1 ;;; elpher.el --- A friendly gopher and gemini client -*- lexical-binding: t -*-
3 ;; Copyright (C) 2019-2023 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 gemini
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.
74 (defconst elpher-version "3.5.0"
75 "Current version of elpher.")
77 (defconst elpher-margin-width 6
78 "Width of left-hand margin used when rendering indicies.")
80 (defconst elpher-type-map
81 '(((gopher ?0) elpher-get-gopher-page elpher-render-text "txt" elpher-text)
82 ((gopher ?1) elpher-get-gopher-page elpher-render-index "/" elpher-index)
83 ((gopher ?4) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
84 ((gopher ?5) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
85 ((gopher ?7) elpher-get-gopher-query-page elpher-render-index "?" elpher-search)
86 ((gopher ?9) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
87 ((gopher ?g) elpher-get-gopher-page elpher-render-image "img" elpher-image)
88 ((gopher ?p) elpher-get-gopher-page elpher-render-image "img" elpher-image)
89 ((gopher ?I) elpher-get-gopher-page elpher-render-image "img" elpher-image)
90 ((gopher ?d) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
91 ((gopher ?P) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
92 ((gopher ?s) elpher-get-gopher-page elpher-render-download "snd" elpher-binary)
93 ((gopher ?h) elpher-get-gopher-page elpher-render-html "htm" elpher-html)
94 (gemini elpher-get-gemini-page elpher-render-gemini "gem" elpher-gemini)
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 (defcustom elpher-certificate-map nil
245 "Register client certificates to be used for gemini URLs.
246 This variable contains an alist representing a mapping between gemini
247 URLs and the names of client certificates which will be automatically
248 activated for those URLs. Beware that the certificates will also be
249 active for all subdirectories of the given URLs."
250 :type '(alist :key-type string :value-type string))
252 ;; Face customizations
254 (defgroup elpher-faces nil
255 "Elpher face customizations."
258 (defface elpher-index
259 '((t :inherit font-lock-keyword-face))
260 "Face used for directory type directory records.")
264 "Face used for text type directory records.")
267 '((t :inherit default))
268 "Face used for info type directory records.")
270 (defface elpher-image
271 '((t :inherit font-lock-string-face))
272 "Face used for image type directory records.")
274 (defface elpher-search
275 '((t :inherit warning))
276 "Face used for search type directory records.")
279 '((t :inherit font-lock-comment-face))
280 "Face used for html type directory records.")
282 (defface elpher-gemini
283 '((t :inherit font-lock-constant-face))
284 "Face used for Gemini type directory records.")
286 (defface elpher-other-url
287 '((t :inherit font-lock-comment-face))
288 "Face used for other URL type links records.")
290 (defface elpher-telnet
291 '((t :inherit font-lock-function-name-face))
292 "Face used for telnet type directory records.")
294 (defface elpher-binary
295 '((t :inherit font-lock-doc-face))
296 "Face used for binary type directory records.")
298 (defface elpher-unknown
299 '((t :inherit error))
300 "Face used for directory records with unknown/unsupported types.")
302 (defface elpher-margin-key
304 "Face used for directory margin key.")
306 (defface elpher-margin-brackets
307 '((t :inherit shadow))
308 "Face used for brackets around directory margin key.")
310 (defface elpher-gemini-heading1
311 '((t :inherit bold :height 1.8))
312 "Face used for gemini heading level 1.")
314 (defface elpher-gemini-heading2
315 '((t :inherit bold :height 1.5))
316 "Face used for gemini heading level 2.")
318 (defface elpher-gemini-heading3
319 '((t :inherit bold :height 1.2))
320 "Face used for gemini heading level 3.")
322 (defface elpher-gemini-quoted
323 '((t :inherit font-lock-doc-face))
324 "Face used for gemini quoted texts.")
326 (defface elpher-gemini-preformatted
327 '((t :inherit default))
328 "Face used for gemini preformatted text.")
330 (defface elpher-gemini-preformatted-toggle
331 '((t :inherit button))
332 "Face used for buttons used to toggle display of preformatted text.")
339 ;; An elpher "address" object is either a url object or a symbol.
340 ;; Addresses with the "about" type, corresponding to pages generated
341 ;; dynamically for and by elpher. All others represent pages which
342 ;; rely on content retrieved over the network.
344 (defun elpher-address-from-url (url-string &optional default-scheme)
345 "Create a ADDRESS object corresponding to the given URL-STRING.
346 If DEFAULT-SCHEME is non-nil, this sets the scheme of the URL when one
347 is not explicitly given."
348 (let ((data (match-data))) ; Prevent parsing clobbering match data
350 (let ((url (url-generic-parse-url url-string)))
351 (unless (and (not (url-fullness url)) (url-type url))
352 (unless (url-type url)
353 (setf (url-type url) default-scheme))
354 (unless (url-host url)
355 (let ((p (split-string (url-filename url) "/" nil nil)))
356 (setf (url-host url) (car p))
357 (setf (url-filename url)
359 (concat "/" (mapconcat #'identity (cdr p) "/"))
361 (when (not (string-empty-p (url-host url)))
362 (setf (url-fullness url) t)
363 (setf (url-host url) (puny-encode-domain (url-host url))))
364 (when (or (equal "gopher" (url-type url))
365 (equal "gophers" (url-type url)))
367 (when (or (equal (url-filename url) "")
368 (equal (url-filename url) "/"))
369 (setf (url-filename url) "/1")))
370 (when (equal "gemini" (url-type url))
372 (if (equal (url-filename url) "")
373 (setf (url-filename url) "/"))))
374 (elpher-remove-redundant-ports url))
375 (set-match-data data))))
377 (defun elpher-remove-redundant-ports (address)
378 "Remove redundant port specifiers from ADDRESS.
379 Here 'redundant' means that the specified port matches the default
380 for that protocol, eg 70 for gopher."
381 (if (and (not (elpher-address-about-p address))
382 (eq (url-portspec address) ; (url-port) is too slow!
383 (pcase (url-type address)
385 ((or "gopher" "gophers") 70)
388 (setf (url-portspec address) nil))
391 (defun elpher-make-gopher-address (type selector host port &optional tls)
392 "Create an ADDRESS object using gopher directory record attributes.
393 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
394 If the optional attribute TLS is non-nil, the address will be marked as
395 requiring gopher-over-TLS."
397 ((equal type ?i) nil)
398 ((and (equal type ?h)
399 (string-prefix-p "URL:" selector))
400 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
402 (elpher-address-from-url
405 ":" (number-to-string port))))
407 (elpher-address-from-url
408 (concat "gopher" (if tls "s" "")
410 ":" (number-to-string port)
414 (defun elpher-make-about-address (type)
415 "Create an ADDRESS object corresponding to the given about address TYPE."
416 (elpher-address-from-url (concat "about:" (symbol-name type))))
418 (defun elpher-address-to-url (address)
419 "Get string representation of ADDRESS."
420 (url-encode-url (url-recreate-url address)))
422 (defun elpher-address-type (address)
423 "Retrieve type of ADDRESS object.
424 This is used to determine how to retrieve and render the document the
425 address refers to, via the table `elpher-type-map'."
426 (pcase (url-type address)
428 (list 'about (intern (url-filename address))))
429 ((or "gopher" "gophers")
431 (if (member (url-filename address) '("" "/"))
433 (string-to-char (substring (url-filename address) 1)))))
440 (defun elpher-address-about-p (address)
441 "Return non-nil if ADDRESS is an about address."
442 (pcase (elpher-address-type address) (`(about ,_) t)))
444 (defun elpher-address-gopher-p (address)
445 "Return non-nil if ADDRESS object is a gopher address."
446 (pcase (elpher-address-type address) (`(gopher ,_) t)))
448 (defun elpher-address-protocol (address)
449 "Retrieve the transport protocol for ADDRESS."
452 (defun elpher-address-filename (address)
453 "Retrieve the filename component of ADDRESS.
454 For gopher addresses this is a combination of the selector type and selector."
455 (url-unhex-string (url-filename address)))
457 (defun elpher-address-host (address)
458 "Retrieve host from ADDRESS object."
459 (pcase (url-host address)
460 ;; The following strips out square brackets which sometimes enclose IPv6
461 ;; addresses. Doing this here rather than at the parsing stage may seem
462 ;; weird, but this lets us way we avoid having to muck with both URL parsing
463 ;; and reconstruction. It's also more efficient, as this method is not
464 ;; called during page rendering.
465 ((rx (: "[" (let ipv6 (* (not "]"))) "]"))
467 ;; The following is a work-around for a parsing bug that causes
468 ;; URLs with empty (but not absent, see RFC 1738) usernames to have
469 ;; @ prepended to the hostname.
470 ((rx (: "@" (let rest (+ anything))))
475 (defun elpher-address-user (address)
476 "Retrieve user from ADDRESS object."
479 (defun elpher-address-port (address)
480 "Retrieve port from ADDRESS object.
481 If no address is defined, returns 0. (This is for compatibility with
483 (let ((port (url-portspec address))) ; (url-port) is too slow!
486 (defun elpher-gopher-address-selector (address)
487 "Retrieve gopher selector from ADDRESS object."
488 (if (member (url-filename address) '("" "/"))
490 (url-unhex-string (substring (url-filename address) 2))))
495 (defvar elpher-content-cache (make-hash-table :test 'equal))
496 (defvar elpher-pos-cache (make-hash-table :test 'equal))
498 (defun elpher-get-cached-content (address)
499 "Retrieve the cached content for ADDRESS, or nil if none exists."
500 (gethash address elpher-content-cache))
502 (defun elpher-cache-content (address content)
503 "Set the content cache for ADDRESS to CONTENT."
504 (puthash address content elpher-content-cache))
506 (defun elpher-get-cached-pos (address)
507 "Retrieve the cached cursor position for ADDRESS, or nil if none exists."
508 (gethash address elpher-pos-cache))
510 (defun elpher-cache-pos (address pos)
511 "Set the cursor position cache for ADDRESS to POS."
512 (puthash address pos elpher-pos-cache))
517 (defun elpher-make-page (display-string address)
518 "Create a page with DISPLAY-STRING and ADDRESS."
519 (list display-string address))
521 (defun elpher-make-start-page ()
522 "Create the start page."
523 (elpher-make-page "Start Page"
524 (elpher-address-from-url elpher-start-page-url)))
526 (defun elpher-page-display-string (page)
527 "Retrieve the display string corresponding to PAGE."
530 (defun elpher-page-address (page)
531 "Retrieve the address corresponding to PAGE."
534 (defun elpher-page-set-address (page new-address)
535 "Set the address corresponding to PAGE to NEW-ADDRESS."
536 (setcar (cdr page) new-address))
538 (defun elpher-page-from-url (url &optional default-scheme)
539 "Create a page with address and display string defined by URL.
540 The URL is unhexed prior to its use as a display string to improve
543 If DEFAULT-SCHEME is non-nil, this scheme is applied to the URL
544 in the instance that URL itself doesn't specify one."
