001package org.apache.turbine.modules.screens;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *   http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import java.io.BufferedReader;
023import java.io.CharArrayWriter;
024import java.io.InputStreamReader;
025import java.io.OutputStreamWriter;
026import java.io.PrintWriter;
027
028import javax.servlet.http.HttpServletRequest;
029
030import org.apache.turbine.annotation.TurbineService;
031import org.apache.turbine.pipeline.PipelineData;
032import org.apache.turbine.services.jsonrpc.JsonRpcService;
033import org.apache.turbine.util.RunData;
034import org.jabsorb.JSONRPCBridge;
035
036
037/**
038 * A Screen class for dealing with JSON-RPC requests.  Typically you would
039 * extend this class and override the doOutput() method to use TurbineJsonRpc
040 * to register the POJOs that will provide the functions you are making
041 * available via JSON-RPC.  Use JSONSecureScreen if you need the user to be
042 * logged in prior to executing the functions you provide.
043 *
044 * <p>Here is an example from a superclass:
045 * <code>
046 * public void doOutput(PipelineData data) throws Exception
047 * {
048 *     User user = data.getUser();
049 *
050 *     MyJsonFunctions myFunctions = new MyJsonFunctions(user.getName());
051 *
052 *     // Session specific
053 *     TurbineJsonRpc.registerObject(data.getSession(), "myFunctions", myFunctions);
054 *
055 *     // Global
056 *     //TurbineJsonRpc.registerObjectGlobal("testGlobal", testObject);
057 *
058 *     super.doOutput(data);
059 * }
060 * </code>
061 *
062 * <p>The class MyFunctions would be something like:
063 * <code>
064 * public class MyJsonFunctions
065 * {
066 *     private String getHello(String clientParameter)
067 *     {
068 *         return "Hello " + clientParameter;
069 *     }
070 * }
071 * </code>
072 *
073 * <p>This code is derived from the com.metaparadigm.jsonrpc.JSONRPCServlet and (after upgrade) checked against
074 * org.jabsorb.JSONRPCServlet.
075 *
076 * @author brad@folkens.com
077 * @author <a href="mailto:seade@backstagetech.com.au">Scott Eade</a>
078 * @version $Id: JSONScreen.java 1812628 2017-10-19 12:34:25Z gk $
079 */
080public class JSONScreen extends RawScreen
081{
082    protected static final String JSONRPC_CONTENT_TYPE = "application/json;charset=utf-8";
083
084    protected final static int BUFFER_SIZE = 4096;
085
086    /** Injected service instance */
087    @TurbineService
088    protected JsonRpcService jsonRpcService;
089
090    /**
091     * @see org.apache.turbine.modules.screens.RawScreen#getContentType(org.apache.turbine.pipeline.PipelineData)
092     */
093    @Override
094    protected String getContentType(PipelineData pipelineData)
095    {
096        return JSONRPC_CONTENT_TYPE;
097    }
098
099    /**
100     * Output the dynamic content.
101     *
102     * Encodign is UTF-8. @{@link #JSONRPC_CONTENT_TYPE}: {@value #JSONRPC_CONTENT_TYPE}.
103     *
104     * @param pipelineData The PipelineData object.
105     */
106    @Override
107    protected void doOutput(PipelineData pipelineData) throws Exception
108    {
109        RunData data = getRunData(pipelineData);
110        data.declareDirectResponse();
111        HttpServletRequest request = data.getRequest();
112
113        // we require utf-8, cft
114        String charset =  "UTF-8"; //request.getCharacterEncoding();
115        BufferedReader in = new BufferedReader(new InputStreamReader(request.getInputStream(), charset));
116
117        // Read the request
118        CharArrayWriter cdata = new CharArrayWriter();
119        char buf[] = new char[BUFFER_SIZE];
120        int ret;
121        while ((ret = in.read(buf, 0, BUFFER_SIZE)) != -1)
122        {
123            cdata.write(buf, 0, ret);
124        }
125
126        // Find the JSONRPCBridge for this session or create one
127        // if it doesn't exist
128        JSONRPCBridge json_bridge = jsonRpcService.getBridge(data.getSession());
129
130        // Process the request
131        Object json_res = jsonRpcService.processCall(cdata, json_bridge, request);
132
133        PrintWriter out = new PrintWriter(
134                new OutputStreamWriter(data.getResponse().getOutputStream(),charset));
135        out.print(json_res.toString());
136        out.flush();
137        out.close();
138    }
139}