bottle-flash2 - Fixed up abandoned bottle-flash[https://pypi.python.org/pypi/bottle-flash/]. Made api ver 2 ready. Plugin enables flash messages in bottle similar to django and flask.

bottle_flash2.py

from bottle import request, response, PluginError

class FlashMsgPlugin(object):
    """Usage:
    from bottle import Bottle
    from bottle_flash2 import FlashMsgPlugin
    
    app = Bottle()
    COOKIE_SECRET = 'your_secret_key'
    app.install(FlashPlugin(secret=COOKIE_SECRET))
    
    @route('/logout', name='logout')
    def logout():
        app.flash('Logged out successfully !')
        redirect(url('login'))
    
    . To consume the flashed messages, 
    . you would do something like the following (jinja2).
    . Here I am assuming that I get the "app" in the template context.
    
    {% set messages = app.get_flashed_messages() %}
    {% if messages %}
    <div id="flash_messages">
      <ul>
          {% for m in messages %}
          <li>{{ m[0] }}</li>
          {% endfor %}
      </ul>
    </div>
    {% endif %}
    
    . This can be achieved with the bottle_renderer_ plugin,
    . or by adding to the defaults dict like this..
    
    Jinja2Template.defaults = {'app': app}
    
    . placing the app in all template contexts.
    
    """
    name = 'flash'
    api = 2

    def __init__(self, key=name, secret=None):
        self.key = key
        self.app = None
        self.secret = secret

    def setup(self, app):
        """ Make sure that other installed plugins don't affect the same
        keyword argument and check if metadata is available."""
        for other in app.plugins:
            if not isinstance(other, FlashMsgPlugin):
                continue
            if other.keyword == self.keyword:
                raise PluginError("Found another flashmsg plugin "
                                          "with conflicting settings ("
                                          "non-unique keyword).")
        self.app = app
        self.app.add_hook('before_request', self.load_flashed)
        self.app.add_hook('after_request', self.set_flashed)
        self.app.flash = self.flash
        self.app.get_flashed_messages = self.get_flashed_messages

    def load_flashed(self):
        m = request.get_cookie(self.key, secret=self.secret)
        if m is not None:
            response.flash_messages = m

    def set_flashed(self):
        if hasattr(response, 'flash_messages'):
            return response.set_cookie(self.key,
                                       response.flash_messages,
                                       self.secret)

    def flash(self, message, level=None):
        if not hasattr(response, 'flash_messages'):
            response.flash_messages = []
        response.flash_messages.append((message, level))

    def get_flashed_messages(self):
        if hasattr(response, 'flash_messages'):
            m = response.flash_messages
            response.delete_cookie(self.key)
            delattr(response, 'flash_messages')
            return m

    def apply(self, callback, context):
        return callback
        

"""
The MIT License (MIT)

Copyright (c) 2014

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"""

Hi, thanks for getting this working.
Just a quick note, at line 10 replace FlashPlugin with FlashMsgPlugin.