545 (let ((address (elpher-address-from-url url default-scheme)))
546 (elpher-make-page (elpher-address-to-iri address) address)))
548 (defun elpher-address-to-iri (address)
549 "Return an IRI for ADDRESS.
550 Decode percent-escapes and handle punycode in the domain name.
551 Drop the password, if any."
552 (let ((data (match-data)) ; Prevent parsing clobbering match data
553 (host (url-host address))
554 (pass (url-password address)))
556 (let* ((host (url-host address))
557 (pass (url-password address)))
559 (setf (url-host address) (puny-decode-domain host)))
560 (when pass ; RFC 3986 says we should not render
561 (setf (url-password address) nil)) ; the password as clear text
562 (elpher-decode (url-unhex-string (url-recreate-url address))))
563 (setf (url-host address) host)
564 (setf (url-password address) pass)
565 (set-match-data data))))
567 (defvar elpher-current-page nil
568 "The current page for this Elpher buffer.")
570 (defvar elpher-history nil
571 "The local history stack for this Elpher buffer.
572 This variable is used by `elpher-back' and
573 `elpher-show-history'.")
575 (defvar elpher-visited-pages nil
576 "The global history for all Elpher buffers.
577 This variable is used by `elpher-show-visited-pages'.")
579 (defun elpher-visit-page (page &optional renderer no-history)
580 "Visit PAGE using its own renderer or RENDERER, if non-nil.
581 Additionally, push PAGE onto the history stack and the list of
582 previously-visited pages, unless NO-HISTORY is non-nil."
584 (elpher-process-cleanup)
586 (unless (or (not elpher-current-page)
587 (equal (elpher-page-address elpher-current-page)
588 (elpher-page-address page)))
589 (push elpher-current-page elpher-history)
590 (unless (or (elpher-address-about-p (elpher-page-address page))
591 (and elpher-visited-pages
592 (equal page (car elpher-visited-pages))))
593 (push page elpher-visited-pages))))
594 (setq-local elpher-current-page page)
595 (let* ((address (elpher-page-address page))
596 (type (elpher-address-type address))
597 (type-record (cdr (assoc type elpher-type-map))))
599 (funcall (car type-record)
603 (elpher-visit-previous-page)
605 (`(gopher ,type-char)
606 (error "Unsupported gopher selector type '%c' for '%s'"
607 type-char (elpher-address-to-url address)))
609 (error "Unsupported address type '%S' for '%s'"
610 other (elpher-address-to-url address)))))))
612 (defun elpher-visit-previous-page ()
613 "Visit the previous page in the history."
615 (elpher-visit-page (pop elpher-history) nil t)
616 (error "No previous page")))
618 (defun elpher-reload-current-page ()
619 "Reload the current page, discarding any existing cached content."
620 (elpher-cache-content (elpher-page-address elpher-current-page) nil)
621 (elpher-visit-page elpher-current-page))
623 (defun elpher-save-pos ()
624 "Save the current position of point to the current page."
625 (when elpher-current-page
626 (elpher-cache-pos (elpher-page-address elpher-current-page) (point))))
628 (defun elpher-restore-pos ()
629 "Restore the position of point to that cached in the current page."
630 (let ((pos (elpher-get-cached-pos (elpher-page-address elpher-current-page))))
633 (goto-char (point-min)))))
635 (defun elpher-get-default-url-scheme ()
636 "Suggest default URL scheme for visiting addresses based on the current page."
637 (if elpher-current-page
638 (let* ((address (elpher-page-address elpher-current-page))
639 (current-type (elpher-address-type address)))
641 ((or (and 'file (guard (not elpher-history)))
643 elpher-default-url-type)
645 (url-type address))))
646 elpher-default-url-type))
649 ;;; Buffer preparation
652 (defvar elpher-buffer-name "*elpher*"
653 "The default name of the Elpher buffer.")
655 (defun elpher-update-header ()
656 "If `elpher-use-header' is true, display current page info in window header."
657 (if (and elpher-use-header elpher-current-page)
658 (let* ((display-string (elpher-page-display-string elpher-current-page))
659 (sanitized-display-string (replace-regexp-in-string "%" "%%" display-string))
660 (address (elpher-page-address elpher-current-page))
661 (tls-string (if (and (not (elpher-address-about-p address))
662 (member (elpher-address-protocol address)
663 '("gophers" "gemini")))
666 (header (concat sanitized-display-string
667 (propertize tls-string 'face 'bold))))
668 (setq header-line-format header))))
670 (defmacro elpher-with-clean-buffer (&rest args)
671 "Evaluate ARGS with a clean *elpher* buffer as current."
672 (declare (debug (body))) ;; Allow edebug to step through body
673 `(with-current-buffer elpher-buffer-name
674 (unless (eq major-mode 'elpher-mode)
675 ;; avoid resetting buffer-local variables
677 (let ((inhibit-read-only t)
678 (ansi-color-context nil)) ;; clean ansi interpreter state (also next 2 lines)
679 (setq-local xterm-color--current-fg nil)
680 (setq-local xterm-color--current-bg nil)
681 (setq-local network-security-level
682 (default-value 'network-security-level))
684 (elpher-update-header)
687 (defun elpher-buffer-message (string &optional line)
688 "Replace first line in elpher buffer with STRING.
689 If LINE is non-nil, replace that line instead."
690 (with-current-buffer elpher-buffer-name
691 (let ((inhibit-read-only t))
692 (goto-char (point-min))
695 (let ((data (match-data)))
698 (re-search-forward "^.*$")
699 (replace-match string))
700 (set-match-data data))))))
706 (defvar elpher-user-coding-system nil
707 "User-specified coding system to use for decoding text responses.")
709 (defun elpher-decode (string)
710 "Decode STRING using autodetected or user-specified coding system."
711 (decode-coding-string string
712 (if elpher-user-coding-system
713 elpher-user-coding-system
714 (detect-coding-string string t))))
716 (defun elpher-preprocess-text-response (string)
717 "Preprocess text selector response contained in STRING.
718 This involes decoding the character representation, and clearing
719 away CRs and any terminating period."
720 (elpher-decode (replace-regexp-in-string "\n\\.\n$" "\n"
721 (replace-regexp-in-string "\r" "" string))))
725 (defconst elpher-url-regex
726 "\\([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_~?/@|#-]\\)?\\)?"
727 "Regexp used to locate and buttonify URLs in text files loaded by elpher.")
729 (defun elpher-buttonify-urls (string)
730 "Turn substrings which look like urls in STRING into clickable buttons."
733 (goto-char (point-min))
734 (while (re-search-forward elpher-url-regex nil t)
735 (let ((page (elpher-page-from-url (substring-no-properties (match-string 0)))))
736 (make-text-button (match-beginning 0)
739 'action #'elpher-click-link
741 'help-echo #'elpher--page-button-help
746 ;; ANSI colors or XTerm colors (application and filtering)
748 (or (require 'xterm-color nil t)
749 (require 'ansi-color))
751 (defalias 'elpher-color-filter-apply
752 (if (fboundp 'xterm-color-filter)
754 (let ((_xterm-color-render nil))
755 (xterm-color-filter s)))
756 #'ansi-color-filter-apply)
757 "A function to filter out ANSI escape sequences.")
759 (defalias 'elpher-color-apply
760 (if (fboundp 'xterm-color-filter)
763 "A function to apply ANSI escape sequences.")
765 (defun elpher-text-has-ansi-escapes-p (string)
766 "Return non-nil if STRING includes an ANSI escape code."
768 (string-match "\x1b\\[" string)))
771 ;; Processing text for display
773 (defun elpher-process-text-for-display (string)
774 "Perform any desired processing of STRING prior to display as text.
775 Currently includes buttonifying URLs and processing ANSI escape codes."
776 (elpher-buttonify-urls (if (elpher-text-has-ansi-escapes-p string)
777 (if elpher-filter-ansi-from-text
778 (elpher-color-filter-apply string)
779 (elpher-color-apply string))
783 ;;; General network communication
786 (defun elpher-network-error (address error)
787 "Display ERROR message following unsuccessful negotiation with ADDRESS.
788 ERROR can be either an error object or a string."
789 (elpher-with-clean-buffer
790 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
791 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
792 (if (stringp error) error (error-message-string error)) "\n"
793 (propertize "\n----------------\n\n" 'face 'error)
794 "Press 'u' to return to the previous page.")))
797 (defvar elpher-network-timer nil
798 "Timer used for network connections.")
800 (defvar elpher-use-tls nil
801 "If non-nil, use TLS to communicate with gopher servers.")
803 (defvar elpher-client-certificate nil
804 "If non-nil, contains details of client certificate to use for TLS connections.
805 See `elpher-generate-certificate' for further info.")
807 (defun elpher-process-cleanup ()
808 "Immediately shut down any extant elpher process and timers."
809 (let ((p (get-process "elpher-process")))
810 (if p (delete-process p)))
811 (if (timerp elpher-network-timer)
812 (cancel-timer elpher-network-timer)))
814 (defun elpher-make-network-timer (thunk)
815 "Create a timer to run the THUNK after `elpher-connection-timeout' seconds.
816 This is just a wraper around `run-at-time' which additionally sets the
817 buffer-local variable `elpher-network-timer' to allow
818 `elpher-process-cleanup' to also clear the timer."
819 (let ((timer (run-at-time elpher-connection-timeout nil thunk)))
820 (setq-local elpher-network-timer timer)
823 (defun elpher-get-host-response (address default-port query-string response-processor
824 &optional use-tls force-ipv4)
825 "Generic function for retrieving data from ADDRESS.
827 When ADDRESS lacks a specific port, DEFAULT-PORT is used instead.
828 QUERY-STRING is a string sent to the host specified by ADDRESS to
829 illicet a response. This response is passed as an argument to the
830 function RESPONSE-PROCESSOR.
832 If non-nil, USE-TLS specifies that the connection is to be made over
833 TLS. If set to gemini, the certificate verification will be disabled
834 unless `elpher-gemini-TLS-cert-checks' is non-nil.
836 If non-nil, FORCE-IPV4 causes the network connection to be made over
837 ipv4 only. (The default behaviour when this is not set depends on
838 the host operating system and the local network capabilities.)"
839 (if (and use-tls (not (gnutls-available-p)))
840 (error "Use of TLS requires Emacs to be compiled with GNU TLS support")
841 (unless (< (elpher-address-port address) 65536)
842 (error "Cannot establish network connection: port number > 65536"))
843 (when (and (eq use-tls 'gemini) (not elpher-gemini-TLS-cert-checks))
844 (setq-local network-security-level 'low)
845 (setq-local gnutls-verify-error nil))
847 (let* ((kill-buffer-query-functions nil)
848 (port (elpher-address-port address))
849 (host (elpher-address-host address))
850 (service (if (> port 0) port default-port))
851 (response-string-parts nil)
854 (socks (or elpher-socks-always (string-suffix-p ".onion" host)))
855 (gnutls-params (list :type 'gnutls-x509pki
858 (elpher-get-current-keylist address)))
859 (timer (elpher-make-network-timer
861 (elpher-process-cleanup)
863 ; Try again with IPv4
864 ((not (or elpher-ipv4-always force-ipv4 socks))
865 (message "Connection timed out. Retrying with IPv4.")
