django translate variable content in template

Question

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 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?

Answer 1

You can use the blocktrans template tag in this case:

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

Answer 2

{% 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 

Answer 3

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"
...

Answer 4

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.