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 (spartan elpher-get-spartan-page elpher-render-spartan "spt" elpher-spartan)
95 (finger elpher-get-finger-page elpher-render-text "txt" elpher-text)
96 (telnet elpher-get-telnet-page nil "tel" elpher-telnet)
97 (other-url elpher-get-other-url-page nil "url" elpher-other-url)
98 (file elpher-get-file-page nil "~" elpher-gemini)
99 ((about welcome) elpher-get-welcome-page nil "E" elpher-index)
100 ((about bookmarks) elpher-get-bookmarks-page nil "E" elpher-index)
101 ((about history) elpher-get-history-page nil "E" elpher-index)
102 ((about visited-pages) elpher-get-visited-pages-page nil "E" elpher-index))
103 "Association list from types to getters, renderers, margin codes and index faces.")
106 ;;; Declarations to avoid compiler warnings.
110 (declare-function ansi-color-filter-apply "ansi-color")
111 (declare-function ansi-color-apply "ansi-color")
112 (declare-function bookmark-store "bookmark")
113 (declare-function org-link-store-props "ol")
114 (declare-function org-link-set-parameters "ol")
115 (defvar ansi-color-context)
116 (defvar xterm-color--current-fg)
117 (defvar xterm-color--current-bg)
118 (defvar bookmark-make-record-function)
119 (defvar mu4e~view-beginning-of-url-regexp)
120 (defvar eww-use-browse-url)
121 (defvar thing-at-point-uri-schemes))
124 ;;; Customization group
128 "A gopher and gemini client."
129 :group 'applications)
131 ;; General appearance and customizations
133 (defcustom elpher-open-urls-with-eww nil
134 "If non-nil, open URL selectors using eww.
135 Otherwise, use the system browser via the `browse-url' function."
138 (defcustom elpher-use-header t
139 "If non-nil, display current page information in buffer header."
142 (defcustom elpher-auto-disengage-TLS nil
143 "If non-nil, automatically disengage TLS following an unsuccessful connection.
144 While enabling this may seem convenient, it is also potentially
145 dangerous as it allows switching from an encrypted channel back to
146 plain text without user input."
149 (defcustom elpher-connection-timeout 5
150 "Specifies the number of seconds to wait for a network connection to time out."
153 (defcustom elpher-filter-ansi-from-text nil
154 "If non-nil, filter ANSI escape sequences from text.
155 The default behaviour is to use the ansi-color package (or xterm-color if it is
156 available) to interpret these sequences."
159 (defcustom elpher-certificate-directory
160 (file-name-as-directory (locate-user-emacs-file "elpher-certificates"))
161 "Specify the name of the directory where client certificates will be stored.
162 These certificates may be used for establishing authenticated TLS connections."
165 (defcustom elpher-openssl-command "openssl"
166 "The command used to launch openssl when generating TLS client certificates."
169 (defcustom elpher-default-url-type "gopher"
170 "Default URL type (i.e. scheme) to assume if not explicitly given."
171 :type '(choice (const "gopher")
174 (defcustom elpher-gemini-TLS-cert-checks nil
175 "If non-nil, verify gemini server TLS certs using the default security level.
176 Otherwise, certificate verification is disabled.
178 This defaults to off because it is standard practice for Gemini servers
179 to use self-signed certificates, meaning that most servers provide what
180 EMACS considers to be an invalid certificate."
183 (defcustom elpher-gemini-max-fill-width 80
184 "Specify the maximum default width (in columns) of text/gemini documents.
185 The actual width used is the minimum of this value and the window width at
186 the time when the text is rendered."
189 (defcustom elpher-gemini-link-string "→ "
190 "Specify the string used to indicate links when rendering gemini maps.
194 (defcustom elpher-gemini-bullet-string "•"
195 "Specify the string used for bullets when rendering gemini maps."
198 (defcustom elpher-ipv4-always nil
199 "If non-nil, elpher will always use IPv4 to establish network connections.
200 This can be useful when browsing from a computer that supports IPv6, because
201 some servers which do not support IPv6 can take a long time to time-out."
204 (defcustom elpher-socks-always nil
205 "If non-nil, elpher will establish network connections over a SOCKS proxy.
206 Otherwise, the SOCKS proxy is only used for connections to onion services."
209 (defcustom elpher-use-emacs-bookmark-menu nil
210 "If non-nil, elpher will only use the native Emacs bookmark menu.
211 Otherwise, \\[elpher-show-bookmarks] will visit a special elpher bookmark
212 page within which all of the standard elpher keybindings are active."
215 (defcustom elpher-start-page-url "about:welcome"
216 "Specify the page displayed initially by elpher.
217 The default welcome screen is \"about:welcome\", while the bookmarks list
218 is \"about:bookmarks\". You can also specify local files via \"file:\".
220 Beware that using \"about:bookmarks\" as a start page in combination with
221 the `elpher-use-bookmark-menu' variable set to non-nil will prevent the
222 Emacs bookmark menu being accessible via \\[elpher-show-bookmarks] from
226 (defcustom elpher-gemini-hide-preformatted nil
227 "Cause elpher to hide preformatted gemini text by default.
228 When this option is enabled, preformatted text in text/gemini documents
229 is replaced with a button which can be used to toggle its display.
231 This is intended to improve accessibility, as preformatted text often
232 includes art which can be difficult for screen readers to interpret
236 (defcustom elpher-gemini-preformatted-toggle-bullet "‣ "
237 "Margin symbol used to distinguish the preformatted text toggle."
240 (defcustom elpher-gemini-preformatted-toggle-label "[Toggle Preformatted Text]"
241 "Label of button used to toggle formatted text."
244 ;; Face customizations
246 (defgroup elpher-faces nil
247 "Elpher face customizations."
250 (defface elpher-index
251 '((t :inherit font-lock-keyword-face))
252 "Face used for directory type directory records.")
256 "Face used for text type directory records.")
259 '((t :inherit default))
260 "Face used for info type directory records.")
262 (defface elpher-image
263 '((t :inherit font-lock-string-face))
264 "Face used for image type directory records.")
266 (defface elpher-search
267 '((t :inherit warning))
268 "Face used for search type directory records.")
271 '((t :inherit font-lock-comment-face))
272 "Face used for html type directory records.")
274 (defface elpher-gemini
275 '((t :inherit font-lock-constant-face))
276 "Face used for Gemini type directory records.")
278 (defface elpher-spartan
279 '((t :inherit font-lock-constant-face))
280 "Face used for Spartan type directory records.")
282 (defface elpher-other-url
283 '((t :inherit font-lock-comment-face))
284 "Face used for other URL type links records.")
286 (defface elpher-telnet
287 '((t :inherit font-lock-function-name-face))
288 "Face used for telnet type directory records.")
290 (defface elpher-binary
291 '((t :inherit font-lock-doc-face))
292 "Face used for binary type directory records.")
294 (defface elpher-unknown
295 '((t :inherit error))
296 "Face used for directory records with unknown/unsupported types.")
298 (defface elpher-margin-key
300 "Face used for directory margin key.")
302 (defface elpher-margin-brackets
303 '((t :inherit shadow))
304 "Face used for brackets around directory margin key.")
306 (defface elpher-gemini-heading1
307 '((t :inherit bold :height 1.8))
308 "Face used for gemini heading level 1.")
310 (defface elpher-gemini-heading2
311 '((t :inherit bold :height 1.5))
312 "Face used for gemini heading level 2.")
314 (defface elpher-gemini-heading3
315 '((t :inherit bold :height 1.2))
316 "Face used for gemini heading level 3.")
318 (defface elpher-gemini-quoted
319 '((t :inherit font-lock-doc-face))
320 "Face used for gemini quoted texts.")
322 (defface elpher-gemini-preformatted-toggle
323 '((t :inherit button))
324 "Face used for buttons used to toggle display of preformatted text.")
331 ;; An elpher "address" object is either a url object or a symbol.
332 ;; Addresses with the "about" type, corresponding to pages generated
333 ;; dynamically for and by elpher. All others represent pages which
334 ;; rely on content retrieved over the network.
336 (defun elpher-address-from-url (url-string &optional default-scheme)
337 "Create a ADDRESS object corresponding to the given URL-STRING.
338 If DEFAULT-SCHEME is non-nil, this sets the scheme of the URL when one
339 is not explicitly given."
340 (let ((data (match-data))) ; Prevent parsing clobbering match data
342 (let ((url (url-generic-parse-url url-string)))
343 (unless (and (not (url-fullness url)) (url-type url))
344 (unless (url-type url)
345 (setf (url-type url) default-scheme))
346 (unless (url-host url)
347 (let ((p (split-string (url-filename url) "/" nil nil)))
348 (setf (url-host url) (car p))
349 (setf (url-filename url)
351 (concat "/" (mapconcat #'identity (cdr p) "/"))
353 (when (not (string-empty-p (url-host url)))
354 (setf (url-fullness url) t)
355 (setf (url-host url) (puny-encode-domain (url-host url))))
356 (when (or (equal "gopher" (url-type url))
357 (equal "gophers" (url-type url)))
359 (when (or (equal (url-filename url) "")
360 (equal (url-filename url) "/"))
361 (setf (url-filename url) "/1")))
362 (when (equal "gemini" (url-type url))
364 (if (equal (url-filename url) "")
365 (setf (url-filename url) "/"))))
366 (elpher-remove-redundant-ports url))
367 (set-match-data data))))
369 (defun elpher-remove-redundant-ports (address)
370 "Remove redundant port specifiers from ADDRESS.
371 Here 'redundant' means that the specified port matches the default
372 for that protocol, eg 70 for gopher."
373 (if (and (not (elpher-address-about-p address))
374 (eq (url-portspec address) ; (url-port) is too slow!
375 (pcase (url-type address)
377 ((or "gopher" "gophers") 70)
380 (setf (url-portspec address) nil))
383 (defun elpher-make-gopher-address (type selector host port &optional tls)
384 "Create an ADDRESS object using gopher directory record attributes.
385 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
386 If the optional attribute TLS is non-nil, the address will be marked as
387 requiring gopher-over-TLS."
389 ((equal type ?i) nil)
390 ((and (equal type ?h)
391 (string-prefix-p "URL:" selector))
392 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
394 (elpher-address-from-url
397 ":" (number-to-string port))))
399 (elpher-address-from-url
400 (concat "gopher" (if tls "s" "")
402 ":" (number-to-string port)
406 (defun elpher-make-about-address (type)
407 "Create an ADDRESS object corresponding to the given about address TYPE."
