initial version

Change-Id: I699e0ab082657880998d8618fe29eb7f56c6c661

watcher/api/controllers/v1/collection.py

@@ -0,0 +1,50 @@
+# -*- encoding: utf-8 -*-
+# Copyright 2013 Red Hat, Inc.
+# All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import pecan
+from wsme import types as wtypes
+
+from watcher.api.controllers import base
+from watcher.api.controllers import link
+
+
+class Collection(base.APIBase):
+
+    next = wtypes.text
+    """A link to retrieve the next subset of the collection"""
+
+    @property
+    def collection(self):
+        return getattr(self, self._type)
+
+    def has_next(self, limit):
+        """Return whether collection has more items."""
+        return len(self.collection) and len(self.collection) == limit
+
+    def get_next(self, limit, url=None, **kwargs):
+        """Return a link to the next subset of the collection."""
+        if not self.has_next(limit):
+            return wtypes.Unset
+
+        resource_url = url or self._type
+        q_args = ''.join(['%s=%s&' % (key, kwargs[key]) for key in kwargs])
+        next_args = '?%(args)slimit=%(limit)d&marker=%(marker)s' % {
+            'args': q_args, 'limit': limit,
+            'marker': self.collection[-1].uuid}
+
+        return link.Link.make_link('next', pecan.request.host_url,
+                                   resource_url, next_args).href