Merge branch 'restframework2' of https://github.com/tomchristie/django-rest-framework into restframework2

1 files changed, 80 insertions, 0 deletions

diff --git a/rest_framework/pagination.py b/rest_framework/pagination.py
new file mode 100644
index 00000000..131718fd
--- /dev/null
+++ b/rest_framework/pagination.py
@@ -0,0 +1,80 @@
+from rest_framework import serializers
+
+# TODO: Support URLconf kwarg-style paging
+
+
+class NextPageField(serializers.Field):
+    """
+    Field that returns a link to the next page in paginated results.
+    """
+    def to_native(self, value):
+        if not value.has_next():
+            return None
+        page = value.next_page_number()
+        request = self.context.get('request')
+        relative_url = '?page=%d' % page
+        if request:
+            return request.build_absolute_uri(relative_url)
+        return relative_url
+
+
+class PreviousPageField(serializers.Field):
+    """
+    Field that returns a link to the previous page in paginated results.
+    """
+    def to_native(self, value):
+        if not value.has_previous():
+            return None
+        page = value.previous_page_number()
+        request = self.context.get('request')
+        relative_url = '?page=%d' % page
+        if request:
+            return request.build_absolute_uri('?page=%d' % page)
+        return relative_url
+
+
+class PaginationSerializerOptions(serializers.SerializerOptions):
+    """
+    An object that stores the options that may be provided to a
+    pagination serializer by using the inner `Meta` class.
+
+    Accessible on the instance as `serializer.opts`.
+    """
+    def __init__(self, meta):
+        super(PaginationSerializerOptions, self).__init__(meta)
+        self.object_serializer_class = getattr(meta, 'object_serializer_class',
+                                               serializers.Field)
+
+
+class BasePaginationSerializer(serializers.Serializer):
+    """
+    A base class for pagination serializers to inherit from,
+    to make implementing custom serializers more easy.
+    """
+    _options_class = PaginationSerializerOptions
+    results_field = 'results'
+
+    def __init__(self, *args, **kwargs):
+        """
+        Override init to add in the object serializer field on-the-fly.
+        """
+        super(BasePaginationSerializer, self).__init__(*args, **kwargs)
+        results_field = self.results_field
+        object_serializer = self.opts.object_serializer_class
+        self.fields[results_field] = object_serializer(source='object_list')
+
+    def to_native(self, obj):
+        """
+        Prevent default behaviour of iterating over elements, and serializing
+        each in turn.
+        """
+        return self.convert_object(obj)
+
+
+class PaginationSerializer(BasePaginationSerializer):
+    """
+    A default implementation of a pagination serializer.
+    """
+    count = serializers.Field(source='paginator.count')
+    next = NextPageField(source='*')
+    previous = PreviousPageField(source='*')