1 ;;; elpher.el --- A friendly gopher and gemini client -*- lexical-binding: t -*-
3 ;; Copyright (C) 2021 Jens Östlund <jostlund@gmail.com>
4 ;; Copyright (C) 2021 F. Jason Park <jp@neverwas.me>
5 ;; Copyright (C) 2021 Christopher Brannon <chris@the-brannons.com>
6 ;; Copyright (C) 2021 Omar Polo <op@omarpolo.com>
7 ;; Copyright (C) 2021 Noodles! <nnoodle@chiru.no>
8 ;; Copyright (C) 2021 Abhiseck Paira <abhiseckpaira@disroot.org>
9 ;; Copyright (C) 2021-2022 Daniel Semyonov <daniel@dsemy.com>
10 ;; Copyright (C) 2020-2021 Alex Schroeder <alex@gnu.org>
11 ;; Copyright (C) 2020 Zhiwei Chen <chenzhiwei03@kuaishou.com>
12 ;; Copyright (C) 2020 condy0919 <condy0919@gmail.com>
13 ;; Copyright (C) 2020 Alexis <flexibeast@gmail.com>
14 ;; Copyright (C) 2020 Étienne Deparis <etienne@depar.is>
15 ;; Copyright (C) 2020 Simon Nicolussi <sinic@sinic.name>
16 ;; Copyright (C) 2020 Michel Alexandre Salim <michel@michel-slm.name>
17 ;; Copyright (C) 2020 Koushk Roy <kroy@twilio.com>
18 ;; Copyright (C) 2020 Vee <vee@vnsf.xyz>
19 ;; Copyright (C) 2020 Simon South <simon@simonsouth.net>
20 ;; Copyright (C) 2019-2022 Tim Vaughan <plugd@thelambdalab.xyz>
22 ;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
23 ;; Created: 11 April 2019
25 ;; Keywords: comm gopher
26 ;; Homepage: https://thelambdalab.xyz/elpher
27 ;; Package-Requires: ((emacs "27.1"))
29 ;; This file is not part of GNU Emacs.
31 ;; This program is free software: you can redistribute it and/or modify
32 ;; it under the terms of the GNU General Public License as published by
33 ;; the Free Software Foundation, either version 3 of the License, or
34 ;; (at your option) any later version.
36 ;; This program is distributed in the hope that it will be useful,
37 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
38 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
39 ;; GNU General Public License for more details.
41 ;; You should have received a copy of the GNU General Public License
42 ;; along with this file. If not, see <http://www.gnu.org/licenses/>.
46 ;; Elpher aims to provide a practical and friendly gopher and gemini
47 ;; client for GNU Emacs. It supports:
49 ;; - intuitive keyboard and mouse-driven browsing,
50 ;; - out-of-the-box compatibility with evil-mode,
51 ;; - clickable web and gopher links *in plain text*,
52 ;; - caching of visited sites,
53 ;; - pleasant and configurable colouring of Gopher directories,
54 ;; - direct visualisation of image files,
55 ;; - gopher connections using TLS encryption,
56 ;; - the fledgling Gemini protocol,
57 ;; - the greybeard Finger protocol.
59 ;; To launch Elpher, simply use 'M-x elpher'. This will open a start
60 ;; page containing information on key bindings and suggested starting
61 ;; points for your gopher exploration.
63 ;; Full instructions can be found in the Elpher info manual.
65 ;; Elpher is under active development. Any suggestions for
66 ;; improvements are welcome, and can be made on the official project
67 ;; page, gopher://thelambdalab.xyz/1/projects/elpher, or via the
68 ;; project mailing list at https://lists.sr.ht/~michel-slm/elpher.
89 (defconst elpher-version "3.2.2"
90 "Current version of elpher.")
92 (defconst elpher-margin-width 6
93 "Width of left-hand margin used when rendering indicies.")
95 (defconst elpher-type-map
96 '(((gopher ?0) elpher-get-gopher-page elpher-render-text "txt" elpher-text)
97 ((gopher ?1) elpher-get-gopher-page elpher-render-index "/" elpher-index)
98 ((gopher ?4) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
99 ((gopher ?5) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
100 ((gopher ?7) elpher-get-gopher-query-page elpher-render-index "?" elpher-search)
101 ((gopher ?9) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
102 ((gopher ?g) elpher-get-gopher-page elpher-render-image "img" elpher-image)
103 ((gopher ?p) elpher-get-gopher-page elpher-render-image "img" elpher-image)
104 ((gopher ?I) elpher-get-gopher-page elpher-render-image "img" elpher-image)
105 ((gopher ?d) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
106 ((gopher ?P) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
107 ((gopher ?s) elpher-get-gopher-page elpher-render-download "snd" elpher-binary)
108 ((gopher ?h) elpher-get-gopher-page elpher-render-html "htm" elpher-html)
109 (gemini elpher-get-gemini-page elpher-render-gemini "gem" elpher-gemini)
110 (finger elpher-get-finger-page elpher-render-text "txt" elpher-text)
111 (telnet elpher-get-telnet-page nil "tel" elpher-telnet)
112 (other-url elpher-get-other-url-page nil "url" elpher-other-url)
113 (file elpher-get-file-page nil "~" elpher-gemini)
114 ((about welcome) elpher-get-welcome-page nil "E" elpher-index)
115 ((about bookmarks) elpher-get-bookmarks-page nil "E" elpher-index)
116 ((about history) elpher-get-history-page nil "E" elpher-index)
117 ((about visited-pages) elpher-get-visited-pages-page nil "E" elpher-index))
118 "Association list from types to getters, renderers, margin codes and index faces.")
121 ;;; Declarations to avoid compiler warnings.
125 (declare-function ansi-color-filter-apply "ansi-color")
126 (declare-function ansi-color-apply "ansi-color")
127 (declare-function bookmark-store "bookmark")
128 (declare-function org-link-store-props "ol")
129 (declare-function org-link-set-parameters "ol")
130 (defvar ansi-color-context)
131 (defvar bookmark-make-record-function)
132 (defvar mu4e~view-beginning-of-url-regexp)
133 (defvar eww-use-browse-url)
134 (defvar thing-at-point-uri-schemes))
137 ;;; Customization group
141 "A gopher and gemini client."
142 :group 'applications)
144 ;; General appearance and customizations
146 (defcustom elpher-open-urls-with-eww nil
147 "If non-nil, open URL selectors using eww.
148 Otherwise, use the system browser via the `browse-url' function."
151 (defcustom elpher-use-header t
152 "If non-nil, display current page information in buffer header."
155 (defcustom elpher-auto-disengage-TLS nil
156 "If non-nil, automatically disengage TLS following an unsuccessful connection.
157 While enabling this may seem convenient, it is also potentially
158 dangerous as it allows switching from an encrypted channel back to
159 plain text without user input."
162 (defcustom elpher-connection-timeout 5
163 "Specifies the number of seconds to wait for a network connection to time out."
166 (defcustom elpher-filter-ansi-from-text nil
167 "If non-nil, filter ANSI escape sequences from text.
168 The default behaviour is to use the ansi-color package to interpret these
172 (defcustom elpher-certificate-directory
173 (file-name-as-directory (locate-user-emacs-file "elpher-certificates"))
174 "Specify the name of the directory where client certificates will be stored.
175 These certificates may be used for establishing authenticated TLS connections."
178 (defcustom elpher-openssl-command "openssl"
179 "The command used to launch openssl when generating TLS client certificates."
182 (defcustom elpher-default-url-type "gopher"
183 "Default URL type (i.e. scheme) to assume if not explicitly given."
184 :type '(choice (const "gopher")
187 (defcustom elpher-gemini-TLS-cert-checks nil
188 "If non-nil, verify gemini server TLS certs using the default security level.
189 Otherwise, certificate verification is disabled.
191 This defaults to off because it is standard practice for Gemini servers
192 to use self-signed certificates, meaning that most servers provide what
193 EMACS considers to be an invalid certificate."
196 (defcustom elpher-gemini-max-fill-width 80
197 "Specify the maximum default width (in columns) of text/gemini documents.
198 The actual width used is the minimum of this value and the window width at
199 the time when the text is rendered."
202 (defcustom elpher-gemini-link-string "→ "
203 "Specify the string used to indicate links when rendering gemini maps.
207 (defcustom elpher-gemini-bullet-string "•"
208 "Specify the string used for bullets when rendering gemini maps."
211 (defcustom elpher-ipv4-always nil
212 "If non-nil, elpher will always use IPv4 to establish network connections.
213 This can be useful when browsing from a computer that supports IPv6, because
214 some servers which do not support IPv6 can take a long time to time-out."
217 (defcustom elpher-socks-always nil
218 "If non-nil, elpher will establish network connections over a SOCKS proxy.
219 Otherwise, the SOCKS proxy is only used for connections to onion services."
222 (defcustom elpher-use-emacs-bookmark-menu nil
223 "If non-nil, elpher will only use the native Emacs bookmark menu.
224 Otherwise, \\[elpher-show-bookmarks] will visit a special elpher bookmark
225 page within which all of the standard elpher keybindings are active."
228 (defcustom elpher-start-page-url "about:welcome"
229 "Specify the page displayed initially by elpher.
230 The default welcome screen is \"about:welcome\", while the bookmarks list
231 is \"about:bookmarks\". You can also specify local files via \"file:\".
233 Beware that using \"about:bookmarks\" as a start page in combination with
234 the `elpher-use-bookmark-menu' variable set to non-nil will prevent the
235 Emacs bookmark menu being accessible via \\[elpher-show-bookmarks] from
239 ;; Face customizations
241 (defgroup elpher-faces nil
242 "Elpher face customizations."
245 (defface elpher-index
246 '((t :inherit font-lock-keyword-face))
247 "Face used for directory type directory records.")
251 "Face used for text type directory records.")
254 '((t :inherit default))
255 "Face used for info type directory records.")
257 (defface elpher-image
258 '((t :inherit font-lock-string-face))
259 "Face used for image type directory records.")
261 (defface elpher-search
262 '((t :inherit warning))
263 "Face used for search type directory records.")
266 '((t :inherit font-lock-comment-face))
267 "Face used for html type directory records.")
269 (defface elpher-gemini
270 '((t :inherit font-lock-constant-face))
271 "Face used for Gemini type directory records.")
273 (defface elpher-other-url
274 '((t :inherit font-lock-comment-face))
275 "Face used for other URL type links records.")
277 (defface elpher-telnet
278 '((t :inherit font-lock-function-name-face))
279 "Face used for telnet type directory records.")
281 (defface elpher-binary
282 '((t :inherit font-lock-doc-face))
283 "Face used for binary type directory records.")
285 (defface elpher-unknown
286 '((t :inherit error))
287 "Face used for directory records with unknown/unsupported types.")
289 (defface elpher-margin-key
291 "Face used for directory margin key.")
293 (defface elpher-margin-brackets
294 '((t :inherit shadow))
295 "Face used for brackets around directory margin key.")
297 (defface elpher-gemini-heading1
298 '((t :inherit bold :height 1.8))
299 "Face used for gemini heading level 1.")
301 (defface elpher-gemini-heading2
302 '((t :inherit bold :height 1.5))
303 "Face used for gemini heading level 2.")
