Access method variable from other method python

Question

I have a problem accessing client.close() in readholdingregisters() from closeconnection() in the code below:

class EnergyMeter:
    def __init__(self, model, gatewayipaddress, port ,deviceid):
        self.model = model
        self.gatewayipaddress = gatewayipaddress
        self.port = port
        self.deviceid = deviceid

    def readholdingregisters(self, startingregister, numberofregisters):
        from pymodbus3.client.sync import ModbusTcpClient as ModbusClient
        client = ModbusClient(self.gatewayipaddress, port=self.port)
        client.connect()
        if #some code here:
            #some other code here
            return concatResult
        else:
            return otherResult

Here I want to close the connection client.connect() from readholdingregisters():

    def closeconnection(self):
        EnergyMeter.readholdingregisters().client.close()??????????????????

Can you plase give me a good solution how to do it?

Store the connection on the instance just like you do with your other data... — kindall, Feb 07 '17 at 21:13
I am not sure I understand what you mean. Can you write a small example? — KaloyanGeorgiev, Feb 07 '17 at 21:25

score 0 · Answer 1 · answered Feb 07 '17 at 21:24

from pymodbus3.client.sync import ModbusTcpClient as ModbusClient

class EnergyMeter:
    def __init__(self, model, gatewayipaddress, port ,deviceid):
        self.model = model
        self.gatewayipaddress = gatewayipaddress
        self.port = port
        self.deviceid = deviceid
        self.client = ModbusClient(self.gatewayipaddress, port=self.port)
        self.client.connect()

    def readholdingregisters(self, startingregister, numberofregisters):
        if #some code here:
            #some other code here
            return concatResult
        else:
            return otherResult

Then, to close, you call energy_meter.client.close() for whatever energy_meter you want to close.

@KaloyanGeorgiev If it solved your issue, don't forget to check the "Accept Answer" check mark. Also, up-vote answers which you found helpful (including your accepted answer) — TemporalWolf, Feb 07 '17 at 21:45

score 0 · Accepted Answer · edited May 23 '17 at 12:01

Usual approach is , make client as datamember of class.

        self.client = ModbusClient(self.gatewayipaddress, port=self.port)
        self.client.connect()
        #some code here


    def closeconnection(self):
        self.readholdingregisters()
        self.client.close()

However if you want to access method through class EnergyMeter.readholdingregisters()

Then it should be declared as staticmethod or classmethod and this method should return client instance. Link

Access method variable from other method python

Here I want to close the connection client.connect() from readholdingregisters():

2 Answers2