866 (elpher-get-host-response address default-port
871 (not (eq use-tls 'gemini))
872 (or elpher-auto-disengage-TLS
874 "TLS connetion failed. Disable TLS mode and retry? ")))
875 (setq elpher-use-tls nil)
876 (elpher-get-host-response address default-port
881 (elpher-network-error address "Connection time-out."))))))
883 (socks-open-network-stream "elpher-process" nil host service)
884 (make-network-process :name "elpher-process"
886 :family (and (or force-ipv4
894 (cons 'gnutls-x509pki
895 (apply #'gnutls-boot-parameters
897 (process-put proc 'elpher-buffer (current-buffer))
898 (setq elpher-network-timer timer)
899 (set-process-coding-system proc 'binary 'binary)
900 (set-process-query-on-exit-flag proc nil)
901 (elpher-buffer-message (concat "Connecting to " host "..."
902 " (press 'u' to abort)"))
903 (set-process-filter proc
904 (lambda (_proc string)
908 (setq bytes-received (+ bytes-received (length string)))
909 (let ((new-hkbytes-received (/ bytes-received 102400)))
910 (when (> new-hkbytes-received hkbytes-received)
911 (setq hkbytes-received new-hkbytes-received)
912 (elpher-buffer-message
914 (number-to-string (/ hkbytes-received 10.0))
917 (setq response-string-parts
918 (cons string response-string-parts))))
919 (set-process-sentinel proc
922 (cancel-timer timer))
923 (condition-case the-error
925 ((string-prefix-p "open" event) ; request URL
926 (elpher-buffer-message
927 (concat "Connected to " host ". Receiving data..."
928 " (press 'u' to abort)"))
929 (let ((inhibit-eol-conversion t))
930 (process-send-string proc query-string)))
931 ((string-prefix-p "deleted" event)) ; do nothing
932 ((and (not response-string-parts)
933 (not (or elpher-ipv4-always force-ipv4 socks)))
934 ; Try again with IPv4
935 (message "Connection failed. Retrying with IPv4.")
936 (elpher-get-host-response address default-port
940 (response-string-parts
941 (with-current-buffer (process-get proc 'elpher-buffer)
942 (elpher-with-clean-buffer
943 (insert "Data received. Rendering..."))
944 (funcall response-processor
945 (apply #'concat (reverse response-string-parts)))
946 (elpher-restore-pos)))
948 (error "No response from server")))
950 (elpher-network-error address the-error)))))
953 (apply #'gnutls-negotiate :process proc gnutls-params))
954 (funcall (process-sentinel proc) proc "open\n")))
956 (elpher-process-cleanup)
957 (error "Error initiating connection to server")))))
960 ;;; Client-side TLS Certificate Management
963 (defun elpher-generate-certificate (common-name key-file cert-file url-prefix
965 "Generate a key and a self-signed client TLS certificate using openssl.
967 The Common Name field of the certificate is set to COMMON-NAME. The
968 arguments KEY-FILE and CERT-FILE should contain the absolute paths of
969 the key and certificate files to write.
971 If TEMPORARY is non-nil, the certificate will be given an exporation
972 period of one day, and the key and certificate files will be deleted
973 when the certificate is no longer needed for the current session.
975 Otherwise, the certificate will be given a 100 year expiration period
976 and the files will not be deleted.
978 The function returns a list containing the URL-PREFIX of addresses
979 for which the certificate should be used in this session, the
980 temporary flag, and the key and cert file names in the form required
981 by `gnutls-boot-parameters`."
982 (let ((exp-key-file (expand-file-name key-file))
983 (exp-cert-file (expand-file-name cert-file)))
986 (call-process elpher-openssl-command nil nil nil
987 "req" "-x509" "-newkey" "rsa:2048"
988 "-days" (if temporary "1" "36500")
990 "-subj" (concat "/CN=" common-name)
991 "-keyout" exp-key-file
992 "-out" exp-cert-file)
993 (list url-prefix temporary exp-key-file exp-cert-file))
995 (message "Check that openssl is installed, or customize `elpher-openssl-command`.")
996 (error "Program 'openssl', required for certificate generation, not found")))))
998 (defun elpher-generate-throwaway-certificate (url-prefix)
999 "Generate and return details of a throwaway certificate.
1000 The key and certificate files will be deleted when they are no
1001 longer needed for this session.
1003 The certificate will be marked as applying to all addresses with URLs
1004 starting with URL-PREFIX."
1005 (let* ((file-base (make-temp-name "elpher"))
1006 (key-file (concat temporary-file-directory file-base ".key"))
1007 (cert-file (concat temporary-file-directory file-base ".crt")))
1008 (elpher-generate-certificate file-base key-file cert-file url-prefix t)))
1010 (defun elpher-generate-persistent-certificate (file-base common-name url-prefix)
1011 "Generate and return details of a persistent certificate.
1012 The argument FILE-BASE is used as the base for the key and certificate
1013 files, while COMMON-NAME specifies the common name field of the
1016 The key and certificate files are written to in `elpher-certificate-directory'.
1018 In this session, the certificate will remain active for all addresses
1019 having URLs starting with URL-PREFIX."
1020 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
1021 (cert-file (concat elpher-certificate-directory file-base ".crt")))
1022 (elpher-generate-certificate common-name key-file cert-file url-prefix)))
1024 (defun elpher-get-existing-certificate (file-base url-prefix)
1025 "Return a certificate object corresponding to an existing certificate.
1026 It is assumed that the key files FILE-BASE.key and FILE-BASE.crt exist in
1027 the directory `elpher-certificate-directory'.
1029 In this session, the certificate will remain active for all addresses
1030 having URLs starting with URL-PREFIX."
1031 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
1032 (cert-file (concat elpher-certificate-directory file-base ".crt")))
1035 (expand-file-name key-file)
1036 (expand-file-name cert-file))))
1038 (defun elpher-install-certificate (key-file-src cert-file-src file-base url-prefix)
1039 "Install a key+certificate file pair in `elpher-certificate-directory'.
1040 The strings KEY-FILE-SRC and CERT-FILE-SRC are the existing key and
1041 certificate files to install. The argument FILE-BASE is used as the
1042 base for the installed key and certificate files.
1044 In this session, the certificate will remain active for all addresses
1045 having URLs starting with URL-PREFIX."
1046 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
1047 (cert-file (concat elpher-certificate-directory file-base ".crt")))
1048 (if (or (file-exists-p key-file)
1049 (file-exists-p cert-file))
1050 (error "A certificate with base name %s is already installed" file-base))
1051 (unless (and (file-exists-p key-file-src)
1052 (file-exists-p cert-file-src))
1053 (error "Either of the key or certificate files do not exist"))
1054 (copy-file key-file-src key-file)
1055 (copy-file cert-file-src cert-file)
1058 (expand-file-name key-file)
1059 (expand-file-name cert-file))))
1061 (defun elpher-list-existing-certificates ()
1062 "Return a list of the persistent certificates in `elpher-certificate-directory'."
1063 (unless (file-directory-p elpher-certificate-directory)
1064 (make-directory elpher-certificate-directory))
1067 (file-name-sans-extension file))
1068 (directory-files elpher-certificate-directory nil "\\.key$")))
1070 (defun elpher-forget-current-certificate ()
1071 "Causes any current certificate to be forgotten.)
1072 In the case of throwaway certificates, the key and certificate files
1075 (when elpher-client-certificate
1076 (unless (and (called-interactively-p 'any)
1077 (not (y-or-n-p (concat "Really forget client certificate? "
1078 "(Throwaway certificates will be deleted.)"))))
1079 (when (cadr elpher-client-certificate)
1080 (delete-file (elt elpher-client-certificate 2))
1081 (delete-file (elt elpher-client-certificate 3)))
1082 (setq-local elpher-client-certificate nil)
1083 (if (called-interactively-p 'any)
1084 (message "Client certificate forgotten.")))))
1086 (defun elpher-get-current-keylist (address)
1087 "Retrieve the `gnutls-boot-parameters'-compatable keylist.
1089 This is obtained from the client certificate described by
1090 `elpher-current-certificate', if one is available and the
1091 URL prefix for that certificate matches ADDRESS.
1093 If `elpher-current-certificate' is non-nil, and its URL prefix doesn't
1094 match that of ADDRESS, the certificate is forgotten."
1095 (if elpher-client-certificate
1096 (if (string-prefix-p (car elpher-client-certificate)
1097 (elpher-address-to-url address))
1098 (list (cddr elpher-client-certificate))
1099 (elpher-forget-current-certificate)
1100 (message "Disabling client certificate for new host")
1105 ;;; Gopher selector retrieval
1108 (defun elpher-get-gopher-response (address renderer)
1109 "Get response string from gopher server at ADDRESS and render using RENDERER."
1110 (elpher-get-host-response address 70
1111 (concat (elpher-gopher-address-selector address) "\r\n")
1113 (or (string= (elpher-address-protocol address) "gophers")
1116 (defun elpher-get-gopher-page (renderer)
1117 "Getter function for gopher pages.
1118 The RENDERER procedure is used to display the contents of the page
1119 once they are retrieved from the gopher server."
1120 (let* ((address (elpher-page-address elpher-current-page))
1121 (content (elpher-get-cached-content address)))
1122 (if (and content (funcall renderer nil))
1123 (elpher-with-clean-buffer
1125 (elpher-restore-pos))
1126 (elpher-with-clean-buffer
1127 (insert "LOADING... (use 'u' to cancel)\n"))
1128 (condition-case the-error
1129 (elpher-get-gopher-response address renderer)
1131 (elpher-network-error address the-error))))))
1134 ;;; Gopher index rendering
1137 (defun elpher-insert-margin (&optional type-name)
1138 "Insert index margin, optionally containing the TYPE-NAME, into current buffer."
1141 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
1143 (propertize "[" 'face 'elpher-margin-brackets)
1144 (propertize type-name 'face 'elpher-margin-key)
1145 (propertize "]" 'face 'elpher-margin-brackets))))
1147 (insert (make-string elpher-margin-width ?\s))))
1149 (defun elpher--page-button-help (_window buffer pos)
1150 "Function called by Emacs to generate mouse-over text.
1151 The arguments specify the BUFFER and the POS within the buffer of the item
1152 for which help is required. The function returns the help to be
1153 displayed. The _WINDOW argument is currently unused."
