path: root/lisp/net/browse-url.el

;;; browse-url.el --- Pass a URL to a WWW browser

;; Copyright (C) 1995, 96, 97, 98, 99, 2000 Free Software Foundation, Inc.

;; Author: Denis Howe <dbh@doc.ic.ac.uk>
;; Maintainer: Dave Love <fx@gnu.org>
;; Created: 03 Apr 1995
;; Keywords: hypertext, hypermedia, mouse

;; 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
;; 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 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.

;;; Commentary:

;; This package provides functions which read a URL (Uniform Resource
;; Locator) from the minibuffer, defaulting to the URL around point,
;; and ask a World-Wide Web browser to load it.  It can also load the
;; URL associated with the current buffer.  Different browsers use
;; different methods of remote control so there is one function for
;; each supported browser.  If the chosen browser is not running, it
;; is started.  Currently there is support for the following browsers,
;; some of them probably now obsolete:

;; Function                           Browser     Earliest version
;; browse-url-netscape                Netscape    1.1b1
;; browse-url-mosaic                  XMosaic/mMosaic <= 2.4
;; browse-url-cci                     XMosaic     2.5
;; browse-url-w3                      w3          0
;; browse-url-w3-gnudoit              w3 remotely
;; browse-url-iximosaic               IXI Mosaic  ?
;; browse-url-lynx-*	              Lynx	     0
;; browse-url-grail                   Grail       0.3b1
;; browse-url-mmm                     MMM         ?
;; browse-url-generic                 arbitrary
;; browse-url-default-windows-browser MS-Windows browser

;; [A version of the Netscape browser is now free software
;; <URL:http://www.mozilla.org/>, albeit not GPLed, so it is
;; reasonable to have that as the default.]

;; Note that versions of Netscape before 1.1b1 did not have remote
;; control.  <URL:http://www.netscape.com/newsref/std/x-remote.html>.

;; Browsers can cache Web pages so it may be necessary to tell them to
;; reload the current page if it has changed (e.g. if you have edited
;; it).  There is currently no perfect automatic solution to this.

;; Netscape allows you to specify the id of the window you want to
;; control but which window DO you want to control and how do you
;; discover its id?

;; If using XMosaic before version 2.5, check the definition of
;; browse-url-usr1-signal below.
;; <URL:http://www.ncsa.uiuc.edu/SDG/Software/XMosaic/remote-control.html>

;; XMosaic version 2.5 introduced Common Client Interface allowing you
;; to control mosaic through Unix sockets.
;; <URL:http://www.ncsa.uiuc.edu/SDG/Software/XMosaic/CCI/cci-spec.html>

;; William M. Perry's excellent "w3" WWW browser for
;; Emacs <URL:ftp://cs.indiana.edu/pub/elisp/w3/>
;; has a function w3-follow-url-at-point, but that
;; doesn't let you edit the URL like browse-url.
;; The `gnuserv' package that can be used to control it in another
;; Emacs process is available from
;; <URL:ftp://ftp.splode.com/pub/users/friedman/packages/>.

;; Grail is the freely available WWW browser implemented in Python, a
;; cool object-oriented freely available interpreted language.  Grail
;; 0.3b1 was the first version to have remote control as distributed.
;; For more information on Grail see
;; <URL:http://grail.cnri.reston.va.us/> and for more information on
;; Python see <url:http://www.python.org/>.  Grail support in
;; browse-url.el written by Barry Warsaw <bwarsaw@python.org>.

;; MMM is a semi-free WWW browser implemented in Objective Caml, an
;; interesting impure functional programming language.  See
;; <URL:http://pauillac.inria.fr/%7Erouaix/mmm/>.

;; Lynx is now distributed by the FSF.  See also
;; <URL:http://lynx.browser.org/>.

;; Free graphical browsers that could be used by `browse-url-generic'
;; include Chimera <URL:ftp://ftp.cs.unlv.edu/pub/chimera> and
;; <URL:http://www.unlv.edu/chimera/>, Arena
;; <URL:ftp://ftp.yggdrasil.com/pub/dist/web/arena> and Amaya
;; <URL:ftp://ftp.w3.org/pub/amaya>.  mMosaic
;; <URL:ftp://sig.enst.fr/pub/multicast/mMosaic/>,
;; <URL:http://sig.enst.fr/~dauphin/mMosaic/> (with development
;; support for Java applets and multicast) can be used like Mosaic by
;; setting `browse-url-mosaic-program' appropriately.

;; I [Denis Howe, not Dave Love] recommend Nelson Minar
;; <nelson@santafe.edu>'s excellent html-helper-mode.el for editing
;; HTML and thank Nelson for his many useful comments on this code.
;; <URL:http://www.santafe.edu/%7Enelson/hhm-beta/>

;; See also hm--html-menus <URL:http://www.tnt.uni-hannover.de/%7Emuenkel/
;; software/own/hm--html-menus/>.  For composing correct HTML see also
;; PSGML the general SGML structure editor package
;; <URL:ftp://ftp.lysator.liu.se/pub/sgml>; hm--html-menus can be used
;; with this.

