1 ;;; elpher.el --- A friendly gopher and gemini client -*- lexical-binding: t -*-
3 ;; Copyright (C) 2021 Jens Östlund <jostlund@gmail.com>
4 ;; Copyright (C) 2021 F. Jason Park <jp@neverwas.me>
5 ;; Copyright (C) 2021 Christopher Brannon <chris@the-brannons.com>
6 ;; Copyright (C) 2021 Omar Polo <op@omarpolo.com>
7 ;; Copyright (C) 2021 Noodles! <nnoodle@chiru.no>
8 ;; Copyright (C) 2021 Abhiseck Paira <abhiseckpaira@disroot.org>
9 ;; Copyright (C) 2020-2021 Alex Schroeder <alex@gnu.org>
10 ;; Copyright (C) 2020 Zhiwei Chen <chenzhiwei03@kuaishou.com>
11 ;; Copyright (C) 2020 condy0919 <condy0919@gmail.com>
12 ;; Copyright (C) 2020 Alexis <flexibeast@gmail.com>
13 ;; Copyright (C) 2020 Étienne Deparis <etienne@depar.is>
14 ;; Copyright (C) 2020 Simon Nicolussi <sinic@sinic.name>
15 ;; Copyright (C) 2020 Michel Alexandre Salim <michel@michel-slm.name>
16 ;; Copyright (C) 2020 Koushk Roy <kroy@twilio.com>
17 ;; Copyright (C) 2020 Vee <vee@vnsf.xyz>
18 ;; Copyright (C) 2020 Simon South <simon@simonsouth.net>
19 ;; Copyright (C) 2019-2021 Tim Vaughan <plugd@thelambdalab.xyz>
21 ;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
22 ;; Created: 11 April 2019
24 ;; Keywords: comm gopher
25 ;; Homepage: https://thelambdalab.xyz/elpher
26 ;; Package-Requires: ((emacs "27.1"))
28 ;; This file is not part of GNU Emacs.
30 ;; This program is free software: you can redistribute it and/or modify
31 ;; it under the terms of the GNU General Public License as published by
32 ;; the Free Software Foundation, either version 3 of the License, or
33 ;; (at your option) any later version.
35 ;; This program is distributed in the hope that it will be useful,
36 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
37 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
38 ;; GNU General Public License for more details.
40 ;; You should have received a copy of the GNU General Public License
41 ;; along with this file. If not, see <http://www.gnu.org/licenses/>.
45 ;; Elpher aims to provide a practical and friendly gopher and gemini
46 ;; client for GNU Emacs. It supports:
48 ;; - intuitive keyboard and mouse-driven browsing,
49 ;; - out-of-the-box compatibility with evil-mode,
50 ;; - clickable web and gopher links *in plain text*,
51 ;; - caching of visited sites,
52 ;; - pleasant and configurable colouring of Gopher directories,
53 ;; - direct visualisation of image files,
54 ;; - gopher connections using TLS encryption,
55 ;; - the fledgling Gemini protocol,
56 ;; - the greybeard Finger protocol.
58 ;; To launch Elpher, simply use 'M-x elpher'. This will open a start
59 ;; page containing information on key bindings and suggested starting
60 ;; points for your gopher exploration.
62 ;; Full instructions can be found in the Elpher info manual.
64 ;; Elpher is under active development. Any suggestions for
65 ;; improvements are welcome, and can be made on the official project
66 ;; page, gopher://thelambdalab.xyz/1/projects/elpher, or via the
67 ;; project mailing list at https://lists.sr.ht/~michel-slm/elpher.
88 (defconst elpher-version "3.1.0"
89 "Current version of elpher.")
91 (defconst elpher-margin-width 6
92 "Width of left-hand margin used when rendering indicies.")
94 (defconst elpher-type-map
95 '(((gopher ?0) elpher-get-gopher-page elpher-render-text "txt" elpher-text)
96 ((gopher ?1) elpher-get-gopher-page elpher-render-index "/" elpher-index)
97 ((gopher ?4) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
98 ((gopher ?5) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
99 ((gopher ?7) elpher-get-gopher-query-page elpher-render-index "?" elpher-search)
100 ((gopher ?9) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
101 ((gopher ?g) elpher-get-gopher-page elpher-render-image "img" elpher-image)
102 ((gopher ?p) elpher-get-gopher-page elpher-render-image "img" elpher-image)
103 ((gopher ?I) elpher-get-gopher-page elpher-render-image "img" elpher-image)
104 ((gopher ?d) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
105 ((gopher ?P) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
106 ((gopher ?s) elpher-get-gopher-page elpher-render-download "snd" elpher-binary)
107 ((gopher ?h) elpher-get-gopher-page elpher-render-html "htm" elpher-html)
108 (gemini elpher-get-gemini-page elpher-render-gemini "gem" elpher-gemini)
109 (finger elpher-get-finger-page elpher-render-text "txt" elpher-text)
110 (telnet elpher-get-telnet-page nil "tel" elpher-telnet)
111 (other-url elpher-get-other-url-page nil "url" elpher-other-url)
112 ((special start) elpher-get-start-page nil "E" elpher-index)
113 ((special bookmarks) elpher-get-bookmarks-page nil "E" elpher-index)
114 ((special history) elpher-get-history-page nil "E" elpher-index)
115 ((special visited-pages) elpher-get-visited-pages-page nil "E" elpher-index))
116 "Association list from types to getters, renderers, margin codes and index faces.")
119 ;;; Declarations to avoid compiler warnings.
123 (declare-function ansi-color-filter-apply "ansi-color")
124 (declare-function ansi-color-apply "ansi-color")
125 (declare-function bookmark-store "bookmark")
126 (declare-function org-link-store-props "ol")
127 (declare-function org-link-set-parameters "ol")
128 (defvar ansi-color-context)
129 (defvar bookmark-make-record-function)
130 (defvar mu4e~view-beginning-of-url-regexp)
131 (defvar thing-at-point-uri-schemes)
132 (defvar xterm-color-preserve-properties))
135 ;;; Customization group
139 "A gopher and gemini client."
140 :group 'applications)
142 ;; General appearance and customizations
144 (defcustom elpher-open-urls-with-eww nil
145 "If non-nil, open URL selectors using eww.
146 Otherwise, use the system browser via the `browse-url' function."
149 (defcustom elpher-use-header t
150 "If non-nil, display current page information in buffer header."
153 (defcustom elpher-auto-disengage-TLS nil
154 "If non-nil, automatically disengage TLS following an unsuccessful connection.
155 While enabling this may seem convenient, it is also potentially
156 dangerous as it allows switching from an encrypted channel back to
157 plain text without user input."
160 (defcustom elpher-connection-timeout 5
161 "Specifies the number of seconds to wait for a network connection to time out."
164 (defcustom elpher-filter-ansi-from-text nil
165 "If non-nil, filter ANSI escape sequences from text.
166 The default behaviour is to use the ansi-color package to interpret these
170 (defcustom elpher-certificate-directory
171 (file-name-as-directory (locate-user-emacs-file "elpher-certificates"))
172 "Specify the name of the directory where client certificates will be stored.
173 These certificates may be used for establishing authenticated TLS connections."
176 (defcustom elpher-openssl-command "openssl"
177 "The command used to launch openssl when generating TLS client certificates."
180 (defcustom elpher-default-url-type "gopher"
181 "Default URL type (i.e. scheme) to assume if not explicitly given."
182 :type '(choice (const "gopher")
185 (defcustom elpher-gemini-TLS-cert-checks nil
186 "If non-nil, verify gemini server TLS certs using the default security level.
187 Otherwise, certificate verification is disabled.
189 This defaults to off because it is standard practice for Gemini servers
190 to use self-signed certificates, meaning that most servers provide what
191 EMACS considers to be an invalid certificate."
194 (defcustom elpher-gemini-max-fill-width 80
195 "Specify the maximum default width (in columns) of text/gemini documents.
196 The actual width used is the minimum of this value and the window width at
197 the time when the text is rendered."
200 (defcustom elpher-gemini-link-string "→ "
201 "Specify the string used to indicate links when rendering gemini maps.
205 (defcustom elpher-gemini-bullet-string "•"
206 "Specify the string used for bullets when rendering gemini maps."
209 (defcustom elpher-ipv4-always nil
210 "If non-nil, elpher will always use IPv4 to establish network connections.
211 This can be useful when browsing from a computer that supports IPv6, because
212 some servers which do not support IPv6 can take a long time to time-out."
215 (defcustom elpher-socks-always nil
216 "If non-nil, elpher will establish network connections over a SOCKS proxy.
217 Otherwise, the SOCKS proxy is only used for connections to onion services."
220 (defcustom elpher-use-emacs-bookmark-menu nil
221 "If non-nil, elpher will only use the native Emacs bookmark menu.
222 Otherwise, \\[elpher-show-bookmarks] will visit a special elpher bookmark
223 page within which all of the standard elpher keybindings are active."
226 ;; Face customizations
228 (defgroup elpher-faces nil
229 "Elpher face customizations."
232 (defface elpher-index
233 '((t :inherit font-lock-keyword-face))
234 "Face used for directory type directory records.")
238 "Face used for text type directory records.")
241 '((t :inherit default))
242 "Face used for info type directory records.")
244 (defface elpher-image
245 '((t :inherit font-lock-string-face))
246 "Face used for image type directory records.")
248 (defface elpher-search
249 '((t :inherit warning))
250 "Face used for search type directory records.")
253 '((t :inherit font-lock-comment-face))
254 "Face used for html type directory records.")
256 (defface elpher-gemini
257 '((t :inherit font-lock-constant-face))
258 "Face used for Gemini type directory records.")
260 (defface elpher-other-url
261 '((t :inherit font-lock-comment-face))
262 "Face used for other URL type links records.")
264 (defface elpher-telnet
265 '((t :inherit font-lock-function-name-face))
266 "Face used for telnet type directory records.")
268 (defface elpher-binary
269 '((t :inherit font-lock-doc-face))
270 "Face used for binary type directory records.")
272 (defface elpher-unknown
273 '((t :inherit error))
274 "Face used for directory records with unknown/unsupported types.")
276 (defface elpher-margin-key
278 "Face used for directory margin key.")
280 (defface elpher-margin-brackets
281 '((t :inherit shadow))
282 "Face used for brackets around directory margin key.")
284 (defface elpher-gemini-heading1
285 '((t :inherit bold :height 1.8))
286 "Face used for gemini heading level 1.")
288 (defface elpher-gemini-heading2
289 '((t :inherit bold :height 1.5))
290 "Face used for gemini heading level 2.")
292 (defface elpher-gemini-heading3
293 '((t :inherit bold :height 1.2))
294 "Face used for gemini heading level 3.")
