| /* |
| * 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.geode.redis.internal.netty; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import io.netty.buffer.ByteBuf; |
| import io.netty.channel.ChannelHandlerContext; |
| import io.netty.handler.codec.ByteToMessageDecoder; |
| |
| import org.apache.geode.redis.internal.statistics.RedisStats; |
| |
| /** |
| * This is the first part of the channel pipeline for Netty. Here incoming bytes are read and a |
| * created {@link Command} is sent down the pipeline. It is unfortunate that this class is not |
| * {@link io.netty.channel.ChannelHandler.Sharable} because no state is kept in this class. State is |
| * kept by {@link ByteToMessageDecoder}, it may be worthwhile to look at a different decoder setup |
| * as to avoid allocating a decoder for every new connection. |
| * <p> |
| * The code flow of the protocol parsing may not be exactly Java like, but this is done very |
| * intentionally. It was found that in cases where large Redis requests are sent that end up being |
| * fragmented, throwing exceptions when the command could not be fully parsed took up an enormous |
| * amount of cpu time. The simplicity of the Redis protocol allows us to just back out and wait for |
| * more data, while exceptions are left to malformed requests which should never happen if using a |
| * proper Redis client. |
| */ |
| public class ByteToCommandDecoder extends ByteToMessageDecoder { |
| |
| /** |
| * Important note |
| * <p> |
| * Do not use '' <-- java primitive chars. Redis uses {@link Coder#CHARSET} encoding so we should |
| * not risk java handling char to byte conversions, rather just hard code {@link Coder#CHARSET} |
| * chars as bytes |
| */ |
| |
| private static final byte rID = 13; // '\r'; |
| private static final byte nID = 10; // '\n'; |
| private static final byte bulkStringID = 36; // '$'; |
| private static final byte arrayID = 42; // '*'; |
| private static final int MAX_BULK_STRING_LENGTH = 512 * 1024 * 1024; // 512 MB |
| |
| private final RedisStats redisStats; |
| |
| public ByteToCommandDecoder(RedisStats redisStats) { |
| this.redisStats = redisStats; |
| } |
| |
| @Override |
| protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception { |
| Command c = null; |
| long bytesRead = 0; |
| do { |
| int startReadIndex = in.readerIndex(); |
| c = parse(in); |
| if (c == null) { |
| in.readerIndex(startReadIndex); |
| break; |
| } |
| bytesRead += in.readerIndex() - startReadIndex; |
| out.add(c); |
| } while (in.isReadable()); // Try to take advantage of pipelining if it is being used |
| redisStats.incNetworkBytesRead(bytesRead); |
| } |
| |
| private Command parse(ByteBuf buffer) throws RedisCommandParserException { |
| if (buffer == null) { |
| throw new NullPointerException(); |
| } |
| if (!buffer.isReadable()) { |
| return null; |
| } |
| |
| byte firstB = buffer.readByte(); |
| if (firstB != arrayID) { |
| throw new RedisCommandParserException( |
| "Expected: " + (char) arrayID + " Actual: " + (char) firstB); |
| } |
| ArrayList<byte[]> commandElems = new ArrayList<byte[]>(); |
| |
| if (!parseArray(commandElems, buffer)) { |
| return null; |
| } |
| |
| return new Command(commandElems); |
| } |
| |
| private boolean parseArray(ArrayList<byte[]> commandElems, ByteBuf buffer) |
| throws RedisCommandParserException { |
| byte currentChar; |
| int arrayLength = parseCurrentNumber(buffer); |
| if (arrayLength == Integer.MIN_VALUE || !parseRN(buffer)) { |
| return false; |
| } |
| if (arrayLength < 0 || arrayLength > 1000000000) { |
| throw new RedisCommandParserException("invalid multibulk length"); |
| } |
| |
| for (int i = 0; i < arrayLength; i++) { |
| if (!buffer.isReadable()) { |
| return false; |
| } |
| currentChar = buffer.readByte(); |
| if (currentChar == bulkStringID) { |
| byte[] newBulkString = parseBulkString(buffer); |
| if (newBulkString == null) { |
| return false; |
| } |
| commandElems.add(newBulkString); |
| } else { |
| throw new RedisCommandParserException( |
| "expected: \'$\', got \'" + (char) currentChar + "\'"); |
| } |
| } |
| return true; |
| } |
| |
| /** |
| * Helper method to parse a bulk string when one is seen |
| * |
| * @param buffer Buffer to read from |
| * @return byte[] representation of the Bulk String read |
| * @throws RedisCommandParserException Thrown when there is illegal syntax |
| */ |
| private byte[] parseBulkString(ByteBuf buffer) throws RedisCommandParserException { |
| int bulkStringLength = parseCurrentNumber(buffer); |
| if (bulkStringLength == Integer.MIN_VALUE) { |
| return null; |
| } |
| if (bulkStringLength > MAX_BULK_STRING_LENGTH) { |
| throw new RedisCommandParserException( |
| "invalid bulk length, cannot exceed max length of " + MAX_BULK_STRING_LENGTH); |
| } |
| if (!parseRN(buffer)) { |
| return null; |
| } |
| |
| if (!buffer.isReadable(bulkStringLength)) { |
| return null; |
| } |
| byte[] bulkString = new byte[bulkStringLength]; |
| buffer.readBytes(bulkString); |
| |
| if (!parseRN(buffer)) { |
| return null; |
| } |
| |
| return bulkString; |
| } |
| |
| /** |
| * Helper method to parse the number at the beginning of the buffer |
| * |
| * @param buffer Buffer to read |
| * @return The number found at the beginning of the buffer |
| */ |
| private int parseCurrentNumber(ByteBuf buffer) { |
| int number = 0; |
| int readerIndex = buffer.readerIndex(); |
| byte b = 0; |
| while (true) { |
| if (!buffer.isReadable()) { |
| return Integer.MIN_VALUE; |
| } |
| b = buffer.readByte(); |
| if (Character.isDigit(b)) { |
| number = number * 10 + (int) (b - '0'); |
| readerIndex++; |
| } else { |
| buffer.readerIndex(readerIndex); |
| break; |
| } |
| } |
| return number; |
| } |
| |
| /** |
| * Helper method that is called when the next characters are supposed to be "\r\n" |
| * |
| * @param buffer Buffer to read from |
| * @throws RedisCommandParserException Thrown when the next two characters are not "\r\n" |
| */ |
| private boolean parseRN(ByteBuf buffer) throws RedisCommandParserException { |
| if (!buffer.isReadable(2)) { |
| return false; |
| } |
| byte b = buffer.readByte(); |
| if (b != rID) { |
| throw new RedisCommandParserException( |
| "expected \'" + (char) rID + "\', got \'" + (char) b + "\'"); |
| } |
| b = buffer.readByte(); |
| if (b != nID) { |
| throw new RedisCommandParserException( |
| "expected: \'" + (char) nID + "\', got \'" + (char) b + "\'"); |
| } |
| return true; |
| } |
| |
| } |