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) 2020-2021 Alex Schroeder <alex@gnu.org>
9 ;; Copyright (C) 2020 Zhiwei Chen <chenzhiwei03@kuaishou.com>
10 ;; Copyright (C) 2020 condy0919 <condy0919@gmail.com>
11 ;; Copyright (C) 2020 Alexis <flexibeast@gmail.com>
12 ;; Copyright (C) 2020 Étienne Deparis <etienne@depar.is>
13 ;; Copyright (C) 2020 Simon Nicolussi <sinic@sinic.name>
14 ;; Copyright (C) 2020 Michel Alexandre Salim <michel@michel-slm.name>
15 ;; Copyright (C) 2020 Koushk Roy <kroy@twilio.com>
16 ;; Copyright (C) 2020 Vee <vee@vnsf.xyz>
17 ;; Copyright (C) 2020 Simon South <simon@simonsouth.net>
18 ;; Copyright (C) 2019-2021 Tim Vaughan <plugd@thelambdalab.xyz>
20 ;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
21 ;; Created: 11 April 2019
23 ;; Keywords: comm gopher
24 ;; Homepage: https://thelambdalab.xyz/elpher
25 ;; Package-Requires: ((emacs "27.1"))
27 ;; This file is not part of GNU Emacs.
29 ;; This program is free software: you can redistribute it and/or modify
30 ;; it under the terms of the GNU General Public License as published by
31 ;; the Free Software Foundation, either version 3 of the License, or
32 ;; (at your option) any later version.
34 ;; This program is distributed in the hope that it will be useful,
35 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
36 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
37 ;; GNU General Public License for more details.
39 ;; You should have received a copy of the GNU General Public License
40 ;; along with this file. If not, see <http://www.gnu.org/licenses/>.
44 ;; Elpher aims to provide a practical and friendly gopher and gemini
45 ;; client for GNU Emacs. It supports:
47 ;; - intuitive keyboard and mouse-driven browsing,
48 ;; - out-of-the-box compatibility with evil-mode,
49 ;; - clickable web and gopher links *in plain text*,
50 ;; - caching of visited sites,
51 ;; - pleasant and configurable colouring of Gopher directories,
52 ;; - direct visualisation of image files,
53 ;; - gopher connections using TLS encryption,
54 ;; - the fledgling Gemini protocol,
55 ;; - the greybeard Finger protocol.
57 ;; To launch Elpher, simply use 'M-x elpher'. This will open a start
58 ;; page containing information on key bindings and suggested starting
59 ;; points for your gopher exploration.
61 ;; Full instructions can be found in the Elpher info manual.
63 ;; Elpher is under active development. Any suggestions for
64 ;; improvements are welcome, and can be made on the official project
65 ;; page, gopher://thelambdalab.xyz/1/projects/elpher, or via the
66 ;; project mailing list at https://lists.sr.ht/~michel-slm/elpher.
88 (defconst elpher-version "3.0.0"
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 history) elpher-get-history-page nil "E" elpher-index)
114 ((special visited-pages) elpher-get-visited-pages-page nil "E" elpher-index))
115 "Association list from types to getters, renderers, margin codes and index faces.")
118 ;;; Declarations to avoid compiler warnings.
122 (declare-function ansi-color-filter-apply "ansi-color")
123 (declare-function ansi-color-apply "ansi-color")
124 (declare-function bookmark-store "bookmark")
125 (declare-function org-link-store-props "ol")
126 (declare-function org-link-set-parameters "ol")
127 (defvar ansi-color-context)
128 (defvar bookmark-make-record-function)
129 (defvar mu4e~view-beginning-of-url-regexp)
130 (defvar thing-at-point-uri-schemes))
133 ;;; Customization group
137 "A gopher and gemini client."
138 :group 'applications)
140 ;; General appearance and customizations
142 (defcustom elpher-open-urls-with-eww nil
143 "If non-nil, open URL selectors using eww.
144 Otherwise, use the system browser via the `browse-url' function."
147 (defcustom elpher-use-header t
148 "If non-nil, display current page information in buffer header."
151 (defcustom elpher-auto-disengage-TLS nil
152 "If non-nil, automatically disengage TLS following an unsuccessful connection.
153 While enabling this may seem convenient, it is also potentially
154 dangerous as it allows switching from an encrypted channel back to
155 plain text without user input."
158 (defcustom elpher-connection-timeout 5
159 "Specifies the number of seconds to wait for a network connection to time out."
162 (defcustom elpher-filter-ansi-from-text nil
163 "If non-nil, filter ANSI escape sequences from text.
164 The default behaviour is to use the ansi-color package to interpret these
168 (defcustom elpher-certificate-directory
169 (file-name-as-directory (locate-user-emacs-file "elpher-certificates"))
170 "Specify the name of the directory where client certificates will be stored.
171 These certificates may be used for establishing authenticated TLS connections."
174 (defcustom elpher-openssl-command "openssl"
175 "The command used to launch openssl when generating TLS client certificates."
178 (defcustom elpher-default-url-type "gopher"
179 "Default URL type (i.e. scheme) to assume if not explicitly given."
180 :type '(choice (const "gopher")
183 (defcustom elpher-gemini-TLS-cert-checks nil
184 "If non-nil, verify gemini server TLS certs using the default security level.
185 Otherwise, certificate verification is disabled.
187 This defaults to off because it is standard practice for Gemini servers
188 to use self-signed certificates, meaning that most servers provide what
189 EMACS considers to be an invalid certificate."
192 (defcustom elpher-gemini-max-fill-width 80
193 "Specify the maximum default width (in columns) of text/gemini documents.
194 The actual width used is the minimum of this value and the window width at
195 the time when the text is rendered."
198 (defcustom elpher-gemini-link-string "→ "
199 "Specify the string used to indicate links when rendering gemini maps.
203 (defcustom elpher-gemini-bullet-string "•"
204 "Specify the string used for bullets when rendering gemini maps."
207 (defcustom elpher-ipv4-always nil
208 "If non-nil, elpher will always use IPv4 to establish network connections.
209 This can be useful when browsing from a computer that supports IPv6, because
210 some servers which do not support IPv6 can take a long time to time-out."
213 (defcustom elpher-socks-always nil
214 "If non-nil, elpher will establish network connections over a SOCKS proxy.
215 Otherwise, the SOCKS proxy is only used for connections to onion services."
218 ;; Face customizations
220 (defgroup elpher-faces nil
221 "Elpher face customizations."
224 (defface elpher-index
225 '((t :inherit font-lock-keyword-face))
226 "Face used for directory type directory records.")
