Handling Internationalization And Localization
==============================================

:Status: Work in progress

.. contents:: Table of Contents
    :depth: 2

Turbogears2 relies on Pylons and Babel for i18n and l10n support. So
if this document is not enough you will want to check their respective
documentation:

 * Pylons' `Internationalization and Localization`_ doc (which also
   contains "Using Babel" section)
 * Babel's UserGuide_

A quickstarted project comes fully i18n enabled so you should get
started quickly.

If you're lucky enough you'll even see "Your application is now
running" message in your language.

Language Auto-Select
--------------------

Turbogears2 contains the logic (hardwired in the TurboGearsController
class at the moment) to setup request's language based on browser's
preferences(*).

[*] - Every modern browser sends a special header along with every web
request which tells the server which language it would prefer to see
in a response.


An i18n Quick Start
-------------------

After quickstarting your project, you will notice that the setup.py
file contains the following section::

    message_extractors = {'yourapp': [
             ('**.py', 'python', None),
             ('templates/**.mako', 'mako', None),
             ('templates/**.html', 'genshi', None),
             ('public/**', 'ignore', None)]},

This is an extraction method mapping that indicates to distutils which
files should be searched for strings to be translated.  TurboGears2
uses Babel to extract messages to a .pot file in your project's i18n
directory.  Don't forget to add it to your revision control system if
you use one.

1. Extract all the translatable strings from your project's files by
using the following command::

    python setup.py extract_messages

This command will generate a "pot" file in the i18n folder of your
application.  This pot file is the reference file that serves for all
the different translations.


2. Create a translation catalog for your language, let's take 'zh_tw'
for example::

    python setup.py init_catalog -l zh_tw

3. Edit your language in i18n/[country
code]/LC_MESSAGES/[project-name].po

If you're not an expert in i18n or if you would like to give the files
to someone else so that he helps you we recommend that you use the
really nice poedit program. This program works nicely on GNU/Linux and
Windows and provides a nice user-interface to edit po files.

.. image:: ../_static/poedit.png

4. Compile your lang::

    python setup.py compile_catalog  

5. Config development.ini::

    [app:main]
    use = egg: my-project
    full_stack = true
    lang = zh_tw

6. Start server::

    paster serve --reload development.ini

And see the local message show on the screen.


Commands
--------


To fresh start a translation, you could use the following command to
handle your locales:

init_catalog
~~~~~~~~~~~~

You can extract all messages from the project with the following
command::

  python setup.py init_catalog -l [country code]

The country code could be es(Spanish), fr(France), zh_tw(Taiwan),
jp(JAPAN), ru(Russian), or any other country code.

Compile Catalog
~~~~~~~~~~~~~~~

You can extract all messages from the project with the following command::

  python setup.py compile_catalog

Update Catalog
~~~~~~~~~~~~~~

You can update the catalog with the following command::

  python setup.py update_catalog


.. _`Internationalization and Localization`: http://wiki.pylonshq.com/display/pylonsdocs/Internationalization+and+Localization
.. _UserGuide: http://babel.edgewall.org/wiki/Documentation/index.html
