如何在代码中设置useUnsafeHeaderParsing

Question

我收到以下异常：

服务器违反了协议。部分 = ResponseHeader 详细信息 = CR 后面必须跟有 LF

从这个问题：

HttpWebRequestError：服务器违反了协议。 Section=ResponseHeader Detail=CR 后必须跟 LF

我知道我需要将 useUnsafeHeaderParsing 设置为 True。

这是我的代码：

HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(url);
WebResponse myResp = myReq.GetResponse(); //exception is thrown here

useUnsafeHeaderParsing 是 HttpWebRequestElement 类的属性。

如何将其集成到上面的代码中？

Answer 1

您需要在 web.config 的 部分中进行设置，如下所示：

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

如果出于某种原因，您不想从配置中执行此操作，您可以通过以编程方式设置配置设置，从代码中完成此操作。请参阅此页面 举个例子。

Answer 2

正如 Edwin 指出的，您需要在 web.config 或 app.config 文件中设置 useUnsafeHeaderParsing 属性。如果您确实想在运行时动态更改该值，则必须求助于反射，因为该值隐藏在 System.Net.Configuration.SettingsSectionInternal 实例中并且无法公开访问。

这是一个代码示例（基于找到的信息

using System;
using System.Net;
using System.Net.Configuration;
using System.Reflection;

namespace UnsafeHeaderParsingSample
{
    class Program
    {
        static void Main()
        {
            // Enable UseUnsafeHeaderParsing
            if (!ToggleAllowUnsafeHeaderParsing(true))
            {
                // Couldn't set flag. Log the fact, throw an exception or whatever.
            }

            // This request will now allow unsafe header parsing, i.e. GetResponse won't throw an exception.
            var request = (HttpWebRequest) WebRequest.Create("http://localhost:8000");
            var response = request.GetResponse();

            // Disable UseUnsafeHeaderParsing
            if (!ToggleAllowUnsafeHeaderParsing(false))
            {
                // Couldn't change flag. Log the fact, throw an exception or whatever.
            }

            // This request won't allow unsafe header parsing, i.e. GetResponse will throw an exception.
            var strictHeaderRequest = (HttpWebRequest)WebRequest.Create("http://localhost:8000");
            var strictResponse = strictHeaderRequest.GetResponse();
        }

        // Enable/disable useUnsafeHeaderParsing.
        // See http://o2platform.wordpress.com/2010/10/20/dealing-with-the-server-committed-a-protocol-violation-sectionresponsestatusline/
        public static bool ToggleAllowUnsafeHeaderParsing(bool enable)
        {
            //Get the assembly that contains the internal class
            Assembly assembly = Assembly.GetAssembly(typeof(SettingsSection));
            if (assembly != null)
            {
                //Use the assembly in order to get the internal type for the internal class
                Type settingsSectionType = assembly.GetType("System.Net.Configuration.SettingsSectionInternal");
                if (settingsSectionType != null)
                {
                    //Use the internal static property to get an instance of the internal settings class.
                    //If the static instance isn't created already invoking the property will create it for us.
                    object anInstance = settingsSectionType.InvokeMember("Section",
                    BindingFlags.Static | BindingFlags.GetProperty | BindingFlags.NonPublic, null, null, new object[] { });
                    if (anInstance != null)
                    {
                        //Locate the private bool field that tells the framework if unsafe header parsing is allowed
                        FieldInfo aUseUnsafeHeaderParsing = settingsSectionType.GetField("useUnsafeHeaderParsing", BindingFlags.NonPublic | BindingFlags.Instance);
                        if (aUseUnsafeHeaderParsing != null)
                        {
                            aUseUnsafeHeaderParsing.SetValue(anInstance, enable);
                            return true;
                        }

                    }
                }
            }
            return false;
        }
    }
}

Answer 3

如果您不想使用反射，您可以尝试以下代码（System.Configuration.dll参考）：

using System.Configuration;
using System.Net.Configuration;

var config = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);
var settings = (SettingsSection)config.GetSection("system.net/settings");
settings.HttpWebRequest.UseUnsafeHeaderParsing = true;
config.Save(ConfigurationSaveMode.Modified);
ConfigurationManager.RefreshSection("system.net/settings");