305 (defface elpher-gemini-heading3
306 '((t :inherit bold :height 1.2))
307 "Face used for gemini heading level 3.")
309 (defface elpher-gemini-preformatted
310 '((t :inherit fixed-pitch))
311 "Face used for pre-formatted gemini text blocks.")
313 (defface elpher-gemini-quoted
314 '((t :inherit font-lock-doc-face))
315 "Face used for gemini quoted texts.")
322 ;; An elpher "address" object is either a url object or a symbol.
323 ;; Addresses with the "about" type, corresponding to pages generated
324 ;; dynamically for and by elpher. All others represent pages which
325 ;; rely on content retrieved over the network.
327 (defun elpher-address-from-url (url-string &optional default-scheme)
328 "Create a ADDRESS object corresponding to the given URL-STRING.
329 If DEFAULT-SCHEME is non-nil, this sets the scheme of the URL when one
330 is not explicitly given."
331 (let ((data (match-data))) ; Prevent parsing clobbering match data
333 (let ((url (url-generic-parse-url url-string)))
334 (unless (and (not (url-fullness url)) (url-type url))
335 (unless (url-type url)
336 (setf (url-type url) default-scheme))
337 (unless (url-host url)
338 (let ((p (split-string (url-filename url) "/" nil nil)))
339 (setf (url-host url) (car p))
340 (setf (url-filename url)
342 (concat "/" (mapconcat #'identity (cdr p) "/"))
344 (when (not (string-empty-p (url-host url)))
345 (setf (url-fullness url) t)
346 (setf (url-host url) (puny-encode-domain (url-host url))))
347 (when (or (equal "gopher" (url-type url))
348 (equal "gophers" (url-type url)))
350 (when (or (equal (url-filename url) "")
351 (equal (url-filename url) "/"))
352 (setf (url-filename url) "/1")))
353 (when (equal "gemini" (url-type url))
355 (if (equal (url-filename url) "")
356 (setf (url-filename url) "/"))))
357 (elpher-remove-redundant-ports url))
358 (set-match-data data))))
360 (defun elpher-remove-redundant-ports (address)
361 "Remove redundant port specifiers from ADDRESS.
362 Here 'redundant' means that the specified port matches the default
363 for that protocol, eg 70 for gopher."
364 (if (and (not (elpher-address-about-p address))
365 (eq (url-portspec address) ; (url-port) is too slow!
366 (pcase (url-type address)
368 ((or "gopher" "gophers") 70)
371 (setf (url-portspec address) nil))
374 (defun elpher-make-gopher-address (type selector host port &optional tls)
375 "Create an ADDRESS object using gopher directory record attributes.
376 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
377 If the optional attribute TLS is non-nil, the address will be marked as
378 requiring gopher-over-TLS."
380 ((equal type ?i) nil)
381 ((and (equal type ?h)
382 (string-prefix-p "URL:" selector))
383 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
385 (elpher-address-from-url
388 ":" (number-to-string port))))
390 (elpher-address-from-url
391 (concat "gopher" (if tls "s" "")
393 ":" (number-to-string port)
397 (defun elpher-make-about-address (type)
398 "Create an ADDRESS object corresponding to the given about address TYPE."
399 (elpher-address-from-url (concat "about:" (symbol-name type))))
401 (defun elpher-address-to-url (address)
402 "Get string representation of ADDRESS."
403 (url-encode-url (url-recreate-url address)))
405 (defun elpher-address-type (address)
406 "Retrieve type of ADDRESS object.
407 This is used to determine how to retrieve and render the document the
408 address refers to, via the table `elpher-type-map'."
409 (pcase (url-type address)
411 (list 'about (intern (url-filename address))))
412 ((or "gopher" "gophers")
414 (if (member (url-filename address) '("" "/"))
416 (string-to-char (substring (url-filename address) 1)))))
423 (defun elpher-address-about-p (address)
424 "Return non-nil if ADDRESS is an about address."
425 (pcase (elpher-address-type address) (`(about ,_) t)))
427 (defun elpher-address-gopher-p (address)
428 "Return non-nill if ADDRESS object is a gopher address."
429 (pcase (elpher-address-type address) (`(gopher ,_) t)))
431 (defun elpher-address-protocol (address)
432 "Retrieve the transport protocol for ADDRESS."
435 (defun elpher-address-filename (address)
436 "Retrieve the filename component of ADDRESS.
437 For gopher addresses this is a combination of the selector type and selector."
438 (url-unhex-string (url-filename address)))
440 (defun elpher-address-host (address)
441 "Retrieve host from ADDRESS object."
444 (defun elpher-address-user (address)
445 "Retrieve user from ADDRESS object."
448 (defun elpher-address-port (address)
449 "Retrieve port from ADDRESS object.
450 If no address is defined, returns 0. (This is for compatibility with the URL library.)"
453 (defun elpher-gopher-address-selector (address)
454 "Retrieve gopher selector from ADDRESS object."
455 (if (member (url-filename address) '("" "/"))
457 (url-unhex-string (substring (url-filename address) 2))))
462 (defvar elpher-content-cache (make-hash-table :test 'equal))
463 (defvar elpher-pos-cache (make-hash-table :test 'equal))
465 (defun elpher-get-cached-content (address)
466 "Retrieve the cached content for ADDRESS, or nil if none exists."
467 (gethash address elpher-content-cache))
469 (defun elpher-cache-content (address content)
470 "Set the content cache for ADDRESS to CONTENT."
471 (puthash address content elpher-content-cache))
473 (defun elpher-get-cached-pos (address)
474 "Retrieve the cached cursor position for ADDRESS, or nil if none exists."
475 (gethash address elpher-pos-cache))
477 (defun elpher-cache-pos (address pos)
478 "Set the cursor position cache for ADDRESS to POS."
479 (puthash address pos elpher-pos-cache))
484 (defun elpher-make-page (display-string address)
485 "Create a page with DISPLAY-STRING and ADDRESS."
486 (list display-string address))
488 (defun elpher-make-start-page ()
489 "Create the start page."
490 (elpher-make-page "Start Page"
491 (elpher-address-from-url elpher-start-page-url)))
493 (defun elpher-page-display-string (page)
494 "Retrieve the display string corresponding to PAGE."
497 (defun elpher-page-address (page)
498 "Retrieve the address corresponding to PAGE."
501 (defun elpher-page-set-address (page new-address)
502 "Set the address corresponding to PAGE to NEW-ADDRESS."
503 (setcar (cdr page) new-address))
505 (defun elpher-page-from-url (url &optional default-scheme)
506 "Create a page with address and display string defined by URL.
507 The URL is unhexed prior to its use as a display string to improve
510 If DEFAULT-SCHEME is non-nil, this scheme is applied to the URL
511 in the instance that URL itself doesn't specify one."
512 (let ((address (elpher-address-from-url url default-scheme)))
513 (elpher-make-page (elpher-address-to-iri address) address)))
515 (defun elpher-address-to-iri (address)
516 "Return an IRI for ADDRESS.
517 Decode percent-escapes and handle punycode in the domain name.
518 Drop the password, if any."
519 (let ((data (match-data)) ; Prevent parsing clobbering match data
520 (host (url-host address))
521 (pass (url-password address)))
523 (let* ((host (url-host address))
524 (pass (url-password address)))
526 (setf (url-host address) (puny-decode-domain host)))
527 (when pass ; RFC 3986 says we should not render
528 (setf (url-password address) nil)) ; the password as clear text
529 (elpher-decode (url-unhex-string (url-recreate-url address))))
530 (setf (url-host address) host)
531 (setf (url-password address) pass)
532 (set-match-data data))))
534 (defvar elpher-current-page nil
535 "The current page for this Elpher buffer.")
537 (defvar elpher-history nil
538 "The local history stack for this Elpher buffer.
539 This variable is used by `elpher-back' and
540 `elpher-show-history'.")
542 (defvar elpher-visited-pages nil
543 "The global history for all Elpher buffers.
544 This variable is used by `elpher-show-visited-pages'.")
546 (defun elpher-visit-page (page &optional renderer no-history)
547 "Visit PAGE using its own renderer or RENDERER, if non-nil.
548 Additionally, push PAGE onto the history stack and the list of
549 previously-visited pages,unless NO-HISTORY is non-nil."
551 (elpher-process-cleanup)
553 (unless (or (not elpher-current-page)
554 (equal (elpher-page-address elpher-current-page)
555 (elpher-page-address page)))
556 (push elpher-current-page elpher-history)
557 (unless (or (elpher-address-about-p (elpher-page-address page))
558 (and elpher-visited-pages
559 (equal page (car elpher-visited-pages))))
560 (push page elpher-visited-pages))))
561 (setq-local elpher-current-page page)
562 (let* ((address (elpher-page-address page))
563 (type (elpher-address-type address))
564 (type-record (cdr (assoc type elpher-type-map))))
566 (funcall (car type-record)
570 (elpher-visit-previous-page)
572 (`(gopher ,type-char)
573 (error "Unsupported gopher selector type '%c' for '%s'"
574 type-char (elpher-address-to-url address)))
576 (error "Unsupported address type '%S' for '%s'"
577 other (elpher-address-to-url address)))))))
579 (defun elpher-visit-previous-page ()
580 "Visit the previous page in the history."
582 (elpher-visit-page (pop elpher-history) nil t)
583 (error "No previous page")))
585 (defun elpher-reload-current-page ()
586 "Reload the current page, discarding any existing cached content."
587 (elpher-cache-content (elpher-page-address elpher-current-page) nil)
588 (elpher-visit-page elpher-current-page))
590 (defun elpher-save-pos ()
591 "Save the current position of point to the current page."
592 (when elpher-current-page
593 (elpher-cache-pos (elpher-page-address elpher-current-page) (point))))
595 (defun elpher-restore-pos ()
596 "Restore the position of point to that cached in the current page."
597 (let ((pos (elpher-get-cached-pos (elpher-page-address elpher-current-page))))
600 (goto-char (point-min)))))
602 (defun elpher-get-default-url-scheme ()
603 "Suggest a default URL scheme to use for visiting addresses based on the current page."
604 (if elpher-current-page
605 (let* ((address (elpher-page-address elpher-current-page))
606 (current-type (elpher-address-type address)))
608 ((or (and 'file (guard (not elpher-history)))
610 elpher-default-url-type)
612 elpher-default-url-type)
614 (url-type address))))
615 elpher-default-url-type))
618 ;;; Buffer preparation
621 (defvar elpher-buffer-name "*elpher*"
622 "The default name of the Elpher buffer.")
624 (defun elpher-update-header ()
625 "If `elpher-use-header' is true, display current page info in window header."
626 (if (and elpher-use-header elpher-current-page)
627 (let* ((display-string (elpher-page-display-string elpher-current-page))
628 (sanitized-display-string (replace-regexp-in-string "%" "%%" display-string))
629 (address (elpher-page-address elpher-current-page))
630 (tls-string (if (and (not (elpher-address-about-p address))
631 (member (elpher-address-protocol address)
632 '("gophers" "gemini")))
635 (header (concat sanitized-display-string
636 (propertize tls-string 'face 'bold))))
637 (setq header-line-format header))))
639 (defmacro elpher-with-clean-buffer (&rest args)
640 "Evaluate ARGS with a clean *elpher* buffer as current."
