io.netty.handler.codec.mqtt.MqttCodecUtil Maven / Gradle / Ivy
/*
* 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.handler.codec.DecoderException;
final class MqttCodecUtil {
private static final char[] TOPIC_WILDCARDS = {'#', '+'};
private static final int MIN_CLIENT_ID_LENGTH = 1;
private static final int MAX_CLIENT_ID_LENGTH = 23;
static boolean isValidPublishTopicName(String topicName) {
// publish topic name must not contain any wildcard
for (char c : TOPIC_WILDCARDS) {
if (topicName.indexOf(c) >= 0) {
return false;
}
}
return true;
}
static boolean isValidMessageId(int messageId) {
return messageId != 0;
}
static boolean isValidClientId(MqttVersion mqttVersion, String clientId) {
if (mqttVersion == MqttVersion.MQTT_3_1) {
return clientId != null && clientId.length() >= MIN_CLIENT_ID_LENGTH &&
clientId.length() <= MAX_CLIENT_ID_LENGTH;
} else if (mqttVersion == MqttVersion.MQTT_3_1_1) {
// In 3.1.3.1 Client Identifier of MQTT 3.1.1 specification, The Server MAY allow ClientId’s
// that contain more than 23 encoded bytes. And, The Server MAY allow zero-length ClientId.
return clientId != null;
}
throw new IllegalArgumentException(mqttVersion + " is unknown mqtt version");
}
static MqttFixedHeader validateFixedHeader(MqttFixedHeader mqttFixedHeader) {
switch (mqttFixedHeader.messageType()) {
case PUBREL:
case SUBSCRIBE:
case UNSUBSCRIBE:
if (mqttFixedHeader.qosLevel() != MqttQoS.AT_LEAST_ONCE) {
throw new DecoderException(mqttFixedHeader.messageType().name() + " message must have QoS 1");
}
default:
return mqttFixedHeader;
}
}
static MqttFixedHeader resetUnusedFields(MqttFixedHeader mqttFixedHeader) {
switch (mqttFixedHeader.messageType()) {
case CONNECT:
case CONNACK:
case PUBACK:
case PUBREC:
case PUBCOMP:
case SUBACK:
case UNSUBACK:
case PINGREQ:
case PINGRESP:
case DISCONNECT:
if (mqttFixedHeader.isDup() ||
mqttFixedHeader.qosLevel() != MqttQoS.AT_MOST_ONCE ||
mqttFixedHeader.isRetain()) {
return new MqttFixedHeader(
mqttFixedHeader.messageType(),
false,
MqttQoS.AT_MOST_ONCE,
false,
mqttFixedHeader.remainingLength());
}
return mqttFixedHeader;
case PUBREL:
case SUBSCRIBE:
case UNSUBSCRIBE:
if (mqttFixedHeader.isRetain()) {
return new MqttFixedHeader(
mqttFixedHeader.messageType(),
mqttFixedHeader.isDup(),
mqttFixedHeader.qosLevel(),
false,
mqttFixedHeader.remainingLength());
}
return mqttFixedHeader;
default:
return mqttFixedHeader;
}
}
private MqttCodecUtil() { }
}