001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.activemq.transport.mqtt; 018 019import java.io.DataInput; 020import java.io.DataInputStream; 021import java.io.DataOutput; 022import java.io.DataOutputStream; 023import java.io.IOException; 024 025import org.apache.activemq.util.ByteArrayInputStream; 026import org.apache.activemq.util.ByteArrayOutputStream; 027import org.apache.activemq.util.ByteSequence; 028import org.apache.activemq.wireformat.WireFormat; 029import org.fusesource.hawtbuf.Buffer; 030import org.fusesource.mqtt.codec.MQTTFrame; 031 032/** 033 * Implements marshalling and unmarsalling the <a 034 * href="http://mqtt.org/">MQTT</a> protocol. 035 */ 036public class MQTTWireFormat implements WireFormat { 037 038 static final int MAX_MESSAGE_LENGTH = 1024 * 1024 * 256; 039 static final long DEFAULT_CONNECTION_TIMEOUT = 30000L; 040 041 private int version = 1; 042 043 private int maxFrameSize = MAX_MESSAGE_LENGTH; 044 private long connectAttemptTimeout = MQTTWireFormat.DEFAULT_CONNECTION_TIMEOUT; 045 046 @Override 047 public ByteSequence marshal(Object command) throws IOException { 048 ByteArrayOutputStream baos = new ByteArrayOutputStream(); 049 DataOutputStream dos = new DataOutputStream(baos); 050 marshal(command, dos); 051 dos.close(); 052 return baos.toByteSequence(); 053 } 054 055 @Override 056 public Object unmarshal(ByteSequence packet) throws IOException { 057 ByteArrayInputStream stream = new ByteArrayInputStream(packet); 058 DataInputStream dis = new DataInputStream(stream); 059 return unmarshal(dis); 060 } 061 062 @Override 063 public void marshal(Object command, DataOutput dataOut) throws IOException { 064 MQTTFrame frame = (MQTTFrame) command; 065 dataOut.write(frame.header()); 066 067 int remaining = 0; 068 for (Buffer buffer : frame.buffers) { 069 remaining += buffer.length; 070 } 071 do { 072 byte digit = (byte) (remaining & 0x7F); 073 remaining >>>= 7; 074 if (remaining > 0) { 075 digit |= 0x80; 076 } 077 dataOut.write(digit); 078 } while (remaining > 0); 079 for (Buffer buffer : frame.buffers) { 080 dataOut.write(buffer.data, buffer.offset, buffer.length); 081 } 082 } 083 084 @Override 085 public Object unmarshal(DataInput dataIn) throws IOException { 086 byte header = dataIn.readByte(); 087 088 byte digit; 089 int multiplier = 1; 090 int length = 0; 091 do { 092 digit = dataIn.readByte(); 093 length += (digit & 0x7F) * multiplier; 094 multiplier <<= 7; 095 } 096 while ((digit & 0x80) != 0); 097 098 if (length >= 0) { 099 if (length > getMaxFrameSize()) { 100 throw new IOException("The maximum message length was exceeded"); 101 } 102 103 if (length > 0) { 104 byte[] data = new byte[length]; 105 dataIn.readFully(data); 106 Buffer body = new Buffer(data); 107 return new MQTTFrame(body).header(header); 108 } else { 109 return new MQTTFrame().header(header); 110 } 111 } 112 return null; 113 } 114 115 /** 116 * @param the version of the wire format 117 */ 118 @Override 119 public void setVersion(int version) { 120 this.version = version; 121 } 122 123 /** 124 * @return the version of the wire format 125 */ 126 @Override 127 public int getVersion() { 128 return this.version; 129 } 130 131 /** 132 * @return the maximum number of bytes a single MQTT message frame is allowed to be. 133 */ 134 public int getMaxFrameSize() { 135 return maxFrameSize; 136 } 137 138 /** 139 * Sets the maximum frame size for an incoming MQTT frame. The protocl limit is 140 * 256 megabytes and this value cannot be set higher. 141 * 142 * @param maxFrameSize 143 * the maximum allowed frame size for a single MQTT frame. 144 */ 145 public void setMaxFrameSize(int maxFrameSize) { 146 this.maxFrameSize = Math.min(MAX_MESSAGE_LENGTH, maxFrameSize); 147 } 148 149 /** 150 * @return the timeout value used to fail a connection if no CONNECT frame read. 151 */ 152 public long getConnectAttemptTimeout() { 153 return connectAttemptTimeout; 154 } 155 156 /** 157 * Sets the timeout value used to fail a connection if no CONNECT frame is read 158 * in the given interval. 159 * 160 * @param connectTimeout 161 * the connection frame received timeout value. 162 */ 163 public void setConnectAttemptTimeout(long connectTimeout) { 164 this.connectAttemptTimeout = connectTimeout; 165 } 166}