how to correctly work out of context

[wiwengweng]

Hi, all. I have two subprocesses. one for flask web(called web.py), and one for some background tasks(called task.py).
flask-babel works inside the web context, but also the task subprocess will need some translations.
so, I import web app into the task.py and use the app.test_request_context in order to make translations work for me.
it works at first but then I found task.py will also get the default language only.
here is the web.py:

app.config['BABEL_DEFAULT_LOCALE'] = 'en'
babel = Babel(app)

@babel.localeselector
def get_locale():
    return request.accept_languages.best_match(['zh', 'en'])

task.py

from web import app
def task():
    try:
        with app.test_request_context() as ctx:
            sio.emit('loading', {'data': _("please wait a moment.")})
....

so how can I get the correct locale before I return the translation?? TIA :)

[wiwengweng]

I also see this function:

flask_babel\__init__.py

def get_translations():
    """Returns the correct gettext translations that should be used for
    this request.  This will never fail and return a dummy translation
    object if used outside of the request or if a translation cannot be
    found.
    """
    ctx = _get_current_context()

    if ctx is None:
        return support.NullTranslations()

    translations = getattr(ctx, 'babel_translations', None)
    if translations is None:
......

I track codes to this function and find the ctx has the attribute 'babel_translations', and this translation catalog seems to be related with the default locale. Is it a bug, or I can get the locale from 'babel_localeselector'??

[tvuotila]

@babel.localeselector
def get_locale():
    return request.accept_languages.best_match(['zh', 'en'])

is what decided which locale to use. If it returns None, the default locale is used.

For example, if you would want to use locale zh, you could write

@babel.localeselector
def get_locale():
    return 'zh'

Probably you want to use something smarter there.

I think you should take a look at force_locale if that solves your problem.

[wiwengweng]

thanks, @tvuotila I did not use force_locale and just solve this as you advised.

[4lph4-Ph4un]

Hi, I'm still unable to use this even with force_locale. Since I have to use multiple locales on my app, I cannot just force a return value on get_locale either. Is there something wrong with my use case. I use Zappa's @task to run different asynchronous tasks on AWS. Here's the minimum setup where I cannot get a translation forced. The real use case likely reads the language from user object's settings:

@task
def async_translation_test():
    from instababy import app
    with force_locale("fi"):
        output = _("Test notification 4 %(name)s", name="Test")
        app.logger.debug(output)

I have working translations on HTML -templates and routines that use requests, but somehow this doesn't seem to work. The logger just messages the default English translation and not Finnish one.

[tvuotila]

I have working translations on HTML -templates and routines that use requests, but somehow this doesn't seem to work.

You need the request for this to work.

@task
def async_translation_test():
    from instababy import app
    with app.test_request_context():
        with force_locale("fi"):
            output = _("Test notification 4 %(name)s", name="Test")
            app.logger.debug(output)

[4lph4-Ph4un]

Ah thanks for the reply. I assumed test_request_context() was only used for testing, but seems it is used in variety of situations. :)

[4lph4-Ph4un]

Uff.. somehow doesn't seem to work :/ I'll try to get more info to the get bottom of this.