Languages and internationalization

weppy provides an integrated powerful multi-language system, based on the web2py's one, which helps you to write application supporting different languages.
But how does it work?

from weppy import App, T
app = App(__name__)

def index():
    hello = T('Hello, my dear!')
    return dict(hello=hello)

As you can see, weppy provide a language translator with the T object: this is available also into the templating environment, and it tells weppy to translate the string depending on clients locale.

So what you should do with languages? You can just write in languages/ file of your application:

"Hello, my dear!": "Ciao, mio caro!"

and the hello message will be translated when the user request the italian language.

– awesome. But how weppy decides which language should load for a specific client?
actually, you can choose that

weppy has two different ways to handle languages in your application: using clients' HTTP headers or using urls. Let's see the differences between the two systems.

Translation using HTTP headers

Let's say your application has english as default language and you want your application to be available also in italian language, as the above example.
On default settings, the user's requested language is determined by the "Accept-Language" field in the HTTP header, which means that if user1 has its browser accepting italian language, visiting '' he will see the italian version, while user2 that has its browser accepting any other language different from italian will see the english one.

As you imagined, using this translation technique is quite easy, as the available languages are automatically defined based on the translation files you have inside languages folder of your application. For example


will make your application available in english and italian, while


will make your application available in english, italian and spanish.

You can obviously change the default language of your application, just writing:

app.language_default = 'it'

Translation using routing

There are many scenarios where you want your application to use different urls to separate contents depending on the language.

Let's say again you have your application with english as the default language and you provide also an italian version; to achieve the routing translation behavior under weppy you should write:

app.languages = ['en', 'it']
app.language_default = 'en'
app.language_force_on_url = True

and weppy will automatically add the support for language on your routing rules to the follow:

requested url behaviour
/anexampleurl shows up the contents with the default language
/it/anexampleurl shows up the contents with the italian language

As you can see, the routing way needs you to explicitly tells to weppy which languages should be available into your application so it can build the routing tables.