I think there is some kind of fall-back sequence coded in one of the
Velocity context implementations where if a key is not found in the context
then it is also looked up as a request parameter, session attribute, etc.
If I remember correctly it is in the ViewToolContext class.
On Thu, Jan 5, 2012 at 4:15 PM, Christopher Schultz <
ch...@christopherschultz.net> wrote:
> All,
>
> On 1/5/12 4:05 PM, Christopher Schultz wrote:
> > I found some errors in my log file about a particular 'layout' not being
> > found. Coincidentally, I had a request parameter called "layout" with
> > some data in it and it seemed to be triggering a change to the layout
> > file that VelocityViewServlet attempts to use.
>
> I am using a custom subclass of VelocityViewServlet that changes the
> error handling and also the Context creation by taking the user's Struts
> locale and putting it into the Context. Here's the method:
>
> protected Context createContext(HttpServletRequest request,
> HttpServletResponse response)
> {
> Context ctx = super.createContext(request, response);
>
> // Don't clobber an existing key
> if(!ctx.containsKey("locale"))
> {
> Locale locale = null;
> HttpSession session = request.getSession(false);
> if(null != session)
> locale = (Locale)session.getAttribute(Globals.LOCALE_KEY);
>
> if(null == locale)
> locale = request.getLocale();
>
> ctx.put("locale", locale);
> }
>
> // DEBUG
> System.err.println("createContext: 'layout'="
> + ctx.get("layout"));
> ctx.put("theContext", ctx);
> return ctx;
> }
>
> I added that debugging code at the bottom, and the log confirms that, at
> this stage, 'layout' is null in the context. I stuck the 'theContext'
> into itself so I could inspect it from the page, like this:
>
> request: $!request.getParameter('layout')
> context: $!theContext.get('layout')
> app: $!request.servletContext.getAttribute('layout')
> bare layout = $!layout
>
> The output from this template displays the following:
>
> request: Help.vm
> context: Help.vm
> app:
> bare layout: Help.vm
>
> So, somehow the request parameter is in fact being copied into the
> velocity context, where it affects VelocityLayoutServlet's rendering of
> the page.
>
> I'll get a stack trace of where the context key is being set, next.
>
> -chris
>
>
