We must map URL patterns to our previously coded subclasses of tornado.web.RequestHandler that provide us asynchronous methods for our request handlers. The following lines create the main entry point for the application, initialize it with the URL patterns for the API, and start listening for requests. Open the previously created async_api.py file and add the following lines. The code file for the sample is included in the restful_python_chapter_10_01 folder:

application = web.Application([ 
    (r"/hexacopters/([0-9]+)", AsyncHexacopterHandler), 
    (r"/leds/([0-9]+)", AsyncLedHandler), 
    (r"/altimeters/([0-9]+)", AsyncAltimeterHandler), 
],debug=True) 
 
 
if __name__ == "__main__": 
    port = 8888 
    print("Listening at port {0}".format(port)) 
    application.listen(port) 
    ioloop.IOLoop.instance().start() 

The code creates an instance of tornado.web.Application named application with the collection of request handlers that make up the Web application. We just changed the name of the handlers with the new names that have the Async prefix.