Blog Archives

HTTP Post in C# .Net

Why re-invent the wheel? 😉

See below for a few quick examples from the minds over at csharp-online and codeproject.


Note:
Any snippets may have been condensed from their original sources for brevity. See references for original articles.

All examples are in C# .Net.

HTTP Post:

using System.Net;
...
string HttpPost (string uri, string parameters)
{ 
   // parameters: name1=value1&name2=value2	
   WebRequest webRequest = WebRequest.Create (uri);
   //string ProxyString = 
   //   System.Configuration.ConfigurationManager.AppSettings
   //   [GetConfigKey("proxy")];
   //webRequest.Proxy = new WebProxy (ProxyString, true);
   //Commenting out above required change to App.Config
   webRequest.ContentType = "application/x-www-form-urlencoded";
   webRequest.Method = "POST";
   byte[] bytes = Encoding.ASCII.GetBytes (parameters);
   Stream os = null;
   try
   { // send the Post
      webRequest.ContentLength = bytes.Length;   //Count bytes to send
      os = webRequest.GetRequestStream();
      os.Write (bytes, 0, bytes.Length);         //Send it
   }
   catch (WebException ex)
   {
      MessageBox.Show ( ex.Message, "HttpPost: Request error", 
         MessageBoxButtons.OK, MessageBoxIcon.Error );
   }
   finally
   {
      if (os != null)
      {
         os.Close();
      }
   }
 
   try
   { // get the response
      WebResponse webResponse = webRequest.GetResponse();
      if (webResponse == null) 
         { return null; }
      StreamReader sr = new StreamReader (webResponse.GetResponseStream());
      return sr.ReadToEnd ().Trim ();
   }
   catch (WebException ex)
   {
      MessageBox.Show ( ex.Message, "HttpPost: Response error", 
         MessageBoxButtons.OK, MessageBoxIcon.Error );
   }
   return null;
} // end HttpPost 

Intermediate webrequest usage:

using System;
using System.Collections.Specialized;
using System.Net;
using System.Text;
using System.IO;
 
namespace BaseClassNameSpace.Web.BaseServices
{

//This base class provides implementation of request 

//and response methods during Http Calls.
      public class HttpBaseClass
      {
 
            private string UserName;
            private string UserPwd;
            private string ProxyServer;
            private int ProxyPort;
            private string Request;
            
            public HttpBaseClass(string HttpUserName, 
              string HttpUserPwd, string HttpProxyServer, 
              int HttpProxyPort, string HttpRequest)
            {
                  UserName = HttpUserName;
                  UserPwd = HttpUserPwd;
                  ProxyServer = HttpProxyServer;
                  ProxyPort = HttpProxyPort;
                  Request = HttpRequest;
            }
 
/// <summary>

// This method creates secure/non secure web
// request based on the parameters passed.
            public virtual HttpWebRequest CreateWebRequest(string uri, 
              NameValueCollection collHeader, 
              string RequestMethod, bool NwCred)
            {
                  HttpWebRequest webrequest = 
                   (HttpWebRequest) WebRequest.Create(uri);
                  webrequest.KeepAlive = false;
                  webrequest.Method = RequestMethod;
 
                  int iCount = collHeader.Count;
                  string key;
                  string keyvalue;
 
                  for (int i=0; i < iCount; i++)
                  {
                        key = collHeader.Keys[i];
                        keyvalue = collHeader[i];
                        webrequest.Headers.Add(key, keyvalue);
                  }
                  
                  webrequest.ContentType = "text/html"; 
                  //"application/x-www-form-urlencoded";

                  if (ProxyServer.Length > 0)
                  {
                     webrequest.Proxy = new 
                      WebProxy(ProxyServer,ProxyPort);
                  }
                  webrequest.AllowAutoRedirect = false;
 
                  if (NwCred)
                  {
                      CredentialCache wrCache = 
                              new CredentialCache();
                      wrCache.Add(new Uri(uri),"Basic",
                        new NetworkCredential(UserName,UserPwd));
                      webrequest.Credentials = wrCache;
                  }
                  //Remove collection elements

                  collHeader.Clear();
                  return webrequest;
            }//End of secure CreateWebRequest

            
            // This method retreives redirected URL from

            // response header and also passes back

            // any cookie (if there is any)

            public virtual string GetRedirectURL(HttpWebResponse 
                 webresponse, ref string Cookie)
            {
                  string uri="";
 
                  WebHeaderCollection headers = webresponse.Headers;
                  
                  if ((webresponse.StatusCode == HttpStatusCode.Found) || 
                    (webresponse.StatusCode == HttpStatusCode.Redirect) ||
                    (webresponse.StatusCode == HttpStatusCode.Moved) ||
                    (webresponse.StatusCode == HttpStatusCode.MovedPermanently))
                  {
                        // Get redirected uri

                        uri = headers["Location"] ;
                        uri = uri.Trim();
                  }
 
                  //Check for any cookies

                  if (headers["Set-Cookie"] != null)
                  {
                        Cookie = headers["Set-Cookie"];  
                  }
                  //                string StartURI = "http:/";

//                if (uri.Length > 0 && uri.StartsWith(StartURI)==false)

//                {

//                      uri = StartURI + uri;

//                }

                  return uri;
            }//End of GetRedirectURL method

            public virtual string GetFinalResponse(string ReUri, 
             string Cookie, string RequestMethod, bool NwCred)
            {
                  NameValueCollection collHeader = 
                        new NameValueCollection();
 
                  if (Cookie.Length > 0)
                  {
                        collHeader.Add("Cookie",Cookie);
                  }
 
                  HttpWebRequest webrequest = 
                    CreateWebRequest(ReUri,collHeader, 
                    RequestMethod, NwCred);
                        
                  BuildReqStream(ref webrequest);
 
                  HttpWebResponse webresponse;
 
                  webresponse = (HttpWebResponse)webrequest.GetResponse();
 
                  Encoding enc = System.Text.Encoding.GetEncoding(1252);
                  StreamReader loResponseStream = new 
                    StreamReader(webresponse.GetResponseStream(),enc);
 
                  string Response = loResponseStream.ReadToEnd();
 
                  loResponseStream.Close();
                  webresponse.Close();
                  
                  return Response;
            }
 
            private void BuildReqStream(ref HttpWebRequest webrequest)
            {
                  byte[] bytes = Encoding.ASCII.GetBytes(Request);
                  webrequest.ContentLength=bytes.Length;
 
                  Stream oStreamOut = webrequest.GetRequestStream();
                  oStreamOut.Write(bytes,0,bytes.Length);
                  oStreamOut.Close();
            }
      }
}//End of HttpBaseClass class

References:
Csharp-online, “HTTP Post”, http://en.csharp-online.net/HTTP_Post
Codeproject, “How to use HttpWebRequest and HttpWebResponse in .NET”, http://www.codeproject.com/KB/IP/httpwebrequest_response.aspx

Facebook is down!

As of approx. October 6, 12:30 AM EST GMT -5 Facebook HTTP services seemed to have gone down.

Ping tests were successful during this time, however, attempts to load the website resulted in timeouts.

More updates tomorrow morning after some official announcements have been made. My initial speculation is botnet and/or DoS attack but this is very preliminary.

Update 12:49 AM EST GMT -5

Looks like downrightnow.com is down as well…

Update 10:15 AM EST GMT -5

Some other sites also seem to have gone down, reddit, apple store and digg among others.