Diff: Milkcocoa/MQTT/MQTTClient.h

Revision:

24:6ba1245bf049

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Milkcocoa/MQTT/MQTTClient.h	Tue Jan 24 13:41:36 2017 +0000
@@ -0,0 +1,940 @@
+/*******************************************************************************
+ * Copyright (c) 2014, 2015 IBM Corp.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * and Eclipse Distribution License v1.0 which accompany this distribution.
+ *
+ * The Eclipse Public License is available at
+ *    http://www.eclipse.org/legal/epl-v10.html
+ * and the Eclipse Distribution License is available at
+ *   http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * Contributors:
+ *    Ian Craggs - initial API and implementation and/or initial documentation
+ *    Ian Craggs - fix for bug 458512 - QoS 2 messages
+ *    Ian Craggs - fix for bug 460389 - send loop uses wrong length
+ *    Ian Craggs - fix for bug 464169 - clearing subscriptions
+ *    Ian Craggs - fix for bug 464551 - enums and ints can be different size
+ *******************************************************************************/
+
+#if !defined(MQTTCLIENT_H)
+#define MQTTCLIENT_H
+
+#include "FP.h"
+#include "MQTTPacket.h"
+#include "stdio.h"
+#include "MQTTLogging.h"
+
+#if !defined(MQTTCLIENT_QOS1)
+    #define MQTTCLIENT_QOS1 1
+#endif
+#if !defined(MQTTCLIENT_QOS2)
+    #define MQTTCLIENT_QOS2 0
+#endif
+
+namespace MQTT
+{
+
+
+enum QoS { QOS0, QOS1, QOS2 };
+
+// all failure return codes must be negative
+enum returnCode { BUFFER_OVERFLOW = -2, FAILURE = -1, SUCCESS = 0 };
+
+
+struct Message
+{
+    enum QoS qos;
+    bool retained;
+    bool dup;
+    unsigned short id;
+    void *payload;
+    size_t payloadlen;
+};
+
+
+struct MessageData
+{
+    MessageData(MQTTString &aTopicName, struct Message &aMessage)  : message(aMessage), topicName(aTopicName)
+    { }
+
+    struct Message &message;
+    MQTTString &topicName;
+};
+
+
+class PacketId
+{
+public:
+    PacketId()
+    {
+        next = 0;
+    }
+
+    int getNext()
+    {
+        return next = (next == MAX_PACKET_ID) ? 1 : ++next;
+    }
+
+private:
+    static const int MAX_PACKET_ID = 65535;
+    int next;
+};
+
+
+/**
+ * @class Client
+ * @brief blocking, non-threaded MQTT client API
+ *
+ * This version of the API blocks on all method calls, until they are complete.  This means that only one
+ * MQTT request can be in process at any one time.
+ * @param Network a network class which supports send, receive
+ * @param Timer a timer class with the methods:
+ */
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE = 100, int MAX_MESSAGE_HANDLERS = 5>
+class Client
+{
+
+public:
+
+    typedef void (*messageHandler)(MessageData&);
+
+    /** Construct the client
+     *  @param network - pointer to an instance of the Network class - must be connected to the endpoint
+     *      before calling MQTT connect
+     *  @param limits an instance of the Limit class - to alter limits as required
+     */
+    Client(Network& network, unsigned int command_timeout_ms = 30000);
+
+    /** Set the default message handling callback - used for any message which does not match a subscription message handler
+     *  @param mh - pointer to the callback function
+     */
+    void setDefaultMessageHandler(messageHandler mh)
+    {
+        defaultMessageHandler.attach(mh);
+    }
+
+    /** MQTT Connect - send an MQTT connect packet down the network and wait for a Connack
+     *  The nework object must be connected to the network endpoint before calling this
+     *  Default connect options are used
+     *  @return success code -
+     */
+    int connect();
+    
+        /** MQTT Connect - send an MQTT connect packet down the network and wait for a Connack
+     *  The nework object must be connected to the network endpoint before calling this
+     *  @param options - connect options
+     *  @return success code -
+     */
+    int connect(MQTTPacket_connectData& options);
+
+    /** MQTT Publish - send an MQTT publish packet and wait for all acks to complete for all QoSs
