HttpWebRequest and the POST method from a win form app

[Rachet?]

I am getting a "The remote server returned an error: (400) Bad
Request." error while trying to send data to an asp page. The puzzle
is, if I paste the string I want to send on a browser address box, it
just go fine. From the win form app also it go fine until I happen to
send an xml formatted string as a value. But same go fine through the
browser.

Any help is greatly appreciated.

My code looks like:

string responseString = null;
string strPost=names[0]+"=" + values[0];

for(int i=1;i<values.Length;i++)
{
strPost += ("&" +names+"=" + values);
}

byte[] encodedRequest = Encoding.UTF8.GetBytes(strPost);

HttpWebRequest httpReq =
(HttpWebRequest)WebRequest.Create(myaspPageURL)
httpReq.ContentType =
"application/x-www-form-urlencoded"; httpReq.Timeout = 10000;
httpReq.KeepAlive = true;
httpReq.UserAgent = null;
httpReq.ContentLength = encodedRequest.Length;
httpReq.Method = "POST";

try
{
using (Stream requestStream = httpReq.GetRequestStream())
{
requestStream.Write(encodedRequest, 0, encodedRequest.Length);
requestStream.Close();
}
}

catch ( Exception ex )
{
return "Error in request : " +ex.Message;
}

try
{

HttpWebResponse httpResp = (HttpWebResponse)httpReq.GetResponse();
using (StreamReader sr = new
StreamReader(httpResp.GetResponseStream()) )
{
do
{
responseString = sr.ReadToEnd();
}while(responseString=="");
sr.Close();
}
httpResp.Close ();
/return the response
return responseString;
}
catch ( Exception ex1 )
{
//status=httpResp.StatusDescription ;
return "Error in response : " +ex1.Message ;
}
}

 

[John Timney \(Microsoft MVP\)]

Compare your example to this one and see if you can spot the problem.

http://samples.gotdotnet.com/quickstart/util/srcview.aspx?path=/quickstart/h
owto/samples/net/WebRequests/clientPOST.src

--
Regards

John Timney
Microsoft Regional Director
Microsoft MVP

 

[bruce barker]

you have to url encode the values

strPost += ("&" +names+"=" + HttpUtility.UrlEncode(values));

-- bruce (sqlwork.com)

 

[Scott Allen]

Be careful to UrlEncode the values before you post.

One tool I've found really useful for debugging these sorts of
problems is Fiddler. You can compare what your code sends to the
server with what IE sends to the server and spot the difference.

http://www.bayden.com/Fiddler/help/

 

[Guest]

John,
I tried to use the sample and also the suggestions by the Bruce and scott. I continue to get the error:
System.Net.WebException: The remote server returned an error: (400) Bad Request.
at System.Net.HttpWebRequest.CheckFinalStatus()
at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
at System.Net.HttpWebRequest.GetResponse()
....

Compare your example to this one and see if you can spot the problem.

http://samples.gotdotnet.com/quickstart/util/srcview.aspx?path=/quickstart/h
owto/samples/net/WebRequests/clientPOST.src

--
Regards

John Timney
Microsoft Regional Director
Microsoft MVP

I am getting a "The remote server returned an error: (400) Bad
Request." error while trying to send data to an asp page. The puzzle
is, if I paste the string I want to send on a browser address box, it
just go fine. From the win form app also it go fine until I happen to
send an xml formatted string as a value. But same go fine through the
browser.

Any help is greatly appreciated.

My code looks like:

string responseString = null;
string strPost=names[0]+"=" + values[0];

for(int i=1;i<values.Length;i++)
{
strPost += ("&" +names+"=" + values);
}

byte[] encodedRequest = Encoding.UTF8.GetBytes(strPost);

HttpWebRequest httpReq =
(HttpWebRequest)WebRequest.Create(myaspPageURL)
httpReq.ContentType =
"application/x-www-form-urlencoded"; httpReq.Timeout = 10000;
httpReq.KeepAlive = true;
httpReq.UserAgent = null;
httpReq.ContentLength = encodedRequest.Length;
httpReq.Method = "POST";

try
{
using (Stream requestStream = httpReq.GetRequestStream())
{
requestStream.Write(encodedRequest, 0, encodedRequest.Length);
requestStream.Close();
}
}

catch ( Exception ex )
{
return "Error in request : " +ex.Message;
}

try
{

HttpWebResponse httpResp = (HttpWebResponse)httpReq.GetResponse();
using (StreamReader sr = new
StreamReader(httpResp.GetResponseStream()) )
{
do
{
responseString = sr.ReadToEnd();
}while(responseString=="");
sr.Close();
}
httpResp.Close ();
/return the response
return responseString;
}
catch ( Exception ex1 )
{
//status=httpResp.StatusDescription ;
return "Error in response : " +ex1.Message ;
}
}

 

[Guest]

Thank you so much again. That tool is fabulous. I was able to pinpoint the problem using it. The problem I had was that the requested page had a redirection and I needed to do a manual redirection. Therefore, I just set the autoredirect property to false and handle the redirection later.

