自定义数据库字段
扩展默认的models.CharField和models.TextField使之成为支持多语言的字段。
可以轻松实现复用，无需配置多余选项
from
django.conf import settings
from
django.db import models
from django.utils.translation import get_language
class MultilingualField(models.Field):
SUPPORTED_FIELD_TYPES = [models.CharField, models.TextField]
def __init__(self, verbose_name=None, **kwargs):
self.localized_field_model = None
for model in MultilingualField.SUPPORTED_FIELD_TYPES:
if issubclass(self.__class__, model):
self.localized_field_model = model
self._blank = kwargs.get("blank", False)
self._editable = kwargs.get("editable", True)
super().__init__(verbose_name, **kwargs)
@staticmethod
def localized_field_name(name, lang_code):
lang_code_safe = lang_code.replace("-", "_")
return f"{name}_{lang_code_safe}"
def get_localized_field(self, lang_code, lang_name):
_blank = (self._blank
if lang_code == settings.LANGUAGE_CODE
else True)
localized_field = self.localized_field_model(
f"{self.verbose_name} ({lang_name})",
name=self.name,
primary_key=self.primary_key,
max_length=self.max_length,
unique=self.unique,
blank=_blank,
null=False, # we ignore the null argument!
db_index=self.db_index,
default=self.default or "",
editable=self._editable,
serialize=self.serialize,
choices=self.choices,
help_text=self.help_text,
db_column=None,
db_tablespace=self.db_tablespace)
return localized_field
def contribute_to_class(self, cls, name,
private_only=False):
def translated_value(self):
language = get_language()
val = self.__dict__.get(
MultilingualField.localized_field_name(
name, language))
if not val:
val = self.__dict__.get(
MultilingualField.localized_field_name(
name, settings.LANGUAGE_CODE))
return val
# generate language-specific fields dynamically
if not cls._meta.abstract:
if self.localized_field_model:
for lang_code, lang_name in settings.LANGUAGES:
localized_field = self.get_localized_field(
lang_code, lang_name)
localized_field.contribute_to_class(
cls,
MultilingualField.localized_field_name(
name, lang_code))
setattr(cls, name, property(translated_value))
else:
super().contribute_to_class(
cls, name, private_only)
class MultilingualCharField(models.CharField, MultilingualField):
pass
class MultilingualTextField(models.TextField, MultilingualField):
pass
这里定义了 MultilingualCharField 和 MultilingualTextField字段
使用方法
settings.py中配置多语言
LANGUAGE_CODE = 'zh-hans'
TIME_ZONE = 'Asia/Shanghai'
LANGUAGES = (
('en-us', 'US English'),
('zh-hans', 'Asia/Shanghai')
)
默认语言设置为中文，多语言为英语
models.py中使用字段
from django.db import models
from django.utils.translation import ugettext_lazy as _
from utils.fields import (
MultilingualCharField,
MultilingualTextField
)
class Item(models.Model):
title = MultilingualCharField(_('Title'), max_length=200)
description = MultilingualTextField(_('Description'), blank=True)
content = MultilingualTextField(_('Content'))
def __str__(self):
return self.title
效果图
可以看到，数据库字段自动生成了相应语言的字段
当用户语言切换到其他，可以自动适配实现多语言
