Overview

For this lab, you will modify the sample JAVA sockets client to add function. We are essentially programming the function we performed manually with telnet in the homework exercise. In particular, we want to:

• Prompt the user for the name of the host to which we want to connect. Connect to this host using the port for HTTP.
• Then prompt the user for a URL on that host (e.g. /erodd/ttest.htm) Send a proper HTTP GET command using this URL.
• Use a loop to get lines from the host to get all the HTTP headers and some HTML.

JAVA review

Remember to compile and run JAVA (WINDOWS or LINUX):

• In LINUX, remember to do the "mnet logon" command to get the hdrive and tdrive.
• Create a program

  sockiii.java (iii = your initials)
  

  using "vi" on LINUX or Notepad or other editor on Windows.
• Compile with:

  javac sockiii.java
  

• Run with:

  java sockiii
  

• Copy the result to the instructor drive:

  WINDOWS: COPY sockiii.java T:\ERODD\STUDENTS
  
  LINUX in TS111: tot sockiii.java
  

Getting the starting program

The program sample to start with is in the file:

WINDOWS: T:\ERODD\TCPCLI.JAVA

LINUX: /home/square/tdrive/erodd/tcpcli.java

Things to change

• The class name on the JAVA class statement -- change to "sockiii".
• Add the prompt for the host name (for example, you could then test with www.malone.edu).
• Change the creation of the socket to use the host name typed in instead of "localhost" and to use the correct port number for HTTP.
• Change the prompt "Enter a string to send to the server" to a prompt for a URL.
• Construct a proper HTTP get (don't forget the "HTTP/1.1" part!!)
• Send the GET command. You need to add an extra "\n" to put an extra newline on the end. The "println()" method puts in one newline, but you need two to tell the server that the HTTP is ended.
• Read from the socket in a loop. Remember the JAVA for loop:

     for (int i=0; i<10; i++)
     {
        // read the socket
        // display the results
     }
  

  Read enough lines (the above example would be 10) to read the HTTP header and some HTML. If you try to read too many lines, you will just get a lot of "null" results.

To Turn In

Copy your program to the instructor tdrive.

Printed copy of your program with a handwritten notation of what host and URL you tested with.
Remember on LINUX print with:

   a2ps sockiii.java

Extra Challenge

The maximum grade without this extra is 95%. The maximum grade with this extra challenge is 120.

The extra challenge is: Write logic to read exactly as much data as the server sends. Hint: There is information in the HTTP header you need. Look at an Ethereal trace to find it.