racket/collects/web-server/lang/web.ss
2008-08-25 19:57:34 +00:00

91 lines
2.9 KiB
Scheme

#lang scheme
(require net/url
scheme/contract
scheme/serialize
web-server/private/request-structs
web-server/private/response-structs
web-server/private/define-closure
"../private/request-structs.ss"
"abort-resume.ss"
"../private/session.ss"
"stuff-url.ss"
"../private/url-param.ss")
(provide
;; Server Interface
initialize-servlet
;; Servlet Interface
send/suspend/hidden
send/suspend/url
send/suspend/dispatch)
; These contracts interfere with the continuation safety marks
#;(provide/contract
;; Server Interface
[initialize-servlet ((request? . -> . response?) . -> . (request? . -> . response?))]
;; Servlet Interface
[send/suspend/hidden ((url? list? . -> . response?) . -> . request?)]
[send/suspend/url ((url? . -> . response?) . -> . request?)]
[send/suspend/dispatch ((((request? . -> . any/c) . -> . url?) . -> . response?)
. -> . any/c)])
;; initial-servlet : (request -> response) -> (request -> response?)
(define (initialize-servlet start)
(let ([params (current-parameterization)])
(lambda (req0)
(call-with-parameterization
params
(lambda ()
(dispatch
(lambda (req1)
(or (request->continuation req1)
; Try to decode a continuation from the request,
; or, use the start procedure to initialize a session
(lambda (req2) (dispatch-start start req2))))
req0))))))
;; send/suspend/hidden: (url input-field -> response) -> request
;; like send/suspend except the continuation is encoded in a hidden field
;; XXX incorporate stuffing in some way
(define (send/suspend/hidden page-maker)
(send/suspend
(lambda (k)
(let ([p-cont (serialize k)])
(page-maker
(session-url (current-session))
`(input ([type "hidden"] [name "kont"] [value ,(format "~s" p-cont)])))))))
;; send/suspend/url: (url -> response) -> request
;; like send/suspend except the continuation is encoded in the url
(define (send/suspend/url page-maker)
(send/suspend
(lambda (k)
(page-maker
(stuff-url k
(session-url (current-session)))))))
(define-closure embed/url (proc) (k)
(stuff-url (kont-append-fun k proc)
(session-url (current-session))))
(define (send/suspend/dispatch response-generator)
(send/suspend
(lambda (k)
(response-generator (make-embed/url (lambda () k))))))
;; request->continuation: req -> continuation
;; decode the continuation from the hidden field of a request
(define (request->continuation req)
(or
; Look in url for c=<k>
(let ([req-url (request-uri req)])
(and (stuffed-url? req-url)
(unstuff-url
req-url)))
; Look in query for kont=<k>
(match (bindings-assq #"kont" (request-bindings/raw req))
[(struct binding:form (id kont))
(deserialize (read (open-input-bytes kont)))]
[_ #f])))