1 ;;; elpher.el --- A friendly gopher and gemini client -*- lexical-binding: t -*-
3 ;; Copyright (C) 2019-2022 Tim Vaughan <plugd@thelambdalab.xyz>
4 ;; Copyright (C) 2020-2022 Elpher contributors (See info manual for full list)
6 ;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
7 ;; Created: 11 April 2019
9 ;; Keywords: comm gopher
10 ;; Homepage: https://thelambdalab.xyz/elpher
11 ;; Package-Requires: ((emacs "27.1"))
13 ;; This file is not part of GNU Emacs.
15 ;; This program is free software: you can redistribute it and/or modify
16 ;; it under the terms of the GNU General Public License as published by
17 ;; the Free Software Foundation, either version 3 of the License, or
18 ;; (at your option) any later version.
20 ;; This program is distributed in the hope that it will be useful,
21 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
22 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 ;; GNU General Public License for more details.
25 ;; You should have received a copy of the GNU General Public License
26 ;; along with this file. If not, see <http://www.gnu.org/licenses/>.
30 ;; Elpher aims to provide a practical and friendly gopher and gemini
31 ;; client for GNU Emacs. It supports:
33 ;; - intuitive keyboard and mouse-driven browsing,
34 ;; - out-of-the-box compatibility with evil-mode,
35 ;; - clickable web and gopher links *in plain text*,
36 ;; - caching of visited sites,
37 ;; - pleasant and configurable colouring of Gopher directories,
38 ;; - direct visualisation of image files,
39 ;; - gopher connections using TLS encryption,
40 ;; - the fledgling Gemini protocol,
41 ;; - the greybeard Finger protocol.
43 ;; To launch Elpher, simply use 'M-x elpher'. This will open a start
44 ;; page containing information on key bindings and suggested starting
45 ;; points for your gopher exploration.
47 ;; Full instructions can be found in the Elpher info manual.
49 ;; Elpher is under active development. Any suggestions for
50 ;; improvements are welcome, and can be made on the official project
51 ;; page, gopher://thelambdalab.xyz/1/projects/elpher, or via the
52 ;; project mailing list at https://lists.sr.ht/~michel-slm/elpher.
73 (defconst elpher-version "3.4.1"
74 "Current version of elpher.")
76 (defconst elpher-margin-width 6
77 "Width of left-hand margin used when rendering indicies.")
79 (defconst elpher-type-map
80 '(((gopher ?0) elpher-get-gopher-page elpher-render-text "txt" elpher-text)
81 ((gopher ?1) elpher-get-gopher-page elpher-render-index "/" elpher-index)
82 ((gopher ?4) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
83 ((gopher ?5) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
84 ((gopher ?7) elpher-get-gopher-query-page elpher-render-index "?" elpher-search)
85 ((gopher ?9) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
86 ((gopher ?g) elpher-get-gopher-page elpher-render-image "img" elpher-image)
87 ((gopher ?p) elpher-get-gopher-page elpher-render-image "img" elpher-image)
88 ((gopher ?I) elpher-get-gopher-page elpher-render-image "img" elpher-image)
89 ((gopher ?d) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
90 ((gopher ?P) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
91 ((gopher ?s) elpher-get-gopher-page elpher-render-download "snd" elpher-binary)
92 ((gopher ?h) elpher-get-gopher-page elpher-render-html "htm" elpher-html)
93 (gemini elpher-get-gemini-page elpher-render-gemini "gem" elpher-gemini)
94 (finger elpher-get-finger-page elpher-render-text "txt" elpher-text)
95 (telnet elpher-get-telnet-page nil "tel" elpher-telnet)
96 (other-url elpher-get-other-url-page nil "url" elpher-other-url)
97 (file elpher-get-file-page nil "~" elpher-gemini)
98 ((about welcome) elpher-get-welcome-page nil "E" elpher-index)
99 ((about bookmarks) elpher-get-bookmarks-page nil "E" elpher-index)
100 ((about history) elpher-get-history-page nil "E" elpher-index)
101 ((about visited-pages) elpher-get-visited-pages-page nil "E" elpher-index))
102 "Association list from types to getters, renderers, margin codes and index faces.")
105 ;;; Declarations to avoid compiler warnings.
109 (declare-function ansi-color-filter-apply "ansi-color")
110 (declare-function ansi-color-apply "ansi-color")
111 (declare-function bookmark-store "bookmark")
112 (declare-function org-link-store-props "ol")
113 (declare-function org-link-set-parameters "ol")
114 (defvar ansi-color-context)
115 (defvar xterm-color--current-fg)
116 (defvar xterm-color--current-bg)
117 (defvar bookmark-make-record-function)
118 (defvar mu4e~view-beginning-of-url-regexp)
119 (defvar eww-use-browse-url)
120 (defvar thing-at-point-uri-schemes))
123 ;;; Customization group
127 "A gopher and gemini client."
128 :group 'applications)
130 ;; General appearance and customizations
132 (defcustom elpher-open-urls-with-eww nil
133 "If non-nil, open URL selectors using eww.
134 Otherwise, use the system browser via the `browse-url' function."
137 (defcustom elpher-use-header t
138 "If non-nil, display current page information in buffer header."
141 (defcustom elpher-auto-disengage-TLS nil
142 "If non-nil, automatically disengage TLS following an unsuccessful connection.
143 While enabling this may seem convenient, it is also potentially
144 dangerous as it allows switching from an encrypted channel back to
145 plain text without user input."
148 (defcustom elpher-connection-timeout 5
149 "Specifies the number of seconds to wait for a network connection to time out."
152 (defcustom elpher-filter-ansi-from-text nil
153 "If non-nil, filter ANSI escape sequences from text.
154 The default behaviour is to use the ansi-color package (or xterm-color if it is
155 available) to interpret these sequences."
158 (defcustom elpher-certificate-directory
159 (file-name-as-directory (locate-user-emacs-file "elpher-certificates"))
160 "Specify the name of the directory where client certificates will be stored.
161 These certificates may be used for establishing authenticated TLS connections."
164 (defcustom elpher-openssl-command "openssl"
165 "The command used to launch openssl when generating TLS client certificates."
168 (defcustom elpher-default-url-type "gopher"
169 "Default URL type (i.e. scheme) to assume if not explicitly given."
170 :type '(choice (const "gopher")
173 (defcustom elpher-gemini-TLS-cert-checks nil
174 "If non-nil, verify gemini server TLS certs using the default security level.
175 Otherwise, certificate verification is disabled.
177 This defaults to off because it is standard practice for Gemini servers
178 to use self-signed certificates, meaning that most servers provide what
179 EMACS considers to be an invalid certificate."
182 (defcustom elpher-gemini-max-fill-width 80
183 "Specify the maximum default width (in columns) of text/gemini documents.
184 The actual width used is the minimum of this value and the window width at
185 the time when the text is rendered."
188 (defcustom elpher-gemini-link-string "→ "
189 "Specify the string used to indicate links when rendering gemini maps.
193 (defcustom elpher-gemini-bullet-string "•"
194 "Specify the string used for bullets when rendering gemini maps."
197 (defcustom elpher-ipv4-always nil
198 "If non-nil, elpher will always use IPv4 to establish network connections.
199 This can be useful when browsing from a computer that supports IPv6, because
200 some servers which do not support IPv6 can take a long time to time-out."
203 (defcustom elpher-socks-always nil
204 "If non-nil, elpher will establish network connections over a SOCKS proxy.
205 Otherwise, the SOCKS proxy is only used for connections to onion services."
208 (defcustom elpher-use-emacs-bookmark-menu nil
209 "If non-nil, elpher will only use the native Emacs bookmark menu.
210 Otherwise, \\[elpher-show-bookmarks] will visit a special elpher bookmark
211 page within which all of the standard elpher keybindings are active."
214 (defcustom elpher-start-page-url "about:welcome"
215 "Specify the page displayed initially by elpher.
216 The default welcome screen is \"about:welcome\", while the bookmarks list
217 is \"about:bookmarks\". You can also specify local files via \"file:\".
219 Beware that using \"about:bookmarks\" as a start page in combination with
220 the `elpher-use-bookmark-menu' variable set to non-nil will prevent the
221 Emacs bookmark menu being accessible via \\[elpher-show-bookmarks] from
225 (defcustom elpher-gemini-hide-preformatted nil
226 "Cause elpher to hide preformatted gemini text by default.
227 When this option is enabled, preformatted text in text/gemini documents
228 is replaced with a button which can be used to toggle its display.
230 This is intended to improve accessibility, as preformatted text often
231 includes art which can be difficult for screen readers to interpret
235 (defcustom elpher-gemini-preformatted-toggle-bullet "‣ "
236 "Margin symbol used to distinguish the preformatted text toggle."
239 (defcustom elpher-gemini-preformatted-toggle-label "[Toggle Preformatted Text]"
240 "Label of button used to toggle formatted text."
243 ;; Face customizations
245 (defgroup elpher-faces nil
246 "Elpher face customizations."
249 (defface elpher-index
250 '((t :inherit font-lock-keyword-face))
251 "Face used for directory type directory records.")
255 "Face used for text type directory records.")
258 '((t :inherit default))
259 "Face used for info type directory records.")
261 (defface elpher-image
262 '((t :inherit font-lock-string-face))
263 "Face used for image type directory records.")
265 (defface elpher-search
266 '((t :inherit warning))
267 "Face used for search type directory records.")
270 '((t :inherit font-lock-comment-face))
271 "Face used for html type directory records.")
273 (defface elpher-gemini
274 '((t :inherit font-lock-constant-face))
275 "Face used for Gemini type directory records.")
277 (defface elpher-other-url
278 '((t :inherit font-lock-comment-face))
279 "Face used for other URL type links records.")
281 (defface elpher-telnet
282 '((t :inherit font-lock-function-name-face))
283 "Face used for telnet type directory records.")
285 (defface elpher-binary
286 '((t :inherit font-lock-doc-face))
287 "Face used for binary type directory records.")
289 (defface elpher-unknown
290 '((t :inherit error))
291 "Face used for directory records with unknown/unsupported types.")
293 (defface elpher-margin-key
295 "Face used for directory margin key.")
297 (defface elpher-margin-brackets
298 '((t :inherit shadow))
299 "Face used for brackets around directory margin key.")
301 (defface elpher-gemini-heading1
302 '((t :inherit bold :height 1.8))
303 "Face used for gemini heading level 1.")
305 (defface elpher-gemini-heading2
306 '((t :inherit bold :height 1.5))
307 "Face used for gemini heading level 2.")
309 (defface elpher-gemini-heading3
310 '((t :inherit bold :height 1.2))
311 "Face used for gemini heading level 3.")
313 (defface elpher-gemini-quoted
314 '((t :inherit font-lock-doc-face))
315 "Face used for gemini quoted texts.")
317 (defface elpher-gemini-preformatted
318 '((t :inherit default))
319 "Face used for gemini preformatted text.")
321 (defface elpher-gemini-preformatted-toggle
322 '((t :inherit button))
323 "Face used for buttons used to toggle display of preformatted text.")
330 ;; An elpher "address" object is either a url object or a symbol.
331 ;; Addresses with the "about" type, corresponding to pages generated
332 ;; dynamically for and by elpher. All others represent pages which
333 ;; rely on content retrieved over the network.
335 (defun elpher-address-from-url (url-string &optional default-scheme)
336 "Create a ADDRESS object corresponding to the given URL-STRING.
337 If DEFAULT-SCHEME is non-nil, this sets the scheme of the URL when one
338 is not explicitly given."
