The server committed a protocol violation. Section=ResponseStatusLine

Switching off header validation in .NET

Recently I was adding GitHub project section to my blog when I run into the following exception "The server committed a protocol violation. Section=ResponseStatusLine"

After some time of Google-ing I found few solutions, but the most simplest one was actually the best one. Apparently, I needed to switch off request header parsing.

<system.net>
<settings>
<httpWebRequest useUnsafeHeaderParsing = "true"/>
</settings>
</system.net>  

This worked for my problem when pulling GitHub API JSON feed, but I wanted to dig in and figure out what is this setting really doing (except solving my problem out of the box).

I checked Microsoft's online documentation on MSDN and it turns out that HttpWebRequest and HttpWebResponse are doing a bunch of stuff aside from pulling the content on demand.

I went one step further and tried to achieve this switching off from the code. However this value will be used in a request directly from config, so it is not accessible on the request instance level.

After some time Google-ing, I found a method which is doing this with reflection on .NET configuration class instance.

        public static bool SetAllowUnsafeHeaderParsing(bool value)
        {
            //Get the assembly that contains the internal class
            Assembly aNetAssembly = Assembly.GetAssembly(typeof(System.Net.Configuration.SettingsSection));
            if (aNetAssembly != null)
            {
                //Use the assembly in order to get the internal type for the internal class
                Type aSettingsType = aNetAssembly.GetType("System.Net.Configuration.SettingsSectionInternal");
                if (aSettingsType != null)
                {
                    //Use the internal static property to get an instance of the internal settings class.
                    //If the static instance isn't created allready the property will create it for us.
                    object anInstance = aSettingsType.InvokeMember("Section",
                      BindingFlags.Static | BindingFlags.GetProperty | BindingFlags.NonPublic, null, null, new object[] { });

                    if (anInstance != null)
                    {
                        //Locate the private bool field that tells the framework is unsafe header parsing should be allowed or not
                        FieldInfo aUseUnsafeHeaderParsing = aSettingsType.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic | BindingFlags.Instance);
                        if (aUseUnsafeHeaderParsing != null)
                        {
                            aUseUnsafeHeaderParsing.SetValue(anInstance, value);
                            return true;
                        }
                    }
                }
            }
            return false;
        }
    

Original code URL is listed in the references list.

References

• http://msdn.microsoft.com/en-us/library/system.net.configuration.httpwebrequestelement.useunsafeheaderparsing(v=vs.110).aspx
• https://social.msdn.microsoft.com/Forums/en-US/ff098248-551c-4da9-8ba5-358a9f8ccc57/how-do-i-enable-useunsafeheaderparsing-from-code-net-20?forum=netfxnetcom

Disclaimer

Purpose of the code contained in snippets or available for download in this article is solely for learning and demo purposes. Author will not be held responsible for any failure or damages caused due to any other usage.

About the author

DEJAN STOJANOVIC

Dejan is a passionate Software Architect/Developer. He is highly experienced in .NET programming platform including ASP.NET MVC and WebApi. He likes working on new technologies and exciting challenging projects

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