WCM-22: Support pagination in sql auto area queries

core/src/zeit/connector/interfaces.py

@@ -217,6 +217,12 @@ def query():
         Return query object for properties table
         """
 
+    def search_sql_count(search_expression):
+        """Count search results for `search_expression`
+
+        returns integer
+        """
+
 
 class ICachingConnector(IConnector):
     """A connector that caches."""

core/src/zeit/connector/mock.py

@@ -331,6 +331,9 @@ def search_sql(self, expression):
     def query(self):
         return sqlalchemy.select(self.Content)
 
+    def search_sql_count(self, query):
+        return len(self.search_result)
+
     # internal helpers
 
     def _get_cannonical_id(self, id):

core/src/zeit/connector/postgresql.py

@@ -601,6 +601,9 @@ def _search_dav(self, attrlist, expr):
     def query(self):
         return select(self.Content)
 
+    def search_sql_count(self, query):
+        return self.session.execute(query.with_only_columns(sqlalchemy.func.count())).scalar()
+
     def search_sql(self, query):
         result = []
         for content in self.session.execute(query).scalars():

core/src/zeit/connector/tests/test_postgresql.py

@@ -171,6 +171,14 @@ def test_search_by_sql_uses_cache(self):
         ):
             self.assertEqual(result[0].data.read(), b'mybody')
 
+    def test_search_sql_count_returns_result_count(self):
+        self.add_resource('one', type='article')
+        self.add_resource('two', type='centerpage')
+        self.add_resource('three', type='article')
+        query = self.connector.query()
+        query = query.filter_by(type='article')
+        self.assertEqual(self.connector.search_sql_count(query), 2)
+
     def test_search_returns_uuid(self):
         res = self.get_resource(
             'foo',

core/src/zeit/content/cp/tests/test_automatic.py

@@ -1154,3 +1154,7 @@ def test_offset_query_results_for_pagination(self):
         self.area.start = 5
         IRenderedArea(self.area).values()
         self.assertEllipsis('...OFFSET 5...', self.connector.search_args[0])
+
+    def test_get_total_hits(self):
+        self.connector.search_result = ['http://xml.zeit.de/testcontent']
+        self.assertEqual(1, IRenderedArea(self.area)._content_query.total_hits)

core/src/zeit/contentquery/query.py

@@ -56,17 +56,22 @@ class SQLContentQuery(ContentQuery):
     def connector(self):
         return zope.component.getUtility(zeit.connector.interfaces.IConnector)
 
+    @cachedproperty
+    def total_hits(self):
+        return self.connector.search_sql_count(self._build_query())
+
     def __call__(self):
-        result = [ICMSContent(x) for x in self.connector.search_sql(self._build_query())]
+        query = self._build_query()
+        query = query.order_by(sql(self.context.sql_order))
+        query = query.limit(self.rows).offset(self.start)
+        result = [ICMSContent(x) for x in self.connector.search_sql(query)]
         return result
 
     def _build_query(self):
         query = self.connector.query()
         query = query.where(sql(self.context.sql_query))
         query = self.add_clauses(query)
         query = self.hide_dupes_clause(query)
-        query = query.order_by(sql(self.context.sql_order))
-        query = query.limit(self.rows).offset(self.start)
 
         return query