1154 (with-current-buffer buffer
1155 (let ((button (button-at pos)))
1157 (let* ((page (button-get button 'elpher-page))
1158 (address (elpher-page-address page)))
1159 (format "mouse-1, RET: open '%s'" (elpher-address-to-url address)))))))
1161 (defun elpher-insert-index-record (display-string &optional address)
1162 "Function to insert an index record into the current buffer.
1163 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
1164 If ADDRESS is not supplied or nil the record is rendered as an
1165 'information' line."
1166 (let* ((type (if address (elpher-address-type address) nil))
1167 (type-map-entry (cdr (assoc type elpher-type-map))))
1169 (let* ((margin-code (elt type-map-entry 2))
1170 (face (elt type-map-entry 3))
1171 (filtered-display-string (elpher-color-filter-apply display-string))
1172 (page (elpher-make-page filtered-display-string address)))
1173 (elpher-insert-margin margin-code)
1174 (insert-text-button filtered-display-string
1177 'action #'elpher-click-link
1179 'help-echo #'elpher--page-button-help))
1181 ('nil ;; Information
1182 (elpher-insert-margin)
1183 (let ((propertized-display-string
1184 (propertize display-string 'face 'elpher-info)))
1185 (insert (elpher-process-text-for-display propertized-display-string))))
1186 (`(gopher ,selector-type) ;; Unknown
1187 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
1188 (insert (propertize display-string
1189 'face 'elpher-unknown)))))
1192 (defun elpher-click-link (button)
1193 "Function called when the gopher link BUTTON is activated."
1194 (let ((page (button-get button 'elpher-page)))
1195 (elpher-visit-page page)))
1197 (defun elpher-render-index (data &optional _mime-type-string)
1198 "Render DATA as an index. MIME-TYPE-STRING is unused."
1199 (elpher-with-clean-buffer
1202 (let ((data-processed (elpher-preprocess-text-response data)))
1203 (dolist (line (split-string data-processed "\n"))
1205 (unless (= (length line) 0)
1206 (let* ((type (elt line 0))
1207 (fields (split-string (substring line 1) "\t"))
1208 (display-string (elt fields 0))
1209 (selector (elt fields 1))
1210 (host (elt fields 2))
1211 (port (if (elt fields 3)
1212 (string-to-number (elt fields 3))
1214 (address (elpher-make-gopher-address type selector host port)))
1215 (elpher-insert-index-record display-string address))))))
1216 (elpher-cache-content (elpher-page-address elpher-current-page)
1220 ;;; Gopher text rendering
1223 (defun elpher-render-text (data &optional _mime-type-string)
1224 "Render DATA as text. MIME-TYPE-STRING is unused."
1225 (elpher-with-clean-buffer
1228 (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
1229 (elpher-cache-content
1230 (elpher-page-address elpher-current-page)
1237 (defun elpher-render-image (data &optional _mime-type-string)
1238 "Display DATA as image. MIME-TYPE-STRING is unused."
1241 (if (display-images-p)
1242 (let* ((image (create-image
1246 (error "Unsupported image format")
1247 (let ((window (get-buffer-window elpher-buffer-name)))
1249 (setf (image-property image :max-width) (window-body-width window t))
1250 (setf (image-property image :max-height) (window-body-height window t))))
1251 (elpher-with-clean-buffer
1252 (insert-image image)
1253 (elpher-restore-pos))))
1254 (elpher-render-download data))))
1257 ;;; Gopher search retrieval and rendering
1260 (defun elpher-get-gopher-query-page (renderer)
1261 "Getter for gopher addresses requiring input.
1262 The response is rendered using the rendering function RENDERER."
1263 (let* ((address (elpher-page-address elpher-current-page))
1264 (content (elpher-get-cached-content address))
1266 (if (and content (funcall renderer nil))
1267 (elpher-with-clean-buffer
1269 (elpher-restore-pos)
1270 (message "Displaying cached search results. Reload to perform a new search."))
1272 (let* ((query-string (read-string "Query: "))
1273 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
1274 (search-address (elpher-make-gopher-address ?1
1276 (elpher-address-host address)
1277 (elpher-address-port address)
1278 (equal (elpher-address-type address) "gophers"))))
1281 (elpher-with-clean-buffer
1282 (insert "LOADING RESULTS... (use 'u' to cancel)"))
1283 (elpher-get-gopher-response search-address renderer))
1285 (elpher-visit-previous-page))))))
1288 ;;; Raw server response rendering
1291 (defun elpher-render-raw (data &optional mime-type-string)
1292 "Display raw DATA in buffer. MIME-TYPE-STRING is also displayed if provided."
1295 (elpher-with-clean-buffer
1296 (when mime-type-string
1297 (insert "MIME type specified by server: '" mime-type-string "'\n"))
1299 (goto-char (point-min)))
1300 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
1303 ;;; File save "rendering"
1306 (defun elpher-render-download (data &optional _mime-type-string)
1307 "Save DATA to file. MIME-TYPE-STRING is unused."
1310 (let* ((address (elpher-page-address elpher-current-page))
1311 (selector (if (elpher-address-gopher-p address)
1312 (elpher-gopher-address-selector address)
1313 (elpher-address-filename address))))
1314 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1315 (let* ((filename-proposal (file-name-nondirectory selector))
1316 (filename (read-file-name "Download complete. Save file as: "
1318 (if (> (length filename-proposal) 0)
1321 (let ((coding-system-for-write 'binary))
1322 (with-temp-file filename
1324 (message (format "Saved to file %s." filename))))))
1330 (defun elpher-render-html (data &optional _mime-type-string)
1331 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
1332 (elpher-with-clean-buffer
1335 (let ((dom (with-temp-buffer
1337 (libxml-parse-html-region (point-min) (point-max)))))
1338 (shr-insert-document dom)))))
1341 ;;; Gemini page retrieval
1344 (defvar elpher-gemini-redirect-chain)
1346 (defun elpher-get-gemini-response (address renderer)
1347 "Get response string from gemini server at ADDRESS and render using RENDERER."
1348 (elpher-get-host-response address 1965
1349 (concat (elpher-address-to-url address) "\r\n")
1350 (lambda (response-string)
1351 (elpher-process-gemini-response response-string renderer))
1354 (defun elpher-parse-gemini-response (response)
1355 "Parse the RESPONSE string and return a list of components.
1356 The list is of the form (code meta body). A response of nil implies
1357 that the response was malformed."
1358 (let ((header-end-idx (string-match "\r\n" response)))
1360 (let ((header (string-trim (substring response 0 header-end-idx)))
1361 (body (substring response (+ header-end-idx 2))))
1362 (if (>= (length header) 2)
1363 (let ((code (substring header 0 2))
1364 (meta (string-trim (substring header 2))))
1365 (list code meta body))
1366 (error "Malformed response: No response status found in header %s" header)))
1367 (error "Malformed response: No CRLF-delimited header found in response %s" response))))
1369 (defun elpher-process-gemini-response (response-string renderer)
1370 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
1371 (let ((response-components (elpher-parse-gemini-response response-string)))
1372 (let ((response-code (elt response-components 0))
1373 (response-meta (elt response-components 1))
1374 (response-body (elt response-components 2)))
1375 (pcase (elt response-code 0)
1376 (?1 ; Input required
1377 (elpher-with-clean-buffer
1378 (insert "Gemini server is requesting input."))
1379 (let* ((query-string
1381 (if (eq (elt response-code 1) ?1)
1382 (read-passwd (concat response-meta ": "))
1383 (read-string (concat response-meta ": ")))))
1384 (query-address (seq-copy (elpher-page-address elpher-current-page)))
1385 (old-fname (url-filename query-address)))
1386 (if (not query-string)
1387 (elpher-visit-previous-page)
1388 (setf (url-filename query-address)
1389 (concat old-fname "?" (url-build-query-string `((,query-string)))))
1390 (elpher-get-gemini-response query-address renderer))))
1391 (?2 ; Normal response
1392 (funcall renderer response-body response-meta))
1394 (message "Following redirect to %s" response-meta)
1395 (if (>= (length elpher-gemini-redirect-chain) 5)
1396 (error "More than 5 consecutive redirects followed"))
1397 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
1398 (if (member redirect-address elpher-gemini-redirect-chain)
1399 (error "Redirect loop detected"))
1400 (if (not (eq (elpher-address-type redirect-address) 'gemini))
1401 (error "Server tried to automatically redirect to non-gemini URL: %s"
1403 (elpher-page-set-address elpher-current-page redirect-address)
1404 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
1405 (elpher-get-gemini-response redirect-address renderer)))
1406 (?4 ; Temporary failure
1407 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
1408 response-code response-meta))
1409 (?5 ; Permanent failure
1410 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
1411 response-code response-meta))
1412 (?6 ; Client certificate required
1413 (elpher-with-clean-buffer
1414 (if elpher-client-certificate
1415 (insert "Gemini server does not recognise the provided TLS certificate:\n\n")
1416 (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
1418 (elpher-gemini-insert-text response-meta))
1419 (let ((chosen-certificate
1421 (elpher-acquire-client-certificate))))
1422 (unless chosen-certificate
1423 (error "Gemini server requires a client certificate and none was provided"))
1424 (setq-local elpher-client-certificate chosen-certificate))
1425 (elpher-with-clean-buffer)
1426 (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer))
1428 (error "Gemini server response unknown: %s %s"
1429 response-code response-meta))))))
1431 (defun elpher-acquire-client-certificate ()
1432 "Select and activate a pre-defined client certificate or prompt for one.
1433 In this case, \"pre-defined\" means a certificate provided by
1434 the `elpher-certificate-map' variable."
1435 (let* ((current-url (elpher-address-to-url (elpher-page-address elpher-current-page)))
1436 (entry (assoc current-url
1437 elpher-certificate-map
1438 #'string-prefix-p)))
1440 (let ((cert-url-regex (car entry))
1441 (cert-name (cadr entry)))
1442 (message "Using certificate \"%s\" specified in elpher-certificate-map with prefix \"%s\""
1443 cert-name cert-url-regex)
1444 (elpher-get-existing-certificate cert-name cert-url-regex))
1445 (elpher-prompt-for-client-certificate current-url))))
1447 (defun elpher--read-answer-polyfill (question answers)
1448 "Polyfill for `read-answer' in Emacs 26.1.
1449 QUESTION is a string containing a question, and ANSWERS
1450 is a list of possible answers, or an alist whose keys
1451 are the possible answers."
1452 (completing-read question answers))
1454 (if (fboundp 'read-answer)
1455 (defalias 'elpher-read-answer 'read-answer)
1456 (defalias 'elpher-read-answer 'elpher--read-answer-polyfill))
1460 (defun elpher-prompt-for-client-certificate (url-prefix)
1461 "Prompt for a client certificate to use to establish a TLS connection.
1463 In this session, the chosen certificate will remain active for all
1464 addresses with URLs matching URL-PREFIX."
