objects.py 文件源码

def default(self, obj):
        if isinstance(obj.__class__, DeclarativeMeta):
            # an SQLAlchemy class
            fields = {}
            for field in [x for x in dir(obj) if not x.startswith('_') 
                                and x != 'metadata' and x != '_sa_instance_state']:
                data = obj.__getattribute__(field)

                if isinstance(data, types.MethodType):
                    continue

                try:
                    json.dumps(data) # this will fail on non-encodable values, like other classes
                    fields[field] = data
                except TypeError:
                    try:
                        fields[field] = [str(d) for d in data]
                    except:
                        fields[field] = None
                except UnicodeEncodeError:
                    fields[field] = 'Non-encodable'
            # a json-encodable dict
            return fields

        return json.JSONEncoder.default(self, obj)