AbstractBaseProtocolNegotiator.java

/*
 * Copyright (c) 2015-2016, Christoph Engelbert (aka noctarius) and
 * contributors. All rights reserved.
 *
 * 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 com.noctarius.tengi.server.impl.transport.base;

import com.noctarius.tengi.server.impl.ConnectionManager;
import com.noctarius.tengi.server.impl.transport.NettyNegotiator;
import com.noctarius.tengi.server.impl.transport.ServerConnectionProcessor;
import com.noctarius.tengi.server.spi.negotiation.NegotiationContext;
import com.noctarius.tengi.server.spi.negotiation.NegotiationResult;
import com.noctarius.tengi.spi.serialization.Serializer;
import com.noctarius.tengi.spi.serialization.impl.DefaultProtocolConstants;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;

public abstract class AbstractBaseProtocolNegotiator
        implements NettyNegotiator {

    @Override
    public NegotiationResult handleProtocol(NegotiationContext context, ChannelHandlerContext ctx, ByteBuf buffer) {
        if (buffer.readableBytes() < 5) {
            // Not enough data to negotiate the protocol's magic header
            return NegotiationResult.InsufficientBuffer;
        }

        // Read the magic header
        int magic0 = buffer.getUnsignedByte(buffer.readerIndex());
        int magic1 = buffer.getUnsignedByte(buffer.readerIndex() + 1);
        int magic2 = buffer.getUnsignedByte(buffer.readerIndex() + 2);
        int magic3 = buffer.getUnsignedByte(buffer.readerIndex() + 3);
        int magic4 = buffer.getUnsignedByte(buffer.readerIndex() + 4);

        if (magic0 == 'T' && magic1 == 'e' && magic2 == 'N' && magic3 == 'g' && magic4 == 'I') {
            buffer.skipBytes(DefaultProtocolConstants.PROTOCOL_MAGIC_HEADER.length);

            Serializer serializer = context.getSerializer();
            ConnectionManager connectionManager = context.getConnectionManager();

            ChannelPipeline pipeline = ctx.pipeline();
            pipeline.addLast("tcp-connection-processor", getConnectionProcessor(connectionManager, serializer));
            return NegotiationResult.Successful;
        }

        return NegotiationResult.Continue;
    }

    protected abstract ServerConnectionProcessor<ByteBuf> getConnectionProcessor(ConnectionManager connectionManager,
                                                                                 Serializer serializer);
}