Metacat

/**

 *  '$RCSfile$'

 *    Purpose: Used for Java applet/application communication

 *             with servlet. Based on code given in the book

 *             "Java Servlet Programming" by Hunter & crawford

 *  Copyright: 2000 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Dan Higgins modified for metacat by Chad Berkley

 *    Release: @release@

 *

 *   '$Author: jones $'

 *     '$Date: 2001-01-18 11:52:00 -0800 (Thu, 18 Jan 2001) $'

 * '$Revision: 669 $'

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.metacat;

import java.io.*;

import java.net.*;

import java.util.*;

/**

 * Send a message to an HTTP server using either a GET or POST operation

 */

public class HttpMessage {

    public String contype;

    URL servlet = null;

    String argString = null;

    static String cookie = null;

    public HttpMessage(URL servlet) {

        this.servlet = servlet;

    }

    /**

     * return the cookie that this message object contains

     */

    public static String getCookie()

    {

      return cookie;

    }

    /**

     * Performs a GET request to the previously given servlet

     * with no query string

    */

    public InputStream sendGetMessage() throws IOException {

        return sendGetMessage(null);

    }

    /**

     * Performs a GET request to the previously given servlet

     *Builds a query string from the supplied Properties list.

     */

    public InputStream sendGetMessage(Properties args) throws IOException {

        argString = ""; //default

        if (args != null) {

            argString = "?" + toEncodedString(args);

        }

        URL url = new URL(servlet.toExternalForm() + argString);

        // turn off caching

        URLConnection con = url.openConnection();

        con.setUseCaches(false);

        contype = con.getContentType();

        return con.getInputStream();

    }

    /**

     * Performs a POST request to the previously given servlet

     * with no query string

     */

    public InputStream sendPostMessage() throws IOException {

        return sendPostMessage(null);

    }

    /**

     * Builds post data from the supplied properties list

     */

    public InputStream sendPostMessage(Properties args) throws IOException {

        argString = ""; //default

        if (args != null) {

            argString = toEncodedString(args); 

        }

        URLConnection con = servlet.openConnection();

        if (cookie!=null) {

            int k = cookie.indexOf(";");

            if (k>0) {

                cookie = cookie.substring(0, k);

            }

            //System.out.println("Cookie = " + cookie);

            con.setRequestProperty("Cookie", cookie); 

            con.setRequestProperty("User-Agent", "MORPHO");  // add 10/26/00 by DFH so Metacat can determine where request come from

        }

        //prepare for both input and output

        con.setDoInput(true);

        con.setDoOutput(true);

        //turn off caching

        con.setUseCaches(false);

        //work around a Netscape bug

        //con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

        //Write the arguments as post data

        DataOutputStream out = new DataOutputStream(con.getOutputStream());

        out.writeBytes(argString);

        out.flush();

        contype = con.getContentType();

        String temp = con.getHeaderField("Set-Cookie");

        if (temp!=null) {

            cookie = temp;

        }

        //System.out.println(cookie);

        out.close();

        return con.getInputStream();

    }

    /**

     * Returns the urls argument strings

     */

    public String getArgString() {

        String argString1 = argString;

        if (!argString1.startsWith("?")) {

            argString1 = "?"+argString1;}

        return argString1;

    }

    /**

     * Converts a Properties list to a URL-encoded query string

     */

    private String toEncodedString(Properties args) {

        StringBuffer buf = new StringBuffer();

        Enumeration names = args.propertyNames();

        while (names.hasMoreElements()) {

            String name = (String)names.nextElement();

            String value = args.getProperty(name);

            buf.append(URLEncoder.encode(name) + "=" + URLEncoder.encode(value));

            if (names.hasMoreElements()) buf.append("&");

        }

        return buf.toString();

    }

}