Http帮助类

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

namespace WindowsFormsApp9
{
public class HttpHelper
{
//2.提交表单主逻辑实现
/// <summary>
/// 使用Post方法获取字符串结果
/// </summary>
/// <param name="url"></param>
/// <param name="formTexts">Post表单文字内容</param>
/// <param name="formFiles">Post表单文件内容</param>
/// <param name="cookieContainer"></param>
/// <param name="timeOut">默认20秒</param>
/// <param name="encoding">响应内容的编码类型（默认utf-8）</param>
/// <returns></returns>
public static string PostForm(string url, Dictionary<string, string> dic, Dictionary<string, string> formTexts, Dictionary<string, string> formFiles, CookieContainer cookieContainer = null, string refererUrl = null, Encoding encoding = null, int timeOut = 20000)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
#region 初始化请求对象
request.Method = "POST";
request.Timeout = timeOut;
request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
request.KeepAlive = true;
request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.57 Safari/537.36";
if (!string.IsNullOrEmpty(refererUrl))
request.Referer = refererUrl;
if (cookieContainer != null)
request.CookieContainer = cookieContainer;
#endregion

string boundary = "----" + DateTime.Now.Ticks.ToString("x");//分隔符
request.ContentType = string.Format("multipart/form-data; boundary={0}", boundary);
//请求流
var postStream = new MemoryStream();
if (dic != null)
{
StringBuilder builder = new StringBuilder();
int i = 0;
foreach (var item in dic)
{
if (i > 0)
builder.Append("&");
builder.AppendFormat("{0}={1}", item.Key, item.Value);
i++;
}
byte[] data = Encoding.UTF8.GetBytes(builder.ToString());
postStream.Write(data, 0, data.Length);
}
#region 处理Form表单请求内容

//处理文字内容
if (formTexts != null)
{
foreach (var item in formTexts)
{
//文本数据模板
string dataFormdataTemplate =
"\r\n--" + boundary +
"\r\nContent-Disposition: form-data; name=\"{0}\"" +
"\r\n\r\n{1}";

//上传文本
string formdata = string.Format(
dataFormdataTemplate,
item.Key,
item.Value);
//写入信息
byte[] formdataBytes = null;
//第一行不需要换行
if (postStream.Length == 0)
formdataBytes = Encoding.UTF8.GetBytes(formdata.Substring(2, formdata.Length - 2));
else
formdataBytes = Encoding.UTF8.GetBytes(formdata);
postStream.Write(formdataBytes, 0, formdataBytes.Length);
}
}
//处理文件内容
if (formFiles != null)
{
foreach (var item in formFiles)
{
//文件数据模板
string fileFormdataTemplate =
"\r\n--" + boundary +
"\r\nContent-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"" +
"\r\nContent-Type: application/octet-stream" +
"\r\n\r\n";
//上传文件
string formdata = string.Format(
fileFormdataTemplate,
item.Key, //表单键
System.IO.Path.GetFileName(item.Value));
//写入信息
byte[] formdataBytes = null;
//第一行不需要换行
if (postStream.Length == 0)
{
formdataBytes = Encoding.UTF8.GetBytes(formdata.Substring(2, formdata.Length - 2));
}
else
{
formdataBytes = Encoding.UTF8.GetBytes(formdata);
}
postStream.Write(formdataBytes, 0, formdataBytes.Length);

using (var stream = System.IO.File.OpenRead(item.Value))
{
byte[] buffer = new byte[1024];
int bytesRead = 0;
while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) != 0)
{
postStream.Write(buffer, 0, bytesRead);
}
}
}
}
//结尾
var footer = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");
postStream.Write(footer, 0, footer.Length);

#endregion

request.ContentLength = postStream.Length;

#region 输入二进制流
if (postStream != null)
{
postStream.Position = 0;
//直接写入流
Stream requestStream = request.GetRequestStream();

byte[] buffer = new byte[1024];
int bytesRead = 0;
while ((bytesRead = postStream.Read(buffer, 0, buffer.Length)) != 0)
{
requestStream.Write(buffer, 0, bytesRead);
}

////debug
//postStream.Seek(0, SeekOrigin.Begin);
//StreamReader sr = new StreamReader(postStream);
//var postStr = sr.ReadToEnd();
postStream.Close();//关闭文件访问overduetime
}
#endregion

HttpWebResponse response = (HttpWebResponse)request.GetResponse();
if (cookieContainer != null)
{
response.Cookies = cookieContainer.GetCookies(response.ResponseUri);
}

using (Stream responseStream = response.GetResponseStream())
{
using (StreamReader myStreamReader = new StreamReader(responseStream, encoding ?? Encoding.UTF8))
{
string retString = myStreamReader.ReadToEnd();
return retString;
}
}
}
}
}