用正则表达式从网页里面提取视频地址

//用正则表达式从网页里面提取视频地址

//获得一个页面地址，拿到页面html，然后正则表达式去匹配视频地址

//详细的看注释吧。

　1///<summary>
/// 网页视频处理类
///</summary>
///<history>
/// 
///</history>
    public class WebVideo
    {
        ///<summary>
/// 优酷、酷6、土豆等视频页面地址
///</summary>
        private string _pageUrl;
        
        ///<summary>
/// 是否启用页面压缩
///</summary>
        private bool _isCompressed;

        ///<summary>
/// 网站
///</summary>
        private VideoSite _site;


        public WebVideo ()
        {
            // TODO: Complete member initialization
        }


        ///<summary>
/// 实例化WebVideo类
///</summary>
///<param name="pageUrl">视频页面地址</param>
///<param name="isCompressed">获取页面时是否启用压缩</param>
        public WebVideo ( string pageUrl, bool isCompressed )
        {
            // TODO: Complete member initialization
            this._pageUrl = pageUrl.Trim();
            this._isCompressed = isCompressed;
            this._site = this.GetSite(_pageUrl);
        }

        
        ///<summary>
/// 根据Url地址得到网页的html源码
/// (使用gzip，deflate压缩，延迟低)
///</summary>
///<param name="Url"></param>
///<returns></returns>
        public string GetWebContent ( string Url )
        {
            string strResult = "";
            try
            {
                Stream decompressedStream = null;
                //声明一个HttpWebRequest请求
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);
                request.Accept = "*/*";
                request.Headers.Set("Pragma", "no-cache");
                //设置连接超时时间
                request.Timeout = 9000;
                request.UserAgent = "TaoCaiSpider1.0  Kevin-Gu's spider";
                request.Headers.Add("Accept-Encoding", "gzip,deflate");

                HttpWebResponse response = (HttpWebResponse)request.GetResponse();

                string compressMode = response.ContentEncoding.ToLower();
                Console.WriteLine(compressMode);

                if (compressMode == "gzip")
                {
                    decompressedStream 
                        = new GZipStream(response.GetResponseStream(), CompressionMode.Decompress);
                }
                else if (compressMode == "deflate")
                {
                    decompressedStream
                       = new DeflateStream(response.GetResponseStream(), CompressionMode.Decompress);
                }
                else
                {
                    // 貌似只有优酷启用了页面压缩。。。
                    decompressedStream = response.GetResponseStream();
                }

                Encoding encode = Encoding.GetEncoding(response.CharacterSet);
                using (StreamReader streamReader = new StreamReader(decompressedStream, encode))
                {
                    strResult = streamReader.ReadToEnd();
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("error occored:" + ex.Message);
            }
            return strResult;
        }





        ///<summary>
/// 使用正则表达式匹配获取视频文件地址
///</summary>
///<param name="htmlContent"></param>
///<returns></returns>
        public string GetVideoFileUrl (string htmlContent)
        {
            string[] rgxArr =new string[]{ 
                @"http://player\.youku\.com/player\.php/sid/[\w]{13}/v\.swf", //优酷的文件地址正则
                @"http://player\.ku6\.com/refer/[\w]{16}/v\.swf",
                @"http://js\.tudouui\.com/bin/player_online/[\w]+\.swf"
            };

            Regex rgx;

            // 使用不同的正则表达式来匹配视频文件地址
            switch (_site)
            {
                case VideoSite.YouKu:
                    rgx = new Regex(rgxArr[0]);
                    if (rgx.IsMatch(htmlContent))
                    {
                        return rgx.Match(htmlContent).ToString();
                    }
                    break;
                case VideoSite.TuDou:
                    rgx = new Regex(rgxArr[2]);
                    if (rgx.IsMatch(htmlContent))
                    {
                        return rgx.Match(htmlContent).ToString();
                    }
                    break;
                case VideoSite.Ku6:
                    rgx = new Regex(rgxArr[1]);
                    if (rgx.IsMatch(htmlContent))
                    {
                        return rgx.Match(htmlContent).ToString();
                    }
                    break;
                default:
                    break;
            }
           
            return string.Empty;
        }


        ///<summary>
/// 获得视频网页中视频文件地址
///</summary>
///<returns></returns>
        public string GetVideoUrl ()
        {
            string videoUrl = string.Empty;
           if (_isCompressed)
           {
               string html = this.GetWebContent(_pageUrl);
               videoUrl = this.GetVideoFileUrl(html);
           }
           else
           {
               string html = this.GetHtmlWithoutCompress(_pageUrl);
               videoUrl = this.GetVideoFileUrl(html);
           }
           return videoUrl;
        }


     
    }//end class


    ///<summary>
/// 视频网站枚举
///</summary>
    public enum VideoSite
    { 
        YouKu=0,
        Ku6=1,
        TuDou=2,
    };