HttpWebRequest Login data Then Redirect

问题:

I'm trying to use HttpwebRequest and Httpwebresponse to log into a website via POST then once authenticated have it redirect to a default page within the new site. I'm able to do a responsereader.ReadttoEnd() put am unsure of how to get an automatic redirect.

     Dim ccContainer As New CookieContainer()
            Dim encoding As New ASCIIEncoding()
            Dim strId As String = "username"
            Dim strName As String = "password"

 Dim postData As String = "UAPMURL=&UAPMURLxx=xx&login=" & strId
        postData += ("&password1=" & strName)
        Dim data As Byte() = encoding.GetBytes(postData)

        ' Prepare web request...
        Dim myRequest As HttpWebRequest = DirectCast(WebRequest.Create("http://www.LOGINURLHERE.COM/LOGIN.PHP?"), HttpWebRequest)

        Dim cc As New CookieContainer


        ' <<--- This is the key word of the day
        myRequest.Method = "POST"
        myRequest.AllowAutoRedirect = False
        myRequest.ContentType = "application/x-www-form-urlencoded"
        myRequest.UserAgent = "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)"
        myRequest.KeepAlive = True
        myRequest.CookieContainer = New CookieContainer()

        myRequest.ContentLength = data.Length
        Dim newStream As Stream = myRequest.GetRequestStream()
        ' Send the data.
        newStream.Write(data, 0, data.Length)
        newStream.Close()

        Dim _response As HttpWebResponse = DirectCast(myRequest.GetResponse(), HttpWebResponse)
        If myRequest.HaveResponse Then
            For Each retCookie As Cookie In _response.Cookies
                cc.Add(retCookie)
            Next
        End If

        Dim request As HttpWebRequest = DirectCast(WebRequest.Create("http://www.DESTINATIONURL.COM/Main.php"), HttpWebRequest)
        request.CookieContainer = cc
        request.AllowAutoRedirect = False


        Dim _res As HttpWebResponse = DirectCast(request.GetResponse(), HttpWebResponse)

---

If I do this ...

Comment out this line

 'Dim _res As HttpWebResponse = DirectCast(request.GetResponse(), HttpWebResponse)

Use these...it reads and fill my current page with the data from the destination URL. Am I missing something to get it to auto redirect? Thanks

   Dim request As HttpWebRequest = DirectCast(WebRequest.Create("http://www.destinationurl.com"), HttpWebRequest)
    request.CookieContainer = cc
    request.AllowAutoRedirect = False

 Dim responseReader As New StreamReader(request.GetResponse().GetResponseStream())
    Dim responseData As String = responseReader.ReadToEnd()
    responseReader.Close()
    Response.Write(responseData)

回答1:

You don't redirect; The server redirects.

• If the server sends you a redirect response (code=3xx), you request the URL it redirects you to.
• If the redirect is handled transparently, the _response.ResponseURI will contain the address it redirected to. If not, you have to read the redirect header and decide yourself whether or not to request the new page.
• If the server doesn't redirect at all, you just need to request whatever URL you want once you have your authentication cookie.