Add MasterView.render() method for sake of common context/logic

That still needs some work I'm sure...

tailbone/views/master.py

@@ -35,7 +35,7 @@ from edbob.util import prettify
 
 import formalchemy
 from pyramid import httpexceptions
-from pyramid.renderers import get_renderer, render_to_response
+from pyramid.renderers import get_renderer, render_to_response, render
 
 from tailbone import forms
 from tailbone.views import View
@@ -387,6 +387,42 @@ class MasterView(View):
             return render_to_response('{}/{}.mako'.format(self.get_template_prefix(), template),
                                       context, request=self.request)
 
+    # TODO: merge this logic with render_to_response()
+    def render(self, template, data):
+        """
+        Render the given template with the given context data.
+        """
+        context = {
+            'master': self,
+            'model_title': self.get_model_title(),
+            'model_title_plural': self.get_model_title_plural(),
+            'route_prefix': self.get_route_prefix(),
+            'permission_prefix': self.get_permission_prefix(),
+            'index_title': self.get_index_title(),
+            'index_url': self.get_index_url(),
+            'action_url': self.get_action_url,
+        }
+        context.update(data)
+
+        # First try the template path most specific to the view.
+        try:
+            return render('{}/{}.mako'.format(self.get_template_prefix(), template),
+                          context, request=self.request)
+
+        except IOError:
+
+            # Failing that, try one or more fallback templates.
+            for fallback in self.get_fallback_templates(template):
+                try:
+                    return render(fallback, context, request=self.request)
+                except IOError:
+                    pass
+
+            # If we made it all the way here, we found no templates at all, in
+            # which case re-attempt the first and let that error raise on up.
+            return render('{}/{}.mako'.format(self.get_template_prefix(), template),
+                          context, request=self.request)
+
     def get_fallback_templates(self, template):
         return ['/master/{}.mako'.format(template)]