;; This package generalises function html-previewer-process in Marc
;; Andreessen's html-mode (LCD modes/html-mode.el.Z).  See also the
;; ffap.el package.  The huge hyperbole package also contains similar
;; functions.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Help!

;; Can you write and test some code for the Macintrash and Windoze
;; Netscape remote control APIs?  (See the URL above).

;; Do any other browsers have remote control?

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Usage

;; To display the URL at or before point:
;; M-x browse-url-at-point RET
;; or, similarly but with the opportunity to edit the URL extracted from
;; the buffer, use:
;; M-x browse-url

;; To display a URL by shift-clicking on it, put this in your ~/.emacs
;; file:
;;      (global-set-key [S-mouse-2] 'browse-url-at-mouse)
;; (Note that using Shift-mouse-1 is not desirable because
;; that event has a standard meaning in Emacs.)

;; To display the current buffer in a web browser:
;; M-x browse-url-of-buffer RET

;; To display the current region in a web browser:
;; M-x browse-url-of-region RET

;; In Dired, to display the file named on the current line:
;; M-x browse-url-of-dired-file RET

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Customisation (~/.emacs)

;; To see what variables are available for customization, type
;; `M-x set-variable browse-url TAB'.  Better, use
;; `M-x customize-group browse-url'.

;; Bind the browse-url commands to keys with the `C-c C-z' prefix
;; (as used by html-helper-mode):
;;	(global-set-key "\C-c\C-z." 'browse-url-at-point)
;;	(global-set-key "\C-c\C-zb" 'browse-url-of-buffer)
;;	(global-set-key "\C-c\C-zr" 'browse-url-of-region)
;;	(global-set-key "\C-c\C-zu" 'browse-url)
;;	(global-set-key "\C-c\C-zv" 'browse-url-of-file)
;;	(add-hook 'dired-mode-hook
;;		  (lambda ()
;;	             (local-set-key "\C-c\C-zf" 'browse-url-of-dired-file)))

;; Browse URLs in mail messages under RMAIL by clicking mouse-2:
;;	(add-hook 'rmail-mode-hook (lambda () ; rmail-mode startup
;;	  (define-key rmail-mode-map [mouse-2] 'browse-url-at-mouse)))
;; Alternatively, add `goto-address' to `rmail-show-message-hook'.

;; Gnus provides a standard feature to activate URLs in article
;; buffers for invocation of browse-url.

;; Use the Emacs w3 browser when not running under X11:
;;	(or (eq window-system 'x)
;;	    (setq browse-url-browser-function 'browse-url-w3))

;; To always save modified buffers before displaying the file in a browser:
;;	(setq browse-url-save-file t)

;; To get round the Netscape caching problem, you could EITHER have
;; write-file in html-helper-mode make Netscape reload the document:
;;
;;	(autoload 'browse-url-netscape-reload "browse-url"
;;	  "Ask a WWW browser to redisplay the current file." t)
;;	(add-hook 'html-helper-mode-hook
;;		  (lambda ()
;;		     (add-hook 'local-write-file-hooks
;;			       (lambda ()
;;				  (let ((local-write-file-hooks))
;;				    (save-buffer))
;;				  (browse-url-netscape-reload)
;;				  t)			; => file written by hook
;;			       t)))			; append to l-w-f-hooks
;;
;; OR have browse-url-of-file ask Netscape to load and then reload the
;; file:
;;
;;	(add-hook 'browse-url-of-file-hook 'browse-url-netscape-reload)

;; You may also want to customise browse-url-netscape-arguments, e.g.
;;	(setq browse-url-netscape-arguments '("-install"))
;;
;; or similarly for the other browsers.

;; To invoke different browsers for different URLs:
;;      (setq browse-url-browser-function '(("^mailto:" . browse-url-mail)
;;      				    ("." . browse-url-netscape)))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Code:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Variables

(eval-when-compile (require 'thingatpt)
                   (require 'term)
		   (require 'dired)
		   (require 'w3-auto nil t))

(defgroup browse-url nil
  "Use a web browser to look at a URL."
  :prefix "browse-url-"
  :link '(emacs-commentary-link "browse-url")
  :group 'hypermedia)

;;;###autoload
(defcustom browse-url-browser-function
  (if (eq system-type 'windows-nt)
      'browse-url-default-windows-browser
    'browse-url-netscape)
  "*Function to display the current buffer in a WWW browser.
This is used by the `browse-url-at-point', `browse-url-at-mouse', and
`browse-url-of-file' commands.

If the value is not a function it should be a list of pairs
\(REGEXP . FUNCTION).  In this case the function called will be the one
associated with the first REGEXP which matches the current URL.  The
function is passed the URL and any other args of `browse-url'.  The last
regexp should probably be \".\" to specify a default browser."
  :type '(choice
	  (function-item :tag "Emacs W3" :value  browse-url-w3)
	  (function-item :tag "W3 in another Emacs via `gnudoit'"
			 :value  browse-url-w3-gnudoit)
	  (function-item :tag "Netscape" :value  browse-url-netscape)
	  (function-item :tag "Mosaic" :value  browse-url-mosaic)
	  (function-item :tag "Mosaic using CCI" :value  browse-url-cci)
	  (function-item :tag "IXI Mosaic" :value  browse-url-iximosaic)
	  (function-item :tag "Lynx in an xterm window"
			 :value browse-url-lynx-xterm)
	  (function-item :tag "Lynx in an Emacs window"
			 :value browse-url-lynx-emacs)
	  (function-item :tag "Grail" :value  browse-url-grail)
	  (function-item :tag "MMM" :value  browse-url-mmm)
	  (function-item :tag "Specified by `Browse Url Generic Program'"
			 :value browse-url-generic)
	  (function-item :tag "Default Windows browser"
			 :value  browse-url-default-windows-browser)
	  (function :tag "Your own function")
	  (alist :tag "Regexp/function association list"
		 :key-type regexp :value-type function))
  :version "20.4"
  :group 'browse-url)

