龙卷风中的自定义模板管道功能

Question

How do you define a custom template pipe function that is available on all template in Tornado.

Trying to achieve something like this:

{{ name | transform_me }}

Answer 1

You can pass custom ui_methods with Application, that will be available in all templates:

import tornado.ioloop
import tornado.web


class MyHandler(tornado.web.RequestHandler):
    def get(self):
        self.render("mytemplate.html")


def my_custom_function(handler, *args):
    # handler is the RequestHandler of current handled request  
    # args are the agrs passed through template
    return 'my_custom {}'.format(str(args)) 

if __name__ == "__main__":
    application = tornado.web.Application(
        [(r"/", MyHandler),],
        # expose function to the templates
        ui_methods={'my_custom_function': my_custom_function}
    )
    application.listen(8888)
    tornado.ioloop.IOLoop.instance().start()

and template file

{{ my_custom_function('adsadasda', 'qweqweq') }}

Answer 2

You can have your controllers share a Base RequestHandler whose get_template_namespace method is overwritten.

You probably want to have a filters module.

filters.py

def transform_me(value):
    # transform value
    return transformed_value


filters = {
   'transform_me': transform_me
}

Shared base class

You can add your filters to the template namespace. When render is called from handlers that inherit from BaseRequestHandler , your filters will be available.

from filters import filters

class BaseRequestHandler(RequestHandler):
   def get_template_namespace(self):
       namespace = super(BaseRequestHandler, self).get_template_namespace()
       namespace.update(filters)
       return namespace

Reference:

• https://github.com/tornadoweb/tornado/blob/master/tornado/web.py#L887