from flask import Flask, [...]\nfrom flask.ext.babel import Babel, gettext\napp = Flask(__name__)\nbabel = Babel(app)<\/pre>\nIn your configuration, add a dictionary named LANGUAGES. In this example, we add two locales, english (\u2018en\u2019) and german (\u2018de\u2019).<\/p>\n
# add to your app.config or config.py file\nLANGUAGES = {\n 'en': 'English',\n 'de': 'Deutsch'\n}<\/pre>\nWe will use this dictionary for a little helper function that Babel offers:<\/p>\n
# add to you main app code\n@babel.localeselector\ndef get_locale():\n return request.accept_languages.best_match(app.config['LANGUAGES'].keys())<\/pre>\nThis convenient tool will automatically choose the best matching locale, based on the Accept-Language header from the incoming request.
\nHint: for testing purposes, you can directly return a language code, for example: return \u2018de\u2019<\/em>
\nOne more thing! Create a config file for Babel. We will chew through the details later on, but for now, simply create a file named babel.cfg<\/strong> in the top-level directory of you app:<\/p>\n[python: **.py]\n[jinja2: **\/templates\/**.html]\nextensions=jinja2.ext.autoescape,jinja2.ext.with_<\/pre>\n<\/span>Tagging Strings<\/span><\/h3>\nNow it\u2019s time to tag all the Strings you want to translate. In a typical Flask app, there will be two types of Strings that require translating. One being hard-coded Strings in your .py files, the other being Strings in your .html Jinja2 templates.
\nTag them by adding a gettext(\u2018String\u2019) call to them, like so:<\/p>\n
slogan = 'This app is awesome.'\nflash('Login failed')<\/pre>\nbecomes<\/p>\n
slogan = gettext('This app is awesome.')\nflash(gettext('Login failed'))<\/pre>\nFor your Jinja2 templates, this is also very straightforward, for example:<\/p>\n
<b>Free Trial<\/b>\n<input type=\"submit\" value=\"Sign up\"\/><\/pre>\nbecomes<\/p>\n
<b>{{ gettext('Free Trial') }}<\/b>\n<input type=\"submit\" value=\"{{ gettext('Sign up') }}\"\/><\/pre>\nHint: you can use _() as a shortcut for gettext().<\/em>
\nNote that the english string is also the key (msgid) that gettext will use for when looking up the corosponding Translation value (msgstr).<\/p>\n<\/span>Building Locales<\/span><\/h3>\nWhen all strings are tagged, it is time to build a catalog for the Locales we want to create. Run:<\/p>\n
pybabel extract -F babel.cfg -o messages.pot<\/code><\/pre>\nThis checks all files specified in babel.cfg and searches thru them to find tagged strings and outputs them to messages.pot.
\nNext, run:<\/p>\n
pybabel init -i messages.pot -d translations -l de<\/code><\/pre>\nThis will use the index from messages.pot to build a german (\u2018de\u2019) locale in our translations directory. Don\u2019t worry, if the directory doesn\u2019t exist yet, pybabel will create it for you.
\nFinally it is time to translate the Strings.
\nWith your favorite text editor, open \u2018translations\/de\/LC_MESSAGES\/messages.po\u2019. You can now start translating the msgstr<\/strong> values. When you are done editing, there is only one step left, compile all .po files in your translation directory:<\/p>\npybabel compile -d translations<\/code><\/pre>\nDone! Start playing around with your app. Remember, the locale is chosen based on the Accept-Language Header that is being sent by your Browser.
\nCheck out our full Flask-Babel example app<\/a>, a modified version of Flaskr, the official Flask demo app.<\/p>\n