2

我试图让 flask-restful 返回一个 datetime 字段，但是它会出现错误：

MarshallingException: 'datetime.date' object has no attribute 'utctimetuple'

模型（sqlalchemy）如下：

class Target(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    uuid = db.Column(db.String(256))
    title = db.Column(db.String(80))
    description = db.Column(db.String(250))
    done = db.Column(db.Boolean, default = False)
    startDate = db.Column(db.DateTime, default=datetime.utcnow)
    timeDuration = db.Column(db.Integer, default = 0)
    isActive = db.Column(db.Boolean, default = True)

目标字段是：

target_fields = {
    'id': fields.Integer,
    'uuid' : fields.String,
    'title': fields.String,
    'description': fields.String,
    'done': fields.Boolean,
    'startDate' : fields.DateTime
#    'uri': fields.Url('target')
}

实际的剩余资源是：

class TargetAPI(Resource):
    decorators = [auth.login_required]

    def __init__(self):
        self.reqparse = reqparse.RequestParser()
        self.reqparse.add_argument('title', type = str, location = 'json')
        self.reqparse.add_argument('description', type = str, location = 'json')
        self.reqparse.add_argument('done', type = bool, location = 'json')
        self.reqparse.add_argument('startDate', type = datetime, location = 'json')
        self.reqparse.add_argument('timeDuration', type = int, location = 'json')
        self.reqparse.add_argument('isActive', type = bool, location = 'json')
        super(TargetAPI, self).__init__()

    def get(self,username, id):

        target = Target.query.get(id)
        if not target:
            abort(404)

        return { 'target': marshal(target, target_fields) }

完整的堆栈跟踪是：

Traceback (most recent call last):
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1836, in __call__
    return self.wsgi_app(environ, start_response)
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1820, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/usr/local/lib/python2.7/site-packages/flask_restful/__init__.py", line 258, in error_router
    return original_handler(e)
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1403, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1817, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1477, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/local/lib/python2.7/site-packages/flask_restful/__init__.py", line 258, in error_router
    return original_handler(e)
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1381, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1461, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/usr/local/lib/python2.7/site-packages/flask_restful/__init__.py", line 397, in wrapper
    resp = resource(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/flask_httpauth.py", line 53, in decorated
    return f(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/flask/views.py", line 84, in view
    return self.dispatch_request(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/flask_restful/__init__.py", line 487, in dispatch_request
    resp = meth(*args, **kwargs)
  File "/Users/nahuel/proj/ptcp/app/resources/targetListAPI.py", line 60, in post
    'target': marshal(newTarget, target_fields) }, 201
  File "/usr/local/lib/python2.7/site-packages/flask_restful/__init__.py", line 533, in marshal
    return OrderedDict(items)
  File "/usr/local/Cellar/python/2.7.6_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/collections.py", line 52, in __init__
    self.__update(*args, **kwds)
  File "/usr/local/Cellar/python/2.7.6_1/Frameworks/Python.framework/Versions/2.7/lib/python2.7/_abcoll.py", line 547, in update
    for key, value in other:
  File "/usr/local/lib/python2.7/site-packages/flask_restful/__init__.py", line 532, in <genexpr>
    for k, v in fields.items())
  File "/usr/local/lib/python2.7/site-packages/flask_restful/fields.py", line 109, in output
    return self.format(value)
  File "/usr/local/lib/python2.7/site-packages/flask_restful/fields.py", line 271, in format
    raise MarshallingException(ae)

我一生都无法理解为什么要访问 datetime.date，因为我总是使用 datetime.datetime 对象！有任何想法吗？

4

1 回答 1

2

终于解决了问题！为了完整起见，我将发布答案：本质上，问题在于下面的 postgresql 数据库对“startDate”字段使用日期类型，而不是时间戳。因此，当 sqlalchemy 检索 Target.startDate 对象时，它为其分配了 datetime.date 类型，而不是 datetime.datetime。

前：

                                                  Table "public.target"
    Column    |          Type          |                      Modifiers                      | Storage  | Stats target | Description
--------------+------------------------+-----------------------------------------------------+----------+--------------+-------------
 id           | integer                | not null default nextval('target_id_seq'::regclass) | plain    |              |
 uuid         | character varying(256) |                                                     | extended |              |
 title        | character varying(80)  |                                                     | extended |              |
 description  | character varying(250) |                                                     | extended |              |
 done         | boolean                |                                                     | plain    |              |
 startDate    | date                   |                                                     | plain    |              |
 timeDuration | integer                |                                                     | plain    |              |
 isActive     | boolean                |                                                     | plain    |              |
 userId       | integer                |                                                     | plain    |              |

后：

 startDate    | timestamp without time zone |                                                     | plain    |              |
于 2014-07-30T10:08:53.973 回答