source: main/trunk/gli/src/org/greenstone/gatherer/greenstone/LocalLibraryServer.java@ 22661

/**
 *############################################################################
 * A component of the Greenstone Librarian Interface, part of the Greenstone
 * digital library suite from the New Zealand Digital Library Project at the
 * University of Waikato, New Zealand.
 *
 * Author: Michael Dewsnip, NZDL Project, University of Waikato, NZ
 *
 * Copyright (C) 2004 New Zealand Digital Library Project
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *############################################################################
 */

package org.greenstone.gatherer.greenstone;


import java.io.*;
import java.lang.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import org.greenstone.gatherer.Configuration;
import org.greenstone.gatherer.DebugStream;
import org.greenstone.gatherer.Dictionary;
import org.greenstone.gatherer.Gatherer;
import org.greenstone.gatherer.util.PortFinder;
import org.greenstone.gatherer.util.Utility;


public class LocalLibraryServer
{
    static final private int WAITING_TIME = 20; // number of seconds to wait for the server to start and stop

    static final private String ADD_COMMAND = "?a=config&cmd=add-collection&c=";
    static final private String RELEASE_COMMAND = "?a=config&cmd=release-collection&c=";
    static final private String QUIT_COMMAND = "?a=config&cmd=kill";

    static private LLSSiteConfig llssite_cfg_file = null;
    static private File local_library_server_file = null;

    static private boolean running = false;
    static private String ID = "greenstone-server"; // a sort of process ID

    // Need to use sockets to tell the server program to terminate when on Linux
    // The socket port number that we will use to communicate the termination
    static private int port;
    static private Socket clientSocket = null;
    static private Writer clientSocketWriter = null;

    // The server is persistent if it does not have to reload all the values
    // over and over again each time. Tomcat is persistent and fastcgi is too,
    // but the Apache webserver is not persistent by default.
    // Change the initialisation of this value depending on whether fastcgi is 
    // on. At the moment, this does not apply to the Apache local library server.
    static private boolean isPersistentServer = false;

    static public void addCollection(String collection_name)
    {
    if (isPersistentServer) {
        config(ADD_COMMAND + collection_name);
    }
    }


    // Used to send messages to the local library
    static private void config(String command)
    {
    if (!isPersistentServer) {
        return;
    }
    if (Configuration.library_url == null) {
        System.err.println("Error: Trying to configure local library with null Configuration.library_url!");
        return;
    }

    try {
        URL url = new URL(Configuration.library_url.toString() + command);
        HttpURLConnection library_connection = (HttpURLConnection) url.openConnection();

        // It's very important that we read the output of the command
        // This ensures that the command has actually finished
        // (The response code is returned immediately)
        InputStream library_is = library_connection.getInputStream();
        BufferedReader library_in = new BufferedReader(new InputStreamReader(library_is, "UTF-8"));
        String library_output_line = library_in.readLine();
        while (library_output_line != null) {
        DebugStream.println("Local library server output: " + library_output_line);
        library_output_line = library_in.readLine();
        }
        library_in.close();

        int response_code = library_connection.getResponseCode();
        if (response_code >= HttpURLConnection.HTTP_OK && response_code < HttpURLConnection.HTTP_MULT_CHOICE) {
        DebugStream.println("200 - Complete.");
        }
        else {
        DebugStream.println("404 - Failed.");
        }
    }
    catch (Exception exception) {
        DebugStream.printStackTrace(exception);
    }
    }

    // Used to send messages to the local library server wrapper to the Apache web server (server.jar)
    static private boolean sendMessageToServer(String message) {
    if(isPersistentServer) {
        return false;
    }
    
    if(port == -1) {
        return false;
    }
        
    try {
        if(clientSocket == null) {
        clientSocket = new Socket("localhost", port);
        }
        if(clientSocketWriter == null) {
        clientSocketWriter = new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()));
        }
        clientSocketWriter.write(message);
        clientSocketWriter.flush();
        