339 (let ((data (match-data))) ; Prevent parsing clobbering match data
341 (let ((url (url-generic-parse-url url-string)))
342 (unless (and (not (url-fullness url)) (url-type url))
343 (unless (url-type url)
344 (setf (url-type url) default-scheme))
345 (unless (url-host url)
346 (let ((p (split-string (url-filename url) "/" nil nil)))
347 (setf (url-host url) (car p))
348 (setf (url-filename url)
350 (concat "/" (mapconcat #'identity (cdr p) "/"))
352 (when (not (string-empty-p (url-host url)))
353 (setf (url-fullness url) t)
354 (setf (url-host url) (puny-encode-domain (url-host url))))
355 (when (or (equal "gopher" (url-type url))
356 (equal "gophers" (url-type url)))
358 (when (or (equal (url-filename url) "")
359 (equal (url-filename url) "/"))
360 (setf (url-filename url) "/1")))
361 (when (equal "gemini" (url-type url))
363 (if (equal (url-filename url) "")
364 (setf (url-filename url) "/"))))
365 (elpher-remove-redundant-ports url))
366 (set-match-data data))))
368 (defun elpher-remove-redundant-ports (address)
369 "Remove redundant port specifiers from ADDRESS.
370 Here 'redundant' means that the specified port matches the default
371 for that protocol, eg 70 for gopher."
372 (if (and (not (elpher-address-about-p address))
373 (eq (url-portspec address) ; (url-port) is too slow!
374 (pcase (url-type address)
376 ((or "gopher" "gophers") 70)
379 (setf (url-portspec address) nil))
382 (defun elpher-make-gopher-address (type selector host port &optional tls)
383 "Create an ADDRESS object using gopher directory record attributes.
384 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
385 If the optional attribute TLS is non-nil, the address will be marked as
386 requiring gopher-over-TLS."
388 ((equal type ?i) nil)
389 ((and (equal type ?h)
390 (string-prefix-p "URL:" selector))
391 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
393 (elpher-address-from-url
396 ":" (number-to-string port))))
398 (elpher-address-from-url
399 (concat "gopher" (if tls "s" "")
401 ":" (number-to-string port)
405 (defun elpher-make-about-address (type)
406 "Create an ADDRESS object corresponding to the given about address TYPE."
407 (elpher-address-from-url (concat "about:" (symbol-name type))))
409 (defun elpher-address-to-url (address)
410 "Get string representation of ADDRESS."
411 (url-encode-url (url-recreate-url address)))
413 (defun elpher-address-type (address)
414 "Retrieve type of ADDRESS object.
415 This is used to determine how to retrieve and render the document the
416 address refers to, via the table `elpher-type-map'."
417 (pcase (url-type address)
419 (list 'about (intern (url-filename address))))
420 ((or "gopher" "gophers")
422 (if (member (url-filename address) '("" "/"))
424 (string-to-char (substring (url-filename address) 1)))))
431 (defun elpher-address-about-p (address)
432 "Return non-nil if ADDRESS is an about address."
433 (pcase (elpher-address-type address) (`(about ,_) t)))
435 (defun elpher-address-gopher-p (address)
436 "Return non-nil if ADDRESS object is a gopher address."
437 (pcase (elpher-address-type address) (`(gopher ,_) t)))
439 (defun elpher-address-protocol (address)
440 "Retrieve the transport protocol for ADDRESS."
443 (defun elpher-address-filename (address)
444 "Retrieve the filename component of ADDRESS.
445 For gopher addresses this is a combination of the selector type and selector."
446 (url-unhex-string (url-filename address)))
448 (defun elpher-address-host (address)
449 "Retrieve host from ADDRESS object."
450 (let ((host-pre (url-host address)))
451 ;; The following strips out square brackets which sometimes enclose IPv6
452 ;; addresses. Doing this here rather than at the parsing stage may seem
453 ;; weird, but this lets us way we avoid having to muck with both URL parsing
454 ;; and reconstruction. It's also more efficient, as this method is not
455 ;; called during page rendering.
456 (if (and (> (length host-pre) 2)
457 (eq (elt host-pre 0) ?\[)
458 (eq (elt host-pre (- (length host-pre) 1)) ?\]))
459 (substring host-pre 1 (- (length host-pre) 1))
462 (defun elpher-address-user (address)
463 "Retrieve user from ADDRESS object."
466 (defun elpher-address-port (address)
467 "Retrieve port from ADDRESS object.
468 If no address is defined, returns 0. (This is for compatibility with
470 (let ((port (url-portspec address))) ; (url-port) is too slow!
473 (defun elpher-gopher-address-selector (address)
474 "Retrieve gopher selector from ADDRESS object."
475 (if (member (url-filename address) '("" "/"))
477 (url-unhex-string (substring (url-filename address) 2))))
482 (defvar elpher-content-cache (make-hash-table :test 'equal))
483 (defvar elpher-pos-cache (make-hash-table :test 'equal))
485 (defun elpher-get-cached-content (address)
486 "Retrieve the cached content for ADDRESS, or nil if none exists."
487 (gethash address elpher-content-cache))
489 (defun elpher-cache-content (address content)
490 "Set the content cache for ADDRESS to CONTENT."
491 (puthash address content elpher-content-cache))
493 (defun elpher-get-cached-pos (address)
494 "Retrieve the cached cursor position for ADDRESS, or nil if none exists."
495 (gethash address elpher-pos-cache))
497 (defun elpher-cache-pos (address pos)
498 "Set the cursor position cache for ADDRESS to POS."
499 (puthash address pos elpher-pos-cache))
504 (defun elpher-make-page (display-string address)
505 "Create a page with DISPLAY-STRING and ADDRESS."
506 (list display-string address))
508 (defun elpher-make-start-page ()
509 "Create the start page."
510 (elpher-make-page "Start Page"
511 (elpher-address-from-url elpher-start-page-url)))
513 (defun elpher-page-display-string (page)
514 "Retrieve the display string corresponding to PAGE."
517 (defun elpher-page-address (page)
518 "Retrieve the address corresponding to PAGE."
521 (defun elpher-page-set-address (page new-address)
522 "Set the address corresponding to PAGE to NEW-ADDRESS."
523 (setcar (cdr page) new-address))
525 (defun elpher-page-from-url (url &optional default-scheme)
526 "Create a page with address and display string defined by URL.
527 The URL is unhexed prior to its use as a display string to improve
530 If DEFAULT-SCHEME is non-nil, this scheme is applied to the URL
531 in the instance that URL itself doesn't specify one."
532 (let ((address (elpher-address-from-url url default-scheme)))
533 (elpher-make-page (elpher-address-to-iri address) address)))
535 (defun elpher-address-to-iri (address)
536 "Return an IRI for ADDRESS.
537 Decode percent-escapes and handle punycode in the domain name.
538 Drop the password, if any."
539 (let ((data (match-data)) ; Prevent parsing clobbering match data
540 (host (url-host address))
541 (pass (url-password address)))
543 (let* ((host (url-host address))
544 (pass (url-password address)))
546 (setf (url-host address) (puny-decode-domain host)))
547 (when pass ; RFC 3986 says we should not render
548 (setf (url-password address) nil)) ; the password as clear text
549 (elpher-decode (url-unhex-string (url-recreate-url address))))
550 (setf (url-host address) host)
551 (setf (url-password address) pass)
552 (set-match-data data))))
554 (defvar elpher-current-page nil
555 "The current page for this Elpher buffer.")
557 (defvar elpher-history nil
558 "The local history stack for this Elpher buffer.
559 This variable is used by `elpher-back' and
560 `elpher-show-history'.")
562 (defvar elpher-visited-pages nil
563 "The global history for all Elpher buffers.
564 This variable is used by `elpher-show-visited-pages'.")
566 (defun elpher-visit-page (page &optional renderer no-history)
567 "Visit PAGE using its own renderer or RENDERER, if non-nil.
568 Additionally, push PAGE onto the history stack and the list of
569 previously-visited pages,unless NO-HISTORY is non-nil."
571 (elpher-process-cleanup)
573 (unless (or (not elpher-current-page)
574 (equal (elpher-page-address elpher-current-page)
575 (elpher-page-address page)))
576 (push elpher-current-page elpher-history)
577 (unless (or (elpher-address-about-p (elpher-page-address page))
578 (and elpher-visited-pages
579 (equal page (car elpher-visited-pages))))
580 (push page elpher-visited-pages))))
581 (setq-local elpher-current-page page)
582 (let* ((address (elpher-page-address page))
583 (type (elpher-address-type address))
584 (type-record (cdr (assoc type elpher-type-map))))
586 (funcall (car type-record)
590 (elpher-visit-previous-page)
592 (`(gopher ,type-char)
593 (error "Unsupported gopher selector type '%c' for '%s'"
594 type-char (elpher-address-to-url address)))
596 (error "Unsupported address type '%S' for '%s'"
597 other (elpher-address-to-url address)))))))
599 (defun elpher-visit-previous-page ()
600 "Visit the previous page in the history."
602 (elpher-visit-page (pop elpher-history) nil t)
603 (error "No previous page")))
605 (defun elpher-reload-current-page ()
606 "Reload the current page, discarding any existing cached content."
607 (elpher-cache-content (elpher-page-address elpher-current-page) nil)
608 (elpher-visit-page elpher-current-page))
610 (defun elpher-save-pos ()
611 "Save the current position of point to the current page."
612 (when elpher-current-page
613 (elpher-cache-pos (elpher-page-address elpher-current-page) (point))))
615 (defun elpher-restore-pos ()
616 "Restore the position of point to that cached in the current page."
617 (let ((pos (elpher-get-cached-pos (elpher-page-address elpher-current-page))))
620 (goto-char (point-min)))))
622 (defun elpher-get-default-url-scheme ()
623 "Suggest default URL scheme for visiting addresses based on the current page."
624 (if elpher-current-page
625 (let* ((address (elpher-page-address elpher-current-page))
626 (current-type (elpher-address-type address)))
628 ((or (and 'file (guard (not elpher-history)))
630 elpher-default-url-type)
632 (url-type address))))
633 elpher-default-url-type))
636 ;;; Buffer preparation
639 (defvar elpher-buffer-name "*elpher*"
640 "The default name of the Elpher buffer.")
642 (defun elpher-update-header ()
643 "If `elpher-use-header' is true, display current page info in window header."
644 (if (and elpher-use-header elpher-current-page)
645 (let* ((display-string (elpher-page-display-string elpher-current-page))
646 (sanitized-display-string (replace-regexp-in-string "%" "%%" display-string))
647 (address (elpher-page-address elpher-current-page))
648 (tls-string (if (and (not (elpher-address-about-p address))
649 (member (elpher-address-protocol address)
650 '("gophers" "gemini")))
653 (header (concat sanitized-display-string
654 (propertize tls-string 'face 'bold))))
655 (setq header-line-format header))))
657 (defmacro elpher-with-clean-buffer (&rest args)
658 "Evaluate ARGS with a clean *elpher* buffer as current."
659 (declare (debug (body))) ;; Allow edebug to step through body
660 `(with-current-buffer elpher-buffer-name
661 (unless (eq major-mode 'elpher-mode)
662 ;; avoid resetting buffer-local variables
664 (let ((inhibit-read-only t)
665 (ansi-color-context nil)) ;; clean ansi interpreter state (also next 2 lines)
666 (setq-local xterm-color--current-fg nil)
667 (setq-local xterm-color--current-bg nil)
668 (setq-local network-security-level
669 (default-value 'network-security-level))
671 (elpher-update-header)
674 (defun elpher-buffer-message (string &optional line)
675 "Replace first line in elpher buffer with STRING.
