i18n: added get_available_languages tag and added a default view for switching languages (both from the django-dev posting of jacob)

git-svn-id: http://code.djangoproject.com/svn/django/branches/i18n@1048 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/conf/urls/i18n.py

@@ -0,0 +1,5 @@
+from django.conf.urls.defaults import *
+
+urlpatterns = patterns('',
+    (r'^setlang/$', 'django.views.i18n.set_language'),
+)

django/core/template/defaulttags.py

@@ -290,6 +290,16 @@ class WidthRatioNode(Node):
             return ''
         return str(int(round(ratio)))
 
+class GetAvailableLanguagesNode(Node):
+
+    def __init__(self, variable):
+        self.variable = variable
+
+    def render(self, context):
+        from django.conf.settings import LANGUAGES
+        context[self.variable] = LANGUAGES
+        return ''
+
 class I18NNode(Node):
 
     def __init__(self, cmd):
@@ -803,6 +813,28 @@ def do_widthratio(parser, token):
         raise TemplateSyntaxError("widthratio final argument must be an integer")
     return WidthRatioNode(this_value_var, max_value_var, max_width)
 
+def do_get_available_languages(parser, token):
+    """
+    This will store a list of available languages
+    in the context.
+
+    Usage is as follows::
+
+        {% get_available_languages as languages %}
+        {% for language in languages %}
+        ...
+        {% endfor %}
+
+    This will just pull the LANGUAGES setting from
+    your setting file (or the default settings) and
+    put it into the named variable.
+    """
+
+    args = token.contents.split()
+    if len(args) != 3 or args[1] != 'as':
+        raise template.TemplateSyntaxError("'get_available_languages' requires 'as variable' (got %r)" % args)
+    return GetAvailableLanguagesNode(args[2])
+
 def do_i18n(parser, token):
     """
     translate a given string with the current
@@ -837,3 +869,4 @@ register_tag('now', do_now)
 register_tag('templatetag', do_templatetag)
 register_tag('widthratio', do_widthratio)
 register_tag('i18n', do_i18n)
+register_tag('get_available_languages', do_get_available_languages)

django/utils/translation.py

@@ -274,6 +274,19 @@ def ngettext(singular, plural, number):
 gettext_lazy = lazy(gettext, str)
 ngettext_lazy = lazy(ngettext, str)
 
+def check_for_language(lang_code):
+    """
+    This function checks wether there is a global language
+    file for the given language code. This is used to decide
+    wether a user-provided language is available.
+    """
+    from django.conf import settings
+    globalpath = os.path.join(os.path.dirname(settings.__file__), 'locale')
+    if gettext_module.find('django', globalpath, [to_locale(lang_code)]) is not None:
+        return True
+    else:
+        return False
+
 def get_language_from_request(request):
     """
     analyze the request to find what language the user
@@ -284,29 +297,14 @@ def get_language_from_request(request):
     from django.conf import settings
     globalpath = os.path.join(os.path.dirname(settings.__file__), 'locale')
 
-    if request.GET or request.POST:
-        lang_code = request.GET.get('django_language', None) or request.POST.get('django_language', None)
-        if lang_code is not None:
-            lang = gettext_module.find('django', globalpath, [to_locale(lang_code)])
-            if lang is not None:
-                if hasattr(request, 'session'):
-                    request.session['django_language'] = lang_code
-                else:
-                    request.set_cookie('django_language', lang_code)
-                return lang_code
-
     if hasattr(request, 'session'):
         lang_code = request.session.get('django_language', None)
-        if lang_code is not None:
-            lang = gettext_module.find('django', globalpath, [to_locale(lang_code)])
-            if lang is not None:
-                return lang_code
+        if lang_code is not None and check_for_language(lang_code):
+            return lang_code
     
     lang_code = request.COOKIES.get('django_language', None)
-    if lang_code is not None:
-        lang = gettext_module.find('django', globalpath, [to_locale(lang_code)])
-        if lang is not None:
-            return lang_code
+    if lang_code is not None and check_for_language(lang_code):
+        return lang_code
     
     accept = request.META.get('HTTP_ACCEPT_LANGUAGE', None)
     if accept is not None:

django/views/i18n.py

@@ -0,0 +1,22 @@
+from django.utils import httpwrappers
+from django.utils.translation import check_for_language
+
+def set_language(request):
+    """
+    Redirect to a given url while setting the chosen language in the
+    session or cookie. The url and the language code need to be
+    specified in the GET paramters.
+    """
+    lang_code = request.GET['language']
+    next = request.GET.get('next', None)
+    if not next:
+        next = request.META.get('HTTP_REFERER', None)
+    if not next:
+        next = '/'
+    response = httpwrappers.HttpResponseRedirect(next)
+    if check_for_language(lang_code):
+        if hasattr(request, 'session'):
+            request.session['django_language'] = lang_code
+        else:
+            response.set_cookie('django_language', lang_code)
+    return response