    } catch (Exception e) {
        System.err.println("An exception occurred when trying to send the message: " + message 
                   + "\nto the LocalLibraryServer.\n" + e);
        return false;
    } 
    return true;
    }

    static public boolean isRunning()
    {
    if (!running) return false; // if the url is pending, then running would also be false (server not started up yet)

    llssite_cfg_file.load(true);
    String url = llssite_cfg_file.getURL();
    if (url == null) return false;
    
    // Called by Gatherer to check whether we need to stop the server.
    // if the url is pending, then the GSI hasn't started the server up yet
    // Already covered in !running
    //if (url.equals(LLSSiteConfig.URL_PENDING)) return false;

    return true;
    }


    static public void releaseCollection(String collection_name)
    {
    if (isPersistentServer) {
        config(RELEASE_COMMAND + collection_name);
    }
    }

    static public boolean start(String gsdl_path, String local_library_server_file_path)
    {
    // Check the local library server file (server.exe or gs2-server.sh) exists
    if(local_library_server_file_path == null) {
        return false;
    }
    local_library_server_file = new File(local_library_server_file_path);
    if (local_library_server_file.exists()) {
        if(local_library_server_file.getName().equals("server.exe")) {
        isPersistentServer = true;
        } // else it may be gs2-web-server.bat
    }
    else { // local_library_server_file does not exist
        DebugStream.println("No local library at given file path.");

        if(Utility.isWindows()) { // test for server.exe and gs2-web-server.bat
        local_library_server_file = new File(gsdl_path + "server.exe");
        if (local_library_server_file.exists()) {
            isPersistentServer = true;
        } else {
            local_library_server_file = new File(gsdl_path + "gs2-web-server.bat");
            if (!local_library_server_file.exists()) {
            DebugStream.println("No local library at all.");
            return false;
            }
        }       
        } else { // linux
        local_library_server_file = new File(gsdl_path + "gs2-server.sh");
        if (!local_library_server_file.exists()) {
            DebugStream.println("No local library at all.");
            return false;
        }
        }
    }   

    if(!isPersistentServer) {
        // In the case of the Local Library Server on Linux or on Win where there's no server.exe, do an extra test:
        // If GS2 was not configured with --enable-apache-httpd, then there is no apache webserver folder,
        // even though the gs2-server.sh file would still be there. That means if the folder is absent 
        // we still have no local library server.

        File localServerFolder = new File(gsdl_path, "apache-httpd");
        if (!localServerFolder.exists() && !localServerFolder.isDirectory()) {
        DebugStream.println("The web server does not exist at " 
                + localServerFolder.getAbsolutePath() + "\nNo local library at all. Trying web library");
        return false;
        } // else apache-httpd folder exists
    }

    llssite_cfg_file = new LLSSiteConfig(local_library_server_file);
    if(!llssite_cfg_file.isConfigFileSet()) {
        return false;
    }

    // from now on return true: we're in local_library_mode (even if the server is not running)

    
    // If the user launched the GSI independent of GLI, but user has not pressed
    // Enter Library yet, then we will obtain the previewURL later.
    if(LocalLibraryServer.isURLPending()) {
        // running is still false when the URL is pending because only GSI is running, not the server
        return true;
    } else if(llssite_cfg_file.isIndependentGSI()) {
        // there is a url, it's not pending, and it is llssite.cfg: meaning GSI has started up
        running = true;
        return true;    
    }

    // Spawn local library server process
    final String QUOTES = Utility.isWindows() ? "\"" : ""; // need to embed path in quotes on Windows for spaces (interferes on Linux)
    String local_library_server_command = QUOTES+local_library_server_file.getAbsolutePath()+QUOTES + getExtraLaunchArguments(llssite_cfg_file);
    if(Utility.isWindows() && !isPersistentServer) { // launching gs2-web-server.bat (Windows) needs cmd start
        local_library_server_command = "cmd.exe /c start \"GSI\" " + local_library_server_command;
    }

