Python SQLAlchemy:如何在数据库中找到二级关系?
我正在为我的Flask应用程序编写一个权限系统,但在确定如何在数据库中查找关系时遇到了问题,如果你想看到一切。装饰器旨在限制对装饰视图的访问Python SQLAlchemy:如何在数据库中找到二级关系?,python,permissions,sqlalchemy,flask,flask-sqlalchemy,Python,Permissions,Sqlalchemy,Flask,Flask Sqlalchemy,我正在为我的Flask应用程序编写一个权限系统,但在确定如何在数据库中查找关系时遇到了问题,如果你想看到一切。装饰器旨在限制对装饰视图的访问 def user_has(attribute): """ Takes an attribute (a string name of either a role or an ability) and returns the function if the user has that attribute """ def wrap
def user_has(attribute):
"""
Takes an attribute (a string name of either a role or an ability) and returns the function if the user has that attribute
"""
def wrapper(func):
@wraps(func)
def inner(*args, **kwargs):
attribute_object = Role.query.filter_by(name=attribute).first() or \
Ability.query.filter_by(name=attribute).first()
if attribute_object in current_user.roles or attribute in current_user.roles.abilities.all():
return func(*args, **kwargs)
else:
# Make this do someting way better.
return "You do not have access"
return inner
return wrapper
我正在使用SQLAlchemy并在数据库中存储用户、角色和能力。用户可以有一个或多个角色。角色可以有一个或多个能力。我想获取传递给decorator的字符串,并检查用户是否具有该角色,或者用户的某个角色是否具有该能力。decorator不应该关心是否使用角色或能力参数调用它
显然,这种方法(current_user.roles.abilities.all()
)无法像我在这里试图查找abilities
那样通过我的关系数据库。我收到一条错误消息:
AttributeError: 'InstrumentedList' object has no attribute 'abilities'
如何将字符串参数与当前用户从其角色中获得的能力进行比较
作为参考,我的模型:
user_role_table = db.Table('user_role',
db.Column(
'user_id', db.Integer, db.ForeignKey('user.uid')),
db.Column(
'role_id', db.Integer, db.ForeignKey('role.id'))
)
role_ability_table = db.Table('role_ability',
db.Column(
'role_id', db.Integer, db.ForeignKey('role.id')),
db.Column(
'ability_id', db.Integer, db.ForeignKey('ability.id'))
)
class Role(db.Model):
__tablename__ = 'role'
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(120), unique=True)
abilities = db.relationship(
'Ability', secondary=role_ability_table, backref='roles')
def __init__(self, name):
self.name = name.lower()
def __repr__(self):
return '<Role {}>'.format(self.name)
def __str__(self):
return self.name
class Ability(db.Model):
__tablename__ = 'ability'
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(120), unique=True)
def __init__(self, name):
self.name = name.lower()
def __repr__(self):
return '<Ability {}>'.format(self.name)
def __str__(self):
return self.name
class User(db.Model):
__tablename__ = 'user'
uid = db.Column(db.Integer, primary_key=True)
email = db.Column(db.String(120), unique=True)
pwdhash = db.Column(db.String(100))
roles = db.relationship('Role', secondary=user_role_table, backref='users')
def __init__(self, email, password, roles=None):
self.email = email.lower()
# If only a string is passed for roles, convert it to a list containing
# that string
if roles and isinstance(roles, basestring):
roles = [roles]
# If a sequence is passed for roles (or if roles has been converted to
# a sequence), fetch the corresponding database objects and make a list
# of those.
if roles and is_sequence(roles):
role_list = []
for role in roles:
role_list.appen(Role.query.filter_by(name=role).first())
self.roles = role_list
# Otherwise, assign the default 'user' role. Create that role if it
# doesn't exist.
else:
r = Role.query.filter_by(name='user').first()
if not r:
r = Role('user')
db.session.add(r)
db.session.commit()
self.roles = [r]
self.set_password(password)
def set_password(self, password):
self.pwdhash = generate_password_hash(password)
def check_password(self, password):
return check_password_hash(self.pwdhash, password)
def is_authenticated(self):
return True
def is_active(self):
return True
def is_anonymous(self):
return False
def get_id(self):
return unicode(self.uid)
def __repr__(self):
return '<User {}>'.format(self.email)
def __str__(self):
return self.email
有没有可能因为在if语句的第二个子句中使用了
attribute
而不是attribute\u object
,所以这不起作用
与此相反:
if attribute_object in current_user.roles or attribute in current_user.roles.abilities.all():
试试这个:
if attribute_object in current_user.roles or attribute_object in current_user.roles.abilities.all():
有没有可能因为在if语句的第二个子句中使用了
attribute
而不是attribute\u object
,所以这不起作用
与此相反:
if attribute_object in current_user.roles or attribute in current_user.roles.abilities.all():
试试这个:
if attribute_object in current_user.roles or attribute_object in current_user.roles.abilities.all():
解决方案最终变得非常简单。我觉得从一开始就不知道有点傻
user_abilities = []
for role in current_user.roles:
user_abilities += [role.ability for ability in role.abilities]
我仍然觉得可能有更好的解决方案,但解决方案毫无问题。解决方案最终变得非常简单。我觉得从一开始就不知道有点傻
user_abilities = []
for role in current_user.roles:
user_abilities += [role.ability for ability in role.abilities]
我仍然觉得可能有更好的模式,但解决方案可以顺利运行。这是一个好问题。我已经解决了,但是我仍然有以前遇到的问题<代码>属性错误:“InstrumentedList”对象没有属性“能力”它告诉我,这不是访问与用户角色相关的能力的方法,但我不知道正确的方法。这是一个好问题。我已经解决了,但是我仍然有以前遇到的问题<代码>属性错误:“InstrumentedList”对象没有属性“能力”它告诉我,这不是访问与用户角色相关的能力的方法,但我不知道正确的方法。