1465 (let* ((read-answer-short t))
1466 (pcase (read-answer "What do you want to do? "
1468 "generate and use throw-away certificate")
1470 "generate new or use existing persistent certificate")
1472 "stop immediately")))
1474 (setq-local elpher-client-certificate (elpher-generate-throwaway-certificate url-prefix)))
1476 (let* ((existing-certificates (elpher-list-existing-certificates))
1477 (file-base (completing-read
1478 "Nickname for new or existing certificate (autocompletes, empty response aborts): "
1479 existing-certificates)))
1480 (if (string-empty-p (string-trim file-base))
1482 (if (member file-base existing-certificates)
1483 (setq-local elpher-client-certificate
1484 (elpher-get-existing-certificate file-base url-prefix))
1485 (pcase (read-answer "Generate new certificate or install externally-generated one? "
1487 "generate new certificate")
1489 "install existing certificate")
1491 "stop immediately")))
1493 (let ((common-name (read-string "Common Name field for new certificate: "
1495 (message "New key and self-signed certificate written to %s"
1496 elpher-certificate-directory)
1497 (elpher-generate-persistent-certificate file-base
1501 (let* ((cert-file (read-file-name "Certificate file: " nil nil t))
1502 (key-file (read-file-name "Key file: " nil nil t)))
1503 (message "Key and certificate installed in %s for future use"
1504 elpher-certificate-directory)
1505 (elpher-install-certificate key-file cert-file file-base
1510 (defun elpher-get-gemini-page (renderer)
1511 "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
1512 (let* ((address (elpher-page-address elpher-current-page))
1513 (content (elpher-get-cached-content address)))
1514 (condition-case the-error
1515 (if (and content (funcall renderer nil))
1516 (elpher-with-clean-buffer
1518 (elpher-restore-pos))
1519 (elpher-with-clean-buffer
1520 (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
1521 (setq elpher-gemini-redirect-chain nil)
1522 (elpher-get-gemini-response address renderer))
1524 (elpher-network-error address the-error)))))
1526 ;;; Gemini page rendering
1529 (defun elpher-render-gemini (body &optional mime-type-string)
1530 "Render gemini response BODY with rendering MIME-TYPE-STRING."
1533 (let* ((mime-type-string* (if (or (not mime-type-string)
1534 (string-empty-p mime-type-string))
1535 "text/gemini; charset=utf-8"
1537 (mime-type-split (split-string mime-type-string* ";" t))
1538 (mime-type (string-trim (car mime-type-split)))
1539 (parameters (mapcar (lambda (s)
1540 (let ((key-val (split-string s "=")))
1541 (list (downcase (string-trim (car key-val)))
1542 (downcase (string-trim (cadr key-val))))))
1543 (cdr mime-type-split))))
1544 (when (string-prefix-p "text/" mime-type)
1545 (setq body (decode-coding-string
1547 (if (assoc "charset" parameters)
1548 (intern (cadr (assoc "charset" parameters)))
1550 (setq body (replace-regexp-in-string "\r" "" body)))
1552 ((or "text/gemini" "")
1553 (elpher-render-gemini-map body parameters))
1555 (elpher-render-html body))
1556 ((pred (string-prefix-p "text/"))
1557 (elpher-render-gemini-plain-text body parameters))
1558 ((pred (string-prefix-p "image/"))
1559 (elpher-render-image body))
1561 (elpher-render-download body))))))
1563 (defun elpher-gemini-get-link-url (link-line)
1564 "Extract the url portion of LINK-LINE, a gemini map file link line.
1565 Returns nil in the event that the contents of the line following the
1566 => prefix are empty."
1567 (let ((l (split-string (substring link-line 2))))
1569 (string-trim (elt l 0))
1572 (defun elpher-gemini-get-link-display-string (link-line)
1573 "Extract the display string portion of LINK-LINE, a gemini map file link line.
1574 Return nil if this portion is not provided."
1575 (let* ((rest (string-trim (elt (split-string link-line "=>") 1)))
1576 (idx (string-match "[ \t]" rest)))
1578 (elpher-color-filter-apply (string-trim (substring rest (+ idx 1)))))))
1580 (defun elpher-collapse-dot-sequences (filename)
1581 "Collapse dot sequences in the (absolute) FILENAME.
1582 For instance, the filename \"/a/b/../c/./d\" will reduce to \"/a/c/d\""
1583 (let* ((path (split-string filename "/" t))
1584 (is-directory (string-match-p (rx (: (or "." ".." "/") line-end)) filename))
1585 (path-reversed-normalized
1586 (seq-reduce (lambda (a b)
1587 (cond ((equal b "..") (cdr a))
1591 (path-normalized (reverse path-reversed-normalized)))
1593 (concat "/" (string-join path-normalized "/") (and is-directory "/"))
1596 (defun elpher-address-from-gemini-url (url)
1597 "Extract address from URL with defaults as per gemini map files.
1598 While there's obviously some redundancy here between this function and
1599 `elpher-address-from-url', gemini map file URLs require enough special
1600 treatment that a separate function is warranted."
1601 (let ((address (url-generic-parse-url url))
1602 (current-address (elpher-page-address elpher-current-page)))
1603 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
1604 (if (url-host address) ;if there is an explicit host, filenames are absolute
1605 (if (string-empty-p (url-filename address))
1606 (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
1607 (setf (url-host address) (url-host current-address))
1608 (setf (url-fullness address) (url-host address)) ; set fullness to t if host is set
1609 (setf (url-portspec address) (url-portspec current-address)) ; (url-port) too slow!
1610 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
1611 (setf (url-filename address)
1612 (concat (file-name-directory (url-filename current-address))
1613 (url-filename address)))))
1614 (when (url-host address)
1615 (setf (url-host address) (puny-encode-domain (url-host address))))
1616 (unless (url-type address)
1617 (setf (url-type address) (url-type current-address)))
1618 (when (equal (url-type address) "gemini")
1619 (setf (url-filename address)
1620 (elpher-collapse-dot-sequences (url-filename address)))))
1621 (elpher-remove-redundant-ports address)))
1623 (defun elpher-gemini-insert-link (link-line)
1624 "Insert link described by LINK-LINE into a text/gemini document."
1625 (let ((url (elpher-gemini-get-link-url link-line)))
1627 (let* ((given-display-string (elpher-gemini-get-link-display-string link-line))
1628 (address (elpher-address-from-gemini-url url))
1629 (type (if address (elpher-address-type address) nil))
1630 (type-map-entry (cdr (assoc type elpher-type-map)))
1631 (fill-prefix (make-string (+ 1 (length elpher-gemini-link-string)) ?\s)))
1632 (when type-map-entry
1633 (insert elpher-gemini-link-string)
1634 (let* ((face (elt type-map-entry 3))
1635 (display-string (or given-display-string
1636 (elpher-address-to-iri address)))
1637 (page (elpher-make-page display-string
1639 (insert-text-button display-string
1642 'action #'elpher-click-link
1644 'help-echo #'elpher--page-button-help))
1647 (defun elpher-gemini-insert-header (header-line)
1648 "Insert header described by HEADER-LINE into a text/gemini document.
1649 The gemini map file line describing the header is given
1651 (when (string-match "^\\(#+\\)[ \t]*" header-line)
1652 (let* ((level (length (match-string 1 header-line)))
1653 (header (substring header-line (match-end 0)))
1655 (1 'elpher-gemini-heading1)
1656 (2 'elpher-gemini-heading2)
1657 (3 'elpher-gemini-heading3)
1659 (fill-column (if (display-graphic-p)
1661 (font-get (font-spec :name (face-font 'default)) :size))
1662 (font-get (font-spec :name (face-font face)) :size)) fill-column)))
1663 (unless (display-graphic-p)
1664 (insert (make-string level ?#) " "))
1665 (insert (propertize header
1671 (defun elpher-gemini-insert-text (text-line)
1672 "Insert a plain non-preformatted TEXT-LINE into a text/gemini document.
1673 This function uses Emacs' auto-fill to wrap text sensibly to a maximum
1674 width defined by `elpher-gemini-max-fill-width'."
1678 (group (or (: "*" (+ (any " \t")))
1679 (: ">" (* (any " \t"))))))))
1681 (let* ((line-prefix (match-string 1 text-line))
1682 (processed-text-line
1684 (cond ((string-prefix-p "*" line-prefix)
1686 (replace-regexp-in-string "\\*"
1687 elpher-gemini-bullet-string
1688 (match-string 0 text-line))
1689 (substring text-line (match-end 0))))
1690 ((string-prefix-p ">" line-prefix)
1691 (propertize text-line 'face 'elpher-gemini-quoted))
1694 (fill-prefix (if line-prefix
1695 (make-string (length (match-string 0 text-line)) ?\s)
1697 (insert (elpher-process-text-for-display processed-text-line))
1700 (defun elpher-gemini-pref-expand-collapse (button)
1701 "Function called when the preformatted text toggle BUTTON is activated."
1702 (let ((id (button-get button 'pref-id)))
1703 (if (invisible-p id)
1704 (remove-from-invisibility-spec id)
1705 (add-to-invisibility-spec id))
1708 (defun elpher-gemini-insert-preformatted-toggler (alt-text)
1709 "Insert a button for toggling the visibility of preformatted text.
1710 If non-nil, ALT-TEXT is displayed alongside the button."
1711 (let* ((url-string (url-recreate-url (elpher-page-address elpher-current-page)))
1712 (pref-id (intern (concat "pref-"
1713 (number-to-string (point))
1716 (insert elpher-gemini-preformatted-toggle-bullet)
1718 (insert (propertize (concat alt-text " ")
1719 'face 'elpher-gemin-preformatted)))
1720 (insert-text-button elpher-gemini-preformatted-toggle-label
1721 'action #'elpher-gemini-pref-expand-collapse
1723 'face 'elpher-gemini-preformatted-toggle)
1724 (add-to-invisibility-spec pref-id)
1728 (defun elpher-gemini-insert-preformatted-line (line &optional pref-id)
1729 "Insert a LINE of preformatted text.
1730 PREF-ID is the value assigned to the \"invisible\" text attribute, which
1731 can be used to toggle the display of the preformatted text."
1732 (insert (propertize (concat (elpher-process-text-for-display
1733 (propertize line 'face 'elpher-gemini-preformatted))
1736 'rear-nonsticky t)))
1738 (defun elpher-render-gemini-map (data _parameters)
1739 "Render DATA as a gemini map file, PARAMETERS is currently unused."
1740 (elpher-with-clean-buffer
1742 (setq-local buffer-invisibility-spec nil)
1743 (let ((preformatted nil)
1744 (adaptive-fill-mode nil)) ;Prevent automatic setting of fill-prefix
1745 (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))
1746 (dolist (line (split-string data "\n"))
1748 ((rx (: string-start "```" (opt (let alt-text (+ any)))))
1752 (if elpher-gemini-hide-preformatted
1753 (elpher-gemini-insert-preformatted-toggler alt-text)
1755 ((guard preformatted)
1756 (elpher-gemini-insert-preformatted-line line preformatted))
1757 ((pred (string-prefix-p "=>"))
1758 (elpher-gemini-insert-link line))
1759 ((pred (string-prefix-p "#"))
1760 (elpher-gemini-insert-header line))
1761 (_ (elpher-gemini-insert-text line))))
1762 (elpher-cache-content
1763 (elpher-page-address elpher-current-page)
1766 (defun elpher-render-gemini-plain-text (data _parameters)
1767 "Render DATA as plain text file. PARAMETERS is currently unused."
