HttpWebRequest.BeginGetResponse Method

public override IAsyncResult BeginGetResponse (
	AsyncCallback callback,
	Object state
)

public IAsyncResult BeginGetResponse (
	AsyncCallback callback, 
	Object state
)

public override function BeginGetResponse (
	callback : AsyncCallback, 
	state : Object
) : IAsyncResult

Not applicable.

using System;
using System.Net;
using System.IO;
using System.Text;
using System.Threading;


public class RequestState
{
  // This class stores the State of the request.
  const int BUFFER_SIZE = 1024;
  public StringBuilder requestData;
  public byte[] BufferRead;
  public HttpWebRequest request;
  public HttpWebResponse response;
  public Stream streamResponse;
  public RequestState()
  {
    BufferRead = new byte[BUFFER_SIZE];
    requestData = new StringBuilder("");
    request = null;
    streamResponse = null;
  }
}

class HttpWebRequest_BeginGetResponse
{
  public static ManualResetEvent allDone= new ManualResetEvent(false);
  const int BUFFER_SIZE = 1024;
  const int DefaultTimeout = 2 * 60 * 1000; // 2 minutes timeout
 
  // Abort the request if the timer fires.
  private static void TimeoutCallback(object state, bool timedOut) { 
      if (timedOut) {
          HttpWebRequest request = state as HttpWebRequest;
          if (request != null) {
              request.Abort();
          }
      }
  }

  static void Main()
  {  
   
    try
    {
      // Create a HttpWebrequest object to the desired URL. 
      HttpWebRequest myHttpWebRequest= (HttpWebRequest)WebRequest.Create("http://www.contoso.com");

    
  /**
    * If you are behind a firewall and you do not have your browser proxy setup
    * you need to use the following proxy creation code.

      // Create a proxy object.
      WebProxy myProxy = new WebProxy();

      // Associate a new Uri object to the _wProxy object, using the proxy address
      // selected by the user.
      myProxy.Address = new Uri("http://myproxy");
       
        
      // Finally, initialize the Web request object proxy property with the _wProxy
      // object.
      myHttpWebRequest.Proxy=myProxy;
    ***/

      // Create an instance of the RequestState and assign the previous myHttpWebRequest
      // object to its request field.  
      RequestState myRequestState = new RequestState();  
      myRequestState.request = myHttpWebRequest;


      // Start the asynchronous request.
      IAsyncResult result=
        (IAsyncResult) myHttpWebRequest.BeginGetResponse(new AsyncCallback(RespCallback),myRequestState);

      // this line implements the timeout, if there is a timeout, the callback fires and the request becomes aborted
      ThreadPool.RegisterWaitForSingleObject (result.AsyncWaitHandle, new WaitOrTimerCallback(TimeoutCallback), myHttpWebRequest, DefaultTimeout, true);

      // The response came in the allowed time. The work processing will happen in the 
      // callback function.
      allDone.WaitOne();
      
      // Release the HttpWebResponse resource.
      myRequestState.response.Close();
    }
    catch(WebException e)
    {
      Console.WriteLine("\nMain Exception raised!");
      Console.WriteLine("\nMessage:{0}",e.Message);
      Console.WriteLine("\nStatus:{0}",e.Status);
      Console.WriteLine("Press any key to continue..........");
    }
    catch(Exception e)
    {
      Console.WriteLine("\nMain Exception raised!");
      Console.WriteLine("Source :{0} " , e.Source);
      Console.WriteLine("Message :{0} " , e.Message);
      Console.WriteLine("Press any key to continue..........");
      Console.Read();
    }
  }
  private static void RespCallback(IAsyncResult asynchronousResult)
  {  
    try
    {
      // State of request is asynchronous.
      RequestState myRequestState=(RequestState) asynchronousResult.AsyncState;
      HttpWebRequest  myHttpWebRequest=myRequestState.request;
      myRequestState.response = (HttpWebResponse) myHttpWebRequest.EndGetResponse(asynchronousResult);
      
