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io.netty.handler.codec.mqtt.MqttEncoder Maven / Gradle / Ivy
This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including
all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and
Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* Copyright 2014 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.mqtt;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.DecoderException;
import io.netty.handler.codec.MessageToMessageEncoder;
import io.netty.util.CharsetUtil;
import io.netty.util.internal.EmptyArrays;
import java.util.List;
import static io.netty.handler.codec.mqtt.MqttCodecUtil.*;
/**
* Encodes Mqtt messages into bytes following the protocol specification v3.1
* as described here MQTTV3.1
*/
@ChannelHandler.Sharable
public final class MqttEncoder extends MessageToMessageEncoder {
public static final MqttEncoder INSTANCE = new MqttEncoder();
private MqttEncoder() { }
@Override
protected void encode(ChannelHandlerContext ctx, MqttMessage msg, List out) throws Exception {
out.add(doEncode(ctx.alloc(), msg));
}
/**
* This is the main encoding method.
* It's only visible for testing.
*
* @param byteBufAllocator Allocates ByteBuf
* @param message MQTT message to encode
* @return ByteBuf with encoded bytes
*/
static ByteBuf doEncode(ByteBufAllocator byteBufAllocator, MqttMessage message) {
switch (message.fixedHeader().messageType()) {
case CONNECT:
return encodeConnectMessage(byteBufAllocator, (MqttConnectMessage) message);
case CONNACK:
return encodeConnAckMessage(byteBufAllocator, (MqttConnAckMessage) message);
case PUBLISH:
return encodePublishMessage(byteBufAllocator, (MqttPublishMessage) message);
case SUBSCRIBE:
return encodeSubscribeMessage(byteBufAllocator, (MqttSubscribeMessage) message);
case UNSUBSCRIBE:
return encodeUnsubscribeMessage(byteBufAllocator, (MqttUnsubscribeMessage) message);
case SUBACK:
return encodeSubAckMessage(byteBufAllocator, (MqttSubAckMessage) message);
case UNSUBACK:
case PUBACK:
case PUBREC:
case PUBREL:
case PUBCOMP:
return encodeMessageWithOnlySingleByteFixedHeaderAndMessageId(byteBufAllocator, message);
case PINGREQ:
case PINGRESP:
case DISCONNECT:
return encodeMessageWithOnlySingleByteFixedHeader(byteBufAllocator, message);
default:
throw new IllegalArgumentException(
"Unknown message type: " + message.fixedHeader().messageType().value());
}
}
private static ByteBuf encodeConnectMessage(
ByteBufAllocator byteBufAllocator,
MqttConnectMessage message) {
int payloadBufferSize = 0;
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttConnectVariableHeader variableHeader = message.variableHeader();
MqttConnectPayload payload = message.payload();
MqttVersion mqttVersion = MqttVersion.fromProtocolNameAndLevel(variableHeader.name(),
(byte) variableHeader.version());
// as MQTT 3.1 & 3.1.1 spec, If the User Name Flag is set to 0, the Password Flag MUST be set to 0
if (!variableHeader.hasUserName() && variableHeader.hasPassword()) {
throw new DecoderException("Without a username, the password MUST be not set");
}
// Client id
String clientIdentifier = payload.clientIdentifier();
if (!isValidClientId(mqttVersion, clientIdentifier)) {
throw new MqttIdentifierRejectedException("invalid clientIdentifier: " + clientIdentifier);
}
byte[] clientIdentifierBytes = encodeStringUtf8(clientIdentifier);
payloadBufferSize += 2 + clientIdentifierBytes.length;
// Will topic and message
String willTopic = payload.willTopic();
byte[] willTopicBytes = willTopic != null ? encodeStringUtf8(willTopic) : EmptyArrays.EMPTY_BYTES;
byte[] willMessage = payload.willMessageInBytes();
byte[] willMessageBytes = willMessage != null ? willMessage : EmptyArrays.EMPTY_BYTES;
if (variableHeader.isWillFlag()) {
payloadBufferSize += 2 + willTopicBytes.length;
payloadBufferSize += 2 + willMessageBytes.length;
}
String userName = payload.userName();