    // Check if the server is already running
    String url = llssite_cfg_file.getURL();
    if (url != null) {
        // If it is already running then set the Greenstone web server address and we're done
        // E.g. if previously GLI was not properly shut down, the URL property (signifying 
        // the server is still running) would still be in the glisite_cfg file.
        try {
        Configuration.library_url = new URL(url);
        running = true;

        // Run the server interface
        Gatherer.spawnApplication(local_library_server_command, ID);
        return true;
        }
        catch (MalformedURLException exception) {
        DebugStream.printStackTrace(exception);
        }
    }   

    // Configure the server for immediate entry
    //llssite_cfg_file.set();

    // Spawn local library server process
    Gatherer.spawnApplication(local_library_server_command, ID);
    
    // Wait until program has started
    try {
        //System.err.println("**** testing server...");
        testServerRunning(); // will set running = true when the server is up and running successfully
        //System.err.println("**** Is server running: " + running);
    } catch (IOException bad_url_connection) {
        try {
        // If this fails then we try changing the url to be localhost
        Configuration.library_url = new URL(llssite_cfg_file.getLocalHostURL());
        DebugStream.println("Try connecting to server on local host: '" + Configuration.library_url + "'");
        URLConnection connection = Configuration.library_url.openConnection();
        connection.getContent();
        running = true;
        
        } catch (IOException worse_url_connection) {
        DebugStream.println("Can't connect to server on either address.");
        Configuration.library_url = null;
        running = false;
        }
    }

    return true;
    }

    /** Call this when the collect directory has changed. Only works when using 
     * the web server launched by GLI. */
    static public void reconfigure() {
    if(isPersistentServer) {
        System.err.println("***** Reconfigure is not yet implemented for server.exe");
        return;
    }

    // can't control the GSI/server if it was launched independent of GLI
    if(llssite_cfg_file.isIndependentGSI()) {
        JOptionPane.showMessageDialog(Gatherer.g_man, Dictionary.get("Server.Reconfigure"), Dictionary.get("General.Reconfigure"), JOptionPane.INFORMATION_MESSAGE);
        return;
    }

    // someone may have closed the web server
    if(checkServerRunning()) { // need a server to be running in order for us to send a reconfigure message to it
        return; // it has reconfigured and restarted the server
    }

    // If it was already running, tell the server a reconfigure is required on next restart
    // and then restart
    if(running && sendMessageToServer("RECONFIGURE\n")) {
        // restart
        if(running) {
        running = false;

        if(sendMessageToServer("RESTART\n")) { //if(sendMessageToServer("RECONFIGURE\n")) {
            // wait for the server to update the URL in the gli config file
            llssite_cfg_file.setLastModified();
            
            int attempt_count = 0;
            while (!llssite_cfg_file.isModified()) {
            new OneSecondWait();  // Wait one second (give or take)
            attempt_count++;
            
            // After waiting for the specified time, ask the user whether they want to wait for that long again
            if (attempt_count == WAITING_TIME) {
                break; // can't be waiting forever, we'll be waiting again below
            }
            }           

            try {       
            testServerRunning(); // will set running = true when the server is up and running successfully
            } catch (IOException bad_url_connection) {
            try {
                // If this fails then we try changing the url to be localhost
                Configuration.library_url = new URL(llssite_cfg_file.getLocalHostURL());
                DebugStream.println("Try connecting to server on local host: '" + Configuration.library_url + "'");
                URLConnection connection = Configuration.library_url.openConnection();
                connection.getContent();
                running = true;
                
            } catch (IOException worse_url_connection) {
                DebugStream.println("Can't connect to server on either address.");
                Configuration.library_url = null;
                running = false;
            }
            }
        } 
        }
    } else {
        System.err.println("GLI was unable to send a reconfigure request to the local library server."
               + "\nPlease reconfigure and restart the local Greenstone server manually.");
    }
    }


    static public void stop()
    {
    if (!running) {
        // also the case if the URL is pending in an independently launched GSI
        return;
    }

