Connects to DLink DSP-215 to print out realtime wattage used

wattMeter.py

#!/usr/bin/python
# Modified from https://github.com/fake-name/DSP-W215-Poller

import time
import urllib.parse
import urllib.request
import random

DSP_OUTLET_IP = '192.168.1.2'
UPDATE_INTERVAL = 2

class DSPInterface(object):
	def __init__(self, plugIp):
		self.ip = plugIp

	def getReading(self):
		pass

		postData = {'request': 'create_chklst'}
		postData = urllib.parse.urlencode(postData).encode("ascii")

		req = urllib.request.Request("http://{ip}/my_cgi.cgi?{rand}".format(ip=self.ip, rand=str(random.random())), data=postData)
		response = urllib.request.urlopen(req)
		ret = response.read().decode("utf-8")
		ret = ret.strip()
		lines = ret.split("\n")

		retVal = None

		for line in lines:
			if line.startswith("Meter Watt:"):
				power = line.split()[-1]
				if retVal:
					raise ValueError("Two power readings in one response?")
				try:
					retVal = float(power)
				except ValueError:
					print("Error on string '%s'" % line)
					return None

		return retVal

if __name__ == "__main__":
	outlet = DSPInterface(DSP_OUTLET_IP)
	print("Plug opened. Handle = %s" % outlet)

	nextRun = time.time() + UPDATE_INTERVAL
	while 1:
		powerReading = outlet.getReading()
		print(powerReading)

		while time.time() < nextRun:
			time.sleep(1)
		nextRun += UPDATE_INTERVAL