/*
* Copyright 2016 The Netty Project
*
* The Netty Project 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 io.netty.handler.codec.redis;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.ByteBufUtil;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.CodecException;
import io.netty.handler.codec.MessageToMessageEncoder;
import io.netty.util.internal.ObjectUtil;
import io.netty.util.internal.UnstableApi;
import java.util.List;
/**
* Encodes {@link RedisMessage} into bytes following
* <a href="http://redis.io/topics/protocol">RESP (REdis Serialization Protocol)</a>.
*/
@UnstableApi
public class RedisEncoder extends MessageToMessageEncoder<RedisMessage> {
private final RedisMessagePool messagePool;
/**
* Creates a new instance with default {@code messagePool}.
*/
public RedisEncoder() {
this(FixedRedisMessagePool.INSTANCE);
}
/**
* Creates a new instance.
* @param messagePool the predefined message pool.
*/
public RedisEncoder(RedisMessagePool messagePool) {
this.messagePool = ObjectUtil.checkNotNull(messagePool, "messagePool");
}
@Override
protected void encode(ChannelHandlerContext ctx, RedisMessage msg, List<Object> out) throws Exception {
try {
writeRedisMessage(ctx.alloc(), msg, out);
} catch (CodecException e) {
throw e;
} catch (Exception e) {
throw new CodecException(e);
}
}
private void writeRedisMessage(ByteBufAllocator allocator, RedisMessage msg, List<Object> out) {
if (msg instanceof SimpleStringRedisMessage) {
writeSimpleStringMessage(allocator, (SimpleStringRedisMessage) msg, out);
} else if (msg instanceof ErrorRedisMessage) {
writeErrorMessage(allocator, (ErrorRedisMessage) msg, out);
} else if (msg instanceof IntegerRedisMessage) {
writeIntegerMessage(allocator, (IntegerRedisMessage) msg, out);
} else if (msg instanceof FullBulkStringRedisMessage) {
writeFullBulkStringMessage(allocator, (FullBulkStringRedisMessage) msg, out);
} else if (msg instanceof BulkStringRedisContent) {
writeBulkStringContent(allocator, (BulkStringRedisContent) msg, out);
} else if (msg instanceof BulkStringHeaderRedisMessage) {
writeBulkStringHeader(allocator, (BulkStringHeaderRedisMessage) msg, out);
} else if (msg instanceof ArrayHeaderRedisMessage) {
writeArrayHeader(allocator, (ArrayHeaderRedisMessage) msg, out);
} else if (msg instanceof ArrayRedisMessage) {
writeArrayMessage(allocator, (ArrayRedisMessage) msg, out);
} else {
throw new CodecException("unknown message type: " + msg);
}
}
private static void writeSimpleStringMessage(ByteBufAllocator allocator, SimpleStringRedisMessage msg,
List<Object> out) {
writeString(allocator, RedisMessageType.SIMPLE_STRING.value(), msg.content(), out);
}
private static void writeErrorMessage(ByteBufAllocator allocator, ErrorRedisMessage msg, List<Object> out) {
writeString(allocator, RedisMessageType.ERROR.value(), msg.content(), out);
}
private static void writeString(ByteBufAllocator allocator, byte type, String content, List<Object> out) {
ByteBuf buf = allocator.ioBuffer(RedisConstants.TYPE_LENGTH + ByteBufUtil.utf8MaxBytes(content) +
RedisConstants.EOL_LENGTH);
buf.writeByte(type);
ByteBufUtil.writeUtf8(buf, content);
buf.writeShort(RedisConstants.EOL_SHORT);
out.add(buf);
}
private void writeIntegerMessage(ByteBufAllocator allocator, IntegerRedisMessage msg, List<Object> out) {
ByteBuf buf = allocator.ioBuffer(RedisConstants.TYPE_LENGTH + RedisConstants.LONG_MAX_LENGTH +
RedisConstants.EOL_LENGTH);
