C# Http请求（GET/HTTP/HTTPS）

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

namespace BaiduCang
{
/// <summary>
/// 有关HTTP请求的辅助类
/// </summary>
public class HttpWebResponseUtility
{
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</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></returns>
public static HttpWebResponse CreateGetHttpResponse(string url,int? timeout, string userAgent,CookieCollection cookies)
{
if (string.IsNullOrEmpty(url))
{
throw new ArgumentNullException("url");
}
HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
request.Method = "GET";
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>
/// <returns></returns>
public static HttpWebResponse CreatePostHttpResponse(string url,IDictionary<string,string> parameters,int? timeout, string userAgent,Encoding requestEncoding,CookieCollection cookies)
{
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);
request = WebRequest.Create(url) as HttpWebRequest;
request.ProtocolVersion=HttpVersion.Version10;
}
else
{
request = WebRequest.Create(url) as HttpWebRequest;
}
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";

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

if (timeout.HasValue)
{
request.Timeout = timeout.Value;
}
if (cookies != null)
{
request.CookieContainer = new CookieContainer();
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, parameters[key]);
}
else
{
buffer.AppendFormat("{0}={1}", key, 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;
}

private static bool CheckValidationResult(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)
{
return true; //总是接受
}
}
}