      // Read the response into a Stream object.
      Stream responseStream = myRequestState.response.GetResponseStream();
      myRequestState.streamResponse=responseStream;
      
      // Begin the Reading of the contents of the HTML page and print it to the console.
      IAsyncResult asynchronousInputRead = responseStream.BeginRead(myRequestState.BufferRead, 0, BUFFER_SIZE, new AsyncCallback(ReadCallBack), myRequestState);
      return;
    }
    catch(WebException e)
    {
      Console.WriteLine("\nRespCallback Exception raised!");
      Console.WriteLine("\nMessage:{0}",e.Message);
      Console.WriteLine("\nStatus:{0}",e.Status);
    }
    allDone.Set();
  }
  private static  void ReadCallBack(IAsyncResult asyncResult)
  {
    try
    {

    RequestState myRequestState = (RequestState)asyncResult.AsyncState;
    Stream responseStream = myRequestState.streamResponse;
    int read = responseStream.EndRead( asyncResult );
    // Read the HTML page and then print it to the console.
    if (read > 0)
    {
      myRequestState.requestData.Append(Encoding.ASCII.GetString(myRequestState.BufferRead, 0, read));
      IAsyncResult asynchronousResult = responseStream.BeginRead( myRequestState.BufferRead, 0, BUFFER_SIZE, new AsyncCallback(ReadCallBack), myRequestState);
      return;
    }
    else
    {
      Console.WriteLine("\nThe contents of the Html page are : ");
      if(myRequestState.requestData.Length>1)
      {
        string stringContent;
        stringContent = myRequestState.requestData.ToString();
        Console.WriteLine(stringContent);
      }
      Console.WriteLine("Press any key to continue..........");
      Console.ReadLine();
      
      responseStream.Close();
    }

    }
    catch(WebException e)
    {
      Console.WriteLine("\nReadCallBack Exception raised!");
      Console.WriteLine("\nMessage:{0}",e.Message);
      Console.WriteLine("\nStatus:{0}",e.Status);
    }
    allDone.Set();

  }

import System.*;
import System.Net.*;
import System.IO.*;
import System.Text.*;
import System.Threading.*;

public class RequestState
{
    // This class stores the State of the request.
    private final int BUFFER_SIZE = 1024;
    public StringBuilder requestData;
    public ubyte bufferRead[];
    public HttpWebRequest request;
    public HttpWebResponse response;
    public Stream streamResponse;
   
    public RequestState() 
    {
        bufferRead = new ubyte[BUFFER_SIZE];
        requestData = new StringBuilder("");
        request = null;
        streamResponse = null;
    } //RequestState
} //RequestState

class HttpWebRequest_BeginGetResponse
{
    public static ManualResetEvent allDone = new ManualResetEvent(false);
    private static final int BUFFER_SIZE = 1024;
    private static int defaultTimeout = 2 * 60 * 1000; // 2 minutes timeout
    
    // Abort the request if the timer fires.
    private static void TimeoutCallback(Object state, boolean timedOut)
    {
        if (timedOut ) {
            HttpWebRequest request = (HttpWebRequest)state;
            if (request  != null) {
                request.Abort();
            }
        }
    } //TimeoutCallback
   
       public static void main(String[] args)
    {
        try {
            // Create a HttpWebrequest object to the desired URL. 
            HttpWebRequest myHttpWebRequest =((HttpWebRequest)
                (WebRequest.Create("http://www.contoso.com")));
            /**
                 If you are behind a firewall and you do not have your browser 
                 proxy setup you need to use the following proxy creation code.