230 "Face used for text type directory records.")
233 '((t :inherit default))
234 "Face used for info type directory records.")
236 (defface elpher-image
237 '((t :inherit font-lock-string-face))
238 "Face used for image type directory records.")
240 (defface elpher-search
241 '((t :inherit warning))
242 "Face used for search type directory records.")
245 '((t :inherit font-lock-comment-face))
246 "Face used for html type directory records.")
248 (defface elpher-gemini
249 '((t :inherit font-lock-constant-face))
250 "Face used for Gemini type directory records.")
252 (defface elpher-other-url
253 '((t :inherit font-lock-comment-face))
254 "Face used for other URL type links records.")
256 (defface elpher-telnet
257 '((t :inherit font-lock-function-name-face))
258 "Face used for telnet type directory records.")
260 (defface elpher-binary
261 '((t :inherit font-lock-doc-face))
262 "Face used for binary type directory records.")
264 (defface elpher-unknown
265 '((t :inherit error))
266 "Face used for directory records with unknown/unsupported types.")
268 (defface elpher-margin-key
270 "Face used for directory margin key.")
272 (defface elpher-margin-brackets
273 '((t :inherit shadow))
274 "Face used for brackets around directory margin key.")
276 (defface elpher-gemini-heading1
277 '((t :inherit bold :height 1.8))
278 "Face used for gemini heading level 1.")
280 (defface elpher-gemini-heading2
281 '((t :inherit bold :height 1.5))
282 "Face used for gemini heading level 2.")
284 (defface elpher-gemini-heading3
285 '((t :inherit bold :height 1.2))
286 "Face used for gemini heading level 3.")
288 (defface elpher-gemini-preformatted
289 '((t :inherit fixed-pitch))
290 "Face used for pre-formatted gemini text blocks.")
292 (defface elpher-gemini-quoted
293 '((t :inherit font-lock-doc-face))
294 "Face used for gemini quoted texts.")
301 ;; An elpher "address" object is either a url object or a symbol.
302 ;; Symbol addresses are "special", corresponding to pages generated
303 ;; dynamically for and by elpher. All others represent pages which
304 ;; rely on content retrieved over the network.
306 (defun elpher-address-from-url (url-string)
307 "Create a ADDRESS object corresponding to the given URL-STRING."
308 (let ((data (match-data))) ; Prevent parsing clobbering match data
310 (let ((url (url-generic-parse-url url-string)))
311 (unless (and (not (url-fullness url)) (url-type url))
312 (setf (url-fullness url) t)
313 (unless (url-type url)
314 (setf (url-type url) elpher-default-url-type))
315 (unless (url-host url)
316 (let ((p (split-string (url-filename url) "/" nil nil)))
317 (setf (url-host url) (car p))
318 (setf (url-filename url)
320 (concat "/" (mapconcat #'identity (cdr p) "/"))
322 (when (or (equal "gopher" (url-type url))
323 (equal "gophers" (url-type url)))
325 (when (or (equal (url-filename url) "")
326 (equal (url-filename url) "/"))
327 (setf (url-filename url) "/1")))
328 (when (equal "gemini" (url-type url))
330 (if (equal (url-filename url) "")
331 (setf (url-filename url) "/"))))
332 (elpher-remove-redundant-ports url))
333 (set-match-data data))))
335 (defun elpher-remove-redundant-ports (address)
336 "Remove redundant port specifiers from ADDRESS.
337 Here 'redundant' means that the specified port matches the default
338 for that protocol, eg 70 for gopher."
339 (if (and (not (elpher-address-special-p address))
340 (eq (url-portspec address) ; (url-port) is too slow!
341 (pcase (url-type address)
343 ((or "gopher" "gophers") 70)
346 (setf (url-portspec address) nil))
349 (defun elpher-make-gopher-address (type selector host port &optional tls)
350 "Create an ADDRESS object using gopher directory record attributes.
351 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
352 If the optional attribute TLS is non-nil, the address will be marked as
353 requiring gopher-over-TLS."
355 ((equal type ?i) nil)
356 ((and (equal type ?h)
357 (string-prefix-p "URL:" selector))
358 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
360 (elpher-address-from-url
363 ":" (number-to-string port))))
365 (elpher-address-from-url
366 (concat "gopher" (if tls "s" "")
368 ":" (number-to-string port)
372 (defun elpher-make-special-address (type)
373 "Create an ADDRESS object corresponding to the given special address symbol TYPE."
376 (defun elpher-address-to-url (address)
377 "Get string representation of ADDRESS, or nil if ADDRESS is special."
378 (if (elpher-address-special-p address)
380 (url-encode-url (url-recreate-url address))))
382 (defun elpher-address-type (address)
383 "Retrieve type of ADDRESS object.
384 This is used to determine how to retrieve and render the document the
385 address refers to, via the table `elpher-type-map'."
386 (if (symbolp address)
387 (list 'special address)
388 (let ((protocol (url-type address)))
389 (cond ((or (equal protocol "gopher")
390 (equal protocol "gophers"))
392 (if (member (url-filename address) '("" "/"))
394 (string-to-char (substring (url-filename address) 1)))))
395 ((equal protocol "gemini")
397 ((equal protocol "telnet")
399 ((equal protocol "finger")
403 (defun elpher-address-protocol (address)
404 "Retrieve the transport protocol for ADDRESS. This is nil for special addresses."
405 (if (symbolp address)
409 (defun elpher-address-filename (address)
410 "Retrieve the filename component of ADDRESS.
411 For gopher addresses this is a combination of the selector type and selector."
412 (if (symbolp address)
414 (url-unhex-string (url-filename address))))
416 (defun elpher-address-host (address)
417 "Retrieve host from ADDRESS object."
420 (defun elpher-address-user (address)
421 "Retrieve user from ADDRESS object."
424 (defun elpher-address-port (address)
425 "Retrieve port from ADDRESS object.
426 If no address is defined, returns 0. (This is for compatibility with the URL library.)"
427 (if (symbolp address)
431 (defun elpher-address-special-p (address)
432 "Return non-nil if ADDRESS object is special (e.g. start page page)."
435 (defun elpher-address-gopher-p (address)
436 "Return non-nill if ADDRESS object is a gopher address."
437 (and (not (elpher-address-special-p address))
438 (member (elpher-address-protocol address) '("gopher" "gophers"))))
440 (defun elpher-gopher-address-selector (address)
441 "Retrieve gopher selector from ADDRESS object."
