如何从同步代码Python调用异步函数

Question

因此，我被锁定在一个python 3.6.2解释器中，该解释器跟随我的桌面应用程序。

我想要的是从同步方法或函数调用异步函数。

当从桌面应用程序调用python函数时，它必须是一个无法等待的普通函数。

从桌面应用程序中，我可以发送一个url列表，我想要的是从异步问题中的每个url发送回响应。

这是我的尝试，我已经标记了语法错误，我不知道如何绕过。

import fmeobjects
import asyncio
import aiohttp
import async_timeout
logger = fmeobjects.FMELogFile()
timeout = 10

class FeatureProcessor(object):
    def __init__(self):
        pass
    def input(self, feature):
        urls_and_coords = zip(feature.getAttribute('_list{}._wms'),\
        feature.getAttribute('_list{}._xmin'),\
        feature.getAttribute('_list{}._ymin'),\
        feature.getAttribute('_list{}._xmax'),\
        feature.getAttribute('_list{}._ymax'))
        -> SyntaxError: newfeature = await main(urls_and_coords)
        self.pyoutput(newfeature)

    def close(self):
       pass 

async def main(urls):
    loop = asyncio.get_event_loop()
    async with aiohttp.ClientSession(loop=loop) as session:
        feature = loop.run_until_complete(fetch_all(session, urls, loop))
        return feature

async def fetch_all(session, urls, loop):
    results = await asyncio.gather(*[loop.create_task(fetch(session, url)) for url in urls])
    return results


async def fetch(session, url):
    with async_timeout.timeout(10):
        async with session.get(url[0]) as response:
            newFeature = fmeobjects.FMEFeature()
            response_data = await response
            newFeature.setAttribute('response', response_data)
            newFeature.setAttribute('_xmin',url[1])
            newFeature.setAttribute('_xmax',url[2])
            newFeature.setAttribute('_ymin',url[3])
            newFeature.setAttribute('_ymax',url[4])
            return newFeature

我试过做这些改变： 导入fme 导入fmeobjects 导入异步 导入aiohttp 导入异步超时 logger=fmeobjects.FMELogFile（）

class FeatureProcessor(object):
    def __init__(self):
        pass
    def input(self, feature):
        urls_and_coords = zip(feature.getAttribute('_list{}._wms'),\
        feature.getAttribute('_list{}._xmin'),\
        feature.getAttribute('_list{}._ymin'),\
        feature.getAttribute('_list{}._xmax'),\
        feature.getAttribute('_list{}._ymax'))
        loop = asyncio.get_event_loop()
        result = loop.run_until_complete(main(loop, urls_and_coords))
        #feature.setAttribute('result',result)
        self.pyoutput(feature)

    def close(self):
       pass 

async def main(loop, urls):
    async with aiohttp.ClientSession(loop=loop) as session:
        return await fetch_all(session, urls, loop)


async def fetch_all(session, urls, loop):
    results = await asyncio.gather(*[loop.create_task(fetch(session, url)) for url in urls])
    return results


async def fetch(session, url):
    with async_timeout.timeout(10):
        async with session.get(url[0]) as response:
            #newFeature = fmeobjects.FMEFeature()
            response = await response
            #newFeature.setAttribute('response', response_data)
            #newFeature.setAttribute('_xmin',url[1])
            #newFeature.setAttribute('_xmax',url[2])
            #newFeature.setAttribute('_ymin',url[3])
            #newFeature.setAttribute('_ymax',url[4])
            return response, url[1], url[2], url[3], url[4]

但现在我却犯了个错误：

Python Exception <TypeError>: object ClientResponse can't be used in 'await' 
expression
Traceback (most recent call last):
  File "<string>", line 20, in input
  File "asyncio\base_events.py", line 467, in run_until_complete
  File "<string>", line 29, in main
  File "<string>", line 33, in fetch_all
  File "<string>", line 41, in fetch
TypeError: object ClientResponse can't be used in 'await' expression

Answer 1

@deceze answer可能是Python 3.6中所能做到的最好的。 但在Python 3.7中，可以通过以下方式直接使用^{}：

newfeature = asyncio.run(main(urls))

它将正确地创建、处理和关闭一个event_loop。