676 If LINE is non-nil, replace that line instead."
677 (with-current-buffer elpher-buffer-name
678 (let ((inhibit-read-only t))
679 (goto-char (point-min))
682 (let ((data (match-data)))
685 (re-search-forward "^.*$")
686 (replace-match string))
687 (set-match-data data))))))
693 (defvar elpher-user-coding-system nil
694 "User-specified coding system to use for decoding text responses.")
696 (defun elpher-decode (string)
697 "Decode STRING using autodetected or user-specified coding system."
698 (decode-coding-string string
699 (if elpher-user-coding-system
700 elpher-user-coding-system
701 (detect-coding-string string t))))
703 (defun elpher-preprocess-text-response (string)
704 "Preprocess text selector response contained in STRING.
705 This involes decoding the character representation, and clearing
706 away CRs and any terminating period."
707 (elpher-decode (replace-regexp-in-string "\n\\.\n$" "\n"
708 (replace-regexp-in-string "\r" "" string))))
712 (defconst elpher-url-regex
713 "\\([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_~?/@|#-]\\)?\\)?"
714 "Regexp used to locate and buttonify URLs in text files loaded by elpher.")
716 (defun elpher-buttonify-urls (string)
717 "Turn substrings which look like urls in STRING into clickable buttons."
720 (goto-char (point-min))
721 (while (re-search-forward elpher-url-regex nil t)
722 (let ((page (elpher-page-from-url (substring-no-properties (match-string 0)))))
723 (make-text-button (match-beginning 0)
726 'action #'elpher-click-link
728 'help-echo #'elpher--page-button-help
732 ;;; ANSI colors or XTerm colors (application and filtering)
734 (or (require 'xterm-color nil t)
735 (require 'ansi-color))
737 (defalias 'elpher-color-filter-apply
738 (if (fboundp 'xterm-color-filter)
740 (let ((_xterm-color-render nil))
741 (xterm-color-filter s)))
742 #'ansi-color-filter-apply)
743 "A function to filter out ANSI escape sequences.")
745 (defalias 'elpher-color-apply
746 (if (fboundp 'xterm-color-filter)
749 "A function to apply ANSI escape sequences.")
751 (defun elpher-text-has-ansi-escapes-p (string)
752 "Return non-nil if STRING includes an ANSI escape code."
754 (string-match "\x1b\\[" string)))
756 ;;; Processing text for display
758 (defun elpher-process-text-for-display (string)
759 "Perform any desired processing of STRING prior to display as text.
760 Currently includes buttonifying URLs and processing ANSI escape codes."
761 (elpher-buttonify-urls (if (elpher-text-has-ansi-escapes-p string)
762 (if elpher-filter-ansi-from-text
763 (elpher-color-filter-apply string)
764 (elpher-color-apply string))
768 ;;; Network error reporting
771 (defun elpher-network-error (address error)
772 "Display ERROR message following unsuccessful negotiation with ADDRESS.
773 ERROR can be either an error object or a string."
774 (elpher-with-clean-buffer
775 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
776 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
777 (if (stringp error) error (error-message-string error)) "\n"
778 (propertize "\n----------------\n\n" 'face 'error)
779 "Press 'u' to return to the previous page.")))
782 ;;; General network communication
785 (defvar elpher-network-timer nil
786 "Timer used for network connections.")
788 (defvar elpher-use-tls nil
789 "If non-nil, use TLS to communicate with gopher servers.")
791 (defvar elpher-client-certificate nil
792 "If non-nil, contains client certificate details to use for TLS connections.")
794 (defun elpher-process-cleanup ()
795 "Immediately shut down any extant elpher process and timers."
796 (let ((p (get-process "elpher-process")))
797 (if p (delete-process p)))
798 (if (timerp elpher-network-timer)
799 (cancel-timer elpher-network-timer)))
801 (defun elpher-make-network-timer (thunk)
802 "Create a timer to run the THUNK after `elpher-connection-timeout' seconds.
803 This is just a wraper around `run-at-time' which additionally sets the
804 buffer-local variable `elpher-network-timer' to allow
805 `elpher-process-cleanup' to also clear the timer."
806 (let ((timer (run-at-time elpher-connection-timeout nil thunk)))
807 (setq-local elpher-network-timer timer)
810 (defun elpher-get-host-response (address default-port query-string response-processor
811 &optional use-tls force-ipv4)
812 "Generic function for retrieving data from ADDRESS.
814 When ADDRESS lacks a specific port, DEFAULT-PORT is used instead.
815 QUERY-STRING is a string sent to the host specified by ADDRESS to
816 illicet a response. This response is passed as an argument to the
817 function RESPONSE-PROCESSOR.
819 If non-nil, USE-TLS specifies that the connection is to be made over
820 TLS. If set to gemini, the certificate verification will be disabled
821 unless `elpher-gemini-TLS-cert-checks' is non-nil.
823 If non-nil, FORCE-IPV4 causes the network connection to be made over
824 ipv4 only. (The default behaviour when this is not set depends on
825 the host operating system and the local network capabilities.)"
826 (if (and use-tls (not (gnutls-available-p)))
827 (error "Use of TLS requires Emacs to be compiled with GNU TLS support")
828 (unless (< (elpher-address-port address) 65536)
829 (error "Cannot establish network connection: port number > 65536"))
830 (when (and (eq use-tls 'gemini) (not elpher-gemini-TLS-cert-checks))
831 (setq-local network-security-level 'low)
832 (setq-local gnutls-verify-error nil))
834 (let* ((kill-buffer-query-functions nil)
835 (port (elpher-address-port address))
836 (host (elpher-address-host address))
837 (service (if (> port 0) port default-port))
838 (response-string-parts nil)
841 (socks (or elpher-socks-always (string-suffix-p ".onion" host)))
842 (gnutls-params (list :type 'gnutls-x509pki
845 (elpher-get-current-keylist address)))
846 (timer (elpher-make-network-timer
848 (elpher-process-cleanup)
850 ; Try again with IPv4
851 ((not (or elpher-ipv4-always force-ipv4 socks))
852 (message "Connection timed out. Retrying with IPv4.")
853 (elpher-get-host-response address default-port
858 (not (eq use-tls 'gemini))
859 (or elpher-auto-disengage-TLS
861 "TLS connetion failed. Disable TLS mode and retry? ")))
862 (setq elpher-use-tls nil)
863 (elpher-get-host-response address default-port
868 (elpher-network-error address "Connection time-out."))))))
869 (proc (if socks (socks-open-network-stream "elpher-process" nil host service)
870 (make-network-process :name "elpher-process"
872 :family (and (or force-ipv4
880 (cons 'gnutls-x509pki
881 (apply #'gnutls-boot-parameters
883 (setq elpher-network-timer timer)
884 (set-process-coding-system proc 'binary 'binary)
885 (set-process-query-on-exit-flag proc nil)
886 (elpher-buffer-message (concat "Connecting to " host "..."
887 " (press 'u' to abort)"))
888 (set-process-filter proc
889 (lambda (_proc string)
893 (setq bytes-received (+ bytes-received (length string)))
894 (let ((new-hkbytes-received (/ bytes-received 102400)))
895 (when (> new-hkbytes-received hkbytes-received)
896 (setq hkbytes-received new-hkbytes-received)
897 (elpher-buffer-message
899 (number-to-string (/ hkbytes-received 10.0))
902 (setq response-string-parts
903 (cons string response-string-parts))))
904 (set-process-sentinel proc
907 (cancel-timer timer))
908 (condition-case the-error
910 ((string-prefix-p "open" event) ; request URL
911 (elpher-buffer-message
912 (concat "Connected to " host ". Receiving data..."
913 " (press 'u' to abort)"))
914 (let ((inhibit-eol-conversion t))
915 (process-send-string proc query-string)))
916 ((string-prefix-p "deleted" event)) ; do nothing
917 ((and (not response-string-parts)
918 (not (or elpher-ipv4-always force-ipv4 socks)))
919 ; Try again with IPv4
920 (message "Connection failed. Retrying with IPv4.")
921 (elpher-get-host-response address default-port
925 (response-string-parts
926 (elpher-with-clean-buffer
927 (insert "Data received. Rendering..."))
928 (funcall response-processor
929 (apply #'concat (reverse response-string-parts)))
930 (elpher-restore-pos))
932 (error "No response from server")))
934 (elpher-network-error address the-error)))))
936 (if use-tls (apply #'gnutls-negotiate :process proc gnutls-params))
937 (funcall (process-sentinel proc) proc "open\n")))
939 (elpher-process-cleanup)
940 (error "Error initiating connection to server")))))
943 ;;; Client-side TLS Certificate Management
946 (defun elpher-generate-certificate (common-name key-file cert-file &optional temporary)
947 "Generate a key and a self-signed client TLS certificate using openssl.
949 The Common Name field of the certificate is set to COMMON-NAME. The
950 arguments KEY-FILE and CERT-FILE should contain the absolute paths of
951 the key and certificate files to write.
953 If TEMPORARY is non-nil, the certificate will be given an exporation
954 period of one day, and the key and certificate files will be deleted
955 when the certificate is no longer needed for the current session.
957 Otherwise, the certificate will be given a 100 year expiration period
958 and the files will not be deleted.
960 The function returns a list containing the current host name, the
961 temporary flag, and the key and cert file names in the form required
962 by `gnutls-boot-parameters`."
963 (let ((exp-key-file (expand-file-name key-file))
964 (exp-cert-file (expand-file-name cert-file)))
967 (call-process elpher-openssl-command nil nil nil
968 "req" "-x509" "-newkey" "rsa:2048"
969 "-days" (if temporary "1" "36500")
971 "-subj" (concat "/CN=" common-name)
972 "-keyout" exp-key-file
973 "-out" exp-cert-file)
974 (list (elpher-address-host (elpher-page-address elpher-current-page))
975 temporary exp-key-file exp-cert-file))
977 (message "Check that openssl is installed, or customize `elpher-openssl-command`.")
978 (error "Program 'openssl', required for certificate generation, not found")))))
980 (defun elpher-generate-throwaway-certificate ()
981 "Generate and return details of a throwaway certificate.
982 The key and certificate files will be deleted when they are no
983 longer needed for this session."
984 (let* ((file-base (make-temp-name "elpher"))
985 (key-file (concat temporary-file-directory file-base ".key"))
986 (cert-file (concat temporary-file-directory file-base ".crt")))
987 (elpher-generate-certificate file-base key-file cert-file t)))
989 (defun elpher-generate-persistent-certificate (file-base common-name)
990 "Generate and return details of a persistent certificate.
991 The argument FILE-BASE is used as the base for the key and certificate
992 files, while COMMON-NAME specifies the common name field of the
995 The key and certificate files are written to in `elpher-certificate-directory'."
996 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
997 (cert-file (concat elpher-certificate-directory file-base ".crt")))
998 (elpher-generate-certificate common-name key-file cert-file)))
1000 (defun elpher-get-existing-certificate (file-base)
1001 "Return a certificate object corresponding to an existing certificate.
1002 It is assumed that the key files FILE-BASE.key and FILE-BASE.crt exist in
1003 the directory `elpher-certificate-directory'."