    // don't (can't) shutdown the GSI/server if it was launched independent of GLI
    if(llssite_cfg_file.isIndependentGSI()) {
        return;
    }

    // Send the command for it to exit.
    if (isPersistentServer) {
        config(QUIT_COMMAND);
    } else {
        boolean success = sendMessageToServer("QUIT\n");
        try {
        if(clientSocketWriter != null) {
            clientSocketWriter.close();
            clientSocketWriter = null;
        }
        clientSocket = null;
        } catch(Exception e) {
        System.err.println("An exception occurred when trying to close the socket"
                   + "\nto the LocalLibraryServer.\n" + e);
        }
        if(success) {       
        Gatherer.terminateApplication(ID);
        } else {
        System.err.println("Unable to stop the server, since there's no communication port to send the quit msg over."
                   + "\nPlease stop the local Greenstone server manually.");        
        }
    }

    // Wait until program has stopped, by reloading and checking the URL field
    llssite_cfg_file.load(false);
    int attempt_count = 0;
    String url = llssite_cfg_file.getURL();
    while (url != null && !url.equals(LLSSiteConfig.URL_PENDING)) { // if pending, the server is already stopped (not running)
        new OneSecondWait();  // Wait one second (give or take)
        llssite_cfg_file.load(false);
        attempt_count++;

        // After waiting for the specified time, ask the user whether they want to wait for that long again
        if (attempt_count == WAITING_TIME) {
        int try_again = JOptionPane.showConfirmDialog(Gatherer.g_man, Dictionary.get("Server.QuitTimeOut", Integer.toString(WAITING_TIME)),
                                  Dictionary.get("General.Warning"), JOptionPane.YES_NO_OPTION);
        if (try_again == JOptionPane.NO_OPTION) {
            return;
        }
        attempt_count = 0;
        }
        // read the url again to see if it's updated
        url = llssite_cfg_file.getURL();
    }

    // Restore the llssite_cfg.
    llssite_cfg_file.restore();

    // If the local server is still running then our changed values will get overwritten.
    url = llssite_cfg_file.getURL();
    if (url != null && !url.equals(LLSSiteConfig.URL_PENDING)) {
        JOptionPane.showMessageDialog(Gatherer.g_man, Dictionary.get("Server.QuitManual"), Dictionary.get("General.Error"), JOptionPane.ERROR_MESSAGE);
    }

    running = false;
    }
    
    static private String getExtraLaunchArguments(LLSSiteConfig site_cfg_file) {
    String args = " " + site_cfg_file.getSiteConfigFilename();

    if(isPersistentServer) {
        return args;
    }
    
    // Else, when running the Local Apache Library Server on Linux/Win, need to provide a port argument
    try {
        PortFinder portFinder = new PortFinder(50100, 100);
        port = portFinder.findPortInRange(false); // silent mode
    } catch(Exception e) {
        System.err.println("Exception when trying to find an available port: " + e);
        port = -1;
    }
    
    return args + " --quitport=" + port;
    }


    // This method first tests whether there is a URL in the llssite_cfg_file 
    // and after that appears, it tests whether the URL is functional.
    static private void testServerRunning() throws IOException {
    // Wait until program has started, by reloading and checking the URL field
    llssite_cfg_file.load(false);
    int attempt_count = 0;
    while (llssite_cfg_file.getURL() == null) {
        new OneSecondWait();  // Wait one second (give or take)
        //System.err.println("**** One Second Wait");
        llssite_cfg_file.load(false);
        attempt_count++;

        // After waiting for the specified time, ask the user whether they want to wait for that long again
        if (attempt_count == WAITING_TIME) {
        int try_again = JOptionPane.showConfirmDialog(Gatherer.g_man, Dictionary.get("Server.StartUpTimeOut", Integer.toString(WAITING_TIME)),
                                  Dictionary.get("General.Warning"), JOptionPane.YES_NO_OPTION);
        if (try_again == JOptionPane.NO_OPTION) {
            return;
        }
        attempt_count = 0;
        }
    }
    
