source: trunk/gli/src/org/greenstone/gatherer/LocalLibraryServer.java@ 11574

/**
 *############################################################################
 * 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;


import java.io.*;
import java.lang.*;
import java.net.*;
import javax.swing.*;
import org.greenstone.gatherer.util.GSDLSiteConfig;


public class LocalLibraryServer
{
    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 GSDLSiteConfig gsdlsite_cfg_file = null;
    static private File local_library_server_file = null;

    static private boolean running = false;

    static public void addCollection(String collection_name)
    {
    config(ADD_COMMAND + collection_name);
    // This is very important -- it ensures that the above command has finished
    config("");
    }


    // Used to send messages to the local library
    // Warning: this has a lot of potential for nasty race conditions
    // The response code is returned immediately -- but this does not mean the local
    //   library action has finished!
    static private void config(String command)
    {
    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();
        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 ex) {
        DebugStream.printStackTrace(ex);
    }
    }


    static public boolean isRunning()
    {
    if (!running) return false;
    gsdlsite_cfg_file.load();
    if (gsdlsite_cfg_file.getURL() == null)  return false;
    return true;
    }

    static public void releaseCollection(String collection_name)
    {
    config(RELEASE_COMMAND + collection_name);
    // This is very important -- it ensures that the above command has finished
    config("");

    // !! HACK: Wait a couple of seconds, in the hope that this will reduce the "could not delete index" errors
    new OneSecondWait();
    new OneSecondWait();
    }


    static public void start(String gsdl_path, String local_library_server_file_path)
    {
    // Check the local library server.exe file exists
    local_library_server_file = new File(local_library_server_file_path);
    if (!local_library_server_file.exists()) {
        DebugStream.println("No local library at given file path.");

        local_library_server_file = new File(gsdl_path + "server.exe");
        if (!local_library_server_file.exists()) {
        DebugStream.println("No local library at all.");
        return;
        }
    }

    // Check if the server is already running
    gsdlsite_cfg_file = new GSDLSiteConfig(local_library_server_file);
    String url = gsdlsite_cfg_file.getURL();
    if (url != null) {
        // If it is already running then set the Greenstone web server address and we're done
        try {
        Configuration.library_url = new URL(url);
        running = true;
        return;
        }
        catch (MalformedURLException exception) {
        DebugStream.printStackTrace(exception);
        }
    }

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

    // Spawn local library server process
    String local_library_server_command = local_library_server_file.getAbsolutePath() + " " + gsdlsite_cfg_file.getSiteConfigFilename();
    Gatherer.spawnApplication(local_library_server_command);

    // Wait until program has started, by reloading and checking the URL field
    gsdlsite_cfg_file.load();
    int attempt_count = 0;
    while (gsdlsite_cfg_file.getURL() == null) {
        new OneSecondWait();  // Wait one second (give or take)
        gsdlsite_cfg_file.load();
        attempt_count++;

        // After waiting a minute ask the user whether they want to wait another minute
        if (attempt_count == 60) {
        int try_again = JOptionPane.showConfirmDialog(Gatherer.g_man, Dictionary.get("Server.QuitTimeOut"), 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(gsdlsite_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();
    }
    catch (IOException bad_url_connection) {
        try {
        // If this fails then we try changing the url to be localhost
        Configuration.library_url = new URL(gsdlsite_cfg_file.getLocalHostURL());
        DebugStream.println("Try connecting to server on local host: '" + Configuration.library_url + "'");
        URLConnection connection = Configuration.library_url.openConnection();
        connection.getContent();
        }
        catch (IOException worse_url_connection) {
        DebugStream.println("Can't connect to server on either address.");
        Configuration.library_url = null;
        return;
        }
    }

    running = true;
    }


    static public void stop()
    {
    if (running == false) {
        return;
    }

    // Send the command for it to exit.
    config(QUIT_COMMAND);

    // Wait until program has stopped, by reloading and checking the URL field
    gsdlsite_cfg_file.load();
    int attempt_count = 0;
    while (gsdlsite_cfg_file.getURL() != null) {
        new OneSecondWait();  // Wait one second (give or take)
        gsdlsite_cfg_file.load();
        attempt_count++;

        // After waiting a minute ask the user whether they want to wait another minute
        if (attempt_count == 60) {
        int try_again = JOptionPane.showConfirmDialog(Gatherer.g_man, Dictionary.get("Server.QuitTimeOut"), Dictionary.get("General.Warning"), JOptionPane.YES_NO_OPTION);
        if (try_again == JOptionPane.NO_OPTION) {
            return;
        }
        attempt_count = 0;
        }
    }

    // Restore the gsdlsite_cfg.
    gsdlsite_cfg_file.restore();

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

    running = false;
    }
    
    static public void checkServerRunning() {
    if (!running) return; // don't worry about it if its not supposed to be running 
    gsdlsite_cfg_file.load();
    if (gsdlsite_cfg_file.getURL() == null) {
        // need to restart the server again
        gsdlsite_cfg_file.set();

        // Spawn local library server process
        String local_library_server_command = local_library_server_file.getAbsolutePath() + " " + gsdlsite_cfg_file.getSiteConfigFilename();
        Gatherer.spawnApplication(local_library_server_command);

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