1004 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
1005 (cert-file (concat elpher-certificate-directory file-base ".crt")))
1006 (list (elpher-address-host (elpher-page-address elpher-current-page))
1008 (expand-file-name key-file)
1009 (expand-file-name cert-file))))
1011 (defun elpher-install-and-use-existing-certificate (key-file-src cert-file-src file-base)
1012 "Install a key+certificate file pair in `elpher-certificate-directory'.
1013 The strings KEY-FILE-SRC and CERT-FILE-SRC are the existing key and
1014 certificate files to install. The argument FILE-BASE is used as the
1015 base for the installed key and certificate files."
1016 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
1017 (cert-file (concat elpher-certificate-directory file-base ".crt")))
1018 (if (or (file-exists-p key-file)
1019 (file-exists-p cert-file))
1020 (error "A certificate with base name %s is already installed" file-base))
1021 (copy-file key-file-src key-file)
1022 (copy-file cert-file-src cert-file)
1023 (list (elpher-address-host (elpher-page-address elpher-current-page))
1025 (expand-file-name key-file)
1026 (expand-file-name cert-file))))
1028 (defun elpher-list-existing-certificates ()
1029 "Return a list of the persistent certificates in `elpher-certificate-directory'."
1030 (unless (file-directory-p elpher-certificate-directory)
1031 (make-directory elpher-certificate-directory))
1034 (file-name-sans-extension file))
1035 (directory-files elpher-certificate-directory nil "\\.key$")))
1037 (defun elpher-forget-current-certificate ()
1038 "Causes any current certificate to be forgotten.)
1039 In the case of throwaway certificates, the key and certificate files
1042 (when elpher-client-certificate
1043 (unless (and (called-interactively-p 'any)
1044 (not (y-or-n-p (concat "Really forget client certificate? "
1045 "(Throwaway certificates will be deleted.)"))))
1046 (when (cadr elpher-client-certificate)
1047 (delete-file (elt elpher-client-certificate 2))
1048 (delete-file (elt elpher-client-certificate 3)))
1049 (setq elpher-client-certificate nil)
1050 (if (called-interactively-p 'any)
1051 (message "Client certificate forgotten.")))))
1053 (defun elpher-get-current-keylist (address)
1054 "Retrieve the `gnutls-boot-parameters'-compatable keylist.
1056 This is obtained from the client certificate described by
1057 `elpher-current-certificate', if one is available and the host for
1058 that certificate matches the host in ADDRESS.
1060 If `elpher-current-certificate' is non-nil, and its host name doesn't
1061 match that of ADDRESS, the certificate is forgotten."
1062 (if elpher-client-certificate
1063 (if (string= (car elpher-client-certificate)
1064 (elpher-address-host address))
1065 (list (cddr elpher-client-certificate))
1066 (elpher-forget-current-certificate)
1067 (message "Disabling client certificate for new host")
1072 ;;; Gopher selector retrieval
1075 (defun elpher-get-gopher-response (address renderer)
1076 "Get response string from gopher server at ADDRESS and render using RENDERER."
1077 (elpher-get-host-response address 70
1078 (concat (elpher-gopher-address-selector address) "\r\n")
1080 (or (string= (elpher-address-protocol address) "gophers")
1083 (defun elpher-get-gopher-page (renderer)
1084 "Getter function for gopher pages.
1085 The RENDERER procedure is used to display the contents of the page
1086 once they are retrieved from the gopher server."
1087 (let* ((address (elpher-page-address elpher-current-page))
1088 (content (elpher-get-cached-content address)))
1089 (if (and content (funcall renderer nil))
1090 (elpher-with-clean-buffer
1092 (elpher-restore-pos))
1093 (elpher-with-clean-buffer
1094 (insert "LOADING... (use 'u' to cancel)\n"))
1095 (condition-case the-error
1096 (elpher-get-gopher-response address renderer)
1098 (elpher-network-error address the-error))))))
1102 (defun elpher-insert-margin (&optional type-name)
1103 "Insert index margin, optionally containing the TYPE-NAME, into current buffer."
1106 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
1108 (propertize "[" 'face 'elpher-margin-brackets)
1109 (propertize type-name 'face 'elpher-margin-key)
1110 (propertize "]" 'face 'elpher-margin-brackets))))
1112 (insert (make-string elpher-margin-width ?\s))))
1114 (defun elpher--page-button-help (_window buffer pos)
1115 "Function called by Emacs to generate mouse-over text.
1116 The arguments specify the BUFFER and the POS within the buffer of the item
1117 for which help is required. The function returns the help to be
1118 displayed. The _WINDOW argument is currently unused."
1119 (with-current-buffer buffer
1120 (let ((button (button-at pos)))
1122 (let* ((page (button-get button 'elpher-page))
1123 (address (elpher-page-address page)))
1124 (format "mouse-1, RET: open '%s'" (elpher-address-to-url address)))))))
1126 (defun elpher-insert-index-record (display-string &optional address)
1127 "Function to insert an index record into the current buffer.
1128 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
1129 If ADDRESS is not supplied or nil the record is rendered as an
1130 'information' line."
1131 (let* ((type (if address (elpher-address-type address) nil))
1132 (type-map-entry (cdr (assoc type elpher-type-map))))
1134 (let* ((margin-code (elt type-map-entry 2))
1135 (face (elt type-map-entry 3))
1136 (filtered-display-string (elpher-color-filter-apply display-string))
1137 (page (elpher-make-page filtered-display-string address)))
1138 (elpher-insert-margin margin-code)
1139 (insert-text-button filtered-display-string
1142 'action #'elpher-click-link
1144 'help-echo #'elpher--page-button-help))
1146 ('nil ;; Information
1147 (elpher-insert-margin)
1148 (let ((propertized-display-string
1149 (propertize display-string 'face 'elpher-info)))
1150 (insert (elpher-process-text-for-display propertized-display-string))))
1151 (`(gopher ,selector-type) ;; Unknown
1152 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
1153 (insert (propertize display-string
1154 'face 'elpher-unknown)))))
1157 (defun elpher-click-link (button)
1158 "Function called when the gopher link BUTTON is activated."
1159 (let ((page (button-get button 'elpher-page)))
1160 (elpher-visit-page page)))
1162 (defun elpher-render-index (data &optional _mime-type-string)
1163 "Render DATA as an index. MIME-TYPE-STRING is unused."
1164 (elpher-with-clean-buffer
1167 (let ((data-processed (elpher-preprocess-text-response data)))
1168 (dolist (line (split-string data-processed "\n"))
1170 (unless (= (length line) 0)
1171 (let* ((type (elt line 0))
1172 (fields (split-string (substring line 1) "\t"))
1173 (display-string (elt fields 0))
1174 (selector (elt fields 1))
1175 (host (elt fields 2))
1176 (port (if (elt fields 3)
1177 (string-to-number (elt fields 3))
1179 (address (elpher-make-gopher-address type selector host port)))
1180 (elpher-insert-index-record display-string address))))))
1181 (elpher-cache-content (elpher-page-address elpher-current-page)
1186 (defun elpher-render-text (data &optional _mime-type-string)
1187 "Render DATA as text. MIME-TYPE-STRING is unused."
1188 (elpher-with-clean-buffer
1191 (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
1192 (elpher-cache-content
1193 (elpher-page-address elpher-current-page)
1198 (defun elpher-render-image (data &optional _mime-type-string)
1199 "Display DATA as image. MIME-TYPE-STRING is unused."
1202 (if (display-images-p)
1203 (let* ((image (create-image
1207 (error "Unsupported image format")
1208 (let ((window (get-buffer-window elpher-buffer-name)))
1210 (setf (image-property image :max-width) (window-body-width window t))
1211 (setf (image-property image :max-height) (window-body-height window t))))
1212 (elpher-with-clean-buffer
1213 (insert-image image)
1214 (elpher-restore-pos))))
1215 (elpher-render-download data))))
1217 ;; Search retrieval and rendering
1219 (defun elpher-get-gopher-query-page (renderer)
1220 "Getter for gopher addresses requiring input.
1221 The response is rendered using the rendering function RENDERER."
1222 (let* ((address (elpher-page-address elpher-current-page))
1223 (content (elpher-get-cached-content address))
1225 (if (and content (funcall renderer nil))
1226 (elpher-with-clean-buffer
1228 (elpher-restore-pos)
1229 (message "Displaying cached search results. Reload to perform a new search."))
1231 (let* ((query-string (read-string "Query: "))
1232 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
1233 (search-address (elpher-make-gopher-address ?1
1235 (elpher-address-host address)
1236 (elpher-address-port address)
1237 (equal (elpher-address-type address) "gophers"))))
1240 (elpher-with-clean-buffer
1241 (insert "LOADING RESULTS... (use 'u' to cancel)"))
1242 (elpher-get-gopher-response search-address renderer))
1244 (elpher-visit-previous-page))))))
1246 ;; Raw server response rendering
1248 (defun elpher-render-raw (data &optional mime-type-string)
1249 "Display raw DATA in buffer. MIME-TYPE-STRING is also displayed if provided."
1252 (elpher-with-clean-buffer
1253 (when mime-type-string
1254 (insert "MIME type specified by server: '" mime-type-string "'\n"))
1256 (goto-char (point-min)))
1257 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
1259 ;; File save "rendering"
1261 (defun elpher-render-download (data &optional _mime-type-string)
1262 "Save DATA to file. MIME-TYPE-STRING is unused."
1265 (let* ((address (elpher-page-address elpher-current-page))
1266 (selector (if (elpher-address-gopher-p address)
1267 (elpher-gopher-address-selector address)
1268 (elpher-address-filename address))))
1269 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1270 (let* ((filename-proposal (file-name-nondirectory selector))
1271 (filename (read-file-name "Download complete. Save file as: "
1273 (if (> (length filename-proposal) 0)
1276 (let ((coding-system-for-write 'binary))
1277 (with-temp-file filename
1279 (message (format "Saved to file %s." filename))))))
1283 (defun elpher-render-html (data &optional _mime-type-string)
1284 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
1285 (elpher-with-clean-buffer
1288 (let ((dom (with-temp-buffer
1290 (libxml-parse-html-region (point-min) (point-max)))))
1291 (shr-insert-document dom)))))
1293 ;; Gemini page retrieval
1295 (defvar elpher-gemini-redirect-chain)
1297 (defun elpher-get-gemini-response (address renderer)
1298 "Get response string from gemini server at ADDRESS and render using RENDERER."
1299 (elpher-get-host-response address 1965
1300 (concat (elpher-address-to-url address) "\r\n")
1301 (lambda (response-string)
1302 (elpher-process-gemini-response response-string renderer))
1305 (defun elpher-parse-gemini-response (response)
1306 "Parse the RESPONSE string and return a list of components.
1307 The list is of the form (code meta body). A response of nil implies
1308 that the response was malformed."
1309 (let ((header-end-idx (string-match "\r\n" response)))
1311 (let ((header (string-trim (substring response 0 header-end-idx)))
1312 (body (substring response (+ header-end-idx 2))))
1313 (if (>= (length header) 2)
1314 (let ((code (substring header 0 2))
1315 (meta (string-trim (substring header 2))))
1316 (list code meta body))
1317 (error "Malformed response: No response status found in header %s" header)))
1318 (error "Malformed response: No CRLF-delimited header found in response %s" response))))
1320 (defun elpher-process-gemini-response (response-string renderer)
1321 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
1322 (let ((response-components (elpher-parse-gemini-response response-string)))
1323 (let ((response-code (elt response-components 0))
1324 (response-meta (elt response-components 1))
1325 (response-body (elt response-components 2)))
1326 (pcase (elt response-code 0)
1327 (?1 ; Input required
1328 (elpher-with-clean-buffer
1329 (insert "Gemini server is requesting input."))
