c5db.codec.WebsocketProtostuffEncoder.java Source code

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Here is the source code for c5db.codec.WebsocketProtostuffEncoder.java

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/*
 * Copyright 2014 WANdisco
 *
 *  WANdisco 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 c5db.codec;

import c5db.C5ServerConstants;
import c5db.client.generated.Response;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageEncoder;
import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.protostuff.LowCopyProtobufOutput;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.List;

/**
 * A specialized Protostuff encoder used to serialize Protostuff into a WebSocketStream and map them to a Response
 * object. Special care must be paid to handle chunking websocket files transparently for the user.
 */
public class WebsocketProtostuffEncoder extends MessageToMessageEncoder<Response> {

    private static final long MAX_SIZE = C5ServerConstants.MAX_CONTENT_LENGTH_HTTP_AGG;
    private static final Logger LOG = LoggerFactory.getLogger(WebsocketProtostuffEncoder.class);

    @Override
    protected void encode(ChannelHandlerContext channelHandlerContext, Response response, List<Object> objects)
            throws IOException {
        final LowCopyProtobufOutput lcpo = new LowCopyProtobufOutput();
        Response.getSchema().writeTo(lcpo, response);
        final long size = lcpo.buffer.size();

        ByteBuf byteBuf = channelHandlerContext.alloc().buffer((int) size);
        lcpo.buffer.finish().stream().forEach(byteBuf::writeBytes);

        if (size < MAX_SIZE) {
            final BinaryWebSocketFrame frame = new BinaryWebSocketFrame(byteBuf);
            objects.add(frame);
        } else {
            long remaining = size;
            boolean first = true;
            while (remaining > 0) {
                WebSocketFrame frame;
                if (remaining > MAX_SIZE) {
                    final ByteBuf slice = byteBuf.copy((int) (size - remaining), (int) MAX_SIZE);
                    if (first) {
                        frame = new BinaryWebSocketFrame(false, 0, slice);
                        first = false;
                    } else {
                        frame = new ContinuationWebSocketFrame(false, 0, slice);
                    }
                    remaining -= MAX_SIZE;
                } else {
                    frame = new ContinuationWebSocketFrame(true, 0,
                            byteBuf.copy((int) (size - remaining), (int) remaining));
                    remaining = 0;
                }
                objects.add(frame);
            }
        }
    }
}