Solved

Socket establishes connection but unable to pass command through stream

Posted on 2006-06-21
15
270 Views
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
Comment
Question by:sanjoybasu
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 3
  • 2
  • +2
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 :)
0
What Is Transaction Monitoring and who needs it?

Synthetic Transaction Monitoring that you need for the day to day, which ensures your business website keeps running optimally, and that there is no downtime to impact your customer experience.

 

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 168 total points
ID: 16949147
Correction:

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

Assisted Solution

by:girionis
girionis earned 166 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 166 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.
0

Featured Post

Online Training Solution

Drastically shorten your training time with WalkMe's advanced online training solution that Guides your trainees to action. Forget about retraining and skyrocket knowledge retention rates.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Java Flight Recorder and Java Mission Control together create a complete tool chain to continuously collect low level and detailed runtime information enabling after-the-fact incident analysis. Java Flight Recorder is a profiling and event collectio…
Introduction This article is the second of three articles that explain why and how the Experts Exchange QA Team does test automation for our web site. This article covers the basic installation and configuration of the test automation tools used by…
Viewers learn about the “while” loop and how to utilize it correctly in Java. Additionally, viewers begin exploring how to include conditional statements within a while loop and avoid an endless loop. Define While Loop: Basic Example: Explanatio…
Viewers will learn how to properly install Eclipse with the necessary JDK, and will take a look at an introductory Java program. Download Eclipse installation zip file: Extract files from zip file: Download and install JDK 8: Open Eclipse and …

691 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question