Cheatsheet

Basic App

from quart import Quart, render_template
from quart_babel import Babel, format_gettext

app = Quart(__name__)

babel = Babel(app)

@app.route("/index")
async def index():
    hello = format_gettext('Hello')

    return await render_template('index.html', hello=hello)

Large Applications

yourapplication/routes.py

from quart import Blueprint
from quart_babel import format_gettext

bp = Blueprint('main', __name__, url_prefix='/photos')

@app.route("/index")
async def index():
    hello = format_gettext('Hello')

    return await render_template('index.html', hello=hello)

# Routes & additional code here.

youapplication/app.py

from quart import Quart
from quart_babel import Babel

babel = Babel()

def create_app() -> Quart:
    app = Quart(__name__)

    babel.init_app(app)

    from .routes import bp as main_bp
    app.register_blueprint(main_bp)

    # Other app registration here.

    return app

Configuration Variables

app.py

from quart import Quart
from quart_babel import Babel

BABEL_DEFAULT_LOCALE = 'de_DE'
BABEL_DEFAULT_TIMEZONE = 'Europe/Berlin'
BABEL_CONFIGURE_JINJA = True # Showing default as example
BABEL_DOMAIN = 'myapp'

app = Quart(__name__)
app.config.from_pyfile(__name__)

Babel(app)

# Setup the rest of the app

Locale & Timezone Selector Functions

Async Code

import asyncio
from quart import g, request
from quart_babel import Babel, select_locale_by_request, select_timezone_by_request
from quart_babel.typing import ASGIRequest, IPApiKey

app = Quart(__name__)

async def locale_selector(request: ASGIRequest):
   # We will use async sleep to give an example that this can
   # be async. Don't do this in production.
   await asyncio.sleep(0.1)
   # if a user is logged in, use the locale from the user settings
   user = getattr(g, 'user', None)
   if user is not None:
       return user.locale
   # otherwise use the select locale by request function.
   return select_locale_by_request(request)

async def timezone_selector(request: ASGIRequest):
    # We will use async sleep to give an example that this can
    # be async. Don't do this in production.
    await asyncio.sleep(0.2)
    user = getattr(g, 'user', None)
    if user is not None:
        return user.timezone
    # otherwise use default timezone by returning None.
    return None

babel = Babel(app, locale_selector=get_locale, timezone_selector=timezone_selector)

Formatting Dates & Times

The below code assumes that you are within the app context.

orig_date = datetime(1987, 3, 5, 17, 12)

date = format_date(orig_date)
date_time = format_datetime(orig_date)
time = ormat_time(orig_date)

delta = timedelta(6)
time_d = format_timedelta(delta, threshold=1)

Formatting Numbers

The below code assumes that you are within the app context.

# Regular number
number = 1099
t_num = format_number(number)

# Decimal number
dec_number = 1010.99
d_num = format_decimal(Decimal(dec_number))

# Percentage number
per_number = 0.19
p_num = format_percent(per_number)

# Scientific number
sci_number = 10000
s_num = format_scientific(sci_number)

Using Translations

from datetime import datetime
from quart import quart
from quart_babel import Babel, gettext, ngettext

app = Quart(__name__)
Babel(app)

@app.route('/')
async def index():
    # Simple string
    simple_string = gettext(u'A simple string')

    # String with value
    value_string = gettext(u'Value: %(value)s', value=42)

    # Plural string
    p_string = ngettext(u'%(num)s Apple', u'%(num)s Apples', number_of_apples)

    # .... Additional route code here, such as return.

Lazy Strings

from quart_babel import lazy_gettext

class MyForm(formlibrary.FormBase):
    success_message = lazy_gettext(u'The form was successfully saved.')

Translation Domains

Application Custom Domain

from quart import Quart
from quart_babel import Babel, Domain

app = Quart(__name__)
domain = Domain(domain='myext')
babel = Babel(app, default_domain=domain)

Extension Custom Domain

from quart_babel import Domain

mydomain = Domain(domain='myext')

mydomain.lazy_gettext('Hello World!')