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    1   package org.apache.turbine.modules.screens;
    2
    3   /*
    4    * Licensed to the Apache Software Foundation (ASF) under one
    5    * or more contributor license agreements.  See the NOTICE file
    6    * distributed with this work for additional information
    7    * regarding copyright ownership.  The ASF licenses this file
    8    * to you under the Apache License, Version 2.0 (the
    9    * "License"); you may not use this file except in compliance
    10   * with the License.  You may obtain a copy of the License at
    11   *
    12   *   http://www.apache.org/licenses/LICENSE-2.0
    13   *
    14   * Unless required by applicable law or agreed to in writing,
    15   * software distributed under the License is distributed on an
    16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    17   * KIND, either express or implied.  See the License for the
    18   * specific language governing permissions and limitations
    19   * under the License.
    20   */
    21
    22  import java.io.BufferedReader;
    23  import java.io.CharArrayWriter;
    24  import java.io.InputStreamReader;
    25  import java.io.OutputStreamWriter;
    26  import java.io.PrintWriter;
    27
    28  import javax.servlet.http.HttpServletRequest;
    29
    30  import org.apache.turbine.annotation.TurbineService;
    31  import org.apache.turbine.pipeline.PipelineData;
    32  import org.apache.turbine.services.jsonrpc.JsonRpcService;
    33  import org.apache.turbine.util.RunData;
    34  import org.jabsorb.JSONRPCBridge;
    35
    36
    37  /**
    38   * A Screen class for dealing with JSON-RPC requests.  Typically you would
    39   * extend this class and override the doOutput() method to use TurbineJsonRpc
    40   * to register the POJOs that will provide the functions you are making
    41   * available via JSON-RPC.  Use JSONSecureScreen if you need the user to be
    42   * logged in prior to executing the functions you provide.
    43   *
    44   * <p>Here is an example from a superclass:
    45   * <code>
    46   * public void doOutput(PipelineData data) throws Exception
    47   * {
    48   *     User user = data.getUser();
    49   *
    50   *     MyJsonFunctions myFunctions = new MyJsonFunctions(user.getName());
    51   *
    52   *     // Session specific
    53   *     TurbineJsonRpc.registerObject(data.getSession(), "myFunctions", myFunctions);
    54   *
    55   *     // Global
    56   *     //TurbineJsonRpc.registerObjectGlobal("testGlobal", testObject);
    57   *
    58   *     super.doOutput(data);
    59   * }
    60   * </code>
    61   *
    62   * <p>The class MyFunctions would be something like:
    63   * <code>
    64   * public class MyJsonFunctions
    65   * {
    66   *     private String getHello(String clientParameter)
    67   *     {
    68   *         return "Hello " + clientParameter;
    69   *     }
    70   * }
    71   * </code>
    72   *
    73   * <p>This code is derived from the com.metaparadigm.jsonrpc.JSONRPCServlet and (after upgrade) checked against
    74   * org.jabsorb.JSONRPCServlet.
    75   *
    76   * @author brad@folkens.com
    77   * @author <a href="mailto:seade@backstagetech.com.au">Scott Eade</a>
    78   * @version $Id: JSONScreen.java 1718292 2015-12-07 10:23:44Z gk $
    79   */
    80  public class JSONScreen extends RawScreen
    81  {
    82      protected static final String JSONRPC_CONTENT_TYPE = "application/json;charset=utf-8";
    83
    84      protected final static int BUFFER_SIZE = 4096;
    85
    86      /** Injected service instance */
    87      @TurbineService
    88      private JsonRpcService jsonRpcService;
    89
    90      /**
    91       * @see org.apache.turbine.modules.screens.RawScreen#getContentType(org.apache.turbine.pipeline.PipelineData)
    92       */
    93      @Override
    94      protected String getContentType(PipelineData pipelineData)
    95      {
    96          return JSONRPC_CONTENT_TYPE;
    97      }
    98
    99      /**
    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 }