【笔记】使用千千静听服务器下载歌词

最近想做一个音乐播放器，播放器需要显示歌词，这就需要到网上下载歌词。花了两个晚上搞了一个歌词下载类，通过歌名和歌手算出响应代码到千千静听服务器下载

具体流程如下：

1、通过歌名 Title 和 歌手 Artist ，计算出歌词下载列表地址

　　先把Title和Artist转换为十六进制，带入下面服务器地址

　　歌词Id获取地址：http://ttlrcct2.qianqian.com/dll/lyricsvr.dll?sh?Artist={0}&Title={1}&Flags=0"

　　然后连接到地址，得到一个Xml文件，可以得到歌词的下载Id

2、通过 Id 和 Title 和 Artist 算出相应的Code，具体看代码（参考自网上）

　　歌词下载服务器地址：http://ttlrcct2.qianqian.com/dll/lyricsvr.dll?dl?Id={0}&Code={1}

下面是代码

　　定义两个类：LyricsHelper（辅助获取歌词Id）LrcInfo（歌词下载相应信息）

        public class LyricsHelper
        {
            //歌词Id获取地址
            private static readonly string SearchPath = "http://ttlrcct2.qianqian.com/dll/lyricsvr.dll?sh?Artist={0}&Title={1}&Flags=0";

            //根据artist和title获取歌词信息
            public static LrcInfo[] GetLrcList(string artist, string title, string filepath)
            {
                string artistHex = GetHexString(artist, Encoding.Unicode);
                string titleHex = GetHexString(title, Encoding.Unicode);

                string resultUrl = string.Format(SearchPath, artistHex, titleHex);
                
                XmlDocument doc = new XmlDocument();
                try
                {
                    doc.Load(resultUrl);

                    XmlNodeList nodelist = doc.SelectNodes("/result/lrc");
                    List<LrcInfo> lrclist = new List<LrcInfo>();
                    foreach (XmlNode node in nodelist)
                    {
                        XmlElement element = (XmlElement)node;
                        string artistItem = element.GetAttribute("artist");
                        string titleItem = element.GetAttribute("title");
                        string idItem = element.GetAttribute("id");
                        lrclist.Add(new LrcInfo(idItem, titleItem, artistItem, filepath));
                    }
                    return lrclist.ToArray();
                }
                catch (XmlException)
                {
                    return null;
                }
            }
            
            //把字符串转换为十六进制
            public static string GetHexString(string str, Encoding encoding)
            {
                StringBuilder sb = new StringBuilder();
                byte[] bytes = encoding.GetBytes(str);
                foreach (byte b in bytes)
                {
                    sb.Append(b.ToString("X").PadLeft(2, '0'));
                }
                return sb.ToString();
            }
        }
        
        public class LrcInfo
        {
            //歌词下载地址
            private static readonly string DownloadPath = "http://ttlrcct2.qianqian.com/dll/lyricsvr.dll?dl?Id={0}&Code={1}";

            public string FilePath { get; set; }
            public string Id { get; set; }
            public string Artist { get; set; }
            public string Title { get; set; }
            public string LrcUri { get; set; }

            public LrcInfo(string id, string title, string artist, string filepath)
            {
                this.FilePath = filepath;
                this.Id = id.Trim();
                this.Title = title;
                this.Artist = artist;
                //算出歌词的下载地址
                this.LrcUri = string.Format(DownloadPath, Id, CreateQianQianCode());
            }
            public bool DownloadLrc()
            {
                string file = FilePath;
                string directory = Path.GetDirectoryName(file) + "\\Lrc\\";
                if (!Directory.Exists(directory))
                {
                    Directory.CreateDirectory(directory);
                }
                string filepath = directory + Path.GetFileNameWithoutExtension(file) + ".lrc";
                WebRequest request = WebRequest.Create(LrcUri);

                StringBuilder sb = new StringBuilder();
                try
                {
                    using (StreamReader sr = new StreamReader(request.GetResponse().GetResponseStream(), Encoding.UTF8))
                    {
                        using (StreamWriter sw = new StreamWriter(filepath, false, Encoding.UTF8))
                        {
                            sw.Write(sr.ReadToEnd());
                        }
                    }
                    return true;
                }
                catch (WebException)
                {

                }
                return false;
            }


            private string CreateQianQianCode()
            {
                int lrcId = Convert.ToInt32(Id);
                string qqHexStr = LyricsHelper.GetHexString(Artist + Title, Encoding.UTF8);
                int length = qqHexStr.Length / 2;
                int[] song = new int[length];
                for (int i = 0; i < length; i++)
                {
                    song[i] = int.Parse(qqHexStr.Substring(i * 2, 2), System.Globalization.NumberStyles.HexNumber);
                }
                int t1 = 0, t2 = 0, t3 = 0;
                t1 = (lrcId & 0x0000FF00) >> 8;
                if ((lrcId & 0x00FF0000) == 0)
                {
                    t3 = 0x000000FF & ~t1;
                }
                else
                {
                    t3 = 0x000000FF & ((lrcId & 0x00FF0000) >> 16);
                }

                t3 = t3 | ((0x000000FF & lrcId) << 8);
                t3 = t3 << 8;
                t3 = t3 | (0x000000FF & t1);
                t3 = t3 << 8;
                if ((lrcId & 0xFF000000) == 0)
                {
                    t3 = t3 | (0x000000FF & (~lrcId));
                }
                else
                {
                    t3 = t3 | (0x000000FF & (lrcId >> 24));
                }

                int j = length - 1;
                while (j >= 0)
                {
                    int c = song[j];
                    if (c >= 0x80) c = c - 0x100;

                    t1 = (int)((c + t2) & 0x00000000FFFFFFFF);
                    t2 = (int)((t2 << (j % 2 + 4)) & 0x00000000FFFFFFFF);
                    t2 = (int)((t1 + t2) & 0x00000000FFFFFFFF);
                    j -= 1;
                }
                j = 0;
                t1 = 0;
                while (j <= length - 1)
                {
                    int c = song[j];
                    if (c >= 128) c = c - 256;
                    int t4 = (int)((c + t1) & 0x00000000FFFFFFFF);
                    t1 = (int)((t1 << (j % 2 + 3)) & 0x00000000FFFFFFFF);
                    t1 = (int)((t1 + t4) & 0x00000000FFFFFFFF);
                    j += 1;
                }

                int t5 = (int)Conv(t2 ^ t3);
                t5 = (int)Conv(t5 + (t1 | lrcId));
                t5 = (int)Conv(t5 * (t1 | t3));
                t5 = (int)Conv(t5 * (t2 ^ lrcId));

                long t6 = (long)t5;
                if (t6 > 2147483648)
                    t5 = (int)(t6 - 4294967296);
                return t5.ToString();
            }
            private long Conv(int i)
            {
                long r = i % 4294967296;
                if (i >= 0 && r > 2147483648)
                    r = r - 4294967296;

                if (i < 0 && r < 2147483648)
                    r = r + 4294967296;
                return r;
            }

        }

　　好了，传几个参数试一下

        LrcInfo[] infos = LyricsHelper.GetLrcList("周杰伦", "不能说的秘密", @"C:\不能说的秘密.mp3");
        if (infos[0].DownloadLrc())
        {
            MessageBox.Show("下载成功");
        }