dataPublisher class

The dataPublisher class is a virtual class used by other publishers to distribute data online.

A dataPublisher is a abstract concept. It is something that "watches" the logger for new data and correctly formats and sends that data to some online web service.

Derived classes

class AWS_IoT_Publisher: The AWS_IoT_Publisher subclass of dataPublisher for publishing data to AWS IoT Core using the MQTT protocol.
class DreamHostPublisher: The DreamHostPublisher subclass of dataPublisher is for publishing data to the Stroud Center's now-deprecated DreamHost based live sensor data system.
class EnviroDIYPublisher: The EnviroDIYPublisher subclass of dataPublisher for publishing data to the Monitor My Watershed/EnviroDIY data portal at https://monitormywatershed.org/ (formerly at http://data.enviroDIY.org).
class S3PresignedPublisher: The S3PresignedPublisher subclass of dataPublisher is for publishing data to S3 over a pre-signed URL.
class ThingSpeakPublisher: The ThingSpeakPublisher subclass of dataPublisher for publishing data to ThingSpeak using the MQTT protocol.
class UbidotsPublisher: The UbidotsPublisher subclass of dataPublisher for publishing data to the Ubidots data portal at https://ubidots.com.

Constructors, destructors, conversion operators

dataPublisher(): Construct a new data publisher object untied to any logger or client.
dataPublisher(Logger& baseLogger, int sendEveryX = 1) explicit: Construct a new data publisher object using a single client created on the TinyGSM based logger modem.
dataPublisher(Logger& baseLogger, Client* inClient, int sendEveryX = 1): Construct a new data publisher object.
~dataPublisher() virtual: Destroy the data publisher object - no action is taken.

Public functions

void setClient(Client* inClient): Set the Client object.
void setSendInterval(int sendEveryX): Sets the interval (in units of the logging interval) between attempted data transmissions.
void attachToLogger(Logger& baseLogger): Attach the publisher to a logger.
void setModemPointer(loggerModem& modemPointer): Set the pointer to a loggerModem instance.
void begin(Logger& baseLogger, Client* inClient): Begin the publisher - linking it to the client and logger.
void begin(Logger& baseLogger): Begin the publisher - linking it to the logger but not attaching a client.
String getEndpoint(void) -> String pure virtual: Get the destination for published data - generally the host name of the data receiver.
bool connectionNeeded(void) -> bool virtual: Checks if the publisher needs an internet connection for the next publishData call (as opposed to just buffering data internally).
int16_t publishData(Client* outClient, bool forceFlush = false) -> int16_t pure virtual: Opens a socket to the correct receiver and sends out the formatted data.
int16_t publishData(bool forceFlush = false) -> int16_t virtual: Open a socket to the correct receiver and send out the formatted data.
int16_t publishMetadata(Client* outClient) -> int16_t virtual: Open a socket to the correct receiver and send out metadata about the current logger setup.
int16_t publishMetadata() -> int16_t virtual: Open a socket to the correct receiver and send out metadata about the current logger setup.
int16_t sendData(Client* outClient) -> int16_t deprecated in v0.22.5 virtual: Retained for backwards compatibility; use publishData(Client* outClient) in new code.
int16_t sendData() -> int16_t deprecated in v0.22.5 virtual: Retained for backwards compatibility; use publishData() in new code.
String parseMQTTState(int state) -> String: Translate a PubSubClient code into a String with the code explanation.

Protected static functions

static void txBufferInit(Client* outClient): Initialize the TX buffer to be empty and start writing to the given client.
static void txBufferAppend(const char* data, size_t length, bool debug_flush = true): Append the given data to the TX buffer, flushing if necessary.
static void txBufferAppend(const char* s, bool debug_flush = true): Append the given string to the TX buffer, flushing if necessary.
static void txBufferAppend(char c, bool debug_flush = true): Append the given char to the TX buffer, flushing if necessary.
static void txBufferFlush(bool debug_flush = true): Write the TX buffer contents to the initialized stream and also to the debugging port.