442 (if (member (url-filename address) '("" "/"))
444 (url-unhex-string (substring (url-filename address) 2))))
449 (defvar elpher-content-cache (make-hash-table :test 'equal))
450 (defvar elpher-pos-cache (make-hash-table :test 'equal))
452 (defun elpher-get-cached-content (address)
453 "Retrieve the cached content for ADDRESS, or nil if none exists."
454 (gethash address elpher-content-cache))
456 (defun elpher-cache-content (address content)
457 "Set the content cache for ADDRESS to CONTENT."
458 (puthash address content elpher-content-cache))
460 (defun elpher-get-cached-pos (address)
461 "Retrieve the cached cursor position for ADDRESS, or nil if none exists."
462 (gethash address elpher-pos-cache))
464 (defun elpher-cache-pos (address pos)
465 "Set the cursor position cache for ADDRESS to POS."
466 (puthash address pos elpher-pos-cache))
471 (defun elpher-make-page (display-string address)
472 "Create a page with DISPLAY-STRING and ADDRESS."
473 (list display-string address))
475 (defun elpher-make-start-page ()
476 "Create the start page."
477 (elpher-make-page "Elpher Start Page"
478 (elpher-make-special-address 'start)))
480 (defun elpher-page-display-string (page)
481 "Retrieve the display string corresponding to PAGE."
484 (defun elpher-page-address (page)
485 "Retrieve the address corresponding to PAGE."
488 (defun elpher-page-set-address (page new-address)
489 "Set the address corresponding to PAGE to NEW-ADDRESS."
490 (setcar (cdr page) new-address))
492 (defvar elpher-current-page nil
493 "The current page for this Elpher buffer.")
495 (defvar elpher-history nil
496 "The local history stack for this Elpher buffer.
497 This variable is used by `elpher-back' and
498 `elpher-show-history'.")
500 (defvar elpher-visited-pages nil
501 "The global history for all Elpher buffers.
502 This variable is used by `elpher-show-visited-pages'.")
504 (defun elpher-visit-page (page &optional renderer no-history)
505 "Visit PAGE using its own renderer or RENDERER, if non-nil.
506 Additionally, push PAGE onto the history stack and the list of
507 previously-visited pages,unless NO-HISTORY is non-nil."
509 (elpher-process-cleanup)
511 (unless (equal (elpher-page-address elpher-current-page)
512 (elpher-page-address page))
513 (push elpher-current-page elpher-history)
514 (unless (or (elpher-address-special-p (elpher-page-address page))
515 (and elpher-visited-pages
516 (equal page (car elpher-visited-pages))))
517 (push page elpher-visited-pages))))
518 (setq-local elpher-current-page page)
519 (let* ((address (elpher-page-address page))
520 (type (elpher-address-type address))
521 (type-record (cdr (assoc type elpher-type-map))))
523 (funcall (car type-record)
527 (elpher-visit-previous-page)
529 (`(gopher ,type-char)
530 (error "Unsupported gopher selector type '%c' for '%s'"
531 type-char (elpher-address-to-url address)))
533 (error "Unsupported address type '%S' for '%s'"
534 other (elpher-address-to-url address)))))))
536 (defun elpher-visit-previous-page ()
537 "Visit the previous page in the history."
538 (let ((previous-page (pop elpher-history)))
540 (elpher-visit-page previous-page nil t)
541 (error "No previous page"))))
543 (defun elpher-reload-current-page ()
544 "Reload the current page, discarding any existing cached content."
545 (elpher-cache-content (elpher-page-address elpher-current-page) nil)
546 (elpher-visit-page elpher-current-page))
548 (defun elpher-save-pos ()
549 "Save the current position of point to the current page."
550 (when elpher-current-page
551 (elpher-cache-pos (elpher-page-address elpher-current-page) (point))))
553 (defun elpher-restore-pos ()
554 "Restore the position of point to that cached in the current page."
555 (let ((pos (elpher-get-cached-pos (elpher-page-address elpher-current-page))))
558 (goto-char (point-min)))))
561 ;;; Buffer preparation
564 (defvar elpher-buffer-name "*elpher*"
565 "The default name of the Elpher buffer.")
567 (defun elpher-update-header ()
568 "If `elpher-use-header' is true, display current page info in window header."
569 (if elpher-use-header
570 (let* ((display-string (elpher-page-display-string elpher-current-page))
571 (address (elpher-page-address elpher-current-page))
572 (tls-string (if (and (not (elpher-address-special-p address))
573 (member (elpher-address-protocol address)
574 '("gophers" "gemini")))
577 (header (concat display-string
578 (propertize tls-string 'face 'bold))))
579 (setq header-line-format header))))
581 (defmacro elpher-with-clean-buffer (&rest args)
582 "Evaluate ARGS with a clean *elpher* buffer as current."
583 `(with-current-buffer elpher-buffer-name
584 (unless (eq major-mode 'elpher-mode)
585 ;; avoid resetting buffer-local variables
587 (let ((inhibit-read-only t)
588 (ansi-color-context nil)) ;; clean ansi interpreter state
589 (setq-local network-security-level
590 (default-value 'network-security-level))
592 (elpher-update-header)
595 (defun elpher-buffer-message (string &optional line)
596 "Replace first line in elpher buffer with STRING.
597 If LINE is non-nil, replace that line instead."
598 (with-current-buffer elpher-buffer-name
599 (let ((inhibit-read-only t))
600 (goto-char (point-min))
603 (let ((data (match-data)))
606 (re-search-forward "^.*$")
607 (replace-match string))
608 (set-match-data data))))))
614 (defvar elpher-user-coding-system nil
615 "User-specified coding system to use for decoding text responses.")
617 (defun elpher-decode (string)
618 "Decode STRING using autodetected or user-specified coding system."
619 (decode-coding-string string
620 (if elpher-user-coding-system
621 elpher-user-coding-system
622 (detect-coding-string string t))))
624 (defun elpher-preprocess-text-response (string)
625 "Preprocess text selector response contained in STRING.
626 This involes decoding the character representation, and clearing
627 away CRs and any terminating period."
628 (elpher-decode (replace-regexp-in-string "\n\\.\n$" "\n"
629 (replace-regexp-in-string "\r" "" string))))
633 (defconst elpher-url-regex
634 "\\([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_~?/@|#-]\\)?\\)?"
635 "Regexp used to locate and buttonify URLs in text files loaded by elpher.")
637 (defun elpher-buttonify-urls (string)
638 "Turn substrings which look like urls in STRING into clickable buttons."
