BaseChart Changes to Allow Browser Config from the Server.

A number of browser configuration options will now be controlled by
server code through use of data attributes in the chart selection option
elements.  This commit makes the necessary changes to the BaseChart
object.

bmsapp/reports/basechart.py

@@ -99,6 +99,36 @@ class BaseChart(object):
     """Base class for all of the chart classes.
     """
 
+    # Constants to override, if needed for the specific chart being created.
+    # These constants affect configuration of the browser user interface that 
+    # will be used for this particular chart.
+
+    # This is a comma-separated list of the client HTML controls that need to be
+    # visible for this chart.
+    CTRLS = 'ctrl_sensor, time_period'
+
+    # 1 if the Sensor selection control should allow for selecting more than one
+    # sensor.
+    MULTI_SENSOR = 0
+
+    # 1 if the chart should automatically recalculate and refresh when the user 
+    # changes inputs.
+    AUTO_RECALC = 1
+
+    # 1 if the chart should automatically refresh every 10 minutes even without 
+    # changes in user inputs
+    TIMED_REFRESH = 0
+
+    @classmethod
+    def data_attributes(cls):
+        '''This class method returns an string of HTML data attributes that will
+        control aspects of the browser user interface.  Javascript in the browser
+        reads these attributes and configures the interface appropriately.
+        '''
+        return 'data-ctrls="%s" data-multi_sensor="%s" data-auto_recalc="%s" data-timed_refresh="%s"' % \
+            (cls.CTRLS, cls.MULTI_SENSOR, cls.AUTO_RECALC, cls.TIMED_REFRESH)
+
+
     def __init__(self, chart_info, bldg_id, request_params):
         """
         'chart_info' is the models.MultiBuildingChart object for the chart if it