HTTP Web Response Exception - I cant able to trap.

prasannavigneshr · #1 (**permalink**) 08-01-2007, 10:04 PM

Hi All

I have a .NET CF v2 program which uses asynchronous HttpWebRequest to download a file. During downloading via GPRS if I press and hold the end call key on my WM 5.0 device to close the GPRS connection, the program will crash. I have tried to place HttpWebResponse.GetResponseStream in a Try/Catch block but it does not catch the exception. On the emulator I cannot reproduce this problem.

This is the error message I get is:

program.exe

SocketExecption

An operation was attempted on something that is not a socket

at System.Net.Sockets.Socket.ReceivedNoCheck()

at System.Net.Sockets.Socket.Receive()

at System.Net.Connection.Read()

at ConnectionClient.Read()

at System.Net.HttpReadStream.NetworkRead()

at System.Net.ContentLengthReadStream.doRead()

at System.Net.HttpReadStream.ReadInternal()

at System.Net.HttpReadStream.Read()

at System.Net.HttpReadStream.doRead()

at WorkItem.doWork()

at System.Threading.Timer.ring()

Is there a way to catch this exception?

Help

naveen · #2 (**permalink**) 08-01-2007, 11:53 PM

Hi, Prasanna

You can debug on your WM5 device(not the emulator), reproduce it and see where it stops, then try/catch the exception.

Regards

Naveen

prasannavigneshr · #3 (**permalink**) 08-01-2007, 11:54 PM

Hi naveen,

Quote:

You can debug on your WM5 device(not the emulator), reproduce it and see where it stops, then try/catch the exception.

Can you tell me how to debug with GPRS? I don't think it is possible!

Debugging with ActiveSync and using my PC to connect to the Internet produces different results.

*
Connecting to the Internet via ActiveSync, debugging is possible. If during downloading midway I close my Internet connection HttpWebResponse returns 0 bytes, no exception is thrown.
*
Connecting to the Internet using GPRS, debugging is not possible. If during downloading midway I close the GRPS connection (press and hold end call key), program crashes. From the error message it seems that the crash is occurring in System.Net.Sockets and not in my code.

Thanks

sandhya · #4 (**permalink**) 08-01-2007, 11:54 PM

You should be able to catch this exception by adding try/catch to your doWork() method.

prasannavigneshr · #5 (**permalink**) 08-02-2007, 02:49 AM

Quote:

You should be able to catch this exception by adding try/catch to your doWork() method.

doWork is in System.Threading.ThreadPool.WorkItem

How can I add try/catch in mscorlib.dll, it's not my code

john · #6 (**permalink**) 08-02-2007, 02:51 AM

Interesting... How come stack trace shows it without namespace?

at System.Net.HttpReadStream.Read()

at System.Net.HttpReadStream.doRead()

at WorkItem.doWork()

at System.Threading.Timer.ring()

If that's not your code it might be a bug in NETCF. You might be able to workaround using AppDomain.CurrentDomain.UnhandledException

prasannavigneshr · #7 (**permalink**) 08-02-2007, 02:52 AM

Thanks John,

I just re-checked to make sure I did not miss something. I can confirm it is reporting:

at WorkItem.doWork()

I do not have any class called WorkItem or any method called doWork. Do you want me to submit a bug to Connect, I should be able to submit some sample code?

I will try AppDomain.CurrentDomain.UnhandledException,
thanks.

john · #8 (**permalink**) 08-02-2007, 02:54 AM

Yes, please go ahead and submit it. I believe you can attach zipped project to the report.

prasannavigneshr · #9 (**permalink**) 08-02-2007, 02:57 AM

Hi john, thanks for your concern,

I have stripped my code to the bare minimum to re-produce the problem, the code is below. Create a new VB. NET project, insert at textbox (TextBox1), label (Label1), and 2 menu items (MenuItem1 and MenuItem2) on the form , then replace the code with the code below. Run program, enter the URL of the file to download in the text box and press MenuItem1 to download.

Once a GPRS connection is estabished and downloading has began, press and hold End Call to close GPRS. The error message I posted earlier will appear.

Code:

Public Class Form1

  Private WithEvents m_dm As New DownloadManager

 

  Private Sub MenuItem2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem2.Click

    m_dm.Abort()

    Me.Close()

  End Sub

 

  Private Sub MenuItem1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem1.Click

    Me.MenuItem1.Enabled = False

    Me.Label1.Text = "Downloading..."

