Java tutorial
package com.mobius.software.android.iotbroker.mqtt.parser; /** * Mobius Software LTD * Copyright 2015-2016, Mobius Software LTD * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import java.io.UnsupportedEncodingException; import java.util.ArrayList; import java.util.List; import com.mobius.software.android.iotbroker.mqtt.parser.avps.ConnackCode; import com.mobius.software.android.iotbroker.mqtt.parser.avps.LengthDetails; import com.mobius.software.android.iotbroker.mqtt.parser.avps.MessageType; import com.mobius.software.android.iotbroker.mqtt.parser.avps.QoS; import com.mobius.software.android.iotbroker.mqtt.parser.avps.SubackCode; import com.mobius.software.android.iotbroker.mqtt.parser.avps.Text; import com.mobius.software.android.iotbroker.mqtt.parser.avps.Topic; import com.mobius.software.android.iotbroker.mqtt.parser.avps.Will; import com.mobius.software.android.iotbroker.mqtt.parser.exceptions.MalformedMessageException; import com.mobius.software.android.iotbroker.mqtt.parser.header.api.MQMessage; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Connack; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Connect; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Disconnect; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Pingreq; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Pingresp; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Puback; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Pubcomp; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Publish; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Pubrec; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Pubrel; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Suback; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Subscribe; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Unsuback; import com.mobius.software.android.iotbroker.mqtt.parser.header.impl.Unsubscribe; import com.mobius.software.android.iotbroker.mqtt.utility.StringVerifier; public class MQParser { public static ByteBuf next(ByteBuf buf) throws MalformedMessageException { buf.markReaderIndex(); MessageType type = MessageType.valueOf(((buf.readByte() >> 4) & 0xf)); switch (type) { case PINGREQ: case PINGRESP: case DISCONNECT: buf.resetReaderIndex(); return Unpooled.buffer(2); default: LengthDetails length = decodeLength(buf); buf.resetReaderIndex(); if (length.getLength() == 0) return null; int result = length.getLength() + length.getSize() + 1; return result <= buf.readableBytes() ? Unpooled.buffer(result) : null; } } public static MQMessage decode(ByteBuf buf) throws MalformedMessageException, UnsupportedEncodingException { MQMessage header = null; byte fixedHeader = buf.readByte(); LengthDetails length = decodeLength(buf); MessageType type = MessageType.valueOf((fixedHeader >> 4) & 0xf); switch (type) { case CONNECT: byte[] nameValue = new byte[buf.readUnsignedShort()]; buf.readBytes(nameValue, 0, nameValue.length); String name = new String(nameValue, "UTF-8"); if (!name.equals("MQTT")) throw new MalformedMessageException("CONNECT, protocol-name set to " + name); int protocolLevel = buf.readUnsignedByte(); byte contentFlags = buf.readByte(); boolean userNameFlag = (((contentFlags >> 7) & 1) == 1) ? true : false; boolean userPassFlag = (((contentFlags >> 6) & 1) == 1) ? true : false; boolean willRetain = (((contentFlags >> 5) & 1) == 1) ? true : false; QoS willQos = QoS.valueOf(((contentFlags & 0x1f) >> 3) & 3); if (willQos == null) throw new MalformedMessageException("CONNECT, will QoS set to " + willQos); boolean willFlag = (((contentFlags >> 2) & 1) == 1) ? true : false; if (willQos.getValue() > 0 && !willFlag) throw new MalformedMessageException("CONNECT, will QoS set to " + willQos + ", willFlag not set"); if (willRetain && !willFlag) throw new MalformedMessageException("CONNECT, will retain set, willFlag not set"); boolean cleanSession = (((contentFlags >> 1) & 1) == 1) ? true : false; boolean reservedFlag = ((contentFlags & 1) == 1) ? true : false; if (reservedFlag) throw new MalformedMessageException("CONNECT, reserved flag set to true"); int keepalive = buf.readUnsignedShort(); byte[] clientIdValue = new byte[buf.readUnsignedShort()]; buf.readBytes(clientIdValue, 0, clientIdValue.length); String clientID = new String(clientIdValue, "UTF-8"); if (!StringVerifier.verify(clientID)) throw new MalformedMessageException( "ClientID