Using WebRequest with a post method

[Glass Half Full]

I'm trying to get the WebRequest object working with a using post. I imagine I doing something simple and obvious wrong but I just don't see it.
I've included the code that is at the heart of what I'm doing. When I run this using "get" method ("m_HTMLmethod = "get"), everything works mostly as expected. I say mostly because I don't understand why it sends two unauthorized requests. In Fiddler what I see is the first unauth request (expected), a 401 returned, I'm prompted for a userid/password, but then I see another unauth request and another 401 returned, then it sends the authorizied request (header: "Authorization: Basic aWRi..."), even though I have PreAuthenticate set to true (perhaps that doesn't do what I think it does). In any case with the "get" I'm able to eventually read the expected HTML response.


When I try this code using "post", I'm prompted for credentials and I see (in Fiddler) the two unauthorized requests, then I get back the following (WebException):

"The underlying connection was closed: An unexpected error occurred on a send."

Is there a trick (or do I have an bug) in getting WebRequest to work as a post?

Thanks


//---- Code fragment -----
StringBuilder sb = new StringBuilder();

foreach (string name in m_parms.Keys) {
ArrayList al = (ArrayList) m_parms[name];
for (int i = 0; i < al.Count; i++) {
string v = (string) al;
if (v == null) { v = ""; }
sb.Append(name + "=" + System.Web.HttpUtility.UrlEncode(v) + "&");
}
}
string args = sb.ToString();

WebResponse wrp = null;
try {
GetCreds gc = new GetCreds();
wrp = ReadUri(args, gc.Domain, gc.User, gc.Password);
}
catch (WebException e0) {
string msg0 = e0.Message;
if (msg0.IndexOf("401") < 0) {
throw e0;
}

GetCreds gc = new GetCreds();
wrp = e0.Response;
string auth = wrp.Headers.Get("WWW-Authenticate");
string cookie = wrp.Headers.Get("Set-Cookie");
while (true) {
DialogResult dr = gc.ShowDialog();
if (dr == DialogResult.OK) {
try {
wrp = ReadUri(args, gc.Domain, gc.User, gc.Password);
break; // break out of while loop
}
catch (WebException e1) {
string msg1 = e1.Message;
if (msg1.IndexOf("401") < 0) {
throw e1;
}
}
}
else {
return ix;
}
}
}

StreamReader srdr = new StreamReader(wrp.GetResponseStream());
m_browserOutput.SetContent(srdr.ReadToEnd());



//____________________________________________________________________________________________
// this method uses m_HTMLaction and m_HTMLmethod globals and returns WebResponse object
private WebResponse ReadUri(string args, string domain, string user, string password) {
WebRequest wrq = null;
WebResponse wrp = null;

string uri = m_HTMLaction;

// if it's a get append args to uri string
if (m_HTMLmethod == "get") {
uri += "?" + args;
}

//--------------------------------------------------------------------------------
// hook Fiddler up
Uri proxyURI = new Uri("http://127.0.0.1:8888");
GlobalProxySelection.Select = new WebProxy(proxyURI);
//--------------------------------------------------------------------------------

wrq = WebRequest.Create(uri);

wrq.Method = m_HTMLmethod;
wrq.ContentType = "application/x-www-form-urlencoded";

string proxy = System.Configuration.ConfigurationSettings.AppSettings["HTML_ProxyURL"];
if ((proxy != null) && (proxy != "")) {
wrq.Proxy = new WebProxy(proxy);
}

if (user != "") {
if (domain == "") {
wrq.Credentials = new NetworkCredential(user, password);
}
else {
wrq.Credentials = new NetworkCredential(user, password, domain);
}
wrq.PreAuthenticate = true;
}

// if it's a post write args to stream
if (m_HTMLmethod == "post") {
wrq.ContentLength = args.Length + 2;
StreamWriter sw = new StreamWriter(wrq.GetRequestStream());
sw.WriteLine(args);
sw.Flush();
}

wrp = wrq.GetResponse();
return wrp;
}

 

[Peter Huang [MSFT]]

Hi

This article shows how to use the new System.Net classes to create an HTTP
client that uses the HttpWebRequest and HttpWebResponse classes. This
sample shows how to use the following HTTP verbs:
- HEAD

- GET

- POST

- PUT

303436 Visual C# .NET networking classes HTTP Internet client
http://support.microsoft.com/?id=303436

You may have a try to see if that works for you.

If you still have any problem, can you post the information as below?
1. What is your webserver, where did you post to(a aspx page?)
2. Have you tried to post to the webpage directly(e.g. localmachine without
proxy) to isolate the problem.

Based on my knowledge, if we use Windows Integrated Authentication on IIS,
we will get two 401 error before processing, this is by design.

Best regards,

Peter Huang
Microsoft Online Partner Support

Get Secure! - www.microsoft.com/security
This posting is provided "AS IS" with no warranties, and confers no rights.

 

[Glass Half Full]

This was just the info/example I needed. I'm now up and running.
Thanks

 

[Peter Huang [MSFT]]

Hi

I am glad that works for you.

Best regards,

Peter Huang
Microsoft Online Partner Support

Get Secure! - www.microsoft.com/security
This posting is provided "AS IS" with no warranties, and confers no rights.