buf.writeByte(RedisMessageType.INTEGER.value());
buf.writeBytes(numberToBytes(msg.value()));
buf.writeShort(RedisConstants.EOL_SHORT);
out.add(buf);
}
private void writeBulkStringHeader(ByteBufAllocator allocator, BulkStringHeaderRedisMessage msg, List<Object> out) {
final ByteBuf buf = allocator.ioBuffer(RedisConstants.TYPE_LENGTH +
(msg.isNull() ? RedisConstants.NULL_LENGTH :
RedisConstants.LONG_MAX_LENGTH + RedisConstants.EOL_LENGTH));
buf.writeByte(RedisMessageType.BULK_STRING.value());
if (msg.isNull()) {
buf.writeShort(RedisConstants.NULL_SHORT);
} else {
buf.writeBytes(numberToBytes(msg.bulkStringLength()));
buf.writeShort(RedisConstants.EOL_SHORT);
}
out.add(buf);
}
private static void writeBulkStringContent(ByteBufAllocator allocator, BulkStringRedisContent msg,
List<Object> out) {
out.add(msg.content().retain());
if (msg instanceof LastBulkStringRedisContent) {
out.add(allocator.ioBuffer(RedisConstants.EOL_LENGTH).writeShort(RedisConstants.EOL_SHORT));
}
}
private void writeFullBulkStringMessage(ByteBufAllocator allocator, FullBulkStringRedisMessage msg,
List<Object> out) {
if (msg.isNull()) {
ByteBuf buf = allocator.ioBuffer(RedisConstants.TYPE_LENGTH + RedisConstants.NULL_LENGTH +
RedisConstants.EOL_LENGTH);
buf.writeByte(RedisMessageType.BULK_STRING.value());
buf.writeShort(RedisConstants.NULL_SHORT);
buf.writeShort(RedisConstants.EOL_SHORT);
out.add(buf);
} else {
ByteBuf headerBuf = allocator.ioBuffer(RedisConstants.TYPE_LENGTH + RedisConstants.LONG_MAX_LENGTH +
RedisConstants.EOL_LENGTH);
headerBuf.writeByte(RedisMessageType.BULK_STRING.value());
headerBuf.writeBytes(numberToBytes(msg.content().readableBytes()));
headerBuf.writeShort(RedisConstants.EOL_SHORT);
out.add(headerBuf);
out.add(msg.content().retain());
out.add(allocator.ioBuffer(RedisConstants.EOL_LENGTH).writeShort(RedisConstants.EOL_SHORT));
}
}
/**
* Write array header only without body. Use this if you want to write arrays as streaming.
*/
private void writeArrayHeader(ByteBufAllocator allocator, ArrayHeaderRedisMessage msg, List<Object> out) {
writeArrayHeader(allocator, msg.isNull(), msg.length(), out);
}
/**
* Write full constructed array message.
*/
private void writeArrayMessage(ByteBufAllocator allocator, ArrayRedisMessage msg, List<Object> out) {
if (msg.isNull()) {
writeArrayHeader(allocator, msg.isNull(), RedisConstants.NULL_VALUE, out);
} else {
writeArrayHeader(allocator, msg.isNull(), msg.children().size(), out);
for (RedisMessage child : msg.children()) {
writeRedisMessage(allocator, child, out);
}
}
}
private void writeArrayHeader(ByteBufAllocator allocator, boolean isNull, long length, List<Object> out) {
if (isNull) {
final ByteBuf buf = allocator.ioBuffer(RedisConstants.TYPE_LENGTH + RedisConstants.NULL_LENGTH +
RedisConstants.EOL_LENGTH);
buf.writeByte(RedisMessageType.ARRAY_HEADER.value());
buf.writeShort(RedisConstants.NULL_SHORT);
buf.writeShort(RedisConstants.EOL_SHORT);
out.add(buf);
} else {
final ByteBuf buf = allocator.ioBuffer(RedisConstants.TYPE_LENGTH + RedisConstants.LONG_MAX_LENGTH +
RedisConstants.EOL_LENGTH);
buf.writeByte(RedisMessageType.ARRAY_HEADER.value());
buf.writeBytes(numberToBytes(length));
buf.writeShort(RedisConstants.EOL_SHORT);
out.add(buf);
}
}
private byte[] numberToBytes(long value) {
byte[] bytes = messagePool.getByteBufOfInteger(value);
return bytes != null ? bytes : RedisCodecUtil.longToAsciiBytes(value);
}
}