Novice questions RRS feed

  • Question

  • User-365041795 posted

    Sorry if these seem too easy, but I am new to HttpHandlers.

    The manual process
    1.  I login to a secure site.
    2.  The site redirects me to a URI similar to this " https://subDomain.Domain.com/SubDir/desktop.asp?abc=EditLayout&defe=ChangeDep&Divi=qwerty&returnURL=
    3.  I click a search link which changes the query string and content displayed
    4.  I enter a search term and, if found, the results are displayed in a multi tabbed box.  The tabs appear to be controlled by javascript and selecting them displays different data.
    5.  A thing that I cannot explain is that if I view the source, none of the data is on the page, yet it is visible

    Now, I have got as far as passing my credentials to the site and being able to retrieve the login page.  What I cant figure out is the following;
    1.  How do I know if my credentials were accepted?  The HTTPWebResponse status code returns OK, but the login page is returned and not the redirected one.
    2.  Once the original post is done, do my credentials remain valid or are they lost?
    3.  How do they hide the data.

    My code is as follows....

    ' The Class module
    Class Scrape

    Private UserName As String
    Private UserPwd As String
    Private ProxyServer As String
    Private ProxyPort As Integer
    Private Request As String

    Sub New(ByVal HttpUserName As String, ByVal HttpUserPwd As String, ByVal HttpProxyServer As String, ByVal HttpProxyPort As Integer, ByVal HttpRequest As String)
          UserName = HttpUserName
          UserPwd = HttpUserPwd
          ProxyServer = HttpProxyServer
          ProxyPort = HttpProxyPort
          Request = HttpRequest
    End Sub 'New

    Public Overridable Function CreateWebRequest(ByVal uri As String, ByVal collHeader As NameValueCollection, ByVal RequestMethod As String, ByVal NwCred As Boolean) As HttpWebRequest
          Dim webrequest As HttpWebRequest = CType(webrequest.Create(uri), HttpWebRequest)
          webrequest.KeepAlive =
          webrequest.Method = RequestMethod
          Dim iCount As Integer = collHeader.Count
          Dim key As String
          Dim keyvalue As String
          Dim i As Integer
          For i = 0 To iCount - 1
                key = collHeader.Keys(i)
                keyvalue = collHeader(i)
                webrequest.Headers.Add(key, keyvalue)
          Next i
          webrequest.ContentType = "text/html"
          If ProxyServer.Length > 0 Then
                webrequest.Proxy = New WebProxy(ProxyServer, ProxyPort)
          End If
          webrequest.AllowAutoRedirect = False
          If NwCred Then
                Dim wrCache As New CredentialCache
    New Uri(uri), "Basic", New NetworkCredential(UserName, UserPwd))
                webrequest.Credentials = wrCache
          End If
          Return webrequest
    End Function 'CreateWebRequest

    Public Overridable Function GetFinalResponse(ByVal ReUri As String, ByVal Cookie As String, ByVal RequestMethod As String, ByVal NwCred As Boolean) As String
          Dim collHeader As New NameValueCollection
          If Cookie.Length > 0 Then
                collHeader.Add("Cookie", Cookie)
          End If
          Dim webrequest As HttpWebRequest = CreateWebRequest(ReUri, collHeader, RequestMethod, NwCred)
          Dim webresponse As HttpWebResponse
          webresponse =
    CType(webrequest.GetResponse(), HttpWebResponse)
          Dim sc = webresponse.StatusCode
          Dim st = webresponse.ResponseUri
          Dim enc As Encoding = System.Text.Encoding.GetEncoding(1252)
          Dim loResponseStream As New StreamReader(webresponse.GetResponseStream(), enc)
          Dim Response As String = loResponseStream.ReadToEnd()
          Return Response
    End Function 'GetFinalResponse

    Private Sub BuildReqStream(ByRef webrequest As HttpWebRequest)
          Dim bytes As Byte() = Encoding.ASCII.GetBytes(Request)
          webrequest.ContentLength = bytes.Length
          Dim oStreamOut As Stream = webrequest.GetRequestStream()
          oStreamOut.Write(bytes, 0, bytes.Length)
    End Sub 'BuildReqStream

