46 lines
1.5 KiB
Racket
46 lines
1.5 KiB
Racket
#lang racket/base
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(require racket/contract
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net/url
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racket/match
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racket/list
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"util.rkt")
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(provide/contract
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[extract-param (url? string? . -> . (or/c string? false/c))]
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[insert-param (url? string? string? . -> . url?)])
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;; extract-param : url string -> string
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(define (extract-param url key)
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(define ps
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(apply append
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(map path/param-param (url-path url))))
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(let/ec esc
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(for-each (lambda (p)
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(with-handlers ([exn:fail? void])
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(define l (read/string p))
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(esc (cdr (assoc key l)))))
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ps)
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#f))
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;; insert-param : url string string -> url
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;; add a path/param to the path in a url
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;; (assumes that there is only one path/param)
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(define (insert-param in-url key val)
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(url-replace-path
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(match-lambda
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[(list)
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(list (make-path/param
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""
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(list (write/string (list (cons key val))))))]
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[old
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(match (reverse old)
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[(list-rest f r)
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(reverse (list* (make-path/param
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(path/param-path f)
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(list (write/string
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(list* (cons key val)
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(with-handlers ([exn:fail? (lambda _ empty)])
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(filter (lambda (k*v) (not (equal? key (car k*v))))
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(read/string (first (path/param-param f)))))))))
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r))])])
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in-url))
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