+     *  @param topic - the topic to publish to
+     *  @param message - the message to send
+     *  @return success code -
+     */
+    int publish(const char* topicName, Message& message);
+    
+    /** MQTT Publish - send an MQTT publish packet and wait for all acks to complete for all QoSs
+     *  @param topic - the topic to publish to
+     *  @param payload - the data to send
+     *  @param payloadlen - the length of the data
+     *  @param qos - the QoS to send the publish at
+     *  @param retained - whether the message should be retained
+     *  @return success code -
+     */
+    int publish(const char* topicName, void* payload, size_t payloadlen, enum QoS qos = QOS0, bool retained = false);
+    
+    /** MQTT Publish - send an MQTT publish packet and wait for all acks to complete for all QoSs
+     *  @param topic - the topic to publish to
+     *  @param payload - the data to send
+     *  @param payloadlen - the length of the data
+     *  @param id - the packet id used - returned 
+     *  @param qos - the QoS to send the publish at
+     *  @param retained - whether the message should be retained
+     *  @return success code -
+     */
+    int publish(const char* topicName, void* payload, size_t payloadlen, unsigned short& id, enum QoS qos = QOS1, bool retained = false);
+
+    /** MQTT Subscribe - send an MQTT subscribe packet and wait for the suback
+     *  @param topicFilter - a topic pattern which can include wildcards
+     *  @param qos - the MQTT QoS to subscribe at
+     *  @param mh - the callback function to be invoked when a message is received for this subscription
+     *  @return success code -
+     */
+    int subscribe(const char* topicFilter, enum QoS qos, messageHandler mh);
+
+    /** MQTT Unsubscribe - send an MQTT unsubscribe packet and wait for the unsuback
+     *  @param topicFilter - a topic pattern which can include wildcards
+     *  @return success code -
+     */
+    int unsubscribe(const char* topicFilter);
+
+    /** MQTT Disconnect - send an MQTT disconnect packet, and clean up any state
+     *  @return success code -
+     */
+    int disconnect();
+
+    /** A call to this API must be made within the keepAlive interval to keep the MQTT connection alive
+     *  yield can be called if no other MQTT operation is needed.  This will also allow messages to be
+     *  received.
+     *  @param timeout_ms the time to wait, in milliseconds
+     *  @return success code - on failure, this means the client has disconnected
+     */
+    int yield(unsigned long timeout_ms = 1000L);
+
+    /** Is the client connected?
+     *  @return flag - is the client connected or not?
+     */
+    bool isConnected()
+    {
+        return isconnected;
+    }
+
+private:
+
+    void cleanSession();
+    int cycle(Timer& timer);
+    int waitfor(int packet_type, Timer& timer);
+    int keepalive();
+    int publish(int len, Timer& timer, enum QoS qos);
+
+    int decodePacket(int* value, int timeout);
+    int readPacket(Timer& timer);
+    int sendPacket(int length, Timer& timer);
+    int deliverMessage(MQTTString& topicName, Message& message);
+    bool isTopicMatched(char* topicFilter, MQTTString& topicName);
+
+    Network& ipstack;
+    unsigned long command_timeout_ms;
+
+    unsigned char sendbuf[MAX_MQTT_PACKET_SIZE];
+    unsigned char readbuf[MAX_MQTT_PACKET_SIZE];
+
+    Timer last_sent, last_received;
+    unsigned int keepAliveInterval;
+    bool ping_outstanding;
+    bool cleansession;
+
+    PacketId packetid;
+
+    struct MessageHandlers
+    {
+        const char* topicFilter;
+        FP<void, MessageData&> fp;
+    } messageHandlers[MAX_MESSAGE_HANDLERS];      // Message handlers are indexed by subscription topic
+
+    FP<void, MessageData&> defaultMessageHandler;
+
+    bool isconnected;
+
+#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
+    unsigned char pubbuf[MAX_MQTT_PACKET_SIZE];  // store the last publish for sending on reconnect
+    int inflightLen;
+    unsigned short inflightMsgid;
+    enum QoS inflightQoS;
+#endif
+
