repoze.bfg 1.3a1 has been released.  It is the first alpha of a new feature 

It may be installed via:

    easy_install -i

Or via PyPI.

The docs at are current for this version.

Below is a "what's new" document explaining the major changes from the previous 
1.2 release.  An HTML rendering of the same document is available at

A detailed changes list is available from

Special thanks to the following people who contributed code and wisdom related 
to this release:  Andrey Popp (exception view code), Hanno Schlichting (i18n 
wisdom), and Carlos de la Guardia (many, many doc fixes).

Have fun!

- C

What's New In :mod:`repoze.bfg` 1.3

This article explains the new features in :mod:`repoze.bfg` version
1.3 as compared to the previous 1.2 release.  It also documents
backwards incompatibilities between the two versions and deprecations
added to 1.3, as well as software dependency changes and notable
documentation additions.

Major Feature Additions

The major feature additions in 1.3 are:

- *Internationalization* (i18n) and *localization* (l10n) services

- *Exception views*

Internationalization and Localization

:mod:`repoze.bfg` 1.3 offers internationalization (i18n) and
localization (l10n) subsystems that can be used to translate the text
of buttons, the text of error messages and other software- and
template-defined values into the native language of a user of your

:mod:`repoze.bfg` i18n / l10n framework includes:

- Support for :term:`translation string` specifications.

- Tools allowing you to specify and work with :term:`gettext`
   :term:`message catalog` files to allow for text translation.

- :term:`Locale name` negotiation features.

- Translation and pluralization services.

For detailed documentation about :mod:`repoze.bfg`
internationalization and localization features, see

Exception Views

In :mod:`repoze.bfg` 1.3+, when you use an exception (anything that
inherits from the Python :exc:`Exception` builtin) as view context
argument, e.g.:

.. code-block:: python

       from repoze.bfg.view import bfg_view
       from repoze.bfg.exceptions import NotFound
       from webob.exc import HTTPNotFound

       def notfound_view(request):
           return HTTPNotFound()

For the above example, when the :exc:`repoze.bfg.exceptions.NotFound`
exception is raised by any view or any root factory, the
``notfound_view`` view callable will be invoked and its response

Other normal view predicates can also be used in combination with an
exception view registration:

.. code-block:: python

       from repoze.bfg.view import bfg_view
       from repoze.bfg.exceptions import NotFound
       from webob.exc import HTTPNotFound

       @bfg_view(context=NotFound, route_name='home')
       def notfound_view(request):
           return HTTPNotFound()

The above exception view names the ``route_name`` of ``home``, meaning
that it will only be called when the route matched has a name of
``home``.  You can therefore have more than one exception view for any
given exception in the system: the "most specific" one will be called
when the set of request circumstances match the view registration.
The only predicate that cannot be not be used successfully is
``name``.  The name used to look up an exception view is always the
empty string.

Existing (pre-1.3) normal views registered against objects inheriting
from :class:`Exception` will continue to work.  Exception views used
for user-defined exceptions and system exceptions used as contexts
will also work.

The feature can be used with any view registration mechanism
(`...@bfg_view`` decorator, ZCML, or imperative
:meth:`repoze.bfg.configuration.Configurator.add_view` styles).

This feature was kindly contributed by Andrey Popp.

Minor Feature Additions

- Use :term:`Venusian` to perform `...@bfg_view`` decorator scanning
   rather than relying on a BFG-internal decorator scanner.  This means
   that user-defined decorators can be defined and found during
   :mod:`repoze.bfg` scanning (although documentation for doing so is
   currently not provided).

- It is now possible to turn on Chameleon template "debugging mode"
   for all Chameleon BFG templates by setting a BFG-related Paster
   ``.ini`` file setting named ``debug_templates``. The exceptions
   raised by Chameleon templates when a rendering fails are sometimes
   less than helpful.  ``debug_templates`` allows you to configure your
   application development environment so that exceptions generated by
   Chameleon during template compilation and execution will contain
   more helpful debugging information.  This mode is on by default in
   newly generated projects.  See also :ref:`debug_templates_section`.

- A new API method named
   :meth:`repoze.bfg.configuration.Configurator.derive_view` was
   added. This API can be used to generate a BFG view callable from a
   user-supplied function, instance, or class. This useful for external
   framework and plugin authors wishing to wrap callables supplied by
   their users which follow the same calling conventions and response
   conventions as objects that can be supplied directly to BFG as a
   view callable.

Backwards Incompatibilites


Deprecations and Behavior Differences

- The exception views feature replaces the need for the
   ``set_notfound_view`` and ``set_forbidden_view`` methods of the
   :class:`repoze.bfg.configuration.Configurator` as well as the
   :ref:`notfound_directive` and :ref:`forbidden_directive` ZCML
   directives.  Those methods and directives will continue to work for
   the foreseeable future, but they are deprecated in the

Dependency Changes

- A new install-time dependency on the ``venusian`` distribution was

- A new install-time dependency on the ``translationstring``
   distribution was added (internationalization).

- Chameleon 1.2.3 or better is now required (internationalization and
   per-template debug settings).

Documentation Enhancements

- Exception view documentation was added to the :ref:`hooks_chapter`
   narrative chapter.

- A new narrative chapter entitled :ref:`i18n_chapter` was added.

- The :ref:`environment_chapter` chapter was changed: documentation
   about the ``default_locale_name`` setting was added.

- A new API chapter for the :ref:`i18n_module` module was added.

- Documentation for the new :ref:`translationdir_directive` and
   :ref:`localenegotiator_directive` ZCML directives were added.

Licensing Changes

- The Edgewall (BSD) license was added to the LICENSES.txt file, as
   some code in the :mod:`repoze.bfg.i18n` module derives from
   :term:`Babel` source.

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