We Keep Coding

HttpWebRequest get unauthorized exception

Trying to call a remote server using the following code I get always the unauthorized exception from the server:
HttpWebRequest webRequest;
var myURI = "https://myURI";
webRequest = (HttpWebRequest)WebRequest.Create(myURI);
webRequest.Method = "GET";
string myCredentials = Convert.ToBase64String(ASCIIEncoding.ASCII.GetBytes("myUsername" + ":" + "myPassword"));
webRequest.Headers.Add("Authorization", "Basic " + myCredentials);
HttpWebResponse webResponse;
webResponse = (HttpWebResponse)webRequest.GetResponse();
string response = string.Empty;
using (StreamReader sr = new StreamReader(webResponse.GetResponseStream()))
{
response = sr.ReadToEnd();
sr.Close();
}
System.Net.WebException: 'The remote server returned an error: (401) Unauthorized.'
WWW-Authenticate: Basic realm="geoserver"
Cache-Control: proxy-revalidate
Connection: Keep-Alive
Set-Cookie: BCSI-CS-**********=1; Path=/
Proxy-Support: Session-based-authentication
Content-Type: text/plain; charset=UTF-8
Content-Length: 23
It is a litte bit weird because, if I try (almost) the same thing via postman, it works and i get the correct response from the remote server (without 401).
I've also tried other ways like the follwing code, but nothing helps:
CredentialCache cc = new CredentialCache();
cc.Add(
new Uri("https://mywebserver/webpage"),
"Basic", //also tried NTLM
new NetworkCredential("user", "password"));
webRequest.Credentials = cc;
If I try to call an other server with the same code it works.

As you can see in the Exception, has a Session-based-authentication. The problem is: There is no documentation for the reverse proxy and I cannot find an endpoint in order to get a clean cookie. As workaround i've tried the fllowing code and it works now.
It's maybe not the best way to set the Cookie as HttpHeader.
static void Main(string[] args)
{
HttpWebRequest webRequest = CreateWebRequest();
string cookie = null;
HttpWebResponse webResponse;
try
{
webResponse = (HttpWebResponse) webRequest.GetResponse();
}
catch (WebException ex)
{
var headers = (WebHeaderCollection)ex.Response.GetType().GetProperty("Headers").GetValue(ex.Response, null);
cookie = headers.Get("Set-Cookie");
webRequest = CreateWebRequest();
webRequest.Headers.Add("Cookie", cookie);
webResponse = (HttpWebResponse) webRequest.GetResponse();
}
string response = string.Empty;
using (StreamReader sr = new StreamReader(webResponse.GetResponseStream()))
{
response = sr.ReadToEnd();
sr.Close();
}
}
private static HttpWebRequest CreateWebRequest()
{
HttpWebRequest webRequest;
var myURI = "https://myURI";
webRequest = (HttpWebRequest)WebRequest.Create(myURI);
webRequest.Method = "GET";
string myCredentials = Convert.ToBase64String(ASCIIEncoding.ASCII.GetBytes("myUsername" + ":" + "myPassword"));
webRequest.Headers.Add("Authorization", "Basic " + myCredentials);
return webRequest;
}

