Custom AJAX storage for Django's messages framework

settings.py

MESSAGE_STORAGE = 'PROJECT_NAME.storage.CustomAjaxStorage'

storage.py

# Pass messages to client in AJAX response
# _is_ajax check relies on X-Requested-With: XMLHttpRequest header

import json

from django.contrib.messages.storage.fallback import FallbackStorage

class CustomAjaxStorage(FallbackStorage):
    """
    If request is AJAX add messages to response content.
    Otherwise pass to FallbackStorage
    """

    def _is_ajax(self, request):
        if request.headers.get('x-requested-with') == 'XMLHttpRequest':
            return True
        else:
            return False

    def _store(self, messages, response, *args, **kwargs):
        if self._is_ajax(self.request):
            if response.content:
                response_content = json.loads(response.content)
            else:
                response_content = {}
            response_content['messages'] = []
            for message in messages:
                response_content['messages'].append({
                    'message': message.message,
                    'tags': message.tags
                    })
            response.content = json.dumps(response_content)
        else:
            return super(CustomAjaxStorage, self)._store(messages, response, *args, **kwargs)