Imports System
Imports System.Data
Imports System.Configuration
Imports System.Web
Imports System.Net
Imports System.IO
Imports System.Collections.Specialized
Public Class OAuth_Twitter


    Dim Oauth As New OAuth.OAuthBase

    Public consumerKey As String = "CgZiTeNqGk2c0eZSdb9qg"
    Public consumerSecret As String = "Sf7DGMTiK4cyU8qOuqOWX4yCNCwAdcRAlAj02cOA"
    Public token As String = ""
    Public tokenSecret As String = ""
    Public Const REQUEST_TOKEN As String = "http://twitter.com/oauth/request_token"
    Public Const AUTHORISE As String = "http://twitter.com/oauth/authorize"
    Public Const ACCESS_TOKEN As String = "http://twitter.com/oauth/access_token"
    Public Function AuthorizationLinkGet()
        Dim ret As String = Nothing

        Dim response As String = OAuthWebRequest("GET", REQUEST_TOKEN, String.Empty)

        If (response.Length > 0) Then
            REM response contains token and token secret.  We only need the token.
            Dim qs As NameValueCollection = HttpUtility.ParseQueryString(response)
            If (Not qs.Item("oauth_token") = Nothing) Then
                ret = AUTHORISE & "?oauth_token=" & qs.Item("oauth_token")
            End If
        End If
        Return ret
    End Function

    Public Sub AccessTokenGet(ByVal authToken As String)

        Dim response As String = oAuthWebRequest("POST", ACCESS_TOKEN, String.Empty)

        If (response.Length > 0) Then

            REM    //Store the Token and Token Secret
            Dim qs As NameValueCollection = HttpUtility.ParseQueryString(response)
            If (Not qs.Item("oauth_token") = Nothing) Then
                Token = qs.Item("oauth_token")
            End If
            If (Not qs.Item("auth_token_secret") = Nothing) Then
                TokenSecret = qs.Item("oauth_token_secret")
            End If
        End If
    End Sub
    Public Function oAuthWebRequest(ByVal Method As String, ByVal url As String, ByVal postData As String)

        Dim outUrl As String = ""
        Dim querystring As String = ""
        Dim ret As String = ""


        REM            //Setup postData for signing.
        REM         //Add the postData to the querystring.
        If (Method = "POST") Then

            If (postData.Length > 0) Then

                REM              //Decode the parameters and re-encode using the oAuth UrlEncode method.
                Dim qs As NameValueCollection = HttpUtility.ParseQueryString(postData)
                postData = ""
                For Each key As String In qs.AllKeys

                    If (postData.Length > 0) Then
                        postData &= "&"
                    End If
                    qs.Item(key) = HttpUtility.UrlDecode(qs.Item(key))
                    qs.Item(key) = HttpUtility.UrlEncode(qs.Item(key))
                    postData &= key + "=" & qs.Item(key)
                next
            End If
            If (url.IndexOf("?") > 0) Then
                url &= "&"
            Else
                url &= "?"
            End If
            url &= postData
        End If
        Dim URI As New Uri(url)

        Dim nonce As String = Oauth.GenerateNonce()
        Dim timeStamp As String = Oauth.GenerateTimeStamp()

        REM            //Generate Signature
        Dim sig As String = Oauth.GenerateSignature(URI, _
            consumerKey, _
            consumerSecret, _
            token, _
            tokenSecret, _
            Method, _
            timeStamp, _
            nonce, _
            outUrl, _
            querystring)

        querystring &= "&oauth_signature=" & HttpUtility.UrlEncode(sig)

        REM     //Convert the querystring to postData
        If (Method = "POST") Then
            postData = querystring
            querystring = ""
        End If

        If (querystring.Length > 0) Then
            outUrl &= "?"
        End If

        ret = WebRequest(Method, outUrl & querystring, postData)

        Return ret
    End Function
    Public Function WebRequest(ByVal Method As String, ByVal url As String, ByVal postData As String)

        Dim web_Request As HttpWebRequest = Nothing
        Dim requestWriter As StreamWriter = Nothing
        Dim responseData As String = Nothing

        web_Request = System.Net.WebRequest.Create(url)
        web_Request.Method = Method.ToString()
        web_Request.ServicePoint.Expect100Continue = False
        REM            //webRequest.UserAgent  = "Identify your application please.";
        REM         //webRequest.Timeout = 20000;

        If (Method = "POST") Then

            web_Request.ContentType = "application/x-www-form-urlencoded"

            REM //POST the data.
            requestWriter = New StreamWriter(web_Request.GetRequestStream())
            Try

                requestWriter.Write(postData)

            Catch

                Throw

            Finally

                requestWriter.Close()
                requestWriter = Nothing
            End Try
            end if

        responseData = WebResponseGet(web_Request)

        WebRequest = Nothing

        Return responseData

    End Function
    Public Function WebResponseGet(ByVal web_Request As HttpWebRequest)


        Dim responseReader As StreamReader = Nothing
        Dim responseData As String = ""

        Try

            responseReader = New StreamReader(web_Request.GetResponse.GetResponseStream())
            responseData = responseReader.ReadToEnd()

        Catch

            Throw

        Finally

            web_Request.GetResponse().GetResponseStream().Close()
            responseReader.Close()
            responseReader = Nothing

        End Try

        Return responseData
    End Function
End Class