我试图使用alchimia获取DB的异步API。试图向DB发出一个简单的请求，如：
def authorization(self, data):
"""
Checking user with DB
"""
def __gotResult(user):
yield engine.execute(sqlalchemy.select([Users]).where(Users.name == user))
result = __gotResult(data['user'])
log.msg("[AUTH] User=%s trying to auth..." % data['user'])
data, result_msg = commands.AUTH(result, data)
log.msg(result_msg)
return data
并且无法理解 - 我做错了什么？也许在发动机选项中出现问题（其中reactor = []）？
源代码：
import sys
from json import dumps, loads
import sqlalchemy
from twisted.internet import reactor, ssl
from twisted.python import log, logfile
from twisted.web.server import Site
from twisted.web.static import File
from autobahn.twisted.websocket import WebSocketServerFactory, WebSocketServerProtocol, listenWS
import commands
from db.tables import Users
from alchimia import TWISTED_STRATEGY
log_file = logfile.LogFile("service.log", ".")
log.startLogging(log_file)
engine = sqlalchemy.create_engine('postgresql://test:test@localhost/testdb', pool_size=20, max_overflow=0,strategy=TWISTED_STRATEGY, reactor=[])
class DFSServerProtocol(WebSocketServerProtocol):
commands = commands.commands_user
def __init__(self):
self.commands_handlers = self.__initHandlersUser()
def __initHandlersUser(self):
handlers = commands.commands_handlers_server
handlers['AUTH'] = self.authorization
handlers['READ'] = None
handlers['WRTE'] = None
handlers['DELT'] = None
handlers['RNME'] = None
handlers['SYNC'] = None
handlers['LIST'] = None
return handlers
def authorization(self, data):
"""
Checking user with DB
"""
def __gotResult(user):
yield engine.execute(sqlalchemy.select([Users]).where(Users.name == data['user']))
result = __gotResult(data['user'])
log.msg("[AUTH] User=%s trying to auth..." % data['user'])
data, result_msg = commands.AUTH(result, data)
log.msg(result_msg)
return data
def onMessage(self, payload, isBinary):
json_data = loads(payload)
json_auth = json_data['auth']
json_cmd = json_data['cmd']
if json_auth == False:
if json_cmd == 'AUTH':
json_data = self.commands_handlers['AUTH'](json_data)
# for authorized users
else:
if json_cmd in commands.commands_user.keys():
if self.commands_handlers[json_cmd] is not None:
json_data = self.commands_handlers[json_cmd](json_data)
else:
json_data['error'] = '%s command is not already realized...' % json_cmd
else:
json_data['auth'] = False
json_data['error'] = 'This command is not supported on server...'
response = dumps(json_data)
self.sendMessage(str(response))
if __name__ == '__main__':
if len(sys.argv) > 1 and sys.argv[1] == 'debug':
log.startLogging(sys.stdout)
debug = True
else:
debug = False
contextFactory = ssl.DefaultOpenSSLContextFactory('keys/server.key', 'keys/server.crt')
factory = WebSocketServerFactory("wss://localhost:9000", debug = debug, debugCodePaths = debug)
factory.protocol = DFSServerProtocol
factory.setProtocolOptions(allowHixie76 = True)
listenWS(factory, contextFactory)
webdir = File("./web/")
webdir.contentTypes['.crt'] = 'application/x-x509-ca-cert'
web = Site(webdir)
reactor.listenSSL(8080, web, contextFactory)
#reactor.listenTCP(8080, web)
reactor.run()
追溯：
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/twisted/python/log.py", line 88, in callWithLogger
return callWithContext({"system": lp}, func, *args, **kw)
File "/usr/local/lib/python2.7/dist-packages/twisted/python/log.py", line 73, in callWithContext
return context.call({ILogContext: newCtx}, func, *args, **kw)
File "/usr/local/lib/python2.7/dist-packages/twisted/python/context.py", line 118, in callWithContext
return self.currentContext().callWithContext(ctx, func, *args, **kw)
File "/usr/local/lib/python2.7/dist-packages/twisted/python/context.py", line 81, in callWithContext