296 (defface elpher-gemini-preformatted
297 '((t :inherit fixed-pitch))
298 "Face used for pre-formatted gemini text blocks.")
300 (defface elpher-gemini-quoted
301 '((t :inherit font-lock-doc-face))
302 "Face used for gemini quoted texts.")
309 ;; An elpher "address" object is either a url object or a symbol.
310 ;; Symbol addresses are "special", corresponding to pages generated
311 ;; dynamically for and by elpher. All others represent pages which
312 ;; rely on content retrieved over the network.
314 (defun elpher-address-from-url (url-string)
315 "Create a ADDRESS object corresponding to the given URL-STRING."
316 (let ((data (match-data))) ; Prevent parsing clobbering match data
318 (let ((url (url-generic-parse-url url-string)))
319 (unless (and (not (url-fullness url)) (url-type url))
320 (setf (url-fullness url) t)
321 (unless (url-type url)
322 (setf (url-type url) elpher-default-url-type))
323 (unless (url-host url)
324 (let ((p (split-string (url-filename url) "/" nil nil)))
325 (setf (url-host url) (car p))
326 (setf (url-filename url)
328 (concat "/" (mapconcat #'identity (cdr p) "/"))
330 (when (or (equal "gopher" (url-type url))
331 (equal "gophers" (url-type url)))
333 (when (or (equal (url-filename url) "")
334 (equal (url-filename url) "/"))
335 (setf (url-filename url) "/1")))
336 (when (equal "gemini" (url-type url))
338 (if (equal (url-filename url) "")
339 (setf (url-filename url) "/"))))
340 (elpher-remove-redundant-ports url))
341 (set-match-data data))))
343 (defun elpher-remove-redundant-ports (address)
344 "Remove redundant port specifiers from ADDRESS.
345 Here 'redundant' means that the specified port matches the default
346 for that protocol, eg 70 for gopher."
347 (if (and (not (elpher-address-special-p address))
348 (eq (url-portspec address) ; (url-port) is too slow!
349 (pcase (url-type address)
351 ((or "gopher" "gophers") 70)
354 (setf (url-portspec address) nil))
357 (defun elpher-make-gopher-address (type selector host port &optional tls)
358 "Create an ADDRESS object using gopher directory record attributes.
359 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
360 If the optional attribute TLS is non-nil, the address will be marked as
361 requiring gopher-over-TLS."
363 ((equal type ?i) nil)
364 ((and (equal type ?h)
365 (string-prefix-p "URL:" selector))
366 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
368 (elpher-address-from-url
371 ":" (number-to-string port))))
373 (elpher-address-from-url
374 (concat "gopher" (if tls "s" "")
376 ":" (number-to-string port)
380 (defun elpher-make-special-address (type)
381 "Create an ADDRESS object corresponding to the given special address symbol TYPE."
384 (defun elpher-address-to-url (address)
385 "Get string representation of ADDRESS, or nil if ADDRESS is special."
386 (if (elpher-address-special-p address)
388 (url-encode-url (url-recreate-url address))))
390 (defun elpher-address-type (address)
391 "Retrieve type of ADDRESS object.
392 This is used to determine how to retrieve and render the document the
393 address refers to, via the table `elpher-type-map'."
394 (if (symbolp address)
395 (list 'special address)
396 (let ((protocol (url-type address)))
397 (cond ((or (equal protocol "gopher")
398 (equal protocol "gophers"))
400 (if (member (url-filename address) '("" "/"))
402 (string-to-char (substring (url-filename address) 1)))))
403 ((equal protocol "gemini")
405 ((equal protocol "telnet")
407 ((equal protocol "finger")
411 (defun elpher-address-protocol (address)
412 "Retrieve the transport protocol for ADDRESS. This is nil for special addresses."
413 (if (symbolp address)
417 (defun elpher-address-filename (address)
418 "Retrieve the filename component of ADDRESS.
419 For gopher addresses this is a combination of the selector type and selector."
420 (if (symbolp address)
422 (url-unhex-string (url-filename address))))
424 (defun elpher-address-host (address)
425 "Retrieve host from ADDRESS object."
428 (defun elpher-address-user (address)
429 "Retrieve user from ADDRESS object."
432 (defun elpher-address-port (address)
433 "Retrieve port from ADDRESS object.
434 If no address is defined, returns 0. (This is for compatibility with the URL library.)"
435 (if (symbolp address)
439 (defun elpher-address-special-p (address)
440 "Return non-nil if ADDRESS object is special (e.g. start page page)."
443 (defun elpher-address-gopher-p (address)
444 "Return non-nill if ADDRESS object is a gopher address."
445 (and (not (elpher-address-special-p address))
446 (member (elpher-address-protocol address) '("gopher" "gophers"))))
448 (defun elpher-gopher-address-selector (address)
449 "Retrieve gopher selector from ADDRESS object."
450 (if (member (url-filename address) '("" "/"))
452 (url-unhex-string (substring (url-filename address) 2))))
457 (defvar elpher-content-cache (make-hash-table :test 'equal))
458 (defvar elpher-pos-cache (make-hash-table :test 'equal))
460 (defun elpher-get-cached-content (address)
461 "Retrieve the cached content for ADDRESS, or nil if none exists."
462 (gethash address elpher-content-cache))
464 (defun elpher-cache-content (address content)
465 "Set the content cache for ADDRESS to CONTENT."
466 (puthash address content elpher-content-cache))
468 (defun elpher-get-cached-pos (address)
469 "Retrieve the cached cursor position for ADDRESS, or nil if none exists."
470 (gethash address elpher-pos-cache))
472 (defun elpher-cache-pos (address pos)
473 "Set the cursor position cache for ADDRESS to POS."
474 (puthash address pos elpher-pos-cache))
479 (defun elpher-make-page (display-string address)
480 "Create a page with DISPLAY-STRING and ADDRESS."
481 (list display-string address))
483 (defun elpher-make-start-page ()
484 "Create the start page."
485 (elpher-make-page "Elpher Start Page"
486 (elpher-make-special-address 'start)))
488 (defun elpher-page-display-string (page)
489 "Retrieve the display string corresponding to PAGE."
492 (defun elpher-page-address (page)
493 "Retrieve the address corresponding to PAGE."
496 (defun elpher-page-set-address (page new-address)
497 "Set the address corresponding to PAGE to NEW-ADDRESS."
498 (setcar (cdr page) new-address))
500 (defvar elpher-current-page nil
501 "The current page for this Elpher buffer.")
503 (defvar elpher-history nil
504 "The local history stack for this Elpher buffer.
505 This variable is used by `elpher-back' and
506 `elpher-show-history'.")
508 (defvar elpher-visited-pages nil
509 "The global history for all Elpher buffers.
510 This variable is used by `elpher-show-visited-pages'.")
512 (defun elpher-visit-page (page &optional renderer no-history)
513 "Visit PAGE using its own renderer or RENDERER, if non-nil.
514 Additionally, push PAGE onto the history stack and the list of
515 previously-visited pages,unless NO-HISTORY is non-nil."
517 (elpher-process-cleanup)
519 (unless (equal (elpher-page-address elpher-current-page)
520 (elpher-page-address page))
521 (push elpher-current-page elpher-history)
522 (unless (or (elpher-address-special-p (elpher-page-address page))
523 (and elpher-visited-pages
524 (equal page (car elpher-visited-pages))))
525 (push page elpher-visited-pages))))
526 (setq-local elpher-current-page page)
527 (let* ((address (elpher-page-address page))
528 (type (elpher-address-type address))
529 (type-record (cdr (assoc type elpher-type-map))))
531 (funcall (car type-record)
535 (elpher-visit-previous-page)
537 (`(gopher ,type-char)
538 (error "Unsupported gopher selector type '%c' for '%s'"
539 type-char (elpher-address-to-url address)))
541 (error "Unsupported address type '%S' for '%s'"
542 other (elpher-address-to-url address)))))))
544 (defun elpher-visit-previous-page ()
545 "Visit the previous page in the history."
546 (let ((previous-page (pop elpher-history)))
548 (elpher-visit-page previous-page nil t)
549 (error "No previous page"))))
551 (defun elpher-reload-current-page ()
552 "Reload the current page, discarding any existing cached content."
553 (elpher-cache-content (elpher-page-address elpher-current-page) nil)
554 (elpher-visit-page elpher-current-page))
556 (defun elpher-save-pos ()
557 "Save the current position of point to the current page."
558 (when elpher-current-page
559 (elpher-cache-pos (elpher-page-address elpher-current-page) (point))))
561 (defun elpher-restore-pos ()
562 "Restore the position of point to that cached in the current page."
563 (let ((pos (elpher-get-cached-pos (elpher-page-address elpher-current-page))))
566 (goto-char (point-min)))))
569 ;;; Buffer preparation
572 (defvar elpher-buffer-name "*elpher*"
573 "The default name of the Elpher buffer.")
575 (defun elpher-update-header ()
576 "If `elpher-use-header' is true, display current page info in window header."
577 (if elpher-use-header
578 (let* ((display-string (elpher-page-display-string elpher-current-page))
579 (address (elpher-page-address elpher-current-page))
580 (tls-string (if (and (not (elpher-address-special-p address))
581 (member (elpher-address-protocol address)
582 '("gophers" "gemini")))
585 (header (concat display-string
586 (propertize tls-string 'face 'bold))))
587 (setq header-line-format header))))
589 (defmacro elpher-with-clean-buffer (&rest args)
590 "Evaluate ARGS with a clean *elpher* buffer as current."
591 (declare (debug (body))) ;; Allow edebug to step through body
592 `(with-current-buffer elpher-buffer-name
593 (unless (eq major-mode 'elpher-mode)
594 ;; avoid resetting buffer-local variables
596 (let ((inhibit-read-only t)
597 (ansi-color-context nil)) ;; clean ansi interpreter state
598 (setq-local network-security-level
599 (default-value 'network-security-level))
601 (elpher-update-header)
604 (defun elpher-buffer-message (string &optional line)
605 "Replace first line in elpher buffer with STRING.
606 If LINE is non-nil, replace that line instead."
607 (with-current-buffer elpher-buffer-name
608 (let ((inhibit-read-only t))
609 (goto-char (point-min))
612 (let ((data (match-data)))
615 (re-search-forward "^.*$")
616 (replace-match string))
617 (set-match-data data))))))
623 (defvar elpher-user-coding-system nil
624 "User-specified coding system to use for decoding text responses.")
626 (defun elpher-decode (string)
627 "Decode STRING using autodetected or user-specified coding system."
