Post form data using HttpWebRequest

wsplinter picture wsplinter · Feb 5, 2013 · Viewed 222.4k times · Source

I want to post some form data to a specified URL that isn't inside my own web application. It has the same domain, such like "domain.client.nl". The web application has a url "web.domain.client.nl" en the url where I want to post to is "idp.domain.client.nl". But my code does nothing..... does someone knows what I'm doing wrong?

Wouter

StringBuilder postData = new StringBuilder();
postData.Append(HttpUtility.UrlEncode(String.Format("username={0}&", uname)));
postData.Append(HttpUtility.UrlEncode(String.Format("password={0}&", pword)));
postData.Append(HttpUtility.UrlEncode(String.Format("url_success={0}&", urlSuccess)));
postData.Append(HttpUtility.UrlEncode(String.Format("url_failed={0}", urlFailed)));

ASCIIEncoding ascii = new ASCIIEncoding();
byte[] postBytes = ascii.GetBytes(postData.ToString());

// set up request object
HttpWebRequest request;
try
{
    request = (HttpWebRequest)HttpWebRequest.Create(WebSiteConstants.UrlIdp);
}
catch (UriFormatException)
{
    request = null;
}
if (request == null)
    throw new ApplicationException("Invalid URL: " + WebSiteConstants.UrlIdp);

request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = postBytes.Length;
request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";

// add post data to request
Stream postStream = request.GetRequestStream();
postStream.Write(postBytes, 0, postBytes.Length);
postStream.Flush();
postStream.Close();

Answer

user3389691 picture user3389691 · Mar 6, 2014

Both the field name and the value should be url encoded. format of the post data and query string are the same

The .net way of doing is something like this

NameValueCollection outgoingQueryString = HttpUtility.ParseQueryString(String.Empty);
outgoingQueryString.Add("field1","value1");
outgoingQueryString.Add("field2", "value2");
string postdata = outgoingQueryString.ToString();

This will take care of encoding the fields and the value names