+#if MQTTCLIENT_QOS2
+    bool pubrel;
+    #if !defined(MAX_INCOMING_QOS2_MESSAGES)
+        #define MAX_INCOMING_QOS2_MESSAGES 10
+    #endif
+    unsigned short incomingQoS2messages[MAX_INCOMING_QOS2_MESSAGES];
+    bool isQoS2msgidFree(unsigned short id);
+    bool useQoS2msgid(unsigned short id);
+    void freeQoS2msgid(unsigned short id);
+#endif
+
+};
+
+}
+
+
+template<class Network, class Timer, int a, int MAX_MESSAGE_HANDLERS>
+void MQTT::Client<Network, Timer, a, MAX_MESSAGE_HANDLERS>::cleanSession() 
+{
+    ping_outstanding = false;
+    for (int i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
+        messageHandlers[i].topicFilter = 0;
+    isconnected = false;
+
+#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
+    inflightMsgid = 0;
+    inflightQoS = QOS0;
+#endif
+
+#if MQTTCLIENT_QOS2
+    pubrel = false;
+    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
+        incomingQoS2messages[i] = 0;
+#endif
+}
+
+
+template<class Network, class Timer, int a, int MAX_MESSAGE_HANDLERS>
+MQTT::Client<Network, Timer, a, MAX_MESSAGE_HANDLERS>::Client(Network& network, unsigned int command_timeout_ms)  : ipstack(network), packetid()
+{
+    last_sent = Timer();
+    last_received = Timer();
+    this->command_timeout_ms = command_timeout_ms;
+    cleanSession();
+}
+
+
+#if MQTTCLIENT_QOS2
+template<class Network, class Timer, int a, int b>
+bool MQTT::Client<Network, Timer, a, b>::isQoS2msgidFree(unsigned short id)
+{
+    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
+    {
+        if (incomingQoS2messages[i] == id)
+            return false;
+    }
+    return true;
+}
+
+
+template<class Network, class Timer, int a, int b>
+bool MQTT::Client<Network, Timer, a, b>::useQoS2msgid(unsigned short id)
+{
+    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
+    {
+        if (incomingQoS2messages[i] == 0)
+        {
+            incomingQoS2messages[i] = id;
+            return true;
+        }
+    }
+    return false;
+}
+
+
+template<class Network, class Timer, int a, int b>
+void MQTT::Client<Network, Timer, a, b>::freeQoS2msgid(unsigned short id)
+{
+    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
+    {
+        if (incomingQoS2messages[i] == id)
+        {
+            incomingQoS2messages[i] = 0;
+            return;
+        }
+    }
+}
+#endif
+
+
+template<class Network, class Timer, int a, int b>
+int MQTT::Client<Network, Timer, a, b>::sendPacket(int length, Timer& timer)
+{
+    int rc = FAILURE,
+        sent = 0;
+
+    while (sent < length && !timer.expired())
+    {
+        rc = ipstack.write(&sendbuf[sent], length - sent, timer.left_ms());
+        if (rc < 0)  // there was an error writing the data
+            break;
+        sent += rc;
+    }
+    if (sent == length)
+    {
+        if (this->keepAliveInterval > 0)
+            last_sent.countdown(this->keepAliveInterval); // record the fact that we have successfully sent the packet
+        rc = SUCCESS;
+    }
+    else
+        rc = FAILURE;
+        
+#if defined(MQTT_DEBUG)
+    char printbuf[150];
+    DEBUG("Rc %d from sending packet %s\n", rc, MQTTFormat_toServerString(printbuf, sizeof(printbuf), sendbuf, length));
+#endif
+    return rc;
+}
+
+
+template<class Network, class Timer, int a, int b>
+int MQTT::Client<Network, Timer, a, b>::decodePacket(int* value, int timeout)
+{
+    unsigned char c;
+    int multiplier = 1;
+    int len = 0;
+    const int MAX_NO_OF_REMAINING_LENGTH_BYTES = 4;
+
+    *value = 0;
+    do
+    {
+        int rc = MQTTPACKET_READ_ERROR;
+
+        if (++len > MAX_NO_OF_REMAINING_LENGTH_BYTES)
+        {
+            rc = MQTTPACKET_READ_ERROR; /* bad data */
+            goto exit;
+        }
+        rc = ipstack.read(&c, 1, timeout);
+        if (rc != 1)
+            goto exit;
+        *value += (c & 127) * multiplier;
+        multiplier *= 128;
+    } while ((c & 128) != 0);
+exit:
+    return len;
+}
+
+
+/**
+ * If any read fails in this method, then we should disconnect from the network, as on reconnect
+ * the packets can be retried.
