An attempt to obtain www.responseHeaders cauzes exception

Unity Engine
1

Hi all.
I recently updated my project to unity 2017.1.0p5 and meat strange behaviour.
When i load local file using WWW class and then try to check responseHeaders property of WWW class instance. It throws exception:

ERROR:

NullReferenceException: Object reference not set to an instance of an object
UnityEngine.WWW.get_responseHeaders () (at C:/buildslave/unity/build/Runtime/WebRequestWWW/UWRWWW.cs:158)
TestLocalLoading+<LoadLocalFile>c__Iterator0.MoveNext () (at Assets/Scripts/TestLocalLoading.cs:20)
UnityEngine.SetupCoroutine.InvokeMoveNext (IEnumerator enumerator, IntPtr returnValueAddress) (at C:/buildslave/unity/build/Runtime/Export/Coroutines.cs:17)

SAMPLE CODE:

public class TestLocalLoading : MonoBehaviour
{
    public void TesLoacalLoading()
    {
        StartCoroutine(LoadLocalFile());
    }

    private static IEnumerator LoadLocalFile()
    {
        var filePath = "file://" + Application.dataPath + "/TestLocalLoading.txt";
        var www = new WWW(filePath);

        while (!www.isDone)
            yield return www;

        Debug.LogFormat("www.text: {0}", www.text); // file loaded correctly
        Debug.LogFormat("www.responseHeaders: {0}", www.responseHeaders); // this line produce exception
    }
}

It’s just a simple code to reproduce error.
In Unity 5.3.4p1 all was fine. But since WWW became a wrapper for UnityWebRequest I start getting errors.

2

I’m having the exact same problem with Unity 2017.1.1p3, the previous version 5.4.1p1 that I used doesn’t have this problem. I believe this is a bug in the responseHeaders getter. @sergey-samus since you’ve already have a simple repro, could you please report a bug so that the Unity team can get it fixed?

3

The fix for this bug is on the way (but it will take a while for it go through backporting & release pipeline).
The issue is that since 2017.1 WWW.responseHeaders can return null when there are no headers. This will be fixed soon to return empty dictionary.

4

Is there any patch build that contains a fix for this? Thanks.

5

Not yet.

6

There’s a different issue here as well. In the case reported by sergey, WWW.responseHeaders does not return null, trying to access it throws an exception.

As far as I can tell, accessing WWW.responseHeaders will throw a NullReferenceException if the response body is empty, even if there are response headers.

7

Correct. This is the other bug, a fix is in the pipeline, will come out soon.

8

We’re interested in these fixes as well, thank you

9

We need it too.

10

I’m also interested in a timeline for a fix. This has broken our plugin for all our customers that upgrade to 2017.X.

We tried UnityWebRequest (Unity - Scripting API: UnityWebRequest) and after a quick test here it doesn’t seem to have the same problems obtaining headers.