pythonpython-asyncio

python-asyncio TypeError: object dict can't be used in 'await' expression


I am using a third party module to retrieve data from an API. I simply would like to asynchronously await the module to return the data which occasionally takes several seconds and freezes up my app. However, when I try to await a call to that module I receive the TypeError:

TypeError: object dict can't be used in 'await' expression

import thirdPartyAPIwrapper

async def getData():
    retrienveData = await thirdPartyAPIWrapper.data()
    return await retrieveData

def main():
    loop = asncio.get_event_loop()
    data = loop.run_until_complete(getData())
    loop.close
    return data

Why can I not await a type('dict')? Is there a way around this? If async/await with asyncio will not work with a third party module that doesn't return a coroutine then what are my other options?


Solution

  • Only asynchronous (defined with async def) functions can be awaited. Whole idea is that such functions are written special way what makes possible to run (await) them without blocking event loop.

    If you want to get result from common (defined with def) function that takes some considerable time to be executed you have these options:

    Usually you want to choose second option.

    Here's example of how to do it:

    import asyncio
    import time
    from concurrent.futures import ThreadPoolExecutor
    
    
    _executor = ThreadPoolExecutor(1)
    
    
    def sync_blocking():
        time.sleep(2)
    
    
    async def hello_world():
        # run blocking function in another thread,
        # and wait for it's result:
        await loop.run_in_executor(_executor, sync_blocking)
    
    
    loop = asyncio.get_event_loop()
    loop.run_until_complete(hello_world())
    loop.close()
    

    Please, read this answer about how asyncio works. I think it'll help you much.