641 (declare (debug (body))) ;; Allow edebug to step through body
642 `(with-current-buffer elpher-buffer-name
643 (unless (eq major-mode 'elpher-mode)
644 ;; avoid resetting buffer-local variables
646 (let ((inhibit-read-only t)
647 (ansi-color-context nil)) ;; clean ansi interpreter state
648 (setq-local network-security-level
649 (default-value 'network-security-level))
651 (elpher-update-header)
654 (defun elpher-buffer-message (string &optional line)
655 "Replace first line in elpher buffer with STRING.
656 If LINE is non-nil, replace that line instead."
657 (with-current-buffer elpher-buffer-name
658 (let ((inhibit-read-only t))
659 (goto-char (point-min))
662 (let ((data (match-data)))
665 (re-search-forward "^.*$")
666 (replace-match string))
667 (set-match-data data))))))
673 (defvar elpher-user-coding-system nil
674 "User-specified coding system to use for decoding text responses.")
676 (defun elpher-decode (string)
677 "Decode STRING using autodetected or user-specified coding system."
678 (decode-coding-string string
679 (if elpher-user-coding-system
680 elpher-user-coding-system
681 (detect-coding-string string t))))
683 (defun elpher-preprocess-text-response (string)
684 "Preprocess text selector response contained in STRING.
685 This involes decoding the character representation, and clearing
686 away CRs and any terminating period."
687 (elpher-decode (replace-regexp-in-string "\n\\.\n$" "\n"
688 (replace-regexp-in-string "\r" "" string))))
692 (defconst elpher-url-regex
693 "\\([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_~?/@|#-]\\)?\\)?"
694 "Regexp used to locate and buttonify URLs in text files loaded by elpher.")
696 (defun elpher-buttonify-urls (string)
697 "Turn substrings which look like urls in STRING into clickable buttons."
700 (goto-char (point-min))
701 (while (re-search-forward elpher-url-regex nil t)
702 (let ((page (elpher-page-from-url (substring-no-properties (match-string 0)))))
703 (make-text-button (match-beginning 0)
706 'action #'elpher-click-link
708 'help-echo #'elpher--page-button-help
712 ;;; ANSI colors or XTerm colors (application and filtering)
714 (or (require 'xterm-color nil t)
715 (require 'ansi-color))
717 (defalias 'elpher-color-filter-apply
718 (if (fboundp 'xterm-color-filter)
720 (let ((_xterm-color-render nil))
721 (xterm-color-filter s)))
722 #'ansi-color-filter-apply)
723 "A function to filter out ANSI escape sequences.")
725 (defalias 'elpher-color-apply
726 (if (fboundp 'xterm-color-filter)
729 "A function to apply ANSI escape sequences.")
731 ;;; Processing text for display
733 (defun elpher-process-text-for-display (string)
734 "Perform any desired processing of STRING prior to display as text.
735 Currently includes buttonifying URLs and processing ANSI escape codes."
736 (elpher-buttonify-urls (if elpher-filter-ansi-from-text
737 (elpher-color-filter-apply string)
738 (elpher-color-apply string))))
741 ;;; Network error reporting
744 (defun elpher-network-error (address error)
745 "Display ERROR message following unsuccessful negotiation with ADDRESS.
746 ERROR can be either an error object or a string."
747 (elpher-with-clean-buffer
748 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
749 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
750 (if (stringp error) error (error-message-string error)) "\n"
751 (propertize "\n----------------\n\n" 'face 'error)
752 "Press 'u' to return to the previous page.")))
755 ;;; General network communication
758 (defvar elpher-network-timer nil
759 "Timer used for network connections.")
761 (defvar elpher-use-tls nil
762 "If non-nil, use TLS to communicate with gopher servers.")
764 (defvar elpher-client-certificate nil
765 "If non-nil, contains client certificate details to use for TLS connections.")
767 (defun elpher-process-cleanup ()
768 "Immediately shut down any extant elpher process and timers."
769 (let ((p (get-process "elpher-process")))
770 (if p (delete-process p)))
771 (if (timerp elpher-network-timer)
772 (cancel-timer elpher-network-timer)))
774 (defun elpher-make-network-timer (thunk)
775 "Create a timer to run the THUNK after `elpher-connection-timeout' seconds.
776 This is just a wraper around `run-at-time' which additionally sets the
777 buffer-local variable `elpher-network-timer' to allow
778 `elpher-process-cleanup' to also clear the timer."
779 (let ((timer (run-at-time elpher-connection-timeout nil thunk)))
780 (setq-local elpher-network-timer timer)
783 (defun elpher-get-host-response (address default-port query-string response-processor
784 &optional use-tls force-ipv4)
785 "Generic function for retrieving data from ADDRESS.
787 When ADDRESS lacks a specific port, DEFAULT-PORT is used instead.
788 QUERY-STRING is a string sent to the host specified by ADDRESS to
789 illicet a response. This response is passed as an argument to the
790 function RESPONSE-PROCESSOR.
792 If non-nil, USE-TLS specifies that the connection is to be made over
793 TLS. If set to gemini, the certificate verification will be disabled
794 unless `elpher-gemini-TLS-cert-checks' is non-nil.
796 If non-nil, FORCE-IPV4 causes the network connection to be made over
797 ipv4 only. (The default behaviour when this is not set depends on
798 the host operating system and the local network capabilities.)"
799 (if (and use-tls (not (gnutls-available-p)))
800 (error "Use of TLS requires Emacs to be compiled with GNU TLS support")
801 (unless (< (elpher-address-port address) 65536)
802 (error "Cannot establish network connection: port number > 65536"))
803 (when (and (eq use-tls 'gemini) (not elpher-gemini-TLS-cert-checks))
804 (setq-local network-security-level 'low)
805 (setq-local gnutls-verify-error nil))
807 (let* ((kill-buffer-query-functions nil)
808 (port (elpher-address-port address))
809 (host (elpher-address-host address))
810 (service (if (> port 0) port default-port))
811 (response-string-parts nil)
814 (socks (or elpher-socks-always (string-suffix-p ".onion" host)))
815 (gnutls-params (list :type 'gnutls-x509pki
818 (elpher-get-current-keylist address)))
819 (timer (elpher-make-network-timer
821 (elpher-process-cleanup)
823 ; Try again with IPv4
824 ((not (or elpher-ipv4-always force-ipv4 socks))
825 (message "Connection timed out. Retrying with IPv4.")
826 (elpher-get-host-response address default-port
831 (not (eq use-tls 'gemini))
832 (or elpher-auto-disengage-TLS
834 "TLS connetion failed. Disable TLS mode and retry? ")))
835 (setq elpher-use-tls nil)
836 (elpher-get-host-response address default-port
841 (elpher-network-error address "Connection time-out."))))))
842 (proc (if socks (socks-open-network-stream "elpher-process" nil host service)
843 (make-network-process :name "elpher-process"
845 :family (and (or force-ipv4
853 (cons 'gnutls-x509pki
854 (apply #'gnutls-boot-parameters
856 (setq elpher-network-timer timer)
857 (set-process-coding-system proc 'binary 'binary)
858 (set-process-query-on-exit-flag proc nil)
859 (elpher-buffer-message (concat "Connecting to " host "..."
860 " (press 'u' to abort)"))
861 (set-process-filter proc
862 (lambda (_proc string)
866 (setq bytes-received (+ bytes-received (length string)))
867 (let ((new-hkbytes-received (/ bytes-received 102400)))
868 (when (> new-hkbytes-received hkbytes-received)
869 (setq hkbytes-received new-hkbytes-received)
870 (elpher-buffer-message
872 (number-to-string (/ hkbytes-received 10.0))
875 (setq response-string-parts
876 (cons string response-string-parts))))
877 (set-process-sentinel proc
880 (cancel-timer timer))
881 (condition-case the-error
883 ((string-prefix-p "open" event) ; request URL
884 (elpher-buffer-message
885 (concat "Connected to " host ". Receiving data..."
886 " (press 'u' to abort)"))
887 (let ((inhibit-eol-conversion t))
888 (process-send-string proc query-string)))
889 ((string-prefix-p "deleted" event)) ; do nothing
890 ((and (not response-string-parts)
891 (not (or elpher-ipv4-always force-ipv4 socks)))
892 ; Try again with IPv4
893 (message "Connection failed. Retrying with IPv4.")
894 (elpher-get-host-response address default-port
898 (response-string-parts
899 (elpher-with-clean-buffer
900 (insert "Data received. Rendering..."))
901 (funcall response-processor
902 (apply #'concat (reverse response-string-parts)))
903 (elpher-restore-pos))
905 (error "No response from server")))
907 (elpher-network-error address the-error)))))
909 (if use-tls (apply #'gnutls-negotiate :process proc gnutls-params))
910 (funcall (process-sentinel proc) proc "open\n")))
912 (elpher-process-cleanup)
913 (error "Error initiating connection to server")))))
916 ;;; Client-side TLS Certificate Management
919 (defun elpher-generate-certificate (common-name key-file cert-file &optional temporary)
920 "Generate a key and a self-signed client TLS certificate using openssl.
922 The Common Name field of the certificate is set to COMMON-NAME. The
923 arguments KEY-FILE and CERT-FILE should contain the absolute paths of
924 the key and certificate files to write.
926 If TEMPORARY is non-nil, the certificate will be given an exporation
927 period of one day, and the key and certificate files will be deleted
928 when the certificate is no longer needed for the current session.
930 Otherwise, the certificate will be given a 100 year expiration period
931 and the files will not be deleted.
933 The function returns a list containing the current host name, the
934 temporary flag, and the key and cert file names in the form required
935 by `gnutls-boot-parameters`."
936 (let ((exp-key-file (expand-file-name key-file))
937 (exp-cert-file (expand-file-name cert-file)))
940 (call-process elpher-openssl-command nil nil nil
941 "req" "-x509" "-newkey" "rsa:2048"
942 "-days" (if temporary "1" "36500")
944 "-subj" (concat "/CN=" common-name)
945 "-keyout" exp-key-file
946 "-out" exp-cert-file)
947 (list (elpher-address-host (elpher-page-address elpher-current-page))
948 temporary exp-key-file exp-cert-file))
950 (message "Check that openssl is installed, or customize `elpher-openssl-command`.")
951 (error "Program 'openssl', required for certificate generation, not found")))))
953 (defun elpher-generate-throwaway-certificate ()
954 "Generate and return details of a throwaway certificate.
955 The key and certificate files will be deleted when they are no
956 longer needed for this session."
957 (let* ((file-base (make-temp-name "elpher"))
958 (key-file (concat temporary-file-directory file-base ".key"))
959 (cert-file (concat temporary-file-directory file-base ".crt")))
960 (elpher-generate-certificate file-base key-file cert-file t)))
962 (defun elpher-generate-persistent-certificate (file-base common-name)
963 "Generate and return details of a persistent certificate.
964 The argument FILE-BASE is used as the base for the key and certificate
965 files, while COMMON-NAME specifies the common name field of the
968 The key and certificate files are written to in `elpher-certificate-directory'."
969 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
970 (cert-file (concat elpher-certificate-directory file-base ".crt")))
971 (elpher-generate-certificate common-name key-file cert-file)))
973 (defun elpher-get-existing-certificate (file-base)
974 "Return a certificate object corresponding to an existing certificate.
