import java.net.*;
import java.io.*;

/**
  * CGI interface allows a java program to send POST-style 
  * messages to a CGI on a server.
  * @author J. Dalbey
  * @version 2/28/06
  * Here is an example perl CGI:
  * <pre>
#!/usr/bin/perl
# this is a perl CGI that will accept a POST request
# and append the info to a text file.
 
open(OUT, ">> LobbyStatus.txt");
print "content-type: text/plain\n\n";
 
# write the POST data to the file
while (<>) {
    print OUT $_;
    print OUT "\n";
}
close (OUT);
 
#Echo an acknowledgement to the sender
print "OK";
exit 0;
  * </pre>
  *
  */
public class CGIinterface
{
    /**  The domain to connect to: e.g., www.calpoly.edu */
    private String domain;  
    /** The path to the CGI (relative to the domain) */
    private String cgiName;    

    /**
     * Construct a CGI interface.
     * @param domain the domain where the server resides, e.g., <code>www.csc.calpoly.edu</code>
     * @param cgiName the path to the CGI (relative to the domain), e.g., <code>/~jstudent/mycgi.pl</code>
     */
    public CGIinterface (String domain, String cgiName)
    {
        this.domain = domain;
        this.cgiName = cgiName;
    }

    /** Send a message to the CGI
     * @param message A string to be sent to the cgi containing POST data
     */
    public void sendPostData(String message) 
    {
        /*
        Open the URL using openConnection(). 
        As this is using a CGI POST to send the data 
        (as opposed to a GET in which the data would be appended to the end of the URL i.e. http://www.yourdomain.com/cgi-bin/writeit?myinfo), 
        we are defining the Content-type to be text/plain. 
        */
        URL url;
        URLConnection con = null;

        try
        {
            url = new URL("http",domain,cgiName);
            con = url.openConnection();
        } 
        catch (MalformedURLException ex){ex.printStackTrace();}
        catch (IOException ex) {ex.printStackTrace();}

        // Prepare the connection
        con.setDoOutput(true);
        con.setDoInput(true);
        con.setUseCaches(false);
        con.setRequestProperty("Content-type", "text/plain");
        con.setRequestProperty("Content-length", message.length()+"");

        // Send the message over the connection
        try
        {
        PrintStream out = new PrintStream(con.getOutputStream());
        out.print(message);
        out.flush();
        out.close();

        // Read and swallow anything the server sends back to us.
        DataInputStream in =
            new DataInputStream(con.getInputStream());
        String s;
        while ((s = in.readLine()) != null)
        {
            //System.out.println(s);
        }
        in.close();
        }
        catch (IOException ex) {ex.printStackTrace();}

    }

    /** a local main for unit testing */
    public static void main(String args[]) 
    {
        String lobby_info = "Sun Feb 26 15:55:40 PST 2006 129.65.111.22   Need 3 players";
        CGIinterface myCGI = new CGIinterface("www.csc.calpoly.edu",
                          "/~jdalbey/Public/LobbyUpdate.pl");
        myCGI.sendPostData(lobby_info);
    }

}