When you use #lang web-server
You have to use web-server/lang/web --- http://docs.racket-lang.org/web-server/stateless.html#(part._lang/web) rather than web-server/servlet/web (which you are getting from web-server/servlet) The problem is that your send/suspend/dispatch is the STATEFUL one, not the STATELESS one and so there is no state instance available. Jay On Fri, Aug 24, 2012 at 8:38 AM, J G Cho <g...@fundingmatters.com> wrote: > So I have a module that runs fine in a web server. However when I > tried it in "stateless" server, it fails (msg: No instance for id: 1) > with a very short stacke trace. I run it by itself using (module+ main > ...) then it runs but it does not work as intended (more on this > below). > > So here are "toy" versions of what my module does which produces > similar behavior. > > First, the version that works (uses the attached file as template): > > #lang racket > > (require web-server/servlet > web-server/templates) > > ;; insert into UI Template and then dish out HTML > (define (form-template msg k-url output) > (response/full > 200 #"Okay" > (current-seconds) TEXT/HTML-MIME-TYPE > empty > (list (string->bytes/utf-8 (include-template "ui.html"))))) > > (define (all-ups xs) > (if (null? xs) > "" > (string-append (string-upcase (car xs)) > "<br/>" > (all-ups (cdr xs))))) > > (define (main-loop txts parser helper) > (local [(define (response-generator embed/url) > (form-template > (helper (reverse txts)) > (embed/url next-text-handler) > (format "~a" (parser (reverse txts))))) > > (define (next-text-handler req) > (main-loop (cons (extract-binding/single 'quote > (request-bindings req)) > txts) > parser > helper))] > > (send/suspend/dispatch response-generator))) > > (define (start initial-req) > (main-loop '() > (lambda (xs) > (cond > [(null? xs) "To undo, just go back (short-cut > alt+left arrow)."] > [else (all-ups xs)])) > (lambda (xs) > (cond > [(null? xs) "Start:"] > [else (format "Input ~a: ready for more." (add1 > (length xs)))])))) > > (provide start) > > (module+ main > (require web-server/servlet-env) > > (serve/servlet start > #:quit? #t > #:listen-ip #f > #:log-file "debug.log" #:port 8082 #:launch-browser? #t > #:log-format 'parenthesized-default > #:servlet-path "/quotes")) > > Here is the version that does not work (main difference is in module+ area): > > #lang racket > > (require web-server/servlet > web-server/templates) > > ;; insert into UI Template and then dish out HTML > (define (form-template msg k-url output) > (response/full > 200 #"Okay" > (current-seconds) TEXT/HTML-MIME-TYPE > empty > (list (string->bytes/utf-8 (include-template "ui.html"))))) > > (define (all-ups xs) > (if (null? xs) > "" > (string-append (string-upcase (car xs)) > "<br/>" > (all-ups xs)))) > > (define (main-loop txts parser helper) > (local [(define (response-generator embed/url) > (form-template > (helper (reverse txts)) > (embed/url next-text-handler) > (format "~a" (parser (reverse txts))))) > > (define (next-text-handler req) > (main-loop (cons (extract-binding/single 'quote > (request-bindings req)) > txts) > parser > helper))] > > (send/suspend/dispatch response-generator))) > > (define (start initial-req) > (main-loop '() > (lambda (xs) > (cond > [(null? xs) "To undo, just go back (short-cut > alt+left arrow)."] > [else (all-ups xs)])) > (lambda (xs) > (cond > [(null? xs) "Start:"] > [else (format "Input ~a: ready for more." (add1 > (length xs)))])))) > > (provide start) > > (module+ main > (require web-server/servlet-env > web-server/stuffers) > > (define stuffer > (stuffer-chain > serialize-stuffer > (md5-stuffer (build-path (current-directory) "urls")))) > > (serve/servlet start > #:quit? #t > #:listen-ip #f > #:log-file "debug.log" #:port 8082 #:launch-browser? #t > #:log-format 'parenthesized-default > #:stateless? #t #:stuffer stuffer > #:servlet-path "/quotes")) > > The failed version seems to have no memory (ie the previous inputs are > NOT available). > > How can I fix this? > > jGc > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users > -- Jay McCarthy <j...@cs.byu.edu> Assistant Professor / Brigham Young University http://faculty.cs.byu.edu/~jay "The glory of God is Intelligence" - D&C 93 ____________________ Racket Users list: http://lists.racket-lang.org/users