628 (decode-coding-string string
629 (if elpher-user-coding-system
630 elpher-user-coding-system
631 (detect-coding-string string t))))
633 (defun elpher-preprocess-text-response (string)
634 "Preprocess text selector response contained in STRING.
635 This involes decoding the character representation, and clearing
636 away CRs and any terminating period."
637 (elpher-decode (replace-regexp-in-string "\n\\.\n$" "\n"
638 (replace-regexp-in-string "\r" "" string))))
642 (defconst elpher-url-regex
643 "\\([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_~?/@|#-]\\)?\\)?"
644 "Regexp used to locate and buttonify URLs in text files loaded by elpher.")
646 (defun elpher-buttonify-urls (string)
647 "Turn substrings which look like urls in STRING into clickable buttons."
650 (goto-char (point-min))
651 (while (re-search-forward elpher-url-regex nil t)
652 (let ((page (elpher-make-page (substring-no-properties (match-string 0))
653 (elpher-address-from-url (match-string 0)))))
654 (make-text-button (match-beginning 0)
657 'action #'elpher-click-link
659 'help-echo #'elpher--page-button-help
663 ;;; ANSI colors or XTerm colors (application and filtering)
665 (or (require 'xterm-color nil t)
666 (require 'ansi-color))
668 (defalias 'elpher-color-filter-apply
669 (if (fboundp 'xterm-color-filter)
671 (let ((_xterm-color-render nil))
672 (xterm-color-filter s)))
673 #'ansi-color-filter-apply)
674 "A function to filter out ANSI escape sequences.")
676 (defalias 'elpher-color-apply
677 (if (fboundp 'xterm-color-filter)
680 "A function to apply ANSI escape sequences.")
682 ;;; Processing text for display
684 (defun elpher-process-text-for-display (string)
685 "Perform any desired processing of STRING prior to display as text.
686 Currently includes buttonifying URLs and processing ANSI escape codes."
687 (elpher-buttonify-urls (if elpher-filter-ansi-from-text
688 (elpher-color-filter-apply string)
689 (elpher-color-apply string))))
692 ;;; Network error reporting
695 (defun elpher-network-error (address error)
696 "Display ERROR message following unsuccessful negotiation with ADDRESS.
697 ERROR can be either an error object or a string."
698 (elpher-with-clean-buffer
699 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
700 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
701 (if (stringp error) error (error-message-string error)) "\n"
702 (propertize "\n----------------\n\n" 'face 'error)
703 "Press 'u' to return to the previous page.")))
706 ;;; General network communication
709 (defvar elpher-network-timer nil
710 "Timer used for network connections.")
712 (defvar elpher-use-tls nil
713 "If non-nil, use TLS to communicate with gopher servers.")
715 (defvar elpher-client-certificate nil
716 "If non-nil, contains client certificate details to use for TLS connections.")
718 (defun elpher-process-cleanup ()
719 "Immediately shut down any extant elpher process and timers."
720 (let ((p (get-process "elpher-process")))
721 (if p (delete-process p)))
722 (if (timerp elpher-network-timer)
723 (cancel-timer elpher-network-timer)))
725 (defun elpher-make-network-timer (thunk)
726 "Create a timer to run the THUNK after `elpher-connection-timeout' seconds.
727 This is just a wraper around `run-at-time' which additionally sets the
728 buffer-local variable `elpher-network-timer' to allow
729 `elpher-process-cleanup' to also clear the timer."
730 (let ((timer (run-at-time elpher-connection-timeout nil thunk)))
731 (setq-local elpher-network-timer timer)
734 (defun elpher-get-host-response (address default-port query-string response-processor
735 &optional use-tls force-ipv4)
736 "Generic function for retrieving data from ADDRESS.
738 When ADDRESS lacks a specific port, DEFAULT-PORT is used instead.
739 QUERY-STRING is a string sent to the host specified by ADDRESS to
740 illicet a response. This response is passed as an argument to the
741 function RESPONSE-PROCESSOR.
743 If non-nil, USE-TLS specifies that the connection is to be made over
744 TLS. If set to gemini, the certificate verification will be disabled
745 unless `elpher-gemini-TLS-cert-checks' is non-nil.
747 If non-nil, FORCE-IPV4 causes the network connection to be made over
748 ipv4 only. (The default behaviour when this is not set depends on
749 the host operating system and the local network capabilities.)"
750 (if (and use-tls (not (gnutls-available-p)))
751 (error "Use of TLS requires Emacs to be compiled with GNU TLS support")
752 (unless (< (elpher-address-port address) 65536)
753 (error "Cannot establish network connection: port number > 65536"))
754 (when (and (eq use-tls 'gemini) (not elpher-gemini-TLS-cert-checks))
755 (setq-local network-security-level 'low)
756 (setq-local gnutls-verify-error nil))
758 (let* ((kill-buffer-query-functions nil)
759 (port (elpher-address-port address))
760 (host (elpher-address-host address))
761 (service (if (> port 0) port default-port))
762 (response-string-parts nil)
765 (socks (or elpher-socks-always (string-suffix-p ".onion" host)))
766 (gnutls-params (list :type 'gnutls-x509pki
769 (elpher-get-current-keylist address)))
770 (timer (elpher-make-network-timer
772 (elpher-process-cleanup)
774 ; Try again with IPv4
775 ((not (or force-ipv4 socks))
776 (message "Connection timed out. Retrying with IPv4.")
777 (elpher-get-host-response address default-port
782 (not (eq use-tls 'gemini))
783 (or elpher-auto-disengage-TLS
785 "TLS connetion failed. Disable TLS mode and retry? ")))
786 (setq elpher-use-tls nil)
787 (elpher-get-host-response address default-port
792 (elpher-network-error address "Connection time-out."))))))
793 (proc (if socks (socks-open-network-stream "elpher-process" nil host service)
794 (make-network-process :name "elpher-process"
796 :family (and force-ipv4 'ipv4)
802 (cons 'gnutls-x509pki
803 (apply #'gnutls-boot-parameters
805 (setq elpher-network-timer timer)
806 (set-process-coding-system proc 'binary 'binary)
807 (set-process-query-on-exit-flag proc nil)
808 (elpher-buffer-message (concat "Connecting to " host "..."
809 " (press 'u' to abort)"))
810 (set-process-filter proc
811 (lambda (_proc string)
815 (setq bytes-received (+ bytes-received (length string)))
816 (let ((new-hkbytes-received (/ bytes-received 102400)))
817 (when (> new-hkbytes-received hkbytes-received)
818 (setq hkbytes-received new-hkbytes-received)
819 (elpher-buffer-message
821 (number-to-string (/ hkbytes-received 10.0))
824 (setq response-string-parts
825 (cons string response-string-parts))))
826 (set-process-sentinel proc
829 (cancel-timer timer))
830 (condition-case the-error
832 ((string-prefix-p "open" event) ; request URL
833 (elpher-buffer-message
834 (concat "Connected to " host ". Receiving data..."
835 " (press 'u' to abort)"))
836 (let ((inhibit-eol-conversion t))
837 (process-send-string proc query-string)))
838 ((string-prefix-p "deleted" event)) ; do nothing
839 ((and (not response-string-parts)
840 (not (or elpher-ipv4-always force-ipv4 socks)))
841 ; Try again with IPv4
842 (message "Connection failed. Retrying with IPv4.")
843 (elpher-get-host-response address default-port
847 (response-string-parts
848 (elpher-with-clean-buffer
849 (insert "Data received. Rendering..."))
850 (funcall response-processor
851 (apply #'concat (reverse response-string-parts)))
852 (elpher-restore-pos))
854 (error "No response from server")))
856 (elpher-network-error address the-error)))))
858 (if use-tls (apply #'gnutls-negotiate :process proc gnutls-params))
859 (funcall (process-sentinel proc) proc "open\n")))
861 (elpher-process-cleanup)
862 (error "Error initiating connection to server")))))
865 ;;; Client-side TLS Certificate Management
868 (defun elpher-generate-certificate (common-name key-file cert-file &optional temporary)
869 "Generate a key and a self-signed client TLS certificate using openssl.
871 The Common Name field of the certificate is set to COMMON-NAME. The
872 arguments KEY-FILE and CERT-FILE should contain the absolute paths of
873 the key and certificate files to write.
875 If TEMPORARY is non-nil, the certificate will be given an exporation
876 period of one day, and the key and certificate files will be deleted
877 when the certificate is no longer needed for the current session.
879 Otherwise, the certificate will be given a 100 year expiration period
880 and the files will not be deleted.
882 The function returns a list containing the current host name, the
883 temporary flag, and the key and cert file names in the form required
884 by `gnutls-boot-parameters`."
885 (let ((exp-key-file (expand-file-name key-file))
886 (exp-cert-file (expand-file-name cert-file)))
889 (call-process elpher-openssl-command nil nil nil
890 "req" "-x509" "-newkey" "rsa:2048"
891 "-days" (if temporary "1" "36500")
893 "-subj" (concat "/CN=" common-name)
894 "-keyout" exp-key-file
895 "-out" exp-cert-file)
896 (list (elpher-address-host (elpher-page-address elpher-current-page))
897 temporary exp-key-file exp-cert-file))
899 (message "Check that openssl is installed, or customize `elpher-openssl-command`.")
900 (error "Program 'openssl', required for certificate generation, not found")))))
902 (defun elpher-generate-throwaway-certificate ()
903 "Generate and return details of a throwaway certificate.
904 The key and certificate files will be deleted when they are no
905 longer needed for this session."
906 (let* ((file-base (make-temp-name "elpher"))
907 (key-file (concat temporary-file-directory file-base ".key"))
908 (cert-file (concat temporary-file-directory file-base ".crt")))
909 (elpher-generate-certificate file-base key-file cert-file t)))
911 (defun elpher-generate-persistent-certificate (file-base common-name)
912 "Generate and return details of a persistent certificate.
913 The argument FILE-BASE is used as the base for the key and certificate
914 files, while COMMON-NAME specifies the common name field of the
917 The key and certificate files are written to in `elpher-certificate-directory'."
918 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
919 (cert-file (concat elpher-certificate-directory file-base ".crt")))
920 (elpher-generate-certificate common-name key-file cert-file)))
922 (defun elpher-get-existing-certificate (file-base)
923 "Return a certificate object corresponding to an existing certificate.
924 It is assumed that the key files FILE-BASE.key and FILE-BASE.crt exist in
925 the directory `elpher-certificate-directory'."
926 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
927 (cert-file (concat elpher-certificate-directory file-base ".crt")))
928 (list (elpher-address-host (elpher-page-address elpher-current-page))
930 (expand-file-name key-file)
931 (expand-file-name cert-file))))
933 (defun elpher-install-and-use-existing-certificate (key-file-src cert-file-src file-base)
934 "Install a key+certificate file pair in `elpher-certificate-directory'.
