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Abstracting parameters

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svn: r6384
This commit is contained in:
Jay McCarthy 2007-05-29 18:11:01 +00:00
parent f8dd838409
commit d8d99e619a
1 changed files with 21 additions and 15 deletions
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26
collects/web-server/prototype-web-server/private/session.ss
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@ -48,36 +48,42 @@
;; encode-session : url number -> url
(define (encode-session a-url ses-id)
(insert-param a-url (number->string ses-id)))
(insert-param a-url 's (number->string ses-id)))
;; extract-session url -> (union number #f)
;; extract-session : url -> (union number #f)
;; Determine if the url encodes a session-id and extract it
(define (extract-session a-url)
(define (match-url-params x) (regexp-match #rx"([0-9]+)" x))
(define id (extract-param a-url "s"))
(with-handlers ([exn? (lambda _ #f)])
(string->number id)))
;; extract-param : url string -> string
(define (extract-param url key)
(define (match-url-params x) (regexp-match (format "^~a=(.+)$" key) x))
(let ([k-params (filter match-url-params
(apply append
(map path/param-param (url-path a-url))))])
(map path/param-param (url-path url))))])
(if (empty? k-params)
#f
(match (match-url-params (first k-params))
[(list _ n)
(string->number n)]
[(list _ val)
val]
[_
#f]))))
;; insert-param: url string -> string
;; insert-param : url string string -> url
;; add a path/param to the path in a url
;; (assumes that there is only one path/param)
(define (insert-param in-url new-param-str)
(define (insert-param in-url key new-param-str)
(replace-path
(lambda (old-path)
(if (null? old-path)
(list (make-path/param "" (list new-param-str)))
(list (make-path/param "" (list (format "~a=~a" key new-param-str))))
(let* ([car-old-path (car old-path)])
(cons (make-path/param (if (path/param? car-old-path)
(path/param-path car-old-path)
car-old-path)
(list new-param-str))
(list (format "~a=~a" key new-param-str)))
(cdr old-path)))))
in-url))