Merge pull request #9 from colibris-framework/pagination

Pagination

colibris/pagination.py

@@ -0,0 +1,47 @@
+import math
+
+from colibris.api.envelope import wrap_many
+from marshmallow.validate import Range
+
+from colibris import api
+from colibris.schemas import fields, Schema, ValidationError
+
+page_validator = Range(min=1, error='Value must be greater than 0.')
+
+
+class PageNumberPagination:
+    PAGE_SIZE = 25
+    PAGE_SIZE_QUERY_PARAM = 'page_size'
+    PAGE_QUERY_PARAM = 'page'
+
+    _query_schema = type('PaginationQuerySchema', (Schema,), {
+        PAGE_SIZE_QUERY_PARAM: fields.Integer(missing=PAGE_SIZE, validate=page_validator),
+        PAGE_QUERY_PARAM: fields.Integer(missing=1, validate=page_validator)
+    })()
+
+    def __init__(self, query, request):
+        self.query = query
+        self.request = request
+
+        try:
+            query_params = self._query_schema.load(self.request.query)
+        except ValidationError as err:
+            raise api.SchemaError(details=err.messages)
+
+        self.page = query_params[self.PAGE_QUERY_PARAM]
+        self.page_size = query_params[self.PAGE_SIZE_QUERY_PARAM]
+
+    def paginate_query(self):
+        return self.query.paginate(self.page, self.page_size)
+
+    def get_enveloped_data(self, data):
+        count = self.query.count()
+        pages = math.ceil(count / self.page_size)
+
+        return wrap_many(
+            objs=data,
+            count=count,
+            page=self.page,
+            pages=pages,
+            page_size=self.page_size
+        )

colibris/schemas/base.py

@@ -23,14 +23,6 @@ def __init__(self, meta, **kwargs):
 class ModelSchema(marshmallow_peewee.ModelSchema):
     OPTIONS_CLASS = ModelSchemaOpts
 
-    @post_dump(pass_many=True)
-    def wrap(self, data, many, **kwargs):
-        if many:
-            return envelope.wrap_many(data)
-
-        else:
-            return envelope.wrap_one(data)
-
     @post_load
     def make_instance(self, data, **kwargs):
         if not self.opts.load_instance:

colibris/views/api.py

@@ -9,7 +9,7 @@ class APIView(View):
     body_schema_class = None
     query_schema_class = None
 
-    def get_body_schema_class(self, *args, **kwargs):
+    def get_body_schema(self, *args, **kwargs):
         assert self.body_schema_class is not None, 'The attribute "body_schema_class" is required for {}'.format(self)
 
         kwargs.update({
@@ -20,7 +20,7 @@ def get_body_schema_class(self, *args, **kwargs):
 
         return schema
 
-    def get_query_schema_class(self, *args, **kwargs):
+    def get_query_schema(self, *args, **kwargs):
         assert self.query_schema_class is not None, 'The attribute "query_schema_class" is required for {}'.format(self)
 
         kwargs.update({
@@ -33,7 +33,7 @@ def get_query_schema_class(self, *args, **kwargs):
 
     async def get_validated_body(self, schema=None):
         if schema is None:
-            schema = self.get_body_schema_class()
+            schema = self.get_body_schema()
 
         json_payload = await self.get_request_payload()
 
@@ -57,7 +57,7 @@ async def get_request_payload(self):
 
     async def get_validated_query(self, schema=None):
         if schema is None:
-            schema = self.get_query_schema_class()
+            schema = self.get_query_schema()
 
         query = await self.get_request_query()
 

colibris/views/mixins.py

@@ -40,17 +40,29 @@ def __init__(cls, name, bases, attrs):
 
 class ListMixin(metaclass=_GenericMixinMeta):
     async def get(self):
-        items = self.get_query()
-        schema = self.get_body_schema_class(many=True)
-        result = schema.dump(list(items))
+        query = self.get_query()
+        schema = self.get_body_schema(many=True)
+
+        if self.pagination_class is not None:
+            return await self._get_paginated_response(query, schema)
+
+        result = schema.dump(list(query))
 
         return web.json_response(result)
 
+    async def _get_paginated_response(self, query, schema):
+        paginator = self.pagination_class(query, self.request)
+        paginated_query = paginator.paginate_query()
+        result = schema.dump(list(paginated_query))
+        paginated_result = paginator.get_enveloped_data(result)
+
+        return web.json_response(paginated_result)
+
 
 class CreateMixin(metaclass=_GenericMixinMeta):
     async def post(self):
         query = self.get_query()
-        schema = self.get_body_schema_class()
+        schema = self.get_body_schema()
         data = await self.get_validated_body(schema)
 
         instance = query.model.create(**data)
@@ -70,7 +82,7 @@ async def put(self):
     async def _update(self, partial):
         instance = self.get_object()
 
-        schema = self.get_body_schema_class(partial=partial, instance=instance)
+        schema = self.get_body_schema(partial=partial, instance=instance)
         data = await self.get_validated_body(schema)
 
         instance.update_fields(data)
@@ -91,7 +103,7 @@ async def delete(self):
 
 class RetrieveMixin(metaclass=_GenericMixinMeta):
     async def get(self):
-        schema = self.get_body_schema_class()
+        schema = self.get_body_schema()
         instance = self.get_object()
 
         result = schema.dump(instance)

colibris/views/model.py

@@ -4,7 +4,7 @@
 
 class ModelView(APIView):
     model = None
-    body_schema_class = None
+    pagination_class = None
     url_identifier = 'id'
     lookup_field = 'id'