    // Ta-da. Now the url should be available
    try {
        Configuration.library_url = new URL(llssite_cfg_file.getURL());
    }
    catch (MalformedURLException exception) {
        DebugStream.printStackTrace(exception);
    }

    // A quick test involves opening a connection to get the home page for this collection
    try {
        DebugStream.println("Try connecting to server on config url: '" + Configuration.library_url + "'");
        URLConnection connection = Configuration.library_url.openConnection();
        connection.getContent();
        running = true;
    }
    catch (IOException bad_url_connection) {
        throw bad_url_connection;
    }

    
    }

    /** Returns true if we're waiting on the user to click on Enter Library button
     * in an independently launched GSI (one not launched by GLI). */
    static public boolean isURLPending() {
    //if(Configuration.library_url != null) {
    //System.err.println("**** Configuration.library_url: " + Configuration.library_url );
    //return false; // don't need to do anything as we already have the url
    //}

    llssite_cfg_file.load(true); // don't force reload, load only if modified

    String url = llssite_cfg_file.getURL();

    if(url != null) {
        if(url.equals(LLSSiteConfig.URL_PENDING)) {
        running = false; // imagine if they restarted an external GSI
        return true; 
        } else {
        // a valid URL at last
        try {
            Configuration.library_url = new URL(url);
            running = true;
        }
        catch (MalformedURLException exception) {
            running = false;
            exception.printStackTrace();
            DebugStream.printStackTrace(exception);         
        }
        return false;
        }
    }

    // If either the URL is null--which means no independent GSI (Greenstone server interface
    // app) was launched--or if the 'URL' doesn't say it's pending, then we're not waiting
    return false;
    }

    /** @returns true if it had to restart the server. Returns false if it didn't restart it. */
    static public boolean checkServerRunning() {
    boolean serverRestarted = false;

    if (!running) return false; // don't worry about it if it's not supposed to be running 
    llssite_cfg_file.load(true); // don't force reload, load only if modified
    
    String url = llssite_cfg_file.getURL();
    if(url != null) {
        if(url.equals(LLSSiteConfig.URL_PENDING)) {
        running = false;
        return false;
        }

        // else, valid URL:
        try {
        Configuration.library_url = new URL(url);
        running = true;
        }
        catch (MalformedURLException exception) {
        running = false;
        DebugStream.printStackTrace(exception);
        exception.printStackTrace();
        }
    }
    else { // NO URL in current ConfigFile, check the other configfile for a URL 
        // to see if the server was restarted using that file.
        // Otherwise need to restart the server again with GLIsite.cfg
        llssite_cfg_file.save(); // save the configfile, because we may be reloading another

        if(llssite_cfg_file.usingLLS_configFile()) { // if a GSI is already using llssite_cfg, this would have loaded it in
        url = llssite_cfg_file.getURL(); //if(isURLPending()) {
        if(url.equals(LLSSiteConfig.URL_PENDING)) {
            running = false;
        } else {
            running = true;
        }
        return false; // don't need to launch the server, one has been independently launched
        } else {
        // else we try using the glisite configfile
        llssite_cfg_file.useGLISiteCfg(local_library_server_file);
            //llssite_cfg_file.set();
        
        // since we're going to restart the server, make sure to reset all
        // the client socket and its writer (for communicating with the web server) 
        // will only be reinstantiated if they are first nulled
        if(clientSocket != null) {
            clientSocket = null;
        }
        if(clientSocketWriter != null) {
            try{ 
            clientSocketWriter.close();
            clientSocketWriter = null;
            } catch(Exception e) {
            System.err.println("Unable to close the client socket outputstream.");
            } finally {
            clientSocketWriter = null;
            }
        }
        
