[C#]基于HttpWebRequest和HttpWebResponse的HttpHelper

C#中实现POST的方法很多，常用的是WebBrowser、WebClient、HttpWebRequest和HttpWebResponse。

1、WebBrowser基本是在DocumentCompleted中分析HtmlDocument ；

2、WebClient是对HttpWebRequest和HttpWebResponse的封装，用起来更方便，但是灵活性还是不及HttpWebRequest和HttpWebResponse；

3、HttpWebRequest和HttpWebResponse更底层，灵活度更好，不过代码更多，我做了一个简单的封装，将GET改成分段读取，并加入代理、进度条和错误重试处理。代码如下：

 

using System;
using System.IO;
using System.Net;
using System.Text;

namespace Van.Base
{
     public  class HttpHelper
    {
         #region 委托 事件
         public  delegate  void dgtProgValueChanged( long Value);
         ///   <summary>
         ///  进度改变事件
         ///   </summary>
         public  event dgtProgValueChanged OnProgValueChanged;
         #endregion

         #region 属性
         ///   <summary>
         ///  代理
         ///   </summary>
         public WebProxy Proxy {  get;  set; }
         ///   <summary>
         ///  Cookie
         ///   </summary>
         public CookieContainer UserCookie {  get;  set; }
         ///   <summary>
         ///  重试次数
         ///   </summary>
         public  int IAfreshTime {  get;  set; }
         ///   <summary>
         ///  错误次数
         ///   </summary>
         public  int IErrorTime {  get;  private  set; }

         long m_ProgValue =  0;
         ///   <summary>
         ///  当前读取字节
         ///   </summary>
         public  long ProgValue
        {
             get {  return m_ProgValue; }
             private  set
            {
                m_ProgValue = value;
                 if (OnProgValueChanged !=  null)
                {
                    OnProgValueChanged(value);
                }
            }
        }
         ///   <summary>
         ///  待读取最大字节
         ///   </summary>
         public  long ProgMaximum {  get;  private  set; }

         #endregion

         #region 方法
         #region Get
         ///   <summary>
         ///  获取HTML
         ///   </summary>
         ///   <param name="URL"> 地址 </param>
         ///   <param name="Accept"> Accept请求头 </param>
         ///   <returns> Html代码 </returns>
         public  string GetHTML( string URL,  string Accept)
        {
             return GetHTML(URL, Accept, System.Text.Encoding.UTF8);
        }
         ///   <summary>
         ///  获取HTML
         ///   </summary>
         ///   <param name="URL"> 地址 </param>
         ///   <param name="Accept"> Accept请求头 </param>
         ///   <param name="encoding"> 字符编码 </param>
         ///   <returns> Html代码 </returns>
         public  string GetHTML( string URL,  string Accept, Encoding encoding)
        {
             return GetHTML(URL, Accept, encoding,  1024);
        }
         ///   <summary>
         ///  获取HTML
         ///   </summary>
         ///   <param name="URL"> 地址 </param>
         ///   <param name="Accept"> Accept请求头 </param>
         ///   <param name="encoding"> 字符编码 </param>
         ///   <param name="bufflen"> 数据包大小 </param>
         ///   <returns> Html代码 </returns>
         public  string GetHTML( string URL,  string Accept, Encoding encoding,  int bufflen)
        {
            IErrorTime =  0;
             return _GetHTML(URL, Accept, encoding, bufflen);
        }
         ///   <summary>
         ///  获取HTML
         ///   </summary>
         ///   <param name="URL"> 地址 </param>
         ///   <param name="Accept"> Accept请求头 </param>
         ///   <param name="encoding"> 字符编码 </param>
         ///   <param name="bufflen"> 数据包大小 </param>
         ///   <returns> Html代码 </returns>
         private  string _GetHTML( string URL,  string Accept, Encoding encoding, int bufflen)
        {
             try
            {
                HttpWebRequest MyRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
                MyRequest.Proxy = Proxy;
                MyRequest.Accept = Accept;
                 if (UserCookie ==  null)
                {
                    UserCookie =  new CookieContainer();
                }
                MyRequest.CookieContainer = UserCookie;
                HttpWebResponse MyResponse = (HttpWebResponse)MyRequest.GetResponse();
                 return _GetHTML(MyResponse, encoding, bufflen);
            }
             catch (Exception erro)
            {
                 if (erro.Message.Contains( " 连接 ") && IAfreshTime - IErrorTime >  0)
                {
                    IErrorTime++;
                     return _GetHTML(URL, Accept, encoding, bufflen);
                }
                 throw;
            }
        }
         ///   <summary>
         ///  获取HTML
         ///   </summary>
         ///   <param name="MyResponse"></param>
         ///   <param name="encoding"> 字符编码 </param>
         ///   <param name="bufflen"> 数据包大小 </param>
         ///   <returns></returns>
         private  string _GetHTML(HttpWebResponse MyResponse, Encoding encoding,  int bufflen)
        {
             using (Stream MyStream = MyResponse.GetResponseStream())
            {

                    ProgMaximum = MyResponse.ContentLength;
                     string result =  null;
                     long totalDownloadedByte =  0;
                     byte[] by =  new  byte[bufflen];
                     int osize = MyStream.Read(by,  0, by.Length);
                     while (osize >  0)
                    {
                        totalDownloadedByte = osize + totalDownloadedByte;
                        result += encoding.GetString(by,  0, osize);
                        ProgValue = totalDownloadedByte;
                        osize = MyStream.Read(by,  0, by.Length);
                    }
                    MyStream.Close();
                     return result;
            }
        }
         #endregion


