python/currcost.py

@@ -0,0 +1,91 @@
+import xml.parsers.expat
+import serial
+
+# Parses data from a CurrentCost meter
+# 
+# Note that this is provided to help get you started, but it lacks careful 
+#  error-handling or proper documentation.
+# 
+# If you have any questions about it, or even just find it useful, please do 
+#  let me know - dale.lane@gmail.com
+# 
+# 
+#  Dale Lane (http://dalelane.co.uk/blog)
+# 
+
+YOURCOMPORT = "COM21"
+
+
+# this class lets you store the CurrentCost XML data as a Python object
+from currentcostdata           import CurrentCostUpdate
+
+# this class lets you translate the CurrentCost data into values and their timestamps
+from currentcostdatafunctions  import CurrentCostDataFunctions
+
+# this class lets you store your CurrentCost data
+from currentcostdatastore      import CurrentCostDataStore
+
+
+# XML parsing functions 
+def start_element(name, attrs):
+    global currentelement
+    currentelement = name
+def end_element(name):
+    global currentelement
+    currentelement = "none"
+def char_data(data):
+    global currentelement, newupd
+    newupd.UpdateProperty(currentelement, data)
+
+currentelement = "none"
+
+# object to represent the CurrentCost data received
+newupd = CurrentCostUpdate ()
+
+# objects to parse and store the data
+ccfuncs = CurrentCostDataFunctions()
+ccdb = CurrentCostDataStore()
+
+ser = None
+
+try:
+    # connect to the CurrentCost meter
+    ser = serial.Serial(port=YOURCOMPORT, timeout=3)
+except serial.SerialException, msg:
+    print("Failed to connect to CurrentCost meter :: " + str(msg))
+    exit(1)
+
+# we keep trying to get an update from the CurrentCost meter 
+#  until we successfully populate the CurrentCost data object
+
+while newupd.WattsDay01 == -1:
+
+    # read a line of XML from the CurrentCost meter
+    line = ser.readline()
+
+    print "> " + line
+
+    try:
+        # parse it
+        p = xml.parsers.expat.ParserCreate()
+        p.StartElementHandler = start_element
+        p.EndElementHandler = end_element
+        p.CharacterDataHandler = char_data
+        p.Parse(line, 1)
+
+    except xml.parsers.expat.ExpatError:
+        print("Received incomplete data from CurrentCost meter. Will try and get a new reading")
+    
+    except serial.SerialException, err:
+        print("Failed to receive data from CurrentCost meter :: " + str(err))
+        ser.close()
+        exit(1)
+
+# finished with serial port - close it
+ser.close()
+
+# store it
+ccfuncs.ParseCurrentCostXML(ccdb, newupd)
+
+
+exit(0)