Modernized docs in a few places

docs/appcontext.rst

@@ -82,7 +82,9 @@ moves between threads and it will not be shared between requests.  As such
 it is the perfect place to store database connection information and other
 things.  The internal stack object is called :data:`flask._app_ctx_stack`.
 Extensions are free to store additional information on the topmost level,
-assuming they pick a sufficiently unique name.
+assuming they pick a sufficiently unique name and should put there
+information there, instead on the :data:`flask.g` object which is reserved
+for user code.
 
 For more information about that, see :ref:`extension-dev`.
 
@@ -107,19 +109,19 @@ and a ``teardown_X()`` function that is registered as teardown handler.
 This is an example that connects to a database::
 
     import sqlite3
-    from flask import _app_ctx_stack
+    from flask import g
 
     def get_db():
-        top = _app_ctx_stack.top
-        if not hasattr(top, 'database'):
-            top.database = connect_to_database()
-        return top.database
+        db = getattr(g, '_database', None)
+        if db is None:
+            db = g._database = connect_to_database()
+        return db
 
     @app.teardown_appcontext
     def teardown_db(exception):
-        top = _app_ctx_stack.top
-        if hasattr(top, 'database'):
-            top.database.close()
+        db = getattr(g, '_database', None)
+        if db is not None:
+            db.close()
 
 The first time ``get_db()`` is called the connection will be established.
 To make this implicit a :class:`~werkzeug.local.LocalProxy` can be used::

docs/patterns/sqlite3.rst

@@ -10,21 +10,21 @@ easily.
 Here is a simple example of how you can use SQLite 3 with Flask::
 
     import sqlite3
-    from flask import _app_ctx_stack
+    from flask import g
 
     DATABASE = '/path/to/database.db'
 
     def get_db():
-        top = _app_ctx_stack.top
-        if not hasattr(top, 'sqlite_db'):
-            top.sqlite_db = sqlite3.connect(DATABASE)
-        return top.sqlite_db
+        db = getattr(g, '_database', None)
+        if db is None:
+            db = g._database = connect_to_database()
+        return db
 
     @app.teardown_appcontext
     def close_connection(exception):
-        top = _app_ctx_stack.top
-        if hasattr(top, 'sqlite_db'):
-            top.sqlite_db.close()
+        db = getattr(g, '_database', None)
+        if db is not None:
+            db.close()
 
 All the application needs to do in order to now use the database is having
 an active application context (which is always true if there is an request
@@ -33,6 +33,10 @@ in flight) or to create an application context itself.  At that point the
 Whenever the context is destroyed the database connection will be
 terminated.
 
+Note: if you use Flask 0.9 or older you need to use
+``flask._app_ctx_stack.top`` instead of ``g`` as the :data:`flask.g`
+object was bound to the request and not application context.
+
 Example::
 
     @app.route('/')

docs/tutorial/dbcon.rst

@@ -18,7 +18,9 @@ decorators::
 
     @app.teardown_request
     def teardown_request(exception):
-        g.db.close()
+        db = getattr(g, 'db', None)
+        if db is not None:
+            db.close()
 
 Functions marked with :meth:`~flask.Flask.before_request` are called before
 a request and passed no arguments.  Functions marked with
@@ -38,6 +40,9 @@ things on other objects because this would not work with threaded
 environments.  That special :data:`~flask.g` object does some magic behind
 the scenes to ensure it does the right thing.
 
+For an even better way to handle such resources see the :ref:`slite3`
+documentation.
+
 Continue to :ref:`tutorial-views`.
 
 .. hint:: Where do I put this code?