我最近问这个问题自定义 Django MultilingualTextField 模型字段 https://stackoverflow.com/questions/16750509/custom-django-multilingualtextfield-model-field但我发现没有充分的理由为什么我不应该这样做，所以我创建了一个支持多语言文本的模型字段，自动返回当前语言的文本。这基本上是以 json 格式将自定义语言对象存储到数据库的字段。这是代码：
Github: https://github.com/james4388/django-multilingualfield https://github.com/james4388/django-multilingualfield
Ussage:
from django.db import models
from multilingualfield import MLTextField, MLHTMLField
class MyModel(models.Model):
text = MLTextField()
html = MLHTMLField()
像普通文本字段一样使用它，翻译是根据系统语言自动进行的（translation.get_language）
>>>from django.utils import translation
>>>translation.active('en')
>>>m = MyModal.objects.create(text='Hello world',html='<b>Hello world</b>');
>>>m.text
Hello world
>>>translation.active('fr')
>>>m.text #Auto fallback to first language (if any).
Hello world
>>>m.text.value('Bonjour')
>>>m.text.value('Ciao','es')
>>>m.text
Bonjour
>>>m.save()
>>>m.text.get_available_language()
['en', 'fr', 'es']
>>>m.text.remove_language('en')
Field.py
from __future__ import unicode_literals
from django.core.exceptions import ValidationError
from django.conf import settings
from django.db import models, DatabaseError, transaction
from django.utils.translation import ugettext_lazy as _, get_language
from django.utils import six
try:
import json
except ImportError:
from django.utils import simplejson as json
def get_base_language(lang):
if '-' in lang:
return lang.split('-')[0]
return lang
def get_current_language(base=True):
l = get_language()
if base:
return get_base_language(l)
return l
from .widgets import MultilingualWidget, MultilingualHTMLWidget
from .forms import MultilingualTextFormField, MultilingualHTMLFormField
from .language import LanguageText
class MultilingualTextField(six.with_metaclass(models.SubfieldBase, models.Field)):
"""
A field that support multilingual text for your model
"""
default_error_messages = {
'invalid': _("'%s' is not a valid JSON string.")
}
description = "Multilingual text field"
def __init__(self, *args, **kwargs):
self.lt_max_length = kwargs.pop('max_length',-1)
self.default_language = kwargs.get('default_language', get_current_language())
super(MultilingualTextField, self).__init__(*args, **kwargs)
def formfield(self, **kwargs):
defaults = {
'form_class': MultilingualTextFormField,
'widget': MultilingualWidget
}
defaults.update(**kwargs)
return super(MultilingualTextField, self).formfield(**defaults)
def validate(self, value, model_instance):
if not self.null and value is None:
raise ValidationError(self.error_messages['null'])
try:
self.get_prep_value(value)
except:
raise ValidationError(self.error_messages['invalid'] % value)
def get_internal_type(self):
return 'TextField'
def db_type(self, connection):
return 'text'
def to_python(self, value):
if isinstance(value, six.string_types):
if value == "" or value is None:
if self.null:
return None
if self.blank:
return ""
try:
valuejson = json.loads(value)
Lang = LanguageText(max_length=self.lt_max_length,default_language=self.default_language)
Lang.values = valuejson
return Lang
except ValueError:
try:
Lang = LanguageText(value,language=None,max_length=self.lt_max_length,default_language=self.default_language)
return Lang
except:
msg = self.error_messages['invalid'] % value
raise ValidationError(msg)
return value
def get_db_prep_value(self, value, connection=None, prepared=None):
return self.get_prep_value(value)
def get_prep_value(self, value):
if value is None:
if not self.null and self.blank:
return ""
return None
if isinstance(value, six.string_types):
value = LanguageText(value,language=None,max_length=self.lt_max_length,default_language=self.default_language)
if isinstance(value, LanguageText):
value.max_length = self.lt_max_length
value.default_language = self.default_language
return json.dumps(value.values)
return None
def get_prep_lookup(self, lookup_type, value):
if lookup_type in ["exact", "iexact"]:
return self.to_python(self.get_prep_value(value))
if lookup_type == "in":
return [self.to_python(self.get_prep_value(v)) for v in value]
if lookup_type == "isnull":
return value
if lookup_type in ["contains", "icontains"]:
if isinstance(value, (list, tuple)):
raise TypeError("Lookup type %r not supported with argument of %s" % (
lookup_type, type(value).__name__
))
