diff --git a/interfaces.py b/interfaces.py
new file mode 100644
index 0000000..ff203cf
--- /dev/null
+++ b/interfaces.py
@@ -0,0 +1,3 @@
+# scopes.interfaces
+
+
diff --git a/scopes/interfaces.py b/scopes/interfaces.py
new file mode 100644
index 0000000..8d1eef1
--- /dev/null
+++ b/scopes/interfaces.py
@@ -0,0 +1,24 @@
+# scopes.interfaces
+
+from zope.interface import Interface
+
+
+class ITraversable(Interface):
+
+    def items():
+        """Return a sequence of key, value pairs of child objects."""
+
+    def keys():
+        """Return a sequence of keys of child objects."""
+
+    def get(key, default):
+        """Return the item addressed by `key`; return `default` if not found."""
+
+    def __getitem__(key):
+        """Return the item addressed by `key`; rais KeyError if not found."""
+
+    def __setitem__(key, value):
+        """Store the `value` under the `key`. 
+
+        May modify `value` so that the attributes referencing this object
+        and the value object (e.g. `parent´ and `name`) are stored correctly."""
diff --git a/scopes/server/app.py b/scopes/server/app.py
index 706bbae..1ed9223 100644
--- a/scopes/server/app.py
+++ b/scopes/server/app.py
@@ -8,47 +8,21 @@ from zope.traversing.publicationtraverse import PublicationTraverser
 from scopes.storage.folder import Root
 
 
-def demo_app(environ, start_response):
-    print(f'*** environ {environ}.')
-    status = '200 OK'
-    headers = [("Content-type", "text/plain; charset=utf-8")]
-    start_response(status, headers)
-    return ['Hello World'.encode()]
-
-
 def zope_app_factory(config):
-    config.storageFactory = config.StorageFactory(config)
+    storageFactory = config.StorageFactory(config)
     def zope_app(environ, start_response):
-        request = BrowserRequest(environ['wsgi.input'], environ)
-        storage = config.storageFactory(config.dbschema)
+        storage = storageFactory(config.dbschema)
         appRoot = Root(storage, config)
-        request.setPublication(DefaultPublication(appRoot))
-        request = publish(request, False)
+        request = BrowserRequest(environ['wsgi.input'], environ)
+        request.setPublication(Publication(appRoot))
+        request = publish(request, True)
         response = request.response
         start_response(response.getStatusString(), response.getHeaders())
         return response.consumeBodyIter()
     return zope_app
 
 
-class AppRoot:
-    """Zope Demo AppRoot"""
-
-    def __init__(self, config):
-        self.config = config
-
-    def __call__(self):
-        """calling AppRoot"""
-        return 'At root'
-
-    def __getitem__(self, key):
-        def child():
-            """get child"""
-            print(f'--- getitem {key}')
-            return 'getitem'
-        return child
-
-    def hello(self): 
-        """method hello"""
-        return 'Hello AppRoot'
+class Publication(DefaultPublication):
 
+    pass
 
diff --git a/scopes/storage/folder.py b/scopes/storage/folder.py
index 9c3463e..961294a 100644
--- a/scopes/storage/folder.py
+++ b/scopes/storage/folder.py
@@ -10,9 +10,11 @@ class Folder(Track):
     headFields = ['parent', 'name', 'ref']
     prefix = 'fldr'
 
+    def items(self):
+        return ((f.name, f) for f in self.container.query(parent=self.rid))
+
     def keys(self):
-        for f in self.container.query(parent=self.rid):
-            yield f.name
+        return (k for k, v in self.items())
 
     def get(self, key, default=None):
         value = self.container.queryLast(parent=self.rid, name=key)