Solved

Error: "Unable to connect to the remote server" when using GetResponse or EndGetResponse

Posted on 2004-03-29
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Last Modified: 2010-08-05
Hi,

the title says it all really - I'm certain the code's right, after scouring the internet for hours trying to solve this, but I can't get away from the error.
I'm basically trying to save a webpage to file, given a url.
So is it something to do with my internet setup or firewall?
Incidentally, when I try to add a web reference in visual studio, it gives the same error but still brings the webpage up.

Any ideas? Cheers all.
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Question by:shifty_mc
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9 Comments
 
LVL 12

Expert Comment

by:dfiala13
ID: 10710500
Post your code. It could be a firewall issue, but if you are accessing the Internet otherwise it is unlikely.
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Author Comment

by:shifty_mc
ID: 10710603
ok...

public Browser()
{
      Uri url = new Uri("http://www.radiotimes.com/tv/now.html");
      HttpWebRequest wr = (HttpWebRequest) WebRequest.Create(url);            
      AsyncCallback a = new AsyncCallback(OnComplete);
      IAsyncResult r = (IAsyncResult) wr.BeginGetResponse(a,wr);
}

static void OnComplete(IAsyncResult ar)
{
      
      HttpWebRequest r = (HttpWebRequest) ar.AsyncState;
      HttpWebResponse re = (HttpWebResponse) r.EndGetResponse(ar);                        
      Stream str = re.GetResponseStream();
      Byte[] inBuf = new Byte[500000];
                int bytesToRead = (int) inBuf.Length;
      int bytesRead = 0;
      while (bytesToRead > 0)
      {
            int n = str.Read(inBuf, bytesRead,bytesToRead);
                      if (n==0)
            break;
            bytesRead += n;
            bytesToRead -= n;
      }
      FileStream fstr = new FileStream("C:\\webpagetest.html", FileMode.Create,FileAccess.Write);
      fstr.Write(inBuf, 0, bytesRead);
      str.Close();
      fstr.Close();            
}

The error occurs in the line
HttpWebResponse re = (HttpWebResponse) r.EndGetResponse(ar);
I've also tried it synchronously, with GetResponse, and get the same error.
Thanks.
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LVL 12

Expert Comment

by:dfiala13
ID: 10710697
I think the problem is that you are never starting the communication.  Here's a snippet I wrote for a scraper.  It's snychronous and it uses a string URL as opposed to creating a Uri object.

Try this and see if it works (works for me), then we will at least know if it is a code problem or not.

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(sURL);
req.KeepAlive = false;
HttpWebResponse res = (HttpWebResponse)req.GetResponse();
StreamReader sr = new StreamReader(res.GetResponseStream(),true);
string s = sr.ReadToEnd();
res.Close();
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Author Comment

by:shifty_mc
ID: 10710761
yeah, still get the error in
HttpWebResponse res = (HttpWebResponse)req.GetResponse();
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Author Comment

by:shifty_mc
ID: 10710823
Ahh, I've got it - I was connecting to the internet through a proxy which was causing the problem.
When I turned that off it worked fine.
But how would I use this code when working with proxies and so on - ideally I'd be able to check the connection on a user's computer and adjust the connection appropriately?
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LVL 12

Expert Comment

by:dfiala13
ID: 10710876
Ah, a proxy!  There is a class for working with that and a little code to tell your app to use a proxy.

http://support.microsoft.com/default.aspx?scid=kb;en-us;307023
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LVL 12

Accepted Solution

by:
dfiala13 earned 250 total points
ID: 10710885
You can add a test function that tries to connect to a well known and ususally up URL (http://www.microsoft.com).  If it fails you can switch over to the proxy code and possibly prompt the user for proxy info.
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Author Comment

by:shifty_mc
ID: 10710931
ok, I'll give it a go,
thanks for your help.
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LVL 12

Expert Comment

by:dfiala13
ID: 10710957
You're welcome.  Glad you got it working.
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