1 ;;; elpher.el --- A friendly gopher and gemini client -*- lexical-binding: t -*-
3 ;; Copyright (C) 2021 Jens Östlund <jostlund@gmail.com>
4 ;; Copyright (C) 2021 F. Jason Park <jp@neverwas.me>
5 ;; Copyright (C) 2021 Christopher Brannon <chris@the-brannons.com>
6 ;; Copyright (C) 2021 Omar Polo <op@omarpolo.com>
7 ;; Copyright (C) 2021 Noodles! <nnoodle@chiru.no>
8 ;; Copyright (C) 2021 Abhiseck Paira <abhiseckpaira@disroot.org>
9 ;; Copyright (C) 2020-2021 Alex Schroeder <alex@gnu.org>
10 ;; Copyright (C) 2020 Zhiwei Chen <chenzhiwei03@kuaishou.com>
11 ;; Copyright (C) 2020 condy0919 <condy0919@gmail.com>
12 ;; Copyright (C) 2020 Alexis <flexibeast@gmail.com>
13 ;; Copyright (C) 2020 Étienne Deparis <etienne@depar.is>
14 ;; Copyright (C) 2020 Simon Nicolussi <sinic@sinic.name>
15 ;; Copyright (C) 2020 Michel Alexandre Salim <michel@michel-slm.name>
16 ;; Copyright (C) 2020 Koushk Roy <kroy@twilio.com>
17 ;; Copyright (C) 2020 Vee <vee@vnsf.xyz>
18 ;; Copyright (C) 2020 Simon South <simon@simonsouth.net>
19 ;; Copyright (C) 2019-2021 Tim Vaughan <plugd@thelambdalab.xyz>
21 ;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
22 ;; Created: 11 April 2019
24 ;; Keywords: comm gopher
25 ;; Homepage: https://thelambdalab.xyz/elpher
26 ;; Package-Requires: ((emacs "27.1"))
28 ;; This file is not part of GNU Emacs.
30 ;; This program is free software: you can redistribute it and/or modify
31 ;; it under the terms of the GNU General Public License as published by
32 ;; the Free Software Foundation, either version 3 of the License, or
33 ;; (at your option) any later version.
35 ;; This program is distributed in the hope that it will be useful,
36 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
37 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
38 ;; GNU General Public License for more details.
40 ;; You should have received a copy of the GNU General Public License
41 ;; along with this file. If not, see <http://www.gnu.org/licenses/>.
45 ;; Elpher aims to provide a practical and friendly gopher and gemini
46 ;; client for GNU Emacs. It supports:
48 ;; - intuitive keyboard and mouse-driven browsing,
49 ;; - out-of-the-box compatibility with evil-mode,
50 ;; - clickable web and gopher links *in plain text*,
51 ;; - caching of visited sites,
52 ;; - pleasant and configurable colouring of Gopher directories,
53 ;; - direct visualisation of image files,
54 ;; - gopher connections using TLS encryption,
55 ;; - the fledgling Gemini protocol,
56 ;; - the greybeard Finger protocol.
58 ;; To launch Elpher, simply use 'M-x elpher'. This will open a start
59 ;; page containing information on key bindings and suggested starting
60 ;; points for your gopher exploration.
62 ;; Full instructions can be found in the Elpher info manual.
64 ;; Elpher is under active development. Any suggestions for
65 ;; improvements are welcome, and can be made on the official project
66 ;; page, gopher://thelambdalab.xyz/1/projects/elpher, or via the
67 ;; project mailing list at https://lists.sr.ht/~michel-slm/elpher.
88 (defconst elpher-version "3.2.0"
89 "Current version of elpher.")
91 (defconst elpher-margin-width 6
92 "Width of left-hand margin used when rendering indicies.")
94 (defconst elpher-type-map
95 '(((gopher ?0) elpher-get-gopher-page elpher-render-text "txt" elpher-text)
96 ((gopher ?1) elpher-get-gopher-page elpher-render-index "/" elpher-index)
97 ((gopher ?4) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
98 ((gopher ?5) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
99 ((gopher ?7) elpher-get-gopher-query-page elpher-render-index "?" elpher-search)
100 ((gopher ?9) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
101 ((gopher ?g) elpher-get-gopher-page elpher-render-image "img" elpher-image)
102 ((gopher ?p) elpher-get-gopher-page elpher-render-image "img" elpher-image)
103 ((gopher ?I) elpher-get-gopher-page elpher-render-image "img" elpher-image)
104 ((gopher ?d) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
105 ((gopher ?P) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
106 ((gopher ?s) elpher-get-gopher-page elpher-render-download "snd" elpher-binary)
107 ((gopher ?h) elpher-get-gopher-page elpher-render-html "htm" elpher-html)
108 (gemini elpher-get-gemini-page elpher-render-gemini "gem" elpher-gemini)
109 (finger elpher-get-finger-page elpher-render-text "txt" elpher-text)
110 (telnet elpher-get-telnet-page nil "tel" elpher-telnet)
111 (other-url elpher-get-other-url-page nil "url" elpher-other-url)
112 (file elpher-get-file-page nil "~" elpher-gemini)
113 ((about welcome) elpher-get-welcome-page nil "E" elpher-index)
114 ((about bookmarks) elpher-get-bookmarks-page nil "E" elpher-index)
115 ((about history) elpher-get-history-page nil "E" elpher-index)
116 ((about visited-pages) elpher-get-visited-pages-page nil "E" elpher-index))
117 "Association list from types to getters, renderers, margin codes and index faces.")
120 ;;; Declarations to avoid compiler warnings.
124 (declare-function ansi-color-filter-apply "ansi-color")
125 (declare-function ansi-color-apply "ansi-color")
126 (declare-function bookmark-store "bookmark")
127 (declare-function org-link-store-props "ol")
128 (declare-function org-link-set-parameters "ol")
129 (defvar ansi-color-context)
130 (defvar bookmark-make-record-function)
131 (defvar mu4e~view-beginning-of-url-regexp)
132 (defvar eww-use-browse-url)
133 (defvar thing-at-point-uri-schemes)
134 (defvar xterm-color-preserve-properties))
137 ;;; Customization group
141 "A gopher and gemini client."
142 :group 'applications)
144 ;; General appearance and customizations
146 (defcustom elpher-open-urls-with-eww nil
147 "If non-nil, open URL selectors using eww.
148 Otherwise, use the system browser via the `browse-url' function."
151 (defcustom elpher-use-header t
152 "If non-nil, display current page information in buffer header."
155 (defcustom elpher-auto-disengage-TLS nil
156 "If non-nil, automatically disengage TLS following an unsuccessful connection.
157 While enabling this may seem convenient, it is also potentially
158 dangerous as it allows switching from an encrypted channel back to
159 plain text without user input."
162 (defcustom elpher-connection-timeout 5
163 "Specifies the number of seconds to wait for a network connection to time out."
166 (defcustom elpher-filter-ansi-from-text nil
167 "If non-nil, filter ANSI escape sequences from text.
168 The default behaviour is to use the ansi-color package to interpret these
172 (defcustom elpher-certificate-directory
173 (file-name-as-directory (locate-user-emacs-file "elpher-certificates"))
174 "Specify the name of the directory where client certificates will be stored.
175 These certificates may be used for establishing authenticated TLS connections."
178 (defcustom elpher-openssl-command "openssl"
179 "The command used to launch openssl when generating TLS client certificates."
182 (defcustom elpher-default-url-type "gopher"
183 "Default URL type (i.e. scheme) to assume if not explicitly given."
184 :type '(choice (const "gopher")
187 (defcustom elpher-gemini-TLS-cert-checks nil
188 "If non-nil, verify gemini server TLS certs using the default security level.
189 Otherwise, certificate verification is disabled.
191 This defaults to off because it is standard practice for Gemini servers
192 to use self-signed certificates, meaning that most servers provide what
193 EMACS considers to be an invalid certificate."
196 (defcustom elpher-gemini-max-fill-width 80
197 "Specify the maximum default width (in columns) of text/gemini documents.
198 The actual width used is the minimum of this value and the window width at
199 the time when the text is rendered."
202 (defcustom elpher-gemini-link-string "→ "
203 "Specify the string used to indicate links when rendering gemini maps.
207 (defcustom elpher-gemini-bullet-string "•"
208 "Specify the string used for bullets when rendering gemini maps."
211 (defcustom elpher-ipv4-always nil
212 "If non-nil, elpher will always use IPv4 to establish network connections.
213 This can be useful when browsing from a computer that supports IPv6, because
214 some servers which do not support IPv6 can take a long time to time-out."
217 (defcustom elpher-socks-always nil
218 "If non-nil, elpher will establish network connections over a SOCKS proxy.
219 Otherwise, the SOCKS proxy is only used for connections to onion services."
222 (defcustom elpher-use-emacs-bookmark-menu nil
223 "If non-nil, elpher will only use the native Emacs bookmark menu.
224 Otherwise, \\[elpher-show-bookmarks] will visit a special elpher bookmark
225 page within which all of the standard elpher keybindings are active."
228 (defcustom elpher-start-page "about:welcome"
229 "Specify the page displayed initially by elpher.
230 The default welcome screen is \"about:welcome\", while the bookmarks list
231 is \"about:bookmarks\". You can also specify local files via \"file:\".
233 Beware that using \"about:bookmarks\" as a start page in combination with
234 the `elpher-use-bookmark-menu' variable set to non-nil will prevent the
235 Emacs bookmark menu being accessible via \\[elpher-show-bookmarks] from
239 ;; Face customizations
241 (defgroup elpher-faces nil
242 "Elpher face customizations."
245 (defface elpher-index
246 '((t :inherit font-lock-keyword-face))
247 "Face used for directory type directory records.")
251 "Face used for text type directory records.")
254 '((t :inherit default))
255 "Face used for info type directory records.")
257 (defface elpher-image
258 '((t :inherit font-lock-string-face))
259 "Face used for image type directory records.")
261 (defface elpher-search
262 '((t :inherit warning))
263 "Face used for search type directory records.")
266 '((t :inherit font-lock-comment-face))
267 "Face used for html type directory records.")
269 (defface elpher-gemini
270 '((t :inherit font-lock-constant-face))
271 "Face used for Gemini type directory records.")
273 (defface elpher-other-url
274 '((t :inherit font-lock-comment-face))
275 "Face used for other URL type links records.")
277 (defface elpher-telnet
278 '((t :inherit font-lock-function-name-face))
279 "Face used for telnet type directory records.")
281 (defface elpher-binary
282 '((t :inherit font-lock-doc-face))
283 "Face used for binary type directory records.")
285 (defface elpher-unknown
286 '((t :inherit error))
287 "Face used for directory records with unknown/unsupported types.")
289 (defface elpher-margin-key
291 "Face used for directory margin key.")
293 (defface elpher-margin-brackets
294 '((t :inherit shadow))
295 "Face used for brackets around directory margin key.")