408 (elpher-address-from-url (concat "about:" (symbol-name type))))
410 (defun elpher-address-to-url (address)
411 "Get string representation of ADDRESS."
412 (url-encode-url (url-recreate-url address)))
414 (defun elpher-address-type (address)
415 "Retrieve type of ADDRESS object.
416 This is used to determine how to retrieve and render the document the
417 address refers to, via the table `elpher-type-map'."
418 (pcase (url-type address)
420 (list 'about (intern (url-filename address))))
421 ((or "gopher" "gophers")
423 (if (member (url-filename address) '("" "/"))
425 (string-to-char (substring (url-filename address) 1)))))
432 (defun elpher-address-about-p (address)
433 "Return non-nil if ADDRESS is an about address."
434 (pcase (elpher-address-type address) (`(about ,_) t)))
436 (defun elpher-address-gopher-p (address)
437 "Return non-nill if ADDRESS object is a gopher address."
438 (pcase (elpher-address-type address) (`(gopher ,_) t)))
440 (defun elpher-address-protocol (address)
441 "Retrieve the transport protocol for ADDRESS."
444 (defun elpher-address-filename (address)
445 "Retrieve the filename component of ADDRESS.
446 For gopher addresses this is a combination of the selector type and selector."
447 (url-unhex-string (url-filename address)))
449 (defun elpher-address-host (address)
450 "Retrieve host from ADDRESS object."
451 (let ((host-pre (url-host address)))
452 ;; The following strips out square brackets which sometimes enclose IPv6
453 ;; addresses. Doing this here rather than at the parsing stage may seem
454 ;; weird, but this lets us way we avoid having to muck with both URL parsing
455 ;; and reconstruction. It's also more efficient, as this method is not
456 ;; called during page rendering.
457 (if (and (> (length host-pre) 2)
458 (eq (elt host-pre 0) ?\[)
459 (eq (elt host-pre (- (length host-pre) 1)) ?\]))
460 (substring host-pre 1 (- (length host-pre) 1))
463 (defun elpher-address-user (address)
464 "Retrieve user from ADDRESS object."
467 (defun elpher-address-port (address)
468 "Retrieve port from ADDRESS object.
469 If no address is defined, returns 0. (This is for compatibility with
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 ;;; Processing text for display
753 (defun elpher-process-text-for-display (string)
754 "Perform any desired processing of STRING prior to display as text.
755 Currently includes buttonifying URLs and processing ANSI escape codes."
756 (elpher-buttonify-urls (if elpher-filter-ansi-from-text
757 (elpher-color-filter-apply string)
758 (elpher-color-apply string))))
761 ;;; Network error reporting
764 (defun elpher-network-error (address error)
765 "Display ERROR message following unsuccessful negotiation with ADDRESS.
766 ERROR can be either an error object or a string."
767 (elpher-with-clean-buffer
768 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
769 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
770 (if (stringp error) error (error-message-string error)) "\n"
771 (propertize "\n----------------\n\n" 'face 'error)
772 "Press 'u' to return to the previous page.")))
775 ;;; General network communication
778 (defvar elpher-network-timer nil
779 "Timer used for network connections.")
781 (defvar elpher-use-tls nil
782 "If non-nil, use TLS to communicate with gopher servers.")
784 (defvar elpher-client-certificate nil
785 "If non-nil, contains client certificate details to use for TLS connections.")
787 (defun elpher-process-cleanup ()
788 "Immediately shut down any extant elpher process and timers."
789 (let ((p (get-process "elpher-process")))
790 (if p (delete-process p)))
791 (if (timerp elpher-network-timer)
792 (cancel-timer elpher-network-timer)))
794 (defun elpher-make-network-timer (thunk)
795 "Create a timer to run the THUNK after `elpher-connection-timeout' seconds.
796 This is just a wraper around `run-at-time' which additionally sets the
797 buffer-local variable `elpher-network-timer' to allow
798 `elpher-process-cleanup' to also clear the timer."
799 (let ((timer (run-at-time elpher-connection-timeout nil thunk)))
800 (setq-local elpher-network-timer timer)
803 (defun elpher-get-host-response (address default-port query-string response-processor
804 &optional use-tls force-ipv4)
805 "Generic function for retrieving data from ADDRESS.
807 When ADDRESS lacks a specific port, DEFAULT-PORT is used instead.
808 QUERY-STRING is a string sent to the host specified by ADDRESS to
809 illicet a response. This response is passed as an argument to the
810 function RESPONSE-PROCESSOR.
812 If non-nil, USE-TLS specifies that the connection is to be made over
813 TLS. If set to gemini, the certificate verification will be disabled
814 unless `elpher-gemini-TLS-cert-checks' is non-nil.
816 If non-nil, FORCE-IPV4 causes the network connection to be made over
817 ipv4 only. (The default behaviour when this is not set depends on
818 the host operating system and the local network capabilities.)"
819 (if (and use-tls (not (gnutls-available-p)))
820 (error "Use of TLS requires Emacs to be compiled with GNU TLS support")
821 (unless (< (elpher-address-port address) 65536)
822 (error "Cannot establish network connection: port number > 65536"))
823 (when (and (eq use-tls 'gemini) (not elpher-gemini-TLS-cert-checks))
824 (setq-local network-security-level 'low)
825 (setq-local gnutls-verify-error nil))
827 (let* ((kill-buffer-query-functions nil)
828 (port (elpher-address-port address))
829 (host (elpher-address-host address))
830 (service (if (> port 0) port default-port))
831 (response-string-parts nil)
834 (socks (or elpher-socks-always (string-suffix-p ".onion" host)))
835 (gnutls-params (list :type 'gnutls-x509pki
838 (elpher-get-current-keylist address)))
839 (timer (elpher-make-network-timer
841 (elpher-process-cleanup)
843 ; Try again with IPv4
844 ((not (or elpher-ipv4-always force-ipv4 socks))
845 (message "Connection timed out. Retrying with IPv4.")
846 (elpher-get-host-response address default-port
851 (not (eq use-tls 'gemini))
852 (or elpher-auto-disengage-TLS
854 "TLS connetion failed. Disable TLS mode and retry? ")))
855 (setq elpher-use-tls nil)
856 (elpher-get-host-response address default-port
861 (elpher-network-error address "Connection time-out."))))))
862 (proc (if socks (socks-open-network-stream "elpher-process" nil host service)
863 (make-network-process :name "elpher-process"
865 :family (and (or force-ipv4
873 (cons 'gnutls-x509pki
874 (apply #'gnutls-boot-parameters
876 (setq elpher-network-timer timer)
877 (set-process-coding-system proc 'binary 'binary)
878 (set-process-query-on-exit-flag proc nil)
879 (elpher-buffer-message (concat "Connecting to " host "..."
880 " (press 'u' to abort)"))
881 (set-process-filter proc
882 (lambda (_proc string)
886 (setq bytes-received (+ bytes-received (length string)))
887 (let ((new-hkbytes-received (/ bytes-received 102400)))
888 (when (> new-hkbytes-received hkbytes-received)
889 (setq hkbytes-received new-hkbytes-received)
890 (elpher-buffer-message
892 (number-to-string (/ hkbytes-received 10.0))
895 (setq response-string-parts
896 (cons string response-string-parts))))
897 (set-process-sentinel proc
900 (cancel-timer timer))
901 (condition-case the-error
903 ((string-prefix-p "open" event) ; request URL
904 (elpher-buffer-message
905 (concat "Connected to " host ". Receiving data..."
906 " (press 'u' to abort)"))
907 (let ((inhibit-eol-conversion t))
908 (process-send-string proc query-string)))
909 ((string-prefix-p "deleted" event)) ; do nothing
910 ((and (not response-string-parts)
911 (not (or elpher-ipv4-always force-ipv4 socks)))
912 ; Try again with IPv4
913 (message "Connection failed. Retrying with IPv4.")
914 (elpher-get-host-response address default-port
918 (response-string-parts
919 (elpher-with-clean-buffer
920 (insert "Data received. Rendering..."))
921 (funcall response-processor
922 (apply #'concat (reverse response-string-parts)))
923 (elpher-restore-pos))
925 (error "No response from server")))
927 (elpher-network-error address the-error)))))
929 (if use-tls (apply #'gnutls-negotiate :process proc gnutls-params))
930 (funcall (process-sentinel proc) proc "open\n")))
932 (elpher-process-cleanup)
933 (error "Error initiating connection to server")))))
936 ;;; Client-side TLS Certificate Management
939 (defun elpher-generate-certificate (common-name key-file cert-file &optional temporary)
940 "Generate a key and a self-signed client TLS certificate using openssl.
942 The Common Name field of the certificate is set to COMMON-NAME. The
943 arguments KEY-FILE and CERT-FILE should contain the absolute paths of
944 the key and certificate files to write.
946 If TEMPORARY is non-nil, the certificate will be given an exporation
947 period of one day, and the key and certificate files will be deleted
948 when the certificate is no longer needed for the current session.
950 Otherwise, the certificate will be given a 100 year expiration period
951 and the files will not be deleted.
953 The function returns a list containing the current host name, the
954 temporary flag, and the key and cert file names in the form required
955 by `gnutls-boot-parameters`."
956 (let ((exp-key-file (expand-file-name key-file))
957 (exp-cert-file (expand-file-name cert-file)))
960 (call-process elpher-openssl-command nil nil nil
961 "req" "-x509" "-newkey" "rsa:2048"
962 "-days" (if temporary "1" "36500")
964 "-subj" (concat "/CN=" common-name)
965 "-keyout" exp-key-file
966 "-out" exp-cert-file)
967 (list (elpher-address-host (elpher-page-address elpher-current-page))
968 temporary exp-key-file exp-cert-file))
970 (message "Check that openssl is installed, or customize `elpher-openssl-command`.")
971 (error "Program 'openssl', required for certificate generation, not found")))))
973 (defun elpher-generate-throwaway-certificate ()
974 "Generate and return details of a throwaway certificate.
975 The key and certificate files will be deleted when they are no
976 longer needed for this session."
