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;;; www/url.scm --- URL manipulation tools
;; Copyright (C) 1997,2001,2002 Free Software Foundation, Inc.
;;
;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this software; see the file COPYING. If not, write to
;; the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
;; Boston, MA 02111-1307 USA
;;
;;; Commentary:
;; This module exports the following procedures:
;; (url:scheme url)
;; (url:address url)
;; (url:unknown url)
;; (url:user url)
;; (url:host url)
;; (url:port url)
;; (url:path url)
;; (url:make scheme . args)
;; (url:make-http host port path)
;; (url:make-ftp user host port path)
;; (url:make-mailto address)
;; (url:parse url)
;; (url:unparse url)
;; (url:decode str)
;; (url:encode str reserved-chars)
;;; Code:
;; TODO:
;; * support `user:password@' strings where appropriate in URLs.
;; * make URL parsing smarter. This is good for most TCP/IP-based
;; URL schemes, but parsing is actually specific to each URL scheme.
;; * fill out url:encode, include facilities for URL-scheme-specific
;; encoding methods (e.g. a url-scheme-reserved-char-alist)
(define-module (tekuti url)
#:use-module (ice-9 regex))
;; `url:scheme' is an unfortunate term, but it is the technical
;; name for that portion of the URL according to RFC 1738. Sigh.
(define-public (url:scheme url) (vector-ref url 0))
(define-public (url:address url) (vector-ref url 1))
(define-public (url:unknown url) (vector-ref url 1))
(define-public (url:user url) (vector-ref url 1))
(define-public (url:host url) (vector-ref url 2))
(define-public (url:port url) (vector-ref url 3))
(define-public (url:path url) (vector-ref url 4))
(define-public (url:make scheme . args)
(apply vector scheme args))
(define-public (url:make-http host port path)
(vector 'http #f host port path))
(define-public (url:make-ftp user host port path)
(vector 'ftp user host port path))
(define-public (url:make-mailto address)
(vector 'mailto address))
(define http-regexp (make-regexp "^http://([^:/]+)(:([0-9]+))?(/(.*))?$"))
(define ftp-regexp
(make-regexp "^ftp://(([^@:/]+)@)?([^:/]+)(:([0-9]+))?(/(.*))?$"))
(define mailto-regexp (make-regexp "^mailto:(.*)$"))
(define-public (url:parse url)
(cond
((regexp-exec http-regexp url)
=> (lambda (m)
(url:make-http (match:substring m 1)
(cond ((match:substring m 3) => string->number)
(else #f))
(match:substring m 5))))
((regexp-exec ftp-regexp url)
=> (lambda (m)
(url:make-ftp (match:substring m 2)
(match:substring m 3)
(cond ((match:substring m 5) => string->number)
(else #f))
(match:substring m 7))))
((regexp-exec mailto-regexp url)
=> (lambda (m)
(url:make-mailto (match:substring m 1))))
(else
(url:make 'unknown url))))
(define-public (url:unparse url)
(define (pathy scheme username url) ; username not used!
(format #f "~A://~A~A~A"
scheme
(url:host url)
(cond ((url:port url) => (lambda (port) (format #f ":~A" port)))
(else ""))
(cond ((url:path url) => (lambda (path) (format #f "/~A" path)))
(else ""))))
(case (url:scheme url)
((http) (pathy 'http #f url))
((ftp) (pathy 'ftp (url:user url) url))
((mailto) (format #f "mailto:~A" (url:address url)))
((unknown) (url:unknown url))))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; (url-decode STR)
;; Turn + into space, and hex-encoded %XX strings into their
;; eight-bit characters. Is a regexp faster than character
;; scanning? Does it incur more overhead (which may be more
;; important for code that frequently gets restarted)?
(define-public (url:decode str)
(regexp-substitute/global
#f "\\+|%([0-9A-Fa-f][0-9A-Fa-f])" str
'pre
(lambda (m)
(cond ((string=? "+" (match:substring m 0)) " ")
(else (integer->char
(string->number
(match:substring m 1)
16)))))
'post))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; (url-encode STR)
;; The inverse of url-decode. Can't be done easily with
;; a regexp: we would have to construct a regular expression
;; like "[\277-\377]", for example, and Guile strings don't
;; let you interpolate character literals. Pity.
;; URL-encode any characters in STR that are not safe: these
;; include any character not in the SAFE-CHARS list and any
;; character that *is* in the RESERVED-CHARS list argument.
(define-public (url:encode str reserved-chars)
(with-output-to-string
(lambda ()
(for-each (lambda (ch)
(if (and (safe-char? ch)
(not (memv ch reserved-chars)))
(display ch)
(begin
(display #\%)
(display (number->string (char->integer ch) 16)))))
(string->list str)))))
(define safe-chars
'(#\$ #\- #\_ #\. #\+ #\! #\* #\' #\( #\) #\, #\; #\/ #\? #\: #\@ #\& #\=))
(define (safe-char? ch)
;; ``Thus, only alphanumerics, the special characters "$-_.+!*'(),", and
;; reserved characters used for their reserved purposes may be used
;; unencoded within a URL.'' RFC 1738, #2.2.
(or (char-alphabetic? ch)
(char-numeric? ch)
(memv ch safe-chars)))
;;; www/url.scm ends here
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