morphi 0.3.2
i18n services for libraries and applications
License: BSD

morphi
######

Translatable text for applications and libraries.

What is morphi?
===============

``morphi`` was born out of the need to create a distributable library with internally-localized
text. Although there are several existing packages which deal with translatable text, they all
seem to focus on standalone applications; there seems to be very little available for working
with messages that are distributed along with a packaged library.


Foundations
-----------

``morphi`` is built on ideas gleaned from the following:

 * the built-in gettext module
 * Babel


Translation
===========

The ``morphi`` module provides utilities for loading ``gettext``-compatible
translators from either the local filesystem or directly from a package. The default
finder will first attempt to locate the messages files in the local filesystem (allowing
messages to be overridden on a particular system), but, if a package name is given,
will then automatically search the package for the messages files. This allows a library
to store default translation messages within the library package itself, and still have
those messages be successfully loaded at runtime.

The ``morphi`` module is primarily built around the
`Babel <http://babel.pocoo.org/en/latest/>`_ package, with
`speaklater <https://github.com/mitsuhiko/speaklater>`_ used for lazy lookups.


Message management
------------------

As the ``morphi`` module is built on ``Babel``, the standard ``distutils`` commands
provided by ``Babel`` are available, and exposed to downstream use. As such, the
standard ``extract_messages``, ``init_catalog``, ``update_catalog``, and ``compile_catalog``
commands are all present and work as described in the `Babel documentation <http://babel.pocoo.org/en/latest/setup.html>`_.

In addition to the standard ``Babel`` ``distutils`` commands, an additional ``compile_json``
command has been added. The ``compile_json`` command will compile the messages into
a JSON file compatible with the
`gettext.js <https://github.com/guillaumepotier/gettext.js>`_ javascript library.


Using translations within a library
-----------------------------------

The easiest way to use the translations is to utilize the ``Manager`` class, which
encapsulates the lookups and ``gettext`` methods, and which provides a way of loading
a new messages file after instantiation (allowing the language to be changed after
initialization).

As an example, let's say you're creating a translation-enabled library named 'mylib'.
The following might be used to initialize and load the translations for use. Details
about the "locales registry" can be found below.

.. code-block:: python
   :name: extensions.py

   # import the translation library
   from morphi.messages import Manager
   from morphi.registry import default_registry

   # instantiate the translations manager
   translation_manager = Manager(package_name='mylib')

   # register the manager with the default locales registry
   default_registry.subscribe(translation_manager)

   # initialize shorter names for the gettext functions
   gettext = translation_manager.gettext
   lazy_gettext = translation_manager.lazy_gettext
   lazy_ngettext = translation_manager.lazy_ngettext
   ngettext = translation_manager.ngettext


Note that, in general, this code should be executed only a single time for a given
package. It is recommended that this code be added to an ``extensions.py`` or similar
file, from which the gettext functions can be loaded as singletons.

.. code-block:: python

   from mylib.extensions import gettext as _

   print(_('My translatable text'))


Format variables
----------------

The gettext functions all permit additional named parameters, to be used in
formatting the translated string. The library currently supports new-style ``.format``
type formatting.

.. code-block:: python

   print(_('Hello, {name}!', name='World'))


Locales Registry
----------------

Particularly when being used with package-specific translations, the
``Manager`` will need to be able to be notified when the application's language
settings (particularly the locales) are changed, so that the correct messages
can be loaded and displayed. In order to simplify this notification,
``morphi.registry.Registry`` (with a default singleton registry
named ``default_registry``) can be used. Managers can then be subscribed or
unsubscribed to the registry, which will then notify all managers when
the locale information has changed.

.. code-block:: python

   from morphi.registry import default_registry as locales_registry

   locales_registry.locales = 'es'


Typically, a manager should be registered with the registry immediately after
it has been instantiated.


Jinja Environment
-----------------

If using Jinja templates, the Jinja environment should be initialized to add the
translation functions.

.. code-block:: python

   from morphi.helpers.jinja import configure_jinja_environment

   configure_jinja_environment(app.jinja_env, manager)

.. code-block:: jinja

   {{ _('Hello, world!') }}


JavaScript translations
-----------------------

As mentioned above, a ``compile_json`` ``distutils`` command is added by the library,
which will compile the messages to a ``messages.js``-compatible JSON file. The library
can be initialized and used as follows

.. code-block:: html
   :name: index.html

   <script src="{{url_for('mylib.static', filename='gettext.min.js')}}"></script>
   <script>
       var i18n = window.i18n({});
       window._ = function(msgid, domain) {
           return i18n.dcnpgettext.apply(
               i18n,
               [domain, undefined, msgid, undefined, undefined].concat(
                   Array.prototype.slice.call(arguments, 1)
               )
           );
       };
       {% set json_filename = find_mo_filename(package_name='mylib',
                                               extension='json',
                                               localedir='static/i18n') %}
       {% if json_filename %}
           {# strip off the leading 'static/' portion of the filename #}
           {% set json_filename = json_filename[7:] %}
       $.getJSON(
           '{{ url_for("mylib.static", filename=json_filename) }}'
       ).then(function (result) {
           i18n.loadJSON(result, 'mylib');
       });
       {% endif %}
   </script>

   . . .

   <p>_('Hello, world!', 'mylib')</p>


Note the presence of the ``find_mo_filename`` function; this function is made available
by calling the ``configure_jinja_environment`` manager method as described above.


Installation
============

``morphi`` can be installed via ``pip``:

.. code:: bash

   pip install morphi

To install for development, simply add the ``develop`` tag:

.. code:: bash

   pip install morphi[develop]


Development
===========

Testing
-------

Testing currently uses `pytest <https://docs.pytest.org/en/latest/>`_:

.. code:: bash

   pytest morphi



Changelog
=========

0.3.2 released 2025-07-10
-------------------------

- fix regression for consumers using setup.py (b7eeb2a_)

.. _b7eeb2a: https://github.com/level12/morphi/commit/b7eeb2a


0.3.1 released 2025-04-11
-------------------------

- support pyproject.toml apps (b32aa95_)

.. _b32aa95: https://github.com/level12/morphi/commit/b32aa95


0.3.0 released 2024-12-18
-------------------------

- fix deprecated pkg_resources usage (de64dba_)

.. _de64dba: https://github.com/level12/morphi/commit/de64dba


0.2.2 released 2023-03-02
-------------------------

- include pytz, since babel no longer does by default (4beab17_)

.. _4beab17: https://github.com/level12/morphi/commit/4beab17


0.2.1 released 2022-10-26
-------------------------

- update package setup and CI, resolve pkg_resources warning (cd0f750_)

.. _cd0f750: https://github.com/level12/morphi/commit/cd0f750


0.2.0 released 2020-05-12
-------------------------

- use pyp for releasing (c4cf37f_)
- support Babel 2.7+ and provide a CI helper method (bc0ef3f_)

.. _c4cf37f: https://github.com/level12/morphi/commit/c4cf37f
.. _bc0ef3f: https://github.com/level12/morphi/commit/bc0ef3f


0.1.2 released 2019-02-11
-------------------------

- Fix errors when using invalid user-supplied resource paths with the resource loader


0.1.1 released 2018-09-20
-------------------------

- Fix pkg_resources support under pyinstaller


0.1.0 released 2018-08-22
-------------------------

- Add initial translations implementation