From a5b6568179b9b17b2dd14b43bcccded15bf5025d Mon Sep 17 00:00:00 2001
From: Aurélien Bompard
Date: Wed, 4 Nov 2015 11:33:07 +0100
Subject: Rework pagination to fix the 'start' and 'total_size' values

---
 src/mailman/rest/helpers.py | 59 +++++++++++++++++++--------------------------
 1 file changed, 25 insertions(+), 34 deletions(-)

(limited to 'src/mailman/rest/helpers.py')

diff --git a/src/mailman/rest/helpers.py b/src/mailman/rest/helpers.py
index 0bba86521..a78f5b379 100644
--- a/src/mailman/rest/helpers.py
+++ b/src/mailman/rest/helpers.py
@@ -114,31 +114,6 @@ 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 in the request
-    itself.  The request should use query parameters `count` and `page` to
-    specify the slice they want.  The slice will start at index
-    ``(page - 1) * count`` and end (exclusive) at ``(page * count)``.
-
-    Decorated methods must take ``self`` and ``request`` as the first two
-    arguments.
-    """
-    def wrapper(self, request, *args, **kwargs):
-        # Allow falcon's HTTPBadRequest exceptions to percolate up.  They'll
-        # get turned into HTTP 400 errors.
-        count = request.get_param_as_int('count', min=0)
-        page = request.get_param_as_int('page', min=1)
-        result = method(self, request, *args, **kwargs)
-        if count is None and page is None:
-            return result
-        list_start = (page - 1) * count
-        list_end = page * count
-        return result[list_start:list_end]
-    return wrapper
-
-
 
 class CollectionMixin:
     """Mixin class for common collection-ish things."""
@@ -170,22 +145,38 @@ class CollectionMixin:
         """
         raise NotImplementedError
 
+    def _paginate(self, request, collection):
+        """Method to paginate through collection result lists.
+
+        Use this to return only a slice of a collection, specified in the request
+        itself.  The request should use query parameters `count` and `page` to
+        specify the slice they want.  The slice will start at index
+        ``(page - 1) * count`` and end (exclusive) at ``(page * count)``.
+        """
+        # Allow falcon's HTTPBadRequest exceptions to percolate up.  They'll
+        # get turned into HTTP 400 errors.
+        count = request.get_param_as_int('count', min=0)
+        page = request.get_param_as_int('page', min=1)
+        total_size = len(collection)
+        if count is None and page is None:
+            return 0, total_size, collection
+        list_start = (page - 1) * count
+        list_end = page * count
+        return list_start, total_size, collection[list_start:list_end]
+
     def _make_collection(self, request):
         """Provide the collection to the REST layer."""
-        collection = self._get_collection(request)
-        if len(collection) == 0:
-            return dict(start=0, total_size=0)
-        else:
+        start, total_size, collection = self._paginate(
+            request, self._get_collection(request))
+        result = dict(start=start, total_size=total_size)
+        if len(collection) != 0:
             entries = [self._resource_as_dict(resource)
                        for resource in collection]
             # Tag the resources but use the dictionaries.
             [etag(resource) for resource in entries]
             # Create the collection resource
-            return dict(
-                start=0,
-                total_size=len(collection),
-                entries=entries,
-                )
+            result['entries'] = entries
+        return result
 
     def path_to(self, resource):
         return path_to(resource, self.api_version)
-- 
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