935 The strings KEY-FILE-SRC and CERT-FILE-SRC are the existing key and
936 certificate files to install. The argument FILE-BASE is used as the
937 base for the installed key and certificate files."
938 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
939 (cert-file (concat elpher-certificate-directory file-base ".crt")))
940 (if (or (file-exists-p key-file)
941 (file-exists-p cert-file))
942 (error "A certificate with base name %s is already installed" file-base))
943 (copy-file key-file-src key-file)
944 (copy-file cert-file-src cert-file)
945 (list (elpher-address-host (elpher-page-address elpher-current-page))
947 (expand-file-name key-file)
948 (expand-file-name cert-file))))
950 (defun elpher-list-existing-certificates ()
951 "Return a list of the persistent certificates in `elpher-certificate-directory'."
952 (unless (file-directory-p elpher-certificate-directory)
953 (make-directory elpher-certificate-directory))
956 (file-name-sans-extension file))
957 (directory-files elpher-certificate-directory nil "\\.key$")))
959 (defun elpher-forget-current-certificate ()
960 "Causes any current certificate to be forgotten.)
961 In the case of throwaway certificates, the key and certificate files
964 (when elpher-client-certificate
965 (unless (and (called-interactively-p 'any)
966 (not (y-or-n-p (concat "Really forget client certificate? "
967 "(Throwaway certificates will be deleted.)"))))
968 (when (cadr elpher-client-certificate)
969 (delete-file (elt elpher-client-certificate 2))
970 (delete-file (elt elpher-client-certificate 3)))
971 (setq elpher-client-certificate nil)
972 (if (called-interactively-p 'any)
973 (message "Client certificate forgotten.")))))
975 (defun elpher-get-current-keylist (address)
976 "Retrieve the `gnutls-boot-parameters'-compatable keylist.
978 This is obtained from the client certificate described by
979 `elpher-current-certificate', if one is available and the host for
980 that certificate matches the host in ADDRESS.
982 If `elpher-current-certificate' is non-nil, and its host name doesn't
983 match that of ADDRESS, the certificate is forgotten."
984 (if elpher-client-certificate
985 (if (string= (car elpher-client-certificate)
986 (elpher-address-host address))
987 (list (cddr elpher-client-certificate))
988 (elpher-forget-current-certificate)
989 (message "Disabling client certificate for new host")
994 ;;; Gopher selector retrieval
997 (defun elpher-get-gopher-response (address renderer)
998 "Get response string from gopher server at ADDRESS and render using RENDERER."
999 (elpher-get-host-response address 70
1000 (concat (elpher-gopher-address-selector address) "\r\n")
1002 (or (string= (elpher-address-protocol address) "gophers")
1005 (defun elpher-get-gopher-page (renderer)
1006 "Getter function for gopher pages.
1007 The RENDERER procedure is used to display the contents of the page
1008 once they are retrieved from the gopher server."
1009 (let* ((address (elpher-page-address elpher-current-page))
1010 (content (elpher-get-cached-content address)))
1011 (if (and content (funcall renderer nil))
1012 (elpher-with-clean-buffer
1014 (elpher-restore-pos))
1015 (elpher-with-clean-buffer
1016 (insert "LOADING... (use 'u' to cancel)\n"))
1017 (condition-case the-error
1018 (elpher-get-gopher-response address renderer)
1020 (elpher-network-error address the-error))))))
1024 (defun elpher-insert-index (string)
1025 "Insert the index corresponding to STRING into the current buffer."
1026 ;; Should be able to split directly on CRLF, but some non-conformant
1027 ;; LF-only servers sadly exist, hence the following.
1028 (let ((str-processed (elpher-preprocess-text-response string)))
1029 (dolist (line (split-string str-processed "\n"))
1031 (unless (= (length line) 0)
1032 (let* ((type (elt line 0))
1033 (fields (split-string (substring line 1) "\t"))
1034 (display-string (elt fields 0))
1035 (selector (elt fields 1))
1036 (host (elt fields 2))
1037 (port (if (elt fields 3)
1038 (string-to-number (elt fields 3))
1040 (address (elpher-make-gopher-address type selector host port)))
1041 (elpher-insert-index-record display-string address)))))))
1043 (defun elpher-insert-margin (&optional type-name)
1044 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
1047 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
1049 (propertize "[" 'face 'elpher-margin-brackets)
1050 (propertize type-name 'face 'elpher-margin-key)
1051 (propertize "]" 'face 'elpher-margin-brackets))))
1053 (insert (make-string elpher-margin-width ?\s))))
1055 (defun elpher--page-button-help (_window buffer pos)
1056 "Function called by Emacs to generate mouse-over text.
1057 The arguments specify the BUFFER and the POS within the buffer of the item
1058 for which help is required. The function returns the help to be
1059 displayed. The _WINDOW argument is currently unused."
1060 (with-current-buffer buffer
1061 (let ((button (button-at pos)))
1063 (let* ((page (button-get button 'elpher-page))
1064 (address (elpher-page-address page)))
1065 (format "mouse-1, RET: open '%s'" (if (elpher-address-special-p address)
1067 (elpher-address-to-url address))))))))
1069 (defun elpher-insert-index-record (display-string &optional address)
1070 "Function to insert an index record into the current buffer.
1071 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
1072 If ADDRESS is not supplied or nil the record is rendered as an
1073 'information' line."
1074 (let* ((type (if address (elpher-address-type address) nil))
1075 (type-map-entry (cdr (assoc type elpher-type-map))))
1077 (let* ((margin-code (elt type-map-entry 2))
1078 (face (elt type-map-entry 3))
1079 (filtered-display-string (elpher-color-filter-apply display-string))
1080 (page (elpher-make-page filtered-display-string address)))
1081 (elpher-insert-margin margin-code)
1082 (insert-text-button filtered-display-string
1085 'action #'elpher-click-link
1087 'help-echo #'elpher--page-button-help))
1089 ('nil ;; Information
1090 (elpher-insert-margin)
1091 (let ((propertized-display-string
1092 (propertize display-string 'face 'elpher-info)))
1093 (insert (elpher-process-text-for-display propertized-display-string))))
1094 (`(gopher ,selector-type) ;; Unknown
1095 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
1096 (insert (propertize display-string
1097 'face 'elpher-unknown)))))
1100 (defun elpher-click-link (button)
1101 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
1102 (let ((page (button-get button 'elpher-page)))
1103 (elpher-visit-page page)))
1105 (defun elpher-render-index (data &optional _mime-type-string)
1106 "Render DATA as an index. MIME-TYPE-STRING is unused."
1107 (elpher-with-clean-buffer
1110 (elpher-insert-index data)
1111 (elpher-cache-content (elpher-page-address elpher-current-page)
1116 (defun elpher-render-text (data &optional _mime-type-string)
1117 "Render DATA as text. MIME-TYPE-STRING is unused."
1118 (elpher-with-clean-buffer
1121 (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
1122 (elpher-cache-content
1123 (elpher-page-address elpher-current-page)
1128 (defun elpher-render-image (data &optional _mime-type-string)
1129 "Display DATA as image. MIME-TYPE-STRING is unused."
1132 (if (display-images-p)
1133 (let* ((image (create-image
1136 (window (get-buffer-window elpher-buffer-name)))
1138 (setf (image-property image :max-width) (window-pixel-width window))
1139 (setf (image-property image :max-height) (window-pixel-height window)))
1140 (elpher-with-clean-buffer
1141 (insert-image image)
1142 (elpher-restore-pos)))
1143 (elpher-render-download data))))
1145 ;; Search retrieval and rendering
1147 (defun elpher-get-gopher-query-page (renderer)
1148 "Getter for gopher addresses requiring input.
1149 The response is rendered using the rendering function RENDERER."
1150 (let* ((address (elpher-page-address elpher-current-page))
1151 (content (elpher-get-cached-content address))
1153 (if (and content (funcall renderer nil))
1154 (elpher-with-clean-buffer
1156 (elpher-restore-pos)
1157 (message "Displaying cached search results. Reload to perform a new search."))
1159 (let* ((query-string (read-string "Query: "))
1160 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
1161 (search-address (elpher-make-gopher-address ?1
1163 (elpher-address-host address)
1164 (elpher-address-port address)
1165 (equal (elpher-address-type address) "gophers"))))
1168 (elpher-with-clean-buffer
1169 (insert "LOADING RESULTS... (use 'u' to cancel)"))
1170 (elpher-get-gopher-response search-address renderer))
1172 (elpher-visit-previous-page))))))
1174 ;; Raw server response rendering
1176 (defun elpher-render-raw (data &optional mime-type-string)
1177 "Display raw DATA in buffer. MIME-TYPE-STRING is also displayed if provided."
1180 (elpher-with-clean-buffer
1181 (when mime-type-string
1182 (insert "MIME type specified by server: '" mime-type-string "'\n"))
1184 (goto-char (point-min)))
1185 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
1187 ;; File save "rendering"
1189 (defun elpher-render-download (data &optional _mime-type-string)
1190 "Save DATA to file. MIME-TYPE-STRING is unused."
1193 (let* ((address (elpher-page-address elpher-current-page))
1194 (selector (if (elpher-address-gopher-p address)
1195 (elpher-gopher-address-selector address)
1196 (elpher-address-filename address))))
1197 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1198 (let* ((filename-proposal (file-name-nondirectory selector))
1199 (filename (read-file-name "Download complete. Save file as: "
1201 (if (> (length filename-proposal) 0)
1204 (let ((coding-system-for-write 'binary))
1205 (with-temp-file filename
1207 (message (format "Saved to file %s." filename))))))
1211 (defun elpher-render-html (data &optional _mime-type-string)
1212 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
1213 (elpher-with-clean-buffer
1216 (let ((dom (with-temp-buffer
1218 (libxml-parse-html-region (point-min) (point-max)))))
1219 (shr-insert-document dom)))))
1221 ;; Gemini page retrieval
1223 (defvar elpher-gemini-redirect-chain)
1225 (defun elpher-get-gemini-response (address renderer)
1226 "Get response string from gemini server at ADDRESS and render using RENDERER."
1227 (elpher-get-host-response address 1965
1228 (concat (elpher-address-to-url address) "\r\n")
1229 (lambda (response-string)
1230 (elpher-process-gemini-response response-string renderer))
1233 (defun elpher-parse-gemini-response (response)
1234 "Parse the RESPONSE string and return a list of components.
1235 The list is of the form (code meta body). A response of nil implies
1236 that the response was malformed."