Be careful to UrlEncode the values before you post.

One tool I've found really useful for debugging these sorts of
problems is Fiddler. You can compare what your code sends to the
server with what IE sends to the server and spot the difference.

http://www.bayden.com/Fiddler/help/

--
Scott
http://www.OdeToCode.com

I am getting a "The remote server returned an error: (400) Bad
Request." error while trying to send data to an asp page. The puzzle
is, if I paste the string I want to send on a browser address box, it
just go fine. From the win form app also it go fine until I happen to
send an xml formatted string as a value. But same go fine through the
browser.

Any help is greatly appreciated.

My code looks like:

string responseString = null;
string strPost=names[0]+"=" + values[0];

for(int i=1;i<values.Length;i++)
{
strPost += ("&" +names+"=" + values);
}

byte[] encodedRequest = Encoding.UTF8.GetBytes(strPost);

HttpWebRequest httpReq =
(HttpWebRequest)WebRequest.Create(myaspPageURL)
httpReq.ContentType =
"application/x-www-form-urlencoded"; httpReq.Timeout = 10000;
httpReq.KeepAlive = true;
httpReq.UserAgent = null;
httpReq.ContentLength = encodedRequest.Length;
httpReq.Method = "POST";

try
{
using (Stream requestStream = httpReq.GetRequestStream())
{
requestStream.Write(encodedRequest, 0, encodedRequest.Length);
requestStream.Close();
}
}

catch ( Exception ex )
{
return "Error in request : " +ex.Message;
}

try
{

HttpWebResponse httpResp = (HttpWebResponse)httpReq.GetResponse();
using (StreamReader sr = new
StreamReader(httpResp.GetResponseStream()) )
{
do
{
responseString = sr.ReadToEnd();
}while(responseString=="");
sr.Close();
}
httpResp.Close ();
/return the response
return responseString;
}
catch ( Exception ex1 )
{
//status=httpResp.StatusDescription ;
return "Error in response : " +ex1.Message ;
}
}

 

[Scott Allen]

That's great. Glad you have it working.

--s

Thank you so much again. That tool is fabulous. I was able to pinpoint the problem using it. The problem I had was that the requested page had a redirection and I needed to do a manual redirection. Therefore, I just set the autoredirect property to false and handle the redirection later.

Be careful to UrlEncode the values before you post.

One tool I've found really useful for debugging these sorts of
problems is Fiddler. You can compare what your code sends to the
server with what IE sends to the server and spot the difference.

http://www.bayden.com/Fiddler/help/

--
Scott
http://www.OdeToCode.com

I am getting a "The remote server returned an error: (400) Bad
Request." error while trying to send data to an asp page. The puzzle
is, if I paste the string I want to send on a browser address box, it
just go fine. From the win form app also it go fine until I happen to
send an xml formatted string as a value. But same go fine through the
browser.

Any help is greatly appreciated.

My code looks like:

string responseString = null;
string strPost=names[0]+"=" + values[0];

for(int i=1;i<values.Length;i++)
{
strPost += ("&" +names+"=" + values);
}

byte[] encodedRequest = Encoding.UTF8.GetBytes(strPost);

HttpWebRequest httpReq =
(HttpWebRequest)WebRequest.Create(myaspPageURL)
httpReq.ContentType =
"application/x-www-form-urlencoded"; httpReq.Timeout = 10000;
httpReq.KeepAlive = true;
httpReq.UserAgent = null;
httpReq.ContentLength = encodedRequest.Length;
httpReq.Method = "POST";

try
{
using (Stream requestStream = httpReq.GetRequestStream())
{
requestStream.Write(encodedRequest, 0, encodedRequest.Length);
requestStream.Close();
}
}

catch ( Exception ex )
{
return "Error in request : " +ex.Message;
}

try
{

HttpWebResponse httpResp = (HttpWebResponse)httpReq.GetResponse();
using (StreamReader sr = new
StreamReader(httpResp.GetResponseStream()) )
{
do
{
responseString = sr.ReadToEnd();
}while(responseString=="");
sr.Close();
}
httpResp.Close ();
/return the response
return responseString;
}
catch ( Exception ex1 )
{
//status=httpResp.StatusDescription ;
return "Error in response : " +ex1.Message ;
}
}