andretw/:customize-your-mezzanine-with-Django-middleware-and-JavaScript-AngularJS-for-i18n-multilingual.html

## :customize-your-mezzanine-with-Django-middleware-and-JavaScript-AngularJS-for-i18n-multilingual.html
This Gist is for my post: http://www.andretw.com/2014/04/customize-your-mezzanine-with-Django-middleware-and-JavaScript-AngularJS-for-i18n-multilingual.html

## add_middleware_in_settings.py
# List of middleware classes to use. Order is important; in the request phase,
# these middleware classes will be applied in the order given, and in the
# response phase the middleware will be applied in reverse order.
MIDDLEWARE_CLASSES = (
    "mezzanine.core.middleware.UpdateCacheMiddleware",
    "django.contrib.sessions.middleware.SessionMiddleware",
    "django.middleware.locale.LocaleMiddleware",

    # Add the following line into MIDDLEWARE_CLASSES
    "plusdiff.middleware.SelectLangMiddleware",

    "django.contrib.auth.middleware.AuthenticationMiddleware",
    "django.middleware.common.CommonMiddleware",
    "django.middleware.csrf.CsrfViewMiddleware",
    "django.contrib.messages.middleware.MessageMiddleware",
    "mezzanine.core.request.CurrentRequestMiddleware",
    "mezzanine.core.middleware.RedirectFallbackMiddleware",
    "mezzanine.core.middleware.TemplateForDeviceMiddleware",
    "mezzanine.core.middleware.TemplateForHostMiddleware",
    "mezzanine.core.middleware.AdminLoginInterfaceSelectorMiddleware",
    "mezzanine.core.middleware.SitePermissionMiddleware",
    # Uncomment the following if using any of the SSL settings:
    # "mezzanine.core.middleware.SSLRedirectMiddleware",
    "mezzanine.pages.middleware.PageMiddleware",
    "mezzanine.core.middleware.FetchFromCacheMiddleware",
)

## base.html
<html>
<head>
<!-- Don't forget to inclue AngularJS, jQuery, etc. -->
<script src="{% static "langpack/" %}{{ LANG }}.js"></script>
</head>

<body>
  ${ _("This Sentence needs to be translated.") }$
</body>

</html>

## interpolate.coffee
module.config ($interpolateProvider)->
  $interpolateProvider.startSymbol('${')
  $interpolateProvider.endSymbol('}$')

# JavaScript version by js2coffee
#
# module.config(function($interpolateProvider) {
#   $interpolateProvider.startSymbol('${');
#   return $interpolateProvider.endSymbol('}$');
# });

## selectlang.coffee
# i18n
$rootScope._ = (key) ->
    if LANGPACK? and LANGPACK[key]?
        return LANGPACK[key]
    else
        return key

# JavaScript version by js2coffee
#
# $rootScope._ = function(key) {
#   if ((typeof LANGPACK !== "undefined" && LANGPACK !== null) && (LANGPACK[key] != null)) {
#     return LANGPACK[key];
#   } else {
#     return key;
#   }
# };

## selectlang.py
#########################################################################################
#  A middleware which sets user's locale by the query param "?lang=zh_TW" (locale name)  #
#########################################################################################

from django.utils import translation
from django.utils.translation.trans_real import get_supported_language_variant
from django.shortcuts import redirect

# for add_query_parameters
from urlparse import urlparse, parse_qsl, urlunparse
from urllib import urlencode

def add_query_parameters(url, query_parameters):
    returned_url = list(urlparse(url))
    returned_query_parms = dict(parse_qsl(returned_url[4]))

    if query_parameters:
        for qs in query_parameters:
            if query_parameters[qs] is not None:
                returned_query_parms[qs] = query_parameters[qs]
    returned_url[4] = urlencode(returned_query_parms)
    return urlunparse(returned_url)

class SelectLangMiddleware:
    '''
    Simple version for making sure all the pages have the query parameter: lang.
    You can modify it to fit your requirements.
    '''
    def process_request(self, request):

