To create a session explicitly for first the first time page loads in Grails - session

Question

As soon as a page loads, it renders a lot of data and shows on the view which sort of slows down the performance. I want to restrict this and load the data only when a filter is applied .
I need a way in which a session variable can store the value on the 1st login and no data should be loaded in that 1st session i.e. when any user loads it for the very first time using his login. something like the below in the controller class:
if(session.dtstartDate && session.dtstartDate != '')
{
SimpleDateFormat nsdf = new SimpleDateFormat('yyyy-MM-dd')
Date startDateValue = nsdf.parse(session.dtstartDate.substring(0, session.dtstartDate.lastIndexOf("T")))
eq("startDate", startDateValue)//if any filter is applied
}
else{
if this is the 1st session the startdate should be null --> need a piece of code to be replaced here
}

Answer 1

I am unsure maybe I still have not got what you have tried to ask properly, I thought I should try to answer your question to how I understood your problem to be.
If we take this basic filter and add some stuff to it we may be able to get to what you wish to do using a better method ? I am unsure what startDate is actually representing but if we base it on if a user has hit a controller for the first time or not the answer would be something like this, you could replace the logic to startDate if it has other significance:
so adding some hashmap arrayset to your filter that gets called before the action is called when user clicks the controller/action:
in your conf/MyFiters.groovy
class MyFilters {
static final Set<HashMap<String[],String[]>> userControl =
([:] as Set).asSynchronized()
//where controller is controllerName and action is actionName
def filters = {
MyLogger() {
before = {
if (verifyClientMaster(session.id as String ,controllerName)==false) {
clientMaster.add(session.id as String:controllerName)
// now here you have a new user so set
// some session value for gsp or load something
//according
}else{
// user has hit it before do something else or set something else
}
}
}
}
}
Boolean verifyClientMaster(String sessionId,String controller) {
// iterate
boolean found = false
userControl.each { k,v -> if (k == sessionId && v == controller) {
found = true
}
}
}
something like this and you know if the user has hit the controller or not.. remember the session is per user. so a new user has a new session entity.
Hope it is of help and not off track..
E2A
Thinking about it you do go down this route then you would need to keep track of when session expires and to remove the user from clientMaster.. take a look at this project if you did go down this route.. personally I would even do it simpler than this... on a rethink...
class MyFilters {
def filters = {
MyLogger() {
before = {
if (!sessions."${controllerName}") {
sessions."${controllerName}"="${controllerName}"
// now here you have a new user so set
// some session value for gsp or load something
//according
}else{
// user has hit it before do something else or set something else
}
}
}
}
}
and even simple than any of this would be to use the intelligence built into a gsp if what you load can be based on it... (not tested any of it ha)
<g:if test="${!session."${controllerName}"}">
<g:set var="${controllerName}" value="${controllerName}" scope="session" />
<g:render template="firstTimeHitter"/>
</g:if>
<g:else>
<g:render template="secondTimeHitter"/>
</g:else>
or just your controller that checks and sets that and either renders something different or sets something gsp picks up on..
def myController {
def doSomething() {
boolean firstTime = false
if (!session."${controllerName}") {
// first time either render or set firsTime
firstTime = true
session."${controllerName}" = controllerName // or startDate
// render view: 'firstTime, model: [firstTime:firstTime, params:params]
} else{
// render view: 'firstTime, model: [firstTime:firstTime, params:params]
}
// if no render above:
render view: 'doSomething, model: [firstTime:firstTime, params:params]
// now in doSomething gsp you look for firstTime:
}
do someThing:
<g:if test="${firstTime.toString().equals('true')}">
<g:render template="firstTimeHitter"/>
</g:if>
<g:else>
<g:render template="secondTimeHitter"/>
</g:else>
The possibilities are endless, the differences being with a filter its a one fits all, i.e. it is checking every controller as it is hit by each user. In controller and gsp solution you have to declare it where needed. You could have an abstract controller that other controllers extend to repeat that check as a higher class that gets called to verify, regardless their all a lot more repetitive than a simple one off filter...
Final Edit to give other other alternatives would be:
final Set<Session> jsessions = ([] as Set).asSynchronized()
jsessions.add('controller1')
jsessions.add('controller2')
jsessions.add('controller3')
jsessions.add(controllerName)
println "=== ${jsessions}"
if (jsessions.contains(controllerName)) {
println "--- We have ${controllerName} defined in our session set.... jsessions"
}
ArrayList jsessions2 = []
jsessions2.add(controllerName)
session.jsessions2 = jsessions2
//repeat this on every call
ArrayList jsessionsret = session.jsessions2
jsessionsret.add('controller1')
jsessionsret.add('controller2')
jsessionsret.add('controller3')
session.jsessions2 = jsessionsret
if (jsessions2.contains(controllerName)) {
println "--- We have ${controllerName} defined in our session set.... jsessionsret"
}
println "222 --- ${jsessions2}"
This segment above are two different implementations of using first a session set that is global and could be used if you do not care if the controller is hit by usera userb etc so if usera hits it userb would also be considered as hitting it.. This is jsessions.
The bottom jsessions2 is an attempt to turn a single session key into an ArrayList. So rather than storing lots of single object i.e. session."${controllerName}" per call of a controller per user session. You could have 1 single session key per user that you append each controller they hit to.. and you then check to see if they have that controller