(defcustom browse-url-netscape-program "netscape"
  ;; Info about netscape-remote from Karl Berry.
  "The name by which to invoke Netscape.

The free program `netscape-remote' from
<URL:http://home.netscape.com/newsref/std/remote.c> is said to start
up very much quicker than `netscape'.  Reported to compile on a GNU
system, given vroot.h from the same directory, with cc flags
 -DSTANDALONE -L/usr/X11R6/lib -lXmu -lX11."
  :type 'string
  :group 'browse-url)

(defcustom browse-url-netscape-arguments nil
  "A list of strings to pass to Netscape as arguments."
  :type '(repeat (string :tag "Argument"))
  :group 'browse-url)

(defcustom browse-url-netscape-startup-arguments browse-url-netscape-arguments
  "A list of strings to pass to Netscape when it starts up.
Defaults to the value of `browse-url-netscape-arguments' at the time
`browse-url' is loaded."
  :type '(repeat (string :tag "Argument"))
  :group 'browse-url)

;;;###autoload
(defcustom browse-url-new-window-p nil
  "*If non-nil, always open a new browser window with appropriate browsers.
Passing an interactive argument to \\[browse-url], or specific browser
commands reverses the effect of this variable.  Requires Netscape version
1.1N or later or XMosaic version 2.5 or later if using those browsers."
  :type 'boolean
  :group 'browse-url)

;;;###autoload
(defcustom browse-url-netscape-display nil
  "*The X display for running Netscape, if not same as Emacs'."
  :type '(choice string (const :tag "Default" nil))
  :group 'browse-url)

(defcustom browse-url-mosaic-program "xmosaic"
  "The name by which to invoke Mosaic (or mMosaic)."
  :type 'string
  :version "20.3"
  :group 'browse-url)

(defcustom browse-url-mosaic-arguments nil
  "A list of strings to pass to Mosaic as arguments."
  :type '(repeat (string :tag "Argument"))
  :group 'browse-url)

(defcustom browse-url-filename-alist
  `(("^/\\(ftp@\\|anonymous@\\)?\\([^:]+\\):/*" . "ftp://\\2/")
    ;; The above loses the username to avoid the browser prompting for
    ;; it in anonymous cases.  If it's not anonymous the next regexp
    ;; applies.
    ("^/\\([^:@]+@\\)?\\([^:]+\\):/*" . "ftp://\\1\\2/")
    ,(if (memq system-type '(windows-nt ms-dos))
	  '("^\\([a-zA-Z]:\\)[\\/]" . "file:\\1/"))
    ("^/+" . "file:/"))
  "An alist of (REGEXP . STRING) pairs used by `browse-url-of-file'.
Any substring of a filename matching one of the REGEXPs is replaced by
the corresponding STRING using `replace-match', not treating STRING
literally.  All pairs are applied in the order given.  The default
value converts ange-ftp/EFS-style paths into ftp URLs and prepends
`file:' to any path beginning with `/'.

For example, adding to the default a specific translation of an ange-ftp
address to an HTTP URL:

    (setq browse-url-filename-alist
	  '((\"/webmaster@webserver:/home/www/html/\" .
	     \"http://www.acme.co.uk/\")
            (\"^/\\(ftp@\\|anonymous@\\)?\\([^:]+\\):/*\" . \"ftp://\\2/\")
            (\"^/\\([^:@]+@\\)?\\([^:]+\\):/*\" . \"ftp://\\1\\2/\")
	    (\"^/+\" . \"file:/\")))
"
  :type '(repeat (cons :format "%v"
                       (regexp :tag "Regexp")
                       (string :tag "Replacement")))
  :version "20.3"
  :group 'browse-url)

;;;###autoload
(defcustom browse-url-save-file nil
  "*If non-nil, save the buffer before displaying its file.
Used by the `browse-url-of-file' command."
  :type 'boolean
  :group 'browse-url)

(defcustom browse-url-of-file-hook nil
  "Run after `browse-url-of-file' has asked a browser to load a file.

Set this to `browse-url-netscape-reload' to force Netscape to load the
file rather than displaying a cached copy."
  :type 'hook
  :options '(browse-url-netscape-reload)
  :group 'browse-url)

(defvar browse-url-usr1-signal
  (if (and (boundp 'emacs-major-version)
	   (or (> emacs-major-version 19) (>= emacs-minor-version 29)))
      'SIGUSR1 ; Why did I think this was in lower case before?
    30)					; Check /usr/include/signal.h.
  "The argument to `signal-process' for sending SIGUSR1 to XMosaic.
Emacs 19.29 accepts 'SIGUSR1, earlier versions require an integer
which is 30 on SunOS and 16 on HP-UX and Solaris.")

