[bknr-devel] BKNR web, best place to start digging

[Frederico Muñoz]

Hello,

I've been trying to find out why I can't get any of the projects to
work, and I've at least a reasonable idea why. Now, I don't know is
this is because I'm doing something wrong or if something has changed
in terms of what hunchentoot expects... I find the later strange since
it would be quite visible, but at this stage I haven't got any other
idea.

Apologies for the length of this message (and feel free to disregard
it if tackling this would consume to much time).

I've traced how things work (simplified, I'm leaving authentication
checking out):

1) BKNR adds an handler to hunchentoot's *dispatch-table*
2) Creating a website (a singleton, referenced by *website*) instance
adds the handlers to the bknr website-handlers
3) When a page is requested the bknr-dispatch handle is called by hunchentoot
4) bknr-dispatch inspects the *request* to see if there is a match for
the uri in the website handlers
5) If there is, calls invoke-handle with the handler as an argument
6) invoke-handle does some housekeeping, and then calls (handle handler).
7) This reaches a custom method, made for whatever class was specified
in website instance. In my test it just produces some HTML

And here is where things stop working: my simple test (a website class
with one single handler, a handler class and a handle-object method)
works up until this point, but it doesn't seem to produce what
hunchentoot expects: just as the quickhoney project (and the
hello-web) I get something like:

-----
The value "<?xml version=\"1.0\" encoding=\"UTF-8\"?>
(... rest of produced HTML by the handle-object above...)
is not of type
  (OR FUNCTION SYMBOL).
------

I'm very far from an expert in any of the components involved, so I've
quite likely omitted some important step. By reading the hunchentoot
docs I gathered that when it polls the handlers in the
*dispatch-table* it expects as return value either a handler (from
what I've gathered, a symbol representing a function name) or nil. I
*think* that this could be the problem. Indeed, if I change my
handle-object method from:

-----
(defmethod handle-object ((handler hello-object-handler) object)
  (with-bknr-page (:title "demo handler")
    (html (:p "This is the demo handler"))))
-----
to
-----
(defmethod handle-object ((handler hello-object-handler) object)
  'handle-object2)
                     ))

(defun  handle-object2 ()
    (with-bknr-page (:title "Debug")
      (html (:p "This is the demo handler"))))
-----

it starts working: hunchentoot got a symbol as return value, and
promptly calls it.


What I find strange here is that I'm using the hunchentoot from the
bknr trunk repo, so this isn't an issue with a new release.

Regards,

Frederico