Tracing sling jsp resolution & use of selectors vs variables - aem

Question

In adobe AEM (aka cq), for a given url is it possible to see what jsp's are being invoked?
We've got example code, not written by us where 2 sets of 'base' jsp are being matched if a specific selector is present or not - 'm' for mobile.
In the base jsp a variable is then set to flag if a mobile or desktop device is requesting.
From then on no further selectors are used - just checks on the variable to specifically include mobile specific jsp or not.
A different approach from solely using selectors to invoke specific jsp or not.
By having the script resolution traced it helps visualise and debuts, but is this a common pattern for sling based code?

Answer 1

You can see details about the most recent requests in the Web Console, the Recent Requests tab ( http://localhost:4502/system/console/requests for a local author instance ).
The output is similar to the one below, and it should give you enough information
0 (2013-09-14 21:36:20) TIMER_START{Request Processing}
0 (2013-09-14 21:36:20) COMMENT timer_end format is {<elapsed msec>,<timer name>} <optional message>
0 (2013-09-14 21:36:20) LOG Method=GET, PathInfo=/.edit.html
0 (2013-09-14 21:36:20) TIMER_START{ResourceResolution}
1 (2013-09-14 21:36:20) TIMER_END{1,ResourceResolution} URI=/.edit.html resolves to Resource=JcrNodeResource, type=sling:redirect, superType=null, path=/
1 (2013-09-14 21:36:20) LOG Resource Path Info: SlingRequestPathInfo: path='/', selectorString='edit', extension='html', suffix='null'
1 (2013-09-14 21:36:20) TIMER_START{ServletResolution}
1 (2013-09-14 21:36:20) TIMER_START{resolveServlet(JcrNodeResource, type=sling:redirect, superType=null, path=/)}
1 (2013-09-14 21:36:20) TIMER_END{0,resolveServlet(JcrNodeResource, type=sling:redirect, superType=null, path=/)} Using servlet /libs/sling/servlet/default/edit.jsp
1 (2013-09-14 21:36:20) TIMER_END{0,ServletResolution} URI=/.edit.html handled by Servlet=/libs/sling/servlet/default/edit.jsp
1 (2013-09-14 21:36:20) LOG Applying Requestfilters
1 (2013-09-14 21:36:20) LOG Calling filter: org.apache.sling.engine.impl.debug.RequestProgressTrackerLogFilter
1 (2013-09-14 21:36:20) LOG Calling filter: org.apache.sling.explorer.post.POSTServletFilter
1 (2013-09-14 21:36:20) TIMER_START{/libs/sling/servlet/default/edit.jsp#0}
3 (2013-09-14 21:36:20) LOG Including resource JcrNodeResource, type=sling:redirect, superType=null, path=/ (SlingRequestPathInfo: path='/', selectorString='head', extension='html', suffix='null')
3 (2013-09-14 21:36:20) TIMER_START{resolveServlet(JcrNodeResource, type=sling:redirect, superType=null, path=/)}
3 (2013-09-14 21:36:20) TIMER_END{0,resolveServlet(JcrNodeResource, type=sling:redirect, superType=null, path=/)} Using servlet /libs/sling/servlet/default/head.jsp

Answer 2

You can also find out which script or servlet will process a request using the ServletResolver service:
Servlet servlet = servletResolver.resolveServlet(slingRequest);
RequestUtil.getServletName(servlet);

Answer 3

As #robert_munteanu showed, the requests tab on the system console is the best place to track the processing of your requests.
This is common idiom in Sling applications. Different JSPs are used for GET/POST requests, requests containing selectors or requests with different extensions.
Take a look at the Sling Cheatsheet to understand how this works at high level, or at the Sling ScriptSelectionTest unit test, which explores a broader range of use cases.