467,121 Members | 1,337 Online
Bytes | Developer Community
Ask Question

Home New Posts Topics Members FAQ

Post your question to a community of 467,121 developers. It's quick & easy.

Read contents of a web page

Hi All,

I am trying to read the contents of a page through its URL.

My code snippet is as follows:
public void mtdGetPageDataHWR()
{
HttpWebRequest objRequ =
(HttpWebRequest)WebRequest.Create("http://www.microsoft.com");
HttpWebResponse objResp = (HttpWebResponse)objRequ.GetResponse();
string strVersion = objResp.ProtocolVersion.ToString();
StreamReader objRd = new StreamReader(objResp.GetResponseStream());
string strRd = objRd.ReadLine();
while(strRd!=null)
{
Response.Write(strRd);
strRd = objRd.ReadLine();
}
}

Is there any other way to achieve this which could be more efficient or
faster than this.

Any help on this would be very handy

Thanks,

Kuldeep
Oct 24 '06 #1
  • viewed: 3757
Share:
4 Replies
You should use myHttpWebRequest.BeginGetResponse to do it asynchronous.
and retrieve the response from EndGetResponse.

Here is an example from MSDN on how to do that.
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.G etString(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();

}

Kuldeep wrote:
Hi All,

I am trying to read the contents of a page through its URL.

My code snippet is as follows:
public void mtdGetPageDataHWR()
{
HttpWebRequest objRequ =
(HttpWebRequest)WebRequest.Create("http://www.microsoft.com");
HttpWebResponse objResp = (HttpWebResponse)objRequ.GetResponse();
string strVersion = objResp.ProtocolVersion.ToString();
StreamReader objRd = new StreamReader(objResp.GetResponseStream());
string strRd = objRd.ReadLine();
while(strRd!=null)
{
Response.Write(strRd);
strRd = objRd.ReadLine();
}
}

Is there any other way to achieve this which could be more efficient or
faster than this.

Any help on this would be very handy

Thanks,

Kuldeep

Oct 24 '06 #2
Hi Sun,

Is there a method which could be as fast as a "Ctrl+F" on
a web page to achieve the same?
Or something that we could control through Javascript or any scripting
language for that matter?
Thanks for the response
Kuldeep
"Jianwei Sun" <js***********@gmail.comwrote in message
news:uI**************@TK2MSFTNGP05.phx.gbl...
You should use myHttpWebRequest.BeginGetResponse to do it asynchronous.
and retrieve the response from EndGetResponse.

Here is an example from MSDN on how to do that.
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.G etString(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();

}

Kuldeep wrote:
>Hi All,

I am trying to read the contents of a page through its URL.

My code snippet is as follows:
public void mtdGetPageDataHWR()
{
HttpWebRequest objRequ =
(HttpWebRequest)WebRequest.Create("http://www.microsoft.com");
HttpWebResponse objResp = (HttpWebResponse)objRequ.GetResponse();
string strVersion = objResp.ProtocolVersion.ToString();
StreamReader objRd = new StreamReader(objResp.GetResponseStream());
string strRd = objRd.ReadLine();
while(strRd!=null)
{
Response.Write(strRd);
strRd = objRd.ReadLine();
}
}

Is there any other way to achieve this which could be more efficient or
faster than this.

Any help on this would be very handy

Thanks,

Kuldeep
Oct 24 '06 #3
If I understand correctly, you are looking for some client-side
functionalities, then this is really a wrong group to post this question.

Kuldeep wrote:
Hi Sun,

Is there a method which could be as fast as a "Ctrl+F" on
a web page to achieve the same?
Or something that we could control through Javascript or any scripting
language for that matter?
Thanks for the response
Kuldeep
"Jianwei Sun" <js***********@gmail.comwrote in message
news:uI**************@TK2MSFTNGP05.phx.gbl...
>You should use myHttpWebRequest.BeginGetResponse to do it asynchronous.
and retrieve the response from EndGetResponse.

Here is an example from MSDN on how to do that.
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(asynchronousResul t);

// 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.BufferRea d, 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();

}

Kuldeep wrote:
>>Hi All,

I am trying to read the contents of a page through its URL.

My code snippet is as follows:
public void mtdGetPageDataHWR()
{
HttpWebRequest objRequ =
(HttpWebRequest)WebRequest.Create("http://www.microsoft.com");
HttpWebResponse objResp = (HttpWebResponse)objRequ.GetResponse();
string strVersion = objResp.ProtocolVersion.ToString();
StreamReader objRd = new StreamReader(objResp.GetResponseStream());
string strRd = objRd.ReadLine();
while(strRd!=null)
{
Response.Write(strRd);
strRd = objRd.ReadLine();
}
}

Is there any other way to achieve this which could be more efficient or
faster than this.

Any help on this would be very handy

Thanks,

Kuldeep
Oct 24 '06 #4
Hi,

A very simple way to download data over web is using a WebClient

System.Net.WebClient client = new System.Net.WebClient();
byte[] data = client.DownloadData("http://www.microsoft.com");
string html = System.Text.Encoding.UTF8.GetString(data);

However, using a webclient, you have little control of the transfer.

--
Happy Coding!
Morten Wennevik [C# MVP]
Oct 24 '06 #5

This discussion thread is closed

Replies have been disabled for this discussion.

Similar topics

4 posts views Thread by ESPN Lover | last post: by
3 posts views Thread by dave_nul@hotmail.com | last post: by
9 posts views Thread by =?Utf-8?B?TWlrZQ==?= | last post: by
28 posts views Thread by tlpell@gmail.com | last post: by
By using this site, you agree to our Privacy Policy and Terms of Use.