        # admin console will not be supported for i18n
        if request \
            and not str(request.path).startswith('/static') \
            and not str(request.path).startswith('/admin') \
            and not str(request.path).startswith('/api'):

            try:
                default_lang = translation.get_language()

                lang = request.GET.get("lang", None)

                if lang:
                    request.LANG = lang
                else:
                    request.LANG = default_lang
                    redirect_to = add_query_parameters(request.build_absolute_uri(), { "lang" : default_lang })
                    return redirect(redirect_to)

            except Exception as e:
                print "Error Occurred", e

## zh_TW.js
var LANGPACK = {
  "This Sentence needs to be translated.": "這一行需要被翻譯"
}
	# List of middleware classes to use. Order is important; in the request phase,
	# these middleware classes will be applied in the order given, and in the
	# response phase the middleware will be applied in reverse order.
	MIDDLEWARE_CLASSES = (
	"mezzanine.core.middleware.UpdateCacheMiddleware",
	"django.contrib.sessions.middleware.SessionMiddleware",
	"django.middleware.locale.LocaleMiddleware",

	# Add the following line into MIDDLEWARE_CLASSES
	"plusdiff.middleware.SelectLangMiddleware",

	"django.contrib.auth.middleware.AuthenticationMiddleware",
	"django.middleware.common.CommonMiddleware",
	"django.middleware.csrf.CsrfViewMiddleware",
	"django.contrib.messages.middleware.MessageMiddleware",
	"mezzanine.core.request.CurrentRequestMiddleware",
	"mezzanine.core.middleware.RedirectFallbackMiddleware",
	"mezzanine.core.middleware.TemplateForDeviceMiddleware",
	"mezzanine.core.middleware.TemplateForHostMiddleware",
	"mezzanine.core.middleware.AdminLoginInterfaceSelectorMiddleware",
	"mezzanine.core.middleware.SitePermissionMiddleware",
	# Uncomment the following if using any of the SSL settings:
	# "mezzanine.core.middleware.SSLRedirectMiddleware",
	"mezzanine.pages.middleware.PageMiddleware",
	"mezzanine.core.middleware.FetchFromCacheMiddleware",
	)
	<html>
	<head>
	<!-- Don't forget to inclue AngularJS, jQuery, etc. -->
	<script src="{% static "langpack/" %}{{ LANG }}.js"></script>
	</head>

	<body>
	${ _("This Sentence needs to be translated.") }$
	</body>

	</html>
	module.config ($interpolateProvider)->
	$interpolateProvider.startSymbol('${')
	$interpolateProvider.endSymbol('}$')

	# JavaScript version by js2coffee
	#
	# module.config(function($interpolateProvider) {
	# $interpolateProvider.startSymbol('${');
	# return $interpolateProvider.endSymbol('}$');
	# });
	# i18n
	$rootScope._ = (key) ->
	if LANGPACK? and LANGPACK[key]?
	return LANGPACK[key]
	else
	return key

	# JavaScript version by js2coffee
	#
	# $rootScope._ = function(key) {
	# if ((typeof LANGPACK !== "undefined" && LANGPACK !== null) && (LANGPACK[key] != null)) {
	# return LANGPACK[key];
	# } else {
	# return key;
	# }
	# };
	#########################################################################################
	# A middleware which sets user's locale by the query param "?lang=zh_TW" (locale name) #
	#########################################################################################

	from django.utils import translation
	from django.utils.translation.trans_real import get_supported_language_variant
	from django.shortcuts import redirect

	# for add_query_parameters
	from urlparse import urlparse, parse_qsl, urlunparse
	from urllib import urlencode

	def add_query_parameters(url, query_parameters):
	returned_url = list(urlparse(url))
	returned_query_parms = dict(parse_qsl(returned_url[4]))

	if query_parameters:
	for qs in query_parameters:
	if query_parameters[qs] is not None:
	returned_query_parms[qs] = query_parameters[qs]
	returned_url[4] = urlencode(returned_query_parms)
	return urlunparse(returned_url)

	class SelectLangMiddleware:
	'''
	Simple version for making sure all the pages have the query parameter: lang.
	You can modify it to fit your requirements.
	'''
	def process_request(self, request):

	# admin console will not be supported for i18n
	if request \
	and not str(request.path).startswith('/static') \
	and not str(request.path).startswith('/admin') \
	and not str(request.path).startswith('/api'):

	try:
	default_lang = translation.get_language()

	lang = request.GET.get("lang", None)

	if lang:
	request.LANG = lang
	else:
	request.LANG = default_lang
	redirect_to = add_query_parameters(request.build_absolute_uri(), { "lang" : default_lang })
	return redirect(redirect_to)

	except Exception as e:
	print "Error Occurred", e
	var LANGPACK = {
	"This Sentence needs to be translated.": "這一行需要被翻譯"
	}