/// <summary>
/// 使用Post方法获取字符串结果
/// </summary>
/// <param name="url"></param>
/// <param name="formItems">Post表单内容</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, List<FormItemModel> formItems, 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();
#region 处理Form表单请求内容
//是否用Form上传文件
var formUploadFile = formItems != null && formItems.Count > 0;
if (formUploadFile)
{
//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";
//文本数据模板
string dataFormdataTemplate =
"\r\n--" + boundary +
"\r\nContent-Disposition: form-data; name=\"{0}\"" +
"\r\n\r\n{1}";
foreach (var item in formItems)
{
string formdata = null;
if (item.IsFile)
{
//上传文件
formdata = string.Format(
fileFormdataTemplate,
item.Key, //表单键
item.FileName);
}
else
{
//上传文本
formdata = string.Format(
dataFormdataTemplate,
item.Key,
item.Value);
}
//统一处理
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);
//写入文件内容
if (item.FileContent != null && item.FileContent.Length>0)
{
using (var stream = item.FileContent)
{
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);
}
else
{
request.ContentType = "application/x-www-form-urlencoded";
}
#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
}
#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;
}
}
}
