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;;; url-methods.el --- Load URL schemes as needed
;; Author: $Author: wmperry $
;; Created: $Date: 2002/11/04 14:40:32 $
;; Version: $Revision: 1.14 $
;; Keywords: comm, data, processes, hypermedia
;;; Copyright (c) 1993 - 1996 by William M. Perry <>
;;; Copyright (c) 1996 - 1999 Free Software Foundation, Inc.
;;; This file is part of GNU Emacs.
;;; GNU Emacs 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.
;;; GNU Emacs is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; GNU General Public License for more details.
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Emacs; see the file COPYING. If not, write to the
;;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;;; Boston, MA 02111-1307, USA.
(require 'cl))
;; This loads up some of the small, silly URLs that I really don't
;; want to bother putting in their own separate files.
(require 'url-auto)
(require 'url-parse)
(defvar url-scheme-registry (make-hash-table :size 7 :test 'equal))
(defconst url-scheme-methods
'((default-port . variable)
(asynchronous-p . variable)
(expand-file-name . function)
(file-exists-p . function)
(file-attributes . function)
(parse-url . function)
(file-symlink-p . function)
(file-writable-p . function)
(file-directory-p . function)
(file-executable-p . function)
(directory-files . function)
(file-truename . function))
"Assoc-list of methods that each URL loader can provide.")
(defconst url-scheme-default-properties
(list 'name "unknown"
'loader 'url-scheme-default-loader
'default-port 0
'expand-file-name 'url-identity-expander
'parse-url 'url-generic-parse-url
'asynchronous-p nil
'file-directory-p 'ignore
'file-truename (lambda (&rest args)
(url-recreate-url (car args)))
'file-exists-p 'ignore
'file-attributes 'ignore))
(defun url-scheme-default-loader (url &optional callback cbargs)
"Signal an error for an unknown URL scheme."
(error "Unkown URL scheme: %s" (url-type url)))
(defun url-scheme-register-proxy (scheme)
"Automatically find a proxy for SCHEME and put it in `url-proxy-services'."
(let* ((env-var (concat scheme "_proxy"))
(env-proxy (or (getenv (upcase env-var))
(getenv (downcase env-var))))
(cur-proxy (assoc scheme url-proxy-services))
(urlobj nil))
;; Store any proxying information - this will not overwrite an old
;; entry, so that people can still set this information in their
;; .emacs file
(cur-proxy nil) ; Keep their old settings
((null env-proxy) nil) ; No proxy setup
;; First check if its something like hostname:port
((string-match "^\\([^:]+\\):\\([0-9]+\\)$" env-proxy)
(setq urlobj (url-generic-parse-url nil)) ; Get a blank object
(url-set-type urlobj "http")
(url-set-host urlobj (match-string 1 env-proxy))
(url-set-port urlobj (string-to-number (match-string 2 env-proxy))))
;; Then check if its a fully specified URL
((string-match url-nonrelative-link env-proxy)
(setq urlobj (url-generic-parse-url env-proxy))
(url-set-type urlobj "http")
(url-set-target urlobj nil))
;; Finally, fall back on the assumption that its just a hostname
(setq urlobj (url-generic-parse-url nil)) ; Get a blank object
(url-set-type urlobj "http")
(url-set-host urlobj env-proxy)))
(if (and (not cur-proxy) urlobj)
(setq url-proxy-services
(cons (cons scheme (format "%s:%d" (url-host urlobj)
(url-port urlobj)))
(message "Using a proxy for %s..." scheme)))))
(defun url-scheme-get-property (scheme property)
"Get property of a URL SCHEME.
Will automatically try to load a backend from url-SCHEME.el if
it has not already been loaded."
(setq scheme (downcase scheme))
(let ((desc (gethash scheme url-scheme-registry)))
(if (not desc)
(let* ((stub (concat "url-" scheme))
(loader (intern stub)))
(condition-case ()
(require loader)
(error nil))
(if (fboundp loader)
;; Found the module to handle <scheme> URLs
(url-scheme-register-proxy scheme)
(setq desc (list 'name scheme
'loader loader))
(dolist (cell url-scheme-methods)
(let ((symbol (intern-soft (format "%s-%s" stub (car cell))))
(type (cdr cell)))
(if symbol
(case type
;; Store the symbol name of a function
(if (fboundp symbol)
(setq desc (plist-put desc (car cell) symbol))))
;; Store the VALUE of a variable
(if (boundp symbol)
(setq desc (plist-put desc (car cell)
(symbol-value symbol)))))
(error "Malformed url-scheme-methods entry: %S"
(puthash scheme desc url-scheme-registry)))))
(or (plist-get desc property)
(plist-get url-scheme-default-properties property))))
(provide 'url-methods)