977 (let* ((file-base (make-temp-name "elpher"))
978 (key-file (concat temporary-file-directory file-base ".key"))
979 (cert-file (concat temporary-file-directory file-base ".crt")))
980 (elpher-generate-certificate file-base key-file cert-file t)))
982 (defun elpher-generate-persistent-certificate (file-base common-name)
983 "Generate and return details of a persistent certificate.
984 The argument FILE-BASE is used as the base for the key and certificate
985 files, while COMMON-NAME specifies the common name field of the
988 The key and certificate files are written to in `elpher-certificate-directory'."
989 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
990 (cert-file (concat elpher-certificate-directory file-base ".crt")))
991 (elpher-generate-certificate common-name key-file cert-file)))
993 (defun elpher-get-existing-certificate (file-base)
994 "Return a certificate object corresponding to an existing certificate.
995 It is assumed that the key files FILE-BASE.key and FILE-BASE.crt exist in
996 the directory `elpher-certificate-directory'."
997 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
998 (cert-file (concat elpher-certificate-directory file-base ".crt")))
999 (list (elpher-address-host (elpher-page-address elpher-current-page))
1001 (expand-file-name key-file)
1002 (expand-file-name cert-file))))
1004 (defun elpher-install-and-use-existing-certificate (key-file-src cert-file-src file-base)
1005 "Install a key+certificate file pair in `elpher-certificate-directory'.
1006 The strings KEY-FILE-SRC and CERT-FILE-SRC are the existing key and
1007 certificate files to install. The argument FILE-BASE is used as the
1008 base for the installed key and certificate files."
1009 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
1010 (cert-file (concat elpher-certificate-directory file-base ".crt")))
1011 (if (or (file-exists-p key-file)
1012 (file-exists-p cert-file))
1013 (error "A certificate with base name %s is already installed" file-base))
1014 (copy-file key-file-src key-file)
1015 (copy-file cert-file-src cert-file)
1016 (list (elpher-address-host (elpher-page-address elpher-current-page))
1018 (expand-file-name key-file)
1019 (expand-file-name cert-file))))
1021 (defun elpher-list-existing-certificates ()
1022 "Return a list of the persistent certificates in `elpher-certificate-directory'."
1023 (unless (file-directory-p elpher-certificate-directory)
1024 (make-directory elpher-certificate-directory))
1027 (file-name-sans-extension file))
1028 (directory-files elpher-certificate-directory nil "\\.key$")))
1030 (defun elpher-forget-current-certificate ()
1031 "Causes any current certificate to be forgotten.)
1032 In the case of throwaway certificates, the key and certificate files
1035 (when elpher-client-certificate
1036 (unless (and (called-interactively-p 'any)
1037 (not (y-or-n-p (concat "Really forget client certificate? "
1038 "(Throwaway certificates will be deleted.)"))))
1039 (when (cadr elpher-client-certificate)
1040 (delete-file (elt elpher-client-certificate 2))
1041 (delete-file (elt elpher-client-certificate 3)))
1042 (setq elpher-client-certificate nil)
1043 (if (called-interactively-p 'any)
1044 (message "Client certificate forgotten.")))))
1046 (defun elpher-get-current-keylist (address)
1047 "Retrieve the `gnutls-boot-parameters'-compatable keylist.
1049 This is obtained from the client certificate described by
1050 `elpher-current-certificate', if one is available and the host for
1051 that certificate matches the host in ADDRESS.
1053 If `elpher-current-certificate' is non-nil, and its host name doesn't
1054 match that of ADDRESS, the certificate is forgotten."
1055 (if elpher-client-certificate
1056 (if (string= (car elpher-client-certificate)
1057 (elpher-address-host address))
1058 (list (cddr elpher-client-certificate))
1059 (elpher-forget-current-certificate)
1060 (message "Disabling client certificate for new host")
1065 ;;; Gopher selector retrieval
1068 (defun elpher-get-gopher-response (address renderer)
1069 "Get response string from gopher server at ADDRESS and render using RENDERER."
1070 (elpher-get-host-response address 70
1071 (concat (elpher-gopher-address-selector address) "\r\n")
1073 (or (string= (elpher-address-protocol address) "gophers")
1076 (defun elpher-get-gopher-page (renderer)
1077 "Getter function for gopher pages.
1078 The RENDERER procedure is used to display the contents of the page
1079 once they are retrieved from the gopher server."
1080 (let* ((address (elpher-page-address elpher-current-page))
1081 (content (elpher-get-cached-content address)))
1082 (if (and content (funcall renderer nil))
1083 (elpher-with-clean-buffer
1085 (elpher-restore-pos))
1086 (elpher-with-clean-buffer
1087 (insert "LOADING... (use 'u' to cancel)\n"))
1088 (condition-case the-error
1089 (elpher-get-gopher-response address renderer)
1091 (elpher-network-error address the-error))))))
1095 (defun elpher-insert-margin (&optional type-name)
1096 "Insert index margin, optionally containing the TYPE-NAME, into current buffer."
1099 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
1101 (propertize "[" 'face 'elpher-margin-brackets)
1102 (propertize type-name 'face 'elpher-margin-key)
1103 (propertize "]" 'face 'elpher-margin-brackets))))
1105 (insert (make-string elpher-margin-width ?\s))))
1107 (defun elpher--page-button-help (_window buffer pos)
1108 "Function called by Emacs to generate mouse-over text.
1109 The arguments specify the BUFFER and the POS within the buffer of the item
1110 for which help is required. The function returns the help to be
1111 displayed. The _WINDOW argument is currently unused."
1112 (with-current-buffer buffer
1113 (let ((button (button-at pos)))
1115 (let* ((page (button-get button 'elpher-page))
1116 (address (elpher-page-address page)))
1117 (format "mouse-1, RET: open '%s'" (elpher-address-to-url address)))))))
1119 (defun elpher-insert-index-record (display-string &optional address)
1120 "Function to insert an index record into the current buffer.
1121 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
1122 If ADDRESS is not supplied or nil the record is rendered as an
1123 'information' line."
1124 (let* ((type (if address (elpher-address-type address) nil))
1125 (type-map-entry (cdr (assoc type elpher-type-map))))
1127 (let* ((margin-code (elt type-map-entry 2))
1128 (face (elt type-map-entry 3))
1129 (filtered-display-string (elpher-color-filter-apply display-string))
1130 (page (elpher-make-page filtered-display-string address)))
1131 (elpher-insert-margin margin-code)
1132 (insert-text-button filtered-display-string
1135 'action #'elpher-click-link
1137 'help-echo #'elpher--page-button-help))
1139 ('nil ;; Information
1140 (elpher-insert-margin)
1141 (let ((propertized-display-string
1142 (propertize display-string 'face 'elpher-info)))
1143 (insert (elpher-process-text-for-display propertized-display-string))))
1144 (`(gopher ,selector-type) ;; Unknown
1145 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
1146 (insert (propertize display-string
1147 'face 'elpher-unknown)))))
1150 (defun elpher-click-link (button)
1151 "Function called when the gopher link BUTTON is activated."
1152 (let ((page (button-get button 'elpher-page)))
1153 (elpher-visit-page page)))
1155 (defun elpher-render-index (data &optional _mime-type-string)
1156 "Render DATA as an index. MIME-TYPE-STRING is unused."
1157 (elpher-with-clean-buffer
1160 (let ((data-processed (elpher-preprocess-text-response data)))
1161 (dolist (line (split-string data-processed "\n"))
1163 (unless (= (length line) 0)
1164 (let* ((type (elt line 0))
1165 (fields (split-string (substring line 1) "\t"))
1166 (display-string (elt fields 0))
1167 (selector (elt fields 1))
1168 (host (elt fields 2))
1169 (port (if (elt fields 3)
1170 (string-to-number (elt fields 3))
1172 (address (elpher-make-gopher-address type selector host port)))
1173 (elpher-insert-index-record display-string address))))))
1174 (elpher-cache-content (elpher-page-address elpher-current-page)
1179 (defun elpher-render-text (data &optional _mime-type-string)
1180 "Render DATA as text. MIME-TYPE-STRING is unused."
1181 (elpher-with-clean-buffer
1184 (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
1185 (elpher-cache-content
1186 (elpher-page-address elpher-current-page)
1191 (defun elpher-render-image (data &optional _mime-type-string)
1192 "Display DATA as image. MIME-TYPE-STRING is unused."
1195 (if (display-images-p)
1196 (let* ((image (create-image
1200 (error "Unsupported image format")
1201 (let ((window (get-buffer-window elpher-buffer-name)))
1203 (setf (image-property image :max-width) (window-body-width window t))
1204 (setf (image-property image :max-height) (window-body-height window t))))
1205 (elpher-with-clean-buffer
1206 (insert-image image)
1207 (elpher-restore-pos))))
1208 (elpher-render-download data))))
1210 ;; Search retrieval and rendering
1212 (defun elpher-get-gopher-query-page (renderer)
1213 "Getter for gopher addresses requiring input.
1214 The response is rendered using the rendering function RENDERER."
1215 (let* ((address (elpher-page-address elpher-current-page))
1216 (content (elpher-get-cached-content address))
1218 (if (and content (funcall renderer nil))
1219 (elpher-with-clean-buffer
1221 (elpher-restore-pos)
1222 (message "Displaying cached search results. Reload to perform a new search."))
1224 (let* ((query-string (read-string "Query: "))
1225 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
1226 (search-address (elpher-make-gopher-address ?1
1228 (elpher-address-host address)
1229 (elpher-address-port address)
1230 (equal (elpher-address-type address) "gophers"))))
1233 (elpher-with-clean-buffer
1234 (insert "LOADING RESULTS... (use 'u' to cancel)"))
1235 (elpher-get-gopher-response search-address renderer))
1237 (elpher-visit-previous-page))))))
1239 ;; Raw server response rendering
1241 (defun elpher-render-raw (data &optional mime-type-string)
1242 "Display raw DATA in buffer. MIME-TYPE-STRING is also displayed if provided."
1245 (elpher-with-clean-buffer
1246 (when mime-type-string
1247 (insert "MIME type specified by server: '" mime-type-string "'\n"))
1249 (goto-char (point-min)))
1250 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
1252 ;; File save "rendering"
1254 (defun elpher-render-download (data &optional _mime-type-string)
1255 "Save DATA to file. MIME-TYPE-STRING is unused."