HttpWebRequest Auth Post Request in c#

i'am using burp suit to check the requests and i m trying to convertthis to c# code
POST /sso HTTP/1.1
Host: account.ankama.com
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: fr,fr-FR;q=0.8,en-US;q=0.5,en;q=0.3
Referer: http://www.dofus.com/fr
Cookie: LANG=fr; _ga=GA1.1.1197518596.1489526959; SID=452EDCF3C4BD32057F9F08254BE40001
Connection: close
Upgrade-Insecure-Requests: 1
Content-Type: application/x-www-form-urlencoded
Content-Length: 102
action=login&from=http%3A%2F%2Fwww.dofus.com%2Ffr&login=user123&password=password1232F&remember=1
So i tried to :
HttpWebRequest Request = (HttpWebRequest)WebRequest.Create("https://account.ankama.com/sso?action=login&from=https%3A%2F%2Faccount.ankama.com%2Ffr%2Fsecurite%2Fmode-restreint%3Ff%3Dhttps%3A%2F%2Faccount.ankama.com%2Ffr%2Fidentification%3Ff%3Dhttps%3A%2F%2Faccount.ankama.com%2Ffr%2Fcompte%2Finformations&login=user111&password=password1472F");
Request.ContentType = "application/x-www-form-urlencoded";
Request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
Request.UserAgent = "Mozilla/5.0 (Windows NT 6.3; WOW64; rv:51.0) Gecko/20100101 Firefox/51.0";
Request.Host = "account.ankama.com";
Request.Referer = "https://account.ankama.com/fr/votre-compte/profil";
Request.Method = "POST";
Request.AllowAutoRedirect = true;
Request.CookieContainer = new CookieContainer();
//quest.Credentials = new NetworkCredential("user123", "passowrd123");
using (HttpWebResponse response = (HttpWebResponse)Request.GetResponse())
{
using (Stream stream = response.GetResponseStream())
{
StreamReader reader = new StreamReader(stream);
StreamWriter writer = new StreamWriter("odm.html");
writer.Write(reader.ReadToEnd());
writer.Close();
reader.Close();
Console.WriteLine("Done");
}
}
Console.ReadKey();
in the file odm.html I m checking if the html code contain "My account" that shown when the user is actually logged in .
but this doesnt seems to be working for some reasons that i still don't know .
i made some research to about HTTP status code but in my brup suit after trying to login in with an actual exisiting account and a none valid account it gives the same http code 302 with a different Content Length .
EDIT:
the issue is i don't find 'my account' in the html file , i only find the page where the user is going to login

You are trying to send request body in query string, you are setting the request method as POST but you are not sending the body. The request url should be:
https://account.ankama.com/sso
And you need to set request body before sending the request:
var bytes = Encoding.UTF8.GetBytes("action=login&from=http%3A%2F%2Fwww.dofus.com%2Ffr&login=user123&password=password1232F&remember=1");
request.ContentLength = bytes.Length;
using (var stream = request.GetRequestStream())
{
stream.Write(bytes, 0, bytes.Length);
}

