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Socket establishes connection but unable to pass command through stream

Posted on 2006-06-21
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Last Modified: 2010-03-31
Learning Java so please bear with me..
I am trying this exercise (not school homework) where
I am passing URL String eg http:/www.myurl.com/mydir/myfile.html to the class. Constructor dissects into host  using getHost() and file name getFile().
Then there is a method which tries following:
1)Establish connection at port 80 with host
2)Connect OutputStreamWriter to Socket output Stream
3)Use OutputStreamWriter write method to pass string GET /mydir/myfile.html HTTP1.0
4)Similarly connect InputStreamReader to Socket input stream , BufferReader to InputStreamReader. Try to dump BufferReader to a file.

Compiles without error. But when run nothing happens. Tried to see the behevour of client using Ethereal. 3 way TCP hand shake happens but nothing happens beyond that point.  Not sure what went wrong with coding please help

Code of the method only
 public void myGetClient(){
               Socket mySocket=null;
               Writer command=null;
               Reader fetch=null;
               BufferedReader storeFetch=null;
               FileWriter fileOut=null;
               // Generating HTTP Command //
               StringBuffer cmdText=new StringBuffer();
               cmdText=cmdText.append("GET ");
               cmdText=cmdText.append(file);
               cmdText=cmdText.append(" HTTP/1.0/r/n");
               cmdText.toString();
               String cmdteXt=cmdText.toString();
               System.out.println(cmdteXt);
               // Command Generated //

               // Establish TCP/IP  Connection //
               try {
                mySocket=new Socket(host,port);
               } catch (UnknownHostException e) {
                       // TODO Auto-generated catch block
                       e.printStackTrace();
               } catch (IOException e) {
                       // TODO Auto-generated catch block
                       e.printStackTrace();
               }

               // Send Command to TCP/IP stream //
               try {
                       command=new OutputStreamWriter(mySocket.getOutputStream(),"latin1");  //Connecting to TCP/IP Stream //
               } catch (UnsupportedEncodingException e) {
                       // TODO Auto-generated catch block
                       e.printStackTrace();
               } catch (IOException e) {
                       // TODO Auto-generated catch block
                       e.printStackTrace();
               }
               try {
                       command.write(cmdteXt); // Dumping into TCP/IP stream //
                       command.flush();
               } catch (IOException e1) {
                       // TODO Auto-generated catch block
                       e1.printStackTrace();
               }
               // Command Sent. Hopefully !!! //

               // See what is there on other side //
                   try {
                               fetch=new InputStreamReader(mySocket.getInputStream(), "latin1");
// Connecting to TCP/IP Stream //
                       } catch (UnsupportedEncodingException e) {
                               // TODO Auto-generated catch block
                               e.printStackTrace();
                       } catch (IOException e) {
                               // TODO Auto-generated catch block
                               e.printStackTrace();
                       }
                         storeFetch=new BufferedReader(fetch); /

                         try {
                               fileOut=new FileWriter("Download.html");      // Open File
                       } catch (IOException e1) {
                               // TODO Auto-generated catch block
                               e1.printStackTrace();
                       }

                         try {
                                 String input;
                               while(( input=storeFetch.readLine())!=null){
                                       fileOut.write(storeFetch.readLine());
                                       System.out.println(input);


                                 }
                       } catch (IOException e) {
                               // TODO Auto-generated catch block
                               e.printStackTrace();
                       }
}
0
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Question by:sanjoybasu
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15 Comments
 
LVL 35

Expert Comment

by:girionis
ID: 16949001
Where does it get stuck? Do you have an acitve connection? Are you behind a firewall?
0
 

Author Comment

by:sanjoybasu
ID: 16949016
No I am not behind firewall. Once TCP session establishes nothing happens.
0
 
LVL 35

Expert Comment

by:girionis
ID: 16949061
Maybe you need to send more data, like Content-length etc. Have a look how it is done here: http://javaalmanac.com/egs/java.net/PostSocket.html with a POST request. Also, you do not need several try... catch blocks of code, all can be done within one :)
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Author Comment

by:sanjoybasu
ID: 16949114
girionis  I disagree with your earlier comment of not sending more data. If that was the case I should see HTTP request to server atleast then may be some kind of HTTP 4xx client error in Ethereal. I dont see any HTTP request sent to server. Also when I access the same URL using standard browser it send exactly same GET /mydir/myfile.html HTTP1.0 as I am trying to send  and server acks with HTTP code 200.
0
 
LVL 86

Expert Comment

by:CEHJ
ID: 16949142
Try

cmdText=cmdText.append(" HTTP/1.0/r/n/r/n");

If that doesn't work, please post the value of that StringBuffer
0
 
LVL 86

Accepted Solution

by:
CEHJ earned 672 total points
ID: 16949147
Correction:

cmdText=cmdText.append(" HTTP/1.0\r\n\r\n");
0
 
LVL 35

Assisted Solution

by:girionis
girionis earned 664 total points
ID: 16949154
Ok, are you sure you are connecting to the right host? What are the "host" and "port" variables?
0
 
LVL 35

Expert Comment

by:girionis
ID: 16949166
> cmdText=cmdText.append(" HTTP/1.0\r\n\r\n");

Nice catch.
0
 
LVL 30

Expert Comment

by:Mayank S
ID: 16949302
Why not try URLConnection?
0
 
LVL 30

Assisted Solution

by:Mayank S
Mayank S earned 664 total points
ID: 16949310
0
 
LVL 4

Expert Comment

by:Yagantappa
ID: 16950467
For http requests, you need to send "Content-length". Without it, requests will not be complete.
0
 
LVL 30

Expert Comment

by:Mayank S
ID: 16950625
I doubt you need to do that for requests. It is only for response.
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