001/*
002 * Copyright (c) 2011-2017 Nexmo Inc
003 *
004 * Permission is hereby granted, free of charge, to any person obtaining a copy
005 * of this software and associated documentation files (the "Software"), to deal
006 * in the Software without restriction, including without limitation the rights
007 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
008 * copies of the Software, and to permit persons to whom the Software is
009 * furnished to do so, subject to the following conditions:
010 *
011 * The above copyright notice and this permission notice shall be included in
012 * all copies or substantial portions of the Software.
013 *
014 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
015 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
016 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
017 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
018 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
019 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
020 * THE SOFTWARE.
021 */
022package com.nexmo.client.voice.servlet;
023
024import javax.servlet.ServletException;
025import javax.servlet.http.HttpServlet;
026import javax.servlet.http.HttpServletRequest;
027import javax.servlet.http.HttpServletResponse;
028import java.io.IOException;
029
030/**
031 * Useful abstract HttpServlet for implementing NCCO callbacks.
032 * <p>
033 *     Implement {@link #handleRequest(HttpServletRequest)} to return an {@link NccoResponse} and this servlet will
034 *     ensure that the response is serialized correctly for the Nexmo Voice API.
035 * </p>
036 */
037public abstract class AbstractAnswerServlet extends HttpServlet {
038    @Override
039    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
040        serializeNccoResponse(resp, this.handleRequest(req));
041    }
042
043    @Override
044    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
045        serializeNccoResponse(resp, this.handleRequest(req));
046    }
047
048    private void serializeNccoResponse(HttpServletResponse httpResponse, NccoResponse nccoResponse) throws IOException {
049        byte[] json = nccoResponse.toJson().getBytes("UTF-8");
050        httpResponse.setCharacterEncoding("UTF-8");
051        httpResponse.setContentType("application/json");
052        httpResponse.setContentLength(json.length);
053        httpResponse.getOutputStream().write(json);
054    }
055
056    /**
057     * Handle a request for NCCO instructions from the Nexmo Voice API.
058     * <p>
059     * Implementations should return an NccoResponse object (most easily constructed using {@link NccoResponseBuilder}.
060     *
061     * @param request the HttpServletRequest parsed from the request made by the Nexmo Voice API
062     * @return An NccoResponse containing Ncco instructions for the Nexmo Voice API
063     */
064    protected abstract NccoResponse handleRequest(HttpServletRequest request);
065}