1237 (let ((header-end-idx (string-match "\r\n" response)))
1239 (let ((header (string-trim (substring response 0 header-end-idx)))
1240 (body (substring response (+ header-end-idx 2))))
1241 (if (>= (length header) 2)
1242 (let ((code (substring header 0 2))
1243 (meta (string-trim (substring header 2))))
1244 (list code meta body))
1245 (error "Malformed response: No response status found in header %s" header)))
1246 (error "Malformed response: No CRLF-delimited header found in response %s" response))))
1248 (defun elpher-process-gemini-response (response-string renderer)
1249 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
1250 (let ((response-components (elpher-parse-gemini-response response-string)))
1251 (let ((response-code (elt response-components 0))
1252 (response-meta (elt response-components 1))
1253 (response-body (elt response-components 2)))
1254 (pcase (elt response-code 0)
1255 (?1 ; Input required
1256 (elpher-with-clean-buffer
1257 (insert "Gemini server is requesting input."))
1258 (let* ((query-string
1259 (if (eq (elt response-code 1) ?1)
1260 (read-passwd (concat response-meta ": "))
1261 (read-string (concat response-meta ": "))))
1262 (query-address (seq-copy (elpher-page-address elpher-current-page)))
1263 (old-fname (url-filename query-address)))
1264 (setf (url-filename query-address)
1265 (concat old-fname "?" (url-build-query-string `((,query-string)))))
1266 (elpher-get-gemini-response query-address renderer)))
1267 (?2 ; Normal response
1268 (funcall renderer response-body response-meta))
1270 (message "Following redirect to %s" response-meta)
1271 (if (>= (length elpher-gemini-redirect-chain) 5)
1272 (error "More than 5 consecutive redirects followed"))
1273 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
1274 (if (member redirect-address elpher-gemini-redirect-chain)
1275 (error "Redirect loop detected"))
1276 (if (not (string= (elpher-address-protocol redirect-address)
1278 (error "Server tried to automatically redirect to non-gemini URL: %s"
1280 (elpher-page-set-address elpher-current-page redirect-address)
1281 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
1282 (elpher-get-gemini-response redirect-address renderer)))
1283 (?4 ; Temporary failure
1284 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
1285 response-code response-meta))
1286 (?5 ; Permanent failure
1287 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
1288 response-code response-meta))
1289 (?6 ; Client certificate required
1290 (elpher-with-clean-buffer
1291 (if elpher-client-certificate
1292 (insert "Gemini server does not recognise the provided TLS certificate:\n\n")
1293 (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
1295 (elpher-gemini-insert-text response-meta))
1296 (let ((chosen-certificate (elpher-choose-client-certificate)))
1297 (unless chosen-certificate
1298 (error "Gemini server requires a client certificate and none was provided"))
1299 (setq elpher-client-certificate chosen-certificate))
1300 (elpher-with-clean-buffer)
1301 (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer))
1303 (error "Gemini server response unknown: %s %s"
1304 response-code response-meta))))))
1306 (defun elpher--read-answer-polyfill (question answers)
1307 "Polyfill for `read-answer' in Emacs 26.1.
1308 QUESTION is a string containing a question, and ANSWERS
1309 is a list of possible answers."
1310 (completing-read question (mapcar 'identity answers)))
1312 (if (fboundp 'read-answer)
1313 (defalias 'elpher-read-answer 'read-answer)
1314 (defalias 'elpher-read-answer 'elpher--read-answer-polyfill))
1316 (defun elpher-choose-client-certificate ()
1317 "Prompt for a client certificate to use to establish a TLS connection."
1318 (let* ((read-answer-short t))
1319 (pcase (read-answer "What do you want to do? "
1321 "generate and use throw-away certificate")
1323 "generate new or use existing persistent certificate")
1325 "stop immediately")))
1327 (setq elpher-client-certificate (elpher-generate-throwaway-certificate)))
1329 (let* ((existing-certificates (elpher-list-existing-certificates))
1330 (file-base (completing-read
1331 "Nickname for new or existing certificate (autocompletes, empty response aborts): "
1332 existing-certificates)))
1333 (if (string-empty-p (string-trim file-base))
1335 (if (member file-base existing-certificates)
1336 (setq elpher-client-certificate
1337 (elpher-get-existing-certificate file-base))
1338 (pcase (read-answer "Generate new certificate or install externally-generated one? "
1340 "generate new certificate")
1342 "install existing certificate")
1344 "stop immediately")))
1346 (let ((common-name (read-string "Common Name field for new certificate: "
1348 (message "New key and self-signed certificate written to %s"
1349 elpher-certificate-directory)
1350 (elpher-generate-persistent-certificate file-base common-name)))
1352 (let* ((cert-file (read-file-name "Certificate file: " nil nil t))
1353 (key-file (read-file-name "Key file: " nil nil t)))
1354 (message "Key and certificate installed in %s for future use"
1355 elpher-certificate-directory)
1356 (elpher-install-and-use-existing-certificate key-file
1362 (defun elpher-get-gemini-page (renderer)
1363 "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
1364 (let* ((address (elpher-page-address elpher-current-page))
1365 (content (elpher-get-cached-content address)))
1366 (condition-case the-error
1367 (if (and content (funcall renderer nil))
1368 (elpher-with-clean-buffer
1370 (elpher-restore-pos))
1371 (elpher-with-clean-buffer
1372 (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
1373 (setq elpher-gemini-redirect-chain nil)
1374 (elpher-get-gemini-response address renderer))
1376 (elpher-network-error address the-error)))))
1378 (defun elpher-render-gemini (body &optional mime-type-string)
1379 "Render gemini response BODY with rendering MIME-TYPE-STRING."
1382 (let* ((mime-type-string* (if (or (not mime-type-string)
1383 (string-empty-p mime-type-string))
1384 "text/gemini; charset=utf-8"
1386 (mime-type-split (split-string mime-type-string* ";" t))
1387 (mime-type (string-trim (car mime-type-split)))
1388 (parameters (mapcar (lambda (s)
1389 (let ((key-val (split-string s "=")))
1390 (list (downcase (string-trim (car key-val)))
1391 (downcase (string-trim (cadr key-val))))))
1392 (cdr mime-type-split))))
1393 (when (string-prefix-p "text/" mime-type)
1394 (setq body (decode-coding-string
1396 (if (assoc "charset" parameters)
1397 (intern (cadr (assoc "charset" parameters)))
1399 (setq body (replace-regexp-in-string "\r" "" body)))
1401 ((or "text/gemini" "")
1402 (elpher-render-gemini-map body parameters))
1404 (elpher-render-html body))
1405 ((pred (string-prefix-p "text/"))
1406 (elpher-render-gemini-plain-text body parameters))
1407 ((pred (string-prefix-p "image/"))
1408 (elpher-render-image body))
1410 (elpher-render-download body))))))
1412 (defun elpher-gemini-get-link-url (link-line)
1413 "Extract the url portion of LINK-LINE, a gemini map file link line.
1414 Returns nil in the event that the contents of the line following the
1415 => prefix are empty."
1416 (let ((l (split-string (substring link-line 2))))
1418 (string-trim (elt l 0))
1421 (defun elpher-gemini-get-link-display-string (link-line)
1422 "Extract the display string portion of LINK-LINE, a gemini map file link line.
1423 Returns the url portion in the event that the display-string portion is empty."
1424 (let* ((rest (string-trim (elt (split-string link-line "=>") 1)))
1425 (idx (string-match "[ \t]" rest)))
1426 (string-trim (if idx
1427 (substring rest (+ idx 1))
1430 (defun elpher-collapse-dot-sequences (filename)
1431 "Collapse dot sequences in FILENAME.
1432 For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
1433 (let* ((path (split-string filename "/"))
1434 (path-reversed-normalized
1435 (seq-reduce (lambda (a b)
1436 (cond ((and a (equal b "..") (cdr a)))
1437 ((and (not a) (equal b "..")) a) ;leading .. are dropped
1441 (string-join (reverse path-reversed-normalized) "/")))
1443 (defun elpher-address-from-gemini-url (url)
1444 "Extract address from URL with defaults as per gemini map files.
1445 While there's obviously some redundancy here between this function and
1446 `elpher-address-from-url', gemini map file URLs require enough special
1447 treatment that a separate function is warranted."
1448 (let ((address (url-generic-parse-url url))
1449 (current-address (elpher-page-address elpher-current-page)))
1450 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
1451 (setf (url-fullness address) t)
1452 (if (url-host address) ;if there is an explicit host, filenames are absolute
1453 (if (string-empty-p (url-filename address))
1454 (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
1455 (setf (url-host address) (url-host current-address))
1456 (setf (url-port address) (url-port current-address))
1457 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
1458 (setf (url-filename address)
1459 (concat (file-name-directory (url-filename current-address))
1460 (url-filename address)))))
1461 (unless (url-type address)
1462 (setf (url-type address) "gemini"))
1463 (when (equal (url-type address) "gemini")
1464 (setf (url-filename address)
1465 (elpher-collapse-dot-sequences (url-filename address)))))
1466 (elpher-remove-redundant-ports address)))
1468 (defun elpher-gemini-insert-link (link-line)
1469 "Insert link described by LINK-LINE into a text/gemini document."
1470 (let* ((url (elpher-gemini-get-link-url link-line))
1471 (display-string (elpher-gemini-get-link-display-string link-line))
1472 (address (elpher-address-from-gemini-url url))
1473 (type (if address (elpher-address-type address) nil))
1474 (type-map-entry (cdr (assoc type elpher-type-map))))
1475 (when display-string
1476 (insert elpher-gemini-link-string)
1478 (let* ((face (elt type-map-entry 3))
1479 (filtered-display-string (elpher-color-filter-apply display-string))
1480 (page (elpher-make-page filtered-display-string address)))
1481 (insert-text-button filtered-display-string
1484 'action #'elpher-click-link
1486 'help-echo #'elpher--page-button-help))
1487 (insert (propertize display-string 'face 'elpher-unknown)))
1490 (defvar elpher--gemini-page-headings nil
1491 "List of headings on the page.")
1493 (defun elpher-gemini-insert-header (header-line)
1494 "Insert header described by HEADER-LINE into a text/gemini document.
1495 The gemini map file line describing the header is given
1497 (when (string-match "^\\(#+\\)[ \t]*" header-line)
1498 (let* ((level (length (match-string 1 header-line)))
1499 (header (substring header-line (match-end 0)))
1501 (1 'elpher-gemini-heading1)
1502 (2 'elpher-gemini-heading2)
1503 (3 'elpher-gemini-heading3)
1505 (fill-column (if (display-graphic-p)
1507 (font-get (font-spec :name (face-font 'default)) :size))
1508 (font-get (font-spec :name (face-font face)) :size)) fill-column)))
1509 (setq elpher--gemini-page-headings (cons (cons header (point))
1510 elpher--gemini-page-headings))
1511 (unless (display-graphic-p)
1512 (insert (make-string level ?#) " "))
1513 (insert (format "%s\n" (propertize header 'face face))))))
1515 (defun elpher-gemini-insert-text (text-line)
1516 "Insert a plain non-preformatted TEXT-LINE into a text/gemini document.
