Rosetta

Rosetta is a Django application that eases the translation process of your Django projects.

Because it doesn't export any models, Rosetta doesn't create any tables in your project's database. Rosetta can be installed and uninstalled by simply adding and removing a single entry in your project's INSTALLED_APPS and a single line in your main urls.py file.

Features

• Database independent
• Reads and writes your project's gettext catalogs (po and mo files)
• Installed and uninstalled in under a minute
• Uses Django's admin interface CSS

Requirements

Rosetta requires Django 1.4 or newer. When running with Django 1.5, Python 3.x is supported.

Installation

To install Rosetta:

1. pip install django-rosetta

2. Add 'rosetta' to the INSTALLED_APPS in your project's settings.py

3. Add an URL entry to your project's urls.py, for example:

   from django.conf import settings
   
   if 'rosetta' in settings.INSTALLED_APPS:
       urlpatterns += patterns('',
           url(r'^rosetta/', include('rosetta.urls')),
       )
   

Note: you can use whatever you wish as the URL prefix.

To uninstall Rosetta, simply comment out or remove the 'rosetta' line in your INSTALLED_APPS

Configuration

Rosetta can be configured via the following parameters, to be defined in your project settings file:

• ROSETTA_MESSAGES_PER_PAGE: Number of messages to display per page. Defaults to 10.
• ROSETTA_ENABLE_TRANSLATION_SUGGESTIONS: Enable AJAX translation suggestions. Defaults to False.
• YANDEX_TRANSLATE_KEY: Translation suggestions from Yandex Yandex.Translate API. To use this service you must first obtain an AppID key, then specify the key here. Defaults to None.
• AZURE_CLIENT_ID and AZURE_CLIENT_SECRET: Translation suggestions using the Microsoft Azure API. To use this service, you must first register for the service, then specify the 'Customer ID' and 'Primary Account Key' respectively, which you can find on your account information page on Azure Marketplace.
• ROSETTA_MESSAGES_SOURCE_LANGUAGE_CODE and ROSETTA_MESSAGES_SOURCE_LANGUAGE_NAME: Change these if the source language in your PO files isn't English. Default to 'en' and 'English' respectively.
• ROSETTA_WSGI_AUTO_RELOAD and ROSETTA_UWSGI_AUTO_RELOAD: When running WSGI daemon mode, using mod_wsgi 2.0c5 or later, this setting controls whether the contents of the gettext catalog files should be automatically reloaded by the WSGI processes each time they are modified. For performance reasons, this setting should be disabled in production environments. Default to False.
• ROSETTA_EXCLUDED_APPLICATIONS: Exclude applications defined in this list from being translated. Defaults to ().
• ROSETTA_REQUIRES_AUTH: Require authentication for all Rosetta views. Defaults to True.
• ROSETTA_POFILE_WRAP_WIDTH: Sets the line-length of the edited PO file. Set this to 0 to mimic makemessage's --no-wrap option. Defaults to 78.
• ROSETTA_STORAGE_CLASS: See the note below on Storages. Defaults to rosetta.storage.CacheRosettaStorage
• ROSETTA_ACCESS_CONTROL_FUNCTION: An alternative function that determines if a given user can access the translation views. This function receives a user as its argument, and returns a boolean specifying whether the passed user is allowed to use Rosetta or not.
• ROSETTA_LANGUAGE_GROUPS: Set to True to enable language-specific groups, which can be used to give different translators access to different languages. Instead of creating a global translators group, create individual per-language groups, e.g. translators-de, translators-fr, and assign users to these.
• ROSETTA_CACHE_NAME: When using rosetta.storage.CacheRosettaStorage, you can store the rosetta data in a specific cache. This is particularly useful when your default cache is a django.core.cache.backends.dummy.DummyCache (which happens on pre-production environments). If unset, it will default to rosetta if a cache with this name exists, or default if not.
• ROSETTA_POFILENAMES: Defines which po filenames are exposed in the web interface. Defaults to ('django.po', 'djangojs.po')
• ROSETTA_EXCLUDE_PATHS: Exclude paths defined in this list from being searched (usually ends with "locale"). Defaults to ()

Storages

To prevent re-reading and parsing the PO file catalogs over and over again, Rosetta stores them in a volatile location. This can be either the HTTP session or the Django cache.

Django 1.4 has introduced a signed cookie session backend, which stores the whole content of the session in an encrypted cookie. Unfortunately this doesn't work with large PO files, as the limit of 4096 chars that can be stored in a cookie are easily exceeded.

In this case the Cache-based backend should be used (by setting ROSETTA_STORAGE_CLASS = 'rosetta.storage.CacheRosettaStorage'). Please make sure that a proper CACHES backend is configured in your Django settings if your Django app is being served in a multi-process environment, or the different server processes, serving subsequent requests, won't find the storage data left by previous requests.

Alternatively you can switch back to using the Session based storage by setting ROSETTA_STORAGE_CLASS = 'rosetta.storage.SessionRosettaStorage in your settings. This is perfectly safe on Django 1.3. On Django 1.4 or higher make sure you have DON'T use the signed_cookies SESSION_BACKEND with this Rosetta storage backend or funky things might happen.

TL;DR: if you run Django with gunincorn, mod-wsgi or other multi-process environment, the Django-default CACHES LocMemCache backend won't suffice: use memcache instead, or you will run into issues.

Security

Because Rosetta requires write access to some of the files in your Django project, access to the application is restricted to the administrator user only (as defined in your project's Admin interface)

If you wish to grant editing access to other users:

1. Create a 'translators' group in your admin interface
2. Add the user you wish to grant translating rights to this group

Usage

Generate a batch of files to translate

See Django's documentation on Internationalization to setup your project to use i18n and create the gettext catalog files.

Translate away!

Start your Django development server and point your browser to the URL prefix you have chosen during the installation process. You will get to the file selection window.

Select a file and translate each untranslated message. Whenever a new batch of messages is processed, Rosetta updates the corresponding django.po file and regenerates the corresponding mo file.

This means your project's labels will be translated right away, unfortunately you'll still have to restart the webserver for the changes to take effect. (NEW: if your webserver supports it, you can force auto-reloading of the translated catalog whenever a change was saved. See the note regarding the ROSETTA_WSGI_AUTO_RELOAD variable in conf/settings.py.

If the webserver doesn't have write access on the catalog files (as shown in the screen shot below) an archive of the catalog files can be downloaded.

Translating Rosetta itself

By default Rosetta hides its own catalog files in the file selection interface (shown above.) If you would like to translate Rosetta to your own language:

1. Create a subdirectory for your locale inside Rosetta's locale directory, e.g. rosetta/locale/XX/LC_MESSAGES
2. Instruct Django to create the initial catalog, by running django-admin.py makemessages -l XX inside Rosetta's directory (refer to Django's documentation on i18n for details)
3. Instruct Rosetta to look for its own catalogs, by appending ?rosetta to the language selection page's URL, e.g. http://127.0.0.1:8000/rosetta/pick/?rosetta
4. Translate as usual
5. Send a pull request if you feel like sharing

Acknowledgments

• Rosetta uses the excellent polib library to parse and handle gettext files.