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Redis Replicator implement Redis Replication protocol written in java.
It can parse,filter,broadcast the RDB and AOF events in a real time manner.
It also can synchronize redis data to your local cache or to database.
/*
* Copyright 2016 leon chen
*
* 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.moilioncircle.redis.replicator.cmd;
import com.moilioncircle.redis.replicator.io.RedisInputStream;
import com.moilioncircle.redis.replicator.util.ByteBuilder;
import java.io.IOException;
import static com.moilioncircle.redis.replicator.Constants.COLON;
import static com.moilioncircle.redis.replicator.Constants.DOLLAR;
import static com.moilioncircle.redis.replicator.Constants.MINUS;
import static com.moilioncircle.redis.replicator.Constants.PLUS;
import static com.moilioncircle.redis.replicator.Constants.STAR;
/**
* @author Leon Chen
* @see protocol
* @since 2.1.0
*/
public class ReplyParser {
private final RedisInputStream in;
public ReplyParser(RedisInputStream in) {
this.in = in;
}
public Object parse() throws IOException {
return parse(new BulkReplyHandler.SimpleBulkReplyHandler(), null);
}
public Object parse(OffsetHandler offsetHandler) throws IOException {
return parse(new BulkReplyHandler.SimpleBulkReplyHandler(), offsetHandler);
}
public Object parse(BulkReplyHandler handler, OffsetHandler offsetHandler) throws IOException {
in.mark();
Object rs = parse(handler);
long len = in.unmark();
if (offsetHandler != null) offsetHandler.handle(len);
return rs;
}
/**
* @param handler bulk reply handler
* @return Object[] or byte[] or Long
* @throws IOException when read timeout
*/
public Object parse(BulkReplyHandler handler) throws IOException {
while (true) {
int c = in.read();
switch (c) {
case DOLLAR:
//RESP Bulk Strings
ByteBuilder builder = ByteBuilder.allocate(128);
while (true) {
while ((c = in.read()) != '\r') {
builder.put((byte) c);
}
if ((c = in.read()) == '\n') {
break;
} else {
builder.put((byte) c);
}
}
String payload = builder.toString();
long len = -1;
// disk-less replication
// $EOF:<40 bytes delimiter>
if (!payload.startsWith("EOF:")) {
len = Long.parseLong(builder.toString());
// $-1\r\n. this is called null string.
// see http://redis.io/topics/protocol
if (len == -1) return null;
} else {
if (handler instanceof BulkReplyHandler.SimpleBulkReplyHandler) {
throw new AssertionError("Parse reply for disk-less replication can not use BulkReplyHandler.SimpleBulkReplyHandler.");
}
}
if (handler != null) return handler.handle(len, in);
throw new AssertionError("Callback is null");
case COLON:
// RESP Integers
builder = ByteBuilder.allocate(128);
while (true) {
while ((c = in.read()) != '\r') {
builder.put((byte) c);
}
if ((c = in.read()) == '\n') {
break;
} else {
builder.put((byte) c);
}
}
//as integer
return Long.parseLong(builder.toString());
case STAR:
// RESP Arrays
builder = ByteBuilder.allocate(128);
while (true) {
while ((c = in.read()) != '\r') {
builder.put((byte) c);
}
if ((c = in.read()) == '\n') {
break;
} else {
builder.put((byte) c);
}
}
len = Long.parseLong(builder.toString());
if (len == -1) return null;
Object[] ary = new Object[(int) len];
for (int i = 0; i < len; i++) {
Object obj = parse(new BulkReplyHandler.SimpleBulkReplyHandler());
ary[i] = obj;
}
return ary;
case PLUS:
// RESP Simple Strings
builder = ByteBuilder.allocate(128);
while (true) {
while ((c = in.read()) != '\r') {
builder.put((byte) c);
}
if ((c = in.read()) == '\n') {
return builder.array();
} else {
builder.put((byte) c);
}
}
case MINUS:
// RESP Errors
builder = ByteBuilder.allocate(128);
while (true) {
while ((c = in.read()) != '\r') {
builder.put((byte) c);
}
if ((c = in.read()) == '\n') {
return builder.array();
} else {
builder.put((byte) c);
}
}
case '\n':
//skip +CONTINUE\r\n[\n]
//skip +FULLRESYNC 8de1787ba490483314a4d30f1c628bc5025eb761 2443808505[\n]$2443808505\r\nxxxxxxxxxxxxxxxx\r\n
//At this stage just a newline works as a PING in order to take the connection live
//bug fix
break;
default:
throw new AssertionError("expect [$,:,*,+,-] but: " + (char) c);
}
}
}
}