1258 (let* ((address (elpher-page-address elpher-current-page))
1259 (selector (if (elpher-address-gopher-p address)
1260 (elpher-gopher-address-selector address)
1261 (elpher-address-filename address))))
1262 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1263 (let* ((filename-proposal (file-name-nondirectory selector))
1264 (filename (read-file-name "Download complete. Save file as: "
1266 (if (> (length filename-proposal) 0)
1269 (let ((coding-system-for-write 'binary))
1270 (with-temp-file filename
1272 (message (format "Saved to file %s." filename))))))
1276 (defun elpher-render-html (data &optional _mime-type-string)
1277 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
1278 (elpher-with-clean-buffer
1281 (let ((dom (with-temp-buffer
1283 (libxml-parse-html-region (point-min) (point-max)))))
1284 (shr-insert-document dom)))))
1286 ;; Gemini page retrieval
1288 (defvar elpher-gemini-redirect-chain)
1290 (defun elpher-get-gemini-response (address renderer)
1291 "Get response string from gemini server at ADDRESS and render using RENDERER."
1292 (elpher-get-host-response address 1965
1293 (concat (elpher-address-to-url address) "\r\n")
1294 (lambda (response-string)
1295 (elpher-process-gemini-response response-string renderer))
1298 (defun elpher-parse-gemini-response (response)
1299 "Parse the RESPONSE string and return a list of components.
1300 The list is of the form (code meta body). A response of nil implies
1301 that the response was malformed."
1302 (let ((header-end-idx (string-match "\r\n" response)))
1304 (let ((header (string-trim (substring response 0 header-end-idx)))
1305 (body (substring response (+ header-end-idx 2))))
1306 (if (>= (length header) 2)
1307 (let ((code (substring header 0 2))
1308 (meta (string-trim (substring header 2))))
1309 (list code meta body))
1310 (error "Malformed response: No response status found in header %s" header)))
1311 (error "Malformed response: No CRLF-delimited header found in response %s" response))))
1313 (defun elpher-process-gemini-response (response-string renderer)
1314 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
1315 (let ((response-components (elpher-parse-gemini-response response-string)))
1316 (let ((response-code (elt response-components 0))
1317 (response-meta (elt response-components 1))
1318 (response-body (elt response-components 2)))
1319 (pcase (elt response-code 0)
1320 (?1 ; Input required
1321 (elpher-with-clean-buffer
1322 (insert "Gemini server is requesting input."))
1323 (let* ((query-string
1324 (if (eq (elt response-code 1) ?1)
1325 (read-passwd (concat response-meta ": "))
1326 (read-string (concat response-meta ": "))))
1327 (query-address (seq-copy (elpher-page-address elpher-current-page)))
1328 (old-fname (url-filename query-address)))
1329 (setf (url-filename query-address)
1330 (concat old-fname "?" (url-build-query-string `((,query-string)))))
1331 (elpher-get-gemini-response query-address renderer)))
1332 (?2 ; Normal response
1333 (funcall renderer response-body response-meta))
1335 (message "Following redirect to %s" response-meta)
1336 (if (>= (length elpher-gemini-redirect-chain) 5)
1337 (error "More than 5 consecutive redirects followed"))
1338 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
1339 (if (member redirect-address elpher-gemini-redirect-chain)
1340 (error "Redirect loop detected"))
1341 (if (not (eq (elpher-address-type redirect-address) 'gemini))
1342 (error "Server tried to automatically redirect to non-gemini URL: %s"
1344 (elpher-page-set-address elpher-current-page redirect-address)
1345 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
1346 (elpher-get-gemini-response redirect-address renderer)))
1347 (?4 ; Temporary failure
1348 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
1349 response-code response-meta))
1350 (?5 ; Permanent failure
1351 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
1352 response-code response-meta))
1353 (?6 ; Client certificate required
1354 (elpher-with-clean-buffer
1355 (if elpher-client-certificate
1356 (insert "Gemini server does not recognise the provided TLS certificate:\n\n")
1357 (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
1359 (elpher-gemini-insert-text response-meta))
1360 (let ((chosen-certificate (elpher-choose-client-certificate)))
1361 (unless chosen-certificate
1362 (error "Gemini server requires a client certificate and none was provided"))
1363 (setq elpher-client-certificate chosen-certificate))
1364 (elpher-with-clean-buffer)
1365 (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer))
1367 (error "Gemini server response unknown: %s %s"
1368 response-code response-meta))))))
1370 (defun elpher--read-answer-polyfill (question answers)
1371 "Polyfill for `read-answer' in Emacs 26.1.
1372 QUESTION is a string containing a question, and ANSWERS
1373 is a list of possible answers."
1374 (completing-read question (mapcar 'identity answers)))
1376 (if (fboundp 'read-answer)
1377 (defalias 'elpher-read-answer 'read-answer)
1378 (defalias 'elpher-read-answer 'elpher--read-answer-polyfill))
1380 (defun elpher-choose-client-certificate ()
1381 "Prompt for a client certificate to use to establish a TLS connection."
1382 (let* ((read-answer-short t))
1383 (pcase (read-answer "What do you want to do? "
1385 "generate and use throw-away certificate")
1387 "generate new or use existing persistent certificate")
1389 "stop immediately")))
1391 (setq elpher-client-certificate (elpher-generate-throwaway-certificate)))
1393 (let* ((existing-certificates (elpher-list-existing-certificates))
1394 (file-base (completing-read
1395 "Nickname for new or existing certificate (autocompletes, empty response aborts): "
1396 existing-certificates)))
1397 (if (string-empty-p (string-trim file-base))
1399 (if (member file-base existing-certificates)
1400 (setq elpher-client-certificate
1401 (elpher-get-existing-certificate file-base))
1402 (pcase (read-answer "Generate new certificate or install externally-generated one? "
1404 "generate new certificate")
1406 "install existing certificate")
1408 "stop immediately")))
1410 (let ((common-name (read-string "Common Name field for new certificate: "
1412 (message "New key and self-signed certificate written to %s"
1413 elpher-certificate-directory)
1414 (elpher-generate-persistent-certificate file-base common-name)))
1416 (let* ((cert-file (read-file-name "Certificate file: " nil nil t))
1417 (key-file (read-file-name "Key file: " nil nil t)))
1418 (message "Key and certificate installed in %s for future use"
1419 elpher-certificate-directory)
1420 (elpher-install-and-use-existing-certificate key-file
1426 (defun elpher-get-gemini-page (renderer)
1427 "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
1428 (let* ((address (elpher-page-address elpher-current-page))
1429 (content (elpher-get-cached-content address)))
1430 (condition-case the-error
1431 (if (and content (funcall renderer nil))
1432 (elpher-with-clean-buffer
1434 (elpher-restore-pos))
1435 (elpher-with-clean-buffer
1436 (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
1437 (setq elpher-gemini-redirect-chain nil)
1438 (elpher-get-gemini-response address renderer))
1440 (elpher-network-error address the-error)))))
1442 (defun elpher-render-gemini (body &optional mime-type-string)
1443 "Render gemini response BODY with rendering MIME-TYPE-STRING."
1446 (let* ((mime-type-string* (if (or (not mime-type-string)
1447 (string-empty-p mime-type-string))
1448 "text/gemini; charset=utf-8"
1450 (mime-type-split (split-string mime-type-string* ";" t))
1451 (mime-type (string-trim (car mime-type-split)))
1452 (parameters (mapcar (lambda (s)
1453 (let ((key-val (split-string s "=")))
1454 (list (downcase (string-trim (car key-val)))
1455 (downcase (string-trim (cadr key-val))))))
1456 (cdr mime-type-split))))
1457 (when (string-prefix-p "text/" mime-type)
1458 (setq body (decode-coding-string
1460 (if (assoc "charset" parameters)
1461 (intern (cadr (assoc "charset" parameters)))
1463 (setq body (replace-regexp-in-string "\r" "" body)))
1465 ((or "text/gemini" "")
1466 (elpher-render-gemini-map body parameters))
1468 (elpher-render-html body))
1469 ((pred (string-prefix-p "text/"))
1470 (elpher-render-gemini-plain-text body parameters))
1471 ((pred (string-prefix-p "image/"))
1472 (elpher-render-image body))
1474 (elpher-render-download body))))))
1476 (defun elpher-gemini-get-link-url (link-line)
1477 "Extract the url portion of LINK-LINE, a gemini map file link line.
1478 Returns nil in the event that the contents of the line following the
1479 => prefix are empty."
1480 (let ((l (split-string (substring link-line 2))))
1482 (string-trim (elt l 0))
1485 (defun elpher-gemini-get-link-display-string (link-line)
1486 "Extract the display string portion of LINK-LINE, a gemini map file link line.
1487 Return nil if this portion is not provided."
1488 (let* ((rest (string-trim (elt (split-string link-line "=>") 1)))
1489 (idx (string-match "[ \t]" rest)))
1491 (elpher-color-filter-apply (string-trim (substring rest (+ idx 1)))))))
1493 (defun elpher-collapse-dot-sequences (filename)
1494 "Collapse dot sequences in the (absolute) FILENAME.
1495 For instance, the filename \"/a/b/../c/./d\" will reduce to \"/a/c/d\""
1496 (let* ((path (split-string filename "/" t))
1497 (is-directory (string-match-p (rx (: (or "." ".." "/") line-end)) filename))
1498 (path-reversed-normalized
1499 (seq-reduce (lambda (a b)
1500 (cond ((equal b "..") (cdr a))
1504 (path-normalized (reverse path-reversed-normalized)))
1506 (concat "/" (string-join path-normalized "/") (and is-directory "/"))
1509 (defun elpher-address-from-gemini-url (url)
1510 "Extract address from URL with defaults as per gemini map files.
1511 While there's obviously some redundancy here between this function and
1512 `elpher-address-from-url', gemini map file URLs require enough special
1513 treatment that a separate function is warranted."
1514 (let ((address (url-generic-parse-url url))
1515 (current-address (elpher-page-address elpher-current-page)))
1516 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
1517 (if (url-host address) ;if there is an explicit host, filenames are absolute
1518 (if (string-empty-p (url-filename address))
1519 (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
1520 (setf (url-host address) (url-host current-address))
1521 (setf (url-fullness address) (url-host address)) ; set fullness to t if host is set
1522 (setf (url-portspec address) (url-portspec current-address)) ; (url-port) too slow!
