root/plesonet_multilanguage/trunk/locale.py

from django.utils.cache import patch_vary_headers
from django.utils import translation
from string import split
from django.conf import settings
import datetime
from django.http import HttpResponseNotFound
from django.template.loader import render_to_string
from django.template import RequestContext

LANGUAGE_COOKIE_KEY = 'site_language'

class LocaleMiddleware(object):

    def process_request(self, request):
        # get language from URL
        # split returns something like this: ['', 'ru', 'blog', '']
        language = split(request.path, '/')[1]
        if language is not None and len(language) == 2:
            if not self.is_language_exists(language):
                translation.activate(settings.LANGUAGE_CODE)
                request.LANGUAGE_CODE = translation.get_language()
                return HttpResponseNotFound(render_to_string("404.html", RequestContext(request)))
        # get language from cookies
        if not translation.check_for_language(language):
            if request.COOKIES.has_key(LANGUAGE_COOKIE_KEY):
                language = request.COOKIES[LANGUAGE_COOKIE_KEY]
        # get language from request
        if not translation.check_for_language(language):
            language = translation.get_language_from_request(request)
        # get default language from settings
        if not translation.check_for_language(language):
            language = settings.LANGUAGE_CODE
        translation.activate(language)
        request.LANGUAGE_CODE = translation.get_language()

    def process_response(self, request, response):
        patch_vary_headers(response, ('Accept-Language',))
        response['Content-Language'] = translation.get_language()
        # set language cookie
        max_age = 60 * 60 * 24 * 365
        expires = datetime.datetime.strftime(datetime.datetime.utcnow() + datetime.timedelta(seconds=max_age), "%a, %d-%b-%Y %H:%M:%S GMT")
        response.set_cookie(key = LANGUAGE_COOKIE_KEY, value = translation.get_language(), max_age = max_age, expires = expires)
        return response
    
    def is_language_exists(self, language):
        for l in settings.LANGUAGES:
            if l[0] == language:
                return True
        return False