My router doesn't work as expected - meteor

Question

this is the router code
Router.route('screens', {
path: '/screenshots/:_id',
template: 'screens',
onBeforeAction: function(){
Session.set( "currentRoute", "screens" );
Session.set("screenshots", this.params._id);
this.next();
}
});
this is the helper for screenshots template
Template.screens.helpers({
ss: function () {
var screenshots = Session.get("screenshots");
return Products.findOne({ _id: screenshots});
}
});
and am calling it here
<h4>Click to view the Screenshots
When i click to view the screenshots URL, the URL should be this /screenshots/:_id based on my router configuration, but what i see in the browser is /screenshots/ without the _id and the page shows 404 - NOT FOUND.
Is it possible to create nested routes?
because before i click on the link that executes the above route. i will be in this route
Router.route('itemDetails', {
path: '/item/:_id',
template: 'itemDetails',
onBeforeAction: function(){
Session.set( "currentRoute", "itemDetails" );
Session.set("itemId", this.params._id);
this.next();
}
});
and this route works fine i can see the item _id, is it possible to create another route inside it that has for example this path /item/:_id/screenshots?
I have the _id stored in Session.get("itemId"). Is it possible to call it in the path of the route somehow?
I tried '/item' + '/screenshots' + '/' + Session.get("itemId") but didn't work
or there is other way to solve it?

Answer 1

The problem is not with the code in the question, the 404 page is occurring due to it not being passed an id into the path, the browser says /screenshots/ and not /screenshots/randomId because it is only being passed that from the link.
As per additions to the question and chat with Behrouz: Because the value is stored in session we can use
Template.registerHelper('session',function(input){
return Session.get(input);
});
to register a global template helper called session which can be called with {{session session_var_name}} and create the link as below:
<h4>Click to view the Screenshots