975 It is assumed that the key files FILE-BASE.key and FILE-BASE.crt exist in
976 the directory `elpher-certificate-directory'."
977 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
978 (cert-file (concat elpher-certificate-directory file-base ".crt")))
979 (list (elpher-address-host (elpher-page-address elpher-current-page))
981 (expand-file-name key-file)
982 (expand-file-name cert-file))))
984 (defun elpher-install-and-use-existing-certificate (key-file-src cert-file-src file-base)
985 "Install a key+certificate file pair in `elpher-certificate-directory'.
986 The strings KEY-FILE-SRC and CERT-FILE-SRC are the existing key and
987 certificate files to install. The argument FILE-BASE is used as the
988 base for the installed key and certificate files."
989 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
990 (cert-file (concat elpher-certificate-directory file-base ".crt")))
991 (if (or (file-exists-p key-file)
992 (file-exists-p cert-file))
993 (error "A certificate with base name %s is already installed" file-base))
994 (copy-file key-file-src key-file)
995 (copy-file cert-file-src cert-file)
996 (list (elpher-address-host (elpher-page-address elpher-current-page))
998 (expand-file-name key-file)
999 (expand-file-name cert-file))))
1001 (defun elpher-list-existing-certificates ()
1002 "Return a list of the persistent certificates in `elpher-certificate-directory'."
1003 (unless (file-directory-p elpher-certificate-directory)
1004 (make-directory elpher-certificate-directory))
1007 (file-name-sans-extension file))
1008 (directory-files elpher-certificate-directory nil "\\.key$")))
1010 (defun elpher-forget-current-certificate ()
1011 "Causes any current certificate to be forgotten.)
1012 In the case of throwaway certificates, the key and certificate files
1015 (when elpher-client-certificate
1016 (unless (and (called-interactively-p 'any)
1017 (not (y-or-n-p (concat "Really forget client certificate? "
1018 "(Throwaway certificates will be deleted.)"))))
1019 (when (cadr elpher-client-certificate)
1020 (delete-file (elt elpher-client-certificate 2))
1021 (delete-file (elt elpher-client-certificate 3)))
1022 (setq elpher-client-certificate nil)
1023 (if (called-interactively-p 'any)
1024 (message "Client certificate forgotten.")))))
1026 (defun elpher-get-current-keylist (address)
1027 "Retrieve the `gnutls-boot-parameters'-compatable keylist.
1029 This is obtained from the client certificate described by
1030 `elpher-current-certificate', if one is available and the host for
1031 that certificate matches the host in ADDRESS.
1033 If `elpher-current-certificate' is non-nil, and its host name doesn't
1034 match that of ADDRESS, the certificate is forgotten."
1035 (if elpher-client-certificate
1036 (if (string= (car elpher-client-certificate)
1037 (elpher-address-host address))
1038 (list (cddr elpher-client-certificate))
1039 (elpher-forget-current-certificate)
1040 (message "Disabling client certificate for new host")
1045 ;;; Gopher selector retrieval
1048 (defun elpher-get-gopher-response (address renderer)
1049 "Get response string from gopher server at ADDRESS and render using RENDERER."
1050 (elpher-get-host-response address 70
1051 (concat (elpher-gopher-address-selector address) "\r\n")
1053 (or (string= (elpher-address-protocol address) "gophers")
1056 (defun elpher-get-gopher-page (renderer)
1057 "Getter function for gopher pages.
1058 The RENDERER procedure is used to display the contents of the page
1059 once they are retrieved from the gopher server."
1060 (let* ((address (elpher-page-address elpher-current-page))
1061 (content (elpher-get-cached-content address)))
1062 (if (and content (funcall renderer nil))
1063 (elpher-with-clean-buffer
1065 (elpher-restore-pos))
1066 (elpher-with-clean-buffer
1067 (insert "LOADING... (use 'u' to cancel)\n"))
1068 (condition-case the-error
1069 (elpher-get-gopher-response address renderer)
1071 (elpher-network-error address the-error))))))
1075 (defun elpher-insert-margin (&optional type-name)
1076 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
1079 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
1081 (propertize "[" 'face 'elpher-margin-brackets)
1082 (propertize type-name 'face 'elpher-margin-key)
1083 (propertize "]" 'face 'elpher-margin-brackets))))
1085 (insert (make-string elpher-margin-width ?\s))))
1087 (defun elpher--page-button-help (_window buffer pos)
1088 "Function called by Emacs to generate mouse-over text.
1089 The arguments specify the BUFFER and the POS within the buffer of the item
1090 for which help is required. The function returns the help to be
1091 displayed. The _WINDOW argument is currently unused."
1092 (with-current-buffer buffer
1093 (let ((button (button-at pos)))
1095 (let* ((page (button-get button 'elpher-page))
1096 (address (elpher-page-address page)))
1097 (format "mouse-1, RET: open '%s'" (elpher-address-to-url address)))))))
1099 (defun elpher-insert-index-record (display-string &optional address)
1100 "Function to insert an index record into the current buffer.
1101 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
1102 If ADDRESS is not supplied or nil the record is rendered as an
1103 'information' line."
1104 (let* ((type (if address (elpher-address-type address) nil))
1105 (type-map-entry (cdr (assoc type elpher-type-map))))
1107 (let* ((margin-code (elt type-map-entry 2))
1108 (face (elt type-map-entry 3))
1109 (filtered-display-string (elpher-color-filter-apply display-string))
1110 (page (elpher-make-page filtered-display-string address)))
1111 (elpher-insert-margin margin-code)
1112 (insert-text-button filtered-display-string
1115 'action #'elpher-click-link
1117 'help-echo #'elpher--page-button-help))
1119 ('nil ;; Information
1120 (elpher-insert-margin)
1121 (let ((propertized-display-string
1122 (propertize display-string 'face 'elpher-info)))
1123 (insert (elpher-process-text-for-display propertized-display-string))))
1124 (`(gopher ,selector-type) ;; Unknown
1125 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
1126 (insert (propertize display-string
1127 'face 'elpher-unknown)))))
1130 (defun elpher-click-link (button)
1131 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
1132 (let ((page (button-get button 'elpher-page)))
1133 (elpher-visit-page page)))
1135 (defun elpher-render-index (data &optional _mime-type-string)
1136 "Render DATA as an index. MIME-TYPE-STRING is unused."
1137 (elpher-with-clean-buffer
1140 (let ((data-processed (elpher-preprocess-text-response data)))
1141 (dolist (line (split-string data-processed "\n"))
1143 (unless (= (length line) 0)
1144 (let* ((type (elt line 0))
1145 (fields (split-string (substring line 1) "\t"))
1146 (display-string (elt fields 0))
1147 (selector (elt fields 1))
1148 (host (elt fields 2))
1149 (port (if (elt fields 3)
1150 (string-to-number (elt fields 3))
1152 (address (elpher-make-gopher-address type selector host port)))
1153 (elpher-insert-index-record display-string address))))))
1154 (elpher-cache-content (elpher-page-address elpher-current-page)
1159 (defun elpher-render-text (data &optional _mime-type-string)
1160 "Render DATA as text. MIME-TYPE-STRING is unused."
1161 (elpher-with-clean-buffer
1164 (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
1165 (elpher-cache-content
1166 (elpher-page-address elpher-current-page)
1171 (defun elpher-render-image (data &optional _mime-type-string)
1172 "Display DATA as image. MIME-TYPE-STRING is unused."
1175 (if (display-images-p)
1176 (let* ((image (create-image
1180 (error "Unsupported image format")
1181 (let ((window (get-buffer-window elpher-buffer-name)))
1183 (setf (image-property image :max-width) (window-body-width window t))
1184 (setf (image-property image :max-height) (window-body-height window t))))
1185 (elpher-with-clean-buffer
1186 (insert-image image)
1187 (elpher-restore-pos))))
1188 (elpher-render-download data))))
1190 ;; Search retrieval and rendering
1192 (defun elpher-get-gopher-query-page (renderer)
1193 "Getter for gopher addresses requiring input.
1194 The response is rendered using the rendering function RENDERER."
1195 (let* ((address (elpher-page-address elpher-current-page))
1196 (content (elpher-get-cached-content address))
1198 (if (and content (funcall renderer nil))
1199 (elpher-with-clean-buffer
1201 (elpher-restore-pos)
1202 (message "Displaying cached search results. Reload to perform a new search."))
1204 (let* ((query-string (read-string "Query: "))
1205 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
1206 (search-address (elpher-make-gopher-address ?1
1208 (elpher-address-host address)
1209 (elpher-address-port address)
1210 (equal (elpher-address-type address) "gophers"))))
1213 (elpher-with-clean-buffer
1214 (insert "LOADING RESULTS... (use 'u' to cancel)"))
1215 (elpher-get-gopher-response search-address renderer))
1217 (elpher-visit-previous-page))))))
1219 ;; Raw server response rendering
1221 (defun elpher-render-raw (data &optional mime-type-string)
1222 "Display raw DATA in buffer. MIME-TYPE-STRING is also displayed if provided."
1225 (elpher-with-clean-buffer
1226 (when mime-type-string
1227 (insert "MIME type specified by server: '" mime-type-string "'\n"))
1229 (goto-char (point-min)))
1230 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
1232 ;; File save "rendering"
1234 (defun elpher-render-download (data &optional _mime-type-string)
1235 "Save DATA to file. MIME-TYPE-STRING is unused."
1238 (let* ((address (elpher-page-address elpher-current-page))
1239 (selector (if (elpher-address-gopher-p address)
1240 (elpher-gopher-address-selector address)
1241 (elpher-address-filename address))))
1242 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1243 (let* ((filename-proposal (file-name-nondirectory selector))
1244 (filename (read-file-name "Download complete. Save file as: "
1246 (if (> (length filename-proposal) 0)
1249 (let ((coding-system-for-write 'binary))
1250 (with-temp-file filename
1252 (message (format "Saved to file %s." filename))))))
1256 (defun elpher-render-html (data &optional _mime-type-string)
1257 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
1258 (elpher-with-clean-buffer
1261 (let ((dom (with-temp-buffer
1263 (libxml-parse-html-region (point-min) (point-max)))))
1264 (shr-insert-document dom)))))
1266 ;; Gemini page retrieval
1268 (defvar elpher-gemini-redirect-chain)
1270 (defun elpher-get-gemini-response (address renderer)
1271 "Get response string from gemini server at ADDRESS and render using RENDERER."
1272 (elpher-get-host-response address 1965
1273 (concat (elpher-address-to-url address) "\r\n")
1274 (lambda (response-string)
1275 (elpher-process-gemini-response response-string renderer))
1278 (defun elpher-parse-gemini-response (response)
1279 "Parse the RESPONSE string and return a list of components.
1280 The list is of the form (code meta body). A response of nil implies
1281 that the response was malformed."
