Given the following model:
from django.db import models
from django.conf import settings
class UserMessage(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL)
path = models.CharField(max_length=255)
message = models.TextField()
And given the following instance of the model:
UserMessage.objects.create(
user=request.user,
path='^/dashboard/(.*)+$',
message='Welcome to your dashboard!'
)
I want to be able to perform a lookup of the current request path against the value of UserMessage.path. This means that I need to have 'path' on the right side of my query, e.g.:
SELECT * FROM user_message WHERE '/dashboard/foo/' ~ path;
However, the Django ORM's regexp lookup produces the opposite order, e.g.:
SELECT * FROM user_message WHERE path ~ '/dashboard/foo/';
Is there a way I can easily reverse this for my desired result, using an ORM lookup? Or is this better suited for a .extra() or custom lookup expression?
答案 0 :(得分:1)
额外()
UserMessage.objects.extra(where=['%s ~ path'], params=[request.path])
自定义查找
models.py
from django.db.models import Lookup
@models.CharField.register_lookup
class NotEqual(Lookup):
lookup_name = 'test'
def as_postgresql(self, compiler, connection):
lhs, lhs_params = self.process_lhs(compiler, connection)
rhs, rhs_params = self.process_rhs(compiler, connection)
params = lhs_params + rhs_params
return '%s ~ %s' % (rhs, lhs), params
用法:UserMessages.objects.get(path__test=request.path)
答案 1 :(得分:0)
对于SQL,执行正则表达式的类似查询将是:
@CharField.register_lookup
class Matches(Lookup):
lookup_name = 'matches'
def as_sql(self, compiler, connection):
lhs, lhs_params = self.process_lhs(compiler, connection)
rhs, rhs_params = self.process_rhs(compiler, connection)
params = lhs_params + rhs_params
return '%s REGEXP %s' % (rhs, lhs), params
与
一起使用UserMessage.objects.get(path__matches=request.path)