297 (defface elpher-gemini-heading1
298 '((t :inherit bold :height 1.8))
299 "Face used for gemini heading level 1.")
301 (defface elpher-gemini-heading2
302 '((t :inherit bold :height 1.5))
303 "Face used for gemini heading level 2.")
305 (defface elpher-gemini-heading3
306 '((t :inherit bold :height 1.2))
307 "Face used for gemini heading level 3.")
309 (defface elpher-gemini-preformatted
310 '((t :inherit fixed-pitch))
311 "Face used for pre-formatted gemini text blocks.")
313 (defface elpher-gemini-quoted
314 '((t :inherit font-lock-doc-face))
315 "Face used for gemini quoted texts.")
322 ;; An elpher "address" object is either a url object or a symbol.
323 ;; Addresses with the "about" type, corresponding to pages generated
324 ;; dynamically for and by elpher. All others represent pages which
325 ;; rely on content retrieved over the network.
327 (defun elpher-address-from-url (url-string)
328 "Create a ADDRESS object corresponding to the given URL-STRING."
329 (let ((data (match-data))) ; Prevent parsing clobbering match data
331 (let ((url (url-generic-parse-url url-string)))
332 (unless (and (not (url-fullness url)) (url-type url))
333 (setf (url-fullness url) t)
334 (unless (url-type url)
335 (setf (url-type url) elpher-default-url-type))
336 (unless (url-host url)
337 (let ((p (split-string (url-filename url) "/" nil nil)))
338 (setf (url-host url) (car p))
339 (setf (url-filename url)
341 (concat "/" (mapconcat #'identity (cdr p) "/"))
343 (when (or (equal "gopher" (url-type url))
344 (equal "gophers" (url-type url)))
346 (when (or (equal (url-filename url) "")
347 (equal (url-filename url) "/"))
348 (setf (url-filename url) "/1")))
349 (when (equal "gemini" (url-type url))
351 (if (equal (url-filename url) "")
352 (setf (url-filename url) "/"))))
353 (elpher-remove-redundant-ports url))
354 (set-match-data data))))
356 (defun elpher-remove-redundant-ports (address)
357 "Remove redundant port specifiers from ADDRESS.
358 Here 'redundant' means that the specified port matches the default
359 for that protocol, eg 70 for gopher."
360 (if (and (not (elpher-address-about-p address))
361 (eq (url-portspec address) ; (url-port) is too slow!
362 (pcase (url-type address)
364 ((or "gopher" "gophers") 70)
367 (setf (url-portspec address) nil))
370 (defun elpher-make-gopher-address (type selector host port &optional tls)
371 "Create an ADDRESS object using gopher directory record attributes.
372 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
373 If the optional attribute TLS is non-nil, the address will be marked as
374 requiring gopher-over-TLS."
376 ((equal type ?i) nil)
377 ((and (equal type ?h)
378 (string-prefix-p "URL:" selector))
379 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
381 (elpher-address-from-url
384 ":" (number-to-string port))))
386 (elpher-address-from-url
387 (concat "gopher" (if tls "s" "")
389 ":" (number-to-string port)
393 (defun elpher-make-about-address (type)
394 "Create an ADDRESS object corresponding to the given about address TYPE."
395 (elpher-address-from-url (concat "about:" (symbol-name type))))
397 (defun elpher-address-to-url (address)
398 "Get string representation of ADDRESS."
399 (url-encode-url (url-recreate-url address)))
401 (defun elpher-address-type (address)
402 "Retrieve type of ADDRESS object.
403 This is used to determine how to retrieve and render the document the
404 address refers to, via the table `elpher-type-map'."
405 (pcase (url-type address)
407 (list 'about (intern (url-filename address))))
408 ((or "gopher" "gophers")
410 (if (member (url-filename address) '("" "/"))
412 (string-to-char (substring (url-filename address) 1)))))
419 (defun elpher-address-about-p (address)
420 "Return non-nil if ADDRESS is an about address."
421 (pcase (elpher-address-type address) (`(about ,_) t)))
423 (defun elpher-address-gopher-p (address)
424 "Return non-nill if ADDRESS object is a gopher address."
425 (eq 'gopher (elpher-address-type address)))
427 (defun elpher-address-protocol (address)
428 "Retrieve the transport protocol for ADDRESS."
431 (defun elpher-address-filename (address)
432 "Retrieve the filename component of ADDRESS.
433 For gopher addresses this is a combination of the selector type and selector."
434 (url-unhex-string (url-filename address)))
436 (defun elpher-address-host (address)
437 "Retrieve host from ADDRESS object."
440 (defun elpher-address-user (address)
441 "Retrieve user from ADDRESS object."
444 (defun elpher-address-port (address)
445 "Retrieve port from ADDRESS object.
446 If no address is defined, returns 0. (This is for compatibility with the URL library.)"
449 (defun elpher-gopher-address-selector (address)
450 "Retrieve gopher selector from ADDRESS object."
451 (if (member (url-filename address) '("" "/"))
453 (url-unhex-string (substring (url-filename address) 2))))
458 (defvar elpher-content-cache (make-hash-table :test 'equal))
459 (defvar elpher-pos-cache (make-hash-table :test 'equal))
461 (defun elpher-get-cached-content (address)
462 "Retrieve the cached content for ADDRESS, or nil if none exists."
463 (gethash address elpher-content-cache))
465 (defun elpher-cache-content (address content)
466 "Set the content cache for ADDRESS to CONTENT."
467 (puthash address content elpher-content-cache))
469 (defun elpher-get-cached-pos (address)
470 "Retrieve the cached cursor position for ADDRESS, or nil if none exists."
471 (gethash address elpher-pos-cache))
473 (defun elpher-cache-pos (address pos)
474 "Set the cursor position cache for ADDRESS to POS."
475 (puthash address pos elpher-pos-cache))
480 (defun elpher-make-page (display-string address)
481 "Create a page with DISPLAY-STRING and ADDRESS."
482 (list display-string address))
484 (defun elpher-make-start-page ()
485 "Create the welcome page."
486 (elpher-make-page "Start Page"
487 (elpher-address-from-url elpher-start-page)))
489 (defun elpher-page-display-string (page)
490 "Retrieve the display string corresponding to PAGE."
493 (defun elpher-page-address (page)
494 "Retrieve the address corresponding to PAGE."
497 (defun elpher-page-set-address (page new-address)
498 "Set the address corresponding to PAGE to NEW-ADDRESS."
499 (setcar (cdr page) new-address))
501 (defvar elpher-current-page nil
502 "The current page for this Elpher buffer.")
504 (defvar elpher-history nil
505 "The local history stack for this Elpher buffer.
506 This variable is used by `elpher-back' and
507 `elpher-show-history'.")
509 (defvar elpher-visited-pages nil
510 "The global history for all Elpher buffers.
511 This variable is used by `elpher-show-visited-pages'.")
513 (defun elpher-visit-page (page &optional renderer no-history)
514 "Visit PAGE using its own renderer or RENDERER, if non-nil.
515 Additionally, push PAGE onto the history stack and the list of
516 previously-visited pages,unless NO-HISTORY is non-nil."
518 (elpher-process-cleanup)
520 (unless (or (not elpher-current-page)
521 (equal (elpher-page-address elpher-current-page)
522 (elpher-page-address page)))
523 (push elpher-current-page elpher-history)
524 (unless (or (elpher-address-about-p (elpher-page-address page))
525 (and elpher-visited-pages
526 (equal page (car elpher-visited-pages))))
527 (push page elpher-visited-pages))))
528 (setq-local elpher-current-page page)
529 (let* ((address (elpher-page-address page))
530 (type (elpher-address-type address))
531 (type-record (cdr (assoc type elpher-type-map))))
533 (funcall (car type-record)
537 (elpher-visit-previous-page)
539 (`(gopher ,type-char)
540 (error "Unsupported gopher selector type '%c' for '%s'"
541 type-char (elpher-address-to-url address)))
543 (error "Unsupported address type '%S' for '%s'"
544 other (elpher-address-to-url address)))))))
546 (defun elpher-visit-previous-page ()
547 "Visit the previous page in the history."
549 (elpher-visit-page (pop elpher-history) nil t)
550 (error "No previous page")))
552 (defun elpher-reload-current-page ()
553 "Reload the current page, discarding any existing cached content."
554 (elpher-cache-content (elpher-page-address elpher-current-page) nil)
555 (elpher-visit-page elpher-current-page))
557 (defun elpher-save-pos ()
558 "Save the current position of point to the current page."
559 (when elpher-current-page
560 (elpher-cache-pos (elpher-page-address elpher-current-page) (point))))
562 (defun elpher-restore-pos ()
563 "Restore the position of point to that cached in the current page."
564 (let ((pos (elpher-get-cached-pos (elpher-page-address elpher-current-page))))
567 (goto-char (point-min)))))
570 ;;; Buffer preparation
573 (defvar elpher-buffer-name "*elpher*"
574 "The default name of the Elpher buffer.")
576 (defun elpher-update-header ()
577 "If `elpher-use-header' is true, display current page info in window header."
578 (if elpher-use-header
579 (let* ((display-string (elpher-page-display-string elpher-current-page))
580 (address (elpher-page-address elpher-current-page))
581 (tls-string (if (and (not (elpher-address-about-p address))
582 (member (elpher-address-protocol address)
583 '("gophers" "gemini")))
586 (header (concat display-string
587 (propertize tls-string 'face 'bold))))
588 (setq header-line-format header))))
590 (defmacro elpher-with-clean-buffer (&rest args)
591 "Evaluate ARGS with a clean *elpher* buffer as current."
592 (declare (debug (body))) ;; Allow edebug to step through body
593 `(with-current-buffer elpher-buffer-name
594 (unless (eq major-mode 'elpher-mode)
595 ;; avoid resetting buffer-local variables
597 (let ((inhibit-read-only t)
598 (ansi-color-context nil)) ;; clean ansi interpreter state
599 (setq-local network-security-level
600 (default-value 'network-security-level))
602 (elpher-update-header)
605 (defun elpher-buffer-message (string &optional line)
606 "Replace first line in elpher buffer with STRING.
607 If LINE is non-nil, replace that line instead."
608 (with-current-buffer elpher-buffer-name
609 (let ((inhibit-read-only t))
610 (goto-char (point-min))
613 (let ((data (match-data)))
616 (re-search-forward "^.*$")
617 (replace-match string))
618 (set-match-data data))))))
624 (defvar elpher-user-coding-system nil
625 "User-specified coding system to use for decoding text responses.")
627 (defun elpher-decode (string)
628 "Decode STRING using autodetected or user-specified coding system."
629 (decode-coding-string string
630 (if elpher-user-coding-system
631 elpher-user-coding-system
632 (detect-coding-string string t))))
634 (defun elpher-preprocess-text-response (string)
635 "Preprocess text selector response contained in STRING.
636 This involes decoding the character representation, and clearing
637 away CRs and any terminating period."
