[tbnl-devel] arbitrary per-request data?

[Zach Beane]

I have an application that has a notion of a current user that is
lazily established on a per-request basis. For now, I have been
returning a handler that is really a lambda wrapping a real handler
that lexically binds the special *current-user*:

   (defun page-handler (request)
     (multiple-value-bind (handler foundp)
         (gethash (script-name request) *handlers*)
       (when foundp
         (lambda ()
           (let ((*current-user* *current-user-local-unbound-value*))
             (funcall handler))))))

But it occurred to me that there is already the *request*
structure. Would it make sense to be able to have a table of arbitrary
keys and values in the request structure for application use? I was
thinking of an accessor like this:

   request-data key &optional (request *request*) => value, foundp

Then I could write CURRENT-USER something like:

   (defun current-user ()
     (multiple-value-bind (value foundp)
         (request-data 'user)
       (if foundp
           value
           (setf (request-data 'user) (cookie-user)))))

Right now it's a bit messier than that.

What do you think? If this seems reasonable I can work out and submit
a patch.

Zach