HttpClient 요청에서 IOException 발생

HttpClient 요청에서 IOException 발생

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다음 코드는 "지정된 레지스트리 키가 없습니다."라는 메시지와 함께 IOException을 발생시킵니다.

HttpClient client = new HttpClient();

Uri uri = new Uri("http://www.google.com");

client.GetAsync(uri);

이것은 Main의 콘솔 앱에 있습니다. mscorlib.dll에서 오류가 발생한 것 같습니다! Microsoft.Win32.RegistryKey.Win32Error (int errorCode, string str). 이 오류가 발생하는 이유 또는 디버깅을 시작하는 방법을 모르겠습니다.

스택 추적 편집 :

Microsoft.Win32.RegistryKey.Win32Error (Int32 errorCode, String str)

한 줄 뿐이고 내부 예외 등이 없습니다.

호출 스택은 다음과 같습니다.

mscorlib.dll!Microsoft.Win32.RegistryKey.Win32Error(int errorCode, string str) + 0x189 bytes    
mscorlib.dll!Microsoft.Win32.RegistryKey.GetValueKind(string name) + 0x7f bytes 
System.dll!System.Net.HybridWebProxyFinder.InitializeFallbackSettings() + 0x9e bytes    
[Native to Managed Transition]  
[Managed to Native Transition]  
System.dll!System.Net.AutoWebProxyScriptEngine.AutoWebProxyScriptEngine(System.Net.WebProxy proxy, bool useRegistry) + 0xd0 bytes   
System.dll!System.Net.WebProxy.UnsafeUpdateFromRegistry() + 0x2c bytes  
System.dll!System.Net.Configuration.DefaultProxySectionInternal.DefaultProxySectionInternal(System.Net.Configuration.DefaultProxySection section) + 0x1d8 bytes 
System.dll!System.Net.Configuration.DefaultProxySectionInternal.GetSection() + 0xec bytes   
System.dll!System.Net.WebRequest.InternalDefaultWebProxy.get() + 0xcc bytes 
System.dll!System.Net.HttpWebRequest.HttpWebRequest(System.Uri uri, System.Net.ServicePoint servicePoint) + 0xdf bytes  
System.dll!System.Net.HttpWebRequest.HttpWebRequest(System.Uri uri, bool returnResponseOnFailureStatusCode, string connectionGroupName, System.Action<System.IO.Stream> resendRequestContent) + 0x2b bytes  
System.Net.Http.dll!System.Net.Http.HttpClientHandler.CreateAndPrepareWebRequest(System.Net.Http.HttpRequestMessage request) + 0x59 bytes   
System.Net.Http.dll!System.Net.Http.HttpClientHandler.SendAsync(System.Net.Http.HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) + 0xf4 bytes  
System.Net.Http.dll!System.Net.Http.HttpMessageInvoker.SendAsync(System.Net.Http.HttpRequestMessage request, System.Threading.CancellationToken cancellationToken) + 0x4f bytes 
System.Net.Http.dll!System.Net.Http.HttpClient.SendAsync(System.Net.Http.HttpRequestMessage request, System.Net.Http.HttpCompletionOption completionOption, System.Threading.CancellationToken cancellationToken) + 0x13e bytes 
System.Net.Http.dll!System.Net.Http.HttpClient.GetAsync(System.Uri requestUri, System.Net.Http.HttpCompletionOption completionOption) + 0xc bytes   

ConsoleServiceTest.exe!ConsoleServiceTest.Program.Main(string[] args) Line 20 + 0x17 bytes  C#
    [Native to Managed Transition]  
    [Managed to Native Transition]  
    Microsoft.VisualStudio.HostingProcess.Utilities.dll!Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() + 0x5a bytes  
    mscorlib.dll!System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx) + 0x285 bytes 
    mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool preserveSyncCtx) + 0x9 bytes   
    mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state) + 0x57 bytes    
    mscorlib.dll!System.Threading.ThreadHelper.ThreadStart() + 0x51 bytes   
    [Native to Managed Transition]  

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이는 .NET Framework에 대한 최신 보안 업데이트 : MS12-074 : .NET Framework의 취약점으로 인한 원격 코드 실행 문제로 인한 것 같습니다 : 2012 년 11 월 13 일 (KB 2745030)

웹 프록시 확인에서 모두 다음 코드로 요약됩니다.

[RegistryPermission(SecurityAction.Assert, Read=@"HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework")]
private static void InitializeFallbackSettings()
{
    allowFallback = false;
    try
    {
        using (RegistryKey key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\.NETFramework"))
        {
            try
            {
                if (key.GetValueKind("LegacyWPADSupport") == RegistryValueKind.DWord)
                {
                    allowFallback = ((int) key.GetValue("LegacyWPADSupport")) == 1;
                }
            }
            catch (UnauthorizedAccessException)
            {
            }
            catch (IOException)
            {
            }
        }
    }
    catch (SecurityException)
    {
    }
    catch (ObjectDisposedException)
    {
    }
}

As you can see it checks for a specific registry key mentioned in the KB article. Also you should note that the exception is caught internally, but you see it because you have enabled First Chance Exceptions in the debug options of Visual Studio.

If you want to not see this exception you should add the specified registry key with value 0:

Registry location: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework  
DWORD (32-bit) Value name: LegacyWPADSupport
Value data: 0

and for 32-bit processes on 64-bit machines:

Registry location: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NETFramework
DWORD (32-bit) Value name: LegacyWPADSupport
Value data: 0

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I agree with Ligaz's answer, and I've logged a Connect issue about this bug: https://connect.microsoft.com/VisualStudio/feedback/details/773666/webrequest-create-eats-an-ioexception-on-the-first-call#details

Save the following into a .reg file and import it into the registry to prevent this error from being raised:

Windows Registry Editor Version 5.00

; The following value prevents an IOException from being thrown and caught
; by System.Net.HybridWebProxyFinder.InitializeFallbackSettings() (in System.dll)
; when WebRequest.Create is first called.  By default the "LegacyWPADSupport"
; value doesn't exist, and when InitializeFallbackSettings calls GetValueKind,
; an IOException is thrown.  This adds the value with its default of false to
; prevent the exception.
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework]
"LegacyWPADSupport"=dword:00000000

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NETFramework]
"LegacyWPADSupport"=dword:00000000

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For whatever reason, your HttpClient code is looking for proxy settings in the registry and cannot open the key. A look through the code shows that it attempts to open HKCU and then go to one of the following keys in order:

1. "HKCU\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Internet Settings\\Connections"
2. "HKLM\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Internet Settings\\Connections"
3. "HKLM\\SOFTWARE\\Policies\\Microsoft\\Windows\\CurrentVersion\\Internet Settings"

One of these three is potentially the key your process has no access to, why I am not sure. One possible fix is to disable Automatically Detect Proxy Settings.

Otherwise, you'll need to figure out exactly what key it is loading and we'll do that with two steps.

1. Enable System.Net logging.
2. Download and run Procmon, filtering on registry access for your application, like so:

1. Once opened, disable capturing if enabled (the magnifying glass should have a red X through it).
2. Start filtering on your processes name.
3. Unselect all options except Registry Entries

4. Enable capturing (click the magnifying glass)
5. Run your application
6. Find the offending entry in the log, double click to see which key it was opening

Once you determine the offending key, you can work to figure out why your application does not have access to it. Perhaps, if the name of your application is any indication, the user account your service is running under lacks access to the registry key.

참고URL : https://stackoverflow.com/questions/13141434/httpclient-request-throws-ioexception