1330 (let* ((query-string
1331 (if (eq (elt response-code 1) ?1)
1332 (read-passwd (concat response-meta ": "))
1333 (read-string (concat response-meta ": "))))
1334 (query-address (seq-copy (elpher-page-address elpher-current-page)))
1335 (old-fname (url-filename query-address)))
1336 (setf (url-filename query-address)
1337 (concat old-fname "?" (url-build-query-string `((,query-string)))))
1338 (elpher-get-gemini-response query-address renderer)))
1339 (?2 ; Normal response
1340 (funcall renderer response-body response-meta))
1342 (message "Following redirect to %s" response-meta)
1343 (if (>= (length elpher-gemini-redirect-chain) 5)
1344 (error "More than 5 consecutive redirects followed"))
1345 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
1346 (if (member redirect-address elpher-gemini-redirect-chain)
1347 (error "Redirect loop detected"))
1348 (if (not (eq (elpher-address-type redirect-address) 'gemini))
1349 (error "Server tried to automatically redirect to non-gemini URL: %s"
1351 (elpher-page-set-address elpher-current-page redirect-address)
1352 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
1353 (elpher-get-gemini-response redirect-address renderer)))
1354 (?4 ; Temporary failure
1355 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
1356 response-code response-meta))
1357 (?5 ; Permanent failure
1358 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
1359 response-code response-meta))
1360 (?6 ; Client certificate required
1361 (elpher-with-clean-buffer
1362 (if elpher-client-certificate
1363 (insert "Gemini server does not recognise the provided TLS certificate:\n\n")
1364 (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
1366 (elpher-gemini-insert-text response-meta))
1367 (let ((chosen-certificate (elpher-choose-client-certificate)))
1368 (unless chosen-certificate
1369 (error "Gemini server requires a client certificate and none was provided"))
1370 (setq elpher-client-certificate chosen-certificate))
1371 (elpher-with-clean-buffer)
1372 (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer))
1374 (error "Gemini server response unknown: %s %s"
1375 response-code response-meta))))))
1377 (defun elpher--read-answer-polyfill (question answers)
1378 "Polyfill for `read-answer' in Emacs 26.1.
1379 QUESTION is a string containing a question, and ANSWERS
1380 is a list of possible answers."
1381 (completing-read question (mapcar 'identity answers)))
1383 (if (fboundp 'read-answer)
1384 (defalias 'elpher-read-answer 'read-answer)
1385 (defalias 'elpher-read-answer 'elpher--read-answer-polyfill))
1387 (defun elpher-choose-client-certificate ()
1388 "Prompt for a client certificate to use to establish a TLS connection."
1389 (let* ((read-answer-short t))
1390 (pcase (read-answer "What do you want to do? "
1392 "generate and use throw-away certificate")
1394 "generate new or use existing persistent certificate")
1396 "stop immediately")))
1398 (setq elpher-client-certificate (elpher-generate-throwaway-certificate)))
1400 (let* ((existing-certificates (elpher-list-existing-certificates))
1401 (file-base (completing-read
1402 "Nickname for new or existing certificate (autocompletes, empty response aborts): "
1403 existing-certificates)))
1404 (if (string-empty-p (string-trim file-base))
1406 (if (member file-base existing-certificates)
1407 (setq elpher-client-certificate
1408 (elpher-get-existing-certificate file-base))
1409 (pcase (read-answer "Generate new certificate or install externally-generated one? "
1411 "generate new certificate")
1413 "install existing certificate")
1415 "stop immediately")))
1417 (let ((common-name (read-string "Common Name field for new certificate: "
1419 (message "New key and self-signed certificate written to %s"
1420 elpher-certificate-directory)
1421 (elpher-generate-persistent-certificate file-base common-name)))
1423 (let* ((cert-file (read-file-name "Certificate file: " nil nil t))
1424 (key-file (read-file-name "Key file: " nil nil t)))
1425 (message "Key and certificate installed in %s for future use"
1426 elpher-certificate-directory)
1427 (elpher-install-and-use-existing-certificate key-file
1433 (defun elpher-get-gemini-page (renderer)
1434 "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
1435 (let* ((address (elpher-page-address elpher-current-page))
1436 (content (elpher-get-cached-content address)))
1437 (condition-case the-error
1438 (if (and content (funcall renderer nil))
1439 (elpher-with-clean-buffer
1441 (elpher-restore-pos))
1442 (elpher-with-clean-buffer
1443 (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
1444 (setq elpher-gemini-redirect-chain nil)
1445 (elpher-get-gemini-response address renderer))
1447 (elpher-network-error address the-error)))))
1449 (defun elpher-render-gemini (body &optional mime-type-string)
1450 "Render gemini response BODY with rendering MIME-TYPE-STRING."
1453 (let* ((mime-type-string* (if (or (not mime-type-string)
1454 (string-empty-p mime-type-string))
1455 "text/gemini; charset=utf-8"
1457 (mime-type-split (split-string mime-type-string* ";" t))
1458 (mime-type (string-trim (car mime-type-split)))
1459 (parameters (mapcar (lambda (s)
1460 (let ((key-val (split-string s "=")))
1461 (list (downcase (string-trim (car key-val)))
1462 (downcase (string-trim (cadr key-val))))))
1463 (cdr mime-type-split))))
1464 (when (string-prefix-p "text/" mime-type)
1465 (setq body (decode-coding-string
1467 (if (assoc "charset" parameters)
1468 (intern (cadr (assoc "charset" parameters)))
1470 (setq body (replace-regexp-in-string "\r" "" body)))
1472 ((or "text/gemini" "")
1473 (elpher-render-gemini-map body parameters))
1475 (elpher-render-html body))
1476 ((pred (string-prefix-p "text/"))
1477 (elpher-render-gemini-plain-text body parameters))
1478 ((pred (string-prefix-p "image/"))
1479 (elpher-render-image body))
1481 (elpher-render-download body))))))
1483 (defun elpher-gemini-get-link-url (link-line)
1484 "Extract the url portion of LINK-LINE, a gemini map file link line.
1485 Returns nil in the event that the contents of the line following the
1486 => prefix are empty."
1487 (let ((l (split-string (substring link-line 2))))
1489 (string-trim (elt l 0))
1492 (defun elpher-gemini-get-link-display-string (link-line)
1493 "Extract the display string portion of LINK-LINE, a gemini map file link line.
1494 Return nil if this portion is not provided."
1495 (let* ((rest (string-trim (elt (split-string link-line "=>") 1)))
1496 (idx (string-match "[ \t]" rest)))
1498 (elpher-color-filter-apply (string-trim (substring rest (+ idx 1)))))))
1500 (defun elpher-collapse-dot-sequences (filename)
1501 "Collapse dot sequences in the (absolute) FILENAME.
1502 For instance, the filename \"/a/b/../c/./d\" will reduce to \"/a/c/d\""
1503 (let* ((path (split-string filename "/" t))
1504 (is-directory (string-match-p (rx (: (or "." ".." "/") line-end)) filename))
1505 (path-reversed-normalized
1506 (seq-reduce (lambda (a b)
1507 (cond ((equal b "..") (cdr a))
1511 (path-normalized (reverse path-reversed-normalized)))
1513 (concat "/" (string-join path-normalized "/") (and is-directory "/"))
1516 (defun elpher-address-from-gemini-url (url)
1517 "Extract address from URL with defaults as per gemini map files.
1518 While there's obviously some redundancy here between this function and
1519 `elpher-address-from-url', gemini map file URLs require enough special
1520 treatment that a separate function is warranted."
1521 (let ((address (url-generic-parse-url url))
1522 (current-address (elpher-page-address elpher-current-page)))
1523 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
1524 (if (url-host address) ;if there is an explicit host, filenames are absolute
1525 (if (string-empty-p (url-filename address))
1526 (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
1527 (setf (url-host address) (url-host current-address))
1528 (setf (url-fullness address) (url-host address)) ; set fullness to t if host is set
1529 (setf (url-portspec address) (url-portspec current-address)) ; (url-port) too slow!
1530 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
1531 (setf (url-filename address)
1532 (concat (file-name-directory (url-filename current-address))
1533 (url-filename address)))))
1534 (when (url-host address)
1535 (setf (url-host address) (puny-encode-domain (url-host address))))
1536 (unless (url-type address)
1537 (setf (url-type address) (url-type current-address)))
1538 (when (equal (url-type address) "gemini")
1539 (setf (url-filename address)
1540 (elpher-collapse-dot-sequences (url-filename address)))))
1541 (elpher-remove-redundant-ports address)))
1543 (defun elpher-gemini-insert-link (link-line)
1544 "Insert link described by LINK-LINE into a text/gemini document."
1545 (let ((url (elpher-gemini-get-link-url link-line)))
1547 (let* ((given-display-string (elpher-gemini-get-link-display-string link-line))
1548 (address (elpher-address-from-gemini-url url))
1549 (type (if address (elpher-address-type address) nil))
1550 (type-map-entry (cdr (assoc type elpher-type-map)))
1551 (fill-prefix (make-string (+ 1 (length elpher-gemini-link-string)) ?\s)))
1552 (when type-map-entry
1553 (insert elpher-gemini-link-string)
1554 (let* ((face (elt type-map-entry 3))
1555 (display-string (or given-display-string
1556 (elpher-address-to-iri address)))
1557 (page (elpher-make-page display-string
1559 (insert-text-button display-string
1562 'action #'elpher-click-link
1564 'help-echo #'elpher--page-button-help))
1567 (defun elpher-gemini-insert-header (header-line)
1568 "Insert header described by HEADER-LINE into a text/gemini document.
1569 The gemini map file line describing the header is given
1571 (when (string-match "^\\(#+\\)[ \t]*" header-line)
1572 (let* ((level (length (match-string 1 header-line)))
1573 (header (substring header-line (match-end 0)))
1575 (1 'elpher-gemini-heading1)
1576 (2 'elpher-gemini-heading2)
1577 (3 'elpher-gemini-heading3)
1579 (fill-column (if (display-graphic-p)
1581 (font-get (font-spec :name (face-font 'default)) :size))
1582 (font-get (font-spec :name (face-font face)) :size)) fill-column)))
1583 (unless (display-graphic-p)
1584 (insert (make-string level ?#) " "))
1585 (insert (propertize header
1591 (defun elpher-gemini-insert-text (text-line)
1592 "Insert a plain non-preformatted TEXT-LINE into a text/gemini document.
1593 This function uses Emacs' auto-fill to wrap text sensibly to a maximum
1594 width defined by `elpher-gemini-max-fill-width'."
1598 (group (or (: "*" (+ (any " \t")))
1599 (: ">" (* (any " \t"))))))))
1601 (let* ((line-prefix (match-string 1 text-line))
1602 (processed-text-line
1604 (cond ((string-prefix-p "*" line-prefix)
1606 (replace-regexp-in-string "\\*"
1607 elpher-gemini-bullet-string
1608 (match-string 0 text-line))
1609 (substring text-line (match-end 0))))
1610 ((string-prefix-p ">" line-prefix)
1611 (propertize text-line 'face 'elpher-gemini-quoted))
1614 (fill-prefix (if line-prefix
1615 (make-string (length (match-string 0 text-line)) ?\s)
1617 (insert (elpher-process-text-for-display processed-text-line))
1620 (defun elpher-gemini-pref-expand-collapse (button)
1621 "Function called when the preformatted text toggle BUTTON is activated."
