'CSRF Verification Failed' in Django Translation

[Veni Kunche]

Hi everyone,

I've set up translation for a Django app using this tutorial. I am using Python 3.4.5 and Django 1.9.10.  I used set_language to switch between the languages. Everything was working great locally. However, I get a "CSRF Verification Failed" error on our test server sometimes. I've tried the common suggestions that I've found online:

• I verified that {% csrf_token %} is inside the form
• I checked that 'django.middleware.locale.LocaleMiddleware' has been added
• I do have url(r'^i18n/', include('django.conf.urls.i18n')), in urls.py

These are the settings that are different in the test environment:

CSRF_COOKIE_SECURE = True
SESSION_COOKIE_SECURE = True
SESSION_COOKIE_HTTPONLY = True
SECURE_CONTENT_TYPE_NOSNIFF = True
CSRF_COOKIE_HTTPONLY = True
SECURE_BROWSER_XSS_FILTER = True
X_FRAME_OPTIONS = 'DENY'
CORS_ORIGIN_ALLOW_ALL = True

The test environment is running on https. The application has other forms which do posts and those are working fine. It's only the set_language form that's causing the error.

My questions:

1. Is there anything else that I should look into?
2. Is there another way to switch the language besides set_language in a form like this?

   <form action="{% url 'set_language' %}" method="post">
       {% csrf_token %}
       <input name="next" type="hidden" value="{{ redirect_to }}" />
       <select name="language">
           {% get_current_language as LANGUAGE_CODE %}
           {% get_available_languages as LANGUAGES %}
           {% for lang in LANGUAGES %}
               <option value="{{ lang.0 }}" {% if lang.0 == LANGUAGE_CODE %} selected="selected"{% endif %}>
                   {{ lang.1 }} ({{ lang.0 }})
               </option>
           {% endfor %}
       </select>
       <input type="submit" value="Go" />
   </form>

Thank you for your help! Let me know if I can clarify further.

-Veni