using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
using System.Net;
using System.IO;
using System.IO.Compression;
using System.Text.RegularExpressions;

namespace System.Net
{
    /// <summary>  
    /// 有关HTTP请求的辅助类  
    /// </summary>  
    public class RequestHepler
    {
        private static readonly string DefaultUserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";

        /// <summary>  
        /// 创建GET方式的HTTP请求  
        /// </summary>  
        /// <param name="url">请求的URL</param>  
        /// <param name="timeout">请求的超时时间(毫秒)</param>  
        /// <param name="userAgent">请求的客户端浏览器信息，可以为空</param>  
        /// <param name="cookies">随同HTTP请求发送的Cookie信息，如果不需要身份验证可以为空</param>  
        /// <returns>HttpWebResponse</returns>  
        public static HttpWebResponse CreateGetHttpResponse(string url, int? timeout = null, string userAgent = null, CookieCollection cookies = null)
        {
            if (string.IsNullOrEmpty(url))
            {
                throw new ArgumentNullException("url");
            }
            HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;

            request.Proxy = null;
            request.Method = "GET";
            request.ContentType = "application/x-www-form-urlencoded";
            request.Headers.Add("Accept-Language: zh-cn");
            //request.Headers.Add("Accept-Encoding: gzip, deflate");//压缩
            request.UserAgent = DefaultUserAgent;
            if (!string.IsNullOrEmpty(userAgent))
            {
                request.UserAgent = userAgent;
            }
            if (timeout.HasValue)
            {
                request.Timeout = timeout.Value;
            }
            if (cookies != null)
            {
                request.CookieContainer = new CookieContainer();
                request.CookieContainer.Add(cookies);
            }
            return request.GetResponse() as HttpWebResponse;
        }

        /// <summary>  
        /// 创建POST方式的HTTP请求  
        /// </summary>  
        /// <param name="url">请求的URL</param>  
        /// <param name="parameters">随同请求POST的参数名称及参数值字典</param>  
        /// <param name="timeout">请求的超时时间</param>  
        /// <param name="userAgent">请求的客户端浏览器信息，可以为空</param>  
        /// <param name="requestEncoding">发送HTTP请求时所用的编码</param>  
        /// <param name="cookies">随同HTTP请求发送的Cookie信息，如果不需要身份验证可以为空</param>  
        /// <param name="Expect100Continue">如果该属性为 true，请求报头将发送到服务器。如果服务器没有拒绝请求，它将发送 100-Continue 响应，指示可以传输数据。如果像前一个示例那样，服务器要求身份验证，它将发送 401 响应，而客户端不一定未传输数据。 </param>  
        /// <returns>HttpWebResponse</returns>  
        public static HttpWebResponse CreatePostHttpResponse(string url, IDictionary<string, string> parameters, Encoding requestEncoding, int? timeout = null, string userAgent = null, CookieCollection cookies = null, bool Expect100Continue = true)
        {
            if (string.IsNullOrEmpty(url))
            {
                throw new ArgumentNullException("url");
            }
            if (requestEncoding == null)
            {
                throw new ArgumentNullException("requestEncoding");
            }
            HttpWebRequest request = null;
            //如果是发送HTTPS请求  
            if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))
            {
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);//总是接受证书                
                ServicePointManager.Expect100Continue = Expect100Continue;
                request = WebRequest.Create(url) as HttpWebRequest;
                request.ProtocolVersion = HttpVersion.Version10;
            }
            else
            {
                request = WebRequest.Create(url) as HttpWebRequest;
            }
            request.Proxy = null;
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.Headers.Add("Accept-Language: zh-cn");
            //request.Headers.Add("Accept-Encoding: gzip, deflate");//压缩

            if (!string.IsNullOrEmpty(userAgent))
            {
                request.UserAgent = userAgent;
            }
            else
            {
                request.UserAgent = DefaultUserAgent;
            }

            if (timeout.HasValue)
            {
                request.Timeout = timeout.Value;
            }
            request.CookieContainer = new CookieContainer();
            if (cookies != null)
            {
                request.CookieContainer.Add(cookies);
            }
            //如果需要POST数据  
            if (!(parameters == null || parameters.Count == 0))
            {
                StringBuilder buffer = new StringBuilder();
                int i = 0;
                foreach (string key in parameters.Keys)
                {
                    if (i > 0)
                    {
                        buffer.AppendFormat("&{0}={1}", key.Replace("#", string.Empty), parameters[key]);
                    }
                    else
                    {
                        buffer.AppendFormat("{0}={1}", key.Replace("#", string.Empty), parameters[key]);
                    }
                    i++;
                }
                byte[] data = requestEncoding.GetBytes(buffer.ToString());
                using (Stream stream = request.GetRequestStream())
                {
                    stream.Write(data, 0, data.Length);
                }
            }
            return request.GetResponse() as HttpWebResponse;
        }

        /// <summary>  
        /// 创建POST方式的HTTP请求  
        /// </summary>  
        /// <param name="url">请求的URL</param> 
        /// <param name="timeout">请求的超时时间</param>  
        /// <param name="userAgent">请求的客户端浏览器信息，可以为空</param>  
        /// <param name="cookies">随同HTTP请求发送的Cookie信息，如果不需要身份验证可以为空</param>  
        /// <param name="Expect100Continue">如果该属性为 true，请求报头将发送到服务器。如果服务器没有拒绝请求，它将发送 100-Continue 响应，指示可以传输数据。如果像前一个示例那样，服务器要求身份验证，它将发送 401 响应，而客户端不一定未传输数据。 </param>  
        /// <returns>HttpWebRequest</returns>  
        public static HttpWebRequest CreatePostHttpResponse(string url, int? timeout = null, string userAgent = null, CookieCollection cookies = null, bool Expect100Continue = true)
        {
            System.GC.Collect();
            //设置最大连接数
            ServicePointManager.DefaultConnectionLimit = 1000;

            if (string.IsNullOrEmpty(url))
            {
                throw new ArgumentNullException("url");
            }
            //如果是发送HTTPS请求  
            if (url.StartsWith("https", StringComparison.OrdinalIgnoreCase))
            {
                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);//总是接受证书                
                ServicePointManager.Expect100Continue = Expect100Continue;
            }
            HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
            request.Proxy = null;
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.Headers.Add("Accept-Language: zh-cn");
            //request.Headers.Add("Accept-Encoding: gzip, deflate");//压缩

            if (!string.IsNullOrEmpty(userAgent))
            {
                request.UserAgent = userAgent;
            }
            else
            {
                request.UserAgent = DefaultUserAgent;
            }

            if (timeout.HasValue)
            {
                request.Timeout = timeout.Value;
            }
            request.CookieContainer = new CookieContainer();
            if (cookies != null)
            {
                request.CookieContainer.Add(cookies);
            }
            return request;
        }
        /// <summary>
        /// 接受所有证书
        /// </summary>
        private static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
        {
            return true; //总是接受  
        }
    }
}