641 (goto-char (point-min))
642 (while (re-search-forward elpher-url-regex nil t)
643 (let ((page (elpher-make-page (substring-no-properties (match-string 0))
644 (elpher-address-from-url (match-string 0)))))
645 (make-text-button (match-beginning 0)
648 'action #'elpher-click-link
650 'help-echo #'elpher--page-button-help
654 ;;; ANSI colors or XTerm colors (application and filtering)
656 (or (require 'xterm-color nil t)
657 (require 'ansi-color))
659 (defalias 'elpher-color-filter-apply
660 (if (fboundp 'xterm-color-filter)
662 (let ((_xterm-color-render nil))
663 (xterm-color-filter s)))
664 #'ansi-color-filter-apply)
665 "A function to filter out ANSI escape sequences.")
667 (defalias 'elpher-color-apply
668 (if (fboundp 'xterm-color-filter)
671 "A function to apply ANSI escape sequences.")
673 ;;; Processing text for display
675 (defun elpher-process-text-for-display (string)
676 "Perform any desired processing of STRING prior to display as text.
677 Currently includes buttonifying URLs and processing ANSI escape codes."
678 (elpher-buttonify-urls (if elpher-filter-ansi-from-text
679 (elpher-color-filter-apply string)
680 (elpher-color-apply string))))
683 ;;; Network error reporting
686 (defun elpher-network-error (address error)
687 "Display ERROR message following unsuccessful negotiation with ADDRESS.
688 ERROR can be either an error object or a string."
689 (elpher-with-clean-buffer
690 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
691 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
692 (if (stringp error) error (error-message-string error)) "\n"
693 (propertize "\n----------------\n\n" 'face 'error)
694 "Press 'u' to return to the previous page.")))
697 ;;; General network communication
700 (defvar elpher-network-timer nil
701 "Timer used for network connections.")
703 (defvar elpher-use-tls nil
704 "If non-nil, use TLS to communicate with gopher servers.")
706 (defvar elpher-client-certificate nil
707 "If non-nil, contains client certificate details to use for TLS connections.")
709 (defun elpher-process-cleanup ()
710 "Immediately shut down any extant elpher process and timers."
711 (let ((p (get-process "elpher-process")))
712 (if p (delete-process p)))
713 (if (timerp elpher-network-timer)
714 (cancel-timer elpher-network-timer)))
716 (defun elpher-make-network-timer (thunk)
717 "Creates a timer to run the THUNK after `elpher-connection-timeout' seconds.
718 This is just a wraper around `run-at-time' which additionally sets the
719 buffer-local variable `elpher-network-timer' to allow
720 `elpher-process-cleanup' to also clear the timer."
721 (let ((timer (run-at-time elpher-connection-timeout nil thunk)))
722 (setq-local elpher-network-timer timer)
725 (defun elpher-get-host-response (address default-port query-string response-processor
726 &optional use-tls force-ipv4)
727 "Generic function for retrieving data from ADDRESS.
729 When ADDRESS lacks a specific port, DEFAULT-PORT is used instead.
730 QUERY-STRING is a string sent to the host specified by ADDRESS to
731 illicet a response. This response is passed as an argument to the
732 function RESPONSE-PROCESSOR.
734 If non-nil, USE-TLS specifies that the connection is to be made over
735 TLS. If set to gemini, the certificate verification will be disabled
736 unless `elpher-gemini-TLS-cert-checks' is non-nil.
738 If non-nil, FORCE-IPV4 causes the network connection to be made over
739 ipv4 only. (The default behaviour when this is not set depends on
740 the host operating system and the local network capabilities.)"
741 (if (and use-tls (not (gnutls-available-p)))
742 (error "Use of TLS requires Emacs to be compiled with GNU TLS support")
743 (unless (< (elpher-address-port address) 65536)
744 (error "Cannot establish network connection: port number > 65536"))
745 (when (and (eq use-tls 'gemini) (not elpher-gemini-TLS-cert-checks))
746 (setq-local network-security-level 'low)
747 (setq-local gnutls-verify-error nil))
749 (let* ((kill-buffer-query-functions nil)
750 (port (elpher-address-port address))
751 (host (elpher-address-host address))
752 (service (if (> port 0) port default-port))
753 (response-string-parts nil)
756 (socks (or elpher-socks-always (string-suffix-p ".onion" host)))
757 (gnutls-params (list :type 'gnutls-x509pki
760 (elpher-get-current-keylist address)))
761 (timer (elpher-make-network-timer
763 (elpher-process-cleanup)
765 ; Try again with IPv4
766 ((not (or force-ipv4 socks))
767 (message "Connection timed out. Retrying with IPv4.")
768 (elpher-get-host-response address default-port
773 (not (eq use-tls 'gemini))
774 (or elpher-auto-disengage-TLS
776 "TLS connetion failed. Disable TLS mode and retry? ")))
777 (setq elpher-use-tls nil)
778 (elpher-get-host-response address default-port
783 (elpher-network-error address "Connection time-out."))))))
784 (proc (if socks (socks-open-network-stream "elpher-process" nil host service)
785 (make-network-process :name "elpher-process"
787 :family (and force-ipv4 'ipv4)
793 (cons 'gnutls-x509pki
794 (apply #'gnutls-boot-parameters
796 (setq elpher-network-timer timer)
797 (set-process-coding-system proc 'binary 'binary)
798 (set-process-query-on-exit-flag proc nil)
799 (elpher-buffer-message (concat "Connecting to " host "..."
800 " (press 'u' to abort)"))
801 (set-process-filter proc
802 (lambda (_proc string)
806 (setq bytes-received (+ bytes-received (length string)))
807 (let ((new-hkbytes-received (/ bytes-received 102400)))
808 (when (> new-hkbytes-received hkbytes-received)
809 (setq hkbytes-received new-hkbytes-received)
810 (elpher-buffer-message
812 (number-to-string (/ hkbytes-received 10.0))
815 (setq response-string-parts
816 (cons string response-string-parts))))
817 (set-process-sentinel proc
820 (cancel-timer timer))
821 (condition-case the-error
823 ((string-prefix-p "open" event) ; request URL
824 (elpher-buffer-message
825 (concat "Connected to " host ". Receiving data..."
826 " (press 'u' to abort)"))
827 (let ((inhibit-eol-conversion t))
828 (process-send-string proc query-string)))
829 ((string-prefix-p "deleted" event)) ; do nothing
830 ((and (not response-string-parts)
831 (not (or elpher-ipv4-always force-ipv4 socks)))
832 ; Try again with IPv4
833 (message "Connection failed. Retrying with IPv4.")
834 (elpher-get-host-response address default-port
838 (response-string-parts
839 (elpher-with-clean-buffer
840 (insert "Data received. Rendering..."))