Access website with C# POST

I am trying to access the data on a website using some C# code. From a browser, a user would go to http://www.hkexnews.hk/sdw/search/search_sdw.asp, put in a date (17 May 2016) and a stock code ("00001") and be taken to a table with the relevant data.
I have used a Firefox add-on (LiveHTTPHeaders) to see that this process produces the following POST request:
http://www.hkexnews.hk/sdw/search/search_sdw.asp
POST /sdw/search/search_sdw.asp HTTP/1.1
Host: www.hkexnews.hk
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:46.0) Gecko/20100101 Firefox/46.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://www.hkexnews.hk/sdw/search/search_sdw.asp
Cookie: ASPSESSIONIDCASQQTQQ=FOLELNMCLAOEPAAEMIICCPAN; TS0161f2e5=017038eb4956ab204b9c8ba8c23ae9307c7879ba5fccd4664528a1407b7fab58353e89b27052a3d4d4df3b4b47034b5a31085f2c11
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 341
txt_today_d=20&txt_today_m=5&txt_today_y=2016&current_page=1&stock_market=HKEX&IsExist_Slt_Stock_Id=False&IsExist_Slt_Part_Id=False&rdo_SelectSortBy=Shareholding&sessionToken=1458.568&sel_ShareholdingDate_d=17&sel_ShareholdingDate_m=05&sel_ShareholdingDate_y=2016&txt_stock_code=00001&txt_stock_name=&txt_ParticipantID=&txt_Participant_name=
HTTP/1.1 200 OK
Cache-Control: private
Pragma: No-Cache
Content-Length: 300802
Content-Type: text/html
Expires: 0
X-Powered-By: ASP.NET
Date: Fri, 20 May 2016 04:58:57 GMT
My code:
string PostData = "txt_today_d=20&txt_today_m=5&txt_today_y=2016&current_page=1&stock_market=HKEX&IsExist_Slt_Stock_Id=False&IsExist_Slt_Part_Id=False&rdo_SelectSortBy=Shareholding&sessionToken=1458.568&sel_ShareholdingDate_d=17&sel_ShareholdingDate_m=05&sel_ShareholdingDate_y=2016&txt_stock_code=00001&txt_stock_name=&txt_ParticipantID=&txt_Participant_name=";
byte[] ByteArray = Encoding.UTF8.GetBytes(PostData);
HttpWebRequest Request = (HttpWebRequest)WebRequest.Create("http://www.hkexnews.hk/sdw/search/search_sdw.asp");
Uri Target = new Uri("http://www.hkexnews.hk/sdw/search/search_sdw.asp");
Request.Method = "POST";
Request.Host = "www.hkexnews.hk";
Request.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:46.0) Gecko/20100101 Firefox/46.0";
Request.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
WebHeaderCollection Headers = Request.Headers;
Headers.Add("Accept-Language", "en-US,en;q=0.5");
Headers.Add("Accept-Encoding", "gzip, deflate");
Request.Referer = "http://www.hkexnews.hk/sdw/search/search_sdw.asp";
Request.CookieContainer = new CookieContainer();
Request.CookieContainer.Add(new Cookie("ASPSESSIONIDCASQQTQQ", "FOLELNMCLAOEPAAEMIICCPAN") { Domain = Target.Host });
Request.CookieContainer.Add(new Cookie("TS0161f2e5", "017038eb49a575136721aebc3f3ef14ec9c810d2e25d5e909be6fe49639ec38eec624237bf9759851675d091f3a4ed0ebc3d8bb3d2") { Domain = Target.Host });
Request.KeepAlive = true;
Request.ContentType = "Content-Type: application/x-www-form-urlencoded";
Request.ContentLength = ByteArray.Length;
Stream dataStream = Request.GetRequestStream();
// Write the data to the request stream.
dataStream.Write(ByteArray, 0, ByteArray.Length);
// Close the Stream object.
dataStream.Close();
// Get the response.
WebResponse response = Request.GetResponse();
// Display the status.
Console.WriteLine(((HttpWebResponse)response).StatusDescription);
// Get the stream containing content returned by the server.
dataStream = response.GetResponseStream();
// Open the stream using a StreamReader for easy access.
StreamReader reader = new StreamReader(dataStream);
// Read the content.
string responseFromServer = reader.ReadToEnd();
// Display the content.
Console.WriteLine(responseFromServer);
// Clean up the streams.
reader.Close();
dataStream.Close();
response.Close();
What this code appears to do is simply spit out the Html of the original search screen instead of taking me to the results.
Edit: I also tried doing the same with the HttpClient class, as below:
using (var client = new HttpClient())
{
client.BaseAddress = new Uri("http://www.hkexnews.hk/sdw/search/search_sdw.asp");
var content = new FormUrlEncodedContent(new[]
{
new KeyValuePair<string, string>("txt_today_d", "20"),
new KeyValuePair<string, string>("txt_today_m", "5"),
new KeyValuePair<string, string>("txt_today_y", "2016"),
new KeyValuePair<string, string>("current_page", "1"),
new KeyValuePair<string, string>("stock_market", "HKEX"),
new KeyValuePair<string, string>("IsExist_Slt_Stock_Id", "False"),
new KeyValuePair<string, string>("IsExist_Slt_Part_Id", "False"),
new KeyValuePair<string, string>("rdo_SelectSortBy", "Shareholding"),
new KeyValuePair<string, string>("sessionToken", "1458.568"),
new KeyValuePair<string, string>("sel_ShareholdingDate_d", "17"),
new KeyValuePair<string, string>("sel_ShareholdingDate_m", "05"),
new KeyValuePair<string, string>("sel_ShareholdingDate_y", "2016"),
new KeyValuePair<string, string>("txt_stock_code", "00001"),
new KeyValuePair<string, string>("txt_stock_name", ""),
new KeyValuePair<string, string>("txt_ParticipantID", ""),
new KeyValuePair<string, string>("txt_Participant_name", "")
});
var result = client.PostAsync("/sdw/search/search_sdw.asp", content).Result;
string resultContent = result.Content.ReadAsStringAsync().Result;
Console.WriteLine(resultContent);
This produces the same result (Html of original form)