    End Class

    'The code from the calling form

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
          Dim resp As New Scrape("username", "password", "", 0, "Submit")
          txtData.Text = resp.GetFinalResponse(https://www.SubDomain.MainDomain.com/Directory/default.asp, "", "POST", False)
          resp = Nothing
    End Sub


    Friday, July 8, 2005 11:49 AM

All replies

  • User-365041795 posted

    I've managed to resolve two problems.  1. I was not pointing to the correct uri after login and 2. I didn't allow for cookie support.  I can now navigate around the site.

    I still need some advice though.  When I view the source of the search page, this is what I see..

      <Input name=btnSearch type=button onclick="
            str = '<SParam>';
            str += '<System>CC_01</System>';
            str += '<Name>' + txtFName.value + '</Name>';
             '...........a few more parameters like the one above
            str += '<Seed>0</Seed>';
            str += '</SParam>';
      value="Search=" ID="SrcButton">>">

    I think the line 'TData.loadXML(str) is calling a javascript function that passes an xml query string (str), so a new question is how do I get this to execute and see the results?

    I'd really appreciate some help on this if anyone can provide it as I am stumped here.

    Thanks in advance

    Monday, July 11, 2005 4:13 AM
  • User-182265138 posted
    Hi Terry,
    the javascript code you saw is a methos called  Remote Scripting.
    you can use XMLHTTP to send some kind of data to a page, using a client side method and get a reponse, and ofcource a server side method is called on the other side.
    there are several components that do this job for you and most of them are free.
    one of them is called Ajax, you can see 3 or 4 articles about it and how you can use it in
    also take a look at this article :
    and now i have one question !
    how do you manage cookies in your http request ?
    would you please explain ?
    Monday, July 11, 2005 6:49 AM
  • User-365041795 posted

    Hi Ariya,

    Thanks you for your response.  I shall look this up now.

    In answer to your question, using the code from my first post I added

    In the CreateWebRequest function
    webrequest.CookieContainer = New CookieContainer

    If Not Me.Cookies Is Nothing And Me.Cookies.Count > 0 Then

    In the GetFinalResponse function after the line.......
    "webresponse = CType(webrequest.GetResponse(), HttpWebResponse)"

    If webresponse.Cookies.Count > 0 Then
          If Me.Cookies Is Nothing Then
                Me.Cookies = webresponse.Cookies
                Dim newCookie As Cookie
                For Each newCookie In webresponse.Cookies
                      Dim b As Boolean = False
                      Dim currentCookie As Cookie
                      For Each currentCookie In Me.Cookies
                            If currentCookie.Name = newCookie.Name Then
                                  currentCookie.Value = newCookie.Value
                                  b =
                                  Exit For
                            End If
                            If Not b Then
                            End If
    nd If
    End If


    Monday, July 11, 2005 9:32 AM
  • User-365041795 posted

    Hi Ariya,

    I have looked into remote scripting and Ajax and now understand what's happening and why I can't see the content on the page :)

    From my original post, I mentioned that I was attempting to scrape the data from a remote site.  What I can't yet grasp, despite the reading, is how I use Ajax or XMLHTTP in this manner.

    When I scrape, I get to the search page and find this
      <Input name=btnSearch type=button onclick="
            str = '<SParam>';
            str += '<System>CC_01</System>';
            str += '<Name>' + txtFName.value + '</Name>';
            str += '<Seed>0</Seed>';
            str += '</SParam>';
      value="Search=" ID="SrcButton">>">

    I can reformat the string by doing this

     Dim sb As New StringBuilder
     sb.Append("<Name>A.N Other</Name>;")

    But how do I process the function "TData.loadXML(sb);" back to the server?

    Can this be done using Ajax/XMLHTTP?


    Tuesday, July 12, 2005 6:04 AM
  • User-365041795 posted
    This may be better off in the XML section so it's been moved to http://forums.asp.net/987342/ShowPost.aspx
    Thursday, July 14, 2005 8:38 AM