1768 (elpher-with-clean-buffer
1769 (insert (elpher-process-text-for-display data))
1770 (elpher-cache-content
1771 (elpher-page-address elpher-current-page)
1774 (defun elpher-build-current-imenu-index ()
1775 "Build imenu index for current elpher buffer."
1777 (goto-char (point-min))
1780 (while (setq match (text-property-search-forward 'gemini-heading t t))
1782 (buffer-substring-no-properties (prop-match-beginning match)
1783 (prop-match-end match))
1784 (prop-match-beginning match))
1786 (reverse headers))))
1789 ;;; Finger page connection
1792 (defun elpher-get-finger-page (renderer)
1793 "Opens a finger connection to the current page address.
1794 The result is rendered using RENDERER."
1795 (let* ((address (elpher-page-address elpher-current-page))
1796 (content (elpher-get-cached-content address)))
1797 (if (and content (funcall renderer nil))
1798 (elpher-with-clean-buffer
1800 (elpher-restore-pos))
1801 (elpher-with-clean-buffer
1802 (insert "LOADING... (use 'u' to cancel)\n"))
1803 (condition-case the-error
1804 (let* ((kill-buffer-query-functions nil)
1805 (user (let ((filename (elpher-address-filename address)))
1806 (if (> (length filename) 1)
1807 (substring filename 1)
1808 (elpher-address-user address)))))
1809 (elpher-get-host-response address 79
1810 (concat user "\r\n")
1813 (elpher-network-error address the-error))))))
1816 ;;; Telnet page connection
1819 (defun elpher-get-telnet-page (renderer)
1820 "Opens a telnet connection to the current page address (RENDERER must be nil)."
1822 (elpher-visit-previous-page)
1823 (error "Command not supported for telnet URLs"))
1824 (let* ((address (elpher-page-address elpher-current-page))
1825 (host (elpher-address-host address))
1826 (port (elpher-address-port address)))
1827 (elpher-visit-previous-page)
1833 ;;; Other URL page opening
1836 (defun elpher-get-other-url-page (renderer)
1837 "Getter which attempts to open the URL specified by the current page.
1838 The RENDERER argument to this getter must be nil."
1840 (elpher-visit-previous-page)
1841 (error "Command not supported for general URLs"))
1842 (let* ((address (elpher-page-address elpher-current-page))
1843 (url (elpher-address-to-url address)))
1844 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1845 (message "Opening URL...")
1846 (if elpher-open-urls-with-eww
1854 (defun elpher-get-file-page (renderer)
1855 "Getter which renders a local file using RENDERER.
1856 Assumes UTF-8 encoding for all text files."
1857 (let* ((address (elpher-page-address elpher-current-page))
1858 (filename (elpher-address-filename address)))
1859 (unless (file-exists-p filename)
1860 (elpher-visit-previous-page)
1861 (error "File not found"))
1862 (unless (file-readable-p filename)
1863 (elpher-visit-previous-page)
1864 (error "Could not read from file"))
1865 (let ((body (with-temp-buffer
1866 (let ((coding-system-for-read 'binary)
1867 (coding-system-for-write 'binary))
1868 (insert-file-contents-literally filename)
1869 (encode-coding-string (buffer-string) 'raw-text)))))
1871 (funcall renderer body nil)
1872 (pcase (file-name-extension filename)
1873 ((or "gmi" "gemini")
1874 (elpher-render-gemini-map (decode-coding-string body 'utf-8) nil))
1876 (elpher-render-html (decode-coding-string body 'utf-8)))
1878 (elpher-render-text (decode-coding-string body 'utf-8)))
1879 ((or "jpg" "jpeg" "gif" "png" "bmp" "tif" "tiff")
1880 (elpher-render-image body))
1881 ((or "gopher" "gophermap")
1882 (elpher-render-index (elpher-decode body)))
1884 (elpher-render-download body))))
1885 (elpher-restore-pos))))
1888 ;;; Welcome page retrieval
1891 (defun elpher-get-welcome-page (renderer)
1892 "Getter which displays the welcome page (RENDERER must be nil)."
1894 (elpher-visit-previous-page)
1895 (error "Command not supported for welcome page"))
1896 (elpher-with-clean-buffer
1897 (insert " --------------------------------------------\n"
1898 " Elpher Gopher and Gemini Client \n"
1899 " version " elpher-version "\n"
1900 " --------------------------------------------\n"
1902 "Default bindings:\n"
1904 " - TAB/Shift-TAB: next/prev item on current page\n"
1905 " - RET/mouse-1: open item under cursor\n"
1906 " - m: select an item on current page by name (autocompletes)\n"
1907 " - u/mouse-3/U: return to previous page or to the start page\n"
1908 " - g: go to a particular address (gopher, gemini, finger)\n"
1909 " - o/O: open a different address selector or the root menu of the current server\n"
1910 " - d/D: download item under cursor or current page\n"
1911 " - i/I: info on item under cursor or current page\n"
1912 " - c/C: copy URL representation of item under cursor or current page\n"
1913 " - a/A: bookmark the item under cursor or current page\n"
1914 " - B: list all bookmarks\n"
1915 " - s/S: show current history stack or all previously visted pages\n"
1916 " - r: redraw current page (using cached contents if available)\n"
1917 " - R: reload current page (regenerates cache)\n"
1918 " - !: set character coding system for gopher (default is to autodetect)\n"
1919 " - T: toggle TLS gopher mode\n"
1920 " - F: forget/discard current TLS client certificate\n"
1921 " - .: display the raw server response for the current page\n"
1923 "Start your exploration of gopher space and gemini:\n")
1924 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1925 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1926 (elpher-insert-index-record "Project Gemini home page"
1927 (elpher-address-from-url "gemini://gemini.circumlunar.space/"))
1929 "Alternatively, select a search engine and enter some search terms:\n")
1930 (elpher-insert-index-record "Gopher Search Engine (Veronica-2)"
1931 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1932 (elpher-insert-index-record "Gemini Search Engine (geminispace.info)"
1933 (elpher-address-from-url "gemini://geminispace.info/search"))
1935 "Your bookmarks are stored in your ")
1936 (insert-text-button "bookmark list"
1938 'action #'elpher-click-link
1940 'help-echo #'elpher--page-button-help
1942 (elpher-make-page "Elpher Bookmarks"
1943 (elpher-make-about-address 'bookmarks)))
1946 "(Bookmarks from legacy elpher-bookmarks files will be automatically imported.)\n"
1949 "The gopher home of the Elpher project is here:\n")
1950 (elpher-insert-index-record "The Elpher Project Page"
1951 (elpher-make-gopher-address ?1
1955 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1957 "The following info documentation is available:\n"
1959 (insert-text-button "Elpher Manual"
1965 'help-echo help-string)
1967 (insert-text-button "Changes introduced by the latest release"
1971 (info "(elpher)News"))
1973 'help-echo help-string))
1976 (concat "(These documents should be available if you have installed Elpher\n"
1977 " from MELPA or non-GNU ELPA. Otherwise you may have to install the\n"
1978 " manual yourself.)\n")
1980 (elpher-restore-pos)))
1983 ;;; History page retrieval
1986 (defun elpher-show-history ()
1987 "Show the current contents of elpher's history stack.
1988 Use \\[elpher-show-visited-pages] to see the entire history.
1989 This is rendered using `elpher-get-history-page' via `elpher-type-map'."
1992 (elpher-make-page "Current History Stack"
1993 (elpher-make-about-address 'history))))
1995 (defun elpher-show-visited-pages ()
1996 "Show the all the pages you've visited using Elpher.
1997 Use \\[elpher-show-history] to see just the current history stack.
1998 This is rendered using `elpher-get-visited-pages-page' via `elpher-type-map'."
2001 (elpher-make-page "Elpher Visted Pages"
2002 (elpher-make-about-address 'visited-pages))))
2004 (defun elpher-get-history-page (renderer)
2005 "Getter which displays the history page (RENDERER must be nil)."
2007 (elpher-visit-previous-page)
2008 (error "Command not supported for history page"))
2009 (elpher-display-history-links elpher-history "Current history stack"))
2011 (defun elpher-get-visited-pages-page (renderer)
2012 "Getter which displays the list of visited pages (RENDERER must be nil)."
2014 (elpher-visit-previous-page)
2015 (error "Command not supported for history page"))
2016 (elpher-display-history-links
2017 (seq-filter (lambda (page)
2018 (not (elpher-address-about-p (elpher-page-address page))))
2019 elpher-visited-pages)
2020 "All visited pages"))
2022 (defun elpher-display-history-links (pages title)
2023 "Show all PAGES in an Elpher buffer with a given TITLE."
2024 (let* ((title-line (concat " ---- " title " ----"))
2025 (footer-line (make-string (length title-line) ?-)))
2026 (elpher-with-clean-buffer
2027 (insert title-line "\n\n")
2029 (dolist (page pages)
2031 (let ((display-string (elpher-page-display-string page))
2032 (address (elpher-page-address page)))
2033 (elpher-insert-index-record display-string address))))
2034 (insert "No history items found.\n"))
2035 (insert "\n " footer-line "\n"
2036 "Select an entry or press 'u' to return to the previous page.")
2037 (elpher-restore-pos))))
2043 ;; This code allows Elpher to use the standard Emacs bookmarks: `C-x r
2044 ;; m' to add a bookmark, `C-x r l' to list bookmarks (which is where
2045 ;; you can anotate bookmarks!), `C-x r b' to jump to a bookmark, and
2046 ;; so on. See the Bookmarks section in the Emacs info manual for more.
2048 (defvar elpher-bookmark-link nil
2049 "Prefer bookmarking a link or the current page.
2050 Bind this variable dynamically, or set it to t.
2051 If you set it to t, the commands \\[bookmark-set-no-overwrite]
2052 and \\[elpher-set-bookmark-no-overwrite] do the same thing.")
2054 (defun elpher-bookmark-make-record ()
2055 "Return a bookmark record.
2056 If `elpher-bookmark-link' is non-nil and point is on a link button,
2057 return a bookmark record for that link. Otherwise, return a bookmark
2058 record for the current elpher page."