841 (funcall response-processor
842 (apply #'concat (reverse response-string-parts)))
843 (elpher-restore-pos))
845 (error "No response from server")))
847 (elpher-network-error address the-error)))))
849 (if use-tls (apply #'gnutls-negotiate :process proc gnutls-params))
850 (funcall (process-sentinel proc) proc "open\n")))
852 (elpher-process-cleanup)
853 (error "Error initiating connection to server")))))
856 ;;; Client-side TLS Certificate Management
859 (defun elpher-generate-certificate (common-name key-file cert-file &optional temporary)
860 "Generate a key and a self-signed client TLS certificate using openssl.
862 The Common Name field of the certificate is set to COMMON-NAME. The
863 arguments KEY-FILE and CERT-FILE should contain the absolute paths of
864 the key and certificate files to write.
866 If TEMPORARY is non-nil, the certificate will be given an exporation
867 period of one day, and the key and certificate files will be deleted
868 when the certificate is no longer needed for the current session.
870 Otherwise, the certificate will be given a 100 year expiration period
871 and the files will not be deleted.
873 The function returns a list containing the current host name, the
874 temporary flag, and the key and cert file names in the form required
875 by `gnutls-boot-parameters`."
876 (let ((exp-key-file (expand-file-name key-file))
877 (exp-cert-file (expand-file-name cert-file)))
880 (call-process elpher-openssl-command nil nil nil
881 "req" "-x509" "-newkey" "rsa:2048"
882 "-days" (if temporary "1" "36500")
884 "-subj" (concat "/CN=" common-name)
885 "-keyout" exp-key-file
886 "-out" exp-cert-file)
887 (list (elpher-address-host (elpher-page-address elpher-current-page))
888 temporary exp-key-file exp-cert-file))
890 (message "Check that openssl is installed, or customize `elpher-openssl-command`.")
891 (error "Program 'openssl', required for certificate generation, not found")))))
893 (defun elpher-generate-throwaway-certificate ()
894 "Generate and return details of a throwaway certificate.
895 The key and certificate files will be deleted when they are no
896 longer needed for this session."
897 (let* ((file-base (make-temp-name "elpher"))
898 (key-file (concat temporary-file-directory file-base ".key"))
899 (cert-file (concat temporary-file-directory file-base ".crt")))
900 (elpher-generate-certificate file-base key-file cert-file t)))
902 (defun elpher-generate-persistent-certificate (file-base common-name)
903 "Generate and return details of a persistent certificate.
904 The argument FILE-BASE is used as the base for the key and certificate
905 files, while COMMON-NAME specifies the common name field of the
908 The key and certificate files are written to in `elpher-certificate-directory'."
909 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
910 (cert-file (concat elpher-certificate-directory file-base ".crt")))
911 (elpher-generate-certificate common-name key-file cert-file)))
913 (defun elpher-get-existing-certificate (file-base)
914 "Return a certificate object corresponding to an existing certificate.
915 It is assumed that the key files FILE-BASE.key and FILE-BASE.crt exist in
916 the directory `elpher-certificate-directory'."
917 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
918 (cert-file (concat elpher-certificate-directory file-base ".crt")))
919 (list (elpher-address-host (elpher-page-address elpher-current-page))
921 (expand-file-name key-file)
922 (expand-file-name cert-file))))
924 (defun elpher-install-and-use-existing-certificate (key-file-src cert-file-src file-base)
925 "Install a key+certificate file pair in `elpher-certificate-directory'.
926 The strings KEY-FILE-SRC and CERT-FILE-SRC are the existing key and
927 certificate files to install. The argument FILE-BASE is used as the
928 base for the installed key and certificate files."
929 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
930 (cert-file (concat elpher-certificate-directory file-base ".crt")))
931 (if (or (file-exists-p key-file)
932 (file-exists-p cert-file))
933 (error "A certificate with base name %s is already installed" file-base))
934 (copy-file key-file-src key-file)
935 (copy-file cert-file-src cert-file)
936 (list (elpher-address-host (elpher-page-address elpher-current-page))
938 (expand-file-name key-file)
939 (expand-file-name cert-file))))
941 (defun elpher-list-existing-certificates ()
942 "Return a list of the persistent certificates in `elpher-certificate-directory'."
943 (unless (file-directory-p elpher-certificate-directory)
944 (make-directory elpher-certificate-directory))
947 (file-name-sans-extension file))
948 (directory-files elpher-certificate-directory nil "\\.key$")))
950 (defun elpher-forget-current-certificate ()
951 "Causes any current certificate to be forgotten.)
952 In the case of throwaway certificates, the key and certificate files
955 (when elpher-client-certificate
956 (unless (and (called-interactively-p 'any)
957 (not (y-or-n-p (concat "Really forget client certificate? "
958 "(Throwaway certificates will be deleted.)"))))
959 (when (cadr elpher-client-certificate)
960 (delete-file (elt elpher-client-certificate 2))
961 (delete-file (elt elpher-client-certificate 3)))
962 (setq elpher-client-certificate nil)
963 (if (called-interactively-p 'any)
964 (message "Client certificate forgotten.")))))
966 (defun elpher-get-current-keylist (address)
967 "Retrieve the `gnutls-boot-parameters'-compatable keylist.
969 This is obtained from the client certificate described by
970 `elpher-current-certificate', if one is available and the host for
971 that certificate matches the host in ADDRESS.
973 If `elpher-current-certificate' is non-nil, and its host name doesn't
974 match that of ADDRESS, the certificate is forgotten."
975 (if elpher-client-certificate
976 (if (string= (car elpher-client-certificate)
977 (elpher-address-host address))
978 (list (cddr elpher-client-certificate))
979 (elpher-forget-current-certificate)
980 (message "Disabling client certificate for new host")
985 ;;; Gopher selector retrieval
988 (defun elpher-get-gopher-response (address renderer)
989 "Get response string from gopher server at ADDRESS and render using RENDERER."
990 (elpher-get-host-response address 70
991 (concat (elpher-gopher-address-selector address) "\r\n")
993 (or (string= (elpher-address-protocol address) "gophers")
996 (defun elpher-get-gopher-page (renderer)
997 "Getter function for gopher pages.
998 The RENDERER procedure is used to display the contents of the page
999 once they are retrieved from the gopher server."