        // Spawn local library server process
        running = false;
        final String QUOTES = Utility.isWindows() ? "\"" : ""; // need to embed path in quotes on Windows for spaces (interferes on Linux)
        String local_library_server_command = QUOTES+local_library_server_file.getAbsolutePath()+QUOTES + getExtraLaunchArguments(llssite_cfg_file);
        if(Utility.isWindows() && !isPersistentServer) { // launching gs2-web-server.bat (Windows) needs cmd start
            local_library_server_command = "cmd.exe /c start \"GSI\" " + local_library_server_command;
        }
        Gatherer.spawnApplication(local_library_server_command, ID);
        try {
            testServerRunning(); // don't return until the webserver is up and running
            serverRestarted = true;
        } catch (IOException bad_url_connection) {
            DebugStream.println("Can't connect to server on address " + Configuration.library_url);
            running = false;
        }
        }
    }
    return serverRestarted;
    }

    static private class OneSecondWait
    {
    public OneSecondWait()
    {
        synchronized(this) {
        try {
            wait(1000);
        }
        catch (InterruptedException exception) {
        }
        }
    }
    }


    static public class LLSSiteConfig
    extends LinkedHashMap 
    {
    private File configFile;

    private File llssite_cfg;
    private File glisite_cfg;
    private String autoenter_initial;
    private String start_browser_initial;

    private long lastModified = 0;
    
    static final private String AUTOENTER = "autoenter";
    static final private String COLON = ":";
    static final private String ENTERLIB = "enterlib";
    static final private String FALSE = "0";
    static final private String GLISITE_CFG = "glisite.cfg";
    static final private String GSDL = "greenstone"; // httpprefix is no longer /gsdl but /greenstone
    static final private String LLSSITE_CFG = "llssite.cfg";
    static final private String LOCAL_HOST = "http://localhost"; 
    static final private String PORTNUMBER = "portnumber";
    static final private String SEPARATOR = "/";
    static final private String SPECIFIC_CONFIG = "--config=";
    static final private String STARTBROWSER = "start_browser";
    static final private String TRUE = "1";
    static final private String URL = "url";

    static final public String URL_PENDING = "URL_pending";

    
    public LLSSiteConfig(File server_exe) {
        debug("New LLSSiteConfig for: " + server_exe.getAbsolutePath());
        
        llssite_cfg = new File(server_exe.getParentFile(), LLSSITE_CFG);
        glisite_cfg = new File(server_exe.getParentFile(), GLISITE_CFG);

        configFile = null;

        autoenter_initial = null;
        start_browser_initial = null;
        
        // first test if server was started independently of GLI
        // if so, the config file we'd be using would be llssite.cfg
        if(!usingLLS_configFile()) { // if we were using llssite_cfg, this would have loaded it in
        // else we try using the glisite configfile
        useGLISiteCfg(server_exe);
        }
    }

    /** Tries to get a glisite.cfg file and then loads it, setting it as the configFile */
    public void useGLISiteCfg(File server_exe)
    {
        if(!glisite_cfg.exists()) { // create it from the templates or the llssite.cfg file
        
        File llssite_cfg_in = new File(server_exe.getParentFile(), LLSSITE_CFG+".in");
        File glisite_cfg_in = new File(server_exe.getParentFile(), GLISITE_CFG+".in");
        
        // need to generate glisite_cfg from glisite_cfg_in, llssite_cfg or llssite.cfg.in
        if(glisite_cfg_in.exists()) {
            copyConfigFile(glisite_cfg_in, glisite_cfg, false);    
        } 
        else if(llssite_cfg_in.exists()) { 
            copyConfigFile(llssite_cfg_in, glisite_cfg_in, true); // adjust for glisite.cfg
            copyConfigFile(glisite_cfg_in, glisite_cfg, false);    
        }
        else if(llssite_cfg.exists()) {
            copyConfigFile(llssite_cfg, glisite_cfg, true);        // adjust for glisite.cfg
        }
        else {
            debug("Neither the file glisite.cfg nor llssite.cfg can be found!");
        }
        }
        // use the config file now
        if(glisite_cfg.exists()) {
        configFile = glisite_cfg;
        load(false); // force reload
        lastModified = configFile.lastModified();
        } 
    }