byte[] userNameBytes = userName != null ? encodeStringUtf8(userName) : EmptyArrays.EMPTY_BYTES;
if (variableHeader.hasUserName()) {
payloadBufferSize += 2 + userNameBytes.length;
}
byte[] password = payload.passwordInBytes();
byte[] passwordBytes = password != null ? password : EmptyArrays.EMPTY_BYTES;
if (variableHeader.hasPassword()) {
payloadBufferSize += 2 + passwordBytes.length;
}
// Fixed header
byte[] protocolNameBytes = mqttVersion.protocolNameBytes();
int variableHeaderBufferSize = 2 + protocolNameBytes.length + 4;
int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variablePartSize);
buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variablePartSize);
buf.writeShort(protocolNameBytes.length);
buf.writeBytes(protocolNameBytes);
buf.writeByte(variableHeader.version());
buf.writeByte(getConnVariableHeaderFlag(variableHeader));
buf.writeShort(variableHeader.keepAliveTimeSeconds());
// Payload
buf.writeShort(clientIdentifierBytes.length);
buf.writeBytes(clientIdentifierBytes, 0, clientIdentifierBytes.length);
if (variableHeader.isWillFlag()) {
buf.writeShort(willTopicBytes.length);
buf.writeBytes(willTopicBytes, 0, willTopicBytes.length);
buf.writeShort(willMessageBytes.length);
buf.writeBytes(willMessageBytes, 0, willMessageBytes.length);
}
if (variableHeader.hasUserName()) {
buf.writeShort(userNameBytes.length);
buf.writeBytes(userNameBytes, 0, userNameBytes.length);
}
if (variableHeader.hasPassword()) {
buf.writeShort(passwordBytes.length);
buf.writeBytes(passwordBytes, 0, passwordBytes.length);
}
return buf;
}
private static int getConnVariableHeaderFlag(MqttConnectVariableHeader variableHeader) {
int flagByte = 0;
if (variableHeader.hasUserName()) {
flagByte |= 0x80;
}
if (variableHeader.hasPassword()) {
flagByte |= 0x40;
}
if (variableHeader.isWillRetain()) {
flagByte |= 0x20;
}
flagByte |= (variableHeader.willQos() & 0x03) << 3;
if (variableHeader.isWillFlag()) {
flagByte |= 0x04;
}
if (variableHeader.isCleanSession()) {
flagByte |= 0x02;
}
return flagByte;
}
private static ByteBuf encodeConnAckMessage(
ByteBufAllocator byteBufAllocator,
MqttConnAckMessage message) {
ByteBuf buf = byteBufAllocator.buffer(4);
buf.writeByte(getFixedHeaderByte1(message.fixedHeader()));
buf.writeByte(2);
buf.writeByte(message.variableHeader().isSessionPresent() ? 0x01 : 0x00);
buf.writeByte(message.variableHeader().connectReturnCode().byteValue());
return buf;
}
private static ByteBuf encodeSubscribeMessage(
ByteBufAllocator byteBufAllocator,
MqttSubscribeMessage message) {
int variableHeaderBufferSize = 2;
int payloadBufferSize = 0;
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttMessageIdVariableHeader variableHeader = message.variableHeader();
MqttSubscribePayload payload = message.payload();
for (MqttTopicSubscription topic : payload.topicSubscriptions()) {
String topicName = topic.topicName();
byte[] topicNameBytes = encodeStringUtf8(topicName);
payloadBufferSize += 2 + topicNameBytes.length;
payloadBufferSize += 1;
}
int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variablePartSize);
buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variablePartSize);
// Variable Header
int messageId = variableHeader.messageId();
buf.writeShort(messageId);
// Payload
for (MqttTopicSubscription topic : payload.topicSubscriptions()) {
String topicName = topic.topicName();
byte[] topicNameBytes = encodeStringUtf8(topicName);
buf.writeShort(topicNameBytes.length);
buf.writeBytes(topicNameBytes, 0, topicNameBytes.length);
buf.writeByte(topic.qualityOfService().value());
}
return buf;
}
private static ByteBuf encodeUnsubscribeMessage(
ByteBufAllocator byteBufAllocator,
MqttUnsubscribeMessage message) {
int variableHeaderBufferSize = 2;
int payloadBufferSize = 0;
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttMessageIdVariableHeader variableHeader = message.variableHeader();
MqttUnsubscribePayload payload = message.payload();
