uint8_t Adafruit_MQTT::pingPacket(uint8_t *packet) {
packet[0] = MQTT_CTRL_PINGREQ << 4;
packet[1] = 0;
DEBUG_PRINTLN(F("MQTT ping packet:"));
DEBUG_PRINTBUFFER(buffer, 2);
return 2;
}
uint8_t Adafruit_MQTT::subscribePacket(uint8_t *packet, const char *topic,
uint8_t qos) {
uint8_t *p = packet;
uint16_t len;
p[0] = MQTT_CTRL_SUBSCRIBE << 4 | MQTT_QOS_1 << 1;
// fill in packet[1] last
p+=2;
// put in a message id,
p[0] = 0xAD;
p[1] = 0xAF;
p+=2;
p = stringprint_P(p, topic);
p[0] = qos;
p++;
len = p - packet;
packet[1] = len-2; // don't include the 2 bytes of fixed header data
DEBUG_PRINTLN(F("MQTT subscription packet:"));
DEBUG_PRINTBUFFER(buffer, len);
return len;
}
bool Adafruit_MQTT::publish(const char *topic, const char *data, uint8_t qos) {
// Construct and send publish packet.
uint8_t len = publishPacket(buffer, topic, data, qos);
if (!sendPacket(buffer, len))
return false;
// If QOS level is high enough verify the response packet.
if (qos > 0) {
len = readPacket(buffer, 4, PUBLISH_TIMEOUT_MS);
DEBUG_PRINT(F("Publish QOS1+ reply:\t"));
DEBUG_PRINTBUFFER(buffer, len);
//TODO: Verify response packet?
}
return true;
}
Adafruit_MQTT_Subscribe *Adafruit_MQTT::readSubscription(int16_t timeout) {
uint8_t i, topiclen, datalen;
// Check if data is available to read.
uint16_t len = readPacket(buffer, MAXBUFFERSIZE, timeout, true); // return one full packet
if (!len)
return NULL; // No data available, just quit.
DEBUG_PRINTBUFFER(buffer, len);
// Parse out length of packet.
topiclen = buffer[3];
DEBUG_PRINT(F("Looking for subscription len ")); DEBUG_PRINTLN(topiclen);
// Find subscription associated with this packet.
for (i=0; i<MAXSUBSCRIPTIONS; i++) {
if (subscriptions[i]) {
// Skip this subscription if its name length isn't the same as the
// received topic name.
if (strlen_P(subscriptions[i]->topic) != topiclen)
continue;
// Stop if the subscription topic matches the received topic. Be careful
// to make comparison case insensitive.
if (strncasecmp_P((char*)buffer+4, subscriptions[i]->topic, topiclen) == 0) {
DEBUG_PRINT(F("Found sub #")); DEBUG_PRINTLN(i);
break;
}
}
}
if (i==MAXSUBSCRIPTIONS) return NULL; // matching sub not found ???
// zero out the old data
memset(subscriptions[i]->lastread, 0, SUBSCRIPTIONDATALEN);
datalen = len - topiclen - 4;
if (datalen > SUBSCRIPTIONDATALEN) {
datalen = SUBSCRIPTIONDATALEN-1; // cut it off
}
// extract out just the data, into the subscription object itself
memcpy(subscriptions[i]->lastread, buffer+4+topiclen, datalen);
subscriptions[i]->datalen = datalen;
DEBUG_PRINT(F("Data len: ")); DEBUG_PRINTLN(datalen);
DEBUG_PRINT(F("Data: ")); DEBUG_PRINTLN((char *)subscriptions[i]->lastread);
// return the valid matching subscription
return subscriptions[i];
}
bool Adafruit_MQTT::unsubscribe(Adafruit_MQTT_Subscribe *sub) {
uint8_t i;
// see if we are already subscribed
for (i=0; i<MAXSUBSCRIPTIONS; i++) {
if (subscriptions[i] == sub) {
DEBUG_PRINTLN(F("Found matching subscription and attempting to unsubscribe."));
// Construct and send unsubscribe packet.
