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HttpWebRequest POST result is not the same as POST via ServerXMLHT

I am attempting to post to a url (https://FakeURL/logon.asp) using the
HttpWebRequest class. The response for a succesful post will contain
the html for the logon user's default page.

We've accomplished this in the past utilizing the ServerXMLHTTP object. When
I try an equivalent? post utilizing the HttpWebRequest class,
the response contains the html for logon.asp (the same page that was posted
to), which indicates to me that in some way my post didn't work.
No exceptions are thrown, it's just that the wrong page is returned.

The request is through a proxy server to the internet, via https. I've set
the headers the same way as with the successful call through
ServerXMLHTTP. I've tried it both with setting and not setting the
Credentials property of the request. In setting Credentials, I've tried
using a CredentialCache, or just a NetworkCredential

The code for both the ServerXMLHTTP, and the .Net page is below. Can anyone
tell me what I'm missing?

Thanks,
Dave Brown


'Dot Net Code
-------------------------------------------------------------------------------------------

Public Class WebForm1

Inherits System.Web.UI.Page

#Region " Web Form Designer Generated Code "

'This call is required by the Web Form Designer.
<System.Diagnostics.DebuggerStepThrough()> Private Sub
InitializeComponent()

End Sub

'NOTE: The following placeholder declaration is required by the Web Form
Designer.
'Do not delete or move it.
Private designerPlaceholderDeclaration As System.Object

Private Sub Page_Init(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeComponent()
End Sub

#End Region

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
Dim sUID As String = "xxxxx"
Dim sPassword As String = "xxxxx"
Dim strURL As String = "https://FakeURL/logon.asp"
Dim strRetval As String
strRetval = getPage(strURL, "Mode=&Username=" & sUID & "&Password="
& sPassword)
Response.Write(strRetval)
End Sub
Public Shared Function getPage(ByVal url As String, ByVal payload As
String) As String
Dim result As WebResponse
Dim proxyObject As New WebProxy("proxy.fake.fake.com:8080", False)
Try

Dim RequestStream As Stream
Dim ReceiveStream As Stream
Dim encode As Encoding
Dim sr As StreamReader

'Convert the web request to an HttpWebRequest so the UserAgent
can be set
'Don't know if it makes a difference, but the xmlServerHttp
object did this
'so might as well try it here
Dim req As HttpWebRequest = CType(WebRequest.Create(url),
HttpWebRequest)

req.Method = "POST"
req.ContentType = "application/x-www-form-urlencoded"
req.UserAgent = "Mozilla/4.0 (compatible; MSIE 5.5; Windows NT
5.0)"
req.Proxy = proxyObject

'Tried this but it didn't seem to matter either way
'ensure that it sends default credentials
'req.PreAuthenticate = True

'Dim MyCredential As New System.Net.NetworkCredential("xxxxx",
"xxxxx")

'req.Credentials = MyCredential
'System.Net.CredentialCache.DefaultCredentials

'Dim cache As CredentialCache = New CredentialCache
'cache.Add(New Uri("https://FakeURL/logon.asp"), "Basic", New
NetworkCredential("xxxxx", "xxxxx"))
'req.Credentials = cache

' ----- This block is straight from the .Net samples
----------------------------------------------
Dim SomeBytes() As Byte
Dim UrlEncoded As New StringBuilder
Dim reserved() As Char = {ChrW(63), ChrW(61), ChrW(38)}

If payload <> Nothing Then
Dim i As Integer = 0
Dim j As Integer
While i < payload.Length
j = payload.IndexOfAny(reserved, i)
If j = -1 Then

UrlEncoded.Append(HttpUtility.UrlEncode(payload.Su bstring(i, payload.Length -
i)))
Exit While
End If

UrlEncoded.Append(HttpUtility.UrlEncode(payload.Su bstring(i, j - i)))
UrlEncoded.Append(payload.Substring(j, 1))
i = j + 1
End While
SomeBytes =
System.Text.Encoding.UTF8.GetBytes(UrlEncoded.ToSt ring())
req.ContentLength = SomeBytes.Length
RequestStream = req.GetRequestStream()
RequestStream.Write(SomeBytes, 0, SomeBytes.Length)
RequestStream.Close()
Else
req.ContentLength = 0
End If

'---------------------------------------------------------------------------------------------------

'Tried this as an alternative forumulation to the block directly
above
'Dim requestBytes() As Byte
'requestBytes = System.Text.Encoding.ASCII.GetBytes(payload)
'RequestStream = req.GetRequestStream()
'RequestStream.Write(requestBytes, 0, requestBytes.Length)

'---------------------------------------------------------------------------------------------------
result = req.GetResponse()
ReceiveStream = result.GetResponseStream()
encode = System.Text.Encoding.GetEncoding("utf-8")
sr = New StreamReader(ReceiveStream, encode)

Dim read(256) As Char
Dim count As Integer = sr.Read(read, 0, 256)

Dim strbRetval As New System.Text.StringBuilder
Do While count > 0
Dim str As String = New String(read, 0, count)
strbRetval.Append(str)
count = sr.Read(read, 0, 256)
Loop
Return strbRetval.ToString()
Catch Exc As Exception
Return Exc.Message
Finally
If Not result Is Nothing Then
result.Close()
End If
End Try
End Function
End Class
'-------------------------------------------------------------------------------------------------------------------

'ServerXMLHTTP Code
------------------------------------------------------------------------------------

Dim lResolve As Long
Dim lConnect As Long
Dim lSend As Long
Dim lReceive As Long
Dim xmlServerHTTP
xmlServerHTTP = CreateObject("MSXML2.ServerXMLHTTP.4.0")
lResolve = 60000
lConnect = 60000
lSend = 60000
lReceive = 120000

xmlServerHttp.setProxy(2, "proxy.fake.fake.com:8080", "")
xmlServerHttp.open("POST", "https://FakeURL/logon.asp", False)
xmlServerHttp.setRequestHeader("User-Agent", "Mozilla/4.0 (compatible; MSIE
5.5; Windows NT 5.0)")
xmlServerHttp.setRequestHeader("Content-Type",
"application/x-www-form-urlencoded")
xmlServerHttp.send("Mode=&Username=" & sUID & "&Password=" & sPassword)

While xmlServerHTTP.readyState <> 4
xmlServerHTTP.waitForResponse 1000
Wend
'----------------------------------------------------------------------------------------------------------
--
Dave Brown
Nov 19 '05 #1
1 2218
Dave Brown wrote:
I am attempting to post to a url (https://FakeURL/logon.asp) using
the HttpWebRequest class. The response for a succesful post will
contain the html for the logon user's default page.

We've accomplished this in the past utilizing the ServerXMLHTTP
object. When I try an equivalent? post utilizing the HttpWebRequest
class, the response contains the html for logon.asp (the same page
that was posted to), which indicates to me that in some way my post
didn't work. No exceptions are thrown, it's just that the wrong page
is returned.

The request is through a proxy server to the internet, via https.
I've set the headers the same way as with the successful call through
ServerXMLHTTP. I've tried it both with setting and not setting the
Credentials property of the request. In setting Credentials, I've
tried using a CredentialCache, or just a NetworkCredential

The code for both the ServerXMLHTTP, and the .Net page is below. Can
anyone tell me what I'm missing?


If you're posting to a logon page, and the server issues a session
cookie, your code will lose it. Create a CookieContainer instance and
set the HttpWebRequest.CookieContainer to this instance for all
requests you send.

Cheers,
--
http://www.joergjooss.de
mailto:ne********@joergjooss.de
Nov 19 '05 #2

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