1282 (let ((header-end-idx (string-match "\r\n" response)))
1284 (let ((header (string-trim (substring response 0 header-end-idx)))
1285 (body (substring response (+ header-end-idx 2))))
1286 (if (>= (length header) 2)
1287 (let ((code (substring header 0 2))
1288 (meta (string-trim (substring header 2))))
1289 (list code meta body))
1290 (error "Malformed response: No response status found in header %s" header)))
1291 (error "Malformed response: No CRLF-delimited header found in response %s" response))))
1293 (defun elpher-process-gemini-response (response-string renderer)
1294 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
1295 (let ((response-components (elpher-parse-gemini-response response-string)))
1296 (let ((response-code (elt response-components 0))
1297 (response-meta (elt response-components 1))
1298 (response-body (elt response-components 2)))
1299 (pcase (elt response-code 0)
1300 (?1 ; Input required
1301 (elpher-with-clean-buffer
1302 (insert "Gemini server is requesting input."))
1303 (let* ((query-string
1304 (if (eq (elt response-code 1) ?1)
1305 (read-passwd (concat response-meta ": "))
1306 (read-string (concat response-meta ": "))))
1307 (query-address (seq-copy (elpher-page-address elpher-current-page)))
1308 (old-fname (url-filename query-address)))
1309 (setf (url-filename query-address)
1310 (concat old-fname "?" (url-build-query-string `((,query-string)))))
1311 (elpher-get-gemini-response query-address renderer)))
1312 (?2 ; Normal response
1313 (funcall renderer response-body response-meta))
1315 (message "Following redirect to %s" response-meta)
1316 (if (>= (length elpher-gemini-redirect-chain) 5)
1317 (error "More than 5 consecutive redirects followed"))
1318 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
1319 (if (member redirect-address elpher-gemini-redirect-chain)
1320 (error "Redirect loop detected"))
1321 (if (not (eq (elpher-address-type redirect-address) 'gemini))
1322 (error "Server tried to automatically redirect to non-gemini URL: %s"
1324 (elpher-page-set-address elpher-current-page redirect-address)
1325 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
1326 (elpher-get-gemini-response redirect-address renderer)))
1327 (?4 ; Temporary failure
1328 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
1329 response-code response-meta))
1330 (?5 ; Permanent failure
1331 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
1332 response-code response-meta))
1333 (?6 ; Client certificate required
1334 (elpher-with-clean-buffer
1335 (if elpher-client-certificate
1336 (insert "Gemini server does not recognise the provided TLS certificate:\n\n")
1337 (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
1339 (elpher-gemini-insert-text response-meta))
1340 (let ((chosen-certificate (elpher-choose-client-certificate)))
1341 (unless chosen-certificate
1342 (error "Gemini server requires a client certificate and none was provided"))
1343 (setq elpher-client-certificate chosen-certificate))
1344 (elpher-with-clean-buffer)
1345 (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer))
1347 (error "Gemini server response unknown: %s %s"
1348 response-code response-meta))))))
1350 (defun elpher--read-answer-polyfill (question answers)
1351 "Polyfill for `read-answer' in Emacs 26.1.
1352 QUESTION is a string containing a question, and ANSWERS
1353 is a list of possible answers."
1354 (completing-read question (mapcar 'identity answers)))
1356 (if (fboundp 'read-answer)
1357 (defalias 'elpher-read-answer 'read-answer)
1358 (defalias 'elpher-read-answer 'elpher--read-answer-polyfill))
1360 (defun elpher-choose-client-certificate ()
1361 "Prompt for a client certificate to use to establish a TLS connection."
1362 (let* ((read-answer-short t))
1363 (pcase (read-answer "What do you want to do? "
1365 "generate and use throw-away certificate")
1367 "generate new or use existing persistent certificate")
1369 "stop immediately")))
1371 (setq elpher-client-certificate (elpher-generate-throwaway-certificate)))
1373 (let* ((existing-certificates (elpher-list-existing-certificates))
1374 (file-base (completing-read
1375 "Nickname for new or existing certificate (autocompletes, empty response aborts): "
1376 existing-certificates)))
1377 (if (string-empty-p (string-trim file-base))
1379 (if (member file-base existing-certificates)
1380 (setq elpher-client-certificate
1381 (elpher-get-existing-certificate file-base))
1382 (pcase (read-answer "Generate new certificate or install externally-generated one? "
1384 "generate new certificate")
1386 "install existing certificate")
1388 "stop immediately")))
1390 (let ((common-name (read-string "Common Name field for new certificate: "
1392 (message "New key and self-signed certificate written to %s"
1393 elpher-certificate-directory)
1394 (elpher-generate-persistent-certificate file-base common-name)))
1396 (let* ((cert-file (read-file-name "Certificate file: " nil nil t))
1397 (key-file (read-file-name "Key file: " nil nil t)))
1398 (message "Key and certificate installed in %s for future use"
1399 elpher-certificate-directory)
1400 (elpher-install-and-use-existing-certificate key-file
1406 (defun elpher-get-gemini-page (renderer)
1407 "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
1408 (let* ((address (elpher-page-address elpher-current-page))
1409 (content (elpher-get-cached-content address)))
1410 (condition-case the-error
1411 (if (and content (funcall renderer nil))
1412 (elpher-with-clean-buffer
1414 (elpher-restore-pos))
1415 (elpher-with-clean-buffer
1416 (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
1417 (setq elpher-gemini-redirect-chain nil)
1418 (elpher-get-gemini-response address renderer))
1420 (elpher-network-error address the-error)))))
1422 (defun elpher-render-gemini (body &optional mime-type-string)
1423 "Render gemini response BODY with rendering MIME-TYPE-STRING."
1426 (let* ((mime-type-string* (if (or (not mime-type-string)
1427 (string-empty-p mime-type-string))
1428 "text/gemini; charset=utf-8"
1430 (mime-type-split (split-string mime-type-string* ";" t))
1431 (mime-type (string-trim (car mime-type-split)))
1432 (parameters (mapcar (lambda (s)
1433 (let ((key-val (split-string s "=")))
1434 (list (downcase (string-trim (car key-val)))
1435 (downcase (string-trim (cadr key-val))))))
1436 (cdr mime-type-split))))
1437 (when (string-prefix-p "text/" mime-type)
1438 (setq body (decode-coding-string
1440 (if (assoc "charset" parameters)
1441 (intern (cadr (assoc "charset" parameters)))
1443 (setq body (replace-regexp-in-string "\r" "" body)))
1445 ((or "text/gemini" "")
1446 (elpher-render-gemini-map body parameters))
1448 (elpher-render-html body))
1449 ((pred (string-prefix-p "text/"))
1450 (elpher-render-gemini-plain-text body parameters))
1451 ((pred (string-prefix-p "image/"))
1452 (elpher-render-image body))
1454 (elpher-render-download body))))))
1456 (defun elpher-gemini-get-link-url (link-line)
1457 "Extract the url portion of LINK-LINE, a gemini map file link line.
1458 Returns nil in the event that the contents of the line following the
1459 => prefix are empty."
1460 (let ((l (split-string (substring link-line 2))))
1462 (string-trim (elt l 0))
1465 (defun elpher-gemini-get-link-display-string (link-line)
1466 "Extract the display string portion of LINK-LINE, a gemini map file link line.
1467 Return nil if this portion is not provided."
1468 (let* ((rest (string-trim (elt (split-string link-line "=>") 1)))
1469 (idx (string-match "[ \t]" rest)))
1471 (elpher-color-filter-apply (string-trim (substring rest (+ idx 1)))))))
1473 (defun elpher-collapse-dot-sequences (filename)
1474 "Collapse dot sequences in the (absolute) FILENAME.
1475 For instance, the filename \"/a/b/../c/./d\" will reduce to \"/a/c/d\""
1476 (let* ((path (split-string filename "/" t))
1477 (is-directory (string-match-p (rx (: (or "." ".." "/") line-end)) filename))
1478 (path-reversed-normalized
1479 (seq-reduce (lambda (a b)
1480 (cond ((equal b "..") (cdr a))
1484 (path-normalized (reverse path-reversed-normalized)))
1486 (concat "/" (string-join path-normalized "/") (and is-directory "/"))
1489 (defun elpher-address-from-gemini-url (url)
1490 "Extract address from URL with defaults as per gemini map files.
1491 While there's obviously some redundancy here between this function and
1492 `elpher-address-from-url', gemini map file URLs require enough special
1493 treatment that a separate function is warranted."
1494 (let ((address (url-generic-parse-url url))
1495 (current-address (elpher-page-address elpher-current-page)))
1496 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
1497 (if (url-host address) ;if there is an explicit host, filenames are absolute
1498 (if (string-empty-p (url-filename address))
1499 (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
1500 (setf (url-host address) (url-host current-address))
1501 (setf (url-fullness address) (url-host address)) ; set fullness to t if host is set
1502 (setf (url-portspec address) (url-portspec current-address)) ; (url-port) too slow!
1503 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
1504 (setf (url-filename address)
1505 (concat (file-name-directory (url-filename current-address))
1506 (url-filename address)))))
1507 (when (url-host address)
1508 (setf (url-host address) (puny-encode-domain (url-host address))))
1509 (unless (url-type address)
1510 (setf (url-type address) (url-type current-address)))
1511 (when (equal (url-type address) "gemini")
1512 (setf (url-filename address)
1513 (elpher-collapse-dot-sequences (url-filename address)))))
1514 (elpher-remove-redundant-ports address)))
1516 (defun elpher-gemini-insert-link (link-line)
1517 "Insert link described by LINK-LINE into a text/gemini document."
1518 (let ((url (elpher-gemini-get-link-url link-line)))
1520 (let* ((given-display-string (elpher-gemini-get-link-display-string link-line))
1521 (address (elpher-address-from-gemini-url url))
1522 (type (if address (elpher-address-type address) nil))
1523 (type-map-entry (cdr (assoc type elpher-type-map)))
1524 (fill-prefix (make-string (+ 1 (length elpher-gemini-link-string)) ?\s)))
1525 (insert elpher-gemini-link-string)
1527 (let* ((face (elt type-map-entry 3))
1528 (display-string (or given-display-string
1529 (elpher-address-to-iri address)))
1530 (page (elpher-make-page display-string
1532 (insert-text-button display-string
1535 'action #'elpher-click-link
1537 'help-echo #'elpher--page-button-help))
1538 (insert (propertize display-string 'face 'elpher-unknown)))
1541 (defun elpher-gemini-insert-header (header-line)
1542 "Insert header described by HEADER-LINE into a text/gemini document.
1543 The gemini map file line describing the header is given
1545 (when (string-match "^\\(#+\\)[ \t]*" header-line)
1546 (let* ((level (length (match-string 1 header-line)))
1547 (header (substring header-line (match-end 0)))
1549 (1 'elpher-gemini-heading1)
1550 (2 'elpher-gemini-heading2)
1551 (3 'elpher-gemini-heading3)
1553 (fill-column (if (display-graphic-p)
1555 (font-get (font-spec :name (face-font 'default)) :size))
1556 (font-get (font-spec :name (face-font face)) :size)) fill-column)))
1557 (unless (display-graphic-p)
1558 (insert (make-string level ?#) " "))
1559 (insert (propertize header
1565 (defun elpher-gemini-insert-text (text-line)
1566 "Insert a plain non-preformatted TEXT-LINE into a text/gemini document.
