rp2da2.mqtt.mqtt_client.MQTTPacketOut

class documentation

class MQTTPacketOut:

Constructor: MQTTPacketOut(pkt_type, flags)

MQTT Control Packet Out

This class is used to construct MQTT control packets to be sent to the broker. It provides methods to add bytes, strings and payloads to the packet. The packet is constructed as a bytearray and the write method sends the complete packet. The first byte is the control packet type and flags, the following bytes hold the remaining packet length. The remaining length is calculated as the number of bytes in the packet excluding the control byte and length bytes. The packet is constructed in the order of the MQTT protocol specification.

Method	`__init__`	Construct MQTT Control Packet out
Method	`add_byte`	Add a byte to the packet
Method	`add_payload`	Add a payload to the packet
Method	`add_str`	Add a string to the packet
Method	`add_uint16`	Add a 16 bit unsigned integer to the packet
Async Method	`write_buff`	Write the complete packet
Instance Variable	`_buffer`	Undocumented
Instance Variable	`_header`	Undocumented

def __init__(self, pkt_type, flags=0): ¶

Construct MQTT Control Packet out

Set up first byte as control packet type and flags. Initialise second byte (length) to 0

Parameters
pkt_type	MQTT Control Packet type
flags	Packet control flags

def add_byte(self, b): ¶

Add a byte to the packet

Parameters
b	the byte to add to the packet

def add_payload(self, s): ¶

Add a payload to the packet

The payload is added as a UTF-8 encoded byte string.

Parameters
s	the payload to add to the packet

def add_str(self, s): ¶

Add a string to the packet

The string is added as a UTF-8 encoded byte string. The length of the string is added as a 16 bit unsigned integer.

Parameters
s	the string to add to the packet

def add_uint16(self, i): ¶

Add a 16 bit unsigned integer to the packet

Parameters
i	the integer to add to the packet

async def write_buff(self, writer): ¶

Write the complete packet

The first byte is the control packet type and flags, the following bytes are the remaining length of the packet.

See MQTT spec 2.2.3 for remaining length bytes generation psuedo code.

Parameters
writer	the write stream

Returns
True if write successful else False

_buffer = ¶

Undocumented

_header = ¶

Undocumented