1517 This function uses Emacs' auto-fill to wrap text sensibly to a maximum
1518 width defined by `elpher-gemini-max-fill-width'."
1519 (string-match "\\(^[ \t]*\\)\\(\\*[ \t]+\\|>[ \t]*\\)?" text-line)
1520 (let* ((line-prefix (match-string 2 text-line))
1521 (processed-text-line
1523 (cond ((string-prefix-p "*" line-prefix)
1525 (replace-regexp-in-string "\\*"
1526 elpher-gemini-bullet-string
1527 (match-string 0 text-line))
1528 (substring text-line (match-end 0))))
1529 ((string-prefix-p ">" line-prefix)
1530 (propertize text-line 'face 'elpher-gemini-quoted))
1533 (adaptive-fill-mode t)
1534 ;; fill-prefix is important for adaptive-fill-mode: without
1535 ;; it, multi-line list items are not indented correct
1536 (fill-prefix (if (match-string 2 text-line)
1537 (replace-regexp-in-string "[>\*]" " " (match-string 0 text-line))
1539 (insert (elpher-process-text-for-display processed-text-line))
1542 (defun elpher-render-gemini-map (data _parameters)
1543 "Render DATA as a gemini map file, PARAMETERS is currently unused."
1544 (elpher-with-clean-buffer
1545 (setq elpher--gemini-page-headings nil)
1546 (let ((preformatted nil))
1548 (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))
1549 (dolist (line (split-string data "\n"))
1551 ((string-prefix-p "```" line) (setq preformatted (not preformatted)))
1552 (preformatted (insert (elpher-process-text-for-display
1553 (propertize line 'face 'elpher-gemini-preformatted))
1555 ((string-prefix-p "=>" line)
1556 (elpher-gemini-insert-link line))
1557 ((string-prefix-p "#" line) (elpher-gemini-insert-header line))
1558 (t (elpher-gemini-insert-text line)))))
1559 (setq elpher--gemini-page-headings (nreverse elpher--gemini-page-headings))
1560 (elpher-cache-content
1561 (elpher-page-address elpher-current-page)
1564 (defun elpher-render-gemini-plain-text (data _parameters)
1565 "Render DATA as plain text file. PARAMETERS is currently unused."
1566 (elpher-with-clean-buffer
1567 (insert (elpher-process-text-for-display data))
1568 (elpher-cache-content
1569 (elpher-page-address elpher-current-page)
1573 ;; Finger page connection
1575 (defun elpher-get-finger-page (renderer)
1576 "Opens a finger connection to the current page address.
1577 The result is rendered using RENDERER."
1578 (let* ((address (elpher-page-address elpher-current-page))
1579 (content (elpher-get-cached-content address)))
1580 (if (and content (funcall renderer nil))
1581 (elpher-with-clean-buffer
1583 (elpher-restore-pos))
1584 (elpher-with-clean-buffer
1585 (insert "LOADING... (use 'u' to cancel)\n"))
1586 (condition-case the-error
1587 (let* ((kill-buffer-query-functions nil)
1588 (user (let ((filename (elpher-address-filename address)))
1589 (if (> (length filename) 1)
1590 (substring filename 1)
1591 (elpher-address-user address)))))
1592 (elpher-get-host-response address 79
1593 (concat user "\r\n")
1596 (elpher-network-error address the-error))))))
1599 ;; Telnet page connection
1601 (defun elpher-get-telnet-page (renderer)
1602 "Opens a telnet connection to the current page address (RENDERER must be nil)."
1604 (elpher-visit-previous-page)
1605 (error "Command not supported for telnet URLs"))
1606 (let* ((address (elpher-page-address elpher-current-page))
1607 (host (elpher-address-host address))
1608 (port (elpher-address-port address)))
1609 (elpher-visit-previous-page)
1615 ;; Other URL page opening
1617 (defun elpher-get-other-url-page (renderer)
1618 "Getter which attempts to open the URL specified by the current page (RENDERER must be nil)."
1620 (elpher-visit-previous-page)
1621 (error "Command not supported for general URLs"))
1622 (let* ((address (elpher-page-address elpher-current-page))
1623 (url (elpher-address-to-url address)))
1625 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1626 (message "Opening URL...")
1627 (if elpher-open-urls-with-eww
1629 (browse-url url)))))
1632 ;; Start page retrieval
1634 (defun elpher-get-start-page (renderer)
1635 "Getter which displays the start page (RENDERER must be nil)."
1637 (elpher-visit-previous-page)
1638 (error "Command not supported for start page"))
1639 (elpher-with-clean-buffer
1640 (insert " --------------------------------------------\n"
1641 " Elpher Gopher and Gemini Client \n"
1642 " version " elpher-version "\n"
1643 " --------------------------------------------\n"
1645 "Default bindings:\n"
1647 " - TAB/Shift-TAB: next/prev item on current page\n"
1648 " - RET/mouse-1: open item under cursor\n"
1649 " - m: select an item on current page by name (autocompletes)\n"
1650 " - u/mouse-3/U: return to previous page or to the start page\n"
1651 " - g: go to a particular address (gopher, gemini, finger)\n"
1652 " - o/O: open a different address selector or the root menu of the current server\n"
1653 " - d/D: download item under cursor or current page\n"
1654 " - i/I: info on item under cursor or current page\n"
1655 " - c/C: copy URL representation of item under cursor or current page\n"
1656 " - a/A: bookmark the item under cursor or current page\n"
1657 " - B: list all bookmarks\n"
1658 " - s/S: show current history stack or all previously visted pages\n"
1659 " - r: redraw current page (using cached contents if available)\n"
1660 " - R: reload current page (regenerates cache)\n"
1661 " - !: set character coding system for gopher (default is to autodetect)\n"
1662 " - T: toggle TLS gopher mode\n"
1663 " - F: forget/discard current TLS client certificate\n"
1664 " - .: display the raw server response for the current page\n"
1666 "Start your exploration of gopher space and gemini:\n")
1667 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1668 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1669 (elpher-insert-index-record "Project Gemini home page"
1670 (elpher-address-from-url "gemini://gemini.circumlunar.space/"))
1672 "Alternatively, select a search engine and enter some search terms:\n")
1673 (elpher-insert-index-record "Gopher Search Engine (Veronica-2)"
1674 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1675 (elpher-insert-index-record "Gemini Search Engine (geminispace.info)"
1676 (elpher-address-from-url "gemini://geminispace.info/search"))
1678 "Your bookmarks are stored in your ")
1679 (let ((help-string "RET,mouse-1: Open bookmark list"))
1680 (insert-text-button "bookmark list"
1684 (call-interactively #'elpher-show-bookmarks))
1686 'help-echo help-string))
1689 "(Bookmarks from legacy elpher-bookmarks files will be automatically imported.)\n"
1692 "The gopher home of the Elpher project is here:\n")
1693 (elpher-insert-index-record "The Elpher Project Page"
1694 (elpher-make-gopher-address ?1
1698 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1700 "The following info documentation is available:\n"
1702 (insert-text-button "Elpher Manual"
1708 'help-echo help-string)
1710 (insert-text-button "Changes introduced by the latest release"
1714 (info "(elpher)News"))
1716 'help-echo help-string))
1719 (concat "(These documents should be available if you have installed Elpher \n"
1720 " using MELPA. Otherwise you may have to install the manual yourself.)\n")
1722 (elpher-restore-pos)))
1724 ;; History page retrieval
1726 (defun elpher-show-history ()
1727 "Show the current contents of elpher's history stack.
1728 Use \\[elpher-show-visited-pages] to see the entire history.
1729 This is rendered using `elpher-get-history-page' via `elpher-type-map'."
1732 (elpher-make-page "Current History Stack"
1733 (elpher-make-special-address 'history))))
1735 (defun elpher-show-visited-pages ()
1736 "Show the all the pages you've visited using Elpher.
1737 Use \\[elpher-show-history] to see just the current history stack.
1738 This is rendered using `elpher-get-visited-pages-page' via `elpher-type-map'."
1741 (elpher-make-page "Elpher Visted Pages"
1742 (elpher-make-special-address 'visited-pages))))
1744 (defun elpher-get-history-page (renderer)
1745 "Getter which displays the history page (RENDERER must be nil)."
1747 (elpher-visit-previous-page)
1748 (error "Command not supported for history page"))
1749 (elpher-display-history-links elpher-history "Current history stack"))
1751 (defun elpher-get-visited-pages-page (renderer)
1752 "Getter which displays the list of visited pages (RENDERER must be nil)."
1754 (elpher-visit-previous-page)
1755 (error "Command not supported for history page"))
1756 (elpher-display-history-links
1757 (seq-filter (lambda (page)
1758 (not (elpher-address-special-p (elpher-page-address page))))
1759 elpher-visited-pages)
1760 "All visited pages"))
1762 (defun elpher-display-history-links (pages title)
1763 "Show all PAGES in an Elpher buffer with a given TITLE."
1764 (let* ((title-line (concat " ---- " title " ----"))
1765 (footer-line (make-string (length title-line) ?-)))
1766 (elpher-with-clean-buffer
1767 (insert title-line "\n\n")
1769 (dolist (page pages)
1771 (let ((display-string (elpher-page-display-string page))
1772 (address (elpher-page-address page)))
1773 (elpher-insert-index-record display-string address))))
1774 (insert "No history items found.\n"))
1775 (insert "\n " footer-line "\n"
1776 "Select an entry or press 'u' to return to the previous page.")
1777 (elpher-restore-pos))))
1782 ;; This code allows Elpher to use the standard Emacs bookmarks: `C-x r
1783 ;; m' to add a bookmark, `C-x r l' to list bookmarks (which is where
1784 ;; you can anotate bookmarks!), `C-x r b' to jump to a bookmark, and
1785 ;; so on. See the Bookmarks section in the Emacs info manual for more.
1787 (defvar elpher-bookmark-link nil
1788 "Prefer bookmarking a link or the current page.
1789 Bind this variable dynamically, or set it to t.
1790 If you set it to t, the commands \\[bookmark-set-no-overwrite]
1791 and \\[elpher-set-bookmark-no-overwrite] do the same thing.")
1793 (defun elpher-bookmark-make-record ()
1794 "Return a bookmark record.
1795 If `elpher-bookmark-link' is non-nil and point is on a link button,
1796 return a bookmark record for that link. Otherwise, return a bookmark
1797 record for the current elpher page."