1523 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
1524 (setf (url-filename address)
1525 (concat (file-name-directory (url-filename current-address))
1526 (url-filename address)))))
1527 (when (url-host address)
1528 (setf (url-host address) (puny-encode-domain (url-host address))))
1529 (unless (url-type address)
1530 (setf (url-type address) (url-type current-address)))
1531 (when (equal (url-type address) "gemini")
1532 (setf (url-filename address)
1533 (elpher-collapse-dot-sequences (url-filename address)))))
1534 (elpher-remove-redundant-ports address)))
1536 (defun elpher-gemini-insert-link (link-line)
1537 "Insert link described by LINK-LINE into a text/gemini document."
1538 (let ((url (elpher-gemini-get-link-url link-line)))
1540 (let* ((given-display-string (elpher-gemini-get-link-display-string link-line))
1541 (address (elpher-address-from-gemini-url url))
1542 (type (if address (elpher-address-type address) nil))
1543 (type-map-entry (cdr (assoc type elpher-type-map)))
1544 (fill-prefix (make-string (+ 1 (length elpher-gemini-link-string)) ?\s)))
1545 (when type-map-entry
1546 (insert elpher-gemini-link-string)
1547 (let* ((face (elt type-map-entry 3))
1548 (display-string (or given-display-string
1549 (elpher-address-to-iri address)))
1550 (page (elpher-make-page display-string
1552 (insert-text-button display-string
1555 'action #'elpher-click-link
1557 'help-echo #'elpher--page-button-help))
1560 (defun elpher-gemini-insert-header (header-line)
1561 "Insert header described by HEADER-LINE into a text/gemini document.
1562 The gemini map file line describing the header is given
1564 (when (string-match "^\\(#+\\)[ \t]*" header-line)
1565 (let* ((level (length (match-string 1 header-line)))
1566 (header (substring header-line (match-end 0)))
1568 (1 'elpher-gemini-heading1)
1569 (2 'elpher-gemini-heading2)
1570 (3 'elpher-gemini-heading3)
1572 (fill-column (if (display-graphic-p)
1574 (font-get (font-spec :name (face-font 'default)) :size))
1575 (font-get (font-spec :name (face-font face)) :size)) fill-column)))
1576 (unless (display-graphic-p)
1577 (insert (make-string level ?#) " "))
1578 (insert (propertize header
1584 (defun elpher-gemini-insert-text (text-line)
1585 "Insert a plain non-preformatted TEXT-LINE into a text/gemini document.
1586 This function uses Emacs' auto-fill to wrap text sensibly to a maximum
1587 width defined by `elpher-gemini-max-fill-width'."
1591 (group (or (: "*" (+ (any " \t")))
1592 (: ">" (* (any " \t"))))))))
1594 (let* ((line-prefix (match-string 1 text-line))
1595 (processed-text-line
1597 (cond ((string-prefix-p "*" line-prefix)
1599 (replace-regexp-in-string "\\*"
1600 elpher-gemini-bullet-string
1601 (match-string 0 text-line))
1602 (substring text-line (match-end 0))))
1603 ((string-prefix-p ">" line-prefix)
1604 (propertize text-line 'face 'elpher-gemini-quoted))
1607 (fill-prefix (if line-prefix
1608 (make-string (length (match-string 0 text-line)) ?\s)
1610 (insert (elpher-process-text-for-display processed-text-line))
1613 (defun elpher-gemini-pref-expand-collapse (button)
1614 "Function called when the preformatted text toggle BUTTON is activated."
1615 (let ((id (button-get button 'pref-id)))
1616 (if (invisible-p id)
1617 (remove-from-invisibility-spec id)
1618 (add-to-invisibility-spec id))
1621 (defun elpher-gemini-insert-preformatted-toggler (alt-text)
1622 "Insert a button for toggling the visibility of preformatted text.
1623 If non-nil, ALT-TEXT is displayed alongside the button."
1624 (let* ((url-string (url-recreate-url (elpher-page-address elpher-current-page)))
1625 (pref-id (intern (concat "pref-"
1626 (number-to-string (point))
1629 (insert elpher-gemini-preformatted-toggle-bullet)
1631 (insert (propertize (concat alt-text " ")
1632 'face 'elpher-gemin-preformatted)))
1633 (insert-text-button elpher-gemini-preformatted-toggle-label
1634 'action #'elpher-gemini-pref-expand-collapse
1636 'face 'elpher-gemini-preformatted-toggle)
1637 (add-to-invisibility-spec pref-id)
1641 (defun elpher-gemini-insert-preformatted-line (line &optional pref-id)
1642 "Insert a LINE of preformatted text.
1643 PREF-ID is the value assigned to the \"invisible\" text attribute, which
1644 can be used to toggle the display of the preformatted text."
1645 (insert (propertize (concat (elpher-process-text-for-display line) "\n")
1647 'rear-nonsticky t)))
1649 (defun elpher-render-gemini-map (data _parameters)
1650 "Render DATA as a gemini map file, PARAMETERS is currently unused."
1651 (elpher-with-clean-buffer
1653 (setq-local buffer-invisibility-spec nil)
1654 (let ((preformatted nil)
1655 (adaptive-fill-mode nil)) ;Prevent automatic setting of fill-prefix
1656 (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))
1657 (dolist (line (split-string data "\n"))
1659 ((rx (: "```" (opt (let alt-text (+ any)))))
1663 (if elpher-gemini-hide-preformatted
1664 (elpher-gemini-insert-preformatted-toggler alt-text)
1666 ((guard preformatted)
1667 (elpher-gemini-insert-preformatted-line line preformatted))
1668 ((pred (string-prefix-p "=>"))
1669 (elpher-gemini-insert-link line))
1670 ((pred (string-prefix-p "#"))
1671 (elpher-gemini-insert-header line))
1672 (_ (elpher-gemini-insert-text line))))
1673 (elpher-cache-content
1674 (elpher-page-address elpher-current-page)
1677 (defun elpher-render-gemini-plain-text (data _parameters)
1678 "Render DATA as plain text file. PARAMETERS is currently unused."
1679 (elpher-with-clean-buffer
1680 (insert (elpher-process-text-for-display data))
1681 (elpher-cache-content
1682 (elpher-page-address elpher-current-page)
1685 (defun elpher-build-current-imenu-index ()
1686 "Build imenu index for current elpher buffer."
1688 (goto-char (point-min))
1691 (while (setq match (text-property-search-forward 'gemini-heading t t))
1693 (buffer-substring-no-properties (prop-match-beginning match)
1694 (prop-match-end match))
1695 (prop-match-beginning match))
1697 (reverse headers))))
1699 ;; Spartan page retrieval
1701 (defun elpher-get-spartan-page (renderer)
1702 "Getter which retrieves and renders a Spartan page and renders it using RENDERER."
1703 (let* ((address (elpher-page-address elpher-current-page))
1704 (content (elpher-get-cached-content address)))
1705 (condition-case the-error
1706 (if (and content (funcall renderer nil))
1707 (elpher-with-clean-buffer
1709 (elpher-restore-pos))
1710 (elpher-with-clean-buffer
1711 (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
1712 (setq elpher-gemini-redirect-chain nil)
1713 (elpher-get-spartan-response address renderer))
1715 (elpher-network-error address the-error)))))
1717 (defun elpher-get-spartan-response (address renderer)
1718 "Get response string from spartan server at ADDRESS and render using RENDERER."
1719 (elpher-get-host-response address 300
1720 (concat (elpher-address-host address) " "
1721 (elpher-address-filename address) " "
1722 "0\r\n") ; No uploads for now
1723 (lambda (response-string)
1724 (elpher-process-spartan-response response-string renderer))))
1726 (defun elpher-parse-spartan-response (response)
1727 "Parse the RESPONSE string and return a list of components.
1728 The list is of the form (code meta body). A response of nil implies
1729 that the response was malformed."
1730 (let ((header-end-idx (string-match "\r\n" response)))
1732 (let ((header (string-trim (substring response 0 header-end-idx)))
1733 (body (substring response (+ header-end-idx 2))))
1734 (if (>= (length header) 2)
1735 (let ((code (substring header 0 1))
1736 (meta (string-trim (substring header 1))))
1737 (list code meta body))
1738 (error "Malformed response: No response status found in header %s" header)))
1739 (error "Malformed response: No CRLF-delimited header found in response %s" response))))
1741 (defun elpher-process-spartan-response (response-string renderer)
1742 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
1743 (let ((response-components (elpher-parse-gemini-response response-string)))
1744 (let ((response-code (elt response-components 0))
1745 (response-meta (elt response-components 1))
1746 (response-body (elt response-components 2)))
1747 (pcase (elt response-code 0)
1748 (?2 ; Normal response
1749 (funcall renderer response-body response-meta))
1751 (message "Following redirect to %s" response-meta)
1752 (if (>= (length elpher-gemini-redirect-chain) 5)
1753 (error "More than 5 consecutive redirects followed"))
1754 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
1755 (if (member redirect-address elpher-gemini-redirect-chain)
1756 (error "Redirect loop detected"))
1757 (if (not (eq (elpher-address-type redirect-address) 'gemini))
1758 (error "Server tried to automatically redirect to non-gemini URL: %s"
1760 (elpher-page-set-address elpher-current-page redirect-address)
1761 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
1762 (elpher-get-gemini-response redirect-address renderer)))
1763 (?4 ; Temporary failure
1764 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
1765 response-code response-meta))
1766 (?5 ; Permanent failure
1767 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
1768 response-code response-meta))
1769 (?6 ; Client certificate required
1770 (elpher-with-clean-buffer
1771 (if elpher-client-certificate
1772 (insert "Gemini server does not recognise the provided TLS certificate:\n\n")
1773 (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
1775 (elpher-gemini-insert-text response-meta))
1776 (let ((chosen-certificate (elpher-choose-client-certificate)))
1777 (unless chosen-certificate
1778 (error "Gemini server requires a client certificate and none was provided"))
1779 (setq elpher-client-certificate chosen-certificate))
1780 (elpher-with-clean-buffer)
1781 (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer))
1783 (error "Gemini server response unknown: %s %s"
1784 response-code response-meta))))))
1786 ;; Finger page connection
1788 (defun elpher-get-finger-page (renderer)
1789 "Opens a finger connection to the current page address.