1622 (let ((id (button-get button 'pref-id)))
1623 (if (invisible-p id)
1624 (remove-from-invisibility-spec id)
1625 (add-to-invisibility-spec id))
1628 (defun elpher-gemini-insert-preformatted-toggler (alt-text)
1629 "Insert a button for toggling the visibility of preformatted text.
1630 If non-nil, ALT-TEXT is displayed alongside the button."
1631 (let* ((url-string (url-recreate-url (elpher-page-address elpher-current-page)))
1632 (pref-id (intern (concat "pref-"
1633 (number-to-string (point))
1636 (insert elpher-gemini-preformatted-toggle-bullet)
1638 (insert (propertize (concat alt-text " ")
1639 'face 'elpher-gemin-preformatted)))
1640 (insert-text-button elpher-gemini-preformatted-toggle-label
1641 'action #'elpher-gemini-pref-expand-collapse
1643 'face 'elpher-gemini-preformatted-toggle)
1644 (add-to-invisibility-spec pref-id)
1648 (defun elpher-gemini-insert-preformatted-line (line &optional pref-id)
1649 "Insert a LINE of preformatted text.
1650 PREF-ID is the value assigned to the \"invisible\" text attribute, which
1651 can be used to toggle the display of the preformatted text."
1652 (insert (propertize (concat (elpher-process-text-for-display
1653 (propertize line 'face 'elpher-gemini-preformatted))
1656 'rear-nonsticky t)))
1658 (defun elpher-render-gemini-map (data _parameters)
1659 "Render DATA as a gemini map file, PARAMETERS is currently unused."
1660 (elpher-with-clean-buffer
1662 (setq-local buffer-invisibility-spec nil)
1663 (let ((preformatted nil)
1664 (adaptive-fill-mode nil)) ;Prevent automatic setting of fill-prefix
1665 (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))
1666 (dolist (line (split-string data "\n"))
1668 ((rx (: "```" (opt (let alt-text (+ any)))))
1672 (if elpher-gemini-hide-preformatted
1673 (elpher-gemini-insert-preformatted-toggler alt-text)
1675 ((guard preformatted)
1676 (elpher-gemini-insert-preformatted-line line preformatted))
1677 ((pred (string-prefix-p "=>"))
1678 (elpher-gemini-insert-link line))
1679 ((pred (string-prefix-p "#"))
1680 (elpher-gemini-insert-header line))
1681 (_ (elpher-gemini-insert-text line))))
1682 (elpher-cache-content
1683 (elpher-page-address elpher-current-page)
1686 (defun elpher-render-gemini-plain-text (data _parameters)
1687 "Render DATA as plain text file. PARAMETERS is currently unused."
1688 (elpher-with-clean-buffer
1689 (insert (elpher-process-text-for-display data))
1690 (elpher-cache-content
1691 (elpher-page-address elpher-current-page)
1694 (defun elpher-build-current-imenu-index ()
1695 "Build imenu index for current elpher buffer."
1697 (goto-char (point-min))
1700 (while (setq match (text-property-search-forward 'gemini-heading t t))
1702 (buffer-substring-no-properties (prop-match-beginning match)
1703 (prop-match-end match))
1704 (prop-match-beginning match))
1706 (reverse headers))))
1709 ;; Finger page connection
1711 (defun elpher-get-finger-page (renderer)
1712 "Opens a finger connection to the current page address.
1713 The result is rendered using RENDERER."
1714 (let* ((address (elpher-page-address elpher-current-page))
1715 (content (elpher-get-cached-content address)))
1716 (if (and content (funcall renderer nil))
1717 (elpher-with-clean-buffer
1719 (elpher-restore-pos))
1720 (elpher-with-clean-buffer
1721 (insert "LOADING... (use 'u' to cancel)\n"))
1722 (condition-case the-error
1723 (let* ((kill-buffer-query-functions nil)
1724 (user (let ((filename (elpher-address-filename address)))
1725 (if (> (length filename) 1)
1726 (substring filename 1)
1727 (elpher-address-user address)))))
1728 (elpher-get-host-response address 79
1729 (concat user "\r\n")
1732 (elpher-network-error address the-error))))))
1735 ;; Telnet page connection
1737 (defun elpher-get-telnet-page (renderer)
1738 "Opens a telnet connection to the current page address (RENDERER must be nil)."
1740 (elpher-visit-previous-page)
1741 (error "Command not supported for telnet URLs"))
1742 (let* ((address (elpher-page-address elpher-current-page))
1743 (host (elpher-address-host address))
1744 (port (elpher-address-port address)))
1745 (elpher-visit-previous-page)
1751 ;; Other URL page opening
1753 (defun elpher-get-other-url-page (renderer)
1754 "Getter which attempts to open the URL specified by the current page.
1755 The RENDERER argument to this getter must be nil."
1757 (elpher-visit-previous-page)
1758 (error "Command not supported for general URLs"))
1759 (let* ((address (elpher-page-address elpher-current-page))
1760 (url (elpher-address-to-url address)))
1761 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1762 (message "Opening URL...")
1763 (if elpher-open-urls-with-eww
1770 (defun elpher-get-file-page (renderer)
1771 "Getter which renders a local file using RENDERER.
1772 Assumes UTF-8 encoding for all text files."
1773 (let* ((address (elpher-page-address elpher-current-page))
1774 (filename (elpher-address-filename address)))
1775 (unless (file-exists-p filename)
1776 (elpher-visit-previous-page)
1777 (error "File not found"))
1778 (unless (file-readable-p filename)
1779 (elpher-visit-previous-page)
1780 (error "Could not read from file"))
1781 (let ((body (with-temp-buffer
1782 (let ((coding-system-for-read 'binary)
1783 (coding-system-for-write 'binary))
1784 (insert-file-contents-literally filename)
1785 (encode-coding-string (buffer-string) 'raw-text)))))
1787 (funcall renderer body nil)
1788 (pcase (file-name-extension filename)
1789 ((or "gmi" "gemini")
1790 (elpher-render-gemini-map (decode-coding-string body 'utf-8) nil))
1792 (elpher-render-html (decode-coding-string body 'utf-8)))
1794 (elpher-render-text (decode-coding-string body 'utf-8)))
1795 ((or "jpg" "jpeg" "gif" "png" "bmp" "tif" "tiff")
1796 (elpher-render-image body))
1797 ((or "gopher" "gophermap")
1798 (elpher-render-index (elpher-decode body)))
1800 (elpher-render-download body))))
1801 (elpher-restore-pos))))
1804 ;; Welcome page retrieval
1806 (defun elpher-get-welcome-page (renderer)
1807 "Getter which displays the welcome page (RENDERER must be nil)."
1809 (elpher-visit-previous-page)
1810 (error "Command not supported for welcome page"))
1811 (elpher-with-clean-buffer
1812 (insert " --------------------------------------------\n"
1813 " Elpher Gopher and Gemini Client \n"
1814 " version " elpher-version "\n"
1815 " --------------------------------------------\n"
1817 "Default bindings:\n"
1819 " - TAB/Shift-TAB: next/prev item on current page\n"
1820 " - RET/mouse-1: open item under cursor\n"
1821 " - m: select an item on current page by name (autocompletes)\n"
1822 " - u/mouse-3/U: return to previous page or to the start page\n"
1823 " - g: go to a particular address (gopher, gemini, finger)\n"
1824 " - o/O: open a different address selector or the root menu of the current server\n"
1825 " - d/D: download item under cursor or current page\n"
1826 " - i/I: info on item under cursor or current page\n"
1827 " - c/C: copy URL representation of item under cursor or current page\n"
1828 " - a/A: bookmark the item under cursor or current page\n"
1829 " - B: list all bookmarks\n"
1830 " - s/S: show current history stack or all previously visted pages\n"
1831 " - r: redraw current page (using cached contents if available)\n"
1832 " - R: reload current page (regenerates cache)\n"
1833 " - !: set character coding system for gopher (default is to autodetect)\n"
1834 " - T: toggle TLS gopher mode\n"
1835 " - F: forget/discard current TLS client certificate\n"
1836 " - .: display the raw server response for the current page\n"
1838 "Start your exploration of gopher space and gemini:\n")
1839 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1840 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1841 (elpher-insert-index-record "Project Gemini home page"
1842 (elpher-address-from-url "gemini://gemini.circumlunar.space/"))
1844 "Alternatively, select a search engine and enter some search terms:\n")
1845 (elpher-insert-index-record "Gopher Search Engine (Veronica-2)"
1846 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1847 (elpher-insert-index-record "Gemini Search Engine (geminispace.info)"
1848 (elpher-address-from-url "gemini://geminispace.info/search"))
1850 "Your bookmarks are stored in your ")
1851 (insert-text-button "bookmark list"
1853 'action #'elpher-click-link
1855 'help-echo #'elpher--page-button-help
1857 (elpher-make-page "Elpher Bookmarks"
1858 (elpher-make-about-address 'bookmarks)))
1861 "(Bookmarks from legacy elpher-bookmarks files will be automatically imported.)\n"
1864 "The gopher home of the Elpher project is here:\n")
1865 (elpher-insert-index-record "The Elpher Project Page"
1866 (elpher-make-gopher-address ?1
1870 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1872 "The following info documentation is available:\n"
1874 (insert-text-button "Elpher Manual"
1880 'help-echo help-string)
1882 (insert-text-button "Changes introduced by the latest release"
1886 (info "(elpher)News"))
1888 'help-echo help-string))
1891 (concat "(These documents should be available if you have installed Elpher\n"
1892 " from MELPA or non-GNU ELPA. Otherwise you may have to install the\n"
1893 " manual yourself.)\n")
1895 (elpher-restore-pos)))
1898 ;; History page retrieval
1900 (defun elpher-show-history ()
1901 "Show the current contents of elpher's history stack.
1902 Use \\[elpher-show-visited-pages] to see the entire history.
1903 This is rendered using `elpher-get-history-page' via `elpher-type-map'."
1906 (elpher-make-page "Current History Stack"
1907 (elpher-make-about-address 'history))))
1909 (defun elpher-show-visited-pages ()
1910 "Show the all the pages you've visited using Elpher.
1911 Use \\[elpher-show-history] to see just the current history stack.
1912 This is rendered using `elpher-get-visited-pages-page' via `elpher-type-map'."
1915 (elpher-make-page "Elpher Visted Pages"
1916 (elpher-make-about-address 'visited-pages))))
1918 (defun elpher-get-history-page (renderer)
1919 "Getter which displays the history page (RENDERER must be nil)."
1921 (elpher-visit-previous-page)
1922 (error "Command not supported for history page"))
1923 (elpher-display-history-links elpher-history "Current history stack"))
1925 (defun elpher-get-visited-pages-page (renderer)
1926 "Getter which displays the list of visited pages (RENDERER must be nil)."
1928 (elpher-visit-previous-page)
1929 (error "Command not supported for history page"))
1930 (elpher-display-history-links
1931 (seq-filter (lambda (page)
1932 (not (elpher-address-about-p (elpher-page-address page))))
1933 elpher-visited-pages)
1934 "All visited pages"))
1936 (defun elpher-display-history-links (pages title)
1937 "Show all PAGES in an Elpher buffer with a given TITLE."
1938 (let* ((title-line (concat " ---- " title " ----"))
1939 (footer-line (make-string (length title-line) ?-)))
1940 (elpher-with-clean-buffer
1941 (insert title-line "\n\n")
1943 (dolist (page pages)
1945 (let ((display-string (elpher-page-display-string page))
1946 (address (elpher-page-address page)))
1947 (elpher-insert-index-record display-string address))))
1948 (insert "No history items found.\n"))
1949 (insert "\n " footer-line "\n"
1950 "Select an entry or press 'u' to return to the previous page.")