1798 (let* ((button (and elpher-bookmark-link (button-at (point))))
1800 (button-get button 'elpher-page)
1801 elpher-current-page))
1802 (address (elpher-page-address page))
1803 (url (elpher-address-to-url address))
1804 (display-string (elpher-page-display-string page))
1805 (pos (if button nil (point))))
1806 (if (elpher-address-special-p address)
1807 (error "Cannot bookmark %s" display-string)
1809 (defaults . (,display-string))
1812 (handler . elpher-bookmark-jump)))))
1815 (defun elpher-bookmark-jump (bookmark)
1816 "Handler used to open a bookmark using elpher.
1817 The argument BOOKMARK is a bookmark record passed to the function.
1818 This handler is responsible for loading the bookmark in some buffer,
1819 then making that buffer the current buffer. It should not switch
1821 (let* ((url (cdr (assq 'location bookmark)))
1822 (cleaned-url (string-trim url))
1823 (address (elpher-address-from-url cleaned-url))
1824 (page (elpher-make-page cleaned-url address)))
1825 (elpher-with-clean-buffer
1826 (elpher-visit-page page))
1827 (set-buffer (get-buffer elpher-buffer-name))
1830 (defun elpher-bookmark-link ()
1831 "Bookmark the link at point.
1832 To bookmark the current page, use \\[elpher-bookmark-current]."
1834 (let ((elpher-bookmark-link t))
1835 (bookmark-set-no-overwrite)))
1837 (defun elpher-bookmark-current ()
1838 "Bookmark the current page.
1839 To bookmark the link at point use \\[elpher-bookmark-link]."
1841 (call-interactively #'bookmark-set-no-overwrite))
1843 (defun elpher-bookmark-import (file)
1844 "Import legacy Elpher bookmarks file FILE into Emacs bookmarks."
1845 (interactive (list (if (and (boundp 'elpher-bookmarks-file)
1846 (file-readable-p elpher-bookmarks-file))
1847 elpher-bookmarks-file
1848 (read-file-name "Old Elpher bookmarks: "
1849 user-emacs-directory nil t
1850 "elpher-bookmarks"))))
1851 (dolist (bookmark (with-temp-buffer
1852 (insert-file-contents file)
1853 (read (current-buffer))))
1854 (let* ((display-string (car bookmark))
1855 (url (cadr bookmark))
1856 (record `(,display-string
1858 (handler . elpher-bookmark-jump))))
1859 (bookmark-store display-string (cdr record) t)))
1862 (defun elpher-get-bookmarks-page (renderer)
1863 "Getter which displays the history page (RENDERER must be nil)."
1865 (elpher-visit-previous-page)
1866 (error "Command not supported for bookmarks page"))
1867 (elpher-with-clean-buffer
1868 (insert " ---- Elpher Bookmarks ---- \n\n")
1869 (bookmark-maybe-load-default-file)
1870 (dolist (bookmark (bookmark-maybe-sort-alist))
1871 (when (eq #'elpher-bookmark-jump (alist-get 'handler (cdr bookmark)))
1872 (let* ((name (car bookmark))
1873 (url (alist-get 'location (cdr bookmark)))
1874 (address (elpher-address-from-url url)))
1875 (elpher-insert-index-record name address))))
1876 (when (<= (line-number-at-pos) 3)
1877 (insert "No bookmarked pages found.\n"))
1878 (insert "\n --------------------------\n\n"
1879 "Select an entry or press 'u' to return to the previous page.\n\n"
1880 "Bookmarks can be renamed or deleted via the ")
1881 (insert-text-button "Emacs bookmark menu"
1884 (call-interactively #'bookmark-bmenu-list))
1886 'help-echo "RET,mouse-1: open Emacs bookmark menu")
1887 (insert (substitute-command-keys
1888 ",\nwhich can also be opened from anywhere using '\\[bookmark-bmenu-list]'."))
1889 (elpher-restore-pos)))
1891 (defun elpher-show-bookmarks ()
1892 "Display the current list of elpher bookmarks.
1893 This will also check for a legacy bookmark file and offer to import it."
1895 (let ((old-bookmarks-file (or (and (boundp 'elpher-bookmarks-file)
1896 elpher-bookmarks-file)
1897 (locate-user-emacs-file "elpher-bookmarks"))))
1898 (when (and (file-readable-p old-bookmarks-file)
1899 (y-or-n-p (concat "Legacy elpher-bookmarks file \""
1901 "\" found. Import now?")))
1902 (elpher-bookmark-import old-bookmarks-file)
1903 (rename-file old-bookmarks-file (concat old-bookmarks-file "-legacy"))))
1904 (if elpher-use-emacs-bookmark-menu
1905 (call-interactively #'bookmark-bmenu-list)
1907 (elpher-make-page "Elpher Bookmarks"
1908 (elpher-make-special-address 'bookmarks)))))
1916 (defun elpher-org-export-link (link description format protocol)
1917 "Export a LINK with DESCRIPTION for the given PROTOCOL and FORMAT.
1919 FORMAT is an Org export backend. DESCRIPTION may be nil. PROTOCOL may be one
1920 of gemini, gopher or finger."
1921 (let* ((url (if (equal protocol "elpher")
1922 (string-remove-prefix "elpher:" link)
1923 (format "%s:%s" protocol link)))
1924 (desc (or description url)))
1926 (`gemini (format "=> %s %s" url desc))
1927 (`html (format "<a href=\"%s\">%s</a>" url desc))
1928 (`latex (format "\\href{%s}{%s}" url desc))
1929 (_ (if (not description)
1931 (format "%s (%s)" desc url))))))
1933 (defun elpher-org-store-link ()
1934 "Store link to an `elpher' page in Org."
1935 (when (eq major-mode 'elpher-mode)
1936 (let* ((url (elpher-info-current))
1937 (desc (car elpher-current-page))
1939 ((string-prefix-p "gemini:" url) "gemini")
1940 ((string-prefix-p "gopher:" url) "gopher")
1941 ((string-prefix-p "finger:" url) "finger")
1943 (when (equal "elpher" protocol)
1944 ;; Weird link. Or special inner link?
1945 (setq url (concat "elpher:" url)))
1946 (org-link-store-props :type protocol :link url :description desc)
1949 (defun elpher-org-follow-link (link protocol)
1950 "Visit a LINK for the given PROTOCOL.
1952 PROTOCOL may be one of gemini, gopher or finger. This method also
1953 supports the old protocol elpher, where the link is self-contained."
1954 (let ((url (if (equal protocol "elpher")
1955 (string-remove-prefix "elpher:" link)
1956 (format "%s:%s" protocol link))))
1959 (defun elpher-org-mode-integration ()
1960 "Set up `elpher' integration for `org-mode'."
1961 (org-link-set-parameters
1963 :store #'elpher-org-store-link
1964 :export (lambda (link description format _plist)
1965 (elpher-org-export-link link description format "elpher"))
1966 :follow (lambda (link _arg) (elpher-org-follow-link link "elpher")))
1967 (org-link-set-parameters
1969 :export (lambda (link description format _plist)
1970 (elpher-org-export-link link description format "gemini"))
1971 :follow (lambda (link _arg) (elpher-org-follow-link link "gemini")))
1972 (org-link-set-parameters
1974 :export (lambda (link description format _plist)
1975 (elpher-org-export-link link description format "gopher"))
1976 :follow (lambda (link _arg) (elpher-org-follow-link link "gopher")))
1977 (org-link-set-parameters
1979 :export (lambda (link description format _plist)
1980 (elpher-org-export-link link description format "finger"))
1981 :follow (lambda (link _arg) (elpher-org-follow-link link "finger"))))
1983 (add-hook 'org-mode-hook #'elpher-org-mode-integration)
1988 (defun elpher-browse-url-elpher (url &rest _args)
1989 "Browse URL using Elpher. This function is used by `browse-url'."
1990 (interactive (browse-url-interactive-arg "Elpher URL: "))
1993 ;; Use elpher to open gopher, finger and gemini links
1994 ;; For recent version of `browse-url' package
1995 (if (boundp 'browse-url-default-handlers)
1997 'browse-url-default-handlers
1998 '("^\\(gopher\\|finger\\|gemini\\)://" . elpher-browse-url-elpher))
1999 ;; Patch `browse-url-browser-function' for older ones. The value of
2000 ;; that variable is `browse-url-default-browser' by default, so
2001 ;; that's the function that gets advised.
2002 (advice-add browse-url-browser-function :before-while
2003 (lambda (url &rest _args)
2004 "Handle gemini, gopher, and finger schemes using Elpher."
2005 (let ((scheme (downcase (car (split-string url ":" t)))))
2006 (if (member scheme '("gemini" "gopher" "finger"))
2007 ;; `elpher-go' always returns nil, which will stop the
2008 ;; advice chain here in a before-while
2010 ;; chain must continue, then return t.
2013 ;; Register "gemini://" as a URI scheme so `browse-url' does the right thing
2014 (with-eval-after-load 'thingatpt
2015 (add-to-list 'thing-at-point-uri-schemes "gemini://"))
2019 ;; Make mu4e aware of the gemini world
2020 (setq mu4e~view-beginning-of-url-regexp
2021 "\\(?:https?\\|gopher\\|finger\\|gemini\\)://\\|mailto:")
2025 ;; Let elpher handle gemini, gopher links in eww buffer.
2026 (setq eww-use-browse-url
2027 "\\`mailto:\\|\\(\\`gemini\\|\\`gopher\\|\\`finger\\)://")
2029 ;;; Interactive procedures
2032 (defun elpher-next-link ()
2033 "Move point to the next link on the current page."
2037 (defun elpher-prev-link ()
2038 "Move point to the previous link on the current page."
2040 (backward-button 1))
2042 (defun elpher-follow-current-link ()
2043 "Open the link or url at point."
2048 (defun elpher-go (host-or-url)
2049 "Go to a particular gopher site HOST-OR-URL.
2050 When run interactively HOST-OR-URL is read from the minibuffer."
2051 (interactive "sGopher or Gemini URL: ")
2052 (let* ((cleaned-host-or-url (string-trim host-or-url))
2053 (address (elpher-address-from-url cleaned-host-or-url))
2054 (page (elpher-make-page cleaned-host-or-url address)))
2055 (switch-to-buffer elpher-buffer-name)
2056 (elpher-with-clean-buffer
2057 (elpher-visit-page page))
2060 (defun elpher-go-current ()
2061 "Go to a particular site read from the minibuffer, initialized with the current URL."
