.NET Tumblr Login HTTPWebRequests

'Written By Sixem
Imports System.Net
Imports System.Text
Imports System.IO
Public Class TumblrAPI
    Public Shared User_Agent As String = CStr("Mozilla/5.0 (Windows; U; Windows NT 6.1; ru; rv:1.9.2.3) Gecko/20100401 Firefox/4.0 (.NET CLR 3.5.30729)")
    Public Shared TumblrCookies As New CookieContainer
    Public Shared Function Login(ByVal Email_ As String, ByVal Pass_ As String)
        Dim Get_Key As String = Get_Data("https://www.tumblr.com/login")
        Dim Extracted_Key As String = CStr(GetBetween(Get_Key, "data-form-key=", ">")).Replace("""", Nothing)
        Dim PostData As String = String.Format("user%5Bemail%5D={0}&user%5Bpassword%5D={1}&tumblelog%5Bname%5D=&user%5Bage%5D=&recaptcha_public_key=&recaptcha_response_field=&context=home_signup&follow=&http_referer=http://www.tumblr.com&form_key={2}&seen_suggestion=0&used_suggestion=0", Email_, Pass_, Extracted_Key)
        Post("https://www.tumblr.com/login", PostData)
        Return Get_Data("https://www.tumblr.com/dashboard")
    End Function
    Public Shared Function Get_Data(ByVal Site_ As String)
        Dim request As HttpWebRequest = DirectCast(WebRequest.Create(Site_), HttpWebRequest)
        request.CookieContainer = TumblrCookies
        Dim response As HttpWebResponse = DirectCast(request.GetResponse(), HttpWebResponse)
        Dim reader As New StreamReader(response.GetResponseStream())
        Return CStr(reader.ReadToEnd)
    End Function
    Public Shared Function Post(ByVal Site_ As String, ByVal Post_ As String)
        Dim postData As String = Post_
        Dim tempCookies As New CookieContainer
        Dim _Encryption As New UTF8Encoding
        Dim byteData As Byte() = _Encryption.GetBytes(postData)
        Dim postReq As HttpWebRequest = DirectCast(WebRequest.Create(Site_), HttpWebRequest)
        postReq.Method = "POST"
        postReq.KeepAlive = True
        postReq.CookieContainer = tempCookies
        postReq.ContentType = "application/x-www-form-urlencoded"
        postReq.Referer = Site_
        postReq.UserAgent = User_Agent
        postReq.ContentLength = byteData.Length
        postReq.AllowAutoRedirect = True
        Dim postreqstream As Stream = postReq.GetRequestStream()
        postreqstream.Write(byteData, 0, byteData.Length)
        postreqstream.Close()
        Dim postresponse As HttpWebResponse
        postresponse = DirectCast(postReq.GetResponse(), HttpWebResponse)
        tempCookies.Add(postresponse.Cookies)
        TumblrCookies = tempCookies
        Dim postreqreader As New StreamReader(postresponse.GetResponseStream())
        Return CStr(postreqreader.ReadToEnd)
    End Function
    Public Shared Function GetBetween(ByRef strSource As String, ByRef strStart As String, ByRef strEnd As String, _
    Optional ByRef startPos As Integer = 0) As String
        Dim iPos As Integer, iEnd As Integer, lenStart As Integer = strStart.Length
        Dim strResult As String
        strResult = String.Empty
        iPos = strSource.IndexOf(strStart, startPos)
        iEnd = strSource.IndexOf(strEnd, iPos + lenStart)
        If iPos <> -1 AndAlso iEnd <> -1 Then
            strResult = strSource.Substring(iPos + lenStart, iEnd - (iPos + lenStart))
        End If
        Return strResult
    End Function
End Class