638 (elpher-decode (replace-regexp-in-string "\n\\.\n$" "\n"
639 (replace-regexp-in-string "\r" "" string))))
643 (defconst elpher-url-regex
644 "\\([a-zA-Z]+\\)://\\([a-zA-Z0-9.-]*[a-zA-Z0-9-]\\|\\[[a-zA-Z0-9:]+\\]\\)\\(:[0-9]+\\)?\\(/\\([0-9a-zA-Z_~?/@|:.%#=&-]*[0-9a-zA-Z_~?/@|#-]\\)?\\)?"
645 "Regexp used to locate and buttonify URLs in text files loaded by elpher.")
647 (defun elpher-buttonify-urls (string)
648 "Turn substrings which look like urls in STRING into clickable buttons."
651 (goto-char (point-min))
652 (while (re-search-forward elpher-url-regex nil t)
653 (let ((page (elpher-make-page (substring-no-properties (match-string 0))
654 (elpher-address-from-url (match-string 0)))))
655 (make-text-button (match-beginning 0)
658 'action #'elpher-click-link
660 'help-echo #'elpher--page-button-help
664 ;;; ANSI colors or XTerm colors (application and filtering)
666 (or (require 'xterm-color nil t)
667 (require 'ansi-color))
669 (defalias 'elpher-color-filter-apply
670 (if (fboundp 'xterm-color-filter)
672 (let ((_xterm-color-render nil))
673 (xterm-color-filter s)))
674 #'ansi-color-filter-apply)
675 "A function to filter out ANSI escape sequences.")
677 (defalias 'elpher-color-apply
678 (if (fboundp 'xterm-color-filter)
681 "A function to apply ANSI escape sequences.")
683 ;;; Processing text for display
685 (defun elpher-process-text-for-display (string)
686 "Perform any desired processing of STRING prior to display as text.
687 Currently includes buttonifying URLs and processing ANSI escape codes."
688 (elpher-buttonify-urls (if elpher-filter-ansi-from-text
689 (elpher-color-filter-apply string)
690 (elpher-color-apply string))))
693 ;;; Network error reporting
696 (defun elpher-network-error (address error)
697 "Display ERROR message following unsuccessful negotiation with ADDRESS.
698 ERROR can be either an error object or a string."
699 (elpher-with-clean-buffer
700 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
701 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
702 (if (stringp error) error (error-message-string error)) "\n"
703 (propertize "\n----------------\n\n" 'face 'error)
704 "Press 'u' to return to the previous page.")))
707 ;;; General network communication
710 (defvar elpher-network-timer nil
711 "Timer used for network connections.")
713 (defvar elpher-use-tls nil
714 "If non-nil, use TLS to communicate with gopher servers.")
716 (defvar elpher-client-certificate nil
717 "If non-nil, contains client certificate details to use for TLS connections.")
719 (defun elpher-process-cleanup ()
720 "Immediately shut down any extant elpher process and timers."
721 (let ((p (get-process "elpher-process")))
722 (if p (delete-process p)))
723 (if (timerp elpher-network-timer)
724 (cancel-timer elpher-network-timer)))
726 (defun elpher-make-network-timer (thunk)
727 "Create a timer to run the THUNK after `elpher-connection-timeout' seconds.
728 This is just a wraper around `run-at-time' which additionally sets the
729 buffer-local variable `elpher-network-timer' to allow
730 `elpher-process-cleanup' to also clear the timer."
731 (let ((timer (run-at-time elpher-connection-timeout nil thunk)))
732 (setq-local elpher-network-timer timer)
735 (defun elpher-get-host-response (address default-port query-string response-processor
736 &optional use-tls force-ipv4)
737 "Generic function for retrieving data from ADDRESS.
739 When ADDRESS lacks a specific port, DEFAULT-PORT is used instead.
740 QUERY-STRING is a string sent to the host specified by ADDRESS to
741 illicet a response. This response is passed as an argument to the
742 function RESPONSE-PROCESSOR.
744 If non-nil, USE-TLS specifies that the connection is to be made over
745 TLS. If set to gemini, the certificate verification will be disabled
746 unless `elpher-gemini-TLS-cert-checks' is non-nil.
748 If non-nil, FORCE-IPV4 causes the network connection to be made over
749 ipv4 only. (The default behaviour when this is not set depends on
750 the host operating system and the local network capabilities.)"
751 (if (and use-tls (not (gnutls-available-p)))
752 (error "Use of TLS requires Emacs to be compiled with GNU TLS support")
753 (unless (< (elpher-address-port address) 65536)
754 (error "Cannot establish network connection: port number > 65536"))
755 (when (and (eq use-tls 'gemini) (not elpher-gemini-TLS-cert-checks))
756 (setq-local network-security-level 'low)
757 (setq-local gnutls-verify-error nil))
759 (let* ((kill-buffer-query-functions nil)
760 (port (elpher-address-port address))
761 (host (elpher-address-host address))
762 (service (if (> port 0) port default-port))
763 (response-string-parts nil)
766 (socks (or elpher-socks-always (string-suffix-p ".onion" host)))
767 (gnutls-params (list :type 'gnutls-x509pki
770 (elpher-get-current-keylist address)))
771 (timer (elpher-make-network-timer
773 (elpher-process-cleanup)
775 ; Try again with IPv4
776 ((not (or force-ipv4 socks))
777 (message "Connection timed out. Retrying with IPv4.")
778 (elpher-get-host-response address default-port
783 (not (eq use-tls 'gemini))
784 (or elpher-auto-disengage-TLS
786 "TLS connetion failed. Disable TLS mode and retry? ")))
787 (setq elpher-use-tls nil)
788 (elpher-get-host-response address default-port
793 (elpher-network-error address "Connection time-out."))))))
794 (proc (if socks (socks-open-network-stream "elpher-process" nil host service)
795 (make-network-process :name "elpher-process"
797 :family (and force-ipv4 'ipv4)
803 (cons 'gnutls-x509pki
804 (apply #'gnutls-boot-parameters
806 (setq elpher-network-timer timer)
807 (set-process-coding-system proc 'binary 'binary)
808 (set-process-query-on-exit-flag proc nil)
809 (elpher-buffer-message (concat "Connecting to " host "..."
810 " (press 'u' to abort)"))
811 (set-process-filter proc
812 (lambda (_proc string)
816 (setq bytes-received (+ bytes-received (length string)))
817 (let ((new-hkbytes-received (/ bytes-received 102400)))
818 (when (> new-hkbytes-received hkbytes-received)
819 (setq hkbytes-received new-hkbytes-received)
820 (elpher-buffer-message
822 (number-to-string (/ hkbytes-received 10.0))
825 (setq response-string-parts
826 (cons string response-string-parts))))
827 (set-process-sentinel proc
830 (cancel-timer timer))
831 (condition-case the-error
833 ((string-prefix-p "open" event) ; request URL
834 (elpher-buffer-message
835 (concat "Connected to " host ". Receiving data..."
836 " (press 'u' to abort)"))
837 (let ((inhibit-eol-conversion t))
838 (process-send-string proc query-string)))
839 ((string-prefix-p "deleted" event)) ; do nothing
840 ((and (not response-string-parts)
841 (not (or elpher-ipv4-always force-ipv4 socks)))
842 ; Try again with IPv4
843 (message "Connection failed. Retrying with IPv4.")
844 (elpher-get-host-response address default-port
848 (response-string-parts
849 (elpher-with-clean-buffer
850 (insert "Data received. Rendering..."))
851 (funcall response-processor
852 (apply #'concat (reverse response-string-parts)))
853 (elpher-restore-pos))
855 (error "No response from server")))
857 (elpher-network-error address the-error)))))
859 (if use-tls (apply #'gnutls-negotiate :process proc gnutls-params))
860 (funcall (process-sentinel proc) proc "open\n")))
862 (elpher-process-cleanup)
863 (error "Error initiating connection to server")))))
866 ;;; Client-side TLS Certificate Management
869 (defun elpher-generate-certificate (common-name key-file cert-file &optional temporary)
870 "Generate a key and a self-signed client TLS certificate using openssl.
872 The Common Name field of the certificate is set to COMMON-NAME. The
873 arguments KEY-FILE and CERT-FILE should contain the absolute paths of
874 the key and certificate files to write.
876 If TEMPORARY is non-nil, the certificate will be given an exporation
877 period of one day, and the key and certificate files will be deleted
878 when the certificate is no longer needed for the current session.
880 Otherwise, the certificate will be given a 100 year expiration period
881 and the files will not be deleted.
883 The function returns a list containing the current host name, the
884 temporary flag, and the key and cert file names in the form required
885 by `gnutls-boot-parameters`."
886 (let ((exp-key-file (expand-file-name key-file))
887 (exp-cert-file (expand-file-name cert-file)))
890 (call-process elpher-openssl-command nil nil nil
891 "req" "-x509" "-newkey" "rsa:2048"
892 "-days" (if temporary "1" "36500")
894 "-subj" (concat "/CN=" common-name)
895 "-keyout" exp-key-file
896 "-out" exp-cert-file)
897 (list (elpher-address-host (elpher-page-address elpher-current-page))
898 temporary exp-key-file exp-cert-file))
900 (message "Check that openssl is installed, or customize `elpher-openssl-command`.")
901 (error "Program 'openssl', required for certificate generation, not found")))))
903 (defun elpher-generate-throwaway-certificate ()
904 "Generate and return details of a throwaway certificate.
905 The key and certificate files will be deleted when they are no
906 longer needed for this session."
907 (let* ((file-base (make-temp-name "elpher"))
908 (key-file (concat temporary-file-directory file-base ".key"))
909 (cert-file (concat temporary-file-directory file-base ".crt")))
910 (elpher-generate-certificate file-base key-file cert-file t)))
912 (defun elpher-generate-persistent-certificate (file-base common-name)
913 "Generate and return details of a persistent certificate.
914 The argument FILE-BASE is used as the base for the key and certificate
915 files, while COMMON-NAME specifies the common name field of the
918 The key and certificate files are written to in `elpher-certificate-directory'."
919 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
920 (cert-file (concat elpher-certificate-directory file-base ".crt")))
921 (elpher-generate-certificate common-name key-file cert-file)))
923 (defun elpher-get-existing-certificate (file-base)
924 "Return a certificate object corresponding to an existing certificate.
925 It is assumed that the key files FILE-BASE.key and FILE-BASE.crt exist in
926 the directory `elpher-certificate-directory'."
927 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
928 (cert-file (concat elpher-certificate-directory file-base ".crt")))
929 (list (elpher-address-host (elpher-page-address elpher-current-page))
931 (expand-file-name key-file)
932 (expand-file-name cert-file))))
934 (defun elpher-install-and-use-existing-certificate (key-file-src cert-file-src file-base)
935 "Install a key+certificate file pair in `elpher-certificate-directory'.
