如何使用回調將同步函數轉換爲python中的異步函數？

Question

我正在使用龍捲風框架和我的所有功能已被寫入同步。我將如何使這些異步？

class AuthLoginHandler(BaseHandler): 
    @tornado.web.asynchronous 
    def get(self): 

     self.render("login.html") 

    def post(self): 
     username = self.get_argument("UserName",strip = True) 
     password = self.get_argument("Password",strip = True) 
     user = auth_actions.login(username,password) 
     if not user: 
      self.redirect("/auth/login") 
      return 

     #user = user_actions.get_my_data(self.db,user['_id']) 

     self.set_secure_cookie("userdata", tornado.escape.json_encode(dumps(user.to_mongo()))) 
     self.redirect("/") 


def login(username,password,callback=None): 
    m = hashlib.md5() 
    m.update(password) 
    hashed = m.hexdigest() 
    login = User.objects(UserName=username.lower(),Password=hashed).exclude("Password","Wall","FriendsRequested","Friends","FriendsRequesting") 
    if login.first() is None: 
     login = User.objects(Email=username.lower(),Password=hashed).exclude("Password","Wall","FriendsRequested","Friends","FriendsRequesting") 
     if login.first() is None: 
      return None 
    logger.info(username + " has logged in") 
    if callback != None: 
     return callback(login.first()) 

    return login.first() 

Answer 1

正如安迪提到的那樣，你將需要一個單獨的線程。以下代碼使用tornado-gen的generator - coroutine方法。 另請注意run_asyncdecorator將自己的函數包裝在自己的線程中。

import tornado.ioloop 
import tornado.web 
import tornado.gen 
import time 
from threading import Thread 
from functools import wraps 

def run_async(func): 
    @wraps(func) 
    def async_func(*args, **kwargs): 
    func_hl = Thread(target = func, args = args, kwargs = kwargs) 
    func_hl.start() 
    return func_hl 

    return async_func 

@run_async 
def login(username,password,callback=None): 
    m = hashlib.md5() 
    m.update(password) 
    hashed = m.hexdigest() 
    login = User.objects(UserName=username.lower(),Password=hashed).exclude("Password","Wall","FriendsRequested","Friends","FriendsRequesting") 
    if login.first() is None: 
    login = User.objects(Email=username.lower(),Password=hashed).exclude("Password","Wall","FriendsRequested","Friends","FriendsRequesting") 
    if login.first() is None: 
     return None 
    logger.info(username + " has logged in") 
    if callback != None: 
    return callback(login.first()) 
    return login.first() 


class AuthLoginHandler(BaseHandler): 
    @tornado.web.asynchronous 
    def get(self): 
    self.render("login.html") 

    @tornado.web.asynchronous 
    @tornado.gen.coroutine 
    def post(self): 
    username = self.get_argument("UserName",strip = True) 
    password = self.get_argument("Password",strip = True) 
    user = yield tornado.gen.Task(auth_actions.login, username, password) 
    if not user: 
     self.redirect("/auth/login") 
     return 
    self.set_secure_cookie("userdata", tornado.escape.json_encode(dumps(user.to_mongo()))) 
    self.redirect("/") 

Answer 2

如果你打算散列密碼，你最好在單獨的線程中完成它。這是因爲散列需要很長時間才能執行，並會阻塞主線程。

Here is an example of hashing on a separate thread

需要注意的是龍捲風的維護者本達內爾建議使用一個單獨的線程來完成密碼哈希值：see this google group。