How to use the built-in translations provided by WTForms

[greyli]

As describe in WTForms's documentation here, we can define a base class to set the default locale app-widely:

from wtforms import Form

class MyBaseForm(Form):
    class Meta:
        locales = ['es_ES', 'es']

How to achieve this with Flask-WTF?

[greyli]

Actually, I don't know too much about i18n.

Install Flask-Babel and set BABEL_DEFAULT_LOCALE will do the same thing. However, I want to know is it possible to make it work without Flask-Babel (Babel)?

[lepture]

@greyli No. You must use Flask-Babel to enable i18n.

[greyli]

Thanks!

[greyli]

@lepture Sorry to disturb you, I thought maybe there is a misunderstanding. Actually, I just want to set the default error message's language to Chinese. How to do it without Flask-Babel or Babel just like use pure WTForms?

Similar to this SO question.

[greyli]

The working code with pure WTForms:

class MyBaseForm(Form):
    class Meta:
        locales = ['zh']

class HelloForm(MyBaseForm):
    name = StringField('Name', validators=[DataRequired()])
    submit = SubmitField()

Then the error message will be displayed in Chinese.

[lepture]

@greyli The current implementation is using Babel to determine the language automatically. In this case, you will have to use Babel.

[greyli]

Is it possible to add support for this usage?

I thought it's a common need. Sometimes people don't want to add i18n/l10n support, the only thing they want is using the specific built-in translation.

[greyli]

Just something like #300, but with a better implementation.

[greyli]

If you think it's ok, I'll submit a PR.

[lepture]

Sure, if it won’t take too much work.