936 The strings KEY-FILE-SRC and CERT-FILE-SRC are the existing key and
937 certificate files to install. The argument FILE-BASE is used as the
938 base for the installed key and certificate files."
939 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
940 (cert-file (concat elpher-certificate-directory file-base ".crt")))
941 (if (or (file-exists-p key-file)
942 (file-exists-p cert-file))
943 (error "A certificate with base name %s is already installed" file-base))
944 (copy-file key-file-src key-file)
945 (copy-file cert-file-src cert-file)
946 (list (elpher-address-host (elpher-page-address elpher-current-page))
948 (expand-file-name key-file)
949 (expand-file-name cert-file))))
951 (defun elpher-list-existing-certificates ()
952 "Return a list of the persistent certificates in `elpher-certificate-directory'."
953 (unless (file-directory-p elpher-certificate-directory)
954 (make-directory elpher-certificate-directory))
957 (file-name-sans-extension file))
958 (directory-files elpher-certificate-directory nil "\\.key$")))
960 (defun elpher-forget-current-certificate ()
961 "Causes any current certificate to be forgotten.)
962 In the case of throwaway certificates, the key and certificate files
965 (when elpher-client-certificate
966 (unless (and (called-interactively-p 'any)
967 (not (y-or-n-p (concat "Really forget client certificate? "
968 "(Throwaway certificates will be deleted.)"))))
969 (when (cadr elpher-client-certificate)
970 (delete-file (elt elpher-client-certificate 2))
971 (delete-file (elt elpher-client-certificate 3)))
972 (setq elpher-client-certificate nil)
973 (if (called-interactively-p 'any)
974 (message "Client certificate forgotten.")))))
976 (defun elpher-get-current-keylist (address)
977 "Retrieve the `gnutls-boot-parameters'-compatable keylist.
979 This is obtained from the client certificate described by
980 `elpher-current-certificate', if one is available and the host for
981 that certificate matches the host in ADDRESS.
983 If `elpher-current-certificate' is non-nil, and its host name doesn't
984 match that of ADDRESS, the certificate is forgotten."
985 (if elpher-client-certificate
986 (if (string= (car elpher-client-certificate)
987 (elpher-address-host address))
988 (list (cddr elpher-client-certificate))
989 (elpher-forget-current-certificate)
990 (message "Disabling client certificate for new host")
995 ;;; Gopher selector retrieval
998 (defun elpher-get-gopher-response (address renderer)
999 "Get response string from gopher server at ADDRESS and render using RENDERER."
1000 (elpher-get-host-response address 70
1001 (concat (elpher-gopher-address-selector address) "\r\n")
1003 (or (string= (elpher-address-protocol address) "gophers")
1006 (defun elpher-get-gopher-page (renderer)
1007 "Getter function for gopher pages.
1008 The RENDERER procedure is used to display the contents of the page
1009 once they are retrieved from the gopher server."
1010 (let* ((address (elpher-page-address elpher-current-page))
1011 (content (elpher-get-cached-content address)))
1012 (if (and content (funcall renderer nil))
1013 (elpher-with-clean-buffer
1015 (elpher-restore-pos))
1016 (elpher-with-clean-buffer
1017 (insert "LOADING... (use 'u' to cancel)\n"))
1018 (condition-case the-error
1019 (elpher-get-gopher-response address renderer)
1021 (elpher-network-error address the-error))))))
1025 (defun elpher-insert-margin (&optional type-name)
1026 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
1029 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
1031 (propertize "[" 'face 'elpher-margin-brackets)
1032 (propertize type-name 'face 'elpher-margin-key)
1033 (propertize "]" 'face 'elpher-margin-brackets))))
1035 (insert (make-string elpher-margin-width ?\s))))
1037 (defun elpher--page-button-help (_window buffer pos)
1038 "Function called by Emacs to generate mouse-over text.
1039 The arguments specify the BUFFER and the POS within the buffer of the item
1040 for which help is required. The function returns the help to be
1041 displayed. The _WINDOW argument is currently unused."
1042 (with-current-buffer buffer
1043 (let ((button (button-at pos)))
1045 (let* ((page (button-get button 'elpher-page))
1046 (address (elpher-page-address page)))
1047 (format "mouse-1, RET: open '%s'" (if (elpher-address-about-p address)
1049 (elpher-address-to-url address))))))))
1051 (defun elpher-insert-index-record (display-string &optional address)
1052 "Function to insert an index record into the current buffer.
1053 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
1054 If ADDRESS is not supplied or nil the record is rendered as an
1055 'information' line."
1056 (let* ((type (if address (elpher-address-type address) nil))
1057 (type-map-entry (cdr (assoc type elpher-type-map))))
1059 (let* ((margin-code (elt type-map-entry 2))
1060 (face (elt type-map-entry 3))
1061 (filtered-display-string (elpher-color-filter-apply display-string))
1062 (page (elpher-make-page filtered-display-string address)))
1063 (elpher-insert-margin margin-code)
1064 (insert-text-button filtered-display-string
1067 'action #'elpher-click-link
1069 'help-echo #'elpher--page-button-help))
1071 ('nil ;; Information
1072 (elpher-insert-margin)
1073 (let ((propertized-display-string
1074 (propertize display-string 'face 'elpher-info)))
1075 (insert (elpher-process-text-for-display propertized-display-string))))
1076 (`(gopher ,selector-type) ;; Unknown
1077 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
1078 (insert (propertize display-string
1079 'face 'elpher-unknown)))))
1082 (defun elpher-click-link (button)
1083 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
1084 (let ((page (button-get button 'elpher-page)))
1085 (elpher-visit-page page)))
1087 (defun elpher-render-index (data &optional _mime-type-string)
1088 "Render DATA as an index. MIME-TYPE-STRING is unused."
1089 (elpher-with-clean-buffer
1092 (let ((data-processed (elpher-preprocess-text-response data)))
1093 (dolist (line (split-string data-processed "\n"))
1095 (unless (= (length line) 0)
1096 (let* ((type (elt line 0))
1097 (fields (split-string (substring line 1) "\t"))
1098 (display-string (elt fields 0))
1099 (selector (elt fields 1))
1100 (host (elt fields 2))
1101 (port (if (elt fields 3)
1102 (string-to-number (elt fields 3))
1104 (address (elpher-make-gopher-address type selector host port)))
1105 (elpher-insert-index-record display-string address))))))
1106 (elpher-cache-content (elpher-page-address elpher-current-page)
1111 (defun elpher-render-text (data &optional _mime-type-string)
1112 "Render DATA as text. MIME-TYPE-STRING is unused."
1113 (elpher-with-clean-buffer
1116 (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
1117 (elpher-cache-content
1118 (elpher-page-address elpher-current-page)
1123 (defun elpher-render-image (data &optional _mime-type-string)
1124 "Display DATA as image. MIME-TYPE-STRING is unused."
1127 (if (display-images-p)
1128 (let* ((image (create-image
1131 (window (get-buffer-window elpher-buffer-name)))
1133 (setf (image-property image :max-width) (window-pixel-width window))
1134 (setf (image-property image :max-height) (window-pixel-height window)))
1135 (elpher-with-clean-buffer
1136 (insert-image image)
1137 (elpher-restore-pos)))
1138 (elpher-render-download data))))
1140 ;; Search retrieval and rendering
1142 (defun elpher-get-gopher-query-page (renderer)
1143 "Getter for gopher addresses requiring input.
1144 The response is rendered using the rendering function RENDERER."
1145 (let* ((address (elpher-page-address elpher-current-page))
1146 (content (elpher-get-cached-content address))
1148 (if (and content (funcall renderer nil))
1149 (elpher-with-clean-buffer
1151 (elpher-restore-pos)
1152 (message "Displaying cached search results. Reload to perform a new search."))
1154 (let* ((query-string (read-string "Query: "))
1155 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
1156 (search-address (elpher-make-gopher-address ?1
1158 (elpher-address-host address)
1159 (elpher-address-port address)
1160 (equal (elpher-address-type address) "gophers"))))
1163 (elpher-with-clean-buffer
1164 (insert "LOADING RESULTS... (use 'u' to cancel)"))
1165 (elpher-get-gopher-response search-address renderer))
1167 (elpher-visit-previous-page))))))
1169 ;; Raw server response rendering
1171 (defun elpher-render-raw (data &optional mime-type-string)
1172 "Display raw DATA in buffer. MIME-TYPE-STRING is also displayed if provided."
1175 (elpher-with-clean-buffer
1176 (when mime-type-string
1177 (insert "MIME type specified by server: '" mime-type-string "'\n"))
1179 (goto-char (point-min)))
1180 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
1182 ;; File save "rendering"
1184 (defun elpher-render-download (data &optional _mime-type-string)
1185 "Save DATA to file. MIME-TYPE-STRING is unused."
1188 (let* ((address (elpher-page-address elpher-current-page))
1189 (selector (if (elpher-address-gopher-p address)
1190 (elpher-gopher-address-selector address)
1191 (elpher-address-filename address))))
1192 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1193 (let* ((filename-proposal (file-name-nondirectory selector))
1194 (filename (read-file-name "Download complete. Save file as: "
1196 (if (> (length filename-proposal) 0)
1199 (let ((coding-system-for-write 'binary))
1200 (with-temp-file filename
1202 (message (format "Saved to file %s." filename))))))
1206 (defun elpher-render-html (data &optional _mime-type-string)
1207 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
1208 (elpher-with-clean-buffer
1211 (let ((dom (with-temp-buffer
1213 (libxml-parse-html-region (point-min) (point-max)))))
1214 (shr-insert-document dom)))))
1216 ;; Gemini page retrieval
1218 (defvar elpher-gemini-redirect-chain)
1220 (defun elpher-get-gemini-response (address renderer)
1221 "Get response string from gemini server at ADDRESS and render using RENDERER."
1222 (elpher-get-host-response address 1965
1223 (concat (elpher-address-to-url address) "\r\n")
1224 (lambda (response-string)
1225 (elpher-process-gemini-response response-string renderer))
1228 (defun elpher-parse-gemini-response (response)
1229 "Parse the RESPONSE string and return a list of components.
1230 The list is of the form (code meta body). A response of nil implies
1231 that the response was malformed."
1232 (let ((header-end-idx (string-match "\r\n" response)))
1234 (let ((header (string-trim (substring response 0 header-end-idx)))
1235 (body (substring response (+ header-end-idx 2))))
1236 (if (>= (length header) 2)
1237 (let ((code (substring header 0 2))
1238 (meta (string-trim (substring header 2))))
1239 (list code meta body))
1240 (error "Malformed response: No response status found in header %s" header)))
1241 (error "Malformed response: No CRLF-delimited header found in response %s" response))))
1243 (defun elpher-process-gemini-response (response-string renderer)
1244 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
1245 (let ((response-components (elpher-parse-gemini-response response-string)))
1246 (let ((response-code (elt response-components 0))
1247 (response-meta (elt response-components 1))
1248 (response-body (elt response-components 2)))
1249 (pcase (elt response-code 0)
1250 (?1 ; Input required
1251 (elpher-with-clean-buffer
1252 (insert "Gemini server is requesting input."))
