day10: 点击注册后页面出现：网络好像出问题了 (HTTP 500)

[tianke0711]

我按照廖老师的教程，想注册一个用户名后点击提交有错误，希望帮我解决一下：
点击后页面出现：网络好像出问题了 (HTTP 500)

INFO:root:server started at http://127.0.0.1:9000...
INFO:root:Request: GET /register
INFO:root:Response handler...
INFO:root:call with args: {}
INFO:aiohttp.access:127.0.0.1 - - [14/Dec/2017:07:54:29 +0000] "GET /register HTTP/1.1" 200 6587 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/603.3.8 (KHTML, like Gecko) Version/10.1.2 Safari/603.3.8"
INFO:root:Request: POST /api/users
INFO:root:Response handler...
INFO:root:call with args: {'email': 'ka@sina.com', 'name': 'ka', 'passwd': '4ff03fb6437edad36af5fd180c42ec483983c1fc'}
/Users/k.den/awesome-python3-webapp/www/handlers.py:132: RuntimeWarning: coroutine 'Model.findAll' was never awaited
users = yield from User.findAll('email=?', [email])
ERROR:aiohttp.server:Error handling request
Traceback (most recent call last):
File "/anaconda3/lib/python3.6/site-packages/aiohttp/web_protocol.py", line 417, in start
resp = yield from self._request_handler(request)
File "/anaconda3/lib/python3.6/site-packages/aiohttp/web.py", line 289, in _handle
resp = yield from handler(request)
File "app.py", line 43, in logger
return (await handler(request))
File "app.py", line 61, in response
r = await handler(request)
File "/anaconda3/lib/python3.6/site-packages/aiohttp/web_urldispatcher.py", line 111, in handler_wrapper
result = yield from result
File "/Users/den/awesome-python3-webapp/www/coroweb.py", line 138, in call
r = yield from self._func(**kw)
File "/anaconda3/lib/python3.6/asyncio/coroutines.py", line 213, in coro
res = yield from res
File "/Users/den/awesome-python3-webapp/www/handlers.py", line 132, in api_register_user
users = yield from User.findAll('email=?', [email])
TypeError: cannot 'yield from' a coroutine object in a non-coroutine generator

[luyangong]

函数前面加async；再把yield from 改成await就行了