contains restricted characters: U+0000, U+D000-U+DFFF"); Text willTopic = null; byte[] willMessage = null; String username = null; String password = null; Will will = null; if (willFlag) { if (buf.readableBytes() < 2) throw new MalformedMessageException("Invalid encoding will/username/password"); byte[] willTopicValue = new byte[buf.readUnsignedShort()]; if (buf.readableBytes() < willTopicValue.length) throw new MalformedMessageException("Invalid encoding will/username/password"); buf.readBytes(willTopicValue, 0, willTopicValue.length); String willTopicName = new String(willTopicValue, "UTF-8"); if (!StringVerifier.verify(willTopicName)) throw new MalformedMessageException( "WillTopic contains one or more restricted characters: U+0000, U+D000-U+DFFF"); willTopic = new Text(willTopicName); if (buf.readableBytes() < 2) throw new MalformedMessageException("Invalid encoding will/username/password"); willMessage = new byte[buf.readUnsignedShort()]; if (buf.readableBytes() < willMessage.length) throw new MalformedMessageException("Invalid encoding will/username/password"); buf.readBytes(willMessage, 0, willMessage.length); if (willTopic.length() == 0) throw new MalformedMessageException("invalid will encoding"); will = new Will(new Topic(willTopic, willQos), willMessage, willRetain); if (!will.isValid()) throw new MalformedMessageException("invalid will encoding"); } if (userNameFlag) { if (buf.readableBytes() < 2) throw new MalformedMessageException("Invalid encoding will/username/password"); byte[] userNameValue = new byte[buf.readUnsignedShort()]; if (buf.readableBytes() < userNameValue.length) throw new MalformedMessageException("Invalid encoding will/username/password"); buf.readBytes(userNameValue, 0, userNameValue.length); username = new String(userNameValue, "UTF-8"); if (!StringVerifier.verify(username)) throw new MalformedMessageException( "Username contains one or more restricted characters: U+0000, U+D000-U+DFFF"); } if (userPassFlag) { if (buf.readableBytes() < 2) throw new MalformedMessageException("Invalid encoding will/username/password"); byte[] userPassValue = new byte[buf.readUnsignedShort()]; if (buf.readableBytes() < userPassValue.length) throw new MalformedMessageException("Invalid encoding will/username/password"); buf.readBytes(userPassValue, 0, userPassValue.length); password = new String(userPassValue, "UTF-8"); if (!StringVerifier.verify(password)) throw new MalformedMessageException( "Password contains one or more restricted characters: U+0000, U+D000-U+DFFF"); } if (buf.readableBytes() > 0) throw new MalformedMessageException("Invalid encoding will/username/password"); Connect connect = new Connect(username, password, clientID, cleanSession, keepalive, will); if (protocolLevel != 4) connect.setProtocolLevel(protocolLevel); header = connect; break; case CONNACK: byte sessionPresentValue = buf.readByte(); if (sessionPresentValue != 0 && sessionPresentValue != 1) throw new MalformedMessageException( String.format("CONNACK, session-present set to %d", sessionPresentValue & 0xff)); boolean isPresent = sessionPresentValue == 1 ? true : false; short connackByte = buf.readUnsignedByte(); ConnackCode connackCode = ConnackCode.valueOf(connackByte); if (connackCode == null) throw new MalformedMessageException("Invalid connack code: " + connackByte); header = new Connack(isPresent, connackCode); break; case PUBLISH: int dataLength = length.getLength(); fixedHeader &= 0xf; boolean dup = (((fixedHeader >> 3) & 1) == 1) ? true : false; QoS qos = QoS.valueOf((fixedHeader & 0x07) >> 1); if (qos == null) throw new MalformedMessageException("invalid QoS value"); if (dup && qos == QoS.AT_MOST_ONCE) throw new MalformedMessageException("PUBLISH, QoS-0 dup flag present"); boolean retain = ((fixedHeader & 1) == 1) ? true : false; byte[] topicNameValue = new byte[buf.readUnsignedShort()]; buf.readBytes(topicNameValue, 0, topicNameValue.length); String topicName = new String(topicNameValue, "UTF-8"); if (!StringVerifier.verify(topicName)) throw new MalformedMessageException( "Publish-topic contains one or more restricted characters: U+0000, U+D000-U+DFFF"); dataLength -= topicName.length() + 2; Integer packetID = null; if (qos != QoS.AT_MOST_ONCE) { packetID = buf.readUnsignedShort(); if (packetID < 0 || packetID > 65535) throw new MalformedMessageException("Invalid PUBLISH packetID encoding"); dataLength -= 2; } byte[] data = new byte[dataLength]; if (dataLength > 0) buf.readBytes(data, 0, data.length); header = new Publish(packetID, new Topic(new Text(topicName), qos), data, retain, dup); break; case PUBACK: header = new Puback(buf.readUnsignedShort()); break; case PUBREC: header = new Pubrec(buf.readUnsignedShort()); break; case PUBREL: header = new Pubrel(buf.readUnsignedShort()); break; case PUBCOMP: header = new Pubcomp(buf.readUnsignedShort()); break; case SUBSCRIBE: Integer subID = buf.readUnsignedShort(); List<Topic> subscriptions = new ArrayList<Topic>(); while (buf.isReadable()) { byte[] value = new byte[buf.readUnsignedShort()]; buf.readBytes(value, 0, value.length); QoS requestedQos = QoS.valueOf(buf.readByte()); if (requestedQos == null) throw new MalformedMessageException( "Subscribe qos must be in range from 0 to 2: " + requestedQos); String topic = new String(value, "UTF-8"); if (!StringVerifier.verify(topic)) throw new MalformedMessageException( "Subscribe topic contains one or more restricted characters: U+0000, U+D000-U+DFFF"); Topic subscription = new Topic(new Text(topic), requestedQos); subscriptions.add(subscription); } if (subscriptions.isEmpty()) throw new MalformedMessageException("Subscribe with 0 topics"); header = new Subscribe(subID, subscriptions.toArray(new Topic[subscriptions.size()])); break; case SUBACK: Integer subackID = buf.readUnsignedShort(); List<SubackCode> subackCodes = new ArrayList<SubackCode>(); while (buf.isReadable()) { short subackByte = buf.readUnsignedByte(); SubackCode subackCode = SubackCode.valueOf(subackByte); if (subackCode == null) throw new MalformedMessageException("Invalid suback code: " + subackByte); subackCodes.add(subackCode); } if (subackCodes.isEmpty()) throw new MalformedMessageException("Suback with 0 return-codes"); header = new Suback(subackID, subackCodes); break; case UNSUBSCRIBE: Integer unsubID = buf.readUnsignedShort(); List<Topic> unsubscribeTopics = new ArrayList<Topic>(); while (buf.isReadable()) { byte[] value = new byte[buf.readUnsignedShort()]; buf.readBytes(value, 0, value.length); String topic = new String(value, "UTF-8"); if (!StringVerifier.verify(topic)) throw new MalformedMessageException( "Unsubscribe topic contains one or more restricted characters: U+0000, U+D000-U+DFFF"); Topic subscription = new Topic(new Text(topic), QoS.AT_MOST_ONCE); unsubscribeTopics.add(subscription); } if (unsubscribeTopics.isEmpty()) throw new MalformedMessageException("Unsubscribe with 0 topics"); header = new Unsubscribe(unsubID, unsubscribeTopics.toArray(new Topic[unsubscribeTopics.size()])); break; case UNSUBACK: header = new Unsuback(buf.readUnsignedShort()); break; case PINGREQ: header = new Pingreq(); break; case PINGRESP: header = new Pingresp(); break; case DISCONNECT: header = new Disconnect(); break; default: throw new MalformedMessageException("Invalid header type: " + type); } if (buf.isReadable()) throw new MalformedMessageException("unexpected bytes in content"); if (length.getLength() != header.getLength()) throw new MalformedMessageException(String.format("Invalid length. Encoded: %d, actual: %d", length.getLength(), header.getLength())); return header; } public static ByteBuf encode(MQMessage header) throws UnsupportedEncodingException, MalformedMessageException { int length = header.getLength(); ByteBuf buf = getBuffer(length); MessageType type = header.getType(); switch (type) { case CONNECT: Connect connect = (Connect) header; if (connect.isWillFlag() && !connect.getWill().isValid()) throw new MalformedMessageException("invalid will encoding"); buf.setByte(0, (byte) (type.getNum() << 4)); buf.writeShort(4); buf.writeBytes(connect.getName().getBytes()); buf.writeByte(connect.getProtocolLevel()); byte contentFlags = 0; contentFlags |= 0; contentFlags |= connect.isClean() ? 0x02 : 0; contentFlags |= connect.isWillFlag() ? 0x04 : 0; contentFlags |= connect.isWillFlag() ? connect.getWill().getTopic().getQos().getValue() << 3 : 0; contentFlags |= connect.isWillFlag() ? connect.getWill().getRetain() ? 0x20 : 0 : 0; contentFlags |= connect.isUsernameFlag() ? 0x40 : 0; contentFlags |= connect.isPasswordFlag() ? 