2063 (let ((address (elpher-page-address elpher-current-page)))
2064 (let ((url (read-string "Gopher or Gemini URL: "
2065 (unless (elpher-address-special-p address)
2066 (elpher-address-to-url address)))))
2067 (elpher-visit-page (elpher-make-page url (elpher-address-from-url url))))))
2069 (defun elpher-redraw ()
2070 "Redraw current page."
2072 (elpher-visit-page elpher-current-page))
2074 (defun elpher-reload ()
2075 "Reload current page."
2077 (elpher-reload-current-page))
2079 (defun elpher-toggle-tls ()
2080 "Toggle TLS encryption mode for gopher."
2082 (setq elpher-use-tls (not elpher-use-tls))
2084 (if (gnutls-available-p)
2085 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
2086 (setq elpher-use-tls nil)
2087 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
2088 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
2090 (defun elpher-view-raw ()
2091 "View raw server response for current page."
2093 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
2094 (error "This page was not generated by a server")
2095 (elpher-visit-page elpher-current-page
2096 #'elpher-render-raw)))
2098 (defun elpher-back ()
2099 "Go to previous site."
2101 (elpher-visit-previous-page))
2103 (defun elpher-back-to-start ()
2104 "Go all the way back to the start page."
2106 (setq-local elpher-current-page nil)
2107 (setq-local elpher-history nil)
2108 (elpher-visit-page (elpher-make-start-page)))
2110 (defun elpher-download ()
2111 "Download the link at point."
2113 (let ((button (button-at (point))))
2115 (let ((page (button-get button 'elpher-page)))
2116 (if (elpher-address-special-p (elpher-page-address page))
2117 (error "Cannot download %s"
2118 (elpher-page-display-string page))
2119 (elpher-visit-page (button-get button 'elpher-page)
2120 #'elpher-render-download)))
2121 (error "No link selected"))))
2123 (defun elpher-download-current ()
2124 "Download the current page."
2126 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
2127 (error "Cannot download %s"
2128 (elpher-page-display-string elpher-current-page))
2129 (elpher-visit-page (elpher-make-page
2130 (elpher-page-display-string elpher-current-page)
2131 (elpher-page-address elpher-current-page))
2132 #'elpher-render-download
2135 (defun elpher--build-link-map ()
2136 "Build alist mapping link names to destination pages in current buffer."
2137 (let ((link-map nil)
2138 (b (next-button (point-min) t)))
2140 (push (cons (button-label b) b) link-map)
2141 (setq b (next-button (button-start b))))
2144 (defun elpher-jump ()
2145 "Select a directory entry by name. Similar to the info browser (m)enu command."
2147 (let* ((link-map (elpher--build-link-map)))
2149 (let ((key (let ((completion-ignore-case t))
2150 (completing-read "Directory item/link: "
2152 (if (and key (> (length key) 0))
2153 (let ((b (cdr (assoc key link-map))))
2154 (goto-char (button-start b))
2155 (button-activate b)))))))
2157 (defun elpher-root-dir ()
2158 "Visit root of current server."
2160 (let ((address (elpher-page-address elpher-current-page)))
2161 (if (not (elpher-address-special-p address))
2162 (if (or (member (url-filename address) '("/" ""))
2163 (and (elpher-address-gopher-p address)
2164 (= (length (elpher-gopher-address-selector address)) 0)))
2165 (error "Already at root directory of current server")
2166 (let ((address-copy (elpher-address-from-url
2167 (elpher-address-to-url address))))
2168 (setf (url-filename address-copy) "")
2169 (elpher-go (elpher-address-to-url address-copy))))
2170 (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
2172 (defun elpher-info-page (page)
2173 "Display information on PAGE."
2174 (let ((display-string (elpher-page-display-string page))
2175 (address (elpher-page-address page)))
2176 (if (elpher-address-special-p address)
2177 (message "Special page: %s" display-string)
2178 (message "%s" (elpher-address-to-url address)))))
2180 (defun elpher-info-link ()
2181 "Display information on page corresponding to link at point."
2183 (let ((button (button-at (point))))
2185 (elpher-info-page (button-get button 'elpher-page))
2186 (error "No item selected"))))
2188 (defun elpher-info-current ()
2189 "Display information on current page."
2191 (elpher-info-page elpher-current-page))
2193 (defun elpher-copy-page-url (page)
2194 "Copy URL representation of address of PAGE to `kill-ring'."
2195 (let ((address (elpher-page-address page)))
2196 (if (elpher-address-special-p address)
2197 (error (format "Cannot represent %s as URL" (elpher-page-display-string page)))
2198 (let ((url (elpher-address-to-url address)))
2199 (message "Copied \"%s\" to kill-ring/clipboard." url)
2202 (defun elpher-copy-link-url ()
2203 "Copy URL of item at point to `kill-ring'."
2205 (let ((button (button-at (point))))
2207 (elpher-copy-page-url (button-get button 'elpher-page))
2208 (error "No item selected"))))
2210 (defun elpher-copy-current-url ()
2211 "Copy URL of current page to `kill-ring'."
2213 (elpher-copy-page-url elpher-current-page))
2215 (defun elpher-set-gopher-coding-system ()
2216 "Specify an explicit character coding system for gopher selectors."
2218 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
2219 (setq elpher-user-coding-system system)
2221 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
2222 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
2228 (defvar elpher-mode-map
2229 (let ((map (make-sparse-keymap)))
2230 (define-key map (kbd "TAB") 'elpher-next-link)
2231 (define-key map (kbd "<backtab>") 'elpher-prev-link)
2232 (define-key map (kbd "C-M-i") 'elpher-prev-link)
2233 (define-key map (kbd "u") 'elpher-back)
2234 (define-key map (kbd "-") 'elpher-back)
2235 (define-key map (kbd "^") 'elpher-back)
2236 (define-key map [mouse-3] 'elpher-back)
2237 (define-key map (kbd "U") 'elpher-back-to-start)
2238 (define-key map (kbd "g") 'elpher-go)
2239 (define-key map (kbd "o") 'elpher-go-current)
2240 (define-key map (kbd "O") 'elpher-root-dir)
2241 (define-key map (kbd "s") 'elpher-show-history)
2242 (define-key map (kbd "S") 'elpher-show-visited-pages)
2243 (define-key map (kbd "r") 'elpher-redraw)
2244 (define-key map (kbd "R") 'elpher-reload)
2245 (define-key map (kbd "T") 'elpher-toggle-tls)
2246 (define-key map (kbd ".") 'elpher-view-raw)
2247 (define-key map (kbd "d") 'elpher-download)
2248 (define-key map (kbd "D") 'elpher-download-current)
2249 (define-key map (kbd "m") 'elpher-jump)
2250 (define-key map (kbd "i") 'elpher-info-link)
2251 (define-key map (kbd "I") 'elpher-info-current)
2252 (define-key map (kbd "c") 'elpher-copy-link-url)
2253 (define-key map (kbd "C") 'elpher-copy-current-url)
2254 (define-key map (kbd "a") 'elpher-bookmark-link)
2255 (define-key map (kbd "A") 'elpher-bookmark-current)
2256 (define-key map (kbd "B") 'elpher-show-bookmarks)
2257 (define-key map (kbd "!") 'elpher-set-gopher-coding-system)
2258 (define-key map (kbd "F") 'elpher-forget-current-certificate)
2259 (when (fboundp 'evil-define-key*)
2262 (kbd "TAB") 'elpher-next-link
2263 (kbd "C-") 'elpher-follow-current-link
2264 (kbd "C-t") 'elpher-back
2265 (kbd "u") 'elpher-back
2266 (kbd "-") 'elpher-back
2267 (kbd "^") 'elpher-back
2268 [mouse-3] 'elpher-back
2269 (kbd "U") 'elpher-back-to-start
2270 (kbd "g") 'elpher-go
2271 (kbd "o") 'elpher-go-current
2272 (kbd "O") 'elpher-root-dir
2273 (kbd "s") 'elpher-show-history
2274 (kbd "S") 'elpher-show-visited-pages
2275 (kbd "r") 'elpher-redraw
2276 (kbd "R") 'elpher-reload
2277 (kbd "T") 'elpher-toggle-tls
2278 (kbd ".") 'elpher-view-raw
2279 (kbd "d") 'elpher-download
2280 (kbd "D") 'elpher-download-current
2281 (kbd "m") 'elpher-jump
2282 (kbd "i") 'elpher-info-link
2283 (kbd "I") 'elpher-info-current
2284 (kbd "c") 'elpher-copy-link-url
2285 (kbd "C") 'elpher-copy-current-url
2286 (kbd "a") 'elpher-bookmark-link
2287 (kbd "A") 'elpher-bookmark-current
2288 (kbd "B") 'elpher-show-bookmarks
2289 (kbd "!") 'elpher-set-gopher-coding-system
2290 (kbd "F") 'elpher-forget-current-certificate))
2292 "Keymap for gopher client.")
2294 (define-derived-mode elpher-mode special-mode "elpher"
2295 "Major mode for elpher, an elisp gopher client.
2297 This mode is automatically enabled by the interactive
2298 functions which initialize the client, namely
2299 `elpher', and `elpher-go'."
2300 (setq-local elpher--gemini-page-headings nil)
2301 (setq-local elpher-current-page nil)
2302 (setq-local elpher-history nil)
2303 (setq-local elpher-buffer-name (buffer-name))
2304 (setq-local bookmark-make-record-function #'elpher-bookmark-make-record)
2305 (setq-local imenu-create-index-function (lambda () elpher--gemini-page-headings))
2306 (setq-local xterm-color-preserve-properties t))
2308 (when (fboundp 'evil-set-initial-state)
2309 (evil-set-initial-state 'elpher-mode 'motion))
2312 ;;; Main start procedure
2316 (defun elpher (&optional arg)
2317 "Start elpher with default landing page.
2318 The buffer used for Elpher sessions is determined by the value of
2319 ‘elpher-buffer-name’. If there is already an Elpher session active in
2320 that buffer, Emacs will simply switch to it. Otherwise, a new session
2321 will begin. A numeric prefix ARG (as in ‘\\[universal-argument] 42
2322 \\[execute-extended-command] elpher RET’) switches to the session with
2323 that number, creating it if necessary. A non numeric prefix ARG means
2324 to create a new session. Returns the buffer selected (or created)."
2326 (let* ((name (default-value 'elpher-buffer-name))
2327 (buf (cond ((numberp arg)
2328 (get-buffer-create (format "%s<%d>" name arg)))
2330 (generate-new-buffer name))
2332 (get-buffer-create name)))))
2333 (pop-to-buffer-same-window buf)
2334 (unless (buffer-modified-p)
2336 (elpher-visit-page (elpher-make-start-page))
2337 "Started Elpher."))); Otherwise (elpher) evaluates to start page string.
2339 ;;; elpher.el ends here