1253 (let* ((query-string
1254 (if (eq (elt response-code 1) ?1)
1255 (read-passwd (concat response-meta ": "))
1256 (read-string (concat response-meta ": "))))
1257 (query-address (seq-copy (elpher-page-address elpher-current-page)))
1258 (old-fname (url-filename query-address)))
1259 (setf (url-filename query-address)
1260 (concat old-fname "?" (url-build-query-string `((,query-string)))))
1261 (elpher-get-gemini-response query-address renderer)))
1262 (?2 ; Normal response
1263 (funcall renderer response-body response-meta))
1265 (message "Following redirect to %s" response-meta)
1266 (if (>= (length elpher-gemini-redirect-chain) 5)
1267 (error "More than 5 consecutive redirects followed"))
1268 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
1269 (if (member redirect-address elpher-gemini-redirect-chain)
1270 (error "Redirect loop detected"))
1271 (if (not (eq (elpher-address-type redirect-address) 'gemini))
1272 (error "Server tried to automatically redirect to non-gemini URL: %s"
1274 (elpher-page-set-address elpher-current-page redirect-address)
1275 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
1276 (elpher-get-gemini-response redirect-address renderer)))
1277 (?4 ; Temporary failure
1278 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
1279 response-code response-meta))
1280 (?5 ; Permanent failure
1281 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
1282 response-code response-meta))
1283 (?6 ; Client certificate required
1284 (elpher-with-clean-buffer
1285 (if elpher-client-certificate
1286 (insert "Gemini server does not recognise the provided TLS certificate:\n\n")
1287 (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
1289 (elpher-gemini-insert-text response-meta))
1290 (let ((chosen-certificate (elpher-choose-client-certificate)))
1291 (unless chosen-certificate
1292 (error "Gemini server requires a client certificate and none was provided"))
1293 (setq elpher-client-certificate chosen-certificate))
1294 (elpher-with-clean-buffer)
1295 (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer))
1297 (error "Gemini server response unknown: %s %s"
1298 response-code response-meta))))))
1300 (defun elpher--read-answer-polyfill (question answers)
1301 "Polyfill for `read-answer' in Emacs 26.1.
1302 QUESTION is a string containing a question, and ANSWERS
1303 is a list of possible answers."
1304 (completing-read question (mapcar 'identity answers)))
1306 (if (fboundp 'read-answer)
1307 (defalias 'elpher-read-answer 'read-answer)
1308 (defalias 'elpher-read-answer 'elpher--read-answer-polyfill))
1310 (defun elpher-choose-client-certificate ()
1311 "Prompt for a client certificate to use to establish a TLS connection."
1312 (let* ((read-answer-short t))
1313 (pcase (read-answer "What do you want to do? "
1315 "generate and use throw-away certificate")
1317 "generate new or use existing persistent certificate")
1319 "stop immediately")))
1321 (setq elpher-client-certificate (elpher-generate-throwaway-certificate)))
1323 (let* ((existing-certificates (elpher-list-existing-certificates))
1324 (file-base (completing-read
1325 "Nickname for new or existing certificate (autocompletes, empty response aborts): "
1326 existing-certificates)))
1327 (if (string-empty-p (string-trim file-base))
1329 (if (member file-base existing-certificates)
1330 (setq elpher-client-certificate
1331 (elpher-get-existing-certificate file-base))
1332 (pcase (read-answer "Generate new certificate or install externally-generated one? "
1334 "generate new certificate")
1336 "install existing certificate")
1338 "stop immediately")))
1340 (let ((common-name (read-string "Common Name field for new certificate: "
1342 (message "New key and self-signed certificate written to %s"
1343 elpher-certificate-directory)
1344 (elpher-generate-persistent-certificate file-base common-name)))
1346 (let* ((cert-file (read-file-name "Certificate file: " nil nil t))
1347 (key-file (read-file-name "Key file: " nil nil t)))
1348 (message "Key and certificate installed in %s for future use"
1349 elpher-certificate-directory)
1350 (elpher-install-and-use-existing-certificate key-file
1356 (defun elpher-get-gemini-page (renderer)
1357 "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
1358 (let* ((address (elpher-page-address elpher-current-page))
1359 (content (elpher-get-cached-content address)))
1360 (condition-case the-error
1361 (if (and content (funcall renderer nil))
1362 (elpher-with-clean-buffer
1364 (elpher-restore-pos))
1365 (elpher-with-clean-buffer
1366 (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
1367 (setq elpher-gemini-redirect-chain nil)
1368 (elpher-get-gemini-response address renderer))
1370 (elpher-network-error address the-error)))))
1372 (defun elpher-render-gemini (body &optional mime-type-string)
1373 "Render gemini response BODY with rendering MIME-TYPE-STRING."
1376 (let* ((mime-type-string* (if (or (not mime-type-string)
1377 (string-empty-p mime-type-string))
1378 "text/gemini; charset=utf-8"
1380 (mime-type-split (split-string mime-type-string* ";" t))
1381 (mime-type (string-trim (car mime-type-split)))
1382 (parameters (mapcar (lambda (s)
1383 (let ((key-val (split-string s "=")))
1384 (list (downcase (string-trim (car key-val)))
1385 (downcase (string-trim (cadr key-val))))))
1386 (cdr mime-type-split))))
1387 (when (string-prefix-p "text/" mime-type)
1388 (setq body (decode-coding-string
1390 (if (assoc "charset" parameters)
1391 (intern (cadr (assoc "charset" parameters)))
1393 (setq body (replace-regexp-in-string "\r" "" body)))
1395 ((or "text/gemini" "")
1396 (elpher-render-gemini-map body parameters))
1398 (elpher-render-html body))
1399 ((pred (string-prefix-p "text/"))
1400 (elpher-render-gemini-plain-text body parameters))
1401 ((pred (string-prefix-p "image/"))
1402 (elpher-render-image body))
1404 (elpher-render-download body))))))
1406 (defun elpher-gemini-get-link-url (link-line)
1407 "Extract the url portion of LINK-LINE, a gemini map file link line.
1408 Returns nil in the event that the contents of the line following the
1409 => prefix are empty."
1410 (let ((l (split-string (substring link-line 2))))
1412 (string-trim (elt l 0))
1415 (defun elpher-gemini-get-link-display-string (link-line)
1416 "Extract the display string portion of LINK-LINE, a gemini map file link line.
1417 Returns the url portion in the event that the display-string portion is empty."
1418 (let* ((rest (string-trim (elt (split-string link-line "=>") 1)))
1419 (idx (string-match "[ \t]" rest)))
1420 (string-trim (if idx
1421 (substring rest (+ idx 1))
1424 (defun elpher-collapse-dot-sequences (filename)
1425 "Collapse dot sequences in FILENAME.
1426 For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
1427 (let* ((path (split-string filename "/"))
1428 (path-reversed-normalized
1429 (seq-reduce (lambda (a b)
1430 (cond ((and a (equal b "..") (cdr a)))
1431 ((and (not a) (equal b "..")) a) ;leading .. are dropped
1435 (string-join (reverse path-reversed-normalized) "/")))
1437 (defun elpher-address-from-gemini-url (url)
1438 "Extract address from URL with defaults as per gemini map files.
1439 While there's obviously some redundancy here between this function and
1440 `elpher-address-from-url', gemini map file URLs require enough special
1441 treatment that a separate function is warranted."
1442 (let ((address (url-generic-parse-url url))
1443 (current-address (elpher-page-address elpher-current-page)))
1444 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
1445 (setf (url-fullness address) t)
1446 (if (url-host address) ;if there is an explicit host, filenames are absolute
1447 (if (string-empty-p (url-filename address))
1448 (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
1449 (setf (url-host address) (url-host current-address))
1450 (setf (url-portspec address) (url-portspec current-address)) ; (url-port) too slow!
1451 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
1452 (setf (url-filename address)
1453 (concat (file-name-directory (url-filename current-address))
1454 (url-filename address)))))
1455 (unless (url-type address)
1456 (setf (url-type address) (url-type current-address)))
1457 (when (equal (url-type address) "gemini")
1458 (setf (url-filename address)
1459 (elpher-collapse-dot-sequences (url-filename address)))))
1460 (elpher-remove-redundant-ports address)))
1462 (defun elpher-gemini-insert-link (link-line)
1463 "Insert link described by LINK-LINE into a text/gemini document."
1464 (let* ((url (elpher-gemini-get-link-url link-line))
1465 (display-string (elpher-gemini-get-link-display-string link-line))
1466 (address (elpher-address-from-gemini-url url))
1467 (type (if address (elpher-address-type address) nil))
1468 (type-map-entry (cdr (assoc type elpher-type-map))))
1469 (when display-string
1470 (insert elpher-gemini-link-string)
1472 (let* ((face (elt type-map-entry 3))
1473 (filtered-display-string (elpher-color-filter-apply display-string))
1474 (page (elpher-make-page filtered-display-string address)))
1475 (insert-text-button filtered-display-string
1478 'action #'elpher-click-link
1480 'help-echo #'elpher--page-button-help))
1481 (insert (propertize display-string 'face 'elpher-unknown)))
1484 (defvar elpher--gemini-page-headings nil
1485 "List of headings on the page.")
1487 (defun elpher-gemini-insert-header (header-line)
1488 "Insert header described by HEADER-LINE into a text/gemini document.
1489 The gemini map file line describing the header is given
1491 (when (string-match "^\\(#+\\)[ \t]*" header-line)
1492 (let* ((level (length (match-string 1 header-line)))
1493 (header (substring header-line (match-end 0)))
1495 (1 'elpher-gemini-heading1)
1496 (2 'elpher-gemini-heading2)
1497 (3 'elpher-gemini-heading3)
1499 (fill-column (if (display-graphic-p)
1501 (font-get (font-spec :name (face-font 'default)) :size))
1502 (font-get (font-spec :name (face-font face)) :size)) fill-column)))
1503 (setq elpher--gemini-page-headings (cons (cons header (point))
1504 elpher--gemini-page-headings))
1505 (unless (display-graphic-p)
1506 (insert (make-string level ?#) " "))
1507 (insert (propertize header 'face face))
1510 (defun elpher-gemini-insert-text (text-line)
1511 "Insert a plain non-preformatted TEXT-LINE into a text/gemini document.
1512 This function uses Emacs' auto-fill to wrap text sensibly to a maximum
1513 width defined by `elpher-gemini-max-fill-width'."
