[wildfly-dev] Taglibs - correct location of TLD files packaged in JARs

[Tomas Hofman]

Hi folks,

we have an issue [0] where a web app with JAR packaged taglib is migrated from 
Tomcat to Wildfly/EAP and the two servers are resolving tablib location 
differently.

The taglib file in the JAR is located in
META-INF/resources/WEB-INF/tlds/hi.tld.

It's added to the taglib map explicitly via <taglib> element in 
web-fragment.xml (in the same JAR):

         <taglib>
             <taglib-uri>/HiTag</taglib-uri>
             <taglib-location>/WEB-INF/tlds/hi.tld</taglib-location>
         </taglib>

This works in Tomcat, which takes *META-INF/resources/* as the root for 
resolving <taglib-location>, and doesn't work in Wildfly, which takes 
*META-INF/* as the root.

The functionality is described by JSP SPEC section 7.3 (I don't want to quote 
any parts here, because I would have to quote all of it) [1]. After going 
through it I think our interpretation is the correct one, though Apache think 
the contrary [2].

However, would it hurt if we added META-INF/resources/ as another root to allow 
both options?


[0] The issue: https://issues.jboss.org/browse/JBEAP-14757
[1] JSP spec: http://download.oracle.com/otndocs/jcp/jsp-2_3-mrel2-eval-spec/
[2] I wrote to Apache mailing list and Jeremy Boynes replied:

"""
Here’s how I read the spec.

JSP 7.3.3 talks about a “taglib map” using elements in the deployment 
descriptor per your example. Per JSP 7.3.2 the URI is mapped to a context 
relative path interpreted relative to the root of the web application. 
Resources contained in a web fragment jar are located in its 
/META-INF/resources directory. Tomcat/Jasper are synthesizing the effective web 
application from the resources in the fragments, then resolving the URI in the 
taglib map against that merged application. I think that’s a correct 
interpretation of the spec.

JSP 7.3.1 refers to implicit map entries found by scanning the web 
application’s jars from WEB-INF/lib.
"""

http://mail-archives.apache.org/mod_mbox/tomcat-taglibs-user/201805.mbox/%3C4E3C404C-1D9F-4292-BE77-C443C3C61671%40apache.org%3E


-- 
Tomas Hofman
Software Engineer, JBoss SET
Red Hat