                // Create a proxy object.
                WebProxy myProxy = new WebProxy();

                // Associate a new Uri object to the _wProxy object, using the 
                // proxy address selected by the user.
                myProxy.set_Address(new Uri("http://myproxy"));

                // Finally, initialize the Web request object proxy property
                // with the _wProxy object.
                myHttpWebRequest.set_Proxy(myProxy);
             */

            // Create an instance of the RequestState and assign the previous 
            // myHttpWebRequest object to it's request field.  
            RequestState myRequestState = new RequestState();
            myRequestState.request = myHttpWebRequest;

            // Start the asynchronous request.
            IAsyncResult result = 
                ((IAsyncResult)(myHttpWebRequest.BeginGetResponse(
                new AsyncCallback(RespCallback), myRequestState)));

            // this line impliments the timeout, if there is a timeout, 
            // the callback fires and the request becomes aborted
            ThreadPool.RegisterWaitForSingleObject(
                result.get_AsyncWaitHandle(), 
                new WaitOrTimerCallback(TimeoutCallback), 
                myHttpWebRequest, defaultTimeout, true);

            // The response came in the allowed time. 
            // The work processing will happen in the callback function.
            allDone.WaitOne();

            // Release the HttpWebResponse resource.
            myRequestState.response.Close();
        }
        catch(WebException e) {
            Console.WriteLine("\nMain Exception raised!");
            Console.WriteLine("\nMessage:{0}", e.get_Message());
            Console.WriteLine("\nStatus:{0}", e.get_Status());
            Console.WriteLine("Press any key to continue..........");
        }
        catch(System.Exception  e) {
            Console.WriteLine("\nMain Exception raised!");
            Console.WriteLine("Source :{0} ", e.get_Source());
            Console.WriteLine("Message :{0} ", e.get_Message());
            Console.WriteLine("Press any key to continue..........");
            Console.Read();
        }
    } //main
   
    private static void RespCallback(IAsyncResult asynchronousResult)
    {
        try {
            // State of request is asynchronous.
            RequestState myRequestState = 
                ((RequestState)(asynchronousResult.get_AsyncState()));
            HttpWebRequest myHttpWebRequest = myRequestState.request;
            myRequestState.response =
                ((HttpWebResponse)(myHttpWebRequest.EndGetResponse(
                    asynchronousResult)));

            // Read the response into a Stream object.
            Stream responseStream = 
                myRequestState.response.GetResponseStream();
            myRequestState.streamResponse = responseStream;

            // Begin the Reading of the contents of the HTML page and 
            // print it to the console.
            IAsyncResult asynchronousInputRead = 
                responseStream.BeginRead(myRequestState.bufferRead, 0, 
                BUFFER_SIZE, new AsyncCallback(ReadCallBack), myRequestState);
            return;
        }
        catch(WebException e) {
            Console.WriteLine("\nRespCallback Exception raised!");
            Console.WriteLine("\nMessage:{0}", e.get_Message());
            Console.WriteLine("\nStatus:{0}", e.get_Status());
        }
        allDone.Set();
    } //RespCallback
   
    private static void ReadCallBack(IAsyncResult asyncResult) 
    {
        try {
            RequestState myRequestState = 
                ((RequestState)(asyncResult.get_AsyncState()));
            Stream responseStream = myRequestState.streamResponse;
            int read = responseStream.EndRead(asyncResult);
            // Read the HTML page and then print it to the console.
            if ( read > 0  ) {
                myRequestState.requestData.Append(
                    Encoding.get_ASCII().GetString(
                    myRequestState.bufferRead, 0, read));
                IAsyncResult asynchronousResult = 
                    responseStream.BeginRead(myRequestState.bufferRead, 0, 
                    BUFFER_SIZE, new AsyncCallback(ReadCallBack), 
                    myRequestState);
                return ;
            }
            else {
                Console.WriteLine("\nThe contents of the Html page are : ");
                if ( myRequestState.requestData.get_Length() > 1  ) {
                    String stringContent;
                    stringContent = myRequestState.requestData.ToString();
                    Console.WriteLine(stringContent);
                }
                Console.WriteLine("Press any key to continue..........");
                Console.ReadLine();
                responseStream.Close();
            }
        } 
        catch(WebException e) {
            Console.WriteLine("\nReadCallBack Exception raised!");
            Console.WriteLine("\nMessage:{0}", e.get_Message());
            Console.WriteLine("\nStatus:{0}", e.get_Status());
        }
        allDone.Set();
    } //ReadCallBack