Amin Etesamian Amin Etesamian - 1 month ago 8
Python Question

TypeErrpr is raised when using `abort(404)`

When I use

abort(status_code=404, detail='No such user', passthrough='json')

This exception is raised:

TypeError: 'NoneType' object is not iterable

This is the traceback:

File "/home/jugger/.virtualenvs/ave/lib/python3.5/site-packages/tg/appwrappers/identity.py", line 47, in __call__
return self.next_handler(controller, environ, context)
File "/home/jugger/.virtualenvs/ave/lib/python3.5/site-packages/tg/appwrappers/i18n.py", line 71, in __call__
return self.next_handler(controller, environ, context)
File "/home/jugger/.virtualenvs/ave/lib/python3.5/site-packages/tg/wsgiapp.py", line 285, in _dispatch
return controller(environ, context)
File "/home/jugger/workspace/web/ave/ave/lib/base.py", line 27, in __call__
return TGController.__call__(self, environ, context)
File "/home/jugger/.virtualenvs/ave/lib/python3.5/site-packages/tg/controllers/dispatcher.py", line 119, in __call__
response = self._perform_call(context)
File "/home/jugger/.virtualenvs/ave/lib/python3.5/site-packages/tg/controllers/dispatcher.py", line 108, in _perform_call
r = self._call(action, params, remainder=remainder, context=context)
File "/home/jugger/.virtualenvs/ave/lib/python3.5/site-packages/tg/controllers/decoratedcontroller.py", line 125, in _call
response = self._render_response(context, controller, output)
File "/home/jugger/.virtualenvs/ave/lib/python3.5/site-packages/tg/controllers/decoratedcontroller.py", line 220, in _render_response
for name in exclude_names:
TypeError: 'NoneType' object is not iterable
--------------------- >> end captured logging << ---------------------


This is my code:
I try to get an account that doesn't exist, so
NoResultFound
is caught and as the result
abort
must be done. but it raises the exception I mentioned above.

@expose('json')
def get_one(self, account_id):
"""
Get an account

:param account_id :type: str

:return Account :type: dict
"""
try:
_id = int(account_id)
except ValueError:
abort(status_code=400, detail='account_id must be int', passthrough='json')
try:
account = DBSession.query(Account).filter(Account.id == _id).one()
except NoResultFound:
abort(status_code=404, detail='No such user', passthrough='json')
return dict(
id=account.id,
username=account.username,
reputation=account.reputation,
badges=account.badges,
created=account.created,
bio=account.bio
)

Answer

according to this link, 404 is handled by the custom errors controller by default so the solution is to add expose('json') to your ErrorController and also add

if resp.content_type == 'application/json':
    return resp

after line 25 in ErrorController. This solves the issue with abort(404, passthrough='json') but I still think this is a bug and has to be fixed.

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