Let subclass of MasterView override the database Session it uses.

tailbone/views/master.py

@@ -35,7 +35,6 @@ import formalchemy
 from pyramid.renderers import get_renderer, render_to_response
 from pyramid.httpexceptions import HTTPFound, HTTPNotFound
 
-from tailbone.db import Session
 from tailbone.views import View
 from tailbone.newgrids import filters, AlchemyGrid, GridAction
 from tailbone.forms import AlchemyForm
@@ -58,6 +57,15 @@ class MasterView(View):
     row_attrs = {}
     cell_attrs = {}
 
+    @property
+    def Session(self):
+        """
+        SQLAlchemy scoped session to use when querying the database.  Defaults
+        to ``tailbone.db.Session``.
+        """
+        from tailbone.db import Session
+        return Session
+
     ##############################
     # Available Views
     ##############################
@@ -413,7 +421,7 @@ class MasterView(View):
         override this method; override :meth:`query()` instead.
         """
         if session is None:
-            session = Session()
+            session = self.Session()
         return self.query(session)
 
     def query(self, session):
@@ -453,7 +461,7 @@ class MasterView(View):
         doing a database lookup.  If the instance cannot be found, raises 404.
         """
         key = self.request.matchdict[self.get_model_key()]
-        instance = Session.query(self.model_class).get(key)
+        instance = self.Session.query(self.model_class).get(key)
         if not instance:
             raise HTTPNotFound()
         return instance
@@ -484,7 +492,7 @@ class MasterView(View):
         """
         Make a FormAlchemy fieldset for the given model instance.
         """
-        kwargs.setdefault('session', Session())
+        kwargs.setdefault('session', self.Session())
         kwargs.setdefault('request', self.request)
         fieldset = formalchemy.FieldSet(instance, **kwargs)
         fieldset.prettify = prettify
@@ -525,8 +533,8 @@ class MasterView(View):
         """
         # Flush immediately to force any pending integrity errors etc.; that
         # way we don't set flash message until we know we have success.
-        Session.delete(instance)
-        Session.flush()
+        self.Session.delete(instance)
+        self.Session.flush()
 
     def get_after_delete_url(self, instance):
         """