Check for session attributes through EL

[vk101]

If I want to see whether there's a user component in session scope, how in EL can I output the presence of a component in the session context?

I tried the following but it gives an error saying the "user" property is not found:

#{not empty sessionContext.user}
#{not empty sessionContext['user']}

I simply tried #{not empty user} but this always equals true (i.e. there is a user component existing somewhere) even though I don't know how the component is existing on the first access of the page. The JSF pages don't refer to any of the properties of "user" so it shouldn't be getting automatically instantiated...

What's the proper way to check through EL if something's been added to session scope?

[norman.richards]

I don't think this is possible. You could probably write a component to do this, but I think I'd go with a facelets EL function.

[norman.richards]

I don't think this is possible. You could probably write a component to do this, but I think I'd go with a facelets EL function.

[vk101]

So how would you conditionally render a component based on whether a user is logged in or not (e.g. the user component has been added to session scope)?

Also, is adding a user component to session scope and checking if it exists there the best way to check whether a user is logged in?

[ssilvert]

Just for kicks, have you tried this?

#{not empty sessionScope.user}

"sessionScope" comes from JSF core.

Stan

[vk101]

Yes that works, thank you. Now how would you do the same thing but for checking Seam-specific contexts such as conversation and business process? Does this functionality really not exist?

[perwik]

I'd rather use something like

rendered="#{userSession.authenticated}"

where userSession is some bean that knows if the user is authenticated. This is also decouples the required logic from the view.

[ssilvert]

"lightbulb432" wrote:
Yes that works, thank you. Now how would you do the same thing but for checking Seam-specific contexts such as conversation and business process? Does this functionality really not exist?

I haven't actually tried it, but I'll take your word for it that it doesn't work.

I agree with perwik that his solution is better. However, I also think that if possible, Seam-specific contexts should be made to work. I'd file a Jira task on it with some sample code. Then see what Gavin thinks.

Stan