2059 (let* ((button (and elpher-bookmark-link (button-at (point))))
2061 (button-get button 'elpher-page)
2062 elpher-current-page)))
2064 (error "Cannot bookmark this link"))
2065 (let* ((address (elpher-page-address page))
2066 (url (elpher-address-to-url address))
2067 (display-string (elpher-page-display-string page))
2068 (pos (if button nil (point))))
2069 (if (elpher-address-about-p address)
2070 (error "Cannot bookmark %s" display-string)
2072 (defaults . (,display-string))
2075 (handler . elpher-bookmark-jump))))))
2078 (defun elpher-bookmark-jump (bookmark)
2079 "Handler used to open a bookmark using elpher.
2080 The argument BOOKMARK is a bookmark record passed to the function.
2081 This handler is responsible for loading the bookmark in some buffer,
2082 then making that buffer the current buffer. It should not switch
2084 (let* ((url (cdr (assq 'location bookmark)))
2085 (cleaned-url (string-trim url))
2086 (page (elpher-page-from-url cleaned-url))
2087 (buffer (get-buffer-create elpher-buffer-name)))
2088 (elpher-with-clean-buffer
2089 (elpher-visit-page page))
2093 (defun elpher-bookmark-link ()
2094 "Bookmark the link at point.
2095 To bookmark the current page, use \\[elpher-bookmark-current]."
2097 (let ((elpher-bookmark-link t))
2098 (bookmark-set-no-overwrite)))
2100 (defun elpher-bookmark-current ()
2101 "Bookmark the current page.
2102 To bookmark the link at point use \\[elpher-bookmark-link]."
2104 (call-interactively #'bookmark-set-no-overwrite))
2106 (defun elpher-bookmark-import (file)
2107 "Import legacy Elpher bookmarks file FILE into Emacs bookmarks."
2108 (interactive (list (if (and (boundp 'elpher-bookmarks-file)
2109 (file-readable-p elpher-bookmarks-file))
2110 elpher-bookmarks-file
2111 (read-file-name "Old Elpher bookmarks: "
2112 user-emacs-directory nil t
2113 "elpher-bookmarks"))))
2114 (dolist (bookmark (with-temp-buffer
2115 (insert-file-contents file)
2116 (read (current-buffer))))
2117 (let* ((display-string (car bookmark))
2118 (url (cadr bookmark))
2119 (record `(,display-string
2121 (handler . elpher-bookmark-jump))))
2122 (bookmark-store display-string (cdr record) t)))
2125 (defun elpher-get-bookmarks-page (renderer)
2126 "Getter which displays the bookmarks (RENDERER must be nil)."
2128 (elpher-visit-previous-page)
2129 (error "Command not supported for bookmarks page"))
2131 (let ((old-bookmarks-file (or (and (boundp 'elpher-bookmarks-file)
2132 elpher-bookmarks-file)
2133 (locate-user-emacs-file "elpher-bookmarks"))))
2134 (when (and (file-readable-p old-bookmarks-file)
2135 (y-or-n-p (concat "Legacy elpher-bookmarks file \""
2137 "\" found. Import now?")))
2138 (elpher-bookmark-import old-bookmarks-file)
2139 (rename-file old-bookmarks-file (concat old-bookmarks-file "-legacy"))))
2141 (if (and elpher-use-emacs-bookmark-menu
2144 (elpher-visit-previous-page)
2145 (call-interactively #'bookmark-bmenu-list))
2146 (elpher-with-clean-buffer
2147 (insert " ---- Elpher Bookmarks ---- \n\n")
2148 (bookmark-maybe-load-default-file)
2149 (dolist (bookmark (bookmark-maybe-sort-alist))
2150 (when (eq #'elpher-bookmark-jump (alist-get 'handler (cdr bookmark)))
2151 (let* ((name (car bookmark))
2152 (url (alist-get 'location (cdr bookmark)))
2153 (address (elpher-address-from-url url)))
2154 (elpher-insert-index-record name address))))
2155 (when (<= (line-number-at-pos) 3)
2156 (insert "No bookmarked pages found.\n"))
2157 (insert "\n --------------------------\n\n"
2158 "Select an entry or press 'u' to return to the previous page.\n\n"
2159 "Bookmarks can be renamed or deleted via the ")
2160 (insert-text-button "Emacs bookmark menu"
2163 (call-interactively #'bookmark-bmenu-list))
2165 'help-echo "RET,mouse-1: open Emacs bookmark menu")
2166 (insert (substitute-command-keys
2167 ",\nwhich can also be opened from anywhere using '\\[bookmark-bmenu-list]'."))
2168 (elpher-restore-pos))))
2170 (defun elpher-show-bookmarks ()
2171 "Interactive function to display the current list of elpher bookmarks."
2174 (elpher-make-page "Elpher Bookmarks"
2175 (elpher-make-about-address 'bookmarks))))
2183 (defun elpher-org-export-link (link description format protocol)
2184 "Export a LINK with DESCRIPTION for the given PROTOCOL and FORMAT.
2186 FORMAT is an Org export backend. DESCRIPTION may be nil. PROTOCOL may be one
2187 of gemini, gopher or finger."
2188 (let* ((url (if (equal protocol "elpher")
2189 (string-remove-prefix "elpher:" link)
2190 (format "%s:%s" protocol link)))
2191 (desc (or description url)))
2193 (`gemini (format "=> %s %s" url desc))
2194 (`html (format "<a href=\"%s\">%s</a>" url desc))
2195 (`latex (format "\\href{%s}{%s}" url desc))
2196 (_ (if (not description)
2198 (format "%s (%s)" desc url))))))
2200 (defun elpher-org-store-link ()
2201 "Store link to an `elpher' page in Org."
2202 (when (eq major-mode 'elpher-mode)
2203 (let* ((url (elpher-info-current))
2204 (desc (car elpher-current-page))
2206 ((string-prefix-p "gemini:" url) "gemini")
2207 ((string-prefix-p "gopher:" url) "gopher")
2208 ((string-prefix-p "finger:" url) "finger")
2210 (when (equal "elpher" protocol)
2211 ;; Weird link. Or special inner link?
2212 (setq url (concat "elpher:" url)))
2213 (org-link-store-props :type protocol :link url :description desc)
2216 (defun elpher-org-follow-link (link protocol)
2217 "Visit a LINK for the given PROTOCOL.
2219 PROTOCOL may be one of gemini, gopher or finger. This method also
2220 supports the old protocol elpher, where the link is self-contained."
2221 (let ((url (if (equal protocol "elpher")
2222 (string-remove-prefix "elpher:" link)
2223 (format "%s:%s" protocol link))))
2226 (defun elpher-org-mode-integration ()
2227 "Set up `elpher' integration for `org-mode'."
2228 (org-link-set-parameters
2230 :store #'elpher-org-store-link
2231 :export (lambda (link description format _plist)
2232 (elpher-org-export-link link description format "elpher"))
2233 :follow (lambda (link _arg) (elpher-org-follow-link link "elpher")))
2234 (org-link-set-parameters
2236 :export (lambda (link description format _plist)
2237 (elpher-org-export-link link description format "gemini"))
2238 :follow (lambda (link _arg) (elpher-org-follow-link link "gemini")))
2239 (org-link-set-parameters
2241 :export (lambda (link description format _plist)
2242 (elpher-org-export-link link description format "gopher"))
2243 :follow (lambda (link _arg) (elpher-org-follow-link link "gopher")))
2244 (org-link-set-parameters
2246 :export (lambda (link description format _plist)
2247 (elpher-org-export-link link description format "gophers"))
2248 :follow (lambda (link _arg) (elpher-org-follow-link link "gophers")))
2249 (org-link-set-parameters
2251 :export (lambda (link description format _plist)
2252 (elpher-org-export-link link description format "finger"))
2253 :follow (lambda (link _arg) (elpher-org-follow-link link "finger"))))
2255 (add-hook 'org-mode-hook #'elpher-org-mode-integration)
2260 (defun elpher-browse-url-elpher (url &rest _args)
2261 "Browse URL using Elpher. This function is used by `browse-url'."
2262 (interactive (browse-url-interactive-arg "Elpher URL: "))
2265 ;; Use elpher to open gopher, finger and gemini links
2266 ;; For recent version of `browse-url' package
2267 (if (boundp 'browse-url-default-handlers)
2269 'browse-url-default-handlers
2270 '("^\\(gopher\\|gophers\\|finger\\|gemini\\)://" . elpher-browse-url-elpher))
2271 ;; Patch `browse-url-browser-function' for older ones. The value of
2272 ;; that variable is `browse-url-default-browser' by default, so
2273 ;; that's the function that gets advised. If the value is an alist,
2274 ;; however, we don't know what to do. Better not interfere?
2275 (when (and (symbolp browse-url-browser-function)
2276 (fboundp browse-url-browser-function))
2277 (advice-add browse-url-browser-function :before-while
2278 (lambda (url &rest _args)
2279 "Handle gemini, gopher, and finger schemes using Elpher."
2280 (let ((scheme (downcase (car (split-string url ":" t)))))
2281 (if (member scheme '("gemini" "gopher" "gophers" "finger"))
2282 ;; `elpher-go' always returns nil, which will stop the
2283 ;; advice chain here in a before-while
2285 ;; chain must continue, then return t.
2288 ;; Register "gemini://" as a URI scheme so `browse-url' does the right thing
2289 (with-eval-after-load 'thingatpt
2290 (add-to-list 'thing-at-point-uri-schemes "gemini://"))
2294 ;; Make mu4e aware of the gemini world
2295 (setq mu4e~view-beginning-of-url-regexp
2296 "\\(?:https?\\|gopher\\|gophers\\|finger\\|gemini\\)://\\|mailto:")
2300 ;; Let elpher handle gemini, gopher links in eww buffer.
2301 (setq eww-use-browse-url
2302 "\\`mailto:\\|\\(\\`gemini\\|\\`gopher\\|\\`gophers\\|\\`finger\\)://")
2305 ;;; Interactive procedures
2308 (defun elpher-next-link ()
2309 "Move point to the next link on the current page."
2313 (defun elpher-prev-link ()
2314 "Move point to the previous link on the current page."
2316 (backward-button 1))
2318 (defun elpher-follow-current-link ()
2319 "Open the link or url at point."
2324 (defun elpher-go (host-or-url)
2325 "Go to a particular gopher site HOST-OR-URL.
2326 When run interactively HOST-OR-URL is read from the minibuffer."
2328 (read-string (format "Visit URL (default scheme %s): "
2329 (elpher-get-default-url-scheme)))))
2330 (let ((trimmed-host-or-url (string-trim host-or-url)))
2331 (unless (string-empty-p trimmed-host-or-url)
2332 (let ((page (elpher-page-from-url trimmed-host-or-url
2333 (elpher-get-default-url-scheme))))
2334 (unless (get-buffer-window elpher-buffer-name t)
2335 (switch-to-buffer elpher-buffer-name))
2336 (elpher-with-clean-buffer
2337 (elpher-visit-page page))
2338 nil)))) ; non-nil value is displayed by eshell
2340 (defun elpher-go-current ()
2341 "Go to a particular URL which is read from the minibuffer.
