agk.chatbot.web.MainServlet.java Source code

Introduction

Here is the source code for agk.chatbot.web.MainServlet.java

Source

/*
 * Copyright (C) 2016, 2017 Aaron Keesing
 * 
 * This file is part of CBR Chat Bot.
 * 
 * CBR Chat Bot 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 3 of the License, or (at your option) any later
 * version.
 * 
 * CBR Chat Bot 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
 * CBR Chat Bot. If not, see <http://www.gnu.org/licenses/>.
 */

package agk.chatbot.web;

import java.io.FileNotFoundException;
import java.io.IOException;

import javax.servlet.*;
import javax.servlet.http.*;

import org.json.JSONException;
import org.json.JSONObject;

import agk.chatbot.*;
import agk.chatbot.cbr.ChatResponse;
import agk.chatbot.nlp.OpenNLPAnnotator;
import jcolibri.cbrcore.CBRQuery;
import jcolibri.exception.ExecutionException;

/**
 * This is the main servlet for taking requests of user input and sending back
 * the bot's responses.
 * 
 * @version 2.3
 */
public class MainServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    static ChatBot bot;
    static boolean initialised;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public MainServlet() {
        super();
        initialised = false;
        bot = null;
    }

    /**
     * @see Servlet#init(ServletConfig)
     */
    @Override
    public void init(ServletConfig config) throws ServletException {
        if (bot == null) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        bot = new ChatBot(null, OpenNLPAnnotator.class);
                        bot.configure();
                        bot.preCycle();
                        initialised = true;
                    } catch (ExecutionException e) {
                        e.printStackTrace();
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    }
                }
            }).start();
        }
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        JSONObject json = new JSONObject();
        int status;
        response.addHeader("Content-Type", "application/json");
        try {
            status = 200;
            json.put("status", status);
            json.put("result", initialised);
        } catch (JSONException e) {
            status = 500;
            e.printStackTrace();
        }
        response.setStatus(status);
        response.getWriter().print(json.toString());
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
     *      response)
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        int status = 200;
        String result = "";
        JSONObject json = new JSONObject();
        response.addHeader("Content-Type", "application/json");

        if (initialised) {
            if (request.getHeader("Content-Type").startsWith("application/x-www-form-urlencoded")) {
                String chat = request.getParameter("c");
                if (chat.length() == 0 || chat.length() > 140) {
                    status = 400;
                    result = "Bad request. Invalid chat message.";
                } else {
                    try {
                        CBRQuery query = bot.strToQuery(chat);
                        bot.cycle(query);
                        ChatResponse resp = bot.getLastResponse();
                        status = 200;
                        result = resp.getText().toString();
                    } catch (ExecutionException e) {
                        status = 500;
                        result = "An error occurred.";
                        e.printStackTrace();
                    }
                }
            } else {
                status = 400;
                result = "Bad request. Requires Content-Type: application/x-www-form-urlencoded";
            }
        } else {
            status = 503;
            result = "Bot is still initialising.";
        }

        try {
            json.put("status", 400);
            json.put("result", result);
        } catch (JSONException e) {
            status = 500;
            e.printStackTrace();
        }
        response.setStatus(status);
        response.getWriter().print(json.toString());
    }

    /**
     * Deinits the servlet and destroys the associated bot.
     */
    @Override
    public void destroy() {
        try {
            bot.postCycle();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
        bot = null;
        System.out.println("Servlet destroyed.");
    }
}