0x80 : 0; buf.writeByte(contentFlags); buf.writeShort(connect.getKeepAlive()); buf.writeShort(connect.getClientID().length()); buf.writeBytes(connect.getClientID().getBytes("UTF-8")); if (connect.isWillFlag()) { Text willTopic = connect.getWill().getTopic().getName(); if (willTopic != null) { buf.writeShort(willTopic.length()); buf.writeBytes(willTopic.toString().getBytes("UTF-8")); } byte[] willMessage = connect.getWill().getContent(); if (willMessage != null) { buf.writeShort(willMessage.length); buf.writeBytes(willMessage); } } String username = connect.getUserName(); if (username != null) { buf.writeShort(username.length()); buf.writeBytes(username.getBytes("UTF-8")); } String password = connect.getPassword(); if (password != null) { buf.writeShort(password.length()); buf.writeBytes(password.getBytes("UTF-8")); } break; case CONNACK: Connack connack = (Connack) header; buf.setByte(0, (byte) (type.getNum() << 4)); buf.writeBoolean(connack.isSessionPresent()); buf.writeByte(connack.getReturnCode().getNum()); break; case PUBLISH: Publish publish = (Publish) header; byte firstByte = (byte) (type.getNum() << 4); firstByte |= publish.isDup() ? 8 : 0; firstByte |= (publish.getTopic().getQos().getValue() << 1); firstByte |= publish.isRetain() ? 1 : 0; buf.setByte(0, firstByte); buf.writeShort(publish.getTopic().length()); buf.writeBytes(publish.getTopic().getName().toString().getBytes("UTF-8")); if (publish.getPacketID() != null) buf.writeShort(publish.getPacketID()); buf.writeBytes(publish.getContent()); break; case PUBACK: Puback puback = (Puback) header; buf.setByte(0, (byte) (type.getNum() << 4)); buf.writeShort(puback.getPacketID()); break; case PUBREC: Pubrec pubrec = (Pubrec) header; buf.setByte(0, (byte) (type.getNum() << 4)); buf.writeShort(pubrec.getPacketID()); break; case PUBREL: Pubrel pubrel = (Pubrel) header; buf.setByte(0, (byte) ((type.getNum() << 4) | 0x2)); buf.writeShort(pubrel.getPacketID()); break; case PUBCOMP: Pubcomp pubcomp = (Pubcomp) header; buf.setByte(0, (byte) (type.getNum() << 4)); buf.writeShort(pubcomp.getPacketID()); break; case SUBSCRIBE: Subscribe sub = (Subscribe) header; buf.setByte(0, (byte) ((type.getNum() << 4) | 0x2)); if (sub.getPacketID() != null) buf.writeShort(sub.getPacketID()); for (Topic subscription : sub.getTopics()) { buf.writeShort(subscription.getName().length()); buf.writeBytes(subscription.getName().toString().getBytes("UTF-8")); buf.writeByte(subscription.getQos().getValue()); } break; case SUBACK: Suback suback = (Suback) header; buf.setByte(0, (byte) (type.getNum() << 4)); buf.writeShort(suback.getPacketID()); for (SubackCode code : suback.getReturnCodes()) buf.writeByte(code.getNum()); break; case UNSUBSCRIBE: Unsubscribe unsub = (Unsubscribe) header; buf.setByte(0, (byte) ((type.getNum() << 4) | 0x2)); buf.writeShort(unsub.getPacketID()); for (Topic topic : unsub.getTopics()) { buf.writeShort(topic.getName().length()); buf.writeBytes(topic.getName().toString().getBytes("UTF-8")); } break; case UNSUBACK: Unsuback unsuback = (Unsuback) header; buf.setByte(0, (byte) (type.getNum() << 4)); buf.writeShort(unsuback.getPacketID()); break; case DISCONNECT: case PINGREQ: case PINGRESP: buf.setByte(0, (byte) (type.getNum() << 4)); break; default: throw new MalformedMessageException("Invalid header type: " + type); } return buf; } private static ByteBuf getBuffer(final int length) throws MalformedMessageException { byte[] lengthBytes; if (length <= 127) lengthBytes = new byte[1]; else if (length <= 16383) lengthBytes = new byte[2]; else if (length <= 2097151) lengthBytes = new byte[3]; else if (length <= 26843545) lengthBytes = new byte[4]; else throw new MalformedMessageException("header length exceeds maximum of 26843545 bytes"); byte encByte; int pos = 0, l = length; do { encByte = (byte) (l % 128); l /= 128; if (l > 0) lengthBytes[pos++] = (byte) (encByte | 128); else lengthBytes[pos++] = encByte; } while (l > 0); int bufferSize = 1 + lengthBytes.length + length; ByteBuf buf = Unpooled.buffer(bufferSize); buf.writeByte(0); buf.writeBytes(lengthBytes); return buf; } private static LengthDetails decodeLength(ByteBuf buf) throws MalformedMessageException { int length = 0, multiplier = 1; int bytesUsed = 0; byte enc = 0; do { if (multiplier > 128 * 128 * 128) throw new MalformedMessageException("Encoded length exceeds maximum of 268435455 bytes"); if (!buf.isReadable()) return new LengthDetails(0, 0); enc = buf.readByte(); length += (enc & 0x7f) * multiplier; multiplier *= 128; bytesUsed++; } while ((enc & 0x80) != 0); return new LengthDetails(length, bytesUsed); } }