1951 (elpher-restore-pos))))
1956 ;; This code allows Elpher to use the standard Emacs bookmarks: `C-x r
1957 ;; m' to add a bookmark, `C-x r l' to list bookmarks (which is where
1958 ;; you can anotate bookmarks!), `C-x r b' to jump to a bookmark, and
1959 ;; so on. See the Bookmarks section in the Emacs info manual for more.
1961 (defvar elpher-bookmark-link nil
1962 "Prefer bookmarking a link or the current page.
1963 Bind this variable dynamically, or set it to t.
1964 If you set it to t, the commands \\[bookmark-set-no-overwrite]
1965 and \\[elpher-set-bookmark-no-overwrite] do the same thing.")
1967 (defun elpher-bookmark-make-record ()
1968 "Return a bookmark record.
1969 If `elpher-bookmark-link' is non-nil and point is on a link button,
1970 return a bookmark record for that link. Otherwise, return a bookmark
1971 record for the current elpher page."
1972 (let* ((button (and elpher-bookmark-link (button-at (point))))
1974 (button-get button 'elpher-page)
1975 elpher-current-page)))
1977 (error "Cannot bookmark this link"))
1978 (let* ((address (elpher-page-address page))
1979 (url (elpher-address-to-url address))
1980 (display-string (elpher-page-display-string page))
1981 (pos (if button nil (point))))
1982 (if (elpher-address-about-p address)
1983 (error "Cannot bookmark %s" display-string)
1985 (defaults . (,display-string))
1988 (handler . elpher-bookmark-jump))))))
1991 (defun elpher-bookmark-jump (bookmark)
1992 "Handler used to open a bookmark using elpher.
1993 The argument BOOKMARK is a bookmark record passed to the function.
1994 This handler is responsible for loading the bookmark in some buffer,
1995 then making that buffer the current buffer. It should not switch
1997 (let* ((url (cdr (assq 'location bookmark)))
1998 (cleaned-url (string-trim url))
1999 (page (elpher-page-from-url cleaned-url))
2000 (buffer (get-buffer-create elpher-buffer-name)))
2001 (elpher-with-clean-buffer
2002 (elpher-visit-page page))
2006 (defun elpher-bookmark-link ()
2007 "Bookmark the link at point.
2008 To bookmark the current page, use \\[elpher-bookmark-current]."
2010 (let ((elpher-bookmark-link t))
2011 (bookmark-set-no-overwrite)))
2013 (defun elpher-bookmark-current ()
2014 "Bookmark the current page.
2015 To bookmark the link at point use \\[elpher-bookmark-link]."
2017 (call-interactively #'bookmark-set-no-overwrite))
2019 (defun elpher-bookmark-import (file)
2020 "Import legacy Elpher bookmarks file FILE into Emacs bookmarks."
2021 (interactive (list (if (and (boundp 'elpher-bookmarks-file)
2022 (file-readable-p elpher-bookmarks-file))
2023 elpher-bookmarks-file
2024 (read-file-name "Old Elpher bookmarks: "
2025 user-emacs-directory nil t
2026 "elpher-bookmarks"))))
2027 (dolist (bookmark (with-temp-buffer
2028 (insert-file-contents file)
2029 (read (current-buffer))))
2030 (let* ((display-string (car bookmark))
2031 (url (cadr bookmark))
2032 (record `(,display-string
2034 (handler . elpher-bookmark-jump))))
2035 (bookmark-store display-string (cdr record) t)))
2038 (defun elpher-get-bookmarks-page (renderer)
2039 "Getter which displays the bookmarks (RENDERER must be nil)."
2041 (elpher-visit-previous-page)
2042 (error "Command not supported for bookmarks page"))
2044 (let ((old-bookmarks-file (or (and (boundp 'elpher-bookmarks-file)
2045 elpher-bookmarks-file)
2046 (locate-user-emacs-file "elpher-bookmarks"))))
2047 (when (and (file-readable-p old-bookmarks-file)
2048 (y-or-n-p (concat "Legacy elpher-bookmarks file \""
2050 "\" found. Import now?")))
2051 (elpher-bookmark-import old-bookmarks-file)
2052 (rename-file old-bookmarks-file (concat old-bookmarks-file "-legacy"))))
2054 (if (and elpher-use-emacs-bookmark-menu
2057 (elpher-visit-previous-page)
2058 (call-interactively #'bookmark-bmenu-list))
2059 (elpher-with-clean-buffer
2060 (insert " ---- Elpher Bookmarks ---- \n\n")
2061 (bookmark-maybe-load-default-file)
2062 (dolist (bookmark (bookmark-maybe-sort-alist))
2063 (when (eq #'elpher-bookmark-jump (alist-get 'handler (cdr bookmark)))
2064 (let* ((name (car bookmark))
2065 (url (alist-get 'location (cdr bookmark)))
2066 (address (elpher-address-from-url url)))
2067 (elpher-insert-index-record name address))))
2068 (when (<= (line-number-at-pos) 3)
2069 (insert "No bookmarked pages found.\n"))
2070 (insert "\n --------------------------\n\n"
2071 "Select an entry or press 'u' to return to the previous page.\n\n"
2072 "Bookmarks can be renamed or deleted via the ")
2073 (insert-text-button "Emacs bookmark menu"
2076 (call-interactively #'bookmark-bmenu-list))
2078 'help-echo "RET,mouse-1: open Emacs bookmark menu")
2079 (insert (substitute-command-keys
2080 ",\nwhich can also be opened from anywhere using '\\[bookmark-bmenu-list]'."))
2081 (elpher-restore-pos))))
2083 (defun elpher-show-bookmarks ()
2084 "Interactive function to display the current list of elpher bookmarks."
2087 (elpher-make-page "Elpher Bookmarks"
2088 (elpher-make-about-address 'bookmarks))))
2096 (defun elpher-org-export-link (link description format protocol)
2097 "Export a LINK with DESCRIPTION for the given PROTOCOL and FORMAT.
2099 FORMAT is an Org export backend. DESCRIPTION may be nil. PROTOCOL may be one
2100 of gemini, gopher or finger."
2101 (let* ((url (if (equal protocol "elpher")
2102 (string-remove-prefix "elpher:" link)
2103 (format "%s:%s" protocol link)))
2104 (desc (or description url)))
2106 (`gemini (format "=> %s %s" url desc))
2107 (`html (format "<a href=\"%s\">%s</a>" url desc))
2108 (`latex (format "\\href{%s}{%s}" url desc))
2109 (_ (if (not description)
2111 (format "%s (%s)" desc url))))))
2113 (defun elpher-org-store-link ()
2114 "Store link to an `elpher' page in Org."
2115 (when (eq major-mode 'elpher-mode)
2116 (let* ((url (elpher-info-current))
2117 (desc (car elpher-current-page))
2119 ((string-prefix-p "gemini:" url) "gemini")
2120 ((string-prefix-p "gopher:" url) "gopher")
2121 ((string-prefix-p "finger:" url) "finger")
2123 (when (equal "elpher" protocol)
2124 ;; Weird link. Or special inner link?
2125 (setq url (concat "elpher:" url)))
2126 (org-link-store-props :type protocol :link url :description desc)
2129 (defun elpher-org-follow-link (link protocol)
2130 "Visit a LINK for the given PROTOCOL.
2132 PROTOCOL may be one of gemini, gopher or finger. This method also
2133 supports the old protocol elpher, where the link is self-contained."
2134 (let ((url (if (equal protocol "elpher")
2135 (string-remove-prefix "elpher:" link)
2136 (format "%s:%s" protocol link))))
2139 (defun elpher-org-mode-integration ()
2140 "Set up `elpher' integration for `org-mode'."
2141 (org-link-set-parameters
2143 :store #'elpher-org-store-link
2144 :export (lambda (link description format _plist)
2145 (elpher-org-export-link link description format "elpher"))
2146 :follow (lambda (link _arg) (elpher-org-follow-link link "elpher")))
2147 (org-link-set-parameters
2149 :export (lambda (link description format _plist)
2150 (elpher-org-export-link link description format "gemini"))
2151 :follow (lambda (link _arg) (elpher-org-follow-link link "gemini")))
2152 (org-link-set-parameters
2154 :export (lambda (link description format _plist)
2155 (elpher-org-export-link link description format "gopher"))
2156 :follow (lambda (link _arg) (elpher-org-follow-link link "gopher")))
2157 (org-link-set-parameters
2159 :export (lambda (link description format _plist)
2160 (elpher-org-export-link link description format "finger"))
2161 :follow (lambda (link _arg) (elpher-org-follow-link link "finger"))))
2163 (add-hook 'org-mode-hook #'elpher-org-mode-integration)
2168 (defun elpher-browse-url-elpher (url &rest _args)
2169 "Browse URL using Elpher. This function is used by `browse-url'."
2170 (interactive (browse-url-interactive-arg "Elpher URL: "))
2173 ;; Use elpher to open gopher, finger and gemini links
2174 ;; For recent version of `browse-url' package
2175 (if (boundp 'browse-url-default-handlers)
2177 'browse-url-default-handlers
2178 '("^\\(gopher\\|finger\\|gemini\\)://" . elpher-browse-url-elpher))
2179 ;; Patch `browse-url-browser-function' for older ones. The value of
2180 ;; that variable is `browse-url-default-browser' by default, so
2181 ;; that's the function that gets advised. If the value is an alist,
2182 ;; however, we don't know what to do. Better not interfere?
2183 (when (and (symbolp browse-url-browser-function)
2184 (fboundp browse-url-browser-function))
2185 (advice-add browse-url-browser-function :before-while
2186 (lambda (url &rest _args)
2187 "Handle gemini, gopher, and finger schemes using Elpher."
2188 (let ((scheme (downcase (car (split-string url ":" t)))))
2189 (if (member scheme '("gemini" "gopher" "finger"))
2190 ;; `elpher-go' always returns nil, which will stop the
2191 ;; advice chain here in a before-while
2193 ;; chain must continue, then return t.
2196 ;; Register "gemini://" as a URI scheme so `browse-url' does the right thing
2197 (with-eval-after-load 'thingatpt
2198 (add-to-list 'thing-at-point-uri-schemes "gemini://"))
2202 ;; Make mu4e aware of the gemini world
2203 (setq mu4e~view-beginning-of-url-regexp
2204 "\\(?:https?\\|gopher\\|finger\\|gemini\\)://\\|mailto:")
2208 ;; Let elpher handle gemini, gopher links in eww buffer.
2209 (setq eww-use-browse-url
2210 "\\`mailto:\\|\\(\\`gemini\\|\\`gopher\\|\\`finger\\)://")
2213 ;;; Interactive procedures
2216 (defun elpher-next-link ()
2217 "Move point to the next link on the current page."
2221 (defun elpher-prev-link ()
2222 "Move point to the previous link on the current page."
2224 (backward-button 1))
2226 (defun elpher-follow-current-link ()
2227 "Open the link or url at point."
2232 (defun elpher-go (host-or-url)
2233 "Go to a particular gopher site HOST-OR-URL.