1567 This function uses Emacs' auto-fill to wrap text sensibly to a maximum
1568 width defined by `elpher-gemini-max-fill-width'."
1572 (group (or (: "*" (+ (any " \t")))
1573 (: ">" (* (any " \t"))))))))
1575 (let* ((line-prefix (match-string 1 text-line))
1576 (processed-text-line
1578 (cond ((string-prefix-p "*" line-prefix)
1580 (replace-regexp-in-string "\\*"
1581 elpher-gemini-bullet-string
1582 (match-string 0 text-line))
1583 (substring text-line (match-end 0))))
1584 ((string-prefix-p ">" line-prefix)
1585 (propertize text-line 'face 'elpher-gemini-quoted))
1588 (fill-prefix (if line-prefix
1589 (make-string (length (match-string 0 text-line)) ?\s)
1591 (insert (elpher-process-text-for-display processed-text-line))
1594 (defun elpher-render-gemini-map (data _parameters)
1595 "Render DATA as a gemini map file, PARAMETERS is currently unused."
1596 (elpher-with-clean-buffer
1598 (let ((preformatted nil)
1599 (adaptive-fill-mode nil)) ;Prevent automatic setting of fill-prefix
1600 (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))
1601 (dolist (line (split-string data "\n"))
1603 ((string-prefix-p "```" line) (setq preformatted (not preformatted)))
1604 (preformatted (insert (elpher-process-text-for-display
1605 (propertize line 'face 'elpher-gemini-preformatted))
1607 ((string-prefix-p "=>" line)
1608 (elpher-gemini-insert-link line))
1609 ((string-prefix-p "#" line) (elpher-gemini-insert-header line))
1610 (t (elpher-gemini-insert-text line)))))
1611 (elpher-cache-content
1612 (elpher-page-address elpher-current-page)
1615 (defun elpher-render-gemini-plain-text (data _parameters)
1616 "Render DATA as plain text file. PARAMETERS is currently unused."
1617 (elpher-with-clean-buffer
1618 (insert (elpher-process-text-for-display data))
1619 (elpher-cache-content
1620 (elpher-page-address elpher-current-page)
1623 (defun elpher-build-current-imenu-index ()
1625 (goto-char (point-min))
1628 (while (setq match (text-property-search-forward 'gemini-heading t t))
1630 (buffer-substring-no-properties (prop-match-beginning match)
1631 (prop-match-end match))
1632 (prop-match-beginning match))
1634 (reverse headers))))
1636 ;; Finger page connection
1638 (defun elpher-get-finger-page (renderer)
1639 "Opens a finger connection to the current page address.
1640 The result is rendered using RENDERER."
1641 (let* ((address (elpher-page-address elpher-current-page))
1642 (content (elpher-get-cached-content address)))
1643 (if (and content (funcall renderer nil))
1644 (elpher-with-clean-buffer
1646 (elpher-restore-pos))
1647 (elpher-with-clean-buffer
1648 (insert "LOADING... (use 'u' to cancel)\n"))
1649 (condition-case the-error
1650 (let* ((kill-buffer-query-functions nil)
1651 (user (let ((filename (elpher-address-filename address)))
1652 (if (> (length filename) 1)
1653 (substring filename 1)
1654 (elpher-address-user address)))))
1655 (elpher-get-host-response address 79
1656 (concat user "\r\n")
1659 (elpher-network-error address the-error))))))
1662 ;; Telnet page connection
1664 (defun elpher-get-telnet-page (renderer)
1665 "Opens a telnet connection to the current page address (RENDERER must be nil)."
1667 (elpher-visit-previous-page)
1668 (error "Command not supported for telnet URLs"))
1669 (let* ((address (elpher-page-address elpher-current-page))
1670 (host (elpher-address-host address))
1671 (port (elpher-address-port address)))
1672 (elpher-visit-previous-page)
1678 ;; Other URL page opening
1680 (defun elpher-get-other-url-page (renderer)
1681 "Getter which attempts to open the URL specified by the current page (RENDERER must be nil)."
1683 (elpher-visit-previous-page)
1684 (error "Command not supported for general URLs"))
1685 (let* ((address (elpher-page-address elpher-current-page))
1686 (url (elpher-address-to-url address)))
1687 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1688 (message "Opening URL...")
1689 (if elpher-open-urls-with-eww
1695 (defun elpher-get-file-page (renderer)
1696 "Getter which renders a local file using RENDERER.
1697 Assumes UTF-8 encoding for all text files."
1698 (let* ((address (elpher-page-address elpher-current-page))
1699 (filename (elpher-address-filename address)))
1700 (unless (file-exists-p filename)
1701 (elpher-visit-previous-page)
1702 (error "File not found"))
1703 (unless (file-readable-p filename)
1704 (elpher-visit-previous-page)
1705 (error "Could not read from file"))
1706 (let ((body (with-temp-buffer
1707 (let ((coding-system-for-read 'binary)
1708 (coding-system-for-write 'binary))
1709 (insert-file-contents-literally filename)
1710 (encode-coding-string (buffer-string) 'raw-text)))))
1712 (funcall renderer body nil)
1713 (pcase (file-name-extension filename)
1714 ((or "gmi" "gemini")
1715 (elpher-render-gemini-map (decode-coding-string body 'utf-8) nil))
1717 (elpher-render-html (decode-coding-string body 'utf-8)))
1719 (elpher-render-text (decode-coding-string body 'utf-8)))
1720 ((or "jpg" "jpeg" "gif" "png" "bmp" "tif" "tiff")
1721 (elpher-render-image body))
1722 ((or "gopher" "gophermap")
1723 (elpher-render-index (elpher-decode body)))
1725 (elpher-render-download body))))
1726 (elpher-restore-pos))))
1729 ;; Welcome page retrieval
1731 (defun elpher-get-welcome-page (renderer)
1732 "Getter which displays the welcome page (RENDERER must be nil)."
1734 (elpher-visit-previous-page)
1735 (error "Command not supported for welcome page"))
1736 (elpher-with-clean-buffer
1737 (insert " --------------------------------------------\n"
1738 " Elpher Gopher and Gemini Client \n"
1739 " version " elpher-version "\n"
1740 " --------------------------------------------\n"
1742 "Default bindings:\n"
1744 " - TAB/Shift-TAB: next/prev item on current page\n"
1745 " - RET/mouse-1: open item under cursor\n"
1746 " - m: select an item on current page by name (autocompletes)\n"
1747 " - u/mouse-3/U: return to previous page or to the start page\n"
1748 " - g: go to a particular address (gopher, gemini, finger)\n"
1749 " - o/O: open a different address selector or the root menu of the current server\n"
1750 " - d/D: download item under cursor or current page\n"
1751 " - i/I: info on item under cursor or current page\n"
1752 " - c/C: copy URL representation of item under cursor or current page\n"
1753 " - a/A: bookmark the item under cursor or current page\n"
1754 " - B: list all bookmarks\n"
1755 " - s/S: show current history stack or all previously visted pages\n"
1756 " - r: redraw current page (using cached contents if available)\n"
1757 " - R: reload current page (regenerates cache)\n"
1758 " - !: set character coding system for gopher (default is to autodetect)\n"
1759 " - T: toggle TLS gopher mode\n"
1760 " - F: forget/discard current TLS client certificate\n"
1761 " - .: display the raw server response for the current page\n"
1763 "Start your exploration of gopher space and gemini:\n")
1764 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1765 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1766 (elpher-insert-index-record "Project Gemini home page"
1767 (elpher-address-from-url "gemini://gemini.circumlunar.space/"))
1769 "Alternatively, select a search engine and enter some search terms:\n")
1770 (elpher-insert-index-record "Gopher Search Engine (Veronica-2)"
1771 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1772 (elpher-insert-index-record "Gemini Search Engine (geminispace.info)"
1773 (elpher-address-from-url "gemini://geminispace.info/search"))
1775 "Your bookmarks are stored in your ")
1776 (insert-text-button "bookmark list"
1778 'action #'elpher-click-link
1780 'help-echo #'elpher--page-button-help
1782 (elpher-make-page "Elpher Bookmarks"
1783 (elpher-make-about-address 'bookmarks)))
1786 "(Bookmarks from legacy elpher-bookmarks files will be automatically imported.)\n"
1789 "The gopher home of the Elpher project is here:\n")
1790 (elpher-insert-index-record "The Elpher Project Page"
1791 (elpher-make-gopher-address ?1
1795 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1797 "The following info documentation is available:\n"
1799 (insert-text-button "Elpher Manual"
1805 'help-echo help-string)
1807 (insert-text-button "Changes introduced by the latest release"
1811 (info "(elpher)News"))
1813 'help-echo help-string))
1816 (concat "(These documents should be available if you have installed Elpher \n"
1817 " using MELPA. Otherwise you may have to install the manual yourself.)\n")
1819 (elpher-restore-pos)))
1821 ;; History page retrieval
1823 (defun elpher-show-history ()
1824 "Show the current contents of elpher's history stack.
1825 Use \\[elpher-show-visited-pages] to see the entire history.
1826 This is rendered using `elpher-get-history-page' via `elpher-type-map'."
1829 (elpher-make-page "Current History Stack"
1830 (elpher-make-about-address 'history))))
1832 (defun elpher-show-visited-pages ()
1833 "Show the all the pages you've visited using Elpher.
1834 Use \\[elpher-show-history] to see just the current history stack.
1835 This is rendered using `elpher-get-visited-pages-page' via `elpher-type-map'."
1838 (elpher-make-page "Elpher Visted Pages"
1839 (elpher-make-about-address 'visited-pages))))
1841 (defun elpher-get-history-page (renderer)
1842 "Getter which displays the history page (RENDERER must be nil)."
1844 (elpher-visit-previous-page)
1845 (error "Command not supported for history page"))
1846 (elpher-display-history-links elpher-history "Current history stack"))
1848 (defun elpher-get-visited-pages-page (renderer)
1849 "Getter which displays the list of visited pages (RENDERER must be nil)."
1851 (elpher-visit-previous-page)
1852 (error "Command not supported for history page"))
1853 (elpher-display-history-links
1854 (seq-filter (lambda (page)
1855 (not (elpher-address-about-p (elpher-page-address page))))
1856 elpher-visited-pages)
1857 "All visited pages"))
1859 (defun elpher-display-history-links (pages title)
1860 "Show all PAGES in an Elpher buffer with a given TITLE."
1861 (let* ((title-line (concat " ---- " title " ----"))
1862 (footer-line (make-string (length title-line) ?-)))
1863 (elpher-with-clean-buffer
1864 (insert title-line "\n\n")
1866 (dolist (page pages)
1868 (let ((display-string (elpher-page-display-string page))
1869 (address (elpher-page-address page)))
1870 (elpher-insert-index-record display-string address))))
1871 (insert "No history items found.\n"))
1872 (insert "\n " footer-line "\n"
1873 "Select an entry or press 'u' to return to the previous page.")
1874 (elpher-restore-pos))))
1879 ;; This code allows Elpher to use the standard Emacs bookmarks: `C-x r
1880 ;; m' to add a bookmark, `C-x r l' to list bookmarks (which is where
1881 ;; you can anotate bookmarks!), `C-x r b' to jump to a bookmark, and
1882 ;; so on. See the Bookmarks section in the Emacs info manual for more.