+ * @param timeout the max time to wait for the packet read to complete, in milliseconds
+ * @return the MQTT packet type, or -1 if none
+ */
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::readPacket(Timer& timer)
+{
+    int rc = FAILURE;
+    MQTTHeader header = {0};
+    int len = 0;
+    int rem_len = 0;
+
+    /* 1. read the header byte.  This has the packet type in it */
+    if (ipstack.read(readbuf, 1, timer.left_ms()) != 1)
+        goto exit;
+
+    len = 1;
+    /* 2. read the remaining length.  This is variable in itself */
+    decodePacket(&rem_len, timer.left_ms());
+    len += MQTTPacket_encode(readbuf + 1, rem_len); /* put the original remaining length into the buffer */
+
+    if (rem_len > (MAX_MQTT_PACKET_SIZE - len))
+    {
+        rc = BUFFER_OVERFLOW;
+        goto exit;
+    }
+
+    /* 3. read the rest of the buffer using a callback to supply the rest of the data */
+    if (rem_len > 0 && (ipstack.read(readbuf + len, rem_len, timer.left_ms()) != rem_len))
+        goto exit;
+
+    header.byte = readbuf[0];
+    rc = header.bits.type;
+    if (this->keepAliveInterval > 0)
+        last_received.countdown(this->keepAliveInterval); // record the fact that we have successfully received a packet
+exit:
+        
+#if defined(MQTT_DEBUG)
+    if (rc >= 0)
+    {
+        char printbuf[50];
+        DEBUG("Rc %d from receiving packet %s\n", rc, MQTTFormat_toClientString(printbuf, sizeof(printbuf), readbuf, len));
+    }
+#endif
+    return rc;
+}
+
+
+// assume topic filter and name is in correct format
+// # can only be at end
+// + and # can only be next to separator
+template<class Network, class Timer, int a, int b>
+bool MQTT::Client<Network, Timer, a, b>::isTopicMatched(char* topicFilter, MQTTString& topicName)
+{
+    char* curf = topicFilter;
+    char* curn = topicName.lenstring.data;
+    char* curn_end = curn + topicName.lenstring.len;
+
+    while (*curf && curn < curn_end)
+    {
+        if (*curn == '/' && *curf != '/')
+            break;
+        if (*curf != '+' && *curf != '#' && *curf != *curn)
+            break;
+        if (*curf == '+')
+        {   // skip until we meet the next separator, or end of string
+            char* nextpos = curn + 1;
+            while (nextpos < curn_end && *nextpos != '/')
+                nextpos = ++curn + 1;
+        }
+        else if (*curf == '#')
+            curn = curn_end - 1;    // skip until end of string
+        curf++;
+        curn++;
+    };
+
+    return (curn == curn_end) && (*curf == '\0');
+}
+
+
+
+template<class Network, class Timer, int a, int MAX_MESSAGE_HANDLERS>
+int MQTT::Client<Network, Timer, a, MAX_MESSAGE_HANDLERS>::deliverMessage(MQTTString& topicName, Message& message)
+{
+    int rc = FAILURE;
+
+    // we have to find the right message handler - indexed by topic
+    for (int i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
+    {
+        if (messageHandlers[i].topicFilter != 0 && (MQTTPacket_equals(&topicName, (char*)messageHandlers[i].topicFilter) ||
+                isTopicMatched((char*)messageHandlers[i].topicFilter, topicName)))
+        {
+            if (messageHandlers[i].fp.attached())
+            {
+                MessageData md(topicName, message);
+                messageHandlers[i].fp(md);
+                rc = SUCCESS;
+            }
+        }
+    }
+
+    if (rc == FAILURE && defaultMessageHandler.attached())
+    {
+        MessageData md(topicName, message);
+        defaultMessageHandler(md);
+        rc = SUCCESS;
+    }
+
+    return rc;
+}
+
+
+
+template<class Network, class Timer, int a, int b>
+int MQTT::Client<Network, Timer, a, b>::yield(unsigned long timeout_ms)
+{
+    int rc = SUCCESS;
+    Timer timer = Timer();
+
+    timer.countdown_ms(timeout_ms);
+    while (!timer.expired())
+    {
+        if (cycle(timer) < 0)
+        {
+            rc = FAILURE;
+            break;
+        }
+		Thread::wait(10);
+    }
+
+    return rc;
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::cycle(Timer& timer)
+{
+    /* get one piece of work off the wire and one pass through */
+
