/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.apache.giraph.comm.netty.handler;
  
  import org.apache.giraph.comm.netty.NettyServer;
  import org.apache.giraph.comm.netty.SaslNettyServer;
  import org.apache.log4j.Logger;
  
  import io.netty.channel.ChannelInboundHandlerAdapter;
  import io.netty.channel.ChannelHandlerContext;
  /**
   * Authorize or deny client requests based on existence and completeness
   * of client's SASL authentication.
   */
  public class AuthorizeServerHandler extends
      ChannelInboundHandlerAdapter {
    /** Class logger */
    private static final Logger LOG =
        Logger.getLogger(AuthorizeServerHandler.class);
  
    /**
     * Constructor.
     */
    public AuthorizeServerHandler() {
    }
  
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg)
      throws Exception {
      if (LOG.isDebugEnabled()) {
        LOG.debug("messageReceived: Got " + msg.getClass());
      }
      // Authorize: client is allowed to doRequest() if and only if the client
      // has successfully authenticated with this server.
      SaslNettyServer saslNettyServer =
          ctx.attr(NettyServer.CHANNEL_SASL_NETTY_SERVERS).get();
      if (saslNettyServer == null) {
        LOG.warn("messageReceived: This client is *NOT* authorized to perform " +
            "this action since there's no saslNettyServer to " +
            "authenticate the client: " +
            "refusing to perform requested action: " + msg);
        return;
      }
  
      if (!saslNettyServer.isComplete()) {
        LOG.warn("messageReceived: This client is *NOT* authorized to perform " +
            "this action because SASL authentication did not complete: " +
            "refusing to perform requested action: " + msg);
        // Return now *WITHOUT* sending upstream here, since client
        // not authorized.
        return;
      }
      if (LOG.isDebugEnabled()) {
        LOG.debug("messageReceived: authenticated client: " +
            saslNettyServer.getUserName() + " is authorized to do request " +
            "on server.");
      }
      // We call fireChannelRead since the client is allowed to perform this
      // request. The client's request will now proceed to the next
      // pipeline component, namely, RequestServerHandler.
      ctx.fireChannelRead(msg);
    }
  }