uint8_t len = unsubscribePacket(buffer, subscriptions[i]->topic);
// sending unsubscribe failed
if (! sendPacket(buffer, len))
return false;
// if QoS for this subscription is 1 or 2, we need
// to wait for the unsuback to confirm unsubscription
if(subscriptions[i]->qos > 0 && MQTT_PROTOCOL_LEVEL > 3) {
// wait for UNSUBACK
len = readPacket(buffer, 5, CONNECT_TIMEOUT_MS);
DEBUG_PRINT(F("UNSUBACK:\t"));
DEBUG_PRINTBUFFER(buffer, len);
if ((len != 5) || (buffer[0] != (MQTT_CTRL_UNSUBACK << 4))) {
return false; // failure to unsubscribe
}
}
subscriptions[i] = 0;
return true;
}
}
// subscription not found, so we are unsubscribed
return true;
}
uint8_t Adafruit_MQTT::publishPacket(uint8_t *packet, const char *topic,
const char *data, uint8_t qos) {
uint8_t *p = packet;
uint16_t len;
p[0] = MQTT_CTRL_PUBLISH << 4 | qos << 1;
// fill in packet[1] last
p+=2;
p = stringprint_P(p, topic);
memcpy(p, data, strlen(data));
p+=strlen(data);
len = p - packet;
packet[1] = len-2; // don't include the 2 bytes of fixed header data
DEBUG_PRINTLN(F("MQTT publish packet:"));
DEBUG_PRINTBUFFER(buffer, len);
return len;
}
// The current MQTT spec is 3.1.1 and available here:
// http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718028
// However this connect packet and code follows the MQTT 3.1 spec here (some
// small differences in the protocol):
// http://public.dhe.ibm.com/software/dw/webservices/ws-mqtt/mqtt-v3r1.html#connect
uint8_t Adafruit_MQTT::connectPacket(uint8_t *packet) {
uint8_t *p = packet;
uint16_t len;
// fixed header, connection messsage no flags
p[0] = (MQTT_CTRL_CONNECT << 4) | 0x0;
p+=2;
// fill in packet[1] last
p = stringprint_P(p, PSTR("MQTT"));
p[0] = MQTT_PROTOCOL_LEVEL;
p++;
p[0] = MQTT_CONN_CLEANSESSION;
if (pgm_read_byte(username) != 0)
p[0] |= MQTT_CONN_USERNAMEFLAG;
if (pgm_read_byte(password) != 0)
p[0] |= MQTT_CONN_PASSWORDFLAG;
p++;
// TODO: add WILL support?
p[0] = MQTT_CONN_KEEPALIVE >> 8;
p++;
p[0] = MQTT_CONN_KEEPALIVE & 0xFF;
p++;
p = stringprint_P(p, clientid, 23); // Limit client ID to first 23 characters.
if (pgm_read_byte(username) != 0) {
p = stringprint_P(p, username);
}
if (pgm_read_byte(password) != 0) {
p = stringprint_P(p, password);
}
len = p - packet;
packet[1] = len-2; // don't include the 2 bytes of fixed header data
DEBUG_PRINTLN(F("MQTT connect packet:"));
DEBUG_PRINTBUFFER(buffer, len);
return len;
}
// The current MQTT spec is 3.1.1 and available here:
// http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html#_Toc398718028
// However this connect packet and code follows the MQTT 3.1 spec here (some
// small differences in the protocol):
// http://public.dhe.ibm.com/software/dw/webservices/ws-mqtt/mqtt-v3r1.html#connect
uint8_t Adafruit_MQTT::connectPacket(uint8_t *packet) {
uint8_t *p = packet;
uint16_t len;
// fixed header, connection messsage no flags
p[0] = (MQTT_CTRL_CONNECT << 4) | 0x0;
p+=2;
// fill in packet[1] last
#if MQTT_PROTOCOL_LEVEL == 3
p = stringprint_P(p, PSTR("MQIsdp"));
#elif MQTT_PROTOCOL_LEVEL == 4
p = stringprint_P(p, PSTR("MQTT"));
#else
#error "MQTT level not supported"
#endif
p[0] = MQTT_PROTOCOL_LEVEL;
p++;
// always clean the session
p[0] = MQTT_CONN_CLEANSESSION;
// set the will flags if needed
if (will_topic && pgm_read_byte(will_topic) != 0) {
p[0] |= MQTT_CONN_WILLFLAG;
if(will_qos == 1)
p[0] |= MQTT_CONN_WILLQOS_1;
else if(will_qos == 2)
p[0] |= MQTT_CONN_WILLQOS_2;
if(will_retain == 1)
p[0] |= MQTT_CONN_WILLRETAIN;
}
if (pgm_read_byte(username) != 0)
p[0] |= MQTT_CONN_USERNAMEFLAG;
if (pgm_read_byte(password) != 0)
p[0] |= MQTT_CONN_PASSWORDFLAG;
p++;
p[0] = MQTT_CONN_KEEPALIVE >> 8;
p++;
p[0] = MQTT_CONN_KEEPALIVE & 0xFF;
p++;
if(MQTT_PROTOCOL_LEVEL == 3) {
p = stringprint_P(p, clientid, 23); // Limit client ID to first 23 characters.
} else {
if (pgm_read_byte(clientid) != 0) {
p = stringprint_P(p, clientid);
} else {
p[0] = 0x0;
p++;
p[0] = 0x0;
p++;
DEBUG_PRINTLN(F("SERVER GENERATING CLIENT ID"));
}
}
if (will_topic && pgm_read_byte(will_topic) != 0) {
p = stringprint_P(p, will_topic);
p = stringprint_P(p, will_payload);
}
if (pgm_read_byte(username) != 0) {
p = stringprint_P(p, username);
}
if (pgm_read_byte(password) != 0) {
p = stringprint_P(p, password);
}
len = p - packet;
packet[1] = len-2; // don't include the 2 bytes of fixed header data
DEBUG_PRINTLN(F("MQTT connect packet:"));
DEBUG_PRINTBUFFER(buffer, len);
return len;
}