Peter, hello.
On 8 Mar 2016, at 20:41, Peter Bex wrote:
On Tue, Mar 08, 2016 at 02:48:00PM +0000, Norman Gray wrote:
So you mean including handlers like:
(define (vhost-handler cont)
(let ((uri (uri-path (request-uri (current-request)))))
(if (string=? (cadr uri) "wibble") ;; we want to handle URIs
like /wibble/...
(send-response status: 'ok
body: (format "<p>Good: request was ~S
(vhost)</p>" uri)
headers: '((content-type text/html)))
(cont))))
(vhost-map `((".*" . ,vhost-handler)))
That's how it was intended, yes. I've added something similar to the
wiki with a link to slightly extended (but somewhat outdated) example
from a demonstration.
The new section 'A simple dynamic web page example' is perfect, in
combination with the pointer to the spiffy+sxml example.
I marginally adjusted the linked webserver.scm to use sxml-serializer
rather than the full-blown sxml transform egg (was that the 'outdated'
you meant). I've attached the result.
OK: that's a (very) nice design -- I'll do that.
But may I suggest that vhost-map is not, perhaps, the best name for
this structure, since the intended functionality is much more
general than mapping vhosts. As I mentioned, I guessed that might
be a route to the solution, but based on the name, on the fact it's
documented in a section called 'Virtual hosts', and since the
example in that section is about handling virtual hosts, I got the
impression that the author was firmly steering me away from more
open-ended cleverness. Caolan suggested that I'm not (thankfully)
alone in misinterpreting this.
Well, it is a mapping for which handler to use for which vhost. That
is also the topmost place where dispatching happens for incoming
requests, so it's the place where you'd add custom handlers.
I could add some intermediate parameter like "request-handler", which
then defaults to some procedure that handles the request like the
current implementation does (try to serve a file), but it would be
one more level of indirection which is basically just what "continue"
does now.
Would that be sensible?
I don't think that would be necessary and would, as you say, be a
further level of indirection. Yesterday afternoon, I did put together a
potential patch for spiffy.scm which may have the same idea (attached
for interest), but the vhost-map (once one understands what it's
intended for) seems to be completely general.
Perhaps dispatch-handler-map, or handler-map, or something like
that, would signal the intent more clearly, along with an example
such as the above.
Not sure that would be much clearer. Also, it would break
compatibility.
Indeed: it's not obvious what the best name is, though 'handle/host'
seemed to push the right buttons for me.
One would of course export a (define vhost-map fancy-new-name) for
compatibility.
Since the car of the alist is a host pattern,
then perhaps the word 'host' should be in the name, but in that case
perhaps handle/host might be suitable (and if anything's being
changed, then it might be nice to have a clear catch-all host
pattern, such as #t, or to permit the list elements to be a
continuation thunk as well as a string-thunk pair). Thus:
(handle/host
`(,my-general-handler
("foo\\.bar\\.com" . ,(lambda (continue) ...))
(#t . ,my-catch-all-handler))
I think that would only complicate things, and cause more confusion
as to the format of this list.
I agree.
It's a wiki, feel free to improve the wording in places where it's
unclear.
There's nothing I can usefully add to the change you've made, but I'll
bear the suggestion in mind for what I expect to be lots of future
engagement with these docs.
And thanks, Andy, for the pointer to uri-match (and for the mention of
Knodium, which I intend to investigate further).
All the best,
Norman
--
Norman Gray : https://nxg.me.uk
SUPA School of Physics and Astronomy, University of Glasgow, UK
*** /Data/tools/000-Build/spiffy/spiffy.scm 2016-03-08 11:02:20.000000000
+0000
--- spiffy-with-dispatcher.scm 2016-03-08 13:57:45.000000000 +0000
***************
*** 35,41 ****
; ticket tracking system (assign tickets to user 'sjamaan'):
; http://trac.callcc.org
! (module spiffy
(start-server switch-user/group accept-loop
with-headers send-status send-response send-static-file log-to
write-logged-response build-error-message
--- 35,41 ----
; ticket tracking system (assign tickets to user 'sjamaan'):
; http://trac.callcc.org
! (module spiffy-with-dispatcher
(start-server switch-user/group accept-loop
with-headers send-status send-response send-static-file log-to
write-logged-response build-error-message
***************
*** 47,53 ****
default-host vhost-map access-log error-log debug-log
spiffy-user spiffy-group access-file max-connections
handle-file handle-directory handle-not-found handle-exception
! handle-access-logging restart-request htmlize)
(import chicken scheme)
(use extras ports files data-structures srfi-1 srfi-13 srfi-14 srfi-18
--- 47,54 ----
default-host vhost-map access-log error-log debug-log
spiffy-user spiffy-group access-file max-connections
handle-file handle-directory handle-not-found handle-exception
! handle-access-logging restart-request htmlize
! dispatcher default-dispatcher)
(import chicken scheme)
(use extras ports files data-structures srfi-1 srfi-13 srfi-14 srfi-18
***************
*** 480,485 ****
--- 481,494 ----
(lp (cdr address-chain))
(car address-chain))))
+ (define (default-dispatcher req)
+ (debug! "default-dispatcher for request ~S" req)
+ (process-entry
+ "" ""
+ (cdr (uri-path (request-uri req)))))
+
+ (define dispatcher (make-parameter default-dispatcher))
+
(define (handle-incoming-request compiled-vhost-map in out)
(handle-exceptions exn ; This should probably be more fine-grained
(let ((chain (with-output-to-string print-call-chain)))
***************
*** 516,525 ****
(if ir&handler
((cdr ir&handler)
(lambda ()
! (process-entry
! "" ""
! (cdr (uri-path (request-uri
! (current-request)))))))
;; Is this ok?
((handle-not-found)
(uri-path (request-uri (current-request))))))
--- 525,531 ----
(if ir&handler
((cdr ir&handler)
(lambda ()
! ((dispatcher) (current-request))))
;; Is this ok?
((handle-not-found)
(uri-path (request-uri (current-request))))))
(use spiffy simple-directory-handler
spiffy-uri-match intarweb uri-common
sxml-serializer)
(define (send-sxml-response sxml)
(with-headers `((connection close))
(lambda ()
(write-logged-response)))
(serialize-sxml sxml
output: (response-port (current-response))))
(define my-custom-routes
`(((/ "greeting")
(GET ,(lambda _
(let* ((q (uri-query (request-uri (current-request))))
(name (alist-ref 'name q))
(greeting (if (and name (not (string=? name "")))
(sprintf "Hi there, ~A!" name)
"Please type in your name below")))
(send-sxml-response
`(html
(head (title ,greeting))
(body
(h1 ,greeting)
(form
(input (@ (type "text") (name "name")))
(input (@ (type "submit") (value "Go!"))))
(p "If you're bored, you can "
(a (@ (href "/"))
"go back to browsing the docroot")))))))))))
(vhost-map ; Make route matching available on all virtual hosts
`((".*" . ,(uri-match/spiffy my-custom-routes))))
;; Let simple-directory-handler handle directories (default is 304 access
denied)
(handle-directory simple-directory-handler)
(start-server)
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