Tornado – 'Global variables' in tornado?

Question

class MainHandler(BaseHandler):
    @tornado.web.authenticated
    def get(self):
        self.render("index.html", messages=MessageMixin.cache)

So the MainHandler does not pass request or current_user to index.html. But in index.html I tried <p>{{ current_user }}</p> <p>{{ request }}</p> and then there’s a lot of output generated. So is this some kind of ‘global variable’ in Tornado ?

Asked By: CDT

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Source

Answer 1

Several things are given to you for free in Tornado templates.

These variables do not need to be passed in – this is what you are seeing this with current_user and request.

Here is a list of all the variables you get by default

Answered By: andy boot

Answer 2

They are part of the default template context in Tornado. The documentation actually covers all of the available ones

Answered By: Andrei Taranchenko

Answer 3

The secret is in source code!
tornado.web has a function named ‘get_template_namespace’, you even can overwrite
code detail:

def get_template_namespace(self):
    """ Returns a dictionary to be used as the default template namespace.
    May be overridden by subclasses to add or modify values.
    The results of this method will be combined with additional
    defaults in the tornado.template module and keyword arguments
    to render or render_string.
    """
    namespace = dict(
        handler=self,
        request=self.request,
        current_user=self.current_user,
        locale=self.locale,
        _=self.locale.translate,
        pgettext=self.locale.pgettext,
        static_url=self.static_url,
        xsrf_form_html=self.xsrf_form_html,
        reverse_url=self.reverse_url
    )
    namespace.update(self.ui)
    return namespace

Answered By: lookinghong

Answer 4

To define custom global variables that I want to be available across the Tornado server/app I just add them to the Application itself while setting up the server:

myapp = tornado.web.Application(... all your settings ... )
myapp.myglobalvar = "somevalue"

Then across your classes you can access it by:

class MyClass(tornado.web.RequestHandler):
   def get(self):
      print("value", self.application.myglobalvar)

Answered By: Ricky Levi

Tornado – 'Global variables' in tornado?

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