How Can You Inject the Language as String Into a Jinja Template

I created a multilingual project using Flask with the help of Flask-Babel.

While the translation mechanism via GNU gettext itself is pretty straightforward, I did not know how to inject the actual language into the Jinja template, so I can use it to set <html lang="xxx">.

While it is odd that this is not mentioned in the documentation, once again StackOverflow offered solutions.

solution one

Just translate the language!

<html lang="{{ _('en') }}">

That was too simple to think of :-)

solution two

Inject it into the context.

babel = Babel(app)
...
@app.context_processor
def utility_processor():
    return dict(lang=babel.locale_selector_func())
...

<html lang="{{ lang }}">

via https://stackoverflow.com/questions/53832101/set-html-tag-lang-attribute-accordingly-using-flask-babel

solution one#

solution two#

solution one

solution two