         #region GetImg

         public System.Drawing.Bitmap Getimg( string URL,  string Accept)
        {
             return _GetBit(URL, Accept);
        }
         ///   <summary>
         ///  获取HTML
         ///   </summary>
         ///   <param name="URL"> 地址 </param>
         ///   <param name="Accept"> Accept请求头 </param>
         ///   <returns> Html代码 </returns>
         private System.Drawing.Bitmap _GetBit( string URL,  string Accept)
        {
            HttpWebRequest MyRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
            MyRequest.Proxy = Proxy;
            MyRequest.Accept = Accept;
             if (UserCookie ==  null)
            {
                UserCookie =  new CookieContainer();
            }
            MyRequest.CookieContainer = UserCookie;
            HttpWebResponse MyResponse = (HttpWebResponse)MyRequest.GetResponse();
             return _GetBit(MyResponse);
        }

         ///   <summary>
         ///  获取图像
         ///   </summary>
         ///   <param name="MyResponse"></param>
         ///   <returns></returns>
         private System.Drawing.Bitmap _GetBit(HttpWebResponse MyResponse)
        {
             using (Stream MyStream = MyResponse.GetResponseStream())
            {
                 return  new System.Drawing.Bitmap(MyStream);
            }
        }
         #endregion

         #region Post
         ///   <summary>
         ///  回发(字符编码默认UTF-8)
         ///   </summary>
         ///   <param name="URL"> 回发地址 </param>
         ///   <param name="PostData"> 参数 </param>
         ///   <returns> Html代码 </returns>
         public  string PostPage( string URL,  string PostData)
        {
             return PostPage(URL, PostData, System.Text.Encoding.UTF8);
        }
         ///   <summary>
         ///  回发
         ///   </summary>
         ///   <param name="URL"> 回发地址 </param>
         ///   <param name="PostData"> 参数 </param>
         ///   <param name="encoding"> 字符编码 </param>
         ///   <returns> Html代码 </returns>
         public  string PostPage( string URL,  string PostData, Encoding encoding)
        {
             return PostPage(URL, PostData, encoding,  null);
        }
         ///   <summary>
         ///  回发
         ///   </summary>
         ///   <param name="URL"> 回发地址 </param>
         ///   <param name="PostData"> 参数 </param>
         ///   <param name="encoding"> 字符编码 </param>
         ///   <returns> Html代码 </returns>
         public  string PostPage( string URL,  string PostData, Encoding encoding,  string ContentType)
        {
            IErrorTime =  0;
             return _PostPage(URL, PostData, encoding, ContentType);
        }
         ///   <summary>
         ///  回发
         ///   </summary>
         ///   <param name="URL"> 回发地址 </param>
         ///   <param name="PostData"> 参数 </param>
         ///   <param name="encoding"> 字符编码 </param>
         ///   <returns> Html代码 </returns>
         private  string _PostPage( string URL,  string PostData, Encoding encoding, string ContentType)
        {
             try
            {
                 if (ContentType== null)
                {
                    ContentType =  " application/x-www-form-urlencoded ";
                }
                HttpWebRequest MyRequest = (HttpWebRequest)HttpWebRequest.Create(URL);
                MyRequest.Proxy = Proxy;
                 if (UserCookie ==  null)
                {
                    UserCookie =  new CookieContainer();
                }
                MyRequest.CookieContainer = UserCookie;
                MyRequest.Method =  " POST ";
                MyRequest.ContentType = ContentType;
                 byte[] b = encoding.GetBytes(PostData);
                MyRequest.ContentLength = b.Length;
                 using (System.IO.Stream sw = MyRequest.GetRequestStream())
                {
                     try
                    {
                        sw.Write(b,  0, b.Length);
                    }
                     catch
                    {
                    }
                }
                HttpWebResponse MyResponse = (HttpWebResponse)MyRequest.GetResponse();
                 return _GetHTML(MyResponse, encoding,  1024);
            }
             catch (Exception erro)
            {
                 if (erro.Message.Contains( " 连接 ") && IAfreshTime - IErrorTime >  0)
                {
                    IErrorTime++;
                     return _PostPage(URL, PostData, encoding, ContentType);
                }
                 throw;
            }
        }
         #endregion
         #endregion
    }
}

 

调用便很方便了，如下：

 

string strProxyAdd =  " www.Proxyxxxx.com ", UserName =  " XXXX ",PassWord =  " XXX ";
int port =  8080;


HttpHelper http =  new HttpHelper();
http.Proxy =  new WebProxy(); // 设置代理
this.http.Proxy.Address =  new Uri( string.Format( " http://{0}:{1} ", strProxyAdd,port)); // 设置代理服务器地址和端口
this.http.Proxy.Credentials =  new NetworkCredential(UserName, PassWord); // 设置代理用户名密码
// http.Proxy = null; // 清空代理

var strPHtml = http.PostPage( " www.xxxx.com ",  " User=ABCD&Pwd=DEF "); // 向www.xxxx.com POST数据User=ABCD&Pwd=DEF

var strHtml = http.GetHTML( " www.xxxx.com ",  " */* ", Encoding.UTF8,  20480); // 从www.xxxx.com获取HTML数据，并用UTF8进行编码

由于Cookie在一个实例中是共用的，在一些场景下可以先POST登录后再GET需要登录才能进入的页面信息。