1 files changed, 41 insertions, 0 deletions

diff --git a/src/mailman/rest/helpers.py b/src/mailman/rest/helpers.py
index 197e74362..3b64dc0dc 100644
--- a/src/mailman/rest/helpers.py
+++ b/src/mailman/rest/helpers.py
@@ -38,8 +38,10 @@ from cStringIO import StringIO
 from datetime import datetime, timedelta
 from flufl.enum import Enum
 from lazr.config import as_boolean
+from restish import http
 from restish.http import Response
 from restish.resource import MethodDecorator
+from urllib2 import HTTPError
 from webob.multidict import MultiDict
 
 from mailman.config import config
@@ -105,6 +107,45 @@ def etag(resource):
     return json.dumps(resource, cls=ExtendedEncoder)
 
 
+def paginate(method):
+    """Method decorator to paginate through collection result lists.
+
+    Use this to return only a slice of a collection, specified either
+    in the request itself or by the ``default_count`` argument.
+    ``default_count=None`` will return the whole collection if the request
+    contains no count/page parameters.
+
+    :param default_count: The default page length if no count is specified.
+    :type default_count: int
+    :returns: Decorator function.
+    """
+    def wrapper(*args, **kwargs):
+        # args[0] is self.
+        # restish Request object is expected to be the second arg.
+        request = args[1]
+        # get the result
+        result = method(*args, **kwargs)
+        try:
+            count = int(request.GET['count'])
+            page = int(request.GET['page'])
+            # Set indices
+            list_start = 0
+            list_end = None
+            # slice list only if count is not None
+            if count is not None:
+                list_start = int((page - 1) * count)
+                list_end = int(page * count)
+                return result[list_start:list_end]
+        # Wrong parameter types or no GET attribute in request object.
+        except (AttributeError, ValueError, TypeError):
+            return http.bad_request([], b'Invalid parameters')
+        # No count/page params
+        except KeyError:
+            pass
+        return result
+    return wrapper
+
+
 
 class CollectionMixin:
     """Mixin class for common collection-ish things."""