django translate variable content in template

I'm using {% trans %} template tag. Django docs say:

The {% trans %} template tag translates either a constant string (enclosed in single or double quotes) or variable content:

{% trans "This is the title." %} {% trans myvar %}

https://docs.djangoproject.com/en/4.0/topics/i18n/translation/#translate-template-tag

I found it 开发者_运维百科impossible to do {% trans myvar %} because myvar simply doesn't show up in django.po file after running makemessages command.

Am I using it wrong? Could some help me with this?

---

You can use the blocktrans template tag in this case:

{% blocktrans %} This is the title: {{ myvar }} {% endblocktrans %}

---

{% trans myvar %} just works. So check your PO file to make sure that the value of myvar is in PO msgid.

<title>{% trans myvar %}</title>

For example if myvar contains "Some Publisher" you can write the following in the PO file:

msgid "Some Publisher"
msgstr "কিছু প্রকাশক"

Also make sure you have ran:

python manage.py compilemessages

---

Django can't guess what is in that variable, so you have to translate it yourself by adding both the english (msgid) and the localized (msgstr) strings.

---

My experience here is that variable translation does not work in templates on its own. However I came to a suitable solution when the content of the variables is known (I mean that they are not free text, but a set of choices you set in the database).

You need to force the translation in the view or in a filter tag.

To sum up:

1. Use blocktrans in your templates
2. Force variables to be translated
   • You either set variables in context that are already marked for transtalion
   • or use a filter to translate them
3. Generate translations in .po file

The story is like this:

views.py

def my_view(request):
    return render(request, 'i18n_test.html', {'salutation':"Hola"})

templates/i18n_test.html

...
{% blocktrans %}{{ salutation }}{% endblocktrans %}
...

And when I render the template it always shows Hola whichever the current language is.

To force the translation, in the view we need to use ugettext.

def my_view(request):
    return render(request, 'i18n_test.html', {'salutation':ugettext("Hola")})

However it is not always possible to access the view. So I prefer to use a filter like this.

templatetags/i18n_extras.py

@register.filter(name='translate')
def translate(text):
  try:    
    return ugettext(text)

And the template becomes

...
{% blocktrans s=salutation|translate %}{{ s }}{% endblocktrans %}
...

And produces Hola, Hello, Ciao, Salut depending on the current language.

The disadvantage (as pointed out in the docs ) is that makemessages does not automatically include these translations, so we need to include them manually. In django.po file:

locales/en/django.po

...
msgid "Hola"
msgstr "Hello"
...

---

You can translate the variable in the python code like here for settings.SITE_NAME:

from django.conf import settings
from django.utils.translation import ugettext_lazy as _

def processor004(request):
 my_dict = {
    'site_id004': settings.SITE_ID,
    'site_name004': _(settings.SITE_NAME),
    'installed_apps004': settings.INSTALLED_APPS,
    'embedded_widget004': settings.EMBEDDED_WIDGET,
    'base_template004': settings.BASE_TEMPLATE,
}

return my_dict

---

make own tags

from django.utils.translation import ugettext as _

@register.simple_tag
def trans2(tr, *args, **kwargs):
    # print(':', kwargs)
    trans = _(tr)
    trans_str = trans.format(**kwargs)
    return trans_str

in template:

{% trans2 columns_once.res_data.message with value=columns_once.res_data.recommend%}

in django.po

#: default_content.py:136
msgid "_audit_recommend_speed"
msgstr "Рекомендованная скорость до {value} сек"

---

It's a complex elegant solution that may help if you are translating values from model fields: http://django-modeltranslation.readthedocs.org

"Modeltranslation

The modeltranslation application is used to translate dynamic content of existing Django models to an arbitrary number of languages without having to change the original model classes."

---

To me, this happened when I had the TEMPLATES.DIRS outside my Django project directory. Fetching the templates into the project directory solved the problem.

---

As one workaround, you can collect {% trans %}(django 3.0 and below) or {% translate %}(django 3.1 and above) tags between {% comment %} and {% endcomment %} in one template. This will save your efforts to repeat typing the same msgid should you have more than one language po file.

{% comment %}
{% trans "Tea" %}
{% trans "Clothes" %}
{% endcomment %.}

Make sure you run django-admin makemessages --all after putting the aforementioned code.