JsonRpcHttpRequestHandler.java

/*
 * (C) Copyright 2013 Kurento (http://kurento.org/)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package org.kurento.jsonrpc.internal.http;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.kurento.jsonrpc.client.Continuation;
import org.kurento.jsonrpc.internal.JsonRpcRequestSenderHelper;
import org.kurento.jsonrpc.internal.client.TransactionImpl.ResponseSender;
import org.kurento.jsonrpc.internal.server.ProtocolManager;
import org.kurento.jsonrpc.internal.server.ProtocolManager.ServerSessionFactory;
import org.kurento.jsonrpc.internal.server.ServerSession;
import org.kurento.jsonrpc.internal.server.SessionsManager;
import org.kurento.jsonrpc.message.Message;
import org.kurento.jsonrpc.message.Request;
import org.kurento.jsonrpc.message.Response;
import org.springframework.web.HttpRequestHandler;

import com.google.common.io.CharStreams;
import com.google.gson.JsonElement;

public class JsonRpcHttpRequestHandler implements HttpRequestHandler {

  private final class HttpRequestServerSession extends ServerSession {

    private HttpRequestServerSession(String sessionId, Object registerInfo,
        SessionsManager sessionsManager, String internalSessionId) {

      super(sessionId, registerInfo, sessionsManager, internalSessionId);

      setRsHelper(new JsonRpcRequestSenderHelper(sessionId) {

        @Override
        protected <P, R> Response<R> internalSendRequest(Request<P> request, Class<R> resultClass)
            throws IOException {
          // TODO Poner aquí la cola de mensajes que devolver al
          // cliente cuando haga pooling
          return new Response<>();
        }

        @Override
        protected void internalSendRequest(Request<? extends Object> request,
            Class<JsonElement> class1, Continuation<Response<JsonElement>> continuation) {
          throw new UnsupportedOperationException("Async client is unavailable");
        }
      });
    }

    @Override
    public void handleResponse(Response<JsonElement> response) {
    }

    @Override
    public void closeNativeSession(String reason) {
      throw new UnsupportedOperationException();
    }
  }

  private final ProtocolManager protocolManager;

  public JsonRpcHttpRequestHandler(ProtocolManager protocolManager) {
    this.protocolManager = protocolManager;
  }

  @Override
  public void handleRequest(HttpServletRequest servletRequest,
      final HttpServletResponse servletResponse) throws ServletException, IOException {

    String messageJson = getBodyAsString(servletRequest);

    ServerSessionFactory factory = new ServerSessionFactory() {
      @Override
      public ServerSession createSession(String sessionId, Object registerInfo,
          SessionsManager sessionsManager) {

        return new HttpRequestServerSession(sessionId, registerInfo, sessionsManager, null);
      }

      @Override
      public void updateSessionOnReconnection(ServerSession session) {
        throw new UnsupportedOperationException();
      }
    };

    ResponseSender responseSender = new ResponseSender() {
      @Override
      public void sendResponse(Message message) throws IOException {
        servletResponse.getWriter().println(message);
      }

      @Override
      public void sendPingResponse(Message message) throws IOException {
        sendResponse(message);
      }
    };

    String internalSessionId = null;

    HttpSession session = servletRequest.getSession(false);
    if (session != null) {
      internalSessionId = session.getId();
    }

    protocolManager.processMessage(messageJson, factory, responseSender, internalSessionId);
  }

  /**
   *
   * @param request
   * @return
   * @throws IOException
   */
  private String getBodyAsString(final HttpServletRequest request) throws IOException {
    return CharStreams.toString(request.getReader());
  }

}