContentType = "application/x-www-form-urlencoded";
         request.ContentLength = dataBytes.Length;

         using (Stream requestDataStream = request.GetRequestStream())
         {
             requestDataStream.Write(dataBytes, 0, dataBytes.Length);
             requestDataStream.Flush();
         }
     }

     HttpWebResponse response = (HttpWebResponse)request.GetResponse();
     Stream receiveStream = response.GetResponseStream();

     StreamReader readStream = new StreamReader(receiveStream);

     Debug.WriteLine("Response stream received.");

     string responseMsg = readStream.ReadToEnd();

     Debug.WriteLine(responseMsg);

     response.Close();
     readStream.Close();

     return Ok(responseMsg);
 }

And here is my 'GetPriceForEntries' function:

[HttpPost]
[DisableRequestSizeLimit]
[Route("GetPriceForEntries")]
public JsonResult GetPricesForEntries([FromForm] List<JsonEntryKey> Entries, bool? ShowAll)
{
    return Json("Success");
    //return Json(_priceService.GetPriceForEntries(entries));
}

Unfortunately I cannot change how the 'Test' function sends the data. It must remain the same for compatibility as other applications use this function.

Is there a way to increase the size limit a HTTP WebRequest Stream can do or disable the limit?

I am using MVC on the .NET Core btw.

EDIT: Still no luck after adding the following to Web.config:

  <security>
    <requestFiltering>
      <!-- This will handle requests up to 50MB -->
      <requestLimits maxAllowedContentLength="52428800" />
    </requestFiltering>
  </security>

EDIT 2: After further investigation this is the following error I am receiving after reading the WebException response:

        <h1>An unhandled exception occurred while processing the request.</h1>
        <div class="titleerror">InvalidDataException: Form value count limit 1024 exceeded.</div>
            <p class="location">Microsoft.AspNetCore.WebUtilities.FormReader.Append(ref KeyValueAccumulator accumulator)</p>
Solution

  • Fixed using the following piece of code above the function to set the form limit.

            [RequestFormLimits(ValueCountLimit = int.MaxValue)]

    The default limit is 1024.