Flask-Babel how to use translation in Jinja template file

Question

In my Flask application, in main.py file, I defined:

from flaskext.babel import gettext
....
def somefun():
    return render_template('some.html', messages=messages)

in template file some.html, I used:

<input type='text' name='keywords' value='{{ keywords|default('') }}' placeholder='{{ gettext('Search...') }}' />

This gives an error:

<input type='text' name='keywords' value='{{ keywords|default('') }}' placeholder='{{ gettext('Search...') }}' />
UndefinedError: 'gettext' is undefined

How to import this function for template use?

score 28 · Accepted Answer · edited Nov 05 '17 at 09:33

28

Unfortunately this is not documented at all, but Flask-Babel is transparently using Jinja2's i18n extension. This means that by default, following functions for expressions are available: gettext, ngettext and _.

There's also possibility to use template tags:

{% trans %}foo{% endtrans%}

{% trans num %}
There is {{ num }} object.
{% pluralize %}
There are {{ num }} objects.
{% endtrans %}

And the bug report about missing docs that's waiting for patches ;)

edited Nov 05 '17 at 09:33

manash

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answered Mar 01 '12 at 12:10

plaes

31,788
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2

it's not true, I can't use "_" without any importing actions. – Brent Jiang Mar 01 '12 at 13:08
@BrentJiang Did you actually init the Flask-Babel extension? – plaes Mar 01 '12 at 13:17
3

thanks, it works after create 'from flaskext.babel import Babel' and 'babel = Babel(app)' – Brent Jiang Mar 01 '12 at 13:28
you are a life saver – Jacquot Jan 08 '18 at 23:14
1

I needed `{% trans with name=varFromContext %}Hello {{ name }}{% endtrans %}` – Chris May 25 '18 at 16:08
https://support.sendwithus.com/templating/translating_templates/ – Natim Apr 01 '20 at 14:08

Flask-Babel how to use translation in Jinja template file

1 Answers1