Check whether you are on author or publish

How do I check if the code is running on an author or a publish instance?

Solution

DeliveryHttpServletRequest cqRequest = (DeliveryHttpServletRequest) request;

// flag to indicate whether application is Author or Publish
boolean isAdmin = !cqRequest.getCmsService().getDisplayControlSet(cqRequest).equals(DisplayControlSet.SHOW);

// flag to indicate whether application is in preview/show mode
boolean isShowMode = (cqRequest.getCmsService().getDisplayControlSet(cqRequest).equals(DisplayControlSet.SHOWMODE)
|| "ShowMode".equals(cqRequest.getParameter("Show")) );

This method is better than checking the URL, because this code does nor rely on a specific context, which can change. Also, the author server can be switched to a publish mode by setting parameter "Show" to 1 in the request. So, the request to /author/somepage.html?Show=1 renders as publish. Therefore, relying on the context is not a reliable solution.