Protected functions

Client* createClient() -> Client* virtual: Use the connected base logger's logger modem and underlying TinyGSM instance to create a new client for the publisher.
void deleteClient(Client* client) virtual: Delete a created client. We need to pass this through to avoid a memory leak because we cannot delete from the pointer because the destructor for a client in the Arduino core isn't virtual.

Protected static variables

static char txBuffer: The buffer for outgoing data.
static Client* txBufferOutClient: The pointer to the client instance the TX buffer is writing to.
static size_t txBufferLen: The number of used characters in the TX buffer.
static const char* getHeader: the text "GET "
static const char* postHeader: the text "POST "
static const char* putHeader: the text "PUT "
static const char* HTTPtag: the text " HTTP/1.1"
static const char* hostHeader: the text "\r\nHost: "

Protected variables

Logger* _baseLogger: The internal pointer to the logger instance to be used.
loggerModem* _baseModem: The internal pointer to the base logger's modem instance to be used.
Client* _inClient: The internal pointer to the client instance to be used.
int _sendEveryX: Interval (in units of the logging interval) between attempted data transmissions. Not respected by all publishers.

Function documentation

dataPublisher::dataPublisher()

Construct a new data publisher object untied to any logger or client.

dataPublisher::dataPublisher(Logger& baseLogger, int sendEveryX = 1) explicit

Construct a new data publisher object using a single client created on the TinyGSM based logger modem.

Parameters
baseLogger	The logger supplying the data to be published
sendEveryX	Interval (in units of the logging interval) between attempted data transmissions. Not respected by all publishers.

dataPublisher::dataPublisher(Logger& baseLogger, Client* inClient, int sendEveryX = 1)

Construct a new data publisher object.

Parameters
baseLogger	The logger supplying the data to be published
inClient	An Arduino client instance to use to print data to. Allows the use of any type of client and multiple clients tied to a single TinyGSM modem instance
sendEveryX	Interval (in units of the logging interval) between attempted data transmissions. Not respected by all publishers.

void dataPublisher::setClient(Client* inClient)

Set the Client object.

Parameters
inClient	A pointer to an Arduino client instance

Gives the publisher a client instance to use to "print" data.

void dataPublisher::setSendInterval(int sendEveryX)

Sets the interval (in units of the logging interval) between attempted data transmissions.

Parameters
sendEveryX	Interval (in units of the logging interval) between attempted data transmissions. Not respected by all publishers.

void dataPublisher::attachToLogger(Logger& baseLogger)

Attach the publisher to a logger.

Parameters
baseLogger	A reference to the ModularSensors logger instance

The publisher must be tied to a data logger to provide it with the data to be published.

void dataPublisher::setModemPointer(loggerModem& modemPointer)

Set the pointer to a loggerModem instance.

Parameters
modemPointer	A reference to the ModularSensors loggerModem instance

void dataPublisher::begin(Logger& baseLogger, Client* inClient)

Begin the publisher - linking it to the client and logger.

Parameters
baseLogger	The logger supplying the data to be published
inClient	An Arduino client instance to use to print data to. Allows the use of any type of client and multiple clients tied to a single TinyGSM modem instance

This can be used as an alternative to adding the logger and client in the constructor.

void dataPublisher::begin(Logger& baseLogger)

Begin the publisher - linking it to the logger but not attaching a client.

Parameters
baseLogger	The logger supplying the data to be published

This can be used as an alternative to adding the logger and client in the constructor.

String dataPublisher::getEndpoint(void) pure virtual

Get the destination for published data - generally the host name of the data receiver.

Returns	String The URL or HOST to receive published data

bool dataPublisher::connectionNeeded(void) virtual

Checks if the publisher needs an internet connection for the next publishData call (as opposed to just buffering data internally).

Returns	bool True if an internet connection is needed for the next publish.

int16_t dataPublisher::publishData(Client* outClient, bool forceFlush = false) pure virtual

Opens a socket to the correct receiver and sends out the formatted data.

Parameters
outClient	An Arduino client instance to use to print data to. Allows the use of any type of client and multiple clients tied to a single TinyGSM modem instance
forceFlush	Ask the publisher to flush buffered data immediately.
Returns	int16_t The result of publishing data. May be an http response code or a result code from PubSubClient.

