Can no longer get response from HttpWebRequest when 400 returned at Unity 2020,2021

[gguolinegames]

I recently upgraded Unity Version to 2020.3.14f1
then my web request routine cannot get webrequest’s response body when request code is 400 (BadRequest)

It was working fine with Unity 2018,Unity 2019.
but not working with Unity 2020.3.0f1,2020.3.14f1,2021.1.15f1

It crashed when I read WebException’s response stream.

 IAsyncResult asyncResult = httpWebRequest.BeginGetResponse( new AsyncCallback( (IAsyncResult iarres) => {
                string resultText = "";
                System.Net.HttpStatusCode code = 0;
                try
                {                 
                    using ( System.Net.HttpWebResponse response = (System.Net.HttpWebResponse)httpWebRequest.EndGetResponse( iarres ) )
                    {
                        using ( System.IO.StreamReader streamReader = new System.IO.StreamReader( response.GetResponseStream() ) )
                        {
                            resultText = streamReader.ReadToEnd();
                        }
                        code = response.StatusCode;              
                        response.Close();
                    }
                }
                catch ( WebException ex )
                {                 
                    if ( ex.Status == WebExceptionStatus.ProtocolError )
                    {              
                        using ( var stream = ex.Response.GetResponseStream() )
                        {                  
                            using ( System.IO.StreamReader streamReader = new StreamReader( stream ) )
                            {
                                resultText = streamReader.ReadToEnd();  // Crashed at this line.                           
                            }
                            code = ((HttpWebResponse)ex.Response).StatusCode;                                                    
                            ex.Response.Close();
                        }                     
                        return;
                    }
                 
                }
}

It’s almost same issue described at below links

https://stackoverflow.com/questions/55463460/can-no-longer-get-response-from-web-request-when-400-returne

https://github.com/mono/mono/issues/10645

Any help will be appreciated!

Thanks!

[Kurt-Dekker]

Networking, UnityWebRequest, WWW, Postman, curl, WebAPI, etc:

Using Unity for subscription lists

As with all network code, get it working with Postman or curl first. That makes it NOT a Unity problem. Solve the networking first. You must solve that or anything else is irrelevant. Once you have that working, then try and port it to UnityWebRequest. If it still doesn't work, one handy debug solution is to hook up a proxy like Charles and compare the functioning output from Postman / curl to the output from Unity, and from that reason about where your issues are.

Unity web request acting stupid.

Always get network stuff working outside of Unity in either curl or PostMan, then connect a proxy such as Charles and start trying to replicate the traffic shape with UnityWebRequest. Any other way risks wasting a lot of your time for trivial issues that only the above way will instantly reveal.

And setting up a proxy can be very helpful too, in order to compare traffic:

Using Charles Proxy with Unity

[gguolinegames]

@Kurt-Dekker

Networking, UnityWebRequest, WWW, Postman, curl, WebAPI, etc:

https://discussions.unity.com/t/831681/2

https://discussions.unity.com/t/837672/2

And setting up a proxy can be very helpful too, in order to compare traffic:

https://support.unity.com/hc/en-us/articles/115002917683-Using-Charles-Proxy-with-Unity

I tried postman and curl and all these worked well.

Anyway Thanks for response!