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python - 等待多个 aiohttp 请求导致“会话已关闭”错误

问题描述

我正在编写一个辅助类，用于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}

在异步中，一一等待结果似乎毫无意义。我将它们放入一个数组中，然后一起等待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

在 __fetch async with session.get(url) 作为响应： RuntimeError: Session is closed

我可以知道正确的方法吗？谢谢。

标签： pythonpython-3.xasync-awaitaiohttp

解决方案

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

你可以让 session 成为一个参数__run，就像这样

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

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