(defcustom browse-url-CCI-port 3003
  "Port to access XMosaic via CCI.
This can be any number between 1024 and 65535 but must correspond to
the value set in the browser."
  :type 'integer
  :group 'browse-url)

(defcustom browse-url-CCI-host "localhost"
  "*Host to access XMosaic via CCI.
This should be the host name of the machine running XMosaic with CCI
enabled.  The port number should be set in `browse-url-CCI-port'."
  :type 'string
  :group 'browse-url)

(defvar browse-url-temp-file-name nil)
(make-variable-buffer-local 'browse-url-temp-file-name)

(defcustom browse-url-xterm-program "xterm"
  "The name of the terminal emulator used by `browse-url-lynx-xterm'.
This might, for instance, be a separate colour version of xterm."
  :type 'string
  :group 'browse-url)

(defcustom browse-url-xterm-args nil
  "*A list of strings defining options for `browse-url-xterm-program'.
These might set its size, for instance."
  :type '(repeat (string :tag "Argument"))
  :group 'browse-url)

(defcustom browse-url-lynx-emacs-args (and (not window-system) 
                                           '("-show_cursor"))
  "A list of strings defining options for Lynx in an Emacs buffer.

The default is none in a window system, otherwise `-show_cursor' to
indicate the position of the current link in the absence of
highlighting, assuming the normal default for showing the cursor."
  :type '(repeat (string :tag "Argument"))
  :version "20.3"
  :group 'browse-url)

(defcustom browse-url-gnudoit-program "gnudoit"
  "The name of the `gnudoit' program used by `browse-url-w3-gnudoit'."
  :type 'string
  :group 'browse-url)

(defcustom browse-url-gnudoit-args '("-q")
  "*A list of strings defining options for `browse-url-gnudoit-program'.
These might set the port, for instance."
  :type '(repeat (string :tag "Argument"))
  :group 'browse-url)

;;;###autoload
(defcustom browse-url-generic-program nil
  "*The name of the browser program used by `browse-url-generic'."
  :type '(choice string (const :tag "None" nil))
  :group 'browse-url)

(defcustom browse-url-generic-args nil
  "*A list of strings defining options for `browse-url-generic-program'."
  :type '(repeat (string :tag "Argument"))
  :group 'browse-url)

(defcustom browse-url-temp-dir temporary-file-directory
  "The name of a directory for browse-url's temporary files.
Such files are generated by functions like `browse-url-of-region'.
You might want to set this to somewhere with restricted read permissions
for privacy's sake."
  :type 'string
  :group 'browse-url)

(defcustom browse-url-netscape-version
  3
  "The version of Netscape you are using.
This affects how URL reloading is done; the mechanism changed
incompatibly at version 4."
  :type 'number
  :group 'browse-url)

(defcustom browse-url-lynx-input-field 'avoid
  "*Action on selecting an existing Lynx buffer at an input field.
What to do when sending a new URL to an existing Lynx buffer in Emacs
if the Lynx cursor is on an input field (in which case the `g' command
would be entered as data).  Such fields are recognized by the
underlines ____.  Allowed values: nil: disregard it, 'warn: warn the
user and don't emit the URL, 'avoid: try to avoid the field by moving
down (this *won't* always work)."
  :type '(choice (const :tag "Move to try to avoid field" :value avoid)
                 (const :tag "Disregard" :value nil)
                 (const :tag "Warn, don't emit URL" :value warn))
  :version "20.3"
  :group 'browse-url)

(defvar browse-url-lynx-input-attempts 10
  "*How many times to try to move down from a series of lynx input fields.")

(defcustom browse-url-lynx-input-delay 0.2
  "How many seconds to wait for lynx between moves down from an input field.")

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; URL input

(defun browse-url-url-at-point ()
  (let ((url (thing-at-point 'url)))
    (set-text-properties 0 (length url) nil url)
    url))

;; Having this as a separate function called by the browser-specific
;; functions allows them to be stand-alone commands, making it easier
;; to switch between browsers.

(defun browse-url-interactive-arg (prompt)
  "Read a URL from the minibuffer, prompting with PROMPT.
Default to the URL at or before point.  If invoked with a mouse button,
set point to the position clicked first.  Return a list for use in
`interactive' containing the URL and `browse-url-new-window-p' or its
negation if a prefix argument was given."
  (let ((event (elt (this-command-keys) 0)))
    (and (listp event) (mouse-set-point event)))
  (list (read-string prompt (browse-url-url-at-point))
	(not (eq (null browse-url-new-window-p)
		 (null current-prefix-arg)))))

;; interactive-p needs to be called at a function's top-level, hence
;; the macro.
(defmacro browse-url-maybe-new-window (arg)
  `(if (interactive-p)
       ,arg
     browse-url-new-window-p))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Browse current buffer