    /** Tests whether the server interface is up, running independently of GLI
     * If so, we don't need to launch the server interface.
     * The server interface may not have started up the server itself though
     * (in which case the server URL would be URL_PENDING).
     * This method returns true if the server interface has already started
     * and, if so, it would have loaded in the llssite_cfg configFile.
     */
    public boolean usingLLS_configFile() {
        if(!llssite_cfg.exists()) {
        return false;
        }

        // Now to check if the configfile contains the URL line
        configFile = llssite_cfg;
        load(false); // force load

        if(getURL() == null) {
        configFile = null;
        clear(); // we're not using llssite_cfg, so clear the values we just read
        return false;
        }

        lastModified = configFile.lastModified();
        return true;
    }

    /** To test we've actually instantiated this object meaningfully. If so, then configFile is set */
    public boolean isConfigFileSet() {
        return (configFile != null && configFile.exists());
    }
    
    /** @return true if GSI was started up independently and outside of GLI. 
     * In such a case, GLI would be using llssite_cfg. */
    public boolean isIndependentGSI() {
        return (configFile == llssite_cfg);
    }

    public boolean exists() {
        return configFile.exists();
    }

    public String getLocalHostURL() {
        StringBuffer url = new StringBuffer(LOCAL_HOST);
        url.append(COLON);
        url.append((String)get(PORTNUMBER));
        String enterlib = (String)get(ENTERLIB);
        if(!isPersistentServer || enterlib == null || enterlib.length() == 0) {
        // Use the default /gsdl and hope for the best.
        url.append(SEPARATOR);
        url.append(GSDL);
        }
        else {
        if(!enterlib.startsWith(SEPARATOR)) {
            url.append(SEPARATOR);
        }
        url.append(enterlib);
        }
        enterlib = null;
        debug("Found Local Library Address: " + url.toString());
        return url.toString();
    }

    /** @return the cmd-line parameter for the configfile used to launch
     * the server through GLI: --config <glisite.cfg/llssite.cfg file path>. */
    public String getSiteConfigFilename() {
        return SPECIFIC_CONFIG + configFile.getAbsolutePath();
    }

    public String getURL() {
        // URL is made from url and portnumber
        String url = (String) get(URL);

        // server interface is already up, independent of GLI
        // but it has not started the server (hence URL is pending) 
        if(url != null && url.equals(URL_PENDING)) {
        return url;
        }

        if(!isPersistentServer) {
        return url;
        }

        if(url != null) {
        StringBuffer temp = new StringBuffer(url);
        temp.append(COLON);
        temp.append((String)get(PORTNUMBER));
        String enterlib = (String)get(ENTERLIB);
        if(enterlib == null || enterlib.length() == 0) {
            // Use the default /greenstone prefix and hope for the best.
            temp.append(SEPARATOR);
            temp.append(GSDL);
        }
        else {
            if(!enterlib.startsWith(SEPARATOR)) {
            temp.append(SEPARATOR);
            }
            temp.append(enterlib);
        }
        enterlib = null;
        url = temp.toString();
        }
        debug("Found Local Library Address: " + url);
        return url;
    }

    public void setLastModified() {
        if(isModified()) {
        lastModified = configFile.lastModified();
        } 
    }

    public boolean isModified() {
        return (lastModified != configFile.lastModified());
    }

    public void load(boolean reloadOnlyIfModified) {        

        if(configFile == null) {
        debug(configFile.getAbsolutePath() + " cannot be found!");
        }

        if(isModified()) {
        lastModified = configFile.lastModified();
        } else if(reloadOnlyIfModified) {
        return; // asked to reload only if modified. Don't reload since not modified
        }