for (String topicName : payload.topics()) {
byte[] topicNameBytes = encodeStringUtf8(topicName);
payloadBufferSize += 2 + topicNameBytes.length;
}
int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variablePartSize);
buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variablePartSize);
// Variable Header
int messageId = variableHeader.messageId();
buf.writeShort(messageId);
// Payload
for (String topicName : payload.topics()) {
byte[] topicNameBytes = encodeStringUtf8(topicName);
buf.writeShort(topicNameBytes.length);
buf.writeBytes(topicNameBytes, 0, topicNameBytes.length);
}
return buf;
}
private static ByteBuf encodeSubAckMessage(
ByteBufAllocator byteBufAllocator,
MqttSubAckMessage message) {
int variableHeaderBufferSize = 2;
int payloadBufferSize = message.payload().grantedQoSLevels().size();
int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variablePartSize);
buf.writeByte(getFixedHeaderByte1(message.fixedHeader()));
writeVariableLengthInt(buf, variablePartSize);
buf.writeShort(message.variableHeader().messageId());
for (int qos : message.payload().grantedQoSLevels()) {
buf.writeByte(qos);
}
return buf;
}
private static ByteBuf encodePublishMessage(
ByteBufAllocator byteBufAllocator,
MqttPublishMessage message) {
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttPublishVariableHeader variableHeader = message.variableHeader();
ByteBuf payload = message.payload().duplicate();
String topicName = variableHeader.topicName();
byte[] topicNameBytes = encodeStringUtf8(topicName);
int variableHeaderBufferSize = 2 + topicNameBytes.length +
(mqttFixedHeader.qosLevel().value() > 0 ? 2 : 0);
int payloadBufferSize = payload.readableBytes();
int variablePartSize = variableHeaderBufferSize + payloadBufferSize;
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variablePartSize);
ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variablePartSize);
buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variablePartSize);
buf.writeShort(topicNameBytes.length);
buf.writeBytes(topicNameBytes);
if (mqttFixedHeader.qosLevel().value() > 0) {
buf.writeShort(variableHeader.messageId());
}
buf.writeBytes(payload);
return buf;
}
private static ByteBuf encodeMessageWithOnlySingleByteFixedHeaderAndMessageId(
ByteBufAllocator byteBufAllocator,
MqttMessage message) {
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
MqttMessageIdVariableHeader variableHeader = (MqttMessageIdVariableHeader) message.variableHeader();
int msgId = variableHeader.messageId();
int variableHeaderBufferSize = 2; // variable part only has a message id
int fixedHeaderBufferSize = 1 + getVariableLengthInt(variableHeaderBufferSize);
ByteBuf buf = byteBufAllocator.buffer(fixedHeaderBufferSize + variableHeaderBufferSize);
buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
writeVariableLengthInt(buf, variableHeaderBufferSize);
buf.writeShort(msgId);
return buf;
}
private static ByteBuf encodeMessageWithOnlySingleByteFixedHeader(
ByteBufAllocator byteBufAllocator,
MqttMessage message) {
MqttFixedHeader mqttFixedHeader = message.fixedHeader();
ByteBuf buf = byteBufAllocator.buffer(2);
buf.writeByte(getFixedHeaderByte1(mqttFixedHeader));
buf.writeByte(0);
return buf;
}
private static int getFixedHeaderByte1(MqttFixedHeader header) {
int ret = 0;
ret |= header.messageType().value() << 4;
if (header.isDup()) {
ret |= 0x08;
}
ret |= header.qosLevel().value() << 1;
if (header.isRetain()) {
ret |= 0x01;
}
return ret;
}
private static void writeVariableLengthInt(ByteBuf buf, int num) {
do {
int digit = num % 128;
num /= 128;
if (num > 0) {
digit |= 0x80;
}
buf.writeByte(digit);
} while (num > 0);
}
private static int getVariableLengthInt(int num) {
int count = 0;
do {
num /= 128;
count++;
} while (num > 0);
return count;
}
private static byte[] encodeStringUtf8(String s) {
return s.getBytes(CharsetUtil.UTF_8);
}
}
