On Mon, Apr 29, 2013 at 10:13 AM, David Marko <[email protected]> wrote:
> Is there a way how to use/crrate a viewScope on conversationScope like
> variable in web2py? In JAVA based frameworks (e.g. JSF, Spring Framework)
> there are scoped environments available. In web2py we have requestScope, and
> sessionScope (if I use this naming) but cant figure out how to create a
> viewSope(or conversationScope) which is like session but bound to one
> page(its instance.) only. So when user submits page without redirect the
> viewScope variable is still available. This is very nice scenario e.g. how
> to create nice wizards within a one page as viewScope holds position
> 'securely' . And there are other use casesas well. (btw. applicationScope
> would be very ncie as well but I know we can use cache here, but these scope
> are more transparent).
>
You can implement yourself using sessions.
If I understood correctly, a quick implementation could look like
this, in a model:
scope_key = '/%s/%s/%s' % (request.application, request.controller,
request.function)
if session.page_scope is None:
session.page_scope = Storage()
if session.page_scope[scope_key] is None:
session.page_scope[scope_key] = Storage()
myscope = session.page_scope[scope_key]
Then use myscope.var instead of session.var
A more abstract way could be creating some helper classes, something like:
from gluon.globals import current
from gluon.storage import Storage
SCOPE_ROOT = 'scopes'
class Scope(dict):
__slots__ = ()
def __init__(self, namespace):
session = current.session
if not session[SCOPE_ROOT]:
session[SCOPE_ROOT] = Storage()
if not session[SCOPE_ROOT][namespace]:
session[SCOPE_ROOT][namespace] = Storage()
self['_namespace'] = namespace
@property
def namespace(self):
return self['_namespace']
def __getattr__(self, key):
return current.session[SCOPE_ROOT][self.namespace][key]
def __setattr__(self, key, value):
current.session[SCOPE_ROOT][self.namespace][key] = value
def __delattr__(self, key):
try:
del current.session[SCOPE_ROOT][self.namespace][key]
except KeyError:
pass
class PageScope(Scope):
__slots__ = ()
def __init__(self):
request = current.request
namespace = '/%s/%s/%s' % (request.application,
request.controller,
request.function)
super(PageScope, self).__init__(namespace)
save it in a module and then you can use it in controllers:
from myscope_module import Scope, PageScope
def index():
wiz = Scope('wizard_multi_page')
wiz.var1 = 'var1'
wiz.var2 = 'var2'
wiz2 = PageScope()
wiz2.var1 = 'var1'
wiz2.var2 = 'var2'
def index2():
wiz = Scope('wizard_multi_page')
wiz.var1 = 'var1'
wiz.var2 = 'var2'
wiz2 = PageScope()
wiz2.var1 = 'var3'
wiz2.var2 = 'var4'
Session data structure will be something like:
Session items
+---- scopes
+---- wizard_multi_page
| +--- var1 = 'var1'
| +--- var2 = 'var2'
+---- /app/default/index
| +---- var1 = 'var1'
| +---- var2 = 'var2'
+---- /app/default/index2
+---- var1 = 'var3'
+---- var2 = 'var4'
I think it is closed to what you want, at least the PageScope, isn't it?
Note: I did a quick test, only with session in file, and seems to work.
Ricardo
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