+    // read the socket, see what work is due
+    int packet_type = readPacket(timer);
+
+    int len = 0,
+        rc = SUCCESS;
+
+    switch (packet_type)
+    {
+        case FAILURE:
+        case BUFFER_OVERFLOW:
+            rc = packet_type;
+            break;
+        case CONNACK:
+        case PUBACK:
+        case SUBACK:
+            break;
+        case PUBLISH:
+        {
+            MQTTString topicName = MQTTString_initializer;
+            Message msg;
+            int intQoS;
+            if (MQTTDeserialize_publish((unsigned char*)&msg.dup, &intQoS, (unsigned char*)&msg.retained, (unsigned short*)&msg.id, &topicName,
+                                 (unsigned char**)&msg.payload, (int*)&msg.payloadlen, readbuf, MAX_MQTT_PACKET_SIZE) != 1)
+                goto exit;
+            msg.qos = (enum QoS)intQoS;
+#if MQTTCLIENT_QOS2
+            if (msg.qos != QOS2)
+#endif
+                deliverMessage(topicName, msg);
+#if MQTTCLIENT_QOS2
+            else if (isQoS2msgidFree(msg.id))
+            {
+                if (useQoS2msgid(msg.id))
+                    deliverMessage(topicName, msg);
+                else
+                    WARN("Maximum number of incoming QoS2 messages exceeded");
+            }
+#endif
+#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
+            if (msg.qos != QOS0)
+            {
+                if (msg.qos == QOS1)
+                    len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE, PUBACK, 0, msg.id);
+                else if (msg.qos == QOS2)
+                    len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE, PUBREC, 0, msg.id);
+                if (len <= 0)
+                    rc = FAILURE;
+                else
+                    rc = sendPacket(len, timer);
+                if (rc == FAILURE)
+                    goto exit; // there was a problem
+            }
+            break;
+#endif
+        }
+#if MQTTCLIENT_QOS2
+        case PUBREC:
+        case PUBREL:
+            unsigned short mypacketid;
+            unsigned char dup, type;
+            if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) != 1)
+                rc = FAILURE;
+            else if ((len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE, 
+                        (packet_type == PUBREC) ? PUBREL : PUBCOMP, 0, mypacketid)) <= 0)
+                rc = FAILURE;
+            else if ((rc = sendPacket(len, timer)) != SUCCESS) // send the PUBREL packet
+                rc = FAILURE; // there was a problem
+            if (rc == FAILURE)
+                goto exit; // there was a problem
+            if (packet_type == PUBREL)
+                freeQoS2msgid(mypacketid);
+            break;
+            
+        case PUBCOMP:
+            break;
+#endif
+        case PINGRESP:
+            ping_outstanding = false;
+            break;
+    }
+    keepalive();
+exit:
+    if (rc == SUCCESS)
+        rc = packet_type;
+    return rc;
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::keepalive()
+{
+    int rc = FAILURE;
+
+    if (keepAliveInterval == 0)
+    {
+        rc = SUCCESS;
+        goto exit;
+    }
+
+    if (last_sent.expired() || last_received.expired())
+    {
+        if (!ping_outstanding)
+        {
+            Timer timer(1000);
+            int len = MQTTSerialize_pingreq(sendbuf, MAX_MQTT_PACKET_SIZE);
+            if (len > 0 && (rc = sendPacket(len, timer)) == SUCCESS) // send the ping packet
+                ping_outstanding = true;
+        }
+    }
+
+exit:
+    return rc;
+}
+
+
+// only used in single-threaded mode where one command at a time is in process
+template<class Network, class Timer, int a, int b>
+int MQTT::Client<Network, Timer, a, b>::waitfor(int packet_type, Timer& timer)
+{
+    int rc = FAILURE;
+
+    do
+    {
+        if (timer.expired())
+            break; // we timed out
+    }
+    while ((rc = cycle(timer)) != packet_type);
+
+    return rc;
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::connect(MQTTPacket_connectData& options)
+{
+    Timer connect_timer(command_timeout_ms);
+    int rc = FAILURE;
+    int len = 0;
+