2342 Unlike `elpher-go', the reader is initialized with the URL of the
2345 (let* ((address (elpher-page-address elpher-current-page))
2346 (url (read-string (format "Visit URL (default scheme %s): "
2347 (elpher-get-default-url-scheme))
2348 (elpher-address-to-url address))))
2349 (let ((trimmed-url (string-trim url)))
2350 (unless (string-empty-p trimmed-url)
2351 (elpher-with-clean-buffer
2353 (elpher-page-from-url trimmed-url (elpher-get-default-url-scheme))))))))
2355 (defun elpher-redraw ()
2356 "Redraw current page."
2358 (elpher-visit-page elpher-current-page))
2360 (defun elpher-reload ()
2361 "Reload current page."
2363 (elpher-reload-current-page))
2365 (defun elpher-toggle-tls ()
2366 "Toggle TLS encryption mode for gopher."
2368 (setq elpher-use-tls (not elpher-use-tls))
2370 (if (gnutls-available-p)
2371 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
2372 (setq elpher-use-tls nil)
2373 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
2374 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
2376 (defun elpher-view-raw ()
2377 "View raw server response for current page."
2379 (if (elpher-address-about-p (elpher-page-address elpher-current-page))
2380 (error "This page was not generated by a server")
2381 (elpher-visit-page elpher-current-page
2382 #'elpher-render-raw)))
2384 (defun elpher-back ()
2385 "Go to previous site."
2387 (elpher-visit-previous-page))
2389 (defun elpher-back-to-start ()
2390 "Go all the way back to the start page."
2392 (setq-local elpher-current-page nil)
2393 (setq-local elpher-history nil)
2394 (elpher-visit-page (elpher-make-start-page)))
2396 (defun elpher-download ()
2397 "Download the link at point."
2399 (let ((button (button-at (point))))
2401 (let ((page (button-get button 'elpher-page)))
2403 (error "Not an elpher page"))
2404 (when (elpher-address-about-p (elpher-page-address page))
2405 (error "Cannot download %s" (elpher-page-display-string page)))
2406 (elpher-visit-page (button-get button 'elpher-page)
2407 #'elpher-render-download))
2408 (error "No link selected"))))
2410 (defun elpher-download-current ()
2411 "Download the current page."
2413 (if (elpher-address-about-p (elpher-page-address elpher-current-page))
2414 (error "Cannot download %s"
2415 (elpher-page-display-string elpher-current-page))
2416 (elpher-visit-page elpher-current-page
2417 #'elpher-render-download
2420 (defun elpher--build-link-map ()
2421 "Build alist mapping link names to destination pages in current buffer."
2422 (let ((link-map nil)
2423 (b (next-button (point-min) t)))
2425 (push (cons (button-label b) b) link-map)
2426 (setq b (next-button (button-start b))))
2429 (defun elpher-jump ()
2430 "Select a directory entry by name. Similar to the info browser (m)enu command."
2432 (let* ((link-map (elpher--build-link-map)))
2434 (let ((key (let ((completion-ignore-case t))
2435 (completing-read "Directory item/link: "
2437 (if (and key (> (length key) 0))
2438 (let ((b (cdr (assoc key link-map))))
2439 (goto-char (button-start b))
2440 (button-activate b)))))))
2442 (defun elpher-root-dir ()
2443 "Visit root of current server."
2445 (let ((address (elpher-page-address elpher-current-page)))
2446 (if (not (elpher-address-about-p address))
2447 (if (or (member (url-filename address) '("/" ""))
2448 (and (elpher-address-gopher-p address)
2449 (= (length (elpher-gopher-address-selector address)) 0)))
2450 (error "Already at root directory of current server")
2451 (let ((address-copy (elpher-address-from-url
2452 (elpher-address-to-url address))))
2453 (setf (url-filename address-copy) "")
2454 (elpher-go (elpher-address-to-url address-copy))))
2455 (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
2457 (defun elpher-info-page (page)
2458 "Display URL of PAGE in minibuffer."
2459 (let* ((address (elpher-page-address page))
2460 (url (elpher-address-to-url address))
2461 (iri (elpher-address-to-iri address)))
2464 (message "%s (Raw: %s)" iri url))))
2466 (defun elpher-info-link ()
2467 "Display information on page corresponding to link at point."
2469 (let ((button (button-at (point))))
2471 (error "No item selected"))
2472 (let ((page (button-get button 'elpher-page)))
2474 (error "Not an elpher page"))
2475 (elpher-info-page page))))
2477 (defun elpher-info-current ()
2478 "Display information on current page."
2480 (elpher-info-page elpher-current-page))
2482 (defun elpher-copy-page-url (page)
2483 "Copy URL representation of address of PAGE to `kill-ring'."
2484 (let* ((address (elpher-page-address page))
2485 (url (elpher-address-to-url address)))
2486 (message "Copied \"%s\" to kill-ring/clipboard." url)
2489 (defun elpher-copy-link-url ()
2490 "Copy URL of item at point to `kill-ring'."
2492 (let ((button (button-at (point))))
2494 (error "No item selected"))
2495 (let ((page (button-get button 'elpher-page)))
2497 (error "Not an elpher page"))
2498 (elpher-copy-page-url page))))
2500 (defun elpher-copy-current-url ()
2501 "Copy URL of current page to `kill-ring'."
2503 (elpher-copy-page-url elpher-current-page))
2505 (defun elpher-set-gopher-coding-system ()
2506 "Specify an explicit character coding system for gopher selectors."
2508 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
2509 (setq elpher-user-coding-system system)
2511 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
2512 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
2518 (defvar elpher-mode-map
2519 (let ((map (make-sparse-keymap)))
2520 (define-key map (kbd "TAB") 'elpher-next-link)
2521 (define-key map (kbd "<backtab>") 'elpher-prev-link)
2522 (define-key map (kbd "C-M-i") 'elpher-prev-link)
2523 (define-key map (kbd "u") 'elpher-back)
2524 (define-key map (kbd "-") 'elpher-back)
2525 (define-key map (kbd "^") 'elpher-back)
2526 (define-key map [mouse-3] 'elpher-back)
2527 (define-key map (kbd "U") 'elpher-back-to-start)
2528 (define-key map (kbd "g") 'elpher-go)
2529 (define-key map (kbd "o") 'elpher-go-current)
2530 (define-key map (kbd "O") 'elpher-root-dir)
2531 (define-key map (kbd "s") 'elpher-show-history)
2532 (define-key map (kbd "S") 'elpher-show-visited-pages)
2533 (define-key map (kbd "r") 'elpher-redraw)
2534 (define-key map (kbd "R") 'elpher-reload)
2535 (define-key map (kbd "T") 'elpher-toggle-tls)
2536 (define-key map (kbd ".") 'elpher-view-raw)
2537 (define-key map (kbd "d") 'elpher-download)
2538 (define-key map (kbd "D") 'elpher-download-current)
2539 (define-key map (kbd "m") 'elpher-jump)
2540 (define-key map (kbd "i") 'elpher-info-link)
2541 (define-key map (kbd "I") 'elpher-info-current)
2542 (define-key map (kbd "c") 'elpher-copy-link-url)
2543 (define-key map (kbd "C") 'elpher-copy-current-url)
2544 (define-key map (kbd "a") 'elpher-bookmark-link)
2545 (define-key map (kbd "A") 'elpher-bookmark-current)
2546 (define-key map (kbd "B") 'elpher-show-bookmarks)
2547 (define-key map (kbd "!") 'elpher-set-gopher-coding-system)
2548 (define-key map (kbd "F") 'elpher-forget-current-certificate)
2549 (when (fboundp 'evil-define-key*)
2552 (kbd "TAB") 'elpher-next-link
2553 (kbd "C-") 'elpher-follow-current-link
2554 (kbd "C-t") 'elpher-back
2555 (kbd "u") 'elpher-back
2556 (kbd "-") 'elpher-back
2557 (kbd "^") 'elpher-back
2558 [mouse-3] 'elpher-back
2559 (kbd "U") 'elpher-back-to-start
2560 (kbd "g") 'elpher-go
2561 (kbd "o") 'elpher-go-current
2562 (kbd "O") 'elpher-root-dir
2563 (kbd "s") 'elpher-show-history
2564 (kbd "S") 'elpher-show-visited-pages
2565 (kbd "r") 'elpher-redraw
2566 (kbd "R") 'elpher-reload
2567 (kbd "T") 'elpher-toggle-tls
2568 (kbd ".") 'elpher-view-raw
2569 (kbd "d") 'elpher-download
2570 (kbd "D") 'elpher-download-current
2571 (kbd "m") 'elpher-jump
2572 (kbd "i") 'elpher-info-link
2573 (kbd "I") 'elpher-info-current
2574 (kbd "c") 'elpher-copy-link-url
2575 (kbd "C") 'elpher-copy-current-url
2576 (kbd "a") 'elpher-bookmark-link
2577 (kbd "A") 'elpher-bookmark-current
2578 (kbd "B") 'elpher-show-bookmarks
2579 (kbd "!") 'elpher-set-gopher-coding-system
2580 (kbd "F") 'elpher-forget-current-certificate))
2582 "Keymap for gopher client.")
2584 (define-derived-mode elpher-mode special-mode "elpher"
2585 "Major mode for elpher, an elisp gopher client.
2587 This mode is automatically enabled by the interactive
2588 functions which initialize the client, namely
2589 `elpher', and `elpher-go'."
2590 (setq-local elpher-current-page nil)
2591 (setq-local elpher-history nil)
2592 (setq-local elpher-buffer-name (buffer-name))
2593 (setq-local bookmark-make-record-function #'elpher-bookmark-make-record)
2594 (setq-local imenu-create-index-function #'elpher-build-current-imenu-index))
2596 (when (fboundp 'evil-set-initial-state)
2597 (evil-set-initial-state 'elpher-mode 'motion))
2600 ;;; Main start procedure
2604 (defun elpher (&optional arg)
2605 "Start elpher with default landing page.
2606 The buffer used for Elpher sessions is determined by the value of
2607 ‘elpher-buffer-name’. If there is already an Elpher session active in
2608 that buffer, Emacs will simply switch to it. Otherwise, a new session
2609 will begin. A numeric prefix ARG (as in ‘\\[universal-argument] 42
2610 \\[execute-extended-command] elpher RET’) switches to the session with
2611 that number, creating it if necessary. A non numeric prefix ARG means
2612 to create a new session. Returns the buffer selected (or created)."
2614 (let* ((name (default-value 'elpher-buffer-name))
2615 (buf (cond ((numberp arg)
2616 (get-buffer-create (format "%s<%d>" name arg)))
2618 (generate-new-buffer name))
2620 (get-buffer-create name)))))
2621 (pop-to-buffer-same-window buf)
2622 (unless (buffer-modified-p)
2624 (elpher-visit-page (elpher-make-start-page))
2625 "Started Elpher."))); Otherwise (elpher) evaluates to start page string.
2627 ;;; elpher.el ends here