Merged BaseSerializer with WagtailSerializer

Previously, WagtailSerializer and it's subclasses were responsible for serializing objects and it delegated serializing the dynamic fields to automatically generated subclasses of BaseSerializer.

Now, these have been merged and all serializers are generated automatically for a particular request. The responsibility of generating the serializers is now in the endpoint.

wagtail/contrib/wagtailapi/endpoints.py

@@ -20,14 +20,14 @@ from .filters import (
 )
 from .renderers import WagtailJSONRenderer
 from .pagination import WagtailPagination
-from .serializers import WagtailSerializer, PageSerializer, DocumentSerializer
+from .serializers import BaseSerializer, PageSerializer, DocumentSerializer, get_serializer_class
 from .utils import BadRequestError
 
 
 class BaseAPIEndpoint(GenericViewSet):
     renderer_classes = [WagtailJSONRenderer]
     pagination_class = WagtailPagination
-    serializer_class = WagtailSerializer
+    base_serializer_class = BaseSerializer
     filter_classes = []
     queryset = None  # Set on subclasses or implement `get_queryset()`.
 
@@ -87,18 +87,21 @@ class BaseAPIEndpoint(GenericViewSet):
         if unknown_parameters:
             raise BadRequestError("query parameter is not an operation or a recognised field: %s" % ', '.join(sorted(unknown_parameters)))
 
-    def get_serializer_context(self):
-        """
-        The serialization context differs between listing and detail views.
-        """
+    def get_serializer_class(self):
         request = self.request
 
+        # Get model
         if self.action == 'listing_view':
             model = self.get_queryset().model
+        else:
+            model = type(self.get_object())
 
-            all_fields = self.get_api_fields(model)
-            all_fields = list(OrderedDict.fromkeys(all_fields)) # Removes any duplicates in case the developer put "title" in api_fields
+        # Get all available fields
+        all_fields = self.get_api_fields(model)
+        all_fields = list(OrderedDict.fromkeys(all_fields)) # Removes any duplicates in case the developer put "title" in api_fields
 
+        if self.action == 'listing_view':
+            # Listing views just show the title field and any other allowed field the user specified
             if 'fields' in request.GET:
                 fields = set(request.GET['fields'].split(','))
             else:
@@ -111,22 +114,27 @@ class BaseAPIEndpoint(GenericViewSet):
 
             # Reorder fields so it matches the order of all_fields
             fields = [field for field in all_fields if field in fields]
+        else:
+            # Detail views show all fields all the time
+            fields = all_fields
 
+        return get_serializer_class(model, fields, base=self.base_serializer_class)
+
+    def get_serializer_context(self):
+        """
+        The serialization context differs between listing and detail views.
+        """
+        request = self.request
+
+        if self.action == 'listing_view':
             return {
                 'request': request,
                 'view': self,
-                'fields': fields
             }
 
-        model = type(self.get_object())
-
-        all_fields = self.get_api_fields(model)
-        all_fields = list(OrderedDict.fromkeys(all_fields)) # Removes any duplicates in case the developer put "title" in api_fields
-
         return {
             'request': request,
             'view': self,
-            'fields': all_fields,
             'show_details': True
         }
 
@@ -155,7 +163,7 @@ class BaseAPIEndpoint(GenericViewSet):
 
 
 class PagesAPIEndpoint(BaseAPIEndpoint):
-    serializer_class = PageSerializer
+    base_serializer_class = PageSerializer
     filter_backends = [
         FieldsFilter,
         ChildOfFilter,
@@ -216,7 +224,7 @@ class ImagesAPIEndpoint(BaseAPIEndpoint):
 
 class DocumentsAPIEndpoint(BaseAPIEndpoint):
     queryset = Document.objects.all().order_by('id')
-    serializer_class = DocumentSerializer
+    base_serializer_class = DocumentSerializer
     filter_backends = [FieldsFilter, OrderingFilter, SearchFilter]
     extra_api_fields = ['title', 'tags']
     name = 'documents'

wagtail/contrib/wagtailapi/serializers.py

@@ -14,7 +14,7 @@ from wagtail.utils.compat import get_related_model
 from wagtail.wagtailcore.models import Page
 from wagtail.wagtailcore import fields as wagtailcore_fields
 
-from .utils import ObjectDetailURL, URLPath, BadRequestError, pages_for_site
+from .utils import ObjectDetailURL, URLPath, pages_for_site
 
 
 class ChildRelationField(Field):
@@ -27,7 +27,8 @@ class ChildRelationField(Field):
         serializer = serializer_class()
 
         return [
-            serializer.to_representation(child_object)
+            # Use rest frameworks to_representation method so we don't add id/meta attributes
+            super(BaseSerializer, serializer).to_representation(child_object)
             for child_object in value.all()
         ]
 
@@ -88,24 +89,8 @@ class BaseSerializer(serializers.ModelSerializer):
 
         return super(BaseSerializer, self).build_relational_field(field_name, relation_info)
 
-
-def get_serializer_class(model_, fields_):
-    class Meta:
-        model = model_
-        fields = fields_
-
-    return type(model_.__name__ + 'Serializer', (BaseSerializer, ), {
-        'Meta': Meta
-    })
-
-
-class WagtailSerializer(serializers.BaseSerializer):
     def to_representation(self, instance):
-        fields = self.context.get('fields')
-        return self.serialize_object(
-            instance,
-            fields=fields,
-        )
+        return self.serialize_object(instance)
 
     def serialize_object_metadata(self, obj):
         """
@@ -120,7 +105,7 @@ class WagtailSerializer(serializers.BaseSerializer):
 
         return data
 
-    def serialize_object(self, obj, fields, extra_data=()):
+    def serialize_object(self, obj, extra_data=()):
         """
         This converts an object into JSON-serialisable dict so it can
         be used in the API.
@@ -138,14 +123,12 @@ class WagtailSerializer(serializers.BaseSerializer):
         data.extend(extra_data)
 
         # Serialize the fields
-        serializer_class = get_serializer_class(type(obj), fields)
-        serializer = serializer_class()
-        data.extend(serializer.to_representation(obj).items())
+        data.extend(super(BaseSerializer, self).to_representation(obj).items())
 
         return OrderedDict(data)
 
 
-class PageSerializer(WagtailSerializer):
+class PageSerializer(BaseSerializer):
     def serialize_object_metadata(self, page):
         data = super(PageSerializer, self).serialize_object_metadata(page)
 
@@ -154,7 +137,7 @@ class PageSerializer(WagtailSerializer):
 
         return data
 
-    def serialize_object(self, page, fields, extra_data=()):
+    def serialize_object(self, page, extra_data=()):
         # Add parent
         if self.context.get('show_details', False):
             parent = page.get_parent()
@@ -173,10 +156,10 @@ class PageSerializer(WagtailSerializer):
                     ])),
                 )
 
-        return super(PageSerializer, self).serialize_object(page, fields, extra_data=extra_data)
+        return super(PageSerializer, self).serialize_object(page, extra_data=extra_data)
 
 
-class DocumentSerializer(WagtailSerializer):
+class DocumentSerializer(BaseSerializer):
     def serialize_object_metadata(self, document):
         data = super(DocumentSerializer, self).serialize_object_metadata(document)
 
@@ -185,3 +168,13 @@ class DocumentSerializer(WagtailSerializer):
             data['download_url'] = URLPath(document.url)
 
         return data
+
+
+def get_serializer_class(model_, fields_, base=BaseSerializer):
+    class Meta:
+        model = model_
+        fields = fields_
+
+    return type(model_.__name__ + 'Serializer', (base, ), {
+        'Meta': Meta
+    })