diff options
Diffstat (limited to 'docs/narr')
| -rw-r--r-- | docs/narr/urldispatch.rst | 25 |
1 files changed, 14 insertions, 11 deletions
diff --git a/docs/narr/urldispatch.rst b/docs/narr/urldispatch.rst index 9e478ef2d..3550d57f6 100644 --- a/docs/narr/urldispatch.rst +++ b/docs/narr/urldispatch.rst @@ -950,7 +950,7 @@ general description of how to configure a not found view. Cleaning Up After a Request --------------------------- -Often it's required that some cleanup be performed at the end of a +Sometimes it's required that some cleanup be performed at the end of a request when a database connection is involved. When :term:`traversal` is used, this cleanup is often done as a side effect of the traversal :term:`root factory`. Often the root factory will @@ -961,11 +961,12 @@ is not open to you. Instead of putting this cleanup logic in the root factory, however, you can cause a subscriber to be fired when a new request is detected; -the subscriber can do this work. For example, let's say you have a -``mypackage`` :mod:`repoze.bfg` application package that uses -SQLAlchemy, and you'd like the current SQLAlchemy database session to -be removed after each request. Put the following in the -``mypackage.run`` module: +the subscriber can do this work. + +For example, let's say you have a ``mypackage`` :mod:`repoze.bfg` +application package that uses SQLAlchemy, and you'd like the current +SQLAlchemy database session to be removed after each request. Put the +following in the ``mypackage.run`` module: .. ignore-next-block .. code-block:: python @@ -993,11 +994,13 @@ Then in the ``configure.zcml`` of your package, inject the following: This will cause the DBSession to be removed whenever the WSGI environment is destroyed (usually at the end of every request). -Alternate mechanisms for performing this sort of cleanup exist; an -alternate mechanism which uses cleanup services offered by the -``repoze.tm2`` package is used in the SQLAlchemy-related ``paster`` -templates generated by :mod:`repoze.bfg` and within -:ref:`sql_tm2_cleanup` within the :ref:`bfg_sql_wiki_tutorial`. +.. note:: This is only an example. In particular, it is not necessary + to cause ``DBSession.remove`` to be called as the result of an + event listener in an application generated from any + :mod:`repoze.bfg` paster template, because these all use the + ``repoze.tm2`` middleware. The cleanup done by + ``DBSession.remove`` is unnecessary when ``repoze.tm2`` middleware + is in the WSGI pipeline. .. index:: pair: URL dispatch; security |