Because something wrong in your request(maybe cookie is not correct) and your request was redirected to original website.
HTTP/1.1 302 Object moved
Cache-Control: private
Pragma: No-Cache
Content-Length: 135
Content-Type: text/html
Expires: 0
Location: search_sdw.asp
X-Powered-By: ASP.NET
Date: Fri, 20 May 2016 07:58:52 GMT
<head><title>Object moved</title></head>
<body><h1>Object Moved</h1>This object may be found here.</body>

Internal server error on webresponse while posting data but works using a browser C#

I am trying to post a form using HttpWebRequest but get an internal server error. I have tried setting useragent in the request but no success.
Here is the url which has got the form.
https://portal.llg.de/tracking/xml/sender.asp?cust=anonym_
and this is my sample code
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.IO;
namespace postdata
{
public class RequestManager
{
public static string LastResponse { protected set; get; }
public static void Main(string[] args)
{
System.Net.ServicePointManager.Expect100Continue = false;
string content = "XML=<VORGANG><KUNDE>6400320</KUNDE><LIEFADR>..... Tokio, Japan</LIEFADR><POS NUMMER='1'><ARTNR>9000032</ARTNR><MENGE>10</MENGE><BESTAND>25</BESTAND></POS><POS NUMMER='2'><ARTNR>9161161</ARTNR><MENGE>100</MENGE><BESTAND>33</BESTAND><TERMIN>20050401</TERMIN><PREIS>80.00</PREIS></POS><VERSAND>80.00</VERSAND></VORGANG>";
string url = "https://portal.llg.de/tracking/xml/receiver.asp?cust=_anonym_";
var response = SendPOSTRequest(url, content, true);
var responsecontent = GetResponseContent(response);
}
public static string GetResponseContent(HttpWebResponse response)
{
if (response == null)
{
throw new ArgumentNullException("response");
}
Stream dataStream = null;
StreamReader reader = null;
string responseFromServer = null;
try
{
// Get the stream containing content returned by the server.
dataStream = response.GetResponseStream();
// Open the stream using a StreamReader for easy access.
reader = new StreamReader(dataStream);
// Read the content.
responseFromServer = reader.ReadToEnd();
// Cleanup the streams and the response.
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
finally
{
if (reader != null)
{
reader.Close();
}
if (dataStream != null)
{
dataStream.Close();
}
response.Close();
}
LastResponse = responseFromServer;
return responseFromServer;
}
public static HttpWebResponse SendPOSTRequest(string uri, string content, bool allowAutoRedirect)
{
HttpWebRequest request = GeneratePOSTRequest(uri, content, allowAutoRedirect);
return GetResponse(request);
}
public static HttpWebRequest GeneratePOSTRequest(string uri, string content, bool allowAutoRedirect)
{
return GenerateRequest(uri, content, "POST", null, null, allowAutoRedirect);
}
internal static HttpWebRequest GenerateRequest(string uri, string content, string method, string login, string password, bool allowAutoRedirect)
{
if (uri == null)
{
throw new ArgumentNullException("uri");
}
// Create a request using a URL that can receive a post.
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(uri);
// Set the Method property of the request to POST.
request.Method = method;
// Set cookie container to maintain cookies
// request.CookieContainer = cookies;
request.AllowAutoRedirect = false;
// If login is empty use defaul credentials
if (string.IsNullOrEmpty(login))
{
// request.Credentials = CredentialCache.DefaultNetworkCredentials;
request.Credentials = CredentialCache.DefaultCredentials;
}
else
{
request.Credentials = new NetworkCredential(login, password);
}
if (method == "POST")
{
// Convert POST data to a byte array.
byte[] byteArray = Encoding.UTF8.GetBytes(content);
// Set the ContentType property of the WebRequest.
request.ContentType = "application/x-www-form-urlencoded";
request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705;)";
// Set the ContentLength property of the WebRequest.
request.ContentLength = byteArray.Length;
// Get the request stream.
Stream dataStream = request.GetRequestStream();
// Write the data to the request stream.
dataStream.Write(byteArray, 0, byteArray.Length);
// Close the Stream object.
dataStream.Close();
}
return request;
}
internal static HttpWebResponse GetResponse(HttpWebRequest request)
{
if (request == null)
{
throw new ArgumentNullException("request");
}
HttpWebResponse response = null;
try
{
response = (HttpWebResponse)request.GetResponse();
}
catch (WebException ex)
{
Console.WriteLine("Web exception occurred. Status code: {0}", ex.Status);
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
return response;
}
}
}