+    if (isconnected) // don't send connect packet again if we are already connected
+        goto exit;
+
+    this->keepAliveInterval = options.keepAliveInterval;
+    this->cleansession = options.cleansession;
+    if ((len = MQTTSerialize_connect(sendbuf, MAX_MQTT_PACKET_SIZE, &options)) <= 0)
+        goto exit;
+    if ((rc = sendPacket(len, connect_timer)) != SUCCESS)  // send the connect packet
+        goto exit; // there was a problem
+
+    if (this->keepAliveInterval > 0)
+        last_received.countdown(this->keepAliveInterval);
+    // this will be a blocking call, wait for the connack
+    if (waitfor(CONNACK, connect_timer) == CONNACK)
+    {
+        unsigned char connack_rc = 255;
+        bool sessionPresent = false;
+        if (MQTTDeserialize_connack((unsigned char*)&sessionPresent, &connack_rc, readbuf, MAX_MQTT_PACKET_SIZE) == 1)
+            rc = connack_rc;
+        else
+            rc = FAILURE;
+    }
+    else
+        rc = FAILURE;
+
+#if MQTTCLIENT_QOS2
+    // resend any inflight publish
+    if (inflightMsgid > 0 && inflightQoS == QOS2 && pubrel)
+    {
+        if ((len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE, PUBREL, 0, inflightMsgid)) <= 0)
+            rc = FAILURE;
+        else
+            rc = publish(len, connect_timer, inflightQoS);
+    }
+    else
+#endif
+#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
+    if (inflightMsgid > 0)
+    {
+        memcpy(sendbuf, pubbuf, MAX_MQTT_PACKET_SIZE);
+        rc = publish(inflightLen, connect_timer, inflightQoS);
+    }
+#endif
+
+exit:
+    if (rc == SUCCESS)
+        isconnected = true;
+    return rc;
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::connect()
+{
+    MQTTPacket_connectData default_options = MQTTPacket_connectData_initializer;
+    return connect(default_options);
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int MAX_MESSAGE_HANDLERS>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, MAX_MESSAGE_HANDLERS>::subscribe(const char* topicFilter, enum QoS qos, messageHandler messageHandler)
+{
+    int rc = FAILURE;
+    Timer timer(command_timeout_ms);
+    int len = 0;
+    MQTTString topic = {(char*)topicFilter, {0, 0}};
+
+    if (!isconnected)
+        goto exit;
+
+    len = MQTTSerialize_subscribe(sendbuf, MAX_MQTT_PACKET_SIZE, 0, packetid.getNext(), 1, &topic, (int*)&qos);
+    if (len <= 0)
+        goto exit;
+    if ((rc = sendPacket(len, timer)) != SUCCESS) // send the subscribe packet
+        goto exit;             // there was a problem
+
+    if (waitfor(SUBACK, timer) == SUBACK)      // wait for suback
+    {
+        int count = 0, grantedQoS = -1;
+        unsigned short mypacketid;
+        if (MQTTDeserialize_suback(&mypacketid, 1, &count, &grantedQoS, readbuf, MAX_MQTT_PACKET_SIZE) == 1)
+            rc = grantedQoS; // 0, 1, 2 or 0x80
+        if (rc != 0x80)
+        {
+            for (int i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
+            {
+                if (messageHandlers[i].topicFilter == 0)
+                {
+                    messageHandlers[i].topicFilter = topicFilter;
+                    messageHandlers[i].fp.attach(messageHandler);
+                    rc = 0;
+                    break;
+                }
+            }
+        }
+    }
+    else
+        rc = FAILURE;
+
+exit:
+    if (rc != SUCCESS)
+        cleanSession();
+    return rc;
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int MAX_MESSAGE_HANDLERS>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, MAX_MESSAGE_HANDLERS>::unsubscribe(const char* topicFilter)
+{
+    int rc = FAILURE;
+    Timer timer(command_timeout_ms);
+    MQTTString topic = {(char*)topicFilter, {0, 0}};
+    int len = 0;
+
+    if (!isconnected)
+        goto exit;
+
+    if ((len = MQTTSerialize_unsubscribe(sendbuf, MAX_MQTT_PACKET_SIZE, 0, packetid.getNext(), 1, &topic)) <= 0)
+        goto exit;
+    if ((rc = sendPacket(len, timer)) != SUCCESS) // send the unsubscribe packet
+        goto exit; // there was a problem
+
+    if (waitfor(UNSUBACK, timer) == UNSUBACK)
+    {
