我在尝试实例化我的用户模型时收到断言错误。在下面的堆栈跟踪中，我省略了将请求调度到请求处理程序。
File "/Users/frederikcreemers/jsbeast/users.py", line 68, in get
User(nickname=nickname,user=users.get_current_user()).put()
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/model.py", line 2926, in _put
return self._put_async(**ctx_options).get_result()
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/tasklets.py", line 322, in get_result
self.check_success()
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/tasklets.py", line 317, in check_success
self.wait()
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/tasklets.py", line 301, in wait
if not ev.run1():
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/eventloop.py", line 219, in run1
delay = self.run0()
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/eventloop.py", line 181, in run0
callback(*args, **kwds)
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/context.py", line 170, in _finished_callback
fut.check_success()
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/tasklets.py", line 362, in _help_tasklet_along
value = gen.send(val)
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/context.py", line 268, in _put_tasklet
keys = yield self._conn.async_put(options, datastore_entities)
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/datastore/datastore_rpc.py", line 1550, in async_put
pbs = [self.__adapter.entity_to_pb(entity) for entity in entities]
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/model.py", line 548, in entity_to_pb
pb = ent._to_pb()
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/model.py", line 2719, in _to_pb
prop._serialize(self, pb)
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/model.py", line 1245, in _serialize
values = self._get_base_value_unwrapped_as_list(entity)
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/model.py", line 1034, in _get_base_value_unwrapped_as_list
wrapped = self._get_base_value(entity)
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/model.py", line 1022, in _get_base_value
return self._apply_to_values(entity, self._opt_call_to_base_type)
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/model.py", line 1186, in _apply_to_values
newvalue = function(value)
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/model.py", line 1065, in _opt_call_to_base_type
value = _BaseValue(self._call_to_base_type(value))
File "/Applications/GoogleAppEngineLauncher.app/Contents/Resources/GoogleAppEngine-default.bundle/Contents/Resources/google_appengine/google/appengine/ext/ndb/model.py", line 599, in __init__
assert not isinstance(b_val, list), repr(b_val)
AssertionError: []
发生这种情况的代码如下所示：
class LoginHandler(webapp2.RequestHandler):
def get(self):
url = self.request.get('url')
if not url:
url = "/"
if User.current():
self.redirect(url)
else:
if users.get_current_user():
nickname = self.request.get("nickname")
if(not nickname):
self.response.out.write(views.render("nickname"))
return
else:
errors = []
if len(nickname) < 3:
errors.append("Your nickname should be at least 3 characters long.")
if(len(nickname) > 15):
errors.append("Your nickname should not be longer than 15 characters.")
import re
if not re.match(r"[0-9a-zA-Z_.]+$",nickname):
errors.append("Your nickname can only contain small and capital letters, numbers, underscores and dots.")
if len(errors) == 0 and User.by_nickname(nickname):
errors.append("The name "+nickname+" is already in use.")
if len(errors) == 0:
import logging
User(nickname=nickname,user=users.get_current_user()).put()
self.redirect(url)
else:
self.response.out.write(views.render('nickname',{'errors':errors}))
return
else:
self.redirect(users.create_login_url("/user/login",federated_identity=self.request.get('provider')))
请注意，尽管我导入google.appengine.api.users但该模块中的用户 objecvt 仍保存在 users 命名空间中，因此不会存在冲突。
这是用户模型的样子：
class User(ndb.Model):
nickname = ndb.StringProperty()
email = ndb.StringProperty()
user = ndb.UserProperty()
num_solved_problems = ndb.ComputedProperty(lambda self: problems.Attempt.query().filter(problems.Attempt.user == self.user,problems.Attempt.correct == True).count())
solved_problems = ndb.ComputedProperty(lambda self:problems.Attempt.query().filter(problems.Attempt.user == self.user,problems.Attempt.correct == True).fetch())
@classmethod
def current(cls):
if not users.get_current_user():
return None
return cls.query().filter(User.user == users.get_current_user()).get()
@classmethod
def by_nickname(cls,nickname):
return cls.query().filter(User.nickname == nickname).get()
我的猜测是 ComputedProperty solved_problems需要说 repeated=True，因为 fetch（） 返回了一个列表。
附言。不是你的错，但是当SO坚持显示水平滚动条时，很难阅读代码示例。