Hi, starting a project of mine, I've setup a dispatch rule and a function to
return the response.
To make things simple, I've used response/output, with a lambda writing to the
output-port.
However, I've got the error:
response/output: contract violation
expected: void?
given: 11
in: the range of
the 1st argument of
(->*
((-> output-port? void?))
(#:code
number?
#:headers
(listof header?)
#:message
bytes?
#:mime-type
(or/c bytes? #f)
#:seconds
number?)
response?)
contract from:
<pkgs>/web-server-lib/web-server/http/response-structs.rkt
blaming: /home/amatheus/Dropbox/focus/todagendas/teste.rkt
(assuming the contract is correct)
at: <pkgs>/web-server-lib/web-server/http/response-structs.rkt:41.2
context...:
/usr/share/racket/collects/racket/contract/private/blame.rkt:143:0:
raise-blame-error16
/usr/share/racket/pkgs/web-server-lib/web-server/http/response.rkt:115:12
So I've tried to use a response, with the same lambda, and it worked.
From the error message, I changed the lambda to return (void) and then it
worked.
I think maybe the contract is wrong but frankly I don't understand much about
contracts.
I've setup some code that exposes the problem. Navigating to "/working" and
"/fixed" works
fine; navigating to "/not-working" exposes the problem.
#lang racket
(require web-server/dispatch
web-server/servlet-env
net/url
web-server/http/request-structs
web-server/http/response-structs)
(define (not-working req)
(response/output (λ (op) (write-bytes #"Hello world" op))))
(define (working req)
(response
301 #"OK"
(current-seconds) TEXT/HTML-MIME-TYPE
empty
(λ (op) (write-bytes #"Hello world" op))))
(define (fixed req)
(response/output (λ (op) (write-bytes #"Hello world" op) (void))))
(define (url->request u)
(make-request #"GET" (string->url u) empty
(delay empty) #f "1.2.3.4" 80 "4.3.2.1"))
(define-values (agenda-dispatch agenda-url)
(dispatch-rules
[("working") working]
[("not-working") not-working]
[("fixed") fixed]))
(define (main)
(serve/servlet agenda-dispatch
#:servlet-regexp #rx""
#:servlet-path ""))
(module+ main
(main))
The contracts in response-structs.rkt:
(provide/contract
[struct response
([code number?]
[message bytes?]
[seconds number?]
[mime (or/c false/c bytes?)]
[headers (listof header?)]
[output (output-port? . -> . void)])]
[response/full (-> number? bytes? number? (or/c false/c bytes?) (listof
header?) (listof bytes?) response?)]
[response/output (->* ((-> output-port? void?))
(#:code number?
#:message bytes?
#:seconds number?
#:mime-type (or/c bytes? #f)
#:headers (listof header?))
response?)]
[TEXT/HTML-MIME-TYPE bytes?])
Is the contract wrong or am I doing something weird?
Thanks,
André
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