    Me.m_dm.DownloadProduct(Me.TextBox1.Text)

  End Sub

 

  Private m_receivedBytes As Integer

  Private Sub m_downloadService_ProductChuckReceived(ByVal receivedBytes As Integer) Handles m_dm.ProductChuckReceived

    m_receivedBytes = receivedBytes

    Me.Invoke(New EventHandler(AddressOf ProductChuckReceived))

  End Sub

 

  Private Sub ProductChuckReceived(ByVal sender As Object, ByVal e As EventArgs)

    Me.Label1.Text = Convert.ToInt32((m_receivedBytes / m_dm.FileSize) * 100) & "%"

  End Sub

 

  Private Sub m_downloadService_ProductDownloadedCompleted() Handles m_dm.ProductDownloadedCompleted

    Me.Invoke(New EventHandler(AddressOf ProductDownloadedCompleted))

  End Sub

 

  Private Sub ProductDownloadedCompleted(ByVal sender As Object, ByVal e As EventArgs)

    Me.Label1.Text = "Download complete"

  End Sub

End Class

 

Public NotInheritable Class DownloadManager

  Private Const DATA_BLOCK_SIZE As Integer = 65536

  Public Event ProductDownloadedCompleted()

  Public Event ProductChuckReceived(ByVal receivedBytes As Integer)

  Private m_urlRequest As Net.HttpWebRequest = Nothing

  Private m_urlResponse As Net.HttpWebResponse

  Private m_data() As Byte

  Private m_filename As String = ""

  Private m_folder As String = "\"

  Private m_fileSize As Integer

  Private m_fs As IO.FileStream

  Private m_abort As Boolean = False

  Private m_downloading As Boolean = False

  Private m_errMsg As String = ""

 

  Public Sub DownloadProduct(ByVal url As String)

    m_abort = False

    m_filename = "\" & url.Substring(url.LastIndexOf("/"c) + 1)

    m_downloading = True

    m_urlRequest = CType(Net.HttpWebRequest.Create(url), Net.HttpWebRequest)

    m_urlRequest.Timeout = 20000

    m_urlRequest.Method = "GET"

    m_urlRequest.KeepAlive = False

    m_urlRequest.BeginGetResponse(New AsyncCallback(AddressOf ResponseReceived), Nothing)

  End Sub

 

  Private Sub ResponseReceived(ByVal ar As IAsyncResult)

    If m_abort = False Then

    Try

      m_urlResponse = CType(m_urlRequest.EndGetResponse(ar), Net.HttpWebResponse)

      m_data = New Byte(DATA_BLOCK_SIZE) {}

      m_fileSize = Convert.ToInt32(m_urlResponse.ContentLength)

      If IO.File.Exists(m_filename) Then

        IO.File.Delete(m_filename)

      End If

      m_fs = New IO.FileStream(m_filename, IO.FileMode.Create)

      Catch ex As Net.WebException

        m_errMsg = ex.Message

      Catch ex As IO.IOException

        m_errMsg = ex.Message

      End Try

    End If

 

    If m_abort OrElse m_errMsg <> "" Then

    Else

      RaiseEvent ProductChuckReceived(0)

      m_urlResponse.GetResponseStream().BeginRead(m_data, 0, DATA_BLOCK_SIZE, New AsyncCallback(AddressOf OnDataRead), Me)

    End If

  End Sub

 

  Sub OnDataRead(ByVal res As IAsyncResult)

    If m_abort = False Then

      Dim bytesWrite As Integer = m_urlResponse.GetResponseStream().EndRead(res)

      m_fs.Write(m_data, 0, bytesWrite)

      If bytesWrite > 0 Then

        If m_abort = False Then

          RaiseEvent ProductChuckReceived(Convert.ToInt32(m_fs.Position))

        Try

          m_urlResponse.GetResponseStream().BeginRead(m_data, 0, DATA_BLOCK_SIZE, New AsyncCallback(AddressOf OnDataRead), Me)

          Catch ex As Exception

        End Try

      End If

    Else

      If m_fs.Length <> Me.m_fileSize Then

        m_abort = True

        Me.m_errMsg = "Error downloading file."