This depends on an internet connection already having been made and a client being available.

int16_t dataPublisher::publishData(bool forceFlush = false) virtual

Open a socket to the correct receiver and send out the formatted data.

Parameters
forceFlush	Ask the publisher to flush buffered data immediately.
Returns	int16_t The result of publishing data. May be an http response code or a result code from PubSubClient. Defaults to -2 if the publisher fails to create a client.

This depends on an internet connection already having been made and either a client having been linked to the publisher or a logger modem having been linked to the logger linked to the publisher.

int16_t dataPublisher::publishMetadata(Client* outClient) virtual

Open a socket to the correct receiver and send out metadata about the current logger setup.

Parameters
outClient	An Arduino client instance to use to print data to. Allows the use of any type of client and multiple clients tied to a single TinyGSM modem instance
Returns	int16_t The result of publishing data. May be an http response code or a result code from PubSubClient.

This is to be used only when the logger is starting up! As the metadata doesn't generally change after start up, there's no reason to call this function any other time. There is no sensor data included in this metadata! If there is metadata that has to be included with each data post, that should be included in the publishData function. Because there is no sensor data included in this metadata and it's only to be called at boot, there's no forceFlush option for this function.

This depends on an internet connection already having been made and a client being available.

int16_t dataPublisher::publishMetadata() virtual

Open a socket to the correct receiver and send out metadata about the current logger setup.

Returns	int16_t The result of publishing data. May be an http response code or a result code from PubSubClient.

This depends on an internet connection already having been made and a client being available.

int16_t dataPublisher::sendData(Client* outClient) virtual deprecated in v0.22.5

Retained for backwards compatibility; use publishData(Client* outClient) in new code.

Parameters
outClient	An Arduino client instance to use to print data to. Allows the use of any type of client and multiple clients tied to a single TinyGSM modem instance
Returns	int16_t The result of publishing data. May be an http response code or a result code from PubSubClient.

int16_t dataPublisher::sendData() virtual deprecated in v0.22.5

Retained for backwards compatibility; use publishData() in new code.

Returns	int16_t The result of publishing data. May be an http response code or a result code from PubSubClient.

String dataPublisher::parseMQTTState(int state)

Translate a PubSubClient code into a String with the code explanation.

Parameters
state	A result code returned by a PubSubClient action
Returns	String The meaning of the code

static void dataPublisher::txBufferInit(Client* outClient) protected

Initialize the TX buffer to be empty and start writing to the given client.

Parameters
outClient	The client to transmit to.

static void dataPublisher::txBufferAppend(const char* data, size_t length, bool debug_flush = true) protected

Append the given data to the TX buffer, flushing if necessary.

Parameters
data	The data start pointer.
length	The number of bytes to add.
debug_flush	If true, flush the TX buffer to the debugging port.

static void dataPublisher::txBufferAppend(const char* s, bool debug_flush = true) protected

Append the given string to the TX buffer, flushing if necessary.

Parameters
s	The null-terminated string to append.
debug_flush	If true, flush the TX buffer to the debugging port.

static void dataPublisher::txBufferAppend(char c, bool debug_flush = true) protected

Append the given char to the TX buffer, flushing if necessary.

Parameters
c	The char to append.
debug_flush	If true, flush the TX buffer to the debugging port.

static void dataPublisher::txBufferFlush(bool debug_flush = true) protected

Write the TX buffer contents to the initialized stream and also to the debugging port.

Parameters
debug_flush	If true, flush the TX buffer to the debugging port.

Client* dataPublisher::createClient() virtual protected

Use the connected base logger's logger modem and underlying TinyGSM instance to create a new client for the publisher.

Returns	Client* A pointer to an Arduino client instance

void dataPublisher::deleteClient(Client* client) virtual protected

Delete a created client. We need to pass this through to avoid a memory leak because we cannot delete from the pointer because the destructor for a client in the Arduino core isn't virtual.

Parameters
client	The client to delete