I debugged with fiddler both posts.
Something is weird in the form post. The xml conatains "+" between the tags.
If you use this string the post works.
content = "XML=<VORGANG><KUNDE>6400320</KUNDE><LIEFADR>.....+Tokio,+Japan</LIEFADR><POS+NUMMER=\"1\">++<ARTNR>9000032</ARTNR>++<MENGE>10</MENGE>++<BESTAND>25</BESTAND></POS><POS+NUMMER=\"2\">++<ARTNR>9161161</ARTNR>++<MENGE>100</MENGE>++<BESTAND>33</BESTAND>++<TERMIN>20050401</TERMIN>++<PREIS>80.00</PREIS></POS><VERSAND>80.00</VERSAND></VORGANG>";
Fiddler Debug:
POST https://portal.llg.de/tracking/xml/receiver.asp?cust=_anonym_ HTTP/1.1
Host: portal.llg.de
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20100101 Firefox/22.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: de,en-us;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
DNT: 1
Referer: https://portal.llg.de/tracking/xml/sender.asp?cust=anonym_
Cookie: ASPSESSIONIDSQSACSTQ=CIGFABLBPHPMLBDOPJIKPHJB
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded
Content-Length: 588
XML=%3CVORGANG%3E%0D%0A%3CKUNDE%3E6400320%3C%2FKUNDE%3E%0D%0A%3CLIEFADR%3E.....+Tokio%2C+Japan%3C%2FLIEFADR%3E%0D%0A%3CPOS+NUMMER%3D%221%22%3E%0D%0A++%3CARTNR%3E9000032%3C%2FARTNR%3E%0D%0A++%3CMENGE%3E10%3C%2FMENGE%3E%0D%0A++%3CBESTAND%3E25%3C%2FBESTAND%3E%0D%0A%3C%2FPOS%3E%0D%0A%3CPOS+NUMMER%3D%222%22%3E%0D%0A++%3CARTNR%3E9161161%3C%2FARTNR%3E%0D%0A++%3CMENGE%3E100%3C%2FMENGE%3E%0D%0A++%3CBESTAND%3E33%3C%2FBESTAND%3E%0D%0A++%3CTERMIN%3E20050401%3C%2FTERMIN%3E%0D%0A++%3CPREIS%3E80.00%3C%2FPREIS%3E%0D%0A%3C%2FPOS%3E%0D%0A%3CVERSAND%3E80.00%3C%2FVERSAND%3E%0D%0A%3C%2FVORGANG%3E%0D%0A
if you use url decode to decode the xml="..:"
you get this:
XML=<VORGANG>
<KUNDE>6400320</KUNDE>
<LIEFADR>.....+Tokio,+Japan</LIEFADR>
<POS+NUMMER="1">
++<ARTNR>9000032</ARTNR>
++<MENGE>10</MENGE>
++<BESTAND>25</BESTAND>
</POS>
<POS+NUMMER="2">
++<ARTNR>9161161</ARTNR>
++<MENGE>100</MENGE>
++<BESTAND>33</BESTAND>
++<TERMIN>20050401</TERMIN>
++<PREIS>80.00</PREIS>
</POS>
<VERSAND>80.00</VERSAND>
</VORGANG>

