Codenstuff.com

#Region "Generate You-Tube URL"
    Public Sub MakeDownloadURL(ByVal url As String, ByRef output As String, Optional ByRef type As String = "", Optional ByRef size As Integer = 0)
        'PERFORMS CLEANUP
        downloadurl = ""
        If request IsNot Nothing Then
            Try
                request.Abort()
            Catch
            End Try
        End If
        If response IsNot Nothing Then
            Try
                response.Close()
            Catch
            End Try
        End If
        Try
            source = ""
        Catch
        End Try

        request = DirectCast(HttpWebRequest.Create(url.ToString), HttpWebRequest)
        Try
            response = DirectCast(request.GetResponse, HttpWebResponse)
        Catch
            type = ""
            Exit Sub
        End Try
        source = New StreamReader(response.GetResponseStream, System.Text.Encoding.Default).ReadToEnd

        If source.IndexOf("video_id") > -1 Then
            'This grabs the .flv location URL ready for doownloading.
            Dim signature As String = source
            If signature.Contains("&fmt_url_map=") = True Then
                Try
                    signature = System.Text.RegularExpressions.Regex.Split(signature, "&fmt_url_map=")(1)
                Catch
                End Try
            ElseIf signature.Contains(Chr(34) + "fmt_url_map" + Chr(34) + ": " + Chr(34)) = True Then
                Try
                    signature = System.Text.RegularExpressions.Regex.Split(signature, Chr(34) + "fmt_url_map" + Chr(34) + ": " + Chr(34))(1)
                Catch
                End Try
            Else
                Debug.WriteLine("Critical Error: Download URL could not be produced.")
                type = ""
                Exit Sub
            End If

            'This changes the URL to conform to internet standards eg. %20 = " "
            signature = signature.Remove(0, 5)
            signature = signature.Replace("%252C", ",")
            signature = signature.Replace("%2F", "/")
            signature = signature.Replace("%3D", "=")
            signature = signature.Replace("%3F", "?")
            signature = signature.Replace("%3A", ":")
            signature = signature.Replace("%26", "&")
            Dim sig2 As String = signature
            sig2 = sig2.IndexOf("http", 30)
            signature = signature.Remove(sig2, signature.Length - sig2)
            signature = signature.Remove(signature.IndexOf("%"), 7)
            'Removes any remaining % characters from the string.
            signature = signature.Replace("%", "")

            'Checks for and fixes any malformed http requests in the string.
            If signature.StartsWith("ttp://") Then
                signature = signature.Replace("ttp://", "http://")
            End If

            'Checks for and Removes any remaining C characters from the string.
            If signature.Chars(signature.Length - 1) = "C" Then
                signature = signature.Remove(signature.Length - 1, 1)
            End If

            'Checks for videos such as http://www.youtube.com/watch?v=LvLCvdeWcsw that would not download due to a new layout of download data.
            If signature.Contains("rv.2.rating") Then
                Dim n As Integer = signature.IndexOf(ChrW(34) + ",")
                signature = signature.Remove(n, signature.Length - n)
            End If

            'PERFORMS CLEANUP
            If request2 IsNot Nothing Then
                Try
                    request2.Abort()
                Catch
                End Try
            End If
            If response2 IsNot Nothing Then
                Try
                    response2.Close()
                Catch
                End Try
            End If

            Try
                request2 = DirectCast(HttpWebRequest.Create(signature), HttpWebRequest)
            Catch
                type = ""
                Exit Sub
            End Try
            response2 = DirectCast(request2.GetResponse, HttpWebResponse)
            If response2.ContentType = "video/x-flv" Then
                type = ".flv"
                output = signature
                size = response2.ContentLength
            ElseIf response2.ContentType = "video/mp4" Then
                type = ".mp4"
                output = signature
                size = response2.ContentLength
            Else
                type = ""
                output = ""
                Exit Sub
            End If
        End If
    End Sub
#End Region