;;;###autoload
(defun browse-url-of-file (&optional file)
  "Ask a WWW browser to display FILE.
Display the current buffer's file if FILE is nil or if called
interactively.  Turn the filename into a URL with function
`browse-url-file-url'.  Pass the URL to a browser using the
`browse-url' function then run `browse-url-of-file-hook'."
  (interactive)
  (or file
      (setq file (buffer-file-name))
      (error "Current buffer has no file"))
  (let ((buf (get-file-buffer file)))
    (if buf
	(save-excursion
	  (set-buffer buf)
	  (cond ((not (buffer-modified-p)))
		(browse-url-save-file (save-buffer))
		(t (message "%s modified since last save" file))))))
  (browse-url (browse-url-file-url file))
  (run-hooks 'browse-url-of-file-hook))

(defun browse-url-file-url (file)
  "Return the URL corresponding to FILE.
Use variable `browse-url-filename-alist' to map filenames to URLs."
  ;; URL-encode special chars, do % first
  (let ((s 0))
    (while (setq s (string-match "%" file s))
      (setq file (replace-match "%25" t t file)
	    s (1+ s))))
  (while (string-match "[*\"()',=;? ]" file)
    (let ((enc (format "%%%x" (aref file (match-beginning 0)))))
      (setq file (replace-match enc t t file))))
  (let ((maps browse-url-filename-alist))
    (while maps
      (let* ((map (car maps))
	     (from-re (car map))
	     (to-string (cdr map)))
	(setq maps (cdr maps))
	(and (string-match from-re file)
	     (setq file (replace-match to-string t nil file))))))
  file)

;;;###autoload
(defun browse-url-of-buffer (&optional buffer)
  "Ask a WWW browser to display BUFFER.
Display the current buffer if BUFFER is nil.  Display only the
currently visible part of BUFFER (from a temporary file) if buffer is
narrowed."
  (interactive)
  (save-excursion
    (and buffer (set-buffer buffer))
    (let ((file-name
	   ;; Ignore real name if restricted
	   (and (= (- (point-max) (point-min)) (buffer-size))
		(or buffer-file-name
		    (and (boundp 'dired-directory) dired-directory)))))
      (or file-name
	  (progn
	    (or browse-url-temp-file-name
		(setq browse-url-temp-file-name
		      (convert-standard-filename
		       (make-temp-file
			(expand-file-name "burl" browse-url-temp-dir)))))
	    (setq file-name browse-url-temp-file-name)
	    (write-region (point-min) (point-max) file-name nil 'no-message)))
      (browse-url-of-file file-name))))

(defun browse-url-delete-temp-file (&optional temp-file-name)
  ;; Delete browse-url-temp-file-name from the file system
  ;; If optional arg TEMP-FILE-NAME is non-nil, delete it instead
  (let ((file-name (or temp-file-name browse-url-temp-file-name)))
    (if (and file-name (file-exists-p file-name))
	(delete-file file-name))))

(add-hook 'kill-buffer-hook 'browse-url-delete-temp-file)

;;;###autoload
(defun browse-url-of-dired-file ()
  "In Dired, ask a WWW browser to display the file named on this line."
  (interactive)
  (browse-url-of-file (dired-get-filename)))

;;;###autoload
(defun browse-url-of-region (min max)
  "Ask a WWW browser to display the current region."
  (interactive "r")
  (save-excursion
    (save-restriction
      (narrow-to-region min max)
      (browse-url-of-buffer))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Browser-independent commands

;; A generic command to call the current browse-url-browser-function

;;;###autoload
(defun browse-url (url &rest args)
  "Ask a WWW browser to load URL.
Prompts for a URL, defaulting to the URL at or before point.  Variable
`browse-url-browser-function' says which browser to use."
  (interactive (browse-url-interactive-arg "URL: "))
  (unless (interactive-p)
    (setq args (or args (list browse-url-new-window-p))))
  (if (functionp browse-url-browser-function)
      (apply browse-url-browser-function url args)
    ;; The `function' can be an alist; look down it for first match
    ;; and apply the function (which might be a lambda).
    (catch 'done
      (dolist (bf browse-url-browser-function)
	(when (string-match (car bf) url)
	  (apply (cdr bf) url args)
	  (throw 'done t)))
      (error "No browse-url-browser-function matching URL %s"
	     url))))

;;;###autoload
(defun browse-url-at-point (&optional arg)
  "Ask a WWW browser to load the URL at or before point.
Doesn't let you edit the URL like `browse-url'.  Variable
`browse-url-browser-function' says which browser to use."
  (interactive "P")
  (let ((url (browse-url-url-at-point)))
    (if url
	(browse-url url (if arg
			    (not browse-url-new-window-p)
			  browse-url-new-window-p))
      (error "No URL found"))))

;;;###autoload
(defun browse-url-at-mouse (event)
  "Ask a WWW browser to load a URL clicked with the mouse.
The URL is the one around or before the position of the mouse click
but point is not changed.  Doesn't let you edit the URL like
`browse-url'.  Variable `browse-url-browser-function' says which browser
to use."
  (interactive "e")
  (save-excursion
    (mouse-set-point event)
    (browse-url-at-point browse-url-new-window-p)))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Browser-specific commands

;; --- Default MS-Windows browser ---

(defun browse-url-default-windows-browser (url &optional new-window)
  (interactive (browse-url-interactive-arg "URL: "))
  (w32-shell-execute "open" url))

;; --- Netscape ---

(defun browse-url-process-environment ()
  "Set DISPLAY in the environment to the X display Netscape is running on.
This is either the value of variable `browse-url-netscape-display' if
non-nil, or the same display as Emacs if different from the current
environment, otherwise just use the current environment."
  (let ((display (or browse-url-netscape-display (browse-url-emacs-display))))
    (if display
	(cons (concat "DISPLAY=" display) process-environment)
      process-environment)))

(defun browse-url-emacs-display ()
  "Return the X display Emacs is running on.
This is nil if the display is the same as the DISPLAY environment variable.

