等待多个 aiohttp 请求导致 'Session is closed' 错误

Question

我正在编写一个帮助程序 class 以异步方式处理多个 url 请求。代码如下。

class urlAsyncClient(object):
    def  __init__(self, url_arr):
        self.url_arr = url_arr

    async def async_worker(self):
        result = await self.__run()
        return result

    async def __run(self):
        pending_req = []
        async with aiohttp.ClientSession() as session:
            for url in self.url_arr:
                r = self.__fetch(session, url)
                pending_req.append(r)
        #Awaiting the results altogether instead of one by one
        result = await asyncio.wait(pending_req)
        return result

    @staticmethod
    async def __fetch(session, url):
        async with session.get(url) as response: #ERROR here
            status_code = response.status
            if status_code == 200:
                return await response.json()
            else:
                result = await response.text()
                print('Error ' + str(response.status_code) + ': ' + result)
                return {"error": result}

因为一个一个的等待结果在异步中显得毫无意义。我把他们放到一个数组里一起等await asyncio.wait(pending_req).

但似乎这不是正确的方法，因为我收到以下错误

in __fetch async with session.get(url) as response: RuntimeError: Session is closed

我可以知道正确的做法吗？谢谢

Answer 1

因为会话在您等待之前已经关闭

  async with aiohttp.ClientSession() as session:
        for url in self.url_arr:
            r = self.__fetch(session, url)
            pending_req.append(r)
  #session closed hear

你可以使会话成为 __run 的参数，像这样

async def async_worker(self):
    async with aiohttp.ClientSession() as session:
        result = await self.__run(session)
        return result
    # session will close hear

async def __run(self, session):
    pending_req = []
    for url in self.url_arr:
        r = self.__fetch(session, url)
        pending_req.append(r)
    #Awaiting the results altogether instead of one by one
    result = await asyncio.wait(pending_req)
    return result

等待多个 aiohttp 请求导致 'Session is closed' 错误

Awaiting multiple aiohttp requests cause 'Session is closed' error

python

python-3.x

async-await

aiohttp