      End If

      m_urlResponse.Close()

      m_urlRequest.Abort()

      m_urlResponse.GetResponseStream.Close()

      If m_abort = False Then

        m_fs.Close()

        m_fs = Nothing

        RaiseEvent ProductDownloadedCompleted()

      End If

    End If

  End If

  If m_abort Then

    m_fs.Close()

    m_fs = Nothing

    Try

      If IO.File.Exists(m_filename) Then

        IO.File.Delete(m_filename)

      End If

    Catch ex As Exception

    End Try

  End If

End Sub

 

Public Sub Abort()

  m_abort = True

  If m_downloading Then

    m_urlRequest.Abort()

    m_urlRequest = Nothing

    m_urlResponse.Close()

    m_urlResponse = Nothing

  End If

End Sub

 

Public ReadOnly Property FileSize() As Integer

  Get

    Return m_fileSize

  End Get

End Property

 

  Public Function Aborted() As Boolean

    Return m_abort

  End Function

End Class

Thanks buddy,

john · #10 (**permalink**) 08-02-2007, 02:58 AM

Hi,

I wonder what is the version number of NETCF you used? You can find the version number by running cgacutil.exe from the \windows directory.

Cheers,

John

theone · #11 (**permalink**) 08-30-2007, 09:37 AM

Hi all,

I created 2 web services with VB.NET. When I test them in the
automatically-generated aspx page, there's no problem.

However, when I try to call them from a program, I get the following error:
The request failed with HTTP status 401: Access Denied.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information
about the error and where it originated in the code.

Exception Details: System.Net.WebException: The request failed with HTTP
status 401: Access Denied.
--
When I turn on the trace I get this info:
Line 69:
System.Web.Services.Protocols.SoapDocumentMethodAt tribute("http://tempuri.or
g/BrowseDestinations",
Use:=System.Web.Services.Description.SoapBindingUs e.Literal,
parameterstyle:=system.web.services.protocols.soap parameterstyle.wrapped)>
_
Line 70: Public Function BrowseDestinations(ByVal StartDate As
String, ByVal EndDate As String, ByVal Categories As String) As
System.Data.DataSet
-->Line 71: Dim results() As Object =
Me.Invoke("BrowseDestinations", New Object() {StartDate,
EndDate,Categories})
Line 72: Return CType(results(0),System.Data.DataSet)
Line 73: End Function
--
The Line 71 raise the authentication error. This piece of code corresponds
to the proxy that VS.NET generates for the web service.

As you can see this is a security error caused by the automatically-generated
proxy and to be honest with you people, I
would be needing the 'Complete Idiot Guide' to solve it as I'm a newbie when
it comes to set access permitions in Windows 2000.

I have both anonymous access and integrated Windows auth checked for the
web directory hosting my web services.

Do i have to change wy config.web or anything like that?

Thanks in advance for any help

raja · #12 (**permalink**) 08-30-2007, 09:42 AM

I have the exact same problem! I was just doing the walkthrough (Accessing
A Web Service).

theone · #13 (**permalink**) 08-30-2007, 09:42 AM

Try unchecking Integrated Windows Authentication in your Directory Security
settings. It worked for me. : )

suresh · #14 (**permalink**) 08-30-2007, 09:44 AM

I have exactly the same problem. I receive the 401 http error while doing
the walkthrough "Accessing an XML Web Servive using visual Basic or Visual
C#" (I did it with C#).

I tried to uncheck the "Integrated Windows Authentication" option in IIS
but it didn't work!

Here is the error I received from the Web Service:

Server Error in '/TempConvertClient2' Application.
--------------------------------------------------------------------------------

The request failed with HTTP status 401: Access Denied.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information about
the error and where it originated in the code.

Exception Details: System.Net.WebException: The request failed with HTTP
status 401: Access Denied.

Source Error:

Line 35: [System.Web.Services.Protocols.SoapDocumentMethodAt tribute("http://Walkthrough/XmlWebServices/ConvertTemperature",
RequestNamespace="http://Walkthrough/XmlWebServices/", ResponseNamespace="http://Walkthrough/XmlWebServices/",
Use=System.Web.Services.Description.SoapBindingUse .Literal, ParameterStyle=System.Web.Services.Protocols.SoapP arameterStyle.Wrapped)]
Line 36: public System.Double ConvertTemperature(System.Double dFahrenheit)
{
Line 37: object[] results = this.Invoke("ConvertTemperature",
new object[] {
Line 38: dFahrenheit});
Line 39: return ((System.Double)(results[0]));

Source File: c:\inetpub\wwwroot\TempConvertClient2\Web References\ConvertSvc\Reference.cs
Line: 37

Stack Trace:

