Allow for ObjectFields to call prepare_func included in InnerDoc. (django-es#346)

* Allow for ObjectFields to call prepare_funcs from elasticsearch_dsl.InnerDoc

* Minor cleanup for from PR review

Author: paulogiacomelli

django_elasticsearch_dsl/fields.py

@@ -115,9 +115,16 @@ def _get_inner_field_data(self, obj, field_value_to_ignore=None):
                 if field._path == []:
                     field._path = [name]
 
-                data[name] = field.get_value_from_instance(
-                    obj, field_value_to_ignore
-                )
+                # This allows for retrieving data from an InnerDoc with prepare_field_name functions.
+                doc_instance = self._doc_class()
+                prep_func = getattr(doc_instance, 'prepare_%s' % name, None)
+
+                if prep_func:
+                    data[name] = prep_func(obj)
+                else:
+                    data[name] = field.get_value_from_instance(
+                        obj, field_value_to_ignore
+                    )
 
         # This allows for ObjectFields to be indexed from dicts with
         # dynamic keys (i.e. keys/fields not defined in 'properties')

tests/test_documents.py

@@ -3,7 +3,7 @@
 
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
-from elasticsearch_dsl import GeoPoint, MetaField
+from elasticsearch_dsl import GeoPoint, MetaField, InnerDoc
 from mock import patch, Mock, PropertyMock
 
 from django_elasticsearch_dsl import fields
@@ -173,6 +173,43 @@ def test_prepare(self):
             }
         )
 
+    def test_innerdoc_prepare(self):
+        class ManufacturerInnerDoc(InnerDoc):
+            name = fields.TextField()
+            location = fields.TextField()
+
+            def prepare_location(self, instance):
+                return "USA"
+
+        @registry.register_document
+        class CarDocumentWithInnerDoc(DocType):
+            manufacturer = fields.ObjectField(doc_class=ManufacturerInnerDoc)
+
+            class Django:
+                model = Car
+                fields = ['name', 'price']
+
+            class Index:
+                name = 'car_index'
+
+        manufacturer = Manufacturer(
+            name="Bugatti",
+        )
+
+        car = Car(name="Type 57", price=5400000.0, manufacturer=manufacturer)
+        doc = CarDocumentWithInnerDoc()
+        prepared_data = doc.prepare(car)
+        self.assertEqual(
+            prepared_data, {
+                'name': car.name,
+                'price': car.price,
+                'manufacturer': {
+                    'name': car.manufacturer.name,
+                    'location': ManufacturerInnerDoc().prepare_location(manufacturer)
+                }
+            }
+        )
+
     def test_prepare_ignore_dsl_base_field(self):
         @registry.register_document
         class CarDocumentDSlBaseField(DocType):