通过 post 方法的 Web 请求返回 404 Not Found

Question

就像标题所说的那样，我试图通过发布到某个页面的方式提出请求。首先使用谷歌开发工具检查请求的参数，我可以弄清楚这一点（我不确定我是否将所有正确的参数都放在我的帖子字符串中 - 检查图像以获取更多信息）。我在 www 周围找到了很多示例，但没有人使用它，我不知道出了什么问题，我会像往常一样提供一些帮助:)。

请求标头

表单数据

这是我的代码：

string email = "xxxxx";
string password = "xxxxx";

string LOGIN_URL = "https://intranet.cibertec.edu.pe/LoginBolsa/LoginBolsaCIB.aspx";

CookieContainer cookies = new CookieContainer();

HttpWebRequest webRequest = WebRequest.Create(LOGIN_URL) as HttpWebRequest;
webRequest.CookieContainer = cookies;
StreamReader responseReader = new StreamReader(
      webRequest.GetResponse().GetResponseStream()
   );
string responseData = responseReader.ReadToEnd();
responseReader.Close();

string postString = string.Format("ctl00$ContentPlaceHolder1$Login1$UserName={0}&ctl00$ContentPlaceHolder1$Login1$Password={1}&ctl00$ContentPlaceHolder1$Login1$LoginButton={2}&hdnOrigen={3}&hdnLinea={4}&Pagina_Principal={5}", email, password, "Ingresar", "bolsa", "I", "LoginBolsaCIB.aspx");


webRequest = WebRequest.Create(LOGIN_URL) as HttpWebRequest;
webRequest.Method = "POST";
webRequest.ContentType = "application/x-www-form-urlencoded";
webRequest.CookieContainer = cookies;


StreamWriter requestWriter = new StreamWriter(webRequest.GetRequestStream());
requestWriter.Write(postString);
requestWriter.Close();

responseReader = new StreamReader(webRequest.GetResponse().GetResponseStream());
responseData = responseReader.ReadToEnd();
responseReader.Close();

Response.Write(responseData);

Answer 1

这是因为缺少 __ViewState 参数。这个参数是隐藏的表单字段，需要为每个请求附加。

int start = responseData.IndexOf("value=\"", responseData.IndexOf("name=\"__VIEWSTATE\""));
int end = responseData.IndexOf("/>", start);
string viewState = responseData.Substring(start + 7, end - start - 9);
string postString = string.Format("ctl00$ContentPlaceHolder1$Login1$UserName={0}&ctl00$ContentPlaceHolder1$Login1$Password={1}&ctl00$ContentPlaceHolder1$Login1$LoginButton={2}&hdnOrigen={3}&hdnLinea={4}&Pagina_Principal={5}", email, password, "Ingresar", "bolsa", "I", "LoginBolsaCIB.aspx");
postString += String.Concat("&__VIEWSTATE=", viewState);