1790 The result is rendered using RENDERER."
1791 (let* ((address (elpher-page-address elpher-current-page))
1792 (content (elpher-get-cached-content address)))
1793 (if (and content (funcall renderer nil))
1794 (elpher-with-clean-buffer
1796 (elpher-restore-pos))
1797 (elpher-with-clean-buffer
1798 (insert "LOADING... (use 'u' to cancel)\n"))
1799 (condition-case the-error
1800 (let* ((kill-buffer-query-functions nil)
1801 (user (let ((filename (elpher-address-filename address)))
1802 (if (> (length filename) 1)
1803 (substring filename 1)
1804 (elpher-address-user address)))))
1805 (elpher-get-host-response address 79
1806 (concat user "\r\n")
1809 (elpher-network-error address the-error))))))
1812 ;; Telnet page connection
1814 (defun elpher-get-telnet-page (renderer)
1815 "Opens a telnet connection to the current page address (RENDERER must be nil)."
1817 (elpher-visit-previous-page)
1818 (error "Command not supported for telnet URLs"))
1819 (let* ((address (elpher-page-address elpher-current-page))
1820 (host (elpher-address-host address))
1821 (port (elpher-address-port address)))
1822 (elpher-visit-previous-page)
1828 ;; Other URL page opening
1830 (defun elpher-get-other-url-page (renderer)
1831 "Getter which attempts to open the URL specified by the current page.
1832 The RENDERER argument to this getter must be nil."
1834 (elpher-visit-previous-page)
1835 (error "Command not supported for general URLs"))
1836 (let* ((address (elpher-page-address elpher-current-page))
1837 (url (elpher-address-to-url address)))
1838 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1839 (message "Opening URL...")
1840 (if elpher-open-urls-with-eww
1847 (defun elpher-get-file-page (renderer)
1848 "Getter which renders a local file using RENDERER.
1849 Assumes UTF-8 encoding for all text files."
1850 (let* ((address (elpher-page-address elpher-current-page))
1851 (filename (elpher-address-filename address)))
1852 (unless (file-exists-p filename)
1853 (elpher-visit-previous-page)
1854 (error "File not found"))
1855 (unless (file-readable-p filename)
1856 (elpher-visit-previous-page)
1857 (error "Could not read from file"))
1858 (let ((body (with-temp-buffer
1859 (let ((coding-system-for-read 'binary)
1860 (coding-system-for-write 'binary))
1861 (insert-file-contents-literally filename)
1862 (encode-coding-string (buffer-string) 'raw-text)))))
1864 (funcall renderer body nil)
1865 (pcase (file-name-extension filename)
1866 ((or "gmi" "gemini")
1867 (elpher-render-gemini-map (decode-coding-string body 'utf-8) nil))
1869 (elpher-render-html (decode-coding-string body 'utf-8)))
1871 (elpher-render-text (decode-coding-string body 'utf-8)))
1872 ((or "jpg" "jpeg" "gif" "png" "bmp" "tif" "tiff")
1873 (elpher-render-image body))
1874 ((or "gopher" "gophermap")
1875 (elpher-render-index (elpher-decode body)))
1877 (elpher-render-download body))))
1878 (elpher-restore-pos))))
1881 ;; Welcome page retrieval
1883 (defun elpher-get-welcome-page (renderer)
1884 "Getter which displays the welcome page (RENDERER must be nil)."
1886 (elpher-visit-previous-page)
1887 (error "Command not supported for welcome page"))
1888 (elpher-with-clean-buffer
1889 (insert " --------------------------------------------\n"
1890 " Elpher Gopher and Gemini Client \n"
1891 " version " elpher-version "\n"
1892 " --------------------------------------------\n"
1894 "Default bindings:\n"
1896 " - TAB/Shift-TAB: next/prev item on current page\n"
1897 " - RET/mouse-1: open item under cursor\n"
1898 " - m: select an item on current page by name (autocompletes)\n"
1899 " - u/mouse-3/U: return to previous page or to the start page\n"
1900 " - g: go to a particular address (gopher, gemini, finger)\n"
1901 " - o/O: open a different address selector or the root menu of the current server\n"
1902 " - d/D: download item under cursor or current page\n"
1903 " - i/I: info on item under cursor or current page\n"
1904 " - c/C: copy URL representation of item under cursor or current page\n"
1905 " - a/A: bookmark the item under cursor or current page\n"
1906 " - B: list all bookmarks\n"
1907 " - s/S: show current history stack or all previously visted pages\n"
1908 " - r: redraw current page (using cached contents if available)\n"
1909 " - R: reload current page (regenerates cache)\n"
1910 " - !: set character coding system for gopher (default is to autodetect)\n"
1911 " - T: toggle TLS gopher mode\n"
1912 " - F: forget/discard current TLS client certificate\n"
1913 " - .: display the raw server response for the current page\n"
1915 "Start your exploration of gopher space and gemini:\n")
1916 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1917 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1918 (elpher-insert-index-record "Project Gemini home page"
1919 (elpher-address-from-url "gemini://gemini.circumlunar.space/"))
1921 "Alternatively, select a search engine and enter some search terms:\n")
1922 (elpher-insert-index-record "Gopher Search Engine (Veronica-2)"
1923 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1924 (elpher-insert-index-record "Gemini Search Engine (geminispace.info)"
1925 (elpher-address-from-url "gemini://geminispace.info/search"))
1927 "Your bookmarks are stored in your ")
1928 (insert-text-button "bookmark list"
1930 'action #'elpher-click-link
1932 'help-echo #'elpher--page-button-help
1934 (elpher-make-page "Elpher Bookmarks"
1935 (elpher-make-about-address 'bookmarks)))
1938 "(Bookmarks from legacy elpher-bookmarks files will be automatically imported.)\n"
1941 "The gopher home of the Elpher project is here:\n")
1942 (elpher-insert-index-record "The Elpher Project Page"
1943 (elpher-make-gopher-address ?1
1947 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1949 "The following info documentation is available:\n"
1951 (insert-text-button "Elpher Manual"
1957 'help-echo help-string)
1959 (insert-text-button "Changes introduced by the latest release"
1963 (info "(elpher)News"))
1965 'help-echo help-string))
1968 (concat "(These documents should be available if you have installed Elpher\n"
1969 " from MELPA or non-GNU ELPA. Otherwise you may have to install the\n"
1970 " manual yourself.)\n")
1972 (elpher-restore-pos)))
1975 ;; History page retrieval
1977 (defun elpher-show-history ()
1978 "Show the current contents of elpher's history stack.
1979 Use \\[elpher-show-visited-pages] to see the entire history.
1980 This is rendered using `elpher-get-history-page' via `elpher-type-map'."
1983 (elpher-make-page "Current History Stack"
1984 (elpher-make-about-address 'history))))
1986 (defun elpher-show-visited-pages ()
1987 "Show the all the pages you've visited using Elpher.
1988 Use \\[elpher-show-history] to see just the current history stack.
1989 This is rendered using `elpher-get-visited-pages-page' via `elpher-type-map'."
1992 (elpher-make-page "Elpher Visted Pages"
1993 (elpher-make-about-address 'visited-pages))))
1995 (defun elpher-get-history-page (renderer)
1996 "Getter which displays the history page (RENDERER must be nil)."
1998 (elpher-visit-previous-page)
1999 (error "Command not supported for history page"))
2000 (elpher-display-history-links elpher-history "Current history stack"))
2002 (defun elpher-get-visited-pages-page (renderer)
2003 "Getter which displays the list of visited pages (RENDERER must be nil)."
2005 (elpher-visit-previous-page)
2006 (error "Command not supported for history page"))
2007 (elpher-display-history-links
2008 (seq-filter (lambda (page)
2009 (not (elpher-address-about-p (elpher-page-address page))))
2010 elpher-visited-pages)
2011 "All visited pages"))
2013 (defun elpher-display-history-links (pages title)
2014 "Show all PAGES in an Elpher buffer with a given TITLE."
2015 (let* ((title-line (concat " ---- " title " ----"))
2016 (footer-line (make-string (length title-line) ?-)))
2017 (elpher-with-clean-buffer
2018 (insert title-line "\n\n")
2020 (dolist (page pages)
2022 (let ((display-string (elpher-page-display-string page))
2023 (address (elpher-page-address page)))
2024 (elpher-insert-index-record display-string address))))
2025 (insert "No history items found.\n"))
2026 (insert "\n " footer-line "\n"
2027 "Select an entry or press 'u' to return to the previous page.")
2028 (elpher-restore-pos))))
2033 ;; This code allows Elpher to use the standard Emacs bookmarks: `C-x r
2034 ;; m' to add a bookmark, `C-x r l' to list bookmarks (which is where
2035 ;; you can anotate bookmarks!), `C-x r b' to jump to a bookmark, and
2036 ;; so on. See the Bookmarks section in the Emacs info manual for more.
2038 (defvar elpher-bookmark-link nil
2039 "Prefer bookmarking a link or the current page.
2040 Bind this variable dynamically, or set it to t.
2041 If you set it to t, the commands \\[bookmark-set-no-overwrite]
2042 and \\[elpher-set-bookmark-no-overwrite] do the same thing.")
2044 (defun elpher-bookmark-make-record ()
2045 "Return a bookmark record.
2046 If `elpher-bookmark-link' is non-nil and point is on a link button,
2047 return a bookmark record for that link. Otherwise, return a bookmark
2048 record for the current elpher page."
2049 (let* ((button (and elpher-bookmark-link (button-at (point))))
2051 (button-get button 'elpher-page)
2052 elpher-current-page)))
2054 (error "Cannot bookmark this link"))
2055 (let* ((address (elpher-page-address page))
2056 (url (elpher-address-to-url address))
2057 (display-string (elpher-page-display-string page))
2058 (pos (if button nil (point))))
2059 (if (elpher-address-about-p address)
2060 (error "Cannot bookmark %s" display-string)
2062 (defaults . (,display-string))
2065 (handler . elpher-bookmark-jump))))))
2068 (defun elpher-bookmark-jump (bookmark)
2069 "Handler used to open a bookmark using elpher.
2070 The argument BOOKMARK is a bookmark record passed to the function.
2071 This handler is responsible for loading the bookmark in some buffer,
2072 then making that buffer the current buffer. It should not switch
2074 (let* ((url (cdr (assq 'location bookmark)))
2075 (cleaned-url (string-trim url))
2076 (page (elpher-page-from-url cleaned-url))
2077 (buffer (get-buffer-create elpher-buffer-name)))
2078 (elpher-with-clean-buffer
2079 (elpher-visit-page page))
2083 (defun elpher-bookmark-link ()
2084 "Bookmark the link at point.