2234 When run interactively HOST-OR-URL is read from the minibuffer."
2236 (read-string (format "Visit URL (default scheme %s): " (elpher-get-default-url-scheme)))))
2237 (let ((trimmed-host-or-url (string-trim host-or-url)))
2238 (unless (string-empty-p trimmed-host-or-url)
2239 (let ((page (elpher-page-from-url trimmed-host-or-url
2240 (elpher-get-default-url-scheme))))
2241 (unless (get-buffer-window elpher-buffer-name t)
2242 (switch-to-buffer elpher-buffer-name))
2243 (elpher-with-clean-buffer
2244 (elpher-visit-page page))
2245 nil)))) ; non-nil value is displayed by eshell
2247 (defun elpher-go-current ()
2248 "Go to a particular URL which is read from the minibuffer.
2249 Unlike `elpher-go', the reader is initialized with the URL of the
2252 (let* ((address (elpher-page-address elpher-current-page))
2253 (url (read-string (format "Visit URL (default scheme %s): " (elpher-get-default-url-scheme))
2254 (elpher-address-to-url address))))
2255 (unless (string-empty-p (string-trim url))
2256 (elpher-visit-page (elpher-page-from-url url)))))
2258 (defun elpher-redraw ()
2259 "Redraw current page."
2261 (elpher-visit-page elpher-current-page))
2263 (defun elpher-reload ()
2264 "Reload current page."
2266 (elpher-reload-current-page))
2268 (defun elpher-toggle-tls ()
2269 "Toggle TLS encryption mode for gopher."
2271 (setq elpher-use-tls (not elpher-use-tls))
2273 (if (gnutls-available-p)
2274 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
2275 (setq elpher-use-tls nil)
2276 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
2277 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
2279 (defun elpher-view-raw ()
2280 "View raw server response for current page."
2282 (if (elpher-address-about-p (elpher-page-address elpher-current-page))
2283 (error "This page was not generated by a server")
2284 (elpher-visit-page elpher-current-page
2285 #'elpher-render-raw)))
2287 (defun elpher-back ()
2288 "Go to previous site."
2290 (elpher-visit-previous-page))
2292 (defun elpher-back-to-start ()
2293 "Go all the way back to the start page."
2295 (setq-local elpher-current-page nil)
2296 (setq-local elpher-history nil)
2297 (elpher-visit-page (elpher-make-start-page)))
2299 (defun elpher-download ()
2300 "Download the link at point."
2302 (let ((button (button-at (point))))
2304 (let ((page (button-get button 'elpher-page)))
2306 (error "Not an elpher page"))
2307 (when (elpher-address-about-p (elpher-page-address page))
2308 (error "Cannot download %s" (elpher-page-display-string page)))
2309 (elpher-visit-page (button-get button 'elpher-page)
2310 #'elpher-render-download))
2311 (error "No link selected"))))
2313 (defun elpher-download-current ()
2314 "Download the current page."
2316 (if (elpher-address-about-p (elpher-page-address elpher-current-page))
2317 (error "Cannot download %s"
2318 (elpher-page-display-string elpher-current-page))
2319 (elpher-visit-page (elpher-make-page
2320 (elpher-page-display-string elpher-current-page)
2321 (elpher-page-address elpher-current-page))
2322 #'elpher-render-download
2325 (defun elpher--build-link-map ()
2326 "Build alist mapping link names to destination pages in current buffer."
2327 (let ((link-map nil)
2328 (b (next-button (point-min) t)))
2330 (push (cons (button-label b) b) link-map)
2331 (setq b (next-button (button-start b))))
2334 (defun elpher-jump ()
2335 "Select a directory entry by name. Similar to the info browser (m)enu command."
2337 (let* ((link-map (elpher--build-link-map)))
2339 (let ((key (let ((completion-ignore-case t))
2340 (completing-read "Directory item/link: "
2342 (if (and key (> (length key) 0))
2343 (let ((b (cdr (assoc key link-map))))
2344 (goto-char (button-start b))
2345 (button-activate b)))))))
2347 (defun elpher-root-dir ()
2348 "Visit root of current server."
2350 (let ((address (elpher-page-address elpher-current-page)))
2351 (if (not (elpher-address-about-p address))
2352 (if (or (member (url-filename address) '("/" ""))
2353 (and (elpher-address-gopher-p address)
2354 (= (length (elpher-gopher-address-selector address)) 0)))
2355 (error "Already at root directory of current server")
2356 (let ((address-copy (elpher-address-from-url
2357 (elpher-address-to-url address))))
2358 (setf (url-filename address-copy) "")
2359 (elpher-go (elpher-address-to-url address-copy))))
2360 (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
2362 (defun elpher-info-page (page)
2363 "Display URL of PAGE in minibuffer."
2364 (let* ((address (elpher-page-address page))
2365 (url (elpher-address-to-url address))
2366 (iri (elpher-address-to-iri address)))
2369 (message "%s (Raw: %s)" iri url))))
2371 (defun elpher-info-link ()
2372 "Display information on page corresponding to link at point."
2374 (let ((button (button-at (point))))
2376 (error "No item selected"))
2377 (let ((page (button-get button 'elpher-page)))
2379 (error "Not an elpher page"))
2380 (elpher-info-page page))))
2382 (defun elpher-info-current ()
2383 "Display information on current page."
2385 (elpher-info-page elpher-current-page))
2387 (defun elpher-copy-page-url (page)
2388 "Copy URL representation of address of PAGE to `kill-ring'."
2389 (let* ((address (elpher-page-address page))
2390 (url (elpher-address-to-url address)))
2391 (message "Copied \"%s\" to kill-ring/clipboard." url)
2394 (defun elpher-copy-link-url ()
2395 "Copy URL of item at point to `kill-ring'."
2397 (let ((button (button-at (point))))
2399 (error "No item selected"))
2400 (let ((page (button-get button 'elpher-page)))
2402 (error "Not an elpher page"))
2403 (elpher-copy-page-url page))))
2405 (defun elpher-copy-current-url ()
2406 "Copy URL of current page to `kill-ring'."
2408 (elpher-copy-page-url elpher-current-page))
2410 (defun elpher-set-gopher-coding-system ()
2411 "Specify an explicit character coding system for gopher selectors."
2413 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
2414 (setq elpher-user-coding-system system)
2416 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
2417 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
2423 (defvar elpher-mode-map
2424 (let ((map (make-sparse-keymap)))
2425 (define-key map (kbd "TAB") 'elpher-next-link)
2426 (define-key map (kbd "<backtab>") 'elpher-prev-link)
2427 (define-key map (kbd "C-M-i") 'elpher-prev-link)
2428 (define-key map (kbd "u") 'elpher-back)
2429 (define-key map (kbd "-") 'elpher-back)
2430 (define-key map (kbd "^") 'elpher-back)
2431 (define-key map [mouse-3] 'elpher-back)
2432 (define-key map (kbd "U") 'elpher-back-to-start)
2433 (define-key map (kbd "g") 'elpher-go)
2434 (define-key map (kbd "o") 'elpher-go-current)
2435 (define-key map (kbd "O") 'elpher-root-dir)
2436 (define-key map (kbd "s") 'elpher-show-history)
2437 (define-key map (kbd "S") 'elpher-show-visited-pages)
2438 (define-key map (kbd "r") 'elpher-redraw)
2439 (define-key map (kbd "R") 'elpher-reload)
2440 (define-key map (kbd "T") 'elpher-toggle-tls)
2441 (define-key map (kbd ".") 'elpher-view-raw)
2442 (define-key map (kbd "d") 'elpher-download)
2443 (define-key map (kbd "D") 'elpher-download-current)
2444 (define-key map (kbd "m") 'elpher-jump)
2445 (define-key map (kbd "i") 'elpher-info-link)
2446 (define-key map (kbd "I") 'elpher-info-current)
2447 (define-key map (kbd "c") 'elpher-copy-link-url)
2448 (define-key map (kbd "C") 'elpher-copy-current-url)
2449 (define-key map (kbd "a") 'elpher-bookmark-link)
2450 (define-key map (kbd "A") 'elpher-bookmark-current)
2451 (define-key map (kbd "B") 'elpher-show-bookmarks)
2452 (define-key map (kbd "!") 'elpher-set-gopher-coding-system)
2453 (define-key map (kbd "F") 'elpher-forget-current-certificate)
2454 (when (fboundp 'evil-define-key*)
2457 (kbd "TAB") 'elpher-next-link
2458 (kbd "C-") 'elpher-follow-current-link
2459 (kbd "C-t") 'elpher-back
2460 (kbd "u") 'elpher-back
2461 (kbd "-") 'elpher-back
2462 (kbd "^") 'elpher-back
2463 [mouse-3] 'elpher-back
2464 (kbd "U") 'elpher-back-to-start
2465 (kbd "g") 'elpher-go
2466 (kbd "o") 'elpher-go-current
2467 (kbd "O") 'elpher-root-dir
2468 (kbd "s") 'elpher-show-history
2469 (kbd "S") 'elpher-show-visited-pages
2470 (kbd "r") 'elpher-redraw
2471 (kbd "R") 'elpher-reload
2472 (kbd "T") 'elpher-toggle-tls
2473 (kbd ".") 'elpher-view-raw
2474 (kbd "d") 'elpher-download
2475 (kbd "D") 'elpher-download-current
2476 (kbd "m") 'elpher-jump
2477 (kbd "i") 'elpher-info-link
2478 (kbd "I") 'elpher-info-current
2479 (kbd "c") 'elpher-copy-link-url
2480 (kbd "C") 'elpher-copy-current-url
2481 (kbd "a") 'elpher-bookmark-link
2482 (kbd "A") 'elpher-bookmark-current
2483 (kbd "B") 'elpher-show-bookmarks
2484 (kbd "!") 'elpher-set-gopher-coding-system
2485 (kbd "F") 'elpher-forget-current-certificate))
2487 "Keymap for gopher client.")
2489 (define-derived-mode elpher-mode special-mode "elpher"
2490 "Major mode for elpher, an elisp gopher client.
2492 This mode is automatically enabled by the interactive
2493 functions which initialize the client, namely
2494 `elpher', and `elpher-go'."
2495 (setq-local elpher-current-page nil)
2496 (setq-local elpher-history nil)
2497 (setq-local elpher-buffer-name (buffer-name))
2498 (setq-local bookmark-make-record-function #'elpher-bookmark-make-record)
2499 (setq-local imenu-create-index-function #'elpher-build-current-imenu-index))
2501 (when (fboundp 'evil-set-initial-state)
2502 (evil-set-initial-state 'elpher-mode 'motion))
2505 ;;; Main start procedure
2509 (defun elpher (&optional arg)
2510 "Start elpher with default landing page.
2511 The buffer used for Elpher sessions is determined by the value of
2512 ‘elpher-buffer-name’. If there is already an Elpher session active in
2513 that buffer, Emacs will simply switch to it. Otherwise, a new session
2514 will begin. A numeric prefix ARG (as in ‘\\[universal-argument] 42
2515 \\[execute-extended-command] elpher RET’) switches to the session with
2516 that number, creating it if necessary. A non numeric prefix ARG means
2517 to create a new session. Returns the buffer selected (or created)."
2519 (let* ((name (default-value 'elpher-buffer-name))
2520 (buf (cond ((numberp arg)
2521 (get-buffer-create (format "%s<%d>" name arg)))
2523 (generate-new-buffer name))
2525 (get-buffer-create name)))))
2526 (pop-to-buffer-same-window buf)
2527 (unless (buffer-modified-p)
2529 (elpher-visit-page (elpher-make-start-page))
2530 "Started Elpher."))); Otherwise (elpher) evaluates to start page string.
2532 ;;; elpher.el ends here