今天在用HttpWebResponse类向一个远程页面post数据时，遇到了一个怪问题：通过对比自己post的参数和服务器接收到的值，发现参数中的一个+号被替换成了空格。
造成这个错误的原因在于+号在url中是特殊字符，远程服务器在接受request的时候，把+转成了空格。同样的，如果想post的数据中有&、%等等，也会被服务器转义，所以我们在post的数据的时候，需要先把数据UrlEncode一下。url encode在bs开发中本来是一个很常见的问题。
修改后的post数据的示例代码如下：
public static HttpWebResponse CreatePostHttpResponse(string url, IDictionary 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 = WebRequest.Create(url) as HttpWebRequest;
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
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);
}
//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++;
}
var postData = string.Join("&", parameters.Select(
p => string.Format("{0}={1}", p.Key, System.Web.HttpUtility.UrlEncode(p.Value, requestEncoding))).ToArray());
byte[] data = requestEncoding.GetBytes(postData);
using (Stream stream = request.GetRequestStream())
{
stream.Write(data, 0, data.Length);
}
}
return request.GetResponse() as HttpWebResponse;
}
转播