1000 (let* ((address (elpher-page-address elpher-current-page))
1001 (content (elpher-get-cached-content address)))
1002 (if (and content (funcall renderer nil))
1003 (elpher-with-clean-buffer
1005 (elpher-restore-pos))
1006 (elpher-with-clean-buffer
1007 (insert "LOADING... (use 'u' to cancel)\n"))
1008 (condition-case the-error
1009 (elpher-get-gopher-response address renderer)
1011 (elpher-network-error address the-error))))))
1015 (defun elpher-insert-index (string)
1016 "Insert the index corresponding to STRING into the current buffer."
1017 ;; Should be able to split directly on CRLF, but some non-conformant
1018 ;; LF-only servers sadly exist, hence the following.
1019 (let ((str-processed (elpher-preprocess-text-response string)))
1020 (dolist (line (split-string str-processed "\n"))
1022 (unless (= (length line) 0)
1023 (let* ((type (elt line 0))
1024 (fields (split-string (substring line 1) "\t"))
1025 (display-string (elt fields 0))
1026 (selector (elt fields 1))
1027 (host (elt fields 2))
1028 (port (if (elt fields 3)
1029 (string-to-number (elt fields 3))
1031 (address (elpher-make-gopher-address type selector host port)))
1032 (elpher-insert-index-record display-string address)))))))
1034 (defun elpher-insert-margin (&optional type-name)
1035 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
1038 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
1040 (propertize "[" 'face 'elpher-margin-brackets)
1041 (propertize type-name 'face 'elpher-margin-key)
1042 (propertize "]" 'face 'elpher-margin-brackets))))
1044 (insert (make-string elpher-margin-width ?\s))))
1046 (defun elpher--page-button-help (_window buffer pos)
1047 "Function called by Emacs to generate mouse-over text.
1048 The arguments specify the BUFFER and the POS within the buffer of the item
1049 for which help is required. The function returns the help to be
1050 displayed. The _WINDOW argument is currently unused."
1051 (with-current-buffer buffer
1052 (let ((button (button-at pos)))
1054 (let* ((page (button-get button 'elpher-page))
1055 (address (elpher-page-address page)))
1056 (format "mouse-1, RET: open '%s'" (if (elpher-address-special-p address)
1058 (elpher-address-to-url address))))))))
1060 (defun elpher-insert-index-record (display-string &optional address)
1061 "Function to insert an index record into the current buffer.
1062 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
1063 If ADDRESS is not supplied or nil the record is rendered as an
1064 'information' line."
1065 (let* ((type (if address (elpher-address-type address) nil))
1066 (type-map-entry (cdr (assoc type elpher-type-map))))
1068 (let* ((margin-code (elt type-map-entry 2))
1069 (face (elt type-map-entry 3))
1070 (filtered-display-string (elpher-color-filter-apply display-string))
1071 (page (elpher-make-page filtered-display-string address)))
1072 (elpher-insert-margin margin-code)
1073 (insert-text-button filtered-display-string
1076 'action #'elpher-click-link
1078 'help-echo #'elpher--page-button-help))
1080 ('nil ;; Information
1081 (elpher-insert-margin)
1082 (let ((propertized-display-string
1083 (propertize display-string 'face 'elpher-info)))
1084 (insert (elpher-process-text-for-display propertized-display-string))))
1085 (`(gopher ,selector-type) ;; Unknown
1086 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
1087 (insert (propertize display-string
1088 'face 'elpher-unknown)))))
1091 (defun elpher-click-link (button)
1092 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
1093 (let ((page (button-get button 'elpher-page)))
1094 (elpher-visit-page page)))
1096 (defun elpher-render-index (data &optional _mime-type-string)
1097 "Render DATA as an index. MIME-TYPE-STRING is unused."
1098 (elpher-with-clean-buffer
1101 (elpher-insert-index data)
1102 (elpher-cache-content (elpher-page-address elpher-current-page)
1107 (defun elpher-render-text (data &optional _mime-type-string)
1108 "Render DATA as text. MIME-TYPE-STRING is unused."
1109 (elpher-with-clean-buffer
1112 (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
1113 (elpher-cache-content
1114 (elpher-page-address elpher-current-page)
1119 (defun elpher-render-image (data &optional _mime-type-string)
1120 "Display DATA as image. MIME-TYPE-STRING is unused."
1123 (if (display-images-p)
1125 (let ((image (create-image
1128 (elpher-with-clean-buffer
1129 (insert-image image)
1130 (elpher-restore-pos))))
1131 (elpher-render-download data))))
1133 ;; Search retrieval and rendering
1135 (defun elpher-get-gopher-query-page (renderer)
1136 "Getter for gopher addresses requiring input.
1137 The response is rendered using the rendering function RENDERER."
1138 (let* ((address (elpher-page-address elpher-current-page))
1139 (content (elpher-get-cached-content address))
1141 (if (and content (funcall renderer nil))
1142 (elpher-with-clean-buffer
1144 (elpher-restore-pos)
1145 (message "Displaying cached search results. Reload to perform a new search."))
1147 (let* ((query-string (read-string "Query: "))
1148 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
1149 (search-address (elpher-make-gopher-address ?1
1151 (elpher-address-host address)
1152 (elpher-address-port address)
1153 (equal (elpher-address-type address) "gophers"))))
1156 (elpher-with-clean-buffer
1157 (insert "LOADING RESULTS... (use 'u' to cancel)"))
1158 (elpher-get-gopher-response search-address renderer))
1160 (elpher-visit-previous-page))))))
1162 ;; Raw server response rendering
1164 (defun elpher-render-raw (data &optional mime-type-string)
1165 "Display raw DATA in buffer. MIME-TYPE-STRING is also displayed if provided."
1168 (elpher-with-clean-buffer
1169 (when mime-type-string
1170 (insert "MIME type specified by server: '" mime-type-string "'\n"))
1172 (goto-char (point-min)))
1173 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
1175 ;; File save "rendering"
1177 (defun elpher-render-download (data &optional _mime-type-string)
1178 "Save DATA to file. MIME-TYPE-STRING is unused."
1181 (let* ((address (elpher-page-address elpher-current-page))
1182 (selector (if (elpher-address-gopher-p address)
1183 (elpher-gopher-address-selector address)
1184 (elpher-address-filename address))))
1185 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1186 (let* ((filename-proposal (file-name-nondirectory selector))
1187 (filename (read-file-name "Download complete. Save file as: "
1189 (if (> (length filename-proposal) 0)
1192 (let ((coding-system-for-write 'binary))
1193 (with-temp-file filename
1195 (message (format "Saved to file %s." filename))))))
1199 (defun elpher-render-html (data &optional _mime-type-string)
1200 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
1201 (elpher-with-clean-buffer
1204 (let ((dom (with-temp-buffer
1206 (libxml-parse-html-region (point-min) (point-max)))))
1207 (shr-insert-document dom)))))
1209 ;; Gemini page retrieval
1211 (defvar elpher-gemini-redirect-chain)
1213 (defun elpher-get-gemini-response (address renderer)
1214 "Get response string from gemini server at ADDRESS and render using RENDERER."
