bilibili secret key download

main.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.Text.RegularExpressions;
using System.Net;
using System.IO;
using System.IO.Compression;

namespace console
{
    internal class Program
    {
        private const string UserAgent = "Mozilla / 5.0(Windows NT 6.1; WOW64; rv:40.0) Gecko/20100101 Firefox/40.1";

        private const string AppKey = "1d8b6e7d45233436"; // "84956560bc028eb7"; //"f3bb208b3d081dc8"; // 

        private const string BiliKey = "560c52ccd288fed045859ed18bffd973";
        // "94aba54af9065f71de72f5508f1cd42e"; //"1c15888dc316e05a15fdd0a02ed6584f"; //


        private static void Main(string[] args)
        {
            /*testSign();
            return;*/


            Console.WriteLine("Bilibili Stream URL generation test by gdkchan");
            Console.WriteLine("Enter a video URL to extract the Stream:");

            const string url = "http://www.bilibili.com/video/av8885415/"; // Console.ReadLine();

            Console.WriteLine(string.Empty);

            Console.WriteLine("Trying to download the webpage...");

            var html = HttpGetGZip(url);
            var cId = Regex.Match(html, "cid=([0-9]*)").Groups[1].Value;

            var Params = new List<string>();

            Params.Add("appkey=" + AppKey);
            Params.Add("cid=" + 16776021);
            Params.Add("otype=json");
            Params.Add("quality=3");
            Params.Add("type=mp4");
            Console.WriteLine("payload: " + string.Join("&", Params.ToArray()));

            var baseSign = string.Join("&", Params.ToArray()) + BiliKey;
            var signature = GetMd5(baseSign);
            Console.WriteLine("sign: " + signature);

            Params.Add("sign=" + signature);

            var jsonurl = "http://interface.bilibili.com/playurl?" + string.Join("&", Params.ToArray());

            Console.WriteLine("Trying to download JSON from \"" + jsonurl + "\"...");
            Console.WriteLine(string.Empty);

            var json = HttpGet(jsonurl);

            //Extract all URLs from the JSON
            var urLs = Regex.Matches(json, "https?://[^\"]*");

            if (urLs.Count > 0)
            {
                Console.ForegroundColor = ConsoleColor.White;
                Console.WriteLine("URLs:");
                Console.ResetColor();

                foreach (Match streamUrl in urLs)
                {
                    Console.WriteLine(streamUrl.Value);
                }
            }
            else
            {
                //If we couldn't extract URLs then something is broken, show the returned message
                Console.WriteLine("Can't extract, see JSON below:" + Environment.NewLine + json);
            }

            Console.WriteLine(string.Empty);
            Console.WriteLine("Press any key to exit");

            Console.ReadKey();
        }

        private static string GenSign(string contentId)
        {
            var Params = new List<string> {"cid=" + contentId, "from=miniplay", "player=1"};

            var baseSign = string.Join("&", Params.ToArray()) + BiliKey;
            var signature = GetMd5(baseSign);

            return signature;
        }

        #region "Hash Utils"

        private static string GetMd5(string input)
        {
            //Calculates the MD5 of a Input string
            using (var hash = MD5.Create())
            {
                //Compute the MD5 Hash of the String on a Byte Array
                var hashed = hash.ComputeHash(Encoding.ASCII.GetBytes(input));

                //Convert Byte Array to a Hex String and returns it
                var output = new StringBuilder();
                foreach (var hb in hashed) output.Append(hb.ToString("X2"));
                return output.ToString().ToLowerInvariant();
            }
        }

        #endregion

        #region "HTTP Utils"

        private static string HttpGetGZip(string url)
        {
            //This just downloads a Webpage using HTTP Get and the Firefox User Agent
            var request = WebRequest.Create(url);
            ((HttpWebRequest) request).UserAgent = UserAgent;

            //Note: The page is GZip compressed, so we need to decompress it first
            var response = request.GetResponse();
            using (var reader = new GZipStream(response.GetResponseStream(), CompressionMode.Decompress))
            {
                using (var output = new MemoryStream())
                {
                    var buffer = new byte[0x1000]; //4KiB Buffer
                    var length = 0;

                    while ((length = reader.Read(buffer, 0, buffer.Length)) > 0)
                    {
                        output.Write(buffer, 0, length);
                    }

                    return Encoding.UTF8.GetString(output.ToArray());
                }
            }
        }

        private static string HttpGet(string url)
        {
            //Same thing of the function above, but without the GZip compression
            var request = WebRequest.Create(url);
            ((HttpWebRequest) request).UserAgent = UserAgent;

            var response = request.GetResponse();
            var reader = new StreamReader(response.GetResponseStream());

            return reader.ReadToEnd();
        }

        #endregion
    }
}