Actually Emacs could be using several displays; this just returns the
one showing the selected frame."
  (let ((display (cdr-safe (assq 'display (frame-parameters)))))
    (and (not (equal display (getenv "DISPLAY")))
         display)))

;;;###autoload
(defun browse-url-netscape (url &optional new-window)
  "Ask the Netscape WWW browser to load URL.

Default to the URL around or before point.  The strings in variable
`browse-url-netscape-arguments' are also passed to Netscape.

When called interactively, if variable `browse-url-new-window-p' is
non-nil, load the document in a new Netscape window, otherwise use a
random existing one.  A non-nil interactive prefix argument reverses
the effect of `browse-url-new-window-p'.

When called non-interactively, optional second argument NEW-WINDOW is
used instead of `browse-url-new-window-p'."
  (interactive (browse-url-interactive-arg "Netscape URL: "))
  ;; URL encode any `confusing' characters in the URL.  This needs to
  ;; include at least commas; presumably also close parens.
  (while (string-match "[,)]" url)
    (setq url (replace-match
	       (format "%%%x" (string-to-char (match-string 0 url))) t t url)))
  (let* ((process-environment (browse-url-process-environment))
         (process (apply 'start-process
			 (concat "netscape " url) nil
			 browse-url-netscape-program
			 (append
			  browse-url-netscape-arguments
			  (if (eq window-system 'w32)
			      (list url)
			    (append
			     (if new-window '("-noraise"))
			     (list "-remote"
				   (concat "openURL(" url
					   (if (browse-url-maybe-new-window
						new-window)
					       ",new-window")
					   ")"))))))))
    (set-process-sentinel process
			  `(lambda (process change)
			     (browse-url-netscape-sentinel process ,url)))))

(defun browse-url-netscape-sentinel (process url)
  "Handle a change to the process communicating with Netscape."
  (or (eq (process-exit-status process) 0)
      (let* ((process-environment (browse-url-process-environment)))
	;; Netscape not running - start it
	(message "Starting Netscape...")
	(apply 'start-process (concat "netscape" url) nil
	       browse-url-netscape-program
	       (append browse-url-netscape-startup-arguments (list url))))))

(defun browse-url-netscape-reload ()
  "Ask Netscape to reload its current document.
How depends on `browse-url-netscape-version'."
  (interactive)
  ;; Backwards incompatibility reported by
  ;; <peter.kruse@psychologie.uni-regensburg.de>.
  (browse-url-netscape-send (if (>= browse-url-netscape-version 4)
				"xfeDoCommand(reload)"
				"reload")))

(defun browse-url-netscape-send (command)
  "Send a remote control command to Netscape."
  (let* ((process-environment (browse-url-process-environment)))
    (apply 'start-process "netscape" nil
           browse-url-netscape-program
           (append browse-url-netscape-arguments
                   (list "-remote" command)))))

;; --- Mosaic ---

;;;###autoload
(defun browse-url-mosaic (url &optional new-window)
  "Ask the XMosaic WWW browser to load URL.

Default to the URL around or before point.  The strings in variable
`browse-url-mosaic-arguments' are also passed to Mosaic and the
program is invoked according to the variable
`browse-url-mosaic-program'.

When called interactively, if variable `browse-url-new-window-p' is
non-nil, load the document in a new Mosaic window, otherwise use a
random existing one.  A non-nil interactive prefix argument reverses
the effect of `browse-url-new-window-p'.

When called non-interactively, optional second argument NEW-WINDOW is
used instead of `browse-url-new-window-p'."
  (interactive (browse-url-interactive-arg "Mosaic URL: "))
  (let ((pidfile (expand-file-name "~/.mosaicpid"))
	pid)
    (if (file-readable-p pidfile)
	(save-excursion
	  (find-file pidfile)
	  (goto-char (point-min))
	  (setq pid (read (current-buffer)))
	  (kill-buffer nil)))
    (if (and pid (zerop (signal-process pid 0))) ; Mosaic running
	(save-excursion
	  (find-file (format "/tmp/Mosaic.%d" pid))
	  (erase-buffer)
	  (insert (if (browse-url-maybe-new-window new-window)
		      "newwin\n"
		    "goto\n")
		  url "\n")
	  (save-buffer)
	  (kill-buffer nil)
	  ;; Send signal SIGUSR to Mosaic
	  (message "Signalling Mosaic...")
	  (signal-process pid browse-url-usr1-signal)
	  ;; Or you could try:
	  ;; (call-process "kill" nil 0 nil "-USR1" (int-to-string pid))
	  (message "Signalling Mosaic...done")
	  )
      ;; Mosaic not running - start it
      (message "Starting Mosaic...")
      (apply 'start-process "xmosaic" nil browse-url-mosaic-program
	     (append browse-url-mosaic-arguments (list url)))
      (message "Starting Mosaic...done"))))

;; --- Grail ---

;;;###autoload
(defvar browse-url-grail
  (concat (or (getenv "GRAILDIR") "~/.grail") "/user/rcgrail.py")
  "Location of Grail remote control client script `rcgrail.py'.
Typically found in $GRAILDIR/rcgrail.py, or ~/.grail/user/rcgrail.py.")