1514 (string-match "\\(^[ \t]*\\)\\(\\*[ \t]+\\|>[ \t]*\\)?" text-line)
1515 (let* ((line-prefix (match-string 2 text-line))
1516 (processed-text-line
1518 (cond ((string-prefix-p "*" line-prefix)
1520 (replace-regexp-in-string "\\*"
1521 elpher-gemini-bullet-string
1522 (match-string 0 text-line))
1523 (substring text-line (match-end 0))))
1524 ((string-prefix-p ">" line-prefix)
1525 (propertize text-line 'face 'elpher-gemini-quoted))
1528 (adaptive-fill-mode t)
1529 ;; fill-prefix is important for adaptive-fill-mode: without
1530 ;; it, multi-line list items are not indented correct
1531 (fill-prefix (if (match-string 2 text-line)
1532 (replace-regexp-in-string "[>\*]" " " (match-string 0 text-line))
1534 (insert (elpher-process-text-for-display processed-text-line))
1537 (defun elpher-render-gemini-map (data _parameters)
1538 "Render DATA as a gemini map file, PARAMETERS is currently unused."
1539 (elpher-with-clean-buffer
1540 (setq elpher--gemini-page-headings nil)
1541 (let ((preformatted nil))
1543 (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))
1544 (dolist (line (split-string data "\n"))
1546 ((string-prefix-p "```" line) (setq preformatted (not preformatted)))
1547 (preformatted (insert (elpher-process-text-for-display
1548 (propertize line 'face 'elpher-gemini-preformatted))
1550 ((string-prefix-p "=>" line)
1551 (elpher-gemini-insert-link line))
1552 ((string-prefix-p "#" line) (elpher-gemini-insert-header line))
1553 (t (elpher-gemini-insert-text line)))))
1554 (setq elpher--gemini-page-headings (nreverse elpher--gemini-page-headings))
1555 (elpher-cache-content
1556 (elpher-page-address elpher-current-page)
1559 (defun elpher-render-gemini-plain-text (data _parameters)
1560 "Render DATA as plain text file. PARAMETERS is currently unused."
1561 (elpher-with-clean-buffer
1562 (insert (elpher-process-text-for-display data))
1563 (elpher-cache-content
1564 (elpher-page-address elpher-current-page)
1568 ;; Finger page connection
1570 (defun elpher-get-finger-page (renderer)
1571 "Opens a finger connection to the current page address.
1572 The result is rendered using RENDERER."
1573 (let* ((address (elpher-page-address elpher-current-page))
1574 (content (elpher-get-cached-content address)))
1575 (if (and content (funcall renderer nil))
1576 (elpher-with-clean-buffer
1578 (elpher-restore-pos))
1579 (elpher-with-clean-buffer
1580 (insert "LOADING... (use 'u' to cancel)\n"))
1581 (condition-case the-error
1582 (let* ((kill-buffer-query-functions nil)
1583 (user (let ((filename (elpher-address-filename address)))
1584 (if (> (length filename) 1)
1585 (substring filename 1)
1586 (elpher-address-user address)))))
1587 (elpher-get-host-response address 79
1588 (concat user "\r\n")
1591 (elpher-network-error address the-error))))))
1594 ;; Telnet page connection
1596 (defun elpher-get-telnet-page (renderer)
1597 "Opens a telnet connection to the current page address (RENDERER must be nil)."
1599 (elpher-visit-previous-page)
1600 (error "Command not supported for telnet URLs"))
1601 (let* ((address (elpher-page-address elpher-current-page))
1602 (host (elpher-address-host address))
1603 (port (elpher-address-port address)))
1604 (elpher-visit-previous-page)
1610 ;; Other URL page opening
1612 (defun elpher-get-other-url-page (renderer)
1613 "Getter which attempts to open the URL specified by the current page (RENDERER must be nil)."
1615 (elpher-visit-previous-page)
1616 (error "Command not supported for general URLs"))
1617 (let* ((address (elpher-page-address elpher-current-page))
1618 (url (elpher-address-to-url address)))
1619 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1620 (message "Opening URL...")
1621 (if elpher-open-urls-with-eww
1627 (defun elpher-get-file-page (renderer)
1628 "Getter which renders a local file using RENDERER.
1629 Assumes UTF-8 encoding for all text files."
1630 (let* ((address (elpher-page-address elpher-current-page))
1631 (filename (elpher-address-filename address)))
1632 (unless (file-exists-p filename)
1633 (elpher-visit-previous-page)
1634 (error "File not found"))
1635 (unless (file-readable-p filename)
1636 (elpher-visit-previous-page)
1637 (error "Could not read from file"))
1638 (let ((body (with-temp-buffer
1639 (let ((coding-system-for-read 'binary)
1640 (coding-system-for-write 'binary))
1641 (insert-file-contents-literally filename)
1642 (encode-coding-string (buffer-string) 'raw-text)))))
1644 (funcall renderer body nil)
1645 (pcase (file-name-extension filename)
1646 ((or "gmi" "gemini")
1647 (elpher-render-gemini-map (decode-coding-string body 'utf-8) nil))
1649 (elpher-render-html (decode-coding-string body 'utf-8)))
1651 (elpher-render-text (decode-coding-string body 'utf-8)))
1652 ((or "jpg" "jpeg" "gif" "png" "bmp" "tif" "tiff")
1653 (elpher-render-image body))
1655 (elpher-render-download body))))
1656 (elpher-restore-pos))))
1659 ;; Welcome page retrieval
1661 (defun elpher-get-welcome-page (renderer)
1662 "Getter which displays the welcome page (RENDERER must be nil)."
1664 (elpher-visit-previous-page)
1665 (error "Command not supported for welcome page"))
1666 (elpher-with-clean-buffer
1667 (insert " --------------------------------------------\n"
1668 " Elpher Gopher and Gemini Client \n"
1669 " version " elpher-version "\n"
1670 " --------------------------------------------\n"
1672 "Default bindings:\n"
1674 " - TAB/Shift-TAB: next/prev item on current page\n"
1675 " - RET/mouse-1: open item under cursor\n"
1676 " - m: select an item on current page by name (autocompletes)\n"
1677 " - u/mouse-3/U: return to previous page or to the start page\n"
1678 " - g: go to a particular address (gopher, gemini, finger)\n"
1679 " - o/O: open a different address selector or the root menu of the current server\n"
1680 " - d/D: download item under cursor or current page\n"
1681 " - i/I: info on item under cursor or current page\n"
1682 " - c/C: copy URL representation of item under cursor or current page\n"
1683 " - a/A: bookmark the item under cursor or current page\n"
1684 " - B: list all bookmarks\n"
1685 " - s/S: show current history stack or all previously visted pages\n"
1686 " - r: redraw current page (using cached contents if available)\n"
1687 " - R: reload current page (regenerates cache)\n"
1688 " - !: set character coding system for gopher (default is to autodetect)\n"
1689 " - T: toggle TLS gopher mode\n"
1690 " - F: forget/discard current TLS client certificate\n"
1691 " - .: display the raw server response for the current page\n"
1693 "Start your exploration of gopher space and gemini:\n")
1694 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1695 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1696 (elpher-insert-index-record "Project Gemini home page"
1697 (elpher-address-from-url "gemini://gemini.circumlunar.space/"))
1699 "Alternatively, select a search engine and enter some search terms:\n")
1700 (elpher-insert-index-record "Gopher Search Engine (Veronica-2)"
1701 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1702 (elpher-insert-index-record "Gemini Search Engine (geminispace.info)"
1703 (elpher-address-from-url "gemini://geminispace.info/search"))
1705 "Your bookmarks are stored in your ")
1706 (let ((help-string "RET,mouse-1: Open bookmark list"))
1707 (insert-text-button "bookmark list"
1711 (call-interactively #'elpher-show-bookmarks))
1713 'help-echo help-string))
1716 "(Bookmarks from legacy elpher-bookmarks files will be automatically imported.)\n"
1719 "The gopher home of the Elpher project is here:\n")
1720 (elpher-insert-index-record "The Elpher Project Page"
1721 (elpher-make-gopher-address ?1
1725 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1727 "The following info documentation is available:\n"
1729 (insert-text-button "Elpher Manual"
1735 'help-echo help-string)
1737 (insert-text-button "Changes introduced by the latest release"
1741 (info "(elpher)News"))
1743 'help-echo help-string))
1746 (concat "(These documents should be available if you have installed Elpher \n"
1747 " using MELPA. Otherwise you may have to install the manual yourself.)\n")
1749 (elpher-restore-pos)))
1751 ;; History page retrieval
1753 (defun elpher-show-history ()
1754 "Show the current contents of elpher's history stack.
1755 Use \\[elpher-show-visited-pages] to see the entire history.
1756 This is rendered using `elpher-get-history-page' via `elpher-type-map'."
1759 (elpher-make-page "Current History Stack"
1760 (elpher-make-about-address 'history))))
1762 (defun elpher-show-visited-pages ()
1763 "Show the all the pages you've visited using Elpher.
1764 Use \\[elpher-show-history] to see just the current history stack.
1765 This is rendered using `elpher-get-visited-pages-page' via `elpher-type-map'."
1768 (elpher-make-page "Elpher Visted Pages"
1769 (elpher-make-about-address 'visited-pages))))
1771 (defun elpher-get-history-page (renderer)
1772 "Getter which displays the history page (RENDERER must be nil)."
1774 (elpher-visit-previous-page)
1775 (error "Command not supported for history page"))
1776 (elpher-display-history-links elpher-history "Current history stack"))
1778 (defun elpher-get-visited-pages-page (renderer)
1779 "Getter which displays the list of visited pages (RENDERER must be nil)."
1781 (elpher-visit-previous-page)
1782 (error "Command not supported for history page"))
1783 (elpher-display-history-links
1784 (seq-filter (lambda (page)
1785 (not (elpher-address-about-p (elpher-page-address page))))
1786 elpher-visited-pages)
1787 "All visited pages"))
1789 (defun elpher-display-history-links (pages title)
1790 "Show all PAGES in an Elpher buffer with a given TITLE."
1791 (let* ((title-line (concat " ---- " title " ----"))
1792 (footer-line (make-string (length title-line) ?-)))
1793 (elpher-with-clean-buffer
1794 (insert title-line "\n\n")
1796 (dolist (page pages)
1798 (let ((display-string (elpher-page-display-string page))
1799 (address (elpher-page-address page)))
1800 (elpher-insert-index-record display-string address))))
1801 (insert "No history items found.\n"))
1802 (insert "\n " footer-line "\n"
1803 "Select an entry or press 'u' to return to the previous page.")
1804 (elpher-restore-pos))))
1809 ;; This code allows Elpher to use the standard Emacs bookmarks: `C-x r
1810 ;; m' to add a bookmark, `C-x r l' to list bookmarks (which is where
1811 ;; you can anotate bookmarks!), `C-x r b' to jump to a bookmark, and
1812 ;; so on. See the Bookmarks section in the Emacs info manual for more.
1814 (defvar elpher-bookmark-link nil
1815 "Prefer bookmarking a link or the current page.
1816 Bind this variable dynamically, or set it to t.
1817 If you set it to t, the commands \\[bookmark-set-no-overwrite]
1818 and \\[elpher-set-bookmark-no-overwrite] do the same thing.")
