[Function] Adf.ly Decode by fudmario[vb.net]

   Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        TextBox1.Text = AdflyUrlDecode("http://adf.ly/1NfMkS")
       
    End Sub

' Return: https://itunes.apple.com/us/app/game-of-thrones-ascent/id799145075

' ***********************************************************************
' Author           : fudmario
' Created          : 09-15-2015
'
' Last Modified By : fudmario
' Last Modified On : 09-16-2015
' ***********************************************************************
' <copyright file="Adfly_Decode.vb" company="fudmarioDev">
'     Copyright (c) fudmarioDev. All rights reserved.
' </copyright>
' <summary></summary>
' ***********************************************************************
Imports System.IO
Imports System.Net
Imports System.Text
Module AdflyDecode
    ''' <summary>
    '''     Decodifica una Url de Adf.ly.
    ''' </summary>
    ''' <param name="url">URL a decodificar.</param>
    ''' <returns>Retorna la Url Decodificada.</returns>
    Public Function AdflyUrlDecode(url As String) As String
        Try
            Dim sb As New StringBuilder
            Dim data As String = GetSource(url:=url)
            Dim rt As String() = {"ysmm = '", "'"c}
            Dim a As Integer = data.IndexOf(rt(0), StringComparison.Ordinal) + rt(0).Length + 1
            Dim b As Integer = data.Substring(a).IndexOf(rt(1), StringComparison.Ordinal) + 1
            Dim s As String = Mid(data, a, b)
            For i = 0 To s.Length - 1 Step 2
                sb.Append(s(i))
            Next
            For k = s.Length - 1 To 0 Step -2
                sb.Append(s(k))
            Next
            Return Encoding.ASCII.GetString(Convert.FromBase64String(sb.ToString())).Substring(2)
        Catch ex As Exception
            Return String.Empty
        End Try
    End Function

    ''' <summary>
    '''     Obtiene el Código Fuente de una Url.
    ''' </summary>
    ''' <param name="url">Url.</param>
    ''' <returns>Retorna el código fuente de una Url.</returns>
    Private Function GetSource(url As String) As String
        Try
            Return New StreamReader(WebRequest.Create(url).GetResponse().GetResponseStream()).ReadToEnd()
        Catch ex As Exception
            Return String.Empty
        End Try
    End Function
End Module

For i = 0 To s.Length - 1 Step 2
  sb.Append(s(i))
 Next
For k = s.Length - 1 To 0 Step -2
  sb.Append(s(k))
Next

Return Encoding.ASCII.GetString(Convert.FromBase64String(sb.ToString())).Substring(2)

<?php

function request( $url ) {
    $ua = 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1712.4 Safari/537.36';
    if ( !preg_match( '/^[a-zA-Z0-9\/]+$/', $url ) )
        return false;

    $ch = curl_init();
    curl_setopt_array( $ch, array(
        CURLOPT_FAILONERROR => true,
        CURLOPT_FOLLOWLOCATION => false,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT => 10,
        CURLOPT_USERAGENT => $ua,
        CURLOPT_URL => 'http://adf.ly/' . $url
    ) );
    $data = curl_exec( $ch );
    curl_close( $ch );

    if ( preg_match( "#var ysmm = '([a-zA-Z0-9+/=]+)'#", $data, $matches ) ) {
        $final = $url = decode( $matches[1] );
        // check for redirects
        $ch = curl_init();
        curl_setopt_array( $ch, array(
            CURLOPT_FAILONERROR => true,
            CURLOPT_FOLLOWLOCATION => true,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_HEADER => true,
            CURLOPT_NOBODY => true,
            CURLOPT_TIMEOUT => 10,
            CURLOPT_USERAGENT => $ua,
            CURLOPT_URL => $url
        ) );
        $data = curl_exec( $ch );
        if ( preg_match_all( '/Location:\s*(.+)\s*$/im', $data, $matches, PREG_SET_ORDER ) ) {
            $last = array_pop( $matches );
            $final = trim( $last[1] );
        }

        return array( $url, $final );
    }

    return false;
}

function decode( $ysmm ) {
    $left = '';
    $right = '';
    for ( $i = 0; $i < strlen( $ysmm ); $i++ ) {
        if ( $i % 2 == 0 ) {
            $left .= $ysmm[$i];
        } else {
            $right = $ysmm[$i] . $right;
        }
    }
    return substr( base64_decode( $left . $right ), 2 );
}

if ( isset( $_GET['url'] ) && $_GET['url'] ) {
    // strip out beginning (everything up to last slash)
    $stripped = '';
    $slashes = explode( '/', $_GET['url'] );
    $stripped = array_pop( $slashes );

    list( $url, $final ) = request( $stripped );
    if ( $url ) {
        echo '<p>Your URL is <a href="' . $url . '">' . $url . '</a>';
        if ( $url != $final ) {
            echo ' (<a href="' . $final . '">' . $final . '</a>)';
        }
        echo '</p>';
    } else {
        // try 2 parts
        $stripped = array_pop( $slashes ) . '/' . $stripped;
        list( $url, $final ) = request( $stripped );
        if ( $url ) {
            echo '<p>Your URL is <a href="' . $url . '">' . $url . '</a>';
            if ( $url != $final ) {
                echo ' (<a href="' . $final . '">' . $final . '</a>)';
            }
            echo '</p>';
        } else {
            echo '<p>Adf.ly URL not found</p>';
        }
    }
}
?>