# mqtt/client.py

from __future__ import absolute_import

import os

from POULibrary import POULibrary

import util.paths as paths

mqtt_python_lib_code = """

def MQTT_publish(clientname, topic, payload, QoS = 1, Retained = False):

c_function_name = "__mqtt_python_publish_" + clientname

c_function = getattr(PLCBinary, c_function_name)

c_function.restype = ctypes.c_int # error or 0

c_function.argtypes = [

ctypes.c_char_p, # topic

ctypes.c_char_p, # data

ctypes.c_uint32, # datalen

ctypes.c_uint8, # QoS

ctypes.c_uint8, # Retained

]

res = c_function(topic, payload, len(payload), QoS, Retained)

return res

# C per client CallBack type for __mqtt_python_onmsg_{name}

mqtt_c_cb_onmsg_type = ctypes.CFUNCTYPE(ctypes.c_int, # return

ctypes.c_char_p, # topic

ctypes.POINTER(ctypes.c_char), # data

ctypes.c_uint32) # data length

# C per client CallBack type for __mqtt_python_resub_{name}

mqtt_c_cb_resub_type = ctypes.CFUNCTYPE(ctypes.c_int) # return

# CallBacks management

# - each call to MQTT_subscribe registers a callback

MQTT_subscribers_cbs = {}

# - one callback registered to C side per client

MQTT_client_cbs = {}

def mqtt_per_client_cb_factory(clientname):

def per_client_onmsg_cb(topic, dataptr, datalen):

payload = ctypes.string_at(dataptr, datalen)

subscriber,_Qos = MQTT_subscribers_cbs[clientname].get(topic, None)

if subscriber:

subscriber(topic, payload)

return 0

return 1

def per_client_resub_cb():

for topic,(_cb,QoS) in MQTT_subscribers_cbs[clientname].items():

_MQTT_subscribe(clientname, topic, QoS)

return 1

return per_client_onmsg_cb,per_client_resub_cb

def _MQTT_subscribe(clientname, topic, QoS):

c_function_name = "__mqtt_python_subscribe_" + clientname

c_function = getattr(PLCBinary, c_function_name)

c_function.restype = ctypes.c_int # error or 0

c_function.argtypes = [

ctypes.c_char_p, # topic

ctypes.c_uint8] # QoS

return c_function(topic, QoS)

def MQTT_subscribe(clientname, topic, cb, QoS = 1):

global MQTT_client_cbs, MQTT_subscribers_cbs

c_cbs = MQTT_client_cbs.get(clientname, None)

if c_cbs is None:

cb_onmsg, cb_resub = mqtt_per_client_cb_factory(clientname)

c_cbs = (mqtt_c_cb_onmsg_type(cb_onmsg),

mqtt_c_cb_resub_type(cb_resub))

MQTT_client_cbs[clientname] = c_cbs

register_c_function = getattr(PLCBinary, "__mqtt_python_callback_setter_"+clientname )

register_c_function.argtypes = [mqtt_c_cb_onmsg_type, mqtt_c_cb_resub_type]

register_c_function(*c_cbs)

MQTT_subscribers_cbs.setdefault(clientname, {})[topic] = (cb, QoS)

res = _MQTT_subscribe(clientname, topic, QoS)

return res

"""

class MQTTLibrary(POULibrary):

def GetLibraryPath(self):

return paths.AbsNeighbourFile(__file__, "pous.xml")

def Generate_C(self, buildpath, varlist, IECCFLAGS):

runtimefile_path = os.path.join(buildpath, "runtime_00_mqtt.py")

runtimefile = open(runtimefile_path, 'w')

runtimefile.write(mqtt_python_lib_code)

runtimefile.close()

return ((["mqtt"], [], False), "",

("runtime_00_mqtt.py", open(runtimefile_path, "rb")))