1820 (defun elpher-bookmark-make-record ()
1821 "Return a bookmark record.
1822 If `elpher-bookmark-link' is non-nil and point is on a link button,
1823 return a bookmark record for that link. Otherwise, return a bookmark
1824 record for the current elpher page."
1825 (let* ((button (and elpher-bookmark-link (button-at (point))))
1827 (button-get button 'elpher-page)
1828 elpher-current-page)))
1830 (error "Cannot bookmark this link"))
1831 (let* ((address (elpher-page-address page))
1832 (url (elpher-address-to-url address))
1833 (display-string (elpher-page-display-string page))
1834 (pos (if button nil (point))))
1835 (if (elpher-address-about-p address)
1836 (error "Cannot bookmark %s" display-string)
1838 (defaults . (,display-string))
1841 (handler . elpher-bookmark-jump))))))
1844 (defun elpher-bookmark-jump (bookmark)
1845 "Handler used to open a bookmark using elpher.
1846 The argument BOOKMARK is a bookmark record passed to the function.
1847 This handler is responsible for loading the bookmark in some buffer,
1848 then making that buffer the current buffer. It should not switch
1850 (let* ((url (cdr (assq 'location bookmark)))
1851 (cleaned-url (string-trim url))
1852 (address (elpher-address-from-url cleaned-url))
1853 (page (elpher-make-page cleaned-url address)))
1854 (elpher-with-clean-buffer
1855 (elpher-visit-page page))
1856 (set-buffer (get-buffer elpher-buffer-name))
1859 (defun elpher-bookmark-link ()
1860 "Bookmark the link at point.
1861 To bookmark the current page, use \\[elpher-bookmark-current]."
1863 (let ((elpher-bookmark-link t))
1864 (bookmark-set-no-overwrite)))
1866 (defun elpher-bookmark-current ()
1867 "Bookmark the current page.
1868 To bookmark the link at point use \\[elpher-bookmark-link]."
1870 (call-interactively #'bookmark-set-no-overwrite))
1872 (defun elpher-bookmark-import (file)
1873 "Import legacy Elpher bookmarks file FILE into Emacs bookmarks."
1874 (interactive (list (if (and (boundp 'elpher-bookmarks-file)
1875 (file-readable-p elpher-bookmarks-file))
1876 elpher-bookmarks-file
1877 (read-file-name "Old Elpher bookmarks: "
1878 user-emacs-directory nil t
1879 "elpher-bookmarks"))))
1880 (dolist (bookmark (with-temp-buffer
1881 (insert-file-contents file)
1882 (read (current-buffer))))
1883 (let* ((display-string (car bookmark))
1884 (url (cadr bookmark))
1885 (record `(,display-string
1887 (handler . elpher-bookmark-jump))))
1888 (bookmark-store display-string (cdr record) t)))
1891 (defun elpher-get-bookmarks-page (renderer)
1892 "Getter which displays the bookmarks (RENDERER must be nil)."
1894 (elpher-visit-previous-page)
1895 (error "Command not supported for bookmarks page"))
1897 (let ((old-bookmarks-file (or (and (boundp 'elpher-bookmarks-file)
1898 elpher-bookmarks-file)
1899 (locate-user-emacs-file "elpher-bookmarks"))))
1900 (when (and (file-readable-p old-bookmarks-file)
1901 (y-or-n-p (concat "Legacy elpher-bookmarks file \""
1903 "\" found. Import now?")))
1904 (elpher-bookmark-import old-bookmarks-file)
1905 (rename-file old-bookmarks-file (concat old-bookmarks-file "-legacy"))))
1907 (if (and elpher-use-emacs-bookmark-menu
1910 (elpher-visit-previous-page)
1911 (call-interactively #'bookmark-bmenu-list))
1912 (elpher-with-clean-buffer
1913 (insert " ---- Elpher Bookmarks ---- \n\n")
1914 (bookmark-maybe-load-default-file)
1915 (dolist (bookmark (bookmark-maybe-sort-alist))
1916 (when (eq #'elpher-bookmark-jump (alist-get 'handler (cdr bookmark)))
1917 (let* ((name (car bookmark))
1918 (url (alist-get 'location (cdr bookmark)))
1919 (address (elpher-address-from-url url)))
1920 (elpher-insert-index-record name address))))
1921 (when (<= (line-number-at-pos) 3)
1922 (insert "No bookmarked pages found.\n"))
1923 (insert "\n --------------------------\n\n"
1924 "Select an entry or press 'u' to return to the previous page.\n\n"
1925 "Bookmarks can be renamed or deleted via the ")
1926 (insert-text-button "Emacs bookmark menu"
1929 (call-interactively #'bookmark-bmenu-list))
1931 'help-echo "RET,mouse-1: open Emacs bookmark menu")
1932 (insert (substitute-command-keys
1933 ",\nwhich can also be opened from anywhere using '\\[bookmark-bmenu-list]'."))
1934 (elpher-restore-pos))))
1936 (defun elpher-show-bookmarks ()
1937 "Interactive function to display the current list of elpher bookmarks."
1940 (elpher-make-page "Elpher Bookmarks"
1941 (elpher-make-about-address 'bookmarks))))
1949 (defun elpher-org-export-link (link description format protocol)
1950 "Export a LINK with DESCRIPTION for the given PROTOCOL and FORMAT.
1952 FORMAT is an Org export backend. DESCRIPTION may be nil. PROTOCOL may be one
1953 of gemini, gopher or finger."
1954 (let* ((url (if (equal protocol "elpher")
1955 (string-remove-prefix "elpher:" link)
1956 (format "%s:%s" protocol link)))
1957 (desc (or description url)))
1959 (`gemini (format "=> %s %s" url desc))
1960 (`html (format "<a href=\"%s\">%s</a>" url desc))
1961 (`latex (format "\\href{%s}{%s}" url desc))
1962 (_ (if (not description)
1964 (format "%s (%s)" desc url))))))
1966 (defun elpher-org-store-link ()
1967 "Store link to an `elpher' page in Org."
1968 (when (eq major-mode 'elpher-mode)
1969 (let* ((url (elpher-info-current))
1970 (desc (car elpher-current-page))
1972 ((string-prefix-p "gemini:" url) "gemini")
1973 ((string-prefix-p "gopher:" url) "gopher")
1974 ((string-prefix-p "finger:" url) "finger")
1976 (when (equal "elpher" protocol)
1977 ;; Weird link. Or special inner link?
1978 (setq url (concat "elpher:" url)))
1979 (org-link-store-props :type protocol :link url :description desc)
1982 (defun elpher-org-follow-link (link protocol)
1983 "Visit a LINK for the given PROTOCOL.
1985 PROTOCOL may be one of gemini, gopher or finger. This method also
1986 supports the old protocol elpher, where the link is self-contained."
1987 (let ((url (if (equal protocol "elpher")
1988 (string-remove-prefix "elpher:" link)
1989 (format "%s:%s" protocol link))))
1992 (defun elpher-org-mode-integration ()
1993 "Set up `elpher' integration for `org-mode'."
1994 (org-link-set-parameters
1996 :store #'elpher-org-store-link
1997 :export (lambda (link description format _plist)
1998 (elpher-org-export-link link description format "elpher"))
1999 :follow (lambda (link _arg) (elpher-org-follow-link link "elpher")))
2000 (org-link-set-parameters
2002 :export (lambda (link description format _plist)
2003 (elpher-org-export-link link description format "gemini"))
2004 :follow (lambda (link _arg) (elpher-org-follow-link link "gemini")))
2005 (org-link-set-parameters
2007 :export (lambda (link description format _plist)
2008 (elpher-org-export-link link description format "gopher"))
2009 :follow (lambda (link _arg) (elpher-org-follow-link link "gopher")))
2010 (org-link-set-parameters
2012 :export (lambda (link description format _plist)
2013 (elpher-org-export-link link description format "finger"))
2014 :follow (lambda (link _arg) (elpher-org-follow-link link "finger"))))
2016 (add-hook 'org-mode-hook #'elpher-org-mode-integration)
2021 (defun elpher-browse-url-elpher (url &rest _args)
2022 "Browse URL using Elpher. This function is used by `browse-url'."
2023 (interactive (browse-url-interactive-arg "Elpher URL: "))
2026 ;; Use elpher to open gopher, finger and gemini links
2027 ;; For recent version of `browse-url' package
2028 (if (boundp 'browse-url-default-handlers)
2030 'browse-url-default-handlers
2031 '("^\\(gopher\\|finger\\|gemini\\)://" . elpher-browse-url-elpher))
2032 ;; Patch `browse-url-browser-function' for older ones. The value of
2033 ;; that variable is `browse-url-default-browser' by default, so
2034 ;; that's the function that gets advised.
2035 (advice-add browse-url-browser-function :before-while
2036 (lambda (url &rest _args)
2037 "Handle gemini, gopher, and finger schemes using Elpher."
2038 (let ((scheme (downcase (car (split-string url ":" t)))))
2039 (if (member scheme '("gemini" "gopher" "finger"))
2040 ;; `elpher-go' always returns nil, which will stop the
2041 ;; advice chain here in a before-while
2043 ;; chain must continue, then return t.
2046 ;; Register "gemini://" as a URI scheme so `browse-url' does the right thing
2047 (with-eval-after-load 'thingatpt
2048 (add-to-list 'thing-at-point-uri-schemes "gemini://"))
2052 ;; Make mu4e aware of the gemini world
2053 (setq mu4e~view-beginning-of-url-regexp
2054 "\\(?:https?\\|gopher\\|finger\\|gemini\\)://\\|mailto:")
2058 ;; Let elpher handle gemini, gopher links in eww buffer.
2059 (setq eww-use-browse-url
2060 "\\`mailto:\\|\\(\\`gemini\\|\\`gopher\\|\\`finger\\)://")
2063 ;;; Interactive procedures
2066 (defun elpher-next-link ()
2067 "Move point to the next link on the current page."
2071 (defun elpher-prev-link ()
2072 "Move point to the previous link on the current page."
2074 (backward-button 1))
2076 (defun elpher-follow-current-link ()
2077 "Open the link or url at point."
2082 (defun elpher-go (host-or-url)
2083 "Go to a particular gopher site HOST-OR-URL.
2084 When run interactively HOST-OR-URL is read from the minibuffer."
2085 (interactive "sGopher or Gemini URL: ")
2086 (let ((trimmed-host-or-url (string-trim host-or-url)))
2087 (unless (string-empty-p trimmed-host-or-url)
2088 (let* ((address (elpher-address-from-url trimmed-host-or-url))
2089 (page (elpher-make-page trimmed-host-or-url address)))
2090 (switch-to-buffer elpher-buffer-name)
2091 (elpher-with-clean-buffer
2092 (elpher-visit-page page))
2093 nil)))) ; non-nil value is displayed by eshell
2095 (defun elpher-go-current ()
2096 "Go to a particular site read from the minibuffer, initialized with the current URL."
