Restrict User to Single Login

Greetings,

- Goal -

Restrict users from login on two computers at same time.

I have indicated below the code that is suppose to check for and terminate

a session if user has logged in twice. If I remove the code, the authentication

process functions as expected, but allows for mutlipe logins.

I am attempting to follow the tutorial example: http://tutorial452.easycfm.com

for my solution and am not having any luck. When I attempt to run the process

I get the following error message.

"Element USER_ID is undefined in THISSESSION"

If I run the code below on a page, it returns a list of current sessions,

associated with the login process.

<cfset tracker = createObject("java","coldfusion.runtime.SessionTracker")>
<cfset sessions = tracker.getSessionCollection(application.applicationName)>
<cfdump var="#sessions#">

Obviously I am missing something here. If there is a better way to accomplish

my goal, I am certainly open to suggestions.

Leonard B

<=== My Code ===>

<cfquery name="rs_verify" datasource="[dsn]">
    SELECT
        user_id,
        first_name,
        last_name,
        login,
        password
    FROM
        login_once
    WHERE
        login = <cfqueryparam value="#login#" cfsqltype="cf_sql_varchar"> AND
        password = <cfqueryparam value="#password#" cfsqltype="cf_sql_varchar">
</cfquery>

<!--- == Checks and logs out user if logged in twice ========== --->

<!--- If code below is removed login process works without issues --->

<cfif rs_verify.recordCount>

    <cfset tracker = createObject("java","coldfusion.runtime.SessionTracker")>
    <cfset sessions = tracker.getSessionCollection(application.applicationName)>

    <cfloop item="loopSession" collection="#sessions#">
    <cfscript>
        thisSession = sessions[loopSession];
        thisUser = thisSession.user_id;
        if(thisUser EQ rs_verify.user_id){
            thisSession.setMaxInactiveInterval(1);
            break;       
        }   
    </cfscript>
    </cfloop>

    <!--- log them in --->

    <cfset session.user_id = rs_verify.user_id>

</cfif>

<!--- If code above is removed login process works without issues --->

<!--- ============================================ --->

<cfset comparison = Compare(form.password, rs_verify.password)>

<!--- Start Tag --->
<!--- Verification that a record match exits --->
<cfif rs_verify.RecordCount>

<!--- Password case sensitive comparison --->
<cfif comparison eq 0>

<!--- Set session variables for later use --->
<cfset session.allowin = "True">
<cfset session.first_name = "#rs_verify.first_name#">
<cfset session.last_name = "#rs_verify.last_name#">
<cfset session.login = "#rs_verify.login#">
<cfset session.password = "#rs_verify.password#">
<!--- Set session variables for later use --->

<!--- Section relocation to appropriate page --->
<cflocation url="index.cfm" addtoken="no">
<!--- Section relocation to appropriate page --->

<!----------------------------------------------------------------------------->
<cfelse><!---  Case sensitive comparison - mismatch --->
<!----------------------------------------------------------------------------->
           
<!--- Section displaying password case sensitive mismatch--->
<cfinclude template="insert_password_mismatch.cfm">
<!--- Section displaying password case sensitive mismatch--->

</cfif>
<!--- Password case sensitive comparison --->

<!---------------------------------------------------------------------->
<cfelse><!---  No record found statement portion --->
<!---------------------------------------------------------------------->
           
<!--- Section displaying no record found information --->
<cfinclude template="insert_no_record_found.cfm">
<!--- Section displaying no record found information --->

</cfif>
<!--- Verification that a record match exits --->