[Zope-dev] Fw: [Zope-dev] Storing session objects in a ZODB

Wed, 31 Jan 2001 15:27:24 -0500

Cool!  Note that the session data object implements the mapping interface,
so you don't really need to pickle up a copy of it.  I'd recommend against
this, although it seems to be working well for you.

Instead, to save a session state, I'd just grab the current session data
object and iterate over its items, grabbing things out of it that are
interesting to my application.  Then I'd copy these things into another data
structure, maybe by sticking them into an instance of a class that also
implements the mapping interface and put that instance in a folder somewhere
which is related to the currently logged-in user.

Then when a user wanted to restore a saved session state, get a list of
session state objects in his session state folder, present them to him, have
him select one.  When he does, copy the items out of it into the current
session data object.

The nice thing about this general strategy is that you can work with the
current session data object in all of your app code that depends on session
state.  How the session state is saved and restored (and what the session
data object values are) is completely independent of the app code.

----- Original Message -----
From: "Andy McKay" <andym@ActiveState.com>
To: "Chris McDonough" <chrism@digicool.com>; <zope-dev@zope.org>
Sent: Wednesday, January 31, 2001 2:47 PM
Subject: Re: [Zope-dev] Fw: [Zope-dev] Storing session objects in a ZODB

> Well my quick hack and wacky of doing it is as follows:
>
> - I wrote a quick simple class "ZStore" that has as one of its properties
a
> pickle, which you can read and write to using cStringIO
> - I make a ZStore object, throw in the session object, it pickles it as
the
> data property, I add a few more useful properties, like title, owner
etc...
> - To get it back I get that object, unpickle that property and I have the
> session back.
>
> Quick hack that works for me and allows me to change the content of a
> session object, without having to change the storage. Im sure someone will
> come up with a better solution.
>
> --
>   Andy McKay.
>
>
> ----- Original Message -----
> From: "Chris McDonough" <chrism@digicool.com>
> To: <zope-dev@zope.org>
> Sent: Wednesday, January 31, 2001 11:28 AM
> Subject: [Zope-dev] Fw: [Zope-dev] Storing session objects in a ZODB
>
>
> > This is a forwarding of an interesting session-related discussion
between
> > Andy and I... it covers the idea of storing session states as
"snapshots"
> at
> > a particular time, later allowing users to select a session state.  This
> is
> > useful if you wish to allow users to make incremental changes to data in
a
> > session and "bookmark" a session state for later copying into the
current
> > session.  This is something that the "bare" session tracking stuff won't
> do
> > for you, although it can facilitate it tremendously.
> >
> > Input welcomed!
> >
> > - C
> >
> > ----- Original Message -----
> > From: "Andy McKay" <andym@ActiveState.com>
> > To: "Chris McDonough" <chrism@digicool.com>
> > Sent: Wednesday, January 31, 2001 1:56 PM
> > Subject: Re: [Zope-dev] Storing session objects in a ZODB
> >
> >
> > > > I think you may be trying to use sessions to do something that
> sessions
> > > > don't do.  You can *use* the sessioning machinery as a base to build
> the
> > > > infrastructure to do such a thing, but it won't do it out of the
box.
> I
> > > am
> > > > currently trying to build an "onSessionStart" and "onSessionEnd"
event
> > > into
> > > > session data objects.  If you had this capability, an arbitrary
Python
> > > > method (or DTML method or external method) could be called when a
> > session
> > > > data object is created and when it expires.  If you were to make use
> of
> > > > these hooks to copy the state of the session data object into
another
> > > > structure (related to the currently logged in user - a "checkpoint"
if
> > you
> > > > will), you could build a catalog of session states that could be
> > recopied
> > > > into the current session namespace.
> > > >
> > > > Alternately, you could forego the use of events and just have a
button
> > > that
> > > > says "save session state" somewhere, and copy the contents of the
> > session
> > > > namespace into something else.  Then when a user wanted to choose a
> > > session
> > > > state, copy it back into the current session namespace.  This is the
> > same
> > > > idea, it just lets the user be explicit about what session state he
> > wants
> > > to
> > > > use instead of depending on the event hook to create a new state.
> > >
> > > Bingo, yes that's it!
> > >
> > > > Does this make sense?  Can I cc this to Zope-Dev so we can get some
> > > > discussion about it?
> > >
> > > Absolutely!
> > >
> > > --
> > >   Andy McKay.
> > >
> > > >
> > > >
> > > > > ----- Original Message -----
> > > > > From: "Chris McDonough" <chrism@digicool.com>
> > > > > To: "Andy McKay" <andym@ActiveState.com>
> > > > > Sent: Tuesday, January 30, 2001 9:53 AM
> > > > > Subject: Re: [Zope-dev] Storing session objects in a ZODB
> > > > >
> > > > >
> > > > > > Andy,
> > > > > >
> > > > > > I'm still not sure why you wouldn't set up an external data
> > > container..
> > > > if
> > > > > > you want, you can call me at 540-371-6909 if you think you can
> > explain
> > > > it
> > > > > > better over the phone...
> > > > > >
> > > > > > - C
> > > > > >
> > > > > >
> > > > > >
> > > > > > ----- Original Message -----
> > > > > > From: "Andy McKay" <andym@ActiveState.com>
> > > > > > To: "Chris McDonough" <chrism@digicool.com>
> > > > > > Sent: Tuesday, January 30, 2001 12:28 PM
> > > > > > Subject: Re: [Zope-dev] Storing session objects in a ZODB
> > > > > >
> > > > > >
> > > > > > > Well each user rummages through a site and saves preferences,
I
> > use
> > > > > these
> > > > > > > preferences for displaying things in a certain manner,
> generating
> > > SQL
> > > > > etc.
> > > > > > > Since some of these SQL statements get quite complex, it would
> be
> > > nice
> > > > > to
> > > > > > be
> > > > > > > to able to pull saved session x which has a query that "looks
up
> > by
> > > x
> > > > by
> > > > > y
> > > > > > > excluding z" etc...
> > > > > > >
> > > > > > > So anyway I like using the ZODB for this kind of storage since
> > it's
> > > of
> > > > > low
> > > > > > > volume and a large amount of reads and the users want to use
> > > > acquisition
> > > > > > to
> > > > > > > the full (we have a wacky hierarchy). If I could pull that
into
> a
> > > text
> > > > > > area
> > > > > > > to allow level editing then that would be an added bonus...
> > > > > > >
> > > > > > > Did that make sense?
> > > > > > > --
> > > > > > >   Andy McKay.
> > > > > > >
> > > > > > >
> > > > > > > ----- Original Message -----
> > > > > > > From: "Chris McDonough" <chrism@digicool.com>
> > > > > > > To: "Andy McKay" <andym@ActiveState.com>
> > > > > > > Sent: Monday, January 29, 2001 5:49 PM
> > > > > > > Subject: Re: [Zope-dev] Storing session objects in a ZODB
> > > > > > >
> > > > > > >
> > > > > > > > > Sure but users want to be able acess and manipulate the
> stored
> > > > > session
> > > > > > > > > objects, without them being loaded... Im going for a bike
> ride
> > > to
> > > > > > think
> > > > > > > > > about this one.
> > > > > > > >
> > > > > > > > Erm.  What?  :-)  Can you give me an example?
> > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > >
> > >
> > >
> >
> >
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