2098 (let* ((address (elpher-page-address elpher-current-page))
2099 (url (read-string "Gopher or Gemini URL: "
2100 (unless (elpher-address-about-p address)
2101 (elpher-address-to-url address)))))
2102 (unless (string-empty-p (string-trim url))
2103 (elpher-visit-page (elpher-make-page url (elpher-address-from-url url))))))
2105 (defun elpher-redraw ()
2106 "Redraw current page."
2108 (elpher-visit-page elpher-current-page))
2110 (defun elpher-reload ()
2111 "Reload current page."
2113 (elpher-reload-current-page))
2115 (defun elpher-toggle-tls ()
2116 "Toggle TLS encryption mode for gopher."
2118 (setq elpher-use-tls (not elpher-use-tls))
2120 (if (gnutls-available-p)
2121 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
2122 (setq elpher-use-tls nil)
2123 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
2124 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
2126 (defun elpher-view-raw ()
2127 "View raw server response for current page."
2129 (if (elpher-address-about-p (elpher-page-address elpher-current-page))
2130 (error "This page was not generated by a server")
2131 (elpher-visit-page elpher-current-page
2132 #'elpher-render-raw)))
2134 (defun elpher-back ()
2135 "Go to previous site."
2137 (elpher-visit-previous-page))
2139 (defun elpher-back-to-start ()
2140 "Go all the way back to the start page."
2142 (setq-local elpher-current-page nil)
2143 (setq-local elpher-history nil)
2144 (elpher-visit-page (elpher-make-start-page)))
2146 (defun elpher-download ()
2147 "Download the link at point."
2149 (let ((button (button-at (point))))
2151 (let ((page (button-get button 'elpher-page)))
2153 (error "Not an elpher page"))
2154 (when (elpher-address-about-p (elpher-page-address page))
2155 (error "Cannot download %s" (elpher-page-display-string page)))
2156 (elpher-visit-page (button-get button 'elpher-page)
2157 #'elpher-render-download))
2158 (error "No link selected"))))
2160 (defun elpher-download-current ()
2161 "Download the current page."
2163 (if (elpher-address-about-p (elpher-page-address elpher-current-page))
2164 (error "Cannot download %s"
2165 (elpher-page-display-string elpher-current-page))
2166 (elpher-visit-page (elpher-make-page
2167 (elpher-page-display-string elpher-current-page)
2168 (elpher-page-address elpher-current-page))
2169 #'elpher-render-download
2172 (defun elpher--build-link-map ()
2173 "Build alist mapping link names to destination pages in current buffer."
2174 (let ((link-map nil)
2175 (b (next-button (point-min) t)))
2177 (push (cons (button-label b) b) link-map)
2178 (setq b (next-button (button-start b))))
2181 (defun elpher-jump ()
2182 "Select a directory entry by name. Similar to the info browser (m)enu command."
2184 (let* ((link-map (elpher--build-link-map)))
2186 (let ((key (let ((completion-ignore-case t))
2187 (completing-read "Directory item/link: "
2189 (if (and key (> (length key) 0))
2190 (let ((b (cdr (assoc key link-map))))
2191 (goto-char (button-start b))
2192 (button-activate b)))))))
2194 (defun elpher-root-dir ()
2195 "Visit root of current server."
2197 (let ((address (elpher-page-address elpher-current-page)))
2198 (if (not (elpher-address-about-p address))
2199 (if (or (member (url-filename address) '("/" ""))
2200 (and (elpher-address-gopher-p address)
2201 (= (length (elpher-gopher-address-selector address)) 0)))
2202 (error "Already at root directory of current server")
2203 (let ((address-copy (elpher-address-from-url
2204 (elpher-address-to-url address))))
2205 (setf (url-filename address-copy) "")
2206 (elpher-go (elpher-address-to-url address-copy))))
2207 (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
2209 (defun elpher-info-page (page)
2210 "Display URL of PAGE in minibuffer."
2211 (let ((address (elpher-page-address page)))
2212 (message "%s" (elpher-address-to-url address))))
2214 (defun elpher-info-link ()
2215 "Display information on page corresponding to link at point."
2217 (let ((button (button-at (point))))
2219 (error "No item selected"))
2220 (let ((page (button-get button 'elpher-page)))
2222 (error "Not an elpher page"))
2223 (elpher-info-page page))))
2225 (defun elpher-info-current ()
2226 "Display information on current page."
2228 (elpher-info-page elpher-current-page))
2230 (defun elpher-copy-page-url (page)
2231 "Copy URL representation of address of PAGE to `kill-ring'."
2232 (let* ((address (elpher-page-address page))
2233 (url (elpher-address-to-url address)))
2234 (message "Copied \"%s\" to kill-ring/clipboard." url)
2237 (defun elpher-copy-link-url ()
2238 "Copy URL of item at point to `kill-ring'."
2240 (let ((button (button-at (point))))
2242 (error "No item selected"))
2243 (let ((page (button-get button 'elpher-page)))
2245 (error "Not an elpher page"))
2246 (elpher-copy-page-url page))))
2248 (defun elpher-copy-current-url ()
2249 "Copy URL of current page to `kill-ring'."
2251 (elpher-copy-page-url elpher-current-page))
2253 (defun elpher-set-gopher-coding-system ()
2254 "Specify an explicit character coding system for gopher selectors."
2256 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
2257 (setq elpher-user-coding-system system)
2259 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
2260 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
2266 (defvar elpher-mode-map
2267 (let ((map (make-sparse-keymap)))
2268 (define-key map (kbd "TAB") 'elpher-next-link)
2269 (define-key map (kbd "<backtab>") 'elpher-prev-link)
2270 (define-key map (kbd "C-M-i") 'elpher-prev-link)
2271 (define-key map (kbd "u") 'elpher-back)
2272 (define-key map (kbd "-") 'elpher-back)
2273 (define-key map (kbd "^") 'elpher-back)
2274 (define-key map [mouse-3] 'elpher-back)
2275 (define-key map (kbd "U") 'elpher-back-to-start)
2276 (define-key map (kbd "g") 'elpher-go)
2277 (define-key map (kbd "o") 'elpher-go-current)
2278 (define-key map (kbd "O") 'elpher-root-dir)
2279 (define-key map (kbd "s") 'elpher-show-history)
2280 (define-key map (kbd "S") 'elpher-show-visited-pages)
2281 (define-key map (kbd "r") 'elpher-redraw)
2282 (define-key map (kbd "R") 'elpher-reload)
2283 (define-key map (kbd "T") 'elpher-toggle-tls)
2284 (define-key map (kbd ".") 'elpher-view-raw)
2285 (define-key map (kbd "d") 'elpher-download)
2286 (define-key map (kbd "D") 'elpher-download-current)
2287 (define-key map (kbd "m") 'elpher-jump)
2288 (define-key map (kbd "i") 'elpher-info-link)
2289 (define-key map (kbd "I") 'elpher-info-current)
2290 (define-key map (kbd "c") 'elpher-copy-link-url)
2291 (define-key map (kbd "C") 'elpher-copy-current-url)
2292 (define-key map (kbd "a") 'elpher-bookmark-link)
2293 (define-key map (kbd "A") 'elpher-bookmark-current)
2294 (define-key map (kbd "B") 'elpher-show-bookmarks)
2295 (define-key map (kbd "!") 'elpher-set-gopher-coding-system)
2296 (define-key map (kbd "F") 'elpher-forget-current-certificate)
2297 (when (fboundp 'evil-define-key*)
2300 (kbd "TAB") 'elpher-next-link
2301 (kbd "C-") 'elpher-follow-current-link
2302 (kbd "C-t") 'elpher-back
2303 (kbd "u") 'elpher-back
2304 (kbd "-") 'elpher-back
2305 (kbd "^") 'elpher-back
2306 [mouse-3] 'elpher-back
2307 (kbd "U") 'elpher-back-to-start
2308 (kbd "g") 'elpher-go
2309 (kbd "o") 'elpher-go-current
2310 (kbd "O") 'elpher-root-dir
2311 (kbd "s") 'elpher-show-history
2312 (kbd "S") 'elpher-show-visited-pages
2313 (kbd "r") 'elpher-redraw
2314 (kbd "R") 'elpher-reload
2315 (kbd "T") 'elpher-toggle-tls
2316 (kbd ".") 'elpher-view-raw
2317 (kbd "d") 'elpher-download
2318 (kbd "D") 'elpher-download-current
2319 (kbd "m") 'elpher-jump
2320 (kbd "i") 'elpher-info-link
2321 (kbd "I") 'elpher-info-current
2322 (kbd "c") 'elpher-copy-link-url
2323 (kbd "C") 'elpher-copy-current-url
2324 (kbd "a") 'elpher-bookmark-link
2325 (kbd "A") 'elpher-bookmark-current
2326 (kbd "B") 'elpher-show-bookmarks
2327 (kbd "!") 'elpher-set-gopher-coding-system
2328 (kbd "F") 'elpher-forget-current-certificate))
2330 "Keymap for gopher client.")
2332 (define-derived-mode elpher-mode special-mode "elpher"
2333 "Major mode for elpher, an elisp gopher client.
2335 This mode is automatically enabled by the interactive
2336 functions which initialize the client, namely
2337 `elpher', and `elpher-go'."
2338 (setq-local elpher--gemini-page-headings nil)
2339 (setq-local elpher-current-page nil)
2340 (setq-local elpher-history nil)
2341 (setq-local elpher-buffer-name (buffer-name))
2342 (setq-local bookmark-make-record-function #'elpher-bookmark-make-record)
2343 (setq-local imenu-create-index-function (lambda () elpher--gemini-page-headings))
2344 (setq-local xterm-color-preserve-properties t))
2346 (when (fboundp 'evil-set-initial-state)
2347 (evil-set-initial-state 'elpher-mode 'motion))
2350 ;;; Main start procedure
2354 (defun elpher (&optional arg)
2355 "Start elpher with default landing page.
2356 The buffer used for Elpher sessions is determined by the value of
2357 ‘elpher-buffer-name’. If there is already an Elpher session active in
2358 that buffer, Emacs will simply switch to it. Otherwise, a new session
2359 will begin. A numeric prefix ARG (as in ‘\\[universal-argument] 42
2360 \\[execute-extended-command] elpher RET’) switches to the session with
2361 that number, creating it if necessary. A non numeric prefix ARG means
2362 to create a new session. Returns the buffer selected (or created)."
2364 (let* ((name (default-value 'elpher-buffer-name))
2365 (buf (cond ((numberp arg)
2366 (get-buffer-create (format "%s<%d>" name arg)))
2368 (generate-new-buffer name))
2370 (get-buffer-create name)))))
2371 (pop-to-buffer-same-window buf)
2372 (unless (buffer-modified-p)
2374 (elpher-visit-page (elpher-make-start-page))
2375 "Started Elpher."))); Otherwise (elpher) evaluates to start page string.
2377 ;;; elpher.el ends here