Django 模型：是否可以使用管理器为特定字段强制 filter/get 上的 icontains？

Question

假设我有一个带有类似于此字符串字段的模型

class Product(models.Model):
    upc = models.CharField(max_length=12, blank=False, null=False)

是否可以构建一个模型管理器或类似的东西，每次我使用 Product.objects.get/Product.objects.filter 它都会覆盖默认查找以强制 search/filter 表现得像我一样使用 icontains?

如：

Product.objects.get(upc="012345678902")
Product.objects.filter(upc="012345678902")

默认情况下的行为如下：

Product.objects.get(upc__icontains="012345678902")
Product.objects.filter(upc__icontains="012345678902")

Answer 1

您可以自定义查询管理器或查询集，并覆盖 get/filter 方法。下面的演示可以告诉您如何自定义查询管理器实现强制图标。

from django.db import models


class ForceIContainsManager(models.Manager):
    force_icontains_fields = None

    def __init__(self, *args, **kwargs) -> None:
        if "force_icontains_fields" in kwargs:
            self.force_icontains_fields = kwargs.pop("force_icontains_fields")
        super(ForceIContainsManager, self).__init__(*args, **kwargs)

    def get(self, *args, **kwargs):
        kwargs = self._force_icontains(**kwargs)
        return super(ForceIContainsManager, self).get(*args, **kwargs)

    def filter(self, *args, **kwargs):
        kwargs = self._force_icontains(**kwargs)
        return super(ForceIContainsManager, self).filter(*args, **kwargs)

    def _force_icontains(self, **kwargs):
        """
        replace field in force_icontains_fields to icontains style
        """
        if not self.force_icontains_fields:
            return kwargs
        for field in self.force_icontains_fields:
            if field in kwargs:
                v = kwargs.pop(field)
                new_field_name = '%s__icontains' % field
                kwargs[new_field_name] = v
        return kwargs


class YourModel(models.Model):
    # define a another manager, YourModel.manager will force icontains on certain fields
    manager = ForceIContainsManager(
        force_icontains_fields=["field1", "field2"])
    # if you want use YourModel.objects, you should uncomment below
    # objects = ForceIContainsManager(force_icontains_fields=["field1", "field2"])
    pass


# check sql
print(YourModel.manager.filter(field1='test').query)

更多定制可以看https://sodocumentation.net/django/topic/1400/custom-managers-and-querysets

QueryManager 代理了QuerySet 中的所有方法BaseManager.from_queryset，选择一个就够了。

Django 模型：是否可以使用管理器为特定字段强制 filter/get 上的 icontains？

Django models: is it possible to force icontains on filter/get for specific field using a manager?

python

django

django-models

django-orm