return func(*args,**kw)
--- <exception caught here> ---
File "/usr/local/lib/python2.7/dist-packages/twisted/internet/posixbase.py", line 614, in _doReadOrWrite
why = selectable.doRead()
File "/usr/local/lib/python2.7/dist-packages/twisted/internet/tcp.py", line 215, in doRead
return self._dataReceived(data)
File "/usr/local/lib/python2.7/dist-packages/twisted/internet/tcp.py", line 221, in _dataReceived
rval = self.protocol.dataReceived(data)
File "/usr/local/lib/python2.7/dist-packages/twisted/protocols/tls.py", line 419, in dataReceived
self._flushReceiveBIO()
File "/usr/local/lib/python2.7/dist-packages/twisted/protocols/tls.py", line 389, in _flushReceiveBIO
ProtocolWrapper.dataReceived(self, bytes)
File "/usr/local/lib/python2.7/dist-packages/twisted/protocols/policies.py", line 120, in dataReceived
self.wrappedProtocol.dataReceived(data)
File "/usr/local/lib/python2.7/dist-packages/autobahn/twisted/websocket.py", line 78, in dataReceived
self._dataReceived(data)
File "/usr/local/lib/python2.7/dist-packages/autobahn/websocket/protocol.py", line 1270, in _dataReceived
self.consumeData()
File "/usr/local/lib/python2.7/dist-packages/autobahn/websocket/protocol.py", line 1286, in consumeData
while self.processData() and self.state != WebSocketProtocol.STATE_CLOSED:
File "/usr/local/lib/python2.7/dist-packages/autobahn/websocket/protocol.py", line 1445, in processData
return self.processDataHybi()
File "/usr/local/lib/python2.7/dist-packages/autobahn/websocket/protocol.py", line 1758, in processDataHybi
fr = self.onFrameEnd()
File "/usr/local/lib/python2.7/dist-packages/autobahn/websocket/protocol.py", line 1887, in onFrameEnd
self._onMessageEnd()
File "/usr/local/lib/python2.7/dist-packages/autobahn/twisted/websocket.py", line 107, in _onMessageEnd
self.onMessageEnd()
File "/usr/local/lib/python2.7/dist-packages/autobahn/websocket/protocol.py", line 734, in onMessageEnd
self._onMessage(payload, self.message_is_binary)
File "/usr/local/lib/python2.7/dist-packages/autobahn/twisted/websocket.py", line 110, in _onMessage
self.onMessage(payload, isBinary)
File "server.py", line 84, in onMessage
json_data = self.commands_handlers['AUTH'](json_data)
File "server.py", line 68, in authorization
data, result_msg = commands.AUTH(result, data)
File "/home/relrin/code/Helenae/helenae/commands.py", line 68, in AUTH
if result['name'] == data['user']:
exceptions.TypeError: 'generator' object has no attribute '__getitem__'
答案 0 :(得分：1)
我认为你错过@inlineCallbacks周围的__gotResult()但是这对你来说可能没什么帮助;因为用inlineCallbacks包装的单个语句生成器有点无意义。无论如何，您应该习惯使用显式延迟处理。让我们分开：
def authorization(self, data):
"""
Checking user with DB
"""
# engine.execute already gives us a deferred, will grab on to that.
user = data['user']
result_d = engine.execute(sqlalchemy.select([Users]).where(Users.name == user))
# we don't have the result in authorization,
# we need to wrap any code that works with its result int a callback.
def result_cb(result):
data, result_msg = commands.AUTH(result, data)
return data
result_d.addCallback(result_cb)
# we want to pass the (asynchronous) result out, it's hiding in our deferred;
# so we return *that* instead; callers need to add more callbacks to it.
return result_d
如果你坚持;我们可以把它压缩成内联回调形式：
from twisted.internet.defer import inlineCallbacks, returnValue
@inlineCallbacks
def authorization(self, data):
user = data['user']
result = yield engine.execute(sqlalchemy.select([Users]).where(Users.name == user))
data, result_msg = commands.AUTH(result, data)
yield returnValue(data)
authorization()是异步的;并且必须是因为engine.execute是异步的。要使用它，你必须将一个回调附加到它返回的延迟（尽管调用者也可以产生它，如果它也包含在inlineCallbacks 中