regex - 如何使用存储在字段值中的正则表达式执行正则表达式查找？

Question

给定以下模型:

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()

并给定以下模型实例:

UserMessage.objects.create(
    user=request.user,
    path='^/dashboard/(.*)+$',
    message='Welcome to your dashboard!'
)

我希望能够根据 UserMessage.path 的值执行当前请求路径的查找。这意味着我需要在查询的右侧有“路径”，例如:

SELECT * FROM user_message WHERE '/dashboard/foo/' ~ path;

但是，Django ORM 的正则表达式查找会产生相反的顺序，例如:

SELECT * FROM user_message WHERE path ~ '/dashboard/foo/';

有没有一种方法可以使用 ORM 查找轻松地将其反转为我想要的结果？还是这更适合 .extra() 或自定义查找表达式？

Answer 1

额外的()

UserMessage.objects.extra(where=['%s ~ path'], params=[request.path])

自定义查找

模型.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)