RequestDecoder.java

/*
 * Copyright 2014-2016 CyberVision, Inc.
 *
 * 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.kaaproject.kaa.server.transports.http.transport.netty;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.codec.DecoderResult;
import io.netty.handler.codec.http.HttpMethod;
import io.netty.handler.codec.http.HttpObject;
import io.netty.handler.codec.http.HttpRequest;
import io.netty.handler.codec.http.HttpResponse;
import io.netty.util.Attribute;

import org.kaaproject.kaa.server.common.server.AbstractNettyServer;
import org.kaaproject.kaa.server.common.server.BadRequestException;
import org.kaaproject.kaa.server.common.server.CommandFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.UUID;

/**
 * RequestDecoder Class. ChannelInboundHandler for HttpObject in Netty pipeline.
 * On channelRead0() check HTTP METHOD POST, and find CommandProcessor for HTTP
 * request URI. Then pass CommandProcessor to next handler in pipeline.
 *
 * @author Andrey Panasenko
 */
public class RequestDecoder extends SimpleChannelInboundHandler<HttpObject> {
  private static final Logger LOG = LoggerFactory.getLogger(RequestDecoder.class);

  private final CommandFactory<HttpRequest, HttpResponse> commandFactory;

  public RequestDecoder(CommandFactory<HttpRequest, HttpResponse> commandFactory) {
    super();
    this.commandFactory = commandFactory;
  }

  @Override
  protected void channelRead0(ChannelHandlerContext ctx, HttpObject httpObject) throws Exception {

    DecoderResult result = httpObject.getDecoderResult();
    if (!result.isSuccess()) {
      throw new BadRequestException(result.cause());
    }

    Attribute<UUID> sessionUuidAttr = ctx.channel().attr(AbstractNettyServer.UUID_KEY);

    if (httpObject instanceof HttpRequest) {
      HttpRequest httpRequest = (HttpRequest) httpObject;
      LOG.trace("Session: {} got valid HTTP request:\n{}",
              sessionUuidAttr.get().toString(), httpRequest.headers().toString());
      if (httpRequest.getMethod().equals(HttpMethod.POST)) {
        String uri = httpRequest.getUri();
        AbstractCommand cp = (AbstractCommand) commandFactory.getCommandProcessor(uri);
        cp.setSessionUuid(sessionUuidAttr.get());
        cp.setRequest(httpRequest);
        cp.parse();
        ctx.fireChannelRead(cp);
      } else {
        LOG.error("Got invalid HTTP method: expecting only POST");
        throw new BadRequestException(
                "Incorrect method " + httpRequest.getMethod().toString() + ", expected POST"
        );
      }
    } else {
      LOG.warn("Session: {} got invalid HTTP object:\n{}",
              sessionUuidAttr.get().toString(), httpObject);
    }
  }
}