Truncated response received using HttpWebRequest

I'm using the following code to make HttpWebRequests to a web site:
public static HttpWebResponse SendGETRequest(string url, string agent, CookieContainer cookieContainer)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.UserAgent = agent;
request.Method = "GET";
request.ContentType = "text/html";
request.CookieContainer = cookieContainer;
return (HttpWebResponse)request.GetResponse();
}
Everything worked fine with several web pages until I tried with a new one and only received the last part of the page. This is the received response:
<tr>
<td colspan="2" height="5"><spacer type="block" width="100%" height="5"></td>
</tr>
</table>
</td>
</tr>
</table>
</body>
</html>
The header is correct and says that only the received data is sent. The following are the headers of the request and response:
Request:
GET /Broker/Ops/FichaContratoJS.asp?nc=815044&IP=5&YY=2012&M=6&St=0&CC=FESX201206 HTTP/1.1
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.168 Safari/535.19
Content-Type: text/html
Host: www.xxxx.com
Cookie: ASPSESSIONIDACBDCDBT=MGDNMNABOANDMILHBNCIDFCH;Autenticacion=Sid=230fae3d%2De0e2%2D4df1%2D8aa8%2D000fb352eaef&IdUsuarioWeb=xxxx; ASPSESSIONIDACBCCDAT=AFDJMNABAFJDDHABLOLAINDK; ASPSESSIONIDCADCBCAT=CEBJGNABLCALPJLDJFPBMLDE
Response:
HTTP/1.1 200 OK
Date: Wed, 09 May 2012 07:25:03 GMT
Server: Microsoft-IIS/6.0
X-Powered-By: ASP.NET
Pragma: no-cache
**Content-Length: 155**
Content-Type: text/html
Expires: Wed, 09 May 2012 07:24:02 GMT
Set-Cookie: Autenticacion=Sid=230fae3d%2De0e2%2D4df1%2D8aa8%2D000fb352eaef&IdUsuarioWeb=xxxx; path=/
Cache-control: no-cache
Doing the same with a web browser works fine and returns a content length of about 4000 bytes.
Any ideas?
PD: Just in case it matters I'm doing several calls to the SendGETRequest from different threads to the same site but as there are no shared variables I think it shouldn't make a difference.
EDIT: This is the extension I use to extract the text from the Stream:
public static string ReadTextResponse(this Stream stream)
{
int count;
Encoding enconding = System.Text.Encoding.GetEncoding(1252);
System.Text.StringBuilder stringBuilder = new StringBuilder();
byte[] buffer = new byte[1023];
do
{
count = stream.Read(buffer, 0, buffer.Length);
if (count != 0)
{
string tempString = enconding.GetString(buffer, 0, count);
stringBuilder.Append(tempString);
}
}
while (count > 0);
return stringBuilder.ToString();
}
As far as I know it's correct. Also, note that the response header from the server contains the length of the truncated data

I think that you are not using right the HttpWebResponse object.
Maybe you are not closing the request or reading all the response strem.
http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.getresponse.aspx
Your method should be:
public static string SendGETRequest(string url, string agent, CookieContainer cookieContainer)
{
var request = (HttpWebRequest)WebRequest.Create(url);
request.UserAgent = agent;
request.Method = "GET";
request.ContentType = "text/html";
request.CookieContainer = cookieContainer;
string result;
using (var myResponse = (HttpWebResponse) request.GetResponse())
{
using (var stream = myResponse.GetResponseStream())
{
result = null;
if (stream != null)
{
using (var sr = new StreamReader(stream, System.Text.Encoding.UTF8))
{
result = sr.ReadToEnd();
sr.Close();
}
stream.Close();
}
}
myResponse.Close();
}
return result;
}

Incredible ... I was sending the URL /Broker/Ops/FichaContratoJS.asp?nc=815044&IP=5&YY=2012&M=6 and the browser was sending /Broker/Ops/FichaContratoJS.asp?nc=815044&IP=5&YY=2012&M=06& (note the extra 0 on the M parameter (it's a month). Putting there that 0 returned the full page. Sounds like a defect to me

I have run into a similar situation and found that copying the response stream into a MemoryStream seemed to fix my problems.
public static string SendGETRequest(string url, string agent, CookieContainer cookieContainer)
{
var request = (HttpWebRequest)WebRequest.Create(url);
request.UserAgent = agent;
request.Method = "GET";
request.ContentType = "text/html";
request.CookieContainer = cookieContainer;
string result;
using (var myResponse = (HttpWebResponse) request.GetResponse())
{
using (var stream = myResponse.GetResponseStream())
{
result = null;
if (stream != null)
{
MemoryStream memStream = new MemoryStream();
stream.CopyTo(memStream);
memStream.Flush();
stream.Close();
using (var sr = new StreamReader(memStream, System.Text.Encoding.UTF8))
{
result = sr.ReadToEnd();
sr.Close();
}
memStream.Close();
}
}
myResponse.Close();
}
return result;
}