[WebException: The request failed with HTTP status 401: Access Denied.]
System.Web.Services.Protocols.SoapHttpClientProtoc ol.ReadResponse(SoapClientMessage
message, WebResponse response, Stream responseStream) +1174
System.Web.Services.Protocols.SoapHttpClientProtoc ol.Invoke(String methodName,
Object[] parameters) +216
TempConvertClient2.ConvertSvc.Service1.ConvertTemp erature(Double dFahrenheit)
in c:\inetpub\wwwroot\TempConvertClient2\Web References\ConvertSvc\Reference.cs:37
TempConvertClient2.WebForm1.Button1_Click(Object sender, EventArgs e)
in c:\inetpub\wwwroot\tempconvertclient2\webform1.asp x.cs:54
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +108
System.Web.UI.WebControls.Button.System.Web.UI.IPo stBackEventHandler.RaisePostBackEvent(St ring
eventArgument) +58
System.Web.UI.Page.RaisePostBackEvent(IPostBackEve ntHandler sourceControl,
String eventArgument) +18
System.Web.UI.Page.RaisePostBackEvent(NameValueCol lection postData) +33
System.Web.UI.Page.ProcessRequestMain() +1263

raja · #15 (**permalink**) 08-30-2007, 09:46 AM

You need to set the Credentials property of your service. To pass the
system credentials for the current security context, you can use
CredentialCache.DefaultCredentials.

For a service named SimpleService, it would look something like this:

[C#]
SimpleService ss = new SimpleService();
ss.Credentials = System.Net.CredentialCache.DefaultCredentials;

theone · #16 (**permalink**) 08-30-2007, 09:47 AM

The call to System.Net.CredentialCache.GetCredential by the underlying web
services code will get a null w/o setting the value described below. That
being the case, does anyone know why in every web service example I've seen
this is never mentioned? Adding it works for both WinForm and ASP.NET as
seems to be required in each. Anyone have any background why this is never
mentioned since this is so critical to making web service calls work.

Thanks!

Venkat · #17 (**permalink**) 08-30-2007, 09:52 AM

I have code as follows -

href = "URL"

// Create a request for the URL.

WebRequest request = WebRequest.Create(href);

//Set the USerAgent

((HttpWebRequest)request).UserAgent = "msie";

// Get the response.

WebResponse response = request.GetResponse();

Sometimes the code "WebResponse response = request.GetResponse();" is giving time out error.

Please let me know how can I handle this situation.

santhakumar · #18 (**permalink**) 08-30-2007, 09:54 AM

Catch the exception

It would be more useful to see a complete program. It could be a programming error, or maybe the connection to the remote site is really timing out.

Are you disposing all WebResponse objects?

Venkat · #19 (**permalink**) 08-30-2007, 09:55 AM

This the modified code -

I have chnaged the code still also I am getting the error

// Create a request for the URL.

WebRequest request = WebRequest.Create("URL");

//Add the User Agent

((HttpWebRequest)request).UserAgent = "msie"

//Time out

((HttpWebRequest)request).Timeout = 600000;

//Time out

((HttpWebRequest)request).ReadWriteTimeout = 600000;

//set alive = true

((HttpWebRequest)request).KeepAlive = true;

//auto redirect = true

((HttpWebRequest)request).AllowAutoRedirect = true;

// Get the response.

WebResponse response = request.GetResponse();

I am getting the error in the line - "WebResponse response = request.GetResponse();"

Full program goes as follows -

XmlTextReader xmlTextReader = null;

// Create a request for the URL.

WebRequest request = WebRequest.Create(href);

//Set the USerAgent

((HttpWebRequest)request).UserAgent = ConfigurationSettings.AppSettings["USER_AGENT"].ToString();

//Time out

((HttpWebRequest)request).Timeout = Convert.ToInt32(ConfigurationSettings.AppSettings["URL_TIME_OUT"].ToString());

//Time out

((HttpWebRequest)request).ReadWriteTimeout = Convert.ToInt32(ConfigurationSettings.AppSettings["URL_TIME_OUT"].ToString());

//set alive = true

((HttpWebRequest)request).KeepAlive = true;

//auto redirect = true

((HttpWebRequest)request).AllowAutoRedirect = true;

// Get the response.

WebResponse response = request.GetResponse();

// Get the stream containing content returned by the server.

Stream dataStream = response.GetResponseStream();

//XmlTextReader

xmlTextReader = new XmlTextReader(dataStream);

santhakumar · #20 (**permalink**) 08-30-2007, 09:56 AM

That's just more code, not a program—is that code executed in a loop, is there any exception handling, etc.?

At least, make sure to wrap your code that uses the WebResponse and the response Stream in a C# using block:

Code:

using (WebResponse response = request.GetResponse())

using (Stream responseStream = response.GetResponseStream())

{

    // Read from responseStream

}

Note that if this is all you need to do from a networking perspective, you're better of using System.Net.WebClient, as it shields you from the chores of managing and disposing responses, streams etc.

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