;;;###autoload
(defun browse-url-grail (url &optional new-window)
  "Ask the Grail WWW browser to load URL.
Default to the URL around or before point.  Runs the program in the
variable `browse-url-grail'."
  (interactive (browse-url-interactive-arg "Grail URL: "))
  (message "Sending URL to Grail...")
  (save-excursion
    (set-buffer (get-buffer-create " *Shell Command Output*"))
    (erase-buffer)
    ;; don't worry about this failing.
    (if new-window
	(call-process browse-url-grail nil 0 nil "-b" url)
      (call-process browse-url-grail nil 0 nil url))
    (message "Sending URL to Grail... done")))

;; --- Mosaic using CCI ---

;;;###autoload
(defun browse-url-cci (url &optional new-window)
  "Ask the XMosaic WWW browser to load URL.
Default to the URL around or before point.

This function only works for XMosaic version 2.5 or later.  You must
select `CCI' from XMosaic's File menu, set the CCI Port Address to the
value of variable `browse-url-CCI-port', and enable `Accept requests'.

When called interactively, if variable `browse-url-new-window-p' is
non-nil, load the document in a new browser window, otherwise use a
random existing one.  A non-nil interactive prefix argument reverses
the effect of `browse-url-new-window-p'.

When called non-interactively, optional second argument NEW-WINDOW is
used instead of `browse-url-new-window-p'."
  (interactive (browse-url-interactive-arg "Mosaic URL: "))
  (open-network-stream "browse-url" " *browse-url*"
		       browse-url-CCI-host browse-url-CCI-port)
  ;; Todo: start browser if fails
  (process-send-string "browse-url"
		       (concat "get url (" url ") output "
			       (if (browse-url-maybe-new-window new-window)
				   "new"
				 "current")
			       "\r\n"))
  (process-send-string "browse-url" "disconnect\r\n")
  (delete-process "browse-url"))

;; --- IXI Mosaic ---

;;;###autoload
(defun browse-url-iximosaic (url &optional new-window)
  ;; new-window ignored
  "Ask the IXIMosaic WWW browser to load URL.
Default to the URL around or before point."
  (interactive (browse-url-interactive-arg "IXI Mosaic URL: "))
  (start-process "tellw3b" nil "tellw3b"
		 "-service WWW_BROWSER ixi_showurl " url))

;; --- W3 ---

;;;###autoload
(defun browse-url-w3 (url &optional new-window)
  "Ask the w3 WWW browser to load URL.
Default to the URL around or before point.

When called interactively, if variable `browse-url-new-window-p' is
non-nil, load the document in a new window.  A non-nil interactive
prefix argument reverses the effect of `browse-url-new-window-p'.

When called non-interactively, optional second argument NEW-WINDOW is
used instead of `browse-url-new-window-p'."
  (interactive (browse-url-interactive-arg "W3 URL: "))
  (require 'w3)				; w3-fetch-other-window not autoloaded
  (if (browse-url-maybe-new-window new-window)
      (w3-fetch-other-window url)
    (w3-fetch url)))

;;;###autoload
(defun browse-url-w3-gnudoit (url &optional new-window)
  ;; new-window ignored
  "Ask another Emacs running gnuserv to load the URL using the W3 browser.
The `browse-url-gnudoit-program' program is used with options given by
`browse-url-gnudoit-args'.  Default to the URL around or before point."
  (interactive (browse-url-interactive-arg "W3 URL: "))
    (apply 'start-process (concat "gnudoit:" url) nil
	   browse-url-gnudoit-program
	   (append browse-url-gnudoit-args
		   (list (concat "(w3-fetch \"" url "\")")
			 "(raise-frame)"))))

;; --- Lynx in an xterm ---

;;;###autoload
(defun browse-url-lynx-xterm (url &optional new-window)
  ;; new-window ignored
  "Ask the Lynx WWW browser to load URL.
Default to the URL around or before point.  A new Lynx process is run
in an Xterm window using the Xterm program named by `browse-url-xterm-program'
with possible additional arguments `browse-url-xterm-args'."
  (interactive (browse-url-interactive-arg "Lynx URL: "))
  (apply #'start-process `(,(concat "lynx" url) nil ,browse-url-xterm-program
             ,@browse-url-xterm-args "-e" "lynx"
	     ,url)))

;; --- Lynx in an Emacs "term" window ---

;;;###autoload
(defun browse-url-lynx-emacs (url &optional new-buffer)
  "Ask the Lynx WWW browser to load URL.
Default to the URL around or before point.  With a prefix argument, run
a new Lynx process in a new buffer.