# Need a way co combine the values with '%', but don't escape that.
return self.get_prep_value(value)[1:-1].replace(', ', r'%')
if isinstance(value, dict):
return self.get_prep_value(value)[1:-1]
return self.to_python(self.get_prep_value(value))
raise TypeError('Lookup type %r not supported' % lookup_type)
def value_to_string(self, obj):
return self._get_val_from_obj(obj)
Forms.py
from django import forms
from django.utils import simplejson as json
from .widgets import MultilingualWidget, MultilingualHTMLWidget
from .language import LanguageText
class MultilingualTextFormField(forms.CharField):
widget = MultilingualWidget
def __init__(self, *args, **kwargs):
kwargs['widget'] = MultilingualWidget
super(MultilingualTextFormField, self).__init__(*args, **kwargs)
def clean(self, value):
"""
The default is to have a TextField, and we will decode the string
that comes back from this. However, another use of this field is
to store a list of values, and use these in a MultipleSelect
widget. So, if we have an object that isn't a string, then for now
we will assume that is where it has come from.
"""
value = super(MultilingualTextFormField, self).clean(value)
if not value:
return value
if isinstance(value, basestring):
try:
valuejson = json.loads(value)
Lang = LanguageText()
Lang.values = valuejson
return Lang
except ValueError:
try:
Lang = LanguageText(value,language=None)
return Lang
except:
raise forms.ValidationError(
'JSON decode error: %s' % (unicode(exc),)
)
else:
return value
language.py 中的语言对象
from __future__ import unicode_literals
from django.core.exceptions import ValidationError
from django.conf import settings
from django.db import models, DatabaseError, transaction
from django.utils.translation import ugettext_lazy as _, get_language
try:
import json
except ImportError:
from django.utils import simplejson as json
def get_base_language(lang):
if '-' in lang:
return lang.split('-')[0]
return lang
def get_current_language(base=True):
l = get_language()
if base:
return get_base_language(l)
return l
class LanguageText(object):
'''
JSON text field blah blah blah
'''
values = {}
default_language = None
max_length = -1
def __init__(self, value=None, language=None, default_language=None, max_length=-1):
self.max_length = max_length
self.default_language = default_language
self.values = {}
if value is not None:
self.value(value,language)
def __call__(self, value=None, language=None):
self.value(value,language)
return self
def get_available_language(self):
return self.values.keys()
def get_current_language(self, base=False):
return get_current_language(base)
def remove_language(self, lang):
try:
return self.values.pop(lang)
except:
pass
def has_language(self, lang):
return self.values.has_key(lang)
def get(self, language=None, fallback=True):
if language is None:
curr_lang = get_current_language(False)
else:
curr_lang = language
curr_lang_base = get_current_language(True)
if curr_lang in self.values:
return self.values[curr_lang]
if not fallback:
return None
if curr_lang_base in self.values:
return self.values[curr_lang_base]
if self.default_language in self.values:
return self.values[self.default_language]
try:
first_lang = self.values.keys()[0]
return self.values[first_lang]
except:
pass
return None
def value(self, value=None, language=None):
if value is None: #Get value
return self.get(language)
else: #Set value
if language is None:
language = get_current_language(False)
if self.max_length != -1:
value = value[:self.max_length]
self.values[language] = value
return None
def __unicode__(self):
return self.value()
def __str__(self):
return unicode(self.value()).encode('utf-8')
def __repr__(self):
return unicode(self.value()).encode('utf-8')
小部件.py
from django import forms
from django.utils import simplejson as json
from django.conf import settings
from .language import LanguageText
from django.template import loader, Context
class MultilingualWidget(forms.Textarea):
def __init__(self, *args, **kwargs):
forms.Widget.__init__(self, *args, **kwargs)
def render(self, name, value, attrs=None):
if value is None: #New create or edit none
vjson = '{}'
aLang = []
Lang = '[]'
Langs = json.dumps(dict(settings.LANGUAGES))
t = loader.get_template('multilingualtextarea.html')
c = Context({"data":value,"vjson":vjson,"lang":Lang,"langs":Langs,"langobjs":settings.LANGUAGES,"fieldname":name})
return t.render(c)
if isinstance(value, LanguageText):
vjson = json.dumps(value.values)
aLang = value.get_available_language()
Lang = json.dumps(aLang)
Langs = json.dumps(dict(settings.LANGUAGES))
t = loader.get_template('multilingualtextarea.html')
c = Context({"data":value,"vjson":vjson,"lang":Lang,"langs":Langs,"langobjs":settings.LANGUAGES,"fieldname":name})
return t.render(c)
return "Invalid data '%s'" % value
所以我想知道这是一个好方法吗？为什么我不应该这样做？请帮忙
