using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;

namespace SatecGlobal.Utility
{
    public class HtmlSourceHelper
    {
        /// <summary>
        /// 方法一：比較推薦
        /// 用HttpWebRequest取得網頁源碼
        
 
/// 對於帶BOM的網頁很有效，不管是什麽編碼都能正確識別
        /// </summary>
        /// <param name="url">網頁地址" </param>
        /// <returns>返回網頁源文件</returns>
        public static string GetHtmlSource2(string url)
        {
            //處理內容
            string html = "";
            HttpWebRequest request 
 
= (HttpWebRequest)WebRequest.Create(url);
            request.Accept = "*/*"; //接受任意文件
            request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.1.4322)"; // 模擬使用IE在瀏覽 http://www.52mvc.com
            request.AllowAutoRedirect = true;//是否允許302
            //request.CookieContainer = new CookieContainer();
 
//cookie容器，
            request.Referer = url; //當前頁面的引用
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream stream = response.GetResponseStream();
            StreamReader reader = new StreamReader(stream, Encoding.Default);
            html = reader.ReadToEnd();
            stream.Close();
            return html;
        }


        /// <summary>
        /// 方法二
        /// </summary>
        /// <param name="Url"></param>
        /// <returns></returns>
        public static string GetHttpData2(string Url)
        {
            string sException = null;
            string sRslt = null;
            WebResponse oWebRps = null;
            WebRequest oWebRqst = WebRequest.Create(Url);
            oWebRqst.Timeout = 50000;
            try
            {
                oWebRps = oWebRqst.GetResponse();
            }
            catch (WebException e)
            {
                sException = e.Message.ToString();
            }
            catch (Exception e)
            {
                sException = e.ToString();
            }
            finally
            {
                if (oWebRps != null)
                {
                    StreamReader oStreamRd = new StreamReader(oWebRps.GetResponseStream(), Encoding.GetEncoding("utf-8"));
                    sRslt = oStreamRd.ReadToEnd();
                    oStreamRd.Close();
                    oWebRps.Close();
                }
            }
            return sRslt;
        }


        /// <summary>
        /// 方法三：
        /// </summary>
        /// <param name="url">/要訪問的網站地址</param>
        /// <param name="charSets">目標網頁的編碼，如果傳入的是null或者"",那就自動分析網頁的編碼</param>
        /// <returns></returns>
        public static string getHtml(string url, params  string[] charSets)
        {
            try
            {
                string charSet = null;
                if (charSets.Length == 1)
                {
                    charSet = charSets[0];
                }
                WebClient myWebClient = new WebClient(); //創建WebClient實例myWebClient
                // 需要註意的：
                //有的網頁可能下不下來，有種種原因比如需要cookie,編碼問題等等
                //這是就要具體問題具體分析比如在頭部加入cookie
                // webclient.Headers.Add("Cookie", cookie);
                //這樣可能需要一些重載方法.根據需要寫就可以了
                //獲取或設置用於對向 Internet 資源的請求進行身份驗證的網絡憑據.
                myWebClient.Credentials = CredentialCache.DefaultCredentials;
                //如果服務器要驗證用戶名，密碼
                //NetworkCredential mycred = new NetworkCredential(struser, strpassword);
                //myWebClient.Credentials = mycred;
                //從資源下載數據並返回字節數組.(加@是因為網址中間有"/"符號)
                byte[] myDataBuffer = myWebClient.DownloadData(url);
                string strWebData = Encoding.Default.GetString(myDataBuffer);
                //獲取網頁字符編碼描述信息
                Match charSetMatch = Regex.Match(strWebData, "<meta([^<]*)charset=([^<]*)", RegexOptions.IgnoreCase | RegexOptions.Multiline);
                string webCharSet = charSetMatch.Groups[2].Value;
                if (charSet == null || charSet == "")
                    charSet = webCharSet;
                if (charSet != null && charSet != "" && Encoding.GetEncoding(charSet) != Encoding.Default)
                {
                    strWebData = Encoding.GetEncoding(charSet).GetString(myDataBuffer);
                }
                else
                {
                    strWebData = Encoding.GetEncoding("utf-8").GetString(myDataBuffer);
                }
                return strWebData;
            }
            catch (Exception e) { return ""; }
        }
    }
}

三種獲取源代碼的方式