using System.Text;
using System.Net;
using System.IO;
using System.Text.RegularExpressions;
using System.Security.Cryptography.X509Certificates;
using System.Net.Security;

namespace WebRequestTest
{
    /// <summary>
    /// 動態類，每個實例使用單獨session
    /// </summary>
    public class HttpHelperNew
    {
       public CookieContainer cookie = new CookieContainer();
        /// <summary>
        /// post請求返回html
        /// </summary>
        /// <param name="Url"></param>
        /// <param name="postDataStr"></param>
        /// <returns></returns>
        public string HttpPost(string Url, string postDataStr)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);
            //request.AllowAutoRedirect = false; //禁止自動重定向
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = Encoding.UTF8.GetByteCount(postDataStr);
            request.CookieContainer = cookie; //cookie信息由CookieContainer自行維護
            Stream myRequestStream = request.GetRequestStream();
            StreamWriter myStreamWriter = new StreamWriter(myRequestStream, Encoding.GetEncoding("gb2312"));
            myStreamWriter.Write(postDataStr);
            myStreamWriter.Close();

            HttpWebResponse response = null;
            try
            {
                this.SetCertificatePolicy();
                response = (HttpWebResponse)request.GetResponse();
            }
            catch (System.Exception ex)
            {
            }
            //獲取重定向地址
            //string url1 = response.Headers["Location"];
            if (response !=null)
            {
                Stream myResponseStream = response.GetResponseStream();
                StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
                string retString = myStreamReader.ReadToEnd();
                myStreamReader.Close();
                myResponseStream.Close();
                return retString;
            }
            else
            {
                return "error"; //post請求返回為空
            }
        }

        /// <summary>
        /// get請求獲取返回的html
        /// </summary>
        /// <param name="Url"></param>
        /// <param name="postDataStr"></param>
        /// <returns></returns>
        public string HttpGet(string Url, string Querydata)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url + (Querydata == "" ? "" : "?") + Querydata);
            request.Method = "GET";
            request.ContentType = "text/html;charset=UTF-8";
            request.CookieContainer = cookie;
            this.SetCertificatePolicy();
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
           // response.Cookies = cookie.GetCookies(response.ResponseUri);
            Stream myResponseStream = response.GetResponseStream();
            StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
            string retString = myStreamReader.ReadToEnd();
            myStreamReader.Close();
            myResponseStream.Close();
            return retString;
        }

        /// <summary>
        /// 獲得響應中的圖像
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        public Stream GetResponseImage(string url)
        {
            Stream resst = null;
            try
            {
                HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
                req.KeepAlive = true;
                req.Method = "GET";
                req.AllowAutoRedirect = true;
                req.CookieContainer = cookie;
                req.ContentType = "application/x-www-form-urlencoded";
                req.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
                req.Timeout = 50000;

                Encoding myEncoding = Encoding.GetEncoding("UTF-8");
                this.SetCertificatePolicy();
                HttpWebResponse res = (HttpWebResponse)req.GetResponse();
                resst = res.GetResponseStream();

                return resst;
            }
            catch
            {
                return null;
            }
        }

        /// <summary>
        /// 正則獲取匹配的第一個值
        /// </summary>
        /// <param name="html"></param>
        /// <param name="pattern"></param>
        /// <returns></returns>
        public string getStringByRegex(string html,string pattern)
        {

            Regex re = new Regex(pattern, RegexOptions.IgnoreCase);
            MatchCollection matchs = re.Matches(html);
            if (matchs.Count > 0)
            {
                return matchs[0].Groups[1].Value;
            }
            else
                return "";
        }

        /// <summary>
        /// 正則驗證返回的response是否正確
        /// </summary>
        /// <param name="html"></param>
        /// <param name="pattern"></param>
        /// <returns></returns>
        public bool verifyResponseHtml(string html ,string pattern)
        {
            Regex re = new Regex(pattern);
            return re.IsMatch(html);
        }

        //注冊證書驗證回調事件，在請求之前注冊
        private void SetCertificatePolicy()
        {
            ServicePointManager.ServerCertificateValidationCallback
                       += RemoteCertificateValidate;
        }
        /// <summary> 
        /// 遠程證書驗證，固定返回true
        /// </summary> 
        private static bool RemoteCertificateValidate(object sender, X509Certificate cert,
            X509Chain chain, SslPolicyErrors error)
        {
            return true;
        } 
    }
}