"""Helpers for the Pylons web framework
These helpers depend on Pylons' ``request``, ``response``, ``session``
objects or some other aspect of Pylons. Most of them can be easily ported to
another framework by changing the API calls.
"""
# Do not import Pylons at module level; only within functions. All WebHelpers
# modules should be importable on any Python system for the standard
# regression tests.
class Flash(object):
"""Accumulate a list of messages to show at the next page request.
This class is useful when you want to redirect to another page and also
show a status message on that page, such as "Changes saved" or
"No previous search found; returning to home page".
THIS IMPLEMENTATION DEPENDS ON PYLONS. However, it can easily be adapted
for another web framework.
Normally you instantiate a Flash object in myapp/lib/helpers.py::
from webhelpers.pylonslib import Flash as _Flash
flash = _Flash()
The helpers module is then imported into your controllers and
templates as `h`. Whenever you want to set a message, do this::
h.flash("Record deleted.")
You can set additional messages too::
h.flash("Hope you didn't need it.")
Now make a place in your site template for the messages. In Mako you
might do:
.. code-block:: mako
<% messages = h.flash.pop_messages() %>
% if messages:
% for message in messages:
- ${message}
% endfor
% endif
You can style this to look however you want:
.. code-block:: css
ul#flash-messages {
color: red;
background-color: #FFFFCC;
font-size: larger;
font-style: italic;
margin-left: 40px;
padding: 4px;
list-style: none;
}
"""
def __init__(self, session_key="flash"):
self.session_key = session_key
def __call__(self, message):
from pylons import session
session.setdefault(self.session_key, []).append(message)
session.save()
def pop_messages(self):
from pylons import session
messages = session.pop(self.session_key, [])
session.save()
return messages