+        unsigned short mypacketid;  // should be the same as the packetid above
+        if (MQTTDeserialize_unsuback(&mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) == 1)
+        {
+            rc = 0;
+
+            // remove the subscription message handler associated with this topic, if there is one
+            for (int i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
+            {
+                if (messageHandlers[i].topicFilter && strcmp(messageHandlers[i].topicFilter, topicFilter) == 0)
+                {
+                    messageHandlers[i].topicFilter = 0;
+                    break;
+                }
+            }
+        }
+    }
+    else
+        rc = FAILURE;
+
+exit:
+    if (rc != SUCCESS)
+        cleanSession();
+    return rc;
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::publish(int len, Timer& timer, enum QoS qos)
+{
+    int rc;
+
+    if ((rc = sendPacket(len, timer)) != SUCCESS) // send the publish packet
+        goto exit; // there was a problem
+
+#if MQTTCLIENT_QOS1
+    if (qos == QOS1)
+    {
+        if (waitfor(PUBACK, timer) == PUBACK)
+        {
+            unsigned short mypacketid;
+            unsigned char dup, type;
+            if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) != 1)
+                rc = FAILURE;
+            else if (inflightMsgid == mypacketid)
+                inflightMsgid = 0;
+        }
+        else
+            rc = FAILURE;
+    }
+#elif MQTTCLIENT_QOS2
+    else if (qos == QOS2)
+    {
+        if (waitfor(PUBCOMP, timer) == PUBCOMP)
+        {
+            unsigned short mypacketid;
+            unsigned char dup, type;
+            if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) != 1)
+                rc = FAILURE;
+            else if (inflightMsgid == mypacketid)
+                inflightMsgid = 0;
+        }
+        else
+            rc = FAILURE;
+    }
+#endif
+
+exit:
+    if (rc != SUCCESS)
+        cleanSession();
+    return rc;
+}
+
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::publish(const char* topicName, void* payload, size_t payloadlen, unsigned short& id, enum QoS qos, bool retained)
+{
+    int rc = FAILURE;
+    Timer timer(command_timeout_ms);
+    MQTTString topicString = MQTTString_initializer;
+    int len = 0;
+
+    if (!isconnected)
+        goto exit;
+
+    topicString.cstring = (char*)topicName;
+
+#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
+    if (qos == QOS1 || qos == QOS2)
+        id = packetid.getNext();
+#endif
+
+    len = MQTTSerialize_publish(sendbuf, MAX_MQTT_PACKET_SIZE, 0, qos, retained, id,
+              topicString, (unsigned char*)payload, payloadlen);
+    if (len <= 0)
+        goto exit;
+
+#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
+    if (!cleansession)
+    {
+        memcpy(pubbuf, sendbuf, len);
+        inflightMsgid = id;
+        inflightLen = len;
+        inflightQoS = qos;
+#if MQTTCLIENT_QOS2
+        pubrel = false;
+#endif
+    }
+#endif
+
+    rc = publish(len, timer, qos);
+exit:
+    return rc;
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::publish(const char* topicName, void* payload, size_t payloadlen, enum QoS qos, bool retained)
+{
+    unsigned short id = 0;  // dummy - not used for anything
+    return publish(topicName, payload, payloadlen, id, qos, retained);
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::publish(const char* topicName, Message& message)
+{
+    return publish(topicName, message.payload, message.payloadlen, message.qos, message.retained);
+}
+
+
+template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
+int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::disconnect()
+{
+    int rc = FAILURE;
+    Timer timer(command_timeout_ms);            // we might wait for incomplete incoming publishes to complete
+    int len = MQTTSerialize_disconnect(sendbuf, MAX_MQTT_PACKET_SIZE);
+    if (len > 0)
+        rc = sendPacket(len, timer);            // send the disconnect packet
+
+    if (cleansession)
+        cleanSession();
+    else
+        isconnected = false;
+    return rc;
+}
+
+
+#endif
\ No newline at end of file