1215 (elpher-get-host-response address 1965
1216 (concat (elpher-address-to-url address) "\r\n")
1217 (lambda (response-string)
1218 (elpher-process-gemini-response response-string renderer))
1221 (defun elpher-parse-gemini-response (response)
1222 "Parse the RESPONSE string and return a list of components.
1223 The list is of the form (code meta body). A response of nil implies
1224 that the response was malformed."
1225 (let ((header-end-idx (string-match "\r\n" response)))
1227 (let ((header (string-trim (substring response 0 header-end-idx)))
1228 (body (substring response (+ header-end-idx 2))))
1229 (if (>= (length header) 2)
1230 (let ((code (substring header 0 2))
1231 (meta (string-trim (substring header 2))))
1232 (list code meta body))
1233 (error "Malformed response: No response status found in header %s" header)))
1234 (error "Malformed response: No CRLF-delimited header found in response %s" response))))
1236 (defun elpher-process-gemini-response (response-string renderer)
1237 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
1238 (let ((response-components (elpher-parse-gemini-response response-string)))
1239 (let ((response-code (elt response-components 0))
1240 (response-meta (elt response-components 1))
1241 (response-body (elt response-components 2)))
1242 (pcase (elt response-code 0)
1243 (?1 ; Input required
1244 (elpher-with-clean-buffer
1245 (insert "Gemini server is requesting input."))
1246 (let* ((query-string
1247 (if (eq (elt response-code 1) ?1)
1248 (read-passwd (concat response-meta ": "))
1249 (read-string (concat response-meta ": "))))
1250 (query-address (seq-copy (elpher-page-address elpher-current-page)))
1251 (old-fname (url-filename query-address)))
1252 (setf (url-filename query-address)
1253 (concat old-fname "?" (url-build-query-string `((,query-string)))))
1254 (elpher-get-gemini-response query-address renderer)))
1255 (?2 ; Normal response
1256 (funcall renderer response-body response-meta))
1258 (message "Following redirect to %s" response-meta)
1259 (if (>= (length elpher-gemini-redirect-chain) 5)
1260 (error "More than 5 consecutive redirects followed"))
1261 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
1262 (if (member redirect-address elpher-gemini-redirect-chain)
1263 (error "Redirect loop detected"))
1264 (if (not (string= (elpher-address-protocol redirect-address)
1266 (error "Server tried to automatically redirect to non-gemini URL: %s"
1268 (elpher-page-set-address elpher-current-page redirect-address)
1269 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
1270 (elpher-get-gemini-response redirect-address renderer)))
1271 (?4 ; Temporary failure
1272 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
1273 response-code response-meta))
1274 (?5 ; Permanent failure
1275 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
1276 response-code response-meta))
1277 (?6 ; Client certificate required
1278 (elpher-with-clean-buffer
1279 (if elpher-client-certificate
1280 (insert "Gemini server does not recognise the provided TLS certificate:\n\n")
1281 (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
1283 (elpher-gemini-insert-text response-meta))
1284 (let ((chosen-certificate (elpher-choose-client-certificate)))
1285 (unless chosen-certificate
1286 (error "Gemini server requires a client certificate and none was provided"))
1287 (setq elpher-client-certificate chosen-certificate))
1288 (elpher-with-clean-buffer)
1289 (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer))
1291 (error "Gemini server response unknown: %s %s"
1292 response-code response-meta))))))
1294 (defun elpher--read-answer-polyfill (question answers)
1295 "Polyfill for `read-answer' in Emacs 26.1.
1296 QUESTION is a string containing a question, and ANSWERS
1297 is a list of possible answers."
1298 (completing-read question (mapcar 'identity answers)))
1300 (if (fboundp 'read-answer)
1301 (defalias 'elpher-read-answer 'read-answer)
1302 (defalias 'elpher-read-answer 'elpher--read-answer-polyfill))
1304 (defun elpher-choose-client-certificate ()
1305 "Prompt for a client certificate to use to establish a TLS connection."
1306 (let* ((read-answer-short t))
1307 (pcase (read-answer "What do you want to do? "
1309 "generate and use throw-away certificate")
1311 "generate new or use existing persistent certificate")
1313 "stop immediately")))
1315 (setq elpher-client-certificate (elpher-generate-throwaway-certificate)))
1317 (let* ((existing-certificates (elpher-list-existing-certificates))
1318 (file-base (completing-read
1319 "Nickname for new or existing certificate (autocompletes, empty response aborts): "
1320 existing-certificates)))
1321 (if (string-empty-p (string-trim file-base))
1323 (if (member file-base existing-certificates)
1324 (setq elpher-client-certificate
1325 (elpher-get-existing-certificate file-base))
1326 (pcase (read-answer "Generate new certificate or install externally-generated one? "
1328 "generate new certificate")
1330 "install existing certificate")
1332 "stop immediately")))
1334 (let ((common-name (read-string "Common Name field for new certificate: "
1336 (message "New key and self-signed certificate written to %s"
1337 elpher-certificate-directory)
1338 (elpher-generate-persistent-certificate file-base common-name)))
1340 (let* ((cert-file (read-file-name "Certificate file: " nil nil t))
1341 (key-file (read-file-name "Key file: " nil nil t)))
1342 (message "Key and certificate installed in %s for future use"
1343 elpher-certificate-directory)
1344 (elpher-install-and-use-existing-certificate key-file
1350 (defun elpher-get-gemini-page (renderer)
1351 "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
1352 (let* ((address (elpher-page-address elpher-current-page))
1353 (content (elpher-get-cached-content address)))
1354 (condition-case the-error
1355 (if (and content (funcall renderer nil))
1356 (elpher-with-clean-buffer
1358 (elpher-restore-pos))
1359 (elpher-with-clean-buffer
1360 (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
1361 (setq elpher-gemini-redirect-chain nil)
1362 (elpher-get-gemini-response address renderer))
1364 (elpher-network-error address the-error)))))
1366 (defun elpher-render-gemini (body &optional mime-type-string)
1367 "Render gemini response BODY with rendering MIME-TYPE-STRING."
