Clear session variable without ending session?

[kingcarol]

I use a lot of session variables to filter data in components that are opened from another component. I worry that this may bog down the browser by taking up its memory. I would like to know if that is true. And, if so, is there a way to clear out the session variables used to filter a component when that filtered component is closed, WITHOUT ending the user's session? Thank you.

[GGandhi]

Re: Clear session variable without ending session?

https://www.alphasoftware.com/docume...e%20Method.xml

does this help?

[kingcarol]

Re: Clear session variable without ending session?

That looks promising. Leaving on trip and won't be able to try until Monday. Wonder if I need to use that function in an xbasic callback?

[GGandhi]

Re: Clear session variable without ending session?

it is an xbasic function, so i would imagine that is the way to do. since the sessions are in the server, xbasic will set it the way you want it. setting and removing.

[kingcarol]

Re: Clear session variable without ending session?

I wonder if too many session variables can affect browser speed and performance? If so, then I will pursue trying to get them removed when no longer needed (using the method you suggest).

[Davidk]

Re: Clear session variable without ending session?

Sorry... have to ask... Gandhi... did you test what you posted?

Establishing a Session Variable in, for example, the onDialogInitialize event of a UX...

session.mytest1 = "sessionTest1"
session.mytest2 = "sessionTest2"

And then setting up 2 XBasic functions, each being called from a button on the UX...

{dialog.Object}.ajaxCallback('','','removeSessionVars','');
{dialog.Object}.ajaxCallback('','','testSessionVars','');

function removeSessionVars as c (e as p)
	
debug(1)

Context.Session.Remove(session.mytest1)
delete session.mytest2
	
end function

function testSessionVars as c (e as p)

debug(1)

dim s1 as c
dim s2 as c

s1 = session.mytest1
s2 = session.mytest2
	
end function

The result is that s1 is set with the value of session.mytest1. session.mytest1 is still a valid session variable.
s2 results in an error because session.mytest2 has been deleted.

Carol, I believe what you're looking for is delete.

Gandhi, try the above and see if you get the same or different results.

[Davidk]

Re: Clear session variable without ending session?

I wonder if too many session variables can affect browser speed and performance? If so, then I will pursue trying to get them removed when no longer needed (using the method you suggest).

I'd guess you'd have to quantify "too many". 1,000? 10,000? 50?

[Lenny Forziati]

Re: Clear session variable without ending session?

David, you have an error in your Xbasic. The parameter passed into the Remove method should be the name of the variable to remove, not the variable itself.

Context.Session.Remove(session.mytest1)

should be

Context.Session.Remove("mytest1")

When used correctly, Context.Session.Remove() and delete are equivalent.

[Davidk]

Re: Clear session variable without ending session?

Excellent... thanks Lenny...

[kingcarol]

Re: Clear session variable without ending session?

I'd guess you'd have to quantify "too many". 1,000? 10,000? 50?

I can only guess, but probably at least 1,000. But, in general, I want to know if session variables can affect performance at all?

[kingcarol]

Re: Clear session variable without ending session?

Thank you, Lenny, David, and Gandhi. I'll try it Monday. In general, Is it a good practice to remove session variables when component filtered to them is closed, and they are no longer needed?

[RichCPT]

Re: Clear session variable without ending session?

Carol, if you are going to the conference, perhaps you could ask Selwyn and the rest of the developers how to program without using Session variables to pass data around from one component to the next at both the client (JavaScript) and server (xbasic) level. I posted the following sample application several years ago. I bet the AA engineers could redo this using better code and/or see where they could build in some more routines to help in this matter. This demonstrates most of the different situations where parameter passing needs to be done (and can be done) without sessions vars:

https://www.alphasoftware.com/alphaf...d-Lookup-Grids

If your app uses a tabbedUI then session variables may get fowled up between different instances of a component being opened in different tabs. I admit there are still places in my code where I use session variables (whose values change after login, based on selected record), and at some point I will eliminate them. For anything new I write, I avoid changing the value of session variables after the user has made it through the login process. After I know who is signing into the app, I asked them what dataset they want to use (which sets several session variables), and if they have multiple roles in the selected dataset, I ask them what user role (my "role" definition; not an AA Security Role) they want to use for that session (which sets a few more sessions vars).

I also, really worry about Alpha Session variables when it comes to a user opening the web app in two different instances of the browser or in two different browser tabs.
For example, when the user tries to go to my login page in another tab, I have the following in the xbasic code block at the top of the a5w page:

if variable_exists("session.SOME_VARIABLE")
	response.redirect("ERR_MULTI_SESSIOINS_NOT_ALLOWED.a5w")
	end
end if

When the user clicks "Logout" link, I direct them to an a5w page that records the exit date/time in the DB and then clears out the session vars with this bit of code:

A5WS_LogoutUser( )
Context.Response.Clear()  '** Not sure if this is necessary, maybe it is something for IIS
session.clear()	 '** This is required to clear the session variables.

If a new browser tab can "see" the session variables from a different browser tab then it proves to me that you cannot rely on the session variables to always have the expected value. If you can copy the session variable value to a local variable for that component when the component is first opened and always use the copied value then you might be okay. But then there is the big problem about knowing if a cached version (cached from different browser tab) of the component was used instead of reloading it from the server. I turn all component caching off, but what if I miss doing that for some component or if in the AA builders you run across a place where that option is not available?

P.S. 1,000 session vars is an awful lot. How do you even manage giving them unique names? If you are looking at performance issues, I would look at client-side conditional formatting - they can add a whole lot of processing time. I have a component that cannot be run on Safari because the client-side conditionals take so much time to execute on Safari. I think the alternative is to go with client-side templating and local CSS classes such that the data includes something to do with what CSS class name should be added to an element. Also, another, not so drastic measure, is to have your own JavaScript code set and remove CSS classes from elements.

-Rich Fulham

[GGandhi]

Re: Clear session variable without ending session?

Sorry... have to ask... Gandhi... did you test what you posted?

Establishing a Session Variable in, for example, the onDialogInitialize event of a UX...

session.mytest1 = "sessionTest1"
session.mytest2 = "sessionTest2"

And then setting up 2 XBasic functions, each being called from a button on the UX...

{dialog.Object}.ajaxCallback('','','removeSessionVars','');
{dialog.Object}.ajaxCallback('','','testSessionVars','');

function removeSessionVars as c (e as p)
	
debug(1)

Context.Session.Remove(session.mytest1)
delete session.mytest2
	
end function

function testSessionVars as c (e as p)

debug(1)

dim s1 as c
dim s2 as c

s1 = session.mytest1
s2 = session.mytest2
	
end function

The result is that s1 is set with the value of session.mytest1. session.mytest1 is still a valid session variable.
s2 results in an error because session.mytest2 has been deleted.

Carol, I believe what you're looking for is delete.

Gandhi, try the above and see if you get the same or different results.

So you are all set david?
Sorry have to ask make sure you are okay.