异步方法中的外部异步方法

Question

我的处理程序中有一部分异步代码，我需要将此部分作为外部方法并从不同的处理程序运行，但每个方法都有异步代码。你可以帮我吗？

简单的例子：

#!/usr/bin/python 

import asyncmongo 
import tornado.web  

class Handler(tornado.web.RequestHandler): 
    @tornado.web.asynchronous 
    def get(self): 
     self.db = asyncmongo.Client(pool_id='mypool', host='localhost', 
              port=27107, dbname='mydb') 

     self.db.first_names.find_one({'user_id': 1 }, 
            callback=self._on_response) 


    def _on_response(self, response, error): 
     first_name = response['first_name'] 
     data = { 
       'first_name': first_name 
     } 

     # use processor 
     first_name_html = self.generate_html("firstname.html").generate(**data) 
     last_name_html = foo() 
     self.write(first_name_html + last_name_html) 
     self.finish() 

    # this part of code is wrong! 
    # I have question about it 
    @tornado.web.asynchronous 
    def foo(self): 
     self.db.last_names.find_one({'user_id': 1 }, 
           callback=self._on_response_two) 

    def _on_response_two(self, response, error): 
     last_name = response['last_name'] 
     data = { 
       'last_name': last_name 
     } 

     # use processor 
     last_name_html = self.generate_html("lastname.html").generate(**data) 
     return last_name_html 

Answer 1

我建议

#!/usr/bin/python 

import asyncmongo 
import tornado.web  

class Handler(tornado.web.RequestHandler): 
    @tornado.web.asynchronous 
    def get(self): 
     self.db = asyncmongo.Client(pool_id='mypool', host='localhost', 
              port=27107, dbname='mydb') 

     self.db.first_names.find_one({'user_id': 1 }, 
            callback=self._on_response) 


    def _on_response(self, response, error): 
     first_name = response['first_name'] 
     data = { 
       'first_name': first_name 
     } 

     # use processor 
     self.first_name_html = self.generate_html("firstname.html").generate(**data) 
     foo() 

    def foo(self): 
     self.db.last_names.find_one({'user_id': 1 }, 
           callback=self._on_response_two) 

    def _on_response_two(self, response, error): 
     last_name = response['last_name'] 
     data = { 
       'last_name': last_name 
     } 

     # use processor 
     last_name_html = self.generate_html("lastname.html").generate(**data) 
     self.write(self.first_name_html + last_name_html) 
     self.finish() 

Answer 2

我会去的gen.engine版本，只为清晰。

#!/usr/bin/python 

import asyncmongo 
import tornado.web 
from tornado import gen 

class Handler(tornado.web.RequestHandler): 
    @tornado.web.asynchronous 
    @gen.engine 
    def get(self): 
     self.db = asyncmongo.Client(pool_id='mypool', host='localhost', 
              port=27107, dbname='mydb') 

     response, error = yield gen.Task(self.db.first_names.find_one, {'user_id': 1 }) 

     first_name = response['first_name'] 
     data = { 
       'first_name': first_name 
     } 

     # use processor 
     self.first_name_html = self.generate_html("firstname.html").generate(**data) 

     self.foo() 

    @gen.engine 
    def foo(self): 
     response, error = yield gen.Task(self.db.last_names.find_one, {'user_id': 1 }) 

     last_name = response['last_name'] 
     data = { 
       'last_name': last_name 
     } 

     # use processor 
     last_name_html = self.generate_html("lastname.html").generate(**data) 
     self.write(self.first_name_html + last_name_html) 
     self.finish()