created MultipleChartsView

statistiques/charts.py

@@ -1,61 +1,88 @@
-from django.db.models import (Field, CharField, NullBooleanField,
+from django.db.models import (Field, NullBooleanField,
                               Count,
                               )
 from graphos.sources.simple import SimpleDataSource
 from graphos.renderers import gchart
 
+# Defines generic labels for common fields
+LABELS = {
+        NullBooleanField: {True: "Oui", False: "Non", None:"Ne sait pas"},
+    }
+
+class FieldValuesCountDataSource(SimpleDataSource):
+    """ Generates data from a limited set of choices.
+
+    """
+    def __init__(self, queryset, field, labels=None, excluded=[]):
+        self.queryset = queryset
+        self.field_name = field.name
+        self.excluded = excluded
+        if not labels:
+            if field.__class__ in LABELS:
+                labels = LABELS[field.__class__]
+            elif field.choices:
+                labels = dict(field.choices)
+            else:
+                raise ValueError("Could not retrieve labels for", field)
+        self.labels = labels
+        super().__init__(self.create_data())
+
+    def create_data(self):
+        data = [(self.field_name, "%s_count" % self.field_name)]  # Headers
+        data += [
+            (self.labels[item[self.field_name]],  # Display a label instead of raw values
+             item['count']
+             ) for item in self.queryset.values(            # Retrieve all values for field
+                                            self.field_name
+                                        ).annotate(         # Count occurrences of each value
+                                            count=Count('pk')
+                                        ).order_by()        # Needed so that counts are aggregated
+            # Exclude values that are marked to be ignored
+            if (not self.excluded
+                or item[self.field_name] not in self.excluded)
+        ]
+        return data
+
 
 class PieWrapper(gchart.PieChart):
     """ A wrapper around gchart.PieChart that generates a graph from :
 
         - a queryset and a model field (NullBooleanField or field with choices)
+        OR
         - a data object and title
     """
 
     height=400
     width=800
-    labels = {
-        NullBooleanField: {True: "Oui", False: "Non", None:"Ne sait pas"},
-    }
 
-    def __init__(   self, queryset=None, field=None,
-                    data=None, title=None,
-                    null_values=[],**kwargs):
+    def __init__(self,
+                 queryset=None, field=None,
+                 data=None, title=None,
+                 null_values=[],
+                 **kwargs):
         if not data:
             if not isinstance(field, Field):
                 raise TypeError(field, 'must be a child of django.models.db.fields.Field !')
             if not queryset:
                 raise TypeError("You must give either a queryset and field or data")
-
-            if field.__class__ in PieWrapper.labels:
-                labels = PieWrapper.labels[field.__class__]
-            elif field.choices:
-                labels = dict(field.choices)
-            else:
-                raise ValueError("Could not guess labels for", field)
-
-            data = ([(field.name, 'count')] +  # Headers
-                [(labels[item[field.name]],
-                  item['nbr']) for item in queryset.values(
-                                                            field.name
-                                                        ).annotate(
-                                                            nbr=Count('pk')
-                                                        ).order_by()
-                    if (not null_values
-                        or item[field] not in null_values)
-                ])
+            data_source = FieldValuesCountDataSource(
+                queryset, field,
+                excluded=null_values,
+                labels=None  #TODO: How to pass in labels ??
+            )
+        else:
+            data_source = SimpleDataSource(data=data)
 
         super().__init__(
-            SimpleDataSource(
-                data=data
-                ),
+            data_source,
             options={
                 'title': getattr(field, 'verbose_name', title),
                 'is3D': True,
                 'pieSliceText': 'value',
                 'legend': {'position': 'labeled', 'maxLines': 3, 'textStyle': {'fontSize': 16,}},
                 },
-            width=kwargs.get('width', self.width), height=kwargs.get('height', self.height),
+            width=kwargs.get('width', self.width),
+            height=kwargs.get('height', self.height),
             )
 
     def get_js_template(self):