In a JSP view, how do I test login state, build a node URL, and share constants across views?
Question
In a JSP view, how do I test login state, build a node URL, and share constants across views?
Answer
Login state together with a session attribute
Nothing Jahia-specific is needed - renderContext is an ordinary EL object, so
plain JSTL works:
<c:if test="${renderContext.loggedIn and sessionScope.myAttribute eq 'expected'}">
...
</c:if>renderContext.loggedIn is false for the guest user. Remember that a view is
rendered server-side and may be cached, so a condition on a per-user session
attribute needs the surrounding fragment to be cached per user, or not cached.
Node URLs: pick the right one
Jahia exposes a url object. The two that get confused are:
| EL | What it gives |
|---|---|
${url.current} | the URL of the resource currently being rendered - inside a component view, that is the component, not the page |
${url.mainResource} | the URL of the page (the main resource), as base + path + .template.html |
${url.base} | the base URL for the current workspace and language |
So in a component view, ${url.current} is usually not what you want for
"the page I am on" - that is ${url.mainResource}.
For an arbitrary node, build it from the base:
<c:url var="nodeUrl" value="${url.base}${myNode.path}.html"/>
<a href="${nodeUrl}">...</a>Also available: ${url.live}, ${url.edit}, ${url.preview}, ${url.context},
${url.files}, ${url.logout}, and ${url.language['fr']} for the same resource
in another language.
Constants shared across views
Jahia ships a tag for exactly this. Put your constants in a Java class in your
module as public static final fields, then expose them to EL:
<%@ taglib prefix="utility" uri="http://www.jahia.org/tags/utilityLib" %>
<utility:useConstants var="myConstants"
className="org.example.mymodule.MyConstants"
scope="application"/>
<c:if test="${myNode.primaryNodeTypeName eq myConstants.THING_TYPE}">
...
</c:if>| Attribute | |
|---|---|
var | required - the EL variable the constants map is bound to |
className | required - the fully qualified class whose public static fields are exposed |
scope | optional - page (default), request, session or application |
The tag reads the class's public static constants into an unmodifiable,
case-insensitive map. Using scope="application" means it is resolved once
rather than per render.
This is the supported alternative to repeating literals in every view, or to
<%@ include %> of a fragment of <c:set> declarations.
Two practical notes:
- The class must be visible to your module's classloader - putting it in the module that contains the views is the simple case.
- No JSP shipped in Jahia core uses this tag, so you will not find an in-tree example to copy; the tag and its contract are nonetheless part of the core taglib.
This article was drafted with AI assistance, then reviewed and curated by Jahia Customer Support engineers before publication.