2085 To bookmark the current page, use \\[elpher-bookmark-current]."
2087 (let ((elpher-bookmark-link t))
2088 (bookmark-set-no-overwrite)))
2090 (defun elpher-bookmark-current ()
2091 "Bookmark the current page.
2092 To bookmark the link at point use \\[elpher-bookmark-link]."
2094 (call-interactively #'bookmark-set-no-overwrite))
2096 (defun elpher-bookmark-import (file)
2097 "Import legacy Elpher bookmarks file FILE into Emacs bookmarks."
2098 (interactive (list (if (and (boundp 'elpher-bookmarks-file)
2099 (file-readable-p elpher-bookmarks-file))
2100 elpher-bookmarks-file
2101 (read-file-name "Old Elpher bookmarks: "
2102 user-emacs-directory nil t
2103 "elpher-bookmarks"))))
2104 (dolist (bookmark (with-temp-buffer
2105 (insert-file-contents file)
2106 (read (current-buffer))))
2107 (let* ((display-string (car bookmark))
2108 (url (cadr bookmark))
2109 (record `(,display-string
2111 (handler . elpher-bookmark-jump))))
2112 (bookmark-store display-string (cdr record) t)))
2115 (defun elpher-get-bookmarks-page (renderer)
2116 "Getter which displays the bookmarks (RENDERER must be nil)."
2118 (elpher-visit-previous-page)
2119 (error "Command not supported for bookmarks page"))
2121 (let ((old-bookmarks-file (or (and (boundp 'elpher-bookmarks-file)
2122 elpher-bookmarks-file)
2123 (locate-user-emacs-file "elpher-bookmarks"))))
2124 (when (and (file-readable-p old-bookmarks-file)
2125 (y-or-n-p (concat "Legacy elpher-bookmarks file \""
2127 "\" found. Import now?")))
2128 (elpher-bookmark-import old-bookmarks-file)
2129 (rename-file old-bookmarks-file (concat old-bookmarks-file "-legacy"))))
2131 (if (and elpher-use-emacs-bookmark-menu
2134 (elpher-visit-previous-page)
2135 (call-interactively #'bookmark-bmenu-list))
2136 (elpher-with-clean-buffer
2137 (insert " ---- Elpher Bookmarks ---- \n\n")
2138 (bookmark-maybe-load-default-file)
2139 (dolist (bookmark (bookmark-maybe-sort-alist))
2140 (when (eq #'elpher-bookmark-jump (alist-get 'handler (cdr bookmark)))
2141 (let* ((name (car bookmark))
2142 (url (alist-get 'location (cdr bookmark)))
2143 (address (elpher-address-from-url url)))
2144 (elpher-insert-index-record name address))))
2145 (when (<= (line-number-at-pos) 3)
2146 (insert "No bookmarked pages found.\n"))
2147 (insert "\n --------------------------\n\n"
2148 "Select an entry or press 'u' to return to the previous page.\n\n"
2149 "Bookmarks can be renamed or deleted via the ")
2150 (insert-text-button "Emacs bookmark menu"
2153 (call-interactively #'bookmark-bmenu-list))
2155 'help-echo "RET,mouse-1: open Emacs bookmark menu")
2156 (insert (substitute-command-keys
2157 ",\nwhich can also be opened from anywhere using '\\[bookmark-bmenu-list]'."))
2158 (elpher-restore-pos))))
2160 (defun elpher-show-bookmarks ()
2161 "Interactive function to display the current list of elpher bookmarks."
2164 (elpher-make-page "Elpher Bookmarks"
2165 (elpher-make-about-address 'bookmarks))))
2173 (defun elpher-org-export-link (link description format protocol)
2174 "Export a LINK with DESCRIPTION for the given PROTOCOL and FORMAT.
2176 FORMAT is an Org export backend. DESCRIPTION may be nil. PROTOCOL may be one
2177 of gemini, gopher or finger."
2178 (let* ((url (if (equal protocol "elpher")
2179 (string-remove-prefix "elpher:" link)
2180 (format "%s:%s" protocol link)))
2181 (desc (or description url)))
2183 (`gemini (format "=> %s %s" url desc))
2184 (`html (format "<a href=\"%s\">%s</a>" url desc))
2185 (`latex (format "\\href{%s}{%s}" url desc))
2186 (_ (if (not description)
2188 (format "%s (%s)" desc url))))))
2190 (defun elpher-org-store-link ()
2191 "Store link to an `elpher' page in Org."
2192 (when (eq major-mode 'elpher-mode)
2193 (let* ((url (elpher-info-current))
2194 (desc (car elpher-current-page))
2196 ((string-prefix-p "gemini:" url) "gemini")
2197 ((string-prefix-p "gopher:" url) "gopher")
2198 ((string-prefix-p "finger:" url) "finger")
2200 (when (equal "elpher" protocol)
2201 ;; Weird link. Or special inner link?
2202 (setq url (concat "elpher:" url)))
2203 (org-link-store-props :type protocol :link url :description desc)
2206 (defun elpher-org-follow-link (link protocol)
2207 "Visit a LINK for the given PROTOCOL.
2209 PROTOCOL may be one of gemini, gopher or finger. This method also
2210 supports the old protocol elpher, where the link is self-contained."
2211 (let ((url (if (equal protocol "elpher")
2212 (string-remove-prefix "elpher:" link)
2213 (format "%s:%s" protocol link))))
2216 (defun elpher-org-mode-integration ()
2217 "Set up `elpher' integration for `org-mode'."
2218 (org-link-set-parameters
2220 :store #'elpher-org-store-link
2221 :export (lambda (link description format _plist)
2222 (elpher-org-export-link link description format "elpher"))
2223 :follow (lambda (link _arg) (elpher-org-follow-link link "elpher")))
2224 (org-link-set-parameters
2226 :export (lambda (link description format _plist)
2227 (elpher-org-export-link link description format "gemini"))
2228 :follow (lambda (link _arg) (elpher-org-follow-link link "gemini")))
2229 (org-link-set-parameters
2231 :export (lambda (link description format _plist)
2232 (elpher-org-export-link link description format "gopher"))
2233 :follow (lambda (link _arg) (elpher-org-follow-link link "gopher")))
2234 (org-link-set-parameters
2236 :export (lambda (link description format _plist)
2237 (elpher-org-export-link link description format "finger"))
2238 :follow (lambda (link _arg) (elpher-org-follow-link link "finger"))))
2240 (add-hook 'org-mode-hook #'elpher-org-mode-integration)
2245 (defun elpher-browse-url-elpher (url &rest _args)
2246 "Browse URL using Elpher. This function is used by `browse-url'."
2247 (interactive (browse-url-interactive-arg "Elpher URL: "))
2250 ;; Use elpher to open gopher, finger and gemini links
2251 ;; For recent version of `browse-url' package
2252 (if (boundp 'browse-url-default-handlers)
2254 'browse-url-default-handlers
2255 '("^\\(gopher\\|finger\\|gemini\\)://" . elpher-browse-url-elpher))
2256 ;; Patch `browse-url-browser-function' for older ones. The value of
2257 ;; that variable is `browse-url-default-browser' by default, so
2258 ;; that's the function that gets advised. If the value is an alist,
2259 ;; however, we don't know what to do. Better not interfere?
2260 (when (and (symbolp browse-url-browser-function)
2261 (fboundp browse-url-browser-function))
2262 (advice-add browse-url-browser-function :before-while
2263 (lambda (url &rest _args)
2264 "Handle gemini, gopher, and finger schemes using Elpher."
2265 (let ((scheme (downcase (car (split-string url ":" t)))))
2266 (if (member scheme '("gemini" "gopher" "finger"))
2267 ;; `elpher-go' always returns nil, which will stop the
2268 ;; advice chain here in a before-while
2270 ;; chain must continue, then return t.
2273 ;; Register "gemini://" as a URI scheme so `browse-url' does the right thing
2274 (with-eval-after-load 'thingatpt
2275 (add-to-list 'thing-at-point-uri-schemes "gemini://"))
2279 ;; Make mu4e aware of the gemini world
2280 (setq mu4e~view-beginning-of-url-regexp
2281 "\\(?:https?\\|gopher\\|finger\\|gemini\\)://\\|mailto:")
2285 ;; Let elpher handle gemini, gopher links in eww buffer.
2286 (setq eww-use-browse-url
2287 "\\`mailto:\\|\\(\\`gemini\\|\\`gopher\\|\\`finger\\)://")
2290 ;;; Interactive procedures
2293 (defun elpher-next-link ()
2294 "Move point to the next link on the current page."
2298 (defun elpher-prev-link ()
2299 "Move point to the previous link on the current page."
2301 (backward-button 1))
2303 (defun elpher-follow-current-link ()
2304 "Open the link or url at point."
2309 (defun elpher-go (host-or-url)
2310 "Go to a particular gopher site HOST-OR-URL.
2311 When run interactively HOST-OR-URL is read from the minibuffer."
2313 (read-string (format "Visit URL (default scheme %s): " (elpher-get-default-url-scheme)))))
2314 (let ((trimmed-host-or-url (string-trim host-or-url)))
2315 (unless (string-empty-p trimmed-host-or-url)
2316 (let ((page (elpher-page-from-url trimmed-host-or-url
2317 (elpher-get-default-url-scheme))))
2318 (unless (get-buffer-window elpher-buffer-name t)
2319 (switch-to-buffer elpher-buffer-name))
2320 (elpher-with-clean-buffer
2321 (elpher-visit-page page))
2322 nil)))) ; non-nil value is displayed by eshell
2324 (defun elpher-go-current ()
2325 "Go to a particular URL which is read from the minibuffer.
2326 Unlike `elpher-go', the reader is initialized with the URL of the
2329 (let* ((address (elpher-page-address elpher-current-page))
2330 (url (read-string (format "Visit URL (default scheme %s): " (elpher-get-default-url-scheme))
2331 (elpher-address-to-url address))))
2332 (unless (string-empty-p (string-trim url))
2333 (elpher-visit-page (elpher-page-from-url url)))))
2335 (defun elpher-redraw ()
2336 "Redraw current page."
2338 (elpher-visit-page elpher-current-page))
2340 (defun elpher-reload ()
2341 "Reload current page."
