Front Controller Pattern/URL Rewriting - Invalid Viewstate

nikolaiblackie

With our web applications we have implemented a front controller/URL rewriting ISAPI DLL that will take URLs like http://yoursite/personedetails and automatically redirect to the actual page i.e. http://yoursite/pages/personedetails.aspx

I am attempting to create a script but I keep getting "Authentication of viewstate failed." errors. I have read in the forums that you need to specify an ASPX page for each request. Is this the case or are there any other ways around this requirement?

nikolaiblackie

My script is pretty simple, it GETS the login page, then POSTS. When I review the IIS logs I see that it always throws a 500 on the POST. I added logging to the script and both values are null. I am assuming this maybe something to do with having no page extentions on request paths

WebClient.HttpRequest.ProtocolVersion = "HTTP/1.1"
BeginPage("http://localhost/")
WebClient.HttpRequest.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; InfoPath.1; .NET CLR 1.0.3705; ANTSLOAD)"
WebClient.HttpRequest.Headers.Set("UA-CPU", "x86")
WebClient.Get("http://localhost/")
EndPage("http://localhost/")
' End of page 1 contains 1 request(s)

Me.LogToFile(WebClient.ViewState) 'returns null
Me.LogToFile(WebClient.HttpResponse.Location) 'returns null

Sleep(7531)
BeginPage("http://localhost/")
WebClient.HttpRequest.Pragma = "no-cache"
WebClient.HttpRequest.ContentType = "application/x-www-form-urlencoded"
WebClient.HttpRequest.AddPostData("__EVENTTARGET", "Login1%3A_ctl0%3A_ctl7", False)
WebClient.HttpRequest.AddPostData("__EVENTARGUMENT", "", False)
WebClient.HttpRequest.AddPostData("__VIEWSTATE", WebClient.ViewState, False)
WebClient.HttpRequest.AddPostData("Login1%3A_ctl0%3A_ctl3", "USERLOGINNAME", False)
WebClient.HttpRequest.AddPostData("Login1%3A_ctl0%3A_ctl5", "USERPASSWORD", False)
WebClient.Post("http://localhost/")
WebClient.HttpRequest.ContentType = Nothing
WebClient.Get("http://localhost/")
EndPage("http://localhost/")
' End of page 2 contains 2 request(s).

Brian Donahue

Hi,

More than likely the problem has more to do with ANTS Load not following redirects (by design). What you want to do is capture the redirection URL programatically and follow it on:

WebClient.HttpRequest.ProtocolVersion = "HTTP/1.1" 
BeginPage("http://localhost/") 
WebClient.HttpRequest.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; InfoPath.1; .NET CLR 1.0.3705; ANTSLOAD)" 
WebClient.HttpRequest.Headers.Set("UA-CPU", "x86") 
WebClient.Get("http://localhost/") 
EndPage("http://localhost/") 
' End of page 1 contains 1 request(s) 

Me.LogToFile(WebClient.ViewState) 'returns null 
Me.LogToFile(WebClient.HttpResponse.Location) 'returns null 

Sleep(7531) 
BeginPage("http://localhost/") 
WebClient.HttpRequest.Pragma = "no-cache" 
WebClient.HttpRequest.ContentType = "application/x-www-form-urlencoded" 
WebClient.HttpRequest.AddPostData("__EVENTTARGET", "Login1%3A_ctl0%3A_ctl7", False) 
WebClient.HttpRequest.AddPostData("__EVENTARGUMENT", "", False) 
WebClient.HttpRequest.AddPostData("__VIEWSTATE", WebClient.ViewState, False) 
WebClient.HttpRequest.AddPostData("Login1%3A_ctl0%3A_ctl3", "USERLOGINNAME", False) 
WebClient.HttpRequest.AddPostData("Login1%3A_ctl0%3A_ctl5", "USERPASSWORD", False) 
WebClient.Post("http://localhost/") 
If WebClient.HttpResponse.Status=301 Or WebClient.HttpResponse.Status=302 Then
WebClient.Get("http://localhost/"+WebClient.HttpResponse.Location)
End If
WebClient.HttpRequest.ContentType = Nothing 
WebClient.Get("http://localhost/") 
EndPage("http://localhost/")

nikolaiblackie

Ok I have tried this, but why is it that after the first WebClient.Get("http://localhost/"), WebClient.ViewState still returns null? I know that the default page definately contains viewstate and this should be coming through. This is causing the login post to fail everytime.