1884 (defvar elpher-bookmark-link nil
1885 "Prefer bookmarking a link or the current page.
1886 Bind this variable dynamically, or set it to t.
1887 If you set it to t, the commands \\[bookmark-set-no-overwrite]
1888 and \\[elpher-set-bookmark-no-overwrite] do the same thing.")
1890 (defun elpher-bookmark-make-record ()
1891 "Return a bookmark record.
1892 If `elpher-bookmark-link' is non-nil and point is on a link button,
1893 return a bookmark record for that link. Otherwise, return a bookmark
1894 record for the current elpher page."
1895 (let* ((button (and elpher-bookmark-link (button-at (point))))
1897 (button-get button 'elpher-page)
1898 elpher-current-page)))
1900 (error "Cannot bookmark this link"))
1901 (let* ((address (elpher-page-address page))
1902 (url (elpher-address-to-url address))
1903 (display-string (elpher-page-display-string page))
1904 (pos (if button nil (point))))
1905 (if (elpher-address-about-p address)
1906 (error "Cannot bookmark %s" display-string)
1908 (defaults . (,display-string))
1911 (handler . elpher-bookmark-jump))))))
1914 (defun elpher-bookmark-jump (bookmark)
1915 "Handler used to open a bookmark using elpher.
1916 The argument BOOKMARK is a bookmark record passed to the function.
1917 This handler is responsible for loading the bookmark in some buffer,
1918 then making that buffer the current buffer. It should not switch
1920 (let* ((url (cdr (assq 'location bookmark)))
1921 (cleaned-url (string-trim url))
1922 (page (elpher-page-from-url cleaned-url))
1923 (buffer (get-buffer-create elpher-buffer-name)))
1924 (elpher-with-clean-buffer
1925 (elpher-visit-page page))
1929 (defun elpher-bookmark-link ()
1930 "Bookmark the link at point.
1931 To bookmark the current page, use \\[elpher-bookmark-current]."
1933 (let ((elpher-bookmark-link t))
1934 (bookmark-set-no-overwrite)))
1936 (defun elpher-bookmark-current ()
1937 "Bookmark the current page.
1938 To bookmark the link at point use \\[elpher-bookmark-link]."
1940 (call-interactively #'bookmark-set-no-overwrite))
1942 (defun elpher-bookmark-import (file)
1943 "Import legacy Elpher bookmarks file FILE into Emacs bookmarks."
1944 (interactive (list (if (and (boundp 'elpher-bookmarks-file)
1945 (file-readable-p elpher-bookmarks-file))
1946 elpher-bookmarks-file
1947 (read-file-name "Old Elpher bookmarks: "
1948 user-emacs-directory nil t
1949 "elpher-bookmarks"))))
1950 (dolist (bookmark (with-temp-buffer
1951 (insert-file-contents file)
1952 (read (current-buffer))))
1953 (let* ((display-string (car bookmark))
1954 (url (cadr bookmark))
1955 (record `(,display-string
1957 (handler . elpher-bookmark-jump))))
1958 (bookmark-store display-string (cdr record) t)))
1961 (defun elpher-get-bookmarks-page (renderer)
1962 "Getter which displays the bookmarks (RENDERER must be nil)."
1964 (elpher-visit-previous-page)
1965 (error "Command not supported for bookmarks page"))
1967 (let ((old-bookmarks-file (or (and (boundp 'elpher-bookmarks-file)
1968 elpher-bookmarks-file)
1969 (locate-user-emacs-file "elpher-bookmarks"))))
1970 (when (and (file-readable-p old-bookmarks-file)
1971 (y-or-n-p (concat "Legacy elpher-bookmarks file \""
1973 "\" found. Import now?")))
1974 (elpher-bookmark-import old-bookmarks-file)
1975 (rename-file old-bookmarks-file (concat old-bookmarks-file "-legacy"))))
1977 (if (and elpher-use-emacs-bookmark-menu
1980 (elpher-visit-previous-page)
1981 (call-interactively #'bookmark-bmenu-list))
1982 (elpher-with-clean-buffer
1983 (insert " ---- Elpher Bookmarks ---- \n\n")
1984 (bookmark-maybe-load-default-file)
1985 (dolist (bookmark (bookmark-maybe-sort-alist))
1986 (when (eq #'elpher-bookmark-jump (alist-get 'handler (cdr bookmark)))
1987 (let* ((name (car bookmark))
1988 (url (alist-get 'location (cdr bookmark)))
1989 (address (elpher-address-from-url url)))
1990 (elpher-insert-index-record name address))))
1991 (when (<= (line-number-at-pos) 3)
1992 (insert "No bookmarked pages found.\n"))
1993 (insert "\n --------------------------\n\n"
1994 "Select an entry or press 'u' to return to the previous page.\n\n"
1995 "Bookmarks can be renamed or deleted via the ")
1996 (insert-text-button "Emacs bookmark menu"
1999 (call-interactively #'bookmark-bmenu-list))
2001 'help-echo "RET,mouse-1: open Emacs bookmark menu")
2002 (insert (substitute-command-keys
2003 ",\nwhich can also be opened from anywhere using '\\[bookmark-bmenu-list]'."))
2004 (elpher-restore-pos))))
2006 (defun elpher-show-bookmarks ()
2007 "Interactive function to display the current list of elpher bookmarks."
2010 (elpher-make-page "Elpher Bookmarks"
2011 (elpher-make-about-address 'bookmarks))))
2019 (defun elpher-org-export-link (link description format protocol)
2020 "Export a LINK with DESCRIPTION for the given PROTOCOL and FORMAT.
2022 FORMAT is an Org export backend. DESCRIPTION may be nil. PROTOCOL may be one
2023 of gemini, gopher or finger."
2024 (let* ((url (if (equal protocol "elpher")
2025 (string-remove-prefix "elpher:" link)
2026 (format "%s:%s" protocol link)))
2027 (desc (or description url)))
2029 (`gemini (format "=> %s %s" url desc))
2030 (`html (format "<a href=\"%s\">%s</a>" url desc))
2031 (`latex (format "\\href{%s}{%s}" url desc))
2032 (_ (if (not description)
2034 (format "%s (%s)" desc url))))))
2036 (defun elpher-org-store-link ()
2037 "Store link to an `elpher' page in Org."
2038 (when (eq major-mode 'elpher-mode)
2039 (let* ((url (elpher-info-current))
2040 (desc (car elpher-current-page))
2042 ((string-prefix-p "gemini:" url) "gemini")
2043 ((string-prefix-p "gopher:" url) "gopher")
2044 ((string-prefix-p "finger:" url) "finger")
2046 (when (equal "elpher" protocol)
2047 ;; Weird link. Or special inner link?
2048 (setq url (concat "elpher:" url)))
2049 (org-link-store-props :type protocol :link url :description desc)
2052 (defun elpher-org-follow-link (link protocol)
2053 "Visit a LINK for the given PROTOCOL.
2055 PROTOCOL may be one of gemini, gopher or finger. This method also
2056 supports the old protocol elpher, where the link is self-contained."
2057 (let ((url (if (equal protocol "elpher")
2058 (string-remove-prefix "elpher:" link)
2059 (format "%s:%s" protocol link))))
2062 (defun elpher-org-mode-integration ()
2063 "Set up `elpher' integration for `org-mode'."
2064 (org-link-set-parameters
2066 :store #'elpher-org-store-link
2067 :export (lambda (link description format _plist)
2068 (elpher-org-export-link link description format "elpher"))
2069 :follow (lambda (link _arg) (elpher-org-follow-link link "elpher")))
2070 (org-link-set-parameters
2072 :export (lambda (link description format _plist)
2073 (elpher-org-export-link link description format "gemini"))
2074 :follow (lambda (link _arg) (elpher-org-follow-link link "gemini")))
2075 (org-link-set-parameters
2077 :export (lambda (link description format _plist)
2078 (elpher-org-export-link link description format "gopher"))
2079 :follow (lambda (link _arg) (elpher-org-follow-link link "gopher")))
2080 (org-link-set-parameters
2082 :export (lambda (link description format _plist)
2083 (elpher-org-export-link link description format "finger"))
2084 :follow (lambda (link _arg) (elpher-org-follow-link link "finger"))))
2086 (add-hook 'org-mode-hook #'elpher-org-mode-integration)
2091 (defun elpher-browse-url-elpher (url &rest _args)
2092 "Browse URL using Elpher. This function is used by `browse-url'."
2093 (interactive (browse-url-interactive-arg "Elpher URL: "))
2096 ;; Use elpher to open gopher, finger and gemini links
2097 ;; For recent version of `browse-url' package
2098 (if (boundp 'browse-url-default-handlers)
2100 'browse-url-default-handlers
2101 '("^\\(gopher\\|finger\\|gemini\\)://" . elpher-browse-url-elpher))
2102 ;; Patch `browse-url-browser-function' for older ones. The value of
2103 ;; that variable is `browse-url-default-browser' by default, so
2104 ;; that's the function that gets advised. If the value is an alist,
2105 ;; however, we don't know what to do. Better not interfere?
2106 (when (and (symbolp browse-url-browser-function)
2107 (fboundp browse-url-browser-function))
2108 (advice-add browse-url-browser-function :before-while
2109 (lambda (url &rest _args)
2110 "Handle gemini, gopher, and finger schemes using Elpher."
2111 (let ((scheme (downcase (car (split-string url ":" t)))))
2112 (if (member scheme '("gemini" "gopher" "finger"))
2113 ;; `elpher-go' always returns nil, which will stop the
2114 ;; advice chain here in a before-while
2116 ;; chain must continue, then return t.
2119 ;; Register "gemini://" as a URI scheme so `browse-url' does the right thing
2120 (with-eval-after-load 'thingatpt
2121 (add-to-list 'thing-at-point-uri-schemes "gemini://"))
2125 ;; Make mu4e aware of the gemini world
2126 (setq mu4e~view-beginning-of-url-regexp
2127 "\\(?:https?\\|gopher\\|finger\\|gemini\\)://\\|mailto:")
2131 ;; Let elpher handle gemini, gopher links in eww buffer.
2132 (setq eww-use-browse-url
2133 "\\`mailto:\\|\\(\\`gemini\\|\\`gopher\\|\\`finger\\)://")
2136 ;;; Interactive procedures
2139 (defun elpher-next-link ()
2140 "Move point to the next link on the current page."
2144 (defun elpher-prev-link ()
2145 "Move point to the previous link on the current page."
2147 (backward-button 1))
2149 (defun elpher-follow-current-link ()
2150 "Open the link or url at point."
2155 (defun elpher-go (host-or-url)
2156 "Go to a particular gopher site HOST-OR-URL.
2157 When run interactively HOST-OR-URL is read from the minibuffer."
2159 (read-string (format "Visit URL (default scheme %s): " (elpher-get-default-url-scheme)))))
2160 (let ((trimmed-host-or-url (string-trim host-or-url)))
2161 (unless (string-empty-p trimmed-host-or-url)
2162 (let ((page (elpher-page-from-url trimmed-host-or-url
2163 (elpher-get-default-url-scheme))))
2164 (unless (get-buffer-window elpher-buffer-name t)
2165 (switch-to-buffer elpher-buffer-name))
2166 (elpher-with-clean-buffer
2167 (elpher-visit-page page))
2168 nil)))) ; non-nil value is displayed by eshell
2170 (defun elpher-go-current ()
2171 "Go to a particular site read from the minibuffer, initialized with the current URL."