        if(configFile.exists()) {
        debug("Load: " + configFile.getAbsolutePath());
        clear();
        try {
            BufferedReader in = new BufferedReader(new FileReader(configFile));
            String line = null;
            while((line = in.readLine()) != null) {
            String key = null;
            String value = null;
            int index = -1;
            if((index = line.indexOf("=")) != -1 && line.length() >= index + 1) {
                key = line.substring(0, index);
                value = line.substring(index + 1);
            }
            else {
                key = line;
            }
            put(key, value);
            }
            in.close();
        }
        catch (Exception error) {
            error.printStackTrace();
        }
        }
        else {
        debug(configFile.getAbsolutePath() + " cannot be found!");
        }
    }

    /** Restore the autoenter value to its initial value, and remove url if present. */
    public void restore() {
        if(configFile != null) {
        // Delete the file
        configFile.delete();
        }
        else {
        debug("Restore Initial Settings");
        put(AUTOENTER, autoenter_initial);
        put(STARTBROWSER, start_browser_initial);
        remove(URL);
        save();
        }
    }

    public void set() {
        debug("Set Session Settings");
        if(autoenter_initial == null) {
        autoenter_initial = (String) get(AUTOENTER);
        debug("Remember autoenter was: " + autoenter_initial);
        }
        put(AUTOENTER, TRUE);
        if(start_browser_initial == null) {
        start_browser_initial = (String) get(STARTBROWSER);
        debug("Remember start_browser was: " + start_browser_initial);
        }
        put(STARTBROWSER, FALSE);
        save();
    }

    private void debug(String message) {
        ///ystem.err.println(message);
    }

    private void save() {
        //debug("Save: " + llssite_cfg.getAbsolutePath());
        debug("Save: " + configFile.getAbsolutePath());
        try {
        //BufferedWriter out = new BufferedWriter(new FileWriter(llssite_cfg, false));
        BufferedWriter out = new BufferedWriter(new FileWriter(configFile, false));
        for(Iterator keys = keySet().iterator(); keys.hasNext(); ) {
            String key = (String) keys.next();
            String value = (String) get(key);
            out.write(key, 0, key.length());
            if(value != null) {
            out.write('=');
            
            // if the server is using llssite.cfg, don't overwrite its default
            // autoenter and startbrowser values
            if(configFile == llssite_cfg && (key == AUTOENTER || key == STARTBROWSER)) {
                if(key == AUTOENTER) {
                out.write(autoenter_initial, 0, autoenter_initial.length());
                } else { // STARTBROWSER
                out.write(start_browser_initial, 0, start_browser_initial.length());
                }
             } else {
                 out.write(value, 0, value.length());
            }
            }
            out.newLine();
        }
        out.flush();
        out.close();
        }
        catch (Exception error) {
        error.printStackTrace();
        }
    }

    private static void copyConfigFile(File source_cfg, File dest_cfg, boolean setToGliSiteDefaults) {
        // source_cfg file should exist
        // dest_cfg file should not yet exist
        // If setToGliSiteDefaults is true, then GLIsite.cfg's default configuration 
        // is applied to concerned lines: autoenter=1, and startbrowser=0

        try {
        BufferedReader in = new BufferedReader(new FileReader(source_cfg));
        BufferedWriter out = new BufferedWriter(new FileWriter(dest_cfg, false));
        
        String line = null;
        while((line = in.readLine()) != null) {
            
            if(setToGliSiteDefaults) {
            if(line.startsWith(AUTOENTER)) {
                line = AUTOENTER+"=1";
            }
            else if(line.startsWith(STARTBROWSER)) {
                line = STARTBROWSER+"=0";
            }
            }
        
            // write out the line
            out.write(line + "\n");
        }
        
        out.flush();
        in.close();
        out.close();
        } catch(Exception e) {
        System.err.println("Exception occurred when trying to copy the config file "
                   + source_cfg.getName() + " to " + dest_cfg.getName() + ": " + e);
        e.printStackTrace();
        }
    }
    }
}