#__init__.py

from flash.util import error, notice, error_next, notice_next


#exception.py

# -*- coding: utf-8

class RedirectException(Exception):
    def __init__(self,redirect_uri,*args,**kwargs):
        try:
            self.error_message = kwargs['error']
            del kwargs['error_message']
        except KeyError:
            self.error_message = None
        try:
            self.notice_message = kwargs['notice']
            del kwargs['notice_message']
        except KeyError:
            self.notice_message = None
        self.redirect_uri = redirect_uri

        Exception.__init__(self,*args,**kwargs)



#middleware.py

from django.http import HttpResponse, HttpResponseRedirect

from flash.exception import RedirectException

class FlashMiddleware(object):
    def process_request(self, request):
        from util import data
        data.session = request.session

        old_flash = request.session.get('flash', None).copy()
        try:
            next_messages = request.session['flash']['next_messages'].copy()
            print 'NEXT:', next_messages
        except KeyError:
            next_messages = {'errors':[],'notices':[]}
        request.session.setdefault('flash', {})['next_messages'] = {
            'errors': [], 'notices': []}
        request.session['flash']['messages'] = next_messages

        if old_flash != request.session['flash']:
            request.session.modified = True


    def process_exception(self, request, exception):
        if isinstance(exception,RedirectException):
            if exception.error_message:
                request.session['flash']['next_messages']['errors'].append(
                    exception.error_message)
            if exception.notice_message:
                request.session['flash']['next_messages']['notices'].append(
                    exception.notice_message)
            return HttpResponseRedirect(exception.redirect_uri)



#util.py

from threading import local

data = local()

def error(msg):
    data.session['flash']['messages']['errors'].append(msg)
    data.session.modified = True


def error_next(msg):
    data.session['flash']['next_messages']['errors'].append(msg)
    data.session.modified = True


def notice(msg):
    data.session['flash']['messages']['notices'].append(msg)
    data.session.modified = True


def notice_next(msg):
    data.session['flash']['next_messages']['notices'].append(msg)
    data.session.modified = True



#templatetags/flash_extras.py

# -*- coding: utf-8
from django import template

register = template.Library()

@register.inclusion_tag('flash/messages.html', takes_context=True)
def flash(context):
    return {'errors': context['request'].session['flash']['messages']['errors'],
            'notices': context['request'].session['flash']['messages']['notices']}


#templates/flash/messages.html

{% if errors or notices %}
    <div class="flash-messages">
    {% if errors %}
        <ul class="errors">
    {% for error in errors %}
            <li>{{ error|safe }}</li>
    {% endfor %}
        </ul>
    {% endif %}
    {% if notices %}
        <ul class="notices">
    {% for notice in notices %}
            <li>{{ notice|safe }}</li>
    {% endfor %}
        </ul>
    {% endif %}
    </div>
{% endif %}