Re: [Cgi-session-user] writing CGI::Session sessions only when necessary

[Jonathan S. <sw...@po...>]

On Jan 27, 2010, at 6:41 AM, Mark Stosberg wrote:

> On Tue, 26 Jan 2010 16:42:38 -0800
> Jonathan Swartz <SW...@PO...> wrote:
>
>> On our site we create a new CGI::Session object at the beginning of
>> the request, so that it can be used anywhere in the web code.
>>
>> However, sessions are rarely written to, so at the end of the request
>> I'd like to avoid actually writing out a new session to backing store
>> unless a param actually got set. The expense of writing out new
>> sessions, and cleaning them up later, has become significant.
>
> Jon,
>
> For a model of how to do this, see CGI::Application::Plugin::Session.
> I think you'll find the concepts there portable to your own code.
> Here's the overview:
>
> session_config() collects the necessary config details, but doesn't do
> anything with them. This runs on every request and just takes a  
> momeent.
>
> session() lazy-loads a CGI::Session object using the details collected
> in session_config(). That is to say, the session is not loaded until  
> you
> call a method on CGI::Session somewhere in your code like:
>
> $self->session->param('foo');
>
> Many CGI::Application plugins are designed this way, often deferring
> loading even the helper modules themselves. This is one of the design
> principles that helps CGI::Application projects run well under CGI,
> because in a sense you only pay for what you use.
>

Thanks Mark. I thought of this idea too. But will this end up creating  
a session if someone simply *reads* a session parameter? I'd like to  
only create the session if someone actually *writes* a session  
parameter. The latter will occur far less often.