[cl-who-devel] CL-WHO transformation rule not working?

Wed Nov 15 06:58:12 UTC 2006

On Tuesday 14 November 2006 21:28, Edi Weitz wrote:
> Hi!
>
> On Tue, 14 Nov 2006 18:00:34 +0200, Nico de Jager <ndj at hivsa.com> wrote:
> > It seems that the last transformation rule (and example) for
> > attribute values described in CL-WHO's documentation is not working.
>
> No, it is working.  See below.
>
> > I am using:
> > LispWorks 5.0 for Linux (Debian Sarge)
> > CL-WHO-0.6.2
> > HUNCHENTOOT-0.4.9
> >
> > E.g.
> > (defun logon-page-html () ;logon-action)
> >   (with-html-output (*standard-output*)
> >     (:html
> >      (:head
> >       (:title "test"))
> >      (:body
> >       "Some text"
> >       (:table :border "3"  ; Going to change this!
> >        (:tr (:td "1-1") (:td "1-2")))))))
> >
> > gives the following in 2 browsers:
> > Some text
> > 1-1  1-2
> >
> > html:
> > <html><head><title>test</title></head><body>Some text<table
> > border='3'><tr><td>1-1</td><td>1-2</td></tr></table></body></html>
> >
> > While:
> > (defun logon-page-html () ;logon-action)
> >   (with-html-output (*standard-output*)
> >     (:html
> >      (:head
> >       (:title "test"))
> >      (:body
> >       "Some text"
> >       (:table :border (+ 1 2) ;Substituted (+ 1 2) for "3".
> >        (:tr (:td "1-1") (:td "1-2")))))))
> >
> > only gives the following in the same browsers:
> >>1-11-2
> >
> > html:
> >><tr><td>1-1</td><td>1-2</td></tr></table></body></html>
> >
> > The output of both cl-who:show-html-expansion and cl-who:with-html-output
> > appear correct in the listener, though:
> > CL-USER 11 > (cl-who:show-html-expansion (*standard-output*)
> >                (:html
> >                 (:head
> >                  (:title "test"))
> >                 (:body
> >                  "Some text"
> >                  (:table :border (+ 1 2)
> >                   (:tr (:td "1-1") (:td "1-2"))))))
> >
> > (LET ((*STANDARD-OUTPUT* *STANDARD-OUTPUT*))
> >   (PROGN
> >     NIL
> >     (WRITE-STRING "<html><head><title>test</title></head><body>Some
> > text<table" *STANDARD-OUTPUT*)
> >     (LET ((#:G4088 (+ 1 2)))
> >       (COND ((NULL #:G4088))
> >             ((AND (EQ #:G4088 T) (EQ CL-WHO::*HTML-MODE* :XML)) (PROGN
> > (WRITE-STRING " border='border'" *STANDARD-OUTPUT*)))
> >             ((AND (EQ #:G4088 T) (EQ CL-WHO::*HTML-MODE* :SGML)) (PROGN
> > (WRITE-STRING " border" *STANDARD-OUTPUT*)))
> >             (T (PROGN (WRITE-STRING " border='" *STANDARD-OUTPUT*) (PRINC
> > #:G4088 *STANDARD-OUTPUT*) (WRITE-STRING "'" *STANDARD-OUTPUT*)))))
> >     (WRITE-STRING
> > "><tr><td>1-1</td><td>1-2</td></tr></table></body></html>"
> > *STANDARD-OUTPUT*)))
> >
> > It seems that only the output of the last "write-string" is sent to
> > the browser for the second example.
>
> Your problem is that handlers in Hunchentoot are expected to return a
> string and the string your first handler returns is only by pure
> coincidence the result you wanted to have.  You're sending the "real"
> page to *STANDARD-OUTPUT* where it is not seen by Hunchentoot.
>
> Try to use WITH-HTML-OUTPUT-TO-STRING instead.  That should result in
> the same page in both cases.  Take a look at test/test.lisp in
> Hunchentoot to see how it's done there.
>
> HTH,
> Edi.

Doh! Shame on me! I used TBNL and CL-WHO long ago and did not read the docs 
and examples again to get a proper grasp of it.

Anyway, thanks Edi, and special thanks for all your great work.

Nico