2343 (elpher-reload-current-page))
2345 (defun elpher-toggle-tls ()
2346 "Toggle TLS encryption mode for gopher."
2348 (setq elpher-use-tls (not elpher-use-tls))
2350 (if (gnutls-available-p)
2351 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
2352 (setq elpher-use-tls nil)
2353 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
2354 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
2356 (defun elpher-view-raw ()
2357 "View raw server response for current page."
2359 (if (elpher-address-about-p (elpher-page-address elpher-current-page))
2360 (error "This page was not generated by a server")
2361 (elpher-visit-page elpher-current-page
2362 #'elpher-render-raw)))
2364 (defun elpher-back ()
2365 "Go to previous site."
2367 (elpher-visit-previous-page))
2369 (defun elpher-back-to-start ()
2370 "Go all the way back to the start page."
2372 (setq-local elpher-current-page nil)
2373 (setq-local elpher-history nil)
2374 (elpher-visit-page (elpher-make-start-page)))
2376 (defun elpher-download ()
2377 "Download the link at point."
2379 (let ((button (button-at (point))))
2381 (let ((page (button-get button 'elpher-page)))
2383 (error "Not an elpher page"))
2384 (when (elpher-address-about-p (elpher-page-address page))
2385 (error "Cannot download %s" (elpher-page-display-string page)))
2386 (elpher-visit-page (button-get button 'elpher-page)
2387 #'elpher-render-download))
2388 (error "No link selected"))))
2390 (defun elpher-download-current ()
2391 "Download the current page."
2393 (if (elpher-address-about-p (elpher-page-address elpher-current-page))
2394 (error "Cannot download %s"
2395 (elpher-page-display-string elpher-current-page))
2396 (elpher-visit-page (elpher-make-page
2397 (elpher-page-display-string elpher-current-page)
2398 (elpher-page-address elpher-current-page))
2399 #'elpher-render-download
2402 (defun elpher--build-link-map ()
2403 "Build alist mapping link names to destination pages in current buffer."
2404 (let ((link-map nil)
2405 (b (next-button (point-min) t)))
2407 (push (cons (button-label b) b) link-map)
2408 (setq b (next-button (button-start b))))
2411 (defun elpher-jump ()
2412 "Select a directory entry by name. Similar to the info browser (m)enu command."
2414 (let* ((link-map (elpher--build-link-map)))
2416 (let ((key (let ((completion-ignore-case t))
2417 (completing-read "Directory item/link: "
2419 (if (and key (> (length key) 0))
2420 (let ((b (cdr (assoc key link-map))))
2421 (goto-char (button-start b))
2422 (button-activate b)))))))
2424 (defun elpher-root-dir ()
2425 "Visit root of current server."
2427 (let ((address (elpher-page-address elpher-current-page)))
2428 (if (not (elpher-address-about-p address))
2429 (if (or (member (url-filename address) '("/" ""))
2430 (and (elpher-address-gopher-p address)
2431 (= (length (elpher-gopher-address-selector address)) 0)))
2432 (error "Already at root directory of current server")
2433 (let ((address-copy (elpher-address-from-url
2434 (elpher-address-to-url address))))
2435 (setf (url-filename address-copy) "")
2436 (elpher-go (elpher-address-to-url address-copy))))
2437 (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
2439 (defun elpher-info-page (page)
2440 "Display URL of PAGE in minibuffer."
2441 (let* ((address (elpher-page-address page))
2442 (url (elpher-address-to-url address))
2443 (iri (elpher-address-to-iri address)))
2446 (message "%s (Raw: %s)" iri url))))
2448 (defun elpher-info-link ()
2449 "Display information on page corresponding to link at point."
2451 (let ((button (button-at (point))))
2453 (error "No item selected"))
2454 (let ((page (button-get button 'elpher-page)))
2456 (error "Not an elpher page"))
2457 (elpher-info-page page))))
2459 (defun elpher-info-current ()
2460 "Display information on current page."
2462 (elpher-info-page elpher-current-page))
2464 (defun elpher-copy-page-url (page)
2465 "Copy URL representation of address of PAGE to `kill-ring'."
2466 (let* ((address (elpher-page-address page))
2467 (url (elpher-address-to-url address)))
2468 (message "Copied \"%s\" to kill-ring/clipboard." url)
2471 (defun elpher-copy-link-url ()
2472 "Copy URL of item at point to `kill-ring'."
2474 (let ((button (button-at (point))))
2476 (error "No item selected"))
2477 (let ((page (button-get button 'elpher-page)))
2479 (error "Not an elpher page"))
2480 (elpher-copy-page-url page))))
2482 (defun elpher-copy-current-url ()
2483 "Copy URL of current page to `kill-ring'."
2485 (elpher-copy-page-url elpher-current-page))
2487 (defun elpher-set-gopher-coding-system ()
2488 "Specify an explicit character coding system for gopher selectors."
2490 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
2491 (setq elpher-user-coding-system system)
2493 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
2494 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
2500 (defvar elpher-mode-map
2501 (let ((map (make-sparse-keymap)))
2502 (define-key map (kbd "TAB") 'elpher-next-link)
2503 (define-key map (kbd "<backtab>") 'elpher-prev-link)
2504 (define-key map (kbd "C-M-i") 'elpher-prev-link)
2505 (define-key map (kbd "u") 'elpher-back)
2506 (define-key map (kbd "-") 'elpher-back)
2507 (define-key map (kbd "^") 'elpher-back)
2508 (define-key map [mouse-3] 'elpher-back)
2509 (define-key map (kbd "U") 'elpher-back-to-start)
2510 (define-key map (kbd "g") 'elpher-go)
2511 (define-key map (kbd "o") 'elpher-go-current)
2512 (define-key map (kbd "O") 'elpher-root-dir)
2513 (define-key map (kbd "s") 'elpher-show-history)
2514 (define-key map (kbd "S") 'elpher-show-visited-pages)
2515 (define-key map (kbd "r") 'elpher-redraw)
2516 (define-key map (kbd "R") 'elpher-reload)
2517 (define-key map (kbd "T") 'elpher-toggle-tls)
2518 (define-key map (kbd ".") 'elpher-view-raw)
2519 (define-key map (kbd "d") 'elpher-download)
2520 (define-key map (kbd "D") 'elpher-download-current)
2521 (define-key map (kbd "m") 'elpher-jump)
2522 (define-key map (kbd "i") 'elpher-info-link)
2523 (define-key map (kbd "I") 'elpher-info-current)
2524 (define-key map (kbd "c") 'elpher-copy-link-url)
2525 (define-key map (kbd "C") 'elpher-copy-current-url)
2526 (define-key map (kbd "a") 'elpher-bookmark-link)
2527 (define-key map (kbd "A") 'elpher-bookmark-current)
2528 (define-key map (kbd "B") 'elpher-show-bookmarks)
2529 (define-key map (kbd "!") 'elpher-set-gopher-coding-system)
2530 (define-key map (kbd "F") 'elpher-forget-current-certificate)
2531 (when (fboundp 'evil-define-key*)
2534 (kbd "TAB") 'elpher-next-link
2535 (kbd "C-") 'elpher-follow-current-link
2536 (kbd "C-t") 'elpher-back
2537 (kbd "u") 'elpher-back
2538 (kbd "-") 'elpher-back
2539 (kbd "^") 'elpher-back
2540 [mouse-3] 'elpher-back
2541 (kbd "U") 'elpher-back-to-start
2542 (kbd "g") 'elpher-go
2543 (kbd "o") 'elpher-go-current
2544 (kbd "O") 'elpher-root-dir
2545 (kbd "s") 'elpher-show-history
2546 (kbd "S") 'elpher-show-visited-pages
2547 (kbd "r") 'elpher-redraw
2548 (kbd "R") 'elpher-reload
2549 (kbd "T") 'elpher-toggle-tls
2550 (kbd ".") 'elpher-view-raw
2551 (kbd "d") 'elpher-download
2552 (kbd "D") 'elpher-download-current
2553 (kbd "m") 'elpher-jump
2554 (kbd "i") 'elpher-info-link
2555 (kbd "I") 'elpher-info-current
2556 (kbd "c") 'elpher-copy-link-url
2557 (kbd "C") 'elpher-copy-current-url
2558 (kbd "a") 'elpher-bookmark-link
2559 (kbd "A") 'elpher-bookmark-current
2560 (kbd "B") 'elpher-show-bookmarks
2561 (kbd "!") 'elpher-set-gopher-coding-system
2562 (kbd "F") 'elpher-forget-current-certificate))
2564 "Keymap for gopher client.")
2566 (define-derived-mode elpher-mode special-mode "elpher"
2567 "Major mode for elpher, an elisp gopher client.
2569 This mode is automatically enabled by the interactive
2570 functions which initialize the client, namely
2571 `elpher', and `elpher-go'."
2572 (setq-local elpher-current-page nil)
2573 (setq-local elpher-history nil)
2574 (setq-local elpher-buffer-name (buffer-name))
2575 (setq-local bookmark-make-record-function #'elpher-bookmark-make-record)
2576 (setq-local imenu-create-index-function #'elpher-build-current-imenu-index))
2578 (when (fboundp 'evil-set-initial-state)
2579 (evil-set-initial-state 'elpher-mode 'motion))
2582 ;;; Main start procedure
2586 (defun elpher (&optional arg)
2587 "Start elpher with default landing page.
2588 The buffer used for Elpher sessions is determined by the value of
2589 ‘elpher-buffer-name’. If there is already an Elpher session active in
2590 that buffer, Emacs will simply switch to it. Otherwise, a new session
2591 will begin. A numeric prefix ARG (as in ‘\\[universal-argument] 42
2592 \\[execute-extended-command] elpher RET’) switches to the session with
2593 that number, creating it if necessary. A non numeric prefix ARG means
2594 to create a new session. Returns the buffer selected (or created)."
2596 (let* ((name (default-value 'elpher-buffer-name))
2597 (buf (cond ((numberp arg)
2598 (get-buffer-create (format "%s<%d>" name arg)))
2600 (generate-new-buffer name))
2602 (get-buffer-create name)))))
2603 (pop-to-buffer-same-window buf)
2604 (unless (buffer-modified-p)
2606 (elpher-visit-page (elpher-make-start-page))
2607 "Started Elpher."))); Otherwise (elpher) evaluates to start page string.
2609 ;;; elpher.el ends here