webapp2 jinja2 context_processor

Question

I am building a project on GAE, webapp2, jinja2 and I use engineauth for authorization. I need something like Django's context_processor in order to use session, user and some other variables from webapp2.request in templates. Please, help me to solve this problem.

Answer 1

There are many ways to achieve this.

The simplest way probably looks like this:

def extra_context(handler, context=None):
    """
    Adds extra context.
    """

    context = context or {}

    # You can load and run various template processors from settings like Django does.
    # I don't do this in my projects because I'm not building yet another framework
    # so I like to keep it simple:

    return dict({'request': handler.request}, **context)


# --- somewhere in response handler ---
def get(self):
    my_context = {}
    template = get_template_somehow()
    self.response.out.write(template.render(**extra_context(self, my_context))

I like when my variables are in template globals, then I can access them in my template widgets without having to pass around bunch of vars in template. So I am doing it like this:

def get_template_globals(handler):
    return {
        'request': handler.request,
        'settings': <...>
    }


class MyHandlerBase(webapp.RequestHandler):
    def render(self, context=None):
        context = context or {}
        globals_ = get_template_globals(self)
        template = jinja_env.get_template(template_name, globals=globals_)
        self.response.out.write(template.render(**context))

There are other methods in: Context processor using Werkzeug and Jinja2