[Seaside] Accessing current session in RestfulFilter

[Philippe Marschall]

On Wed, May 28, 2014 at 1:40 PM, Esteban Lorenzano <estebanlm at gmail.com> wrote:
> Hi,
>
> AFAIK, REST purpose is to be stateless, and because of that you do not have the session available when passing through the filter.
> Nevertheless, I hacked the REST filter to use it as an bookmarked entry point for my applications (to provide readable urls). What I did is to add this:
>
> (notice that is kind of a hack… probably there is a better way to do this).
>
> MyRestFilter>>#continueWithRoot: aBlock
>         "Continues the execution of the application.
>          I will execute aBlock with the root component of app"
>         | requestContext application session rootComponent |
>
>         requestContext := self requestContext.
>         application := requestContext application.
>         session := self obtainSessionWithApplication: application context: requestContext.
>
>         requestContext
>                 push: session
>                 during: [
>                         rootComponent := requestContext rootComponentIfAbsent: [ nil ].
>                         rootComponent ifNil: [
>                                 rootComponent := (application preferenceAt: #rootClass) new.
>                                 requestContext rootComponent: rootComponent ].
>                         aBlock value: rootComponent.
>                         self next handleFiltered: requestContext ].
>
> MyRestFilter>>#obtainSessionWithApplication: application context: requestContext
>         | sessionKey session |
>
>         sessionKey  := application trackingStrategy keyFromContext: requestContext.
>         session := sessionKey ifNotNil: [
>                 application cache
>                         at: sessionKey
>                         ifAbsent: [ nil] ].
>
>         session  ifNil: [
>                 session := application newSession.
>                 application register: session ].
>
>         ^ session
>
> with that, I can add some filters like this:
>
> MyRestFilter>>#newScan
>         <get>
>         <path: '/new'>
>
>         self continueWithRoot: [ :root |
>                 root show: EveSpyNewTrackPanel new ].
>
> If I understand what I’m doing, this will:
>
> a) look for an active session
> a.1) retrieve a new one if not found
> b) obtain the root component for active session
> c) use #show:, to display the component I want to display.
>
> It works… I don’t know if it can be done better… but that’s how I provide readable urls to my apps usually :)

Here's what you should do:
- subclass WARestfulComponentFilter
- add it to your application
- implement the methods for the URL patterns you need
- send #startSessionWithRoot: in your methods

Cheers
Philippe