Do I need to look at using a get viewstate function like in this post? http://www.red-gate.com/messageboard/vi ... =viewstate
i.e.
Private Function GetViewState(ByVal content As String) As String

nikolaiblackie

Well I managed to get my login script running, this was the final version that works for me.

The key part is ensuring post data is encoded i.e. WebClient.HttpRequest.AddPostData("__VIEWSTATE", viewState, True)

Private Function GetViewState(ByVal content As String) As String
        Try
            Dim i As Integer
            Dim iStart As Integer
            Dim iEnd As Integer

            Dim vstate As String = ""
            Dim contentToFind As String = "__VIEWSTATE"

            i = content.IndexOf(contentToFind) + contentToFind.Length + 1

            If i > 0 Then 'We have found viewstate in the page
                iStart = content.IndexOf(Chr(34), i + 1) + 1
                iEnd = content.IndexOf(Chr(34), iStart)
                vstate = content.Substring(iStart, iEnd - iStart)
            End If
            GetViewState = vstate
        Catch ex As Exception
            Me.ReportError("GetViewState: " + ex.Message)
        End Try
    End Function

    Protected Overrides Sub Run()
        ' Script created with Internet Explorer on 29/03/2006 8:58:03 a.m.

        ' Random pause of between and 1 and 2 seconds
        ' (Remove this line if you want all scripts to start at the same time)
        RandomSleep(1000, 2000)
        Dim viewState As String

        WebClient.HttpRequest.ProtocolVersion = "HTTP/1.1"
        BeginPage("http://localhost/")
        WebClient.HttpRequest.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; InfoPath.1; .NET CLR 1.0.3705)"
        WebClient.HttpRequest.Headers.Set("UA-CPU", "x86")
        WebClient.Get("http://localhost/")
        EndPage("http://localhost/")
        ' End of page 1 contains 4 request(s).

        Me.LogToFile("WebClient.ViewState 1st request")
        Me.LogToFile(WebClient.ViewState)
        Me.LogToFile("WebClient.HttpResponse.Location 1st request")
        Me.LogToFile(WebClient.HttpResponse.Location) 
        Me.LogToFile("GetViewState 1st request")
        viewState = GetViewState(WebClient.HttpResponse.Content)
        Me.LogToFile(viewState)

        Sleep(7156)
        BeginPage("http://localhost/")
        WebClient.HttpRequest.Pragma = "no-cache"
        WebClient.HttpRequest.ContentType = "application/x-www-form-urlencoded"
        WebClient.HttpRequest.AddPostData("__EVENTTARGET", "Login1%3A_ctl0%3A_ctl7", False)
        WebClient.HttpRequest.AddPostData("__EVENTARGUMENT", "", False)
        WebClient.HttpRequest.AddPostData("__VIEWSTATE", viewState, True)
        WebClient.HttpRequest.AddPostData("Login1%3A_ctl0%3A_ctl3", "******", False)
        WebClient.HttpRequest.AddPostData("Login1%3A_ctl0%3A_ctl5", "****", False)
        WebClient.Post("http://localhost/")
        If WebClient.HttpResponse.Status = 301 Or WebClient.HttpResponse.Status = 302 Then
            Try
                WebClient.Get("http://localhost/" + WebClient.HttpResponse.Location)
            Catch ex As Exception
                Me.ReportError(ex.Message)
            End Try
        End If
        WebClient.HttpRequest.ContentType = Nothing
        WebClient.Get("http://localhost/")
        EndPage("http://localhost/")
        ' End of page 2 contains 2 request(s).
    End Function