Optional count of total number of pages

flask_sqlalchemy/__init__.py

@@ -325,7 +325,7 @@ def __init__(self, query, page, per_page, total, items):
     @property
     def pages(self):
         """The total number of pages"""
-        if self.per_page == 0:
+        if self.per_page == 0 or self.total is None:
             pages = 0
         else:
             pages = int(ceil(self.total / float(self.per_page)))
@@ -427,13 +427,14 @@ def first_or_404(self):
             abort(404)
         return rv
 
-    def paginate(self, page=None, per_page=None, error_out=True, max_per_page=None):
+    def paginate(self, page=None, per_page=None, error_out=True, max_per_page=None, count=True):
         """Returns ``per_page`` items from page ``page``.
 
         If ``page`` or ``per_page`` are ``None``, they will be retrieved from
         the request query. If ``max_per_page`` is specified, ``per_page`` will
         be limited to that value. If there is no request or they aren't in the
-        query, they default to 1 and 20 respectively.
+        query, they default to 1 and 20 respectively. If ``count`` is ``False``,
+        no query to help determine total page count will be run.
 
         When ``error_out`` is ``True`` (default), the following rules will
         cause a 404 response:
@@ -494,8 +495,11 @@ def paginate(self, page=None, per_page=None, error_out=True, max_per_page=None):
             abort(404)
 
         # No need to count if we're on the first page and there are fewer
-        # items than we expected.
-        if page == 1 and len(items) < per_page:
+        # items than we expected or if count is disabled.
+
+        if not count:
+            total = None
+        elif page == 1 and len(items) < per_page:
             total = len(items)
         else:
             total = self.order_by(None).count()

tests/test_pagination.py

@@ -22,6 +22,11 @@ def test_pagination_pages_when_0_items_per_page():
     assert p.pages == 0
 
 
+def test_pagination_pages_when_total_is_none():
+    p = fsa.Pagination(None, 1, 100, None, [])
+    assert p.pages == 0
+
+
 def test_query_paginate(app, db, Todo):
     with app.app_context():
         db.session.add_all([Todo('', '') for _ in range(100)])
@@ -68,3 +73,11 @@ def test_paginate_min(app, db, Todo):
 
     with pytest.raises(NotFound):
         Todo.query.paginate(per_page=-1)
+
+
+def test_paginate_without_count(app, db, Todo):
+    with app.app_context():
+        db.session.add_all(Todo('', '') for _ in range(20))
+        db.session.commit()
+
+    assert len(Todo.query.paginate(count=False, page=1, per_page=10).items) == 10