2173 (let* ((address (elpher-page-address elpher-current-page))
2174 (url (read-string (format "Visit URL (default scheme %s): " (elpher-get-default-url-scheme))
2175 (elpher-address-to-url address))))
2176 (unless (string-empty-p (string-trim url))
2177 (elpher-visit-page (elpher-page-from-url url)))))
2179 (defun elpher-redraw ()
2180 "Redraw current page."
2182 (elpher-visit-page elpher-current-page))
2184 (defun elpher-reload ()
2185 "Reload current page."
2187 (elpher-reload-current-page))
2189 (defun elpher-toggle-tls ()
2190 "Toggle TLS encryption mode for gopher."
2192 (setq elpher-use-tls (not elpher-use-tls))
2194 (if (gnutls-available-p)
2195 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
2196 (setq elpher-use-tls nil)
2197 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
2198 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
2200 (defun elpher-view-raw ()
2201 "View raw server response for current page."
2203 (if (elpher-address-about-p (elpher-page-address elpher-current-page))
2204 (error "This page was not generated by a server")
2205 (elpher-visit-page elpher-current-page
2206 #'elpher-render-raw)))
2208 (defun elpher-back ()
2209 "Go to previous site."
2211 (elpher-visit-previous-page))
2213 (defun elpher-back-to-start ()
2214 "Go all the way back to the start page."
2216 (setq-local elpher-current-page nil)
2217 (setq-local elpher-history nil)
2218 (elpher-visit-page (elpher-make-start-page)))
2220 (defun elpher-download ()
2221 "Download the link at point."
2223 (let ((button (button-at (point))))
2225 (let ((page (button-get button 'elpher-page)))
2227 (error "Not an elpher page"))
2228 (when (elpher-address-about-p (elpher-page-address page))
2229 (error "Cannot download %s" (elpher-page-display-string page)))
2230 (elpher-visit-page (button-get button 'elpher-page)
2231 #'elpher-render-download))
2232 (error "No link selected"))))
2234 (defun elpher-download-current ()
2235 "Download the current page."
2237 (if (elpher-address-about-p (elpher-page-address elpher-current-page))
2238 (error "Cannot download %s"
2239 (elpher-page-display-string elpher-current-page))
2240 (elpher-visit-page (elpher-make-page
2241 (elpher-page-display-string elpher-current-page)
2242 (elpher-page-address elpher-current-page))
2243 #'elpher-render-download
2246 (defun elpher--build-link-map ()
2247 "Build alist mapping link names to destination pages in current buffer."
2248 (let ((link-map nil)
2249 (b (next-button (point-min) t)))
2251 (push (cons (button-label b) b) link-map)
2252 (setq b (next-button (button-start b))))
2255 (defun elpher-jump ()
2256 "Select a directory entry by name. Similar to the info browser (m)enu command."
2258 (let* ((link-map (elpher--build-link-map)))
2260 (let ((key (let ((completion-ignore-case t))
2261 (completing-read "Directory item/link: "
2263 (if (and key (> (length key) 0))
2264 (let ((b (cdr (assoc key link-map))))
2265 (goto-char (button-start b))
2266 (button-activate b)))))))
2268 (defun elpher-root-dir ()
2269 "Visit root of current server."
2271 (let ((address (elpher-page-address elpher-current-page)))
2272 (if (not (elpher-address-about-p address))
2273 (if (or (member (url-filename address) '("/" ""))
2274 (and (elpher-address-gopher-p address)
2275 (= (length (elpher-gopher-address-selector address)) 0)))
2276 (error "Already at root directory of current server")
2277 (let ((address-copy (elpher-address-from-url
2278 (elpher-address-to-url address))))
2279 (setf (url-filename address-copy) "")
2280 (elpher-go (elpher-address-to-url address-copy))))
2281 (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
2283 (defun elpher-info-page (page)
2284 "Display URL of PAGE in minibuffer."
2285 (let* ((address (elpher-page-address page))
2286 (url (elpher-address-to-url address))
2287 (iri (elpher-address-to-iri address)))
2290 (message "%s (Raw: %s)" iri url))))
2292 (defun elpher-info-link ()
2293 "Display information on page corresponding to link at point."
2295 (let ((button (button-at (point))))
2297 (error "No item selected"))
2298 (let ((page (button-get button 'elpher-page)))
2300 (error "Not an elpher page"))
2301 (elpher-info-page page))))
2303 (defun elpher-info-current ()
2304 "Display information on current page."
2306 (elpher-info-page elpher-current-page))
2308 (defun elpher-copy-page-url (page)
2309 "Copy URL representation of address of PAGE to `kill-ring'."
2310 (let* ((address (elpher-page-address page))
2311 (url (elpher-address-to-url address)))
2312 (message "Copied \"%s\" to kill-ring/clipboard." url)
2315 (defun elpher-copy-link-url ()
2316 "Copy URL of item at point to `kill-ring'."
2318 (let ((button (button-at (point))))
2320 (error "No item selected"))
2321 (let ((page (button-get button 'elpher-page)))
2323 (error "Not an elpher page"))
2324 (elpher-copy-page-url page))))
2326 (defun elpher-copy-current-url ()
2327 "Copy URL of current page to `kill-ring'."
2329 (elpher-copy-page-url elpher-current-page))
2331 (defun elpher-set-gopher-coding-system ()
2332 "Specify an explicit character coding system for gopher selectors."
2334 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
2335 (setq elpher-user-coding-system system)
2337 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
2338 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
2344 (defvar elpher-mode-map
2345 (let ((map (make-sparse-keymap)))
2346 (define-key map (kbd "TAB") 'elpher-next-link)
2347 (define-key map (kbd "<backtab>") 'elpher-prev-link)
2348 (define-key map (kbd "C-M-i") 'elpher-prev-link)
2349 (define-key map (kbd "u") 'elpher-back)
2350 (define-key map (kbd "-") 'elpher-back)
2351 (define-key map (kbd "^") 'elpher-back)
2352 (define-key map [mouse-3] 'elpher-back)
2353 (define-key map (kbd "U") 'elpher-back-to-start)
2354 (define-key map (kbd "g") 'elpher-go)
2355 (define-key map (kbd "o") 'elpher-go-current)
2356 (define-key map (kbd "O") 'elpher-root-dir)
2357 (define-key map (kbd "s") 'elpher-show-history)
2358 (define-key map (kbd "S") 'elpher-show-visited-pages)
2359 (define-key map (kbd "r") 'elpher-redraw)
2360 (define-key map (kbd "R") 'elpher-reload)
2361 (define-key map (kbd "T") 'elpher-toggle-tls)
2362 (define-key map (kbd ".") 'elpher-view-raw)
2363 (define-key map (kbd "d") 'elpher-download)
2364 (define-key map (kbd "D") 'elpher-download-current)
2365 (define-key map (kbd "m") 'elpher-jump)
2366 (define-key map (kbd "i") 'elpher-info-link)
2367 (define-key map (kbd "I") 'elpher-info-current)
2368 (define-key map (kbd "c") 'elpher-copy-link-url)
2369 (define-key map (kbd "C") 'elpher-copy-current-url)
2370 (define-key map (kbd "a") 'elpher-bookmark-link)
2371 (define-key map (kbd "A") 'elpher-bookmark-current)
2372 (define-key map (kbd "B") 'elpher-show-bookmarks)
2373 (define-key map (kbd "!") 'elpher-set-gopher-coding-system)
2374 (define-key map (kbd "F") 'elpher-forget-current-certificate)
2375 (when (fboundp 'evil-define-key*)
2378 (kbd "TAB") 'elpher-next-link
2379 (kbd "C-") 'elpher-follow-current-link
2380 (kbd "C-t") 'elpher-back
2381 (kbd "u") 'elpher-back
2382 (kbd "-") 'elpher-back
2383 (kbd "^") 'elpher-back
2384 [mouse-3] 'elpher-back
2385 (kbd "U") 'elpher-back-to-start
2386 (kbd "g") 'elpher-go
2387 (kbd "o") 'elpher-go-current
2388 (kbd "O") 'elpher-root-dir
2389 (kbd "s") 'elpher-show-history
2390 (kbd "S") 'elpher-show-visited-pages
2391 (kbd "r") 'elpher-redraw
2392 (kbd "R") 'elpher-reload
2393 (kbd "T") 'elpher-toggle-tls
2394 (kbd ".") 'elpher-view-raw
2395 (kbd "d") 'elpher-download
2396 (kbd "D") 'elpher-download-current
2397 (kbd "m") 'elpher-jump
2398 (kbd "i") 'elpher-info-link
2399 (kbd "I") 'elpher-info-current
2400 (kbd "c") 'elpher-copy-link-url
2401 (kbd "C") 'elpher-copy-current-url
2402 (kbd "a") 'elpher-bookmark-link
2403 (kbd "A") 'elpher-bookmark-current
2404 (kbd "B") 'elpher-show-bookmarks
2405 (kbd "!") 'elpher-set-gopher-coding-system
2406 (kbd "F") 'elpher-forget-current-certificate))
2408 "Keymap for gopher client.")
2410 (define-derived-mode elpher-mode special-mode "elpher"
2411 "Major mode for elpher, an elisp gopher client.
2413 This mode is automatically enabled by the interactive
2414 functions which initialize the client, namely
2415 `elpher', and `elpher-go'."
2416 (setq-local elpher-current-page nil)
2417 (setq-local elpher-history nil)
2418 (setq-local elpher-buffer-name (buffer-name))
2419 (setq-local bookmark-make-record-function #'elpher-bookmark-make-record)
2420 (setq-local imenu-create-index-function #'elpher-build-current-imenu-index))
2422 (when (fboundp 'evil-set-initial-state)
2423 (evil-set-initial-state 'elpher-mode 'motion))
2426 ;;; Main start procedure
2430 (defun elpher (&optional arg)
2431 "Start elpher with default landing page.
2432 The buffer used for Elpher sessions is determined by the value of
2433 ‘elpher-buffer-name’. If there is already an Elpher session active in
2434 that buffer, Emacs will simply switch to it. Otherwise, a new session
2435 will begin. A numeric prefix ARG (as in ‘\\[universal-argument] 42
2436 \\[execute-extended-command] elpher RET’) switches to the session with
2437 that number, creating it if necessary. A non numeric prefix ARG means
2438 to create a new session. Returns the buffer selected (or created)."
2440 (let* ((name (default-value 'elpher-buffer-name))
2441 (buf (cond ((numberp arg)
2442 (get-buffer-create (format "%s<%d>" name arg)))
2444 (generate-new-buffer name))
2446 (get-buffer-create name)))))
2447 (pop-to-buffer-same-window buf)
2448 (unless (buffer-modified-p)
2450 (elpher-visit-page (elpher-make-start-page))
2451 "Started Elpher."))); Otherwise (elpher) evaluates to start page string.
2453 ;;; elpher.el ends here