When called interactively, if variable `browse-url-new-window-p' is
non-nil, load the document in a new lynx in a new term window,
otherwise use any existing one.  A non-nil interactive prefix argument
reverses the effect of `browse-url-new-window-p'.

When called non-interactively, optional second argument NEW-WINDOW is
used instead of `browse-url-new-window-p'."
  (interactive (browse-url-interactive-arg "Lynx URL: "))
  (let* ((system-uses-terminfo t)       ; Lynx uses terminfo
	 ;; (term-term-name "vt100") ; ??
	 (buf (get-buffer "*lynx*"))
	 (proc (and buf (get-buffer-process buf)))
	 (n browse-url-lynx-input-attempts))
    (if (and (browse-url-maybe-new-window new-buffer) buf)
	;; Rename away the OLD buffer. This isn't very polite, but
	;; term insists on working in a buffer named *lynx* and would
	;; choke on *lynx*<1>
	(progn (set-buffer buf)
	       (rename-uniquely)))
    (if (or (browse-url-maybe-new-window new-buffer)
	    (not buf)
	    (not proc)
	    (not (memq (process-status proc) '(run stop))))
	;; start a new lynx
	(progn
          (setq buf
                (apply #'make-term
                       `("lynx" "lynx" nil ,@browse-url-lynx-emacs-args
			 ,url)))
          (switch-to-buffer buf)
          (term-char-mode)
          (set-process-sentinel
           (get-buffer-process buf)
           ;; Don't leave around a dead one (especially because of its
           ;; munged keymap.)
           (lambda (process event)
             (if (not (memq (process-status process) '(run stop)))
                 (let ((buf (process-buffer process)))
                   (if buf (kill-buffer buf)))))))
      ;; send the url to lynx in the old buffer
      (let ((win (get-buffer-window buf t)))
	(if win
	    (select-window win)
	  (switch-to-buffer buf)))
      (if (eq (following-char) ?_)
	  (cond ((eq browse-url-lynx-input-field 'warn)
		 (error "Please move out of the input field first."))
		((eq browse-url-lynx-input-field 'avoid)
		 (while (and (eq (following-char) ?_) (> n 0))
		   (term-send-down) ; down arrow
		   (sit-for browse-url-lynx-input-delay))
		 (if (eq (following-char) ?_)
		     (error "Cannot move out of the input field, sorry.")))))
      (term-send-string proc (concat "g" ; goto
				     "\C-u" ; kill default url
				     url
				     "\r")))))

;; --- MMM ---

;;;###autoload
(defun browse-url-mmm (url &optional new-window)
  "Ask the MMM WWW browser to load URL.
Default to the URL around or before point."
  (interactive (browse-url-interactive-arg "MMM URL: "))
  (message "Sending URL to MMM...")
  (save-excursion
    (set-buffer (get-buffer-create " *Shell Command Output*"))
    (erase-buffer)
    ;; mmm_remote just SEGVs if the file isn't there...
    (if (or (file-exists-p (expand-file-name "~/.mmm_remote"))
	    ;; location in v 0.4:
	    (file-exists-p (expand-file-name "~/.mmm/remote")))
	(call-process "mmm_remote" nil 0 nil url)
      (call-process "mmm" nil 0 nil "-external" url))
    (message "Sending URL to MMM... done")))

;; --- mailto ---

;;;###autoload
(defun browse-url-mail (url &optional new-window)
  "Open a new mail message buffer within Emacs.
Default to using the mailto: URL around or before point as the
recipient's address.  Supplying a non-nil interactive prefix argument
will cause the mail to be composed in another window rather than the
current one.

When called interactively, if variable `browse-url-new-window-p' is
non-nil use `compose-mail-other-window', otherwise `compose-mail'.  A
non-nil interactive prefix argument reverses the effect of
`browse-url-new-window-p'.

When called non-interactively, optional second argument NEW-WINDOW is
used instead of `browse-url-new-window-p'."
  (interactive (browse-url-interactive-arg "Mailto URL: "))
  (save-excursion
    (let ((to (if (string-match "^mailto:" url)
		  (substring url 7)
		url)))
      (if (browse-url-maybe-new-window new-window)
	  (compose-mail-other-window to nil nil nil
				     (list 'insert-buffer (current-buffer)))
	(compose-mail to nil nil nil nil
		      (list 'insert-buffer (current-buffer)))))))

;; --- Random browser ---

;;;###autoload
(defun browse-url-generic (url &optional new-window)
  ;; new-window ignored
  "Ask the WWW browser defined by `browse-url-generic-program' to load URL.
Default to the URL around or before point.  A fresh copy of the
browser is started up in a new process with possible additional arguments
`browse-url-generic-args'.  This is appropriate for browsers which
don't offer a form of remote control."
  (interactive (browse-url-interactive-arg "URL: "))
  (if (not browse-url-generic-program)
    (error "No browser defined (`browse-url-generic-program')"))
  (apply 'start-process (concat browse-url-generic-program url) nil
	 browse-url-generic-program
	 (append browse-url-generic-args (list url))))

(provide 'browse-url)

;;; browse-url.el ends here