1370 (let* ((mime-type-string* (if (or (not mime-type-string)
1371 (string-empty-p mime-type-string))
1372 "text/gemini; charset=utf-8"
1374 (mime-type-split (split-string mime-type-string* ";" t))
1375 (mime-type (string-trim (car mime-type-split)))
1376 (parameters (mapcar (lambda (s)
1377 (let ((key-val (split-string s "=")))
1378 (list (downcase (string-trim (car key-val)))
1379 (downcase (string-trim (cadr key-val))))))
1380 (cdr mime-type-split))))
1381 (when (string-prefix-p "text/" mime-type)
1382 (setq body (decode-coding-string
1384 (if (assoc "charset" parameters)
1385 (intern (cadr (assoc "charset" parameters)))
1387 (setq body (replace-regexp-in-string "\r" "" body)))
1389 ((or "text/gemini" "")
1390 (elpher-render-gemini-map body parameters))
1392 (elpher-render-html body))
1393 ((pred (string-prefix-p "text/"))
1394 (elpher-render-gemini-plain-text body parameters))
1395 ((pred (string-prefix-p "image/"))
1396 (elpher-render-image body))
1398 (elpher-render-download body))))))
1400 (defun elpher-gemini-get-link-url (link-line)
1401 "Extract the url portion of LINK-LINE, a gemini map file link line.
1402 Returns nil in the event that the contents of the line following the
1403 => prefix are empty."
1404 (let ((l (split-string (substring link-line 2))))
1406 (string-trim (elt l 0))
1409 (defun elpher-gemini-get-link-display-string (link-line)
1410 "Extract the display string portion of LINK-LINE, a gemini map file link line.
1411 Returns the url portion in the event that the display-string portion is empty."
1412 (let* ((rest (string-trim (elt (split-string link-line "=>") 1)))
1413 (idx (string-match "[ \t]" rest)))
1414 (string-trim (if idx
1415 (substring rest (+ idx 1))
1418 (defun elpher-collapse-dot-sequences (filename)
1419 "Collapse dot sequences in FILENAME.
1420 For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
1421 (let* ((path (split-string filename "/"))
1422 (path-reversed-normalized
1423 (seq-reduce (lambda (a b)
1424 (cond ((and a (equal b "..") (cdr a)))
1425 ((and (not a) (equal b "..")) a) ;leading .. are dropped
1429 (string-join (reverse path-reversed-normalized) "/")))
1431 (defun elpher-address-from-gemini-url (url)
1432 "Extract address from URL with defaults as per gemini map files.
1433 While there's obviously some redundancy here between this function and
1434 `elpher-address-from-url', gemini map file URLs require enough special
1435 treatment that a separate function is warranted."
1436 (let ((address (url-generic-parse-url url))
1437 (current-address (elpher-page-address elpher-current-page)))
1438 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
1439 (setf (url-fullness address) t)
1440 (if (url-host address) ;if there is an explicit host, filenames are absolute
1441 (if (string-empty-p (url-filename address))
1442 (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
1443 (setf (url-host address) (url-host current-address))
1444 (setf (url-port address) (url-port current-address))
1445 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
1446 (setf (url-filename address)
1447 (concat (file-name-directory (url-filename current-address))
1448 (url-filename address)))))
1449 (unless (url-type address)
1450 (setf (url-type address) "gemini"))
1451 (when (equal (url-type address) "gemini")
1452 (setf (url-filename address)
1453 (elpher-collapse-dot-sequences (url-filename address)))))
1454 (elpher-remove-redundant-ports address)))
1456 (defun elpher-gemini-insert-link (link-line)
1457 "Insert link described by LINK-LINE into a text/gemini document."
1458 (let* ((url (elpher-gemini-get-link-url link-line))
1459 (display-string (elpher-gemini-get-link-display-string link-line))
1460 (address (elpher-address-from-gemini-url url))
1461 (type (if address (elpher-address-type address) nil))
1462 (type-map-entry (cdr (assoc type elpher-type-map))))
1463 (when display-string
1464 (insert elpher-gemini-link-string)
1466 (let* ((face (elt type-map-entry 3))
1467 (filtered-display-string (elpher-color-filter-apply display-string))
1468 (page (elpher-make-page filtered-display-string address)))
1469 (insert-text-button filtered-display-string
1472 'action #'elpher-click-link
1474 'help-echo #'elpher--page-button-help))
1475 (insert (propertize display-string 'face 'elpher-unknown)))
1478 (defvar elpher--gemini-page-headings nil
1479 "List of headings on the page.")
1481 (defun elpher-gemini-insert-header (header-line)
1482 "Insert header described by HEADER-LINE into a text/gemini document.
1483 The gemini map file line describing the header is given
1485 (when (string-match "^\\(#+\\)[ \t]*" header-line)
1486 (let* ((level (length (match-string 1 header-line)))
1487 (header (substring header-line (match-end 0)))
1489 (1 'elpher-gemini-heading1)
1490 (2 'elpher-gemini-heading2)
1491 (3 'elpher-gemini-heading3)
1493 (fill-column (if (display-graphic-p)
1495 (font-get (font-spec :name (face-font 'default)) :size))
1496 (font-get (font-spec :name (face-font face)) :size)) fill-column)))
1497 (setq elpher--gemini-page-headings (cons (cons header (point))
1498 elpher--gemini-page-headings))
1499 (unless (display-graphic-p)
1500 (insert (make-string level ?#) " "))
1501 (insert (propertize header 'face face))
1504 (defun elpher-gemini-insert-text (text-line)
1505 "Insert a plain non-preformatted TEXT-LINE into a text/gemini document.
1506 This function uses Emacs' auto-fill to wrap text sensibly to a maximum
1507 width defined by `elpher-gemini-max-fill-width'."
1508 (string-match "\\(^[ \t]*\\)\\(\\*[ \t]+\\|>[ \t]*\\)?" text-line)
1509 (let* ((line-prefix (match-string 2 text-line))
1510 (processed-text-line
1512 (cond ((string-prefix-p "*" line-prefix)
1514 (replace-regexp-in-string "\\*"
1515 elpher-gemini-bullet-string
1516 (match-string 0 text-line))
1517 (substring text-line (match-end 0))))
1518 ((string-prefix-p ">" line-prefix)
1519 (propertize text-line 'face 'elpher-gemini-quoted))
1522 (adaptive-fill-mode t)
1523 ;; fill-prefix is important for adaptive-fill-mode: without
1524 ;; it, multi-line list items are not indented correct
1525 (fill-prefix (if (match-string 2 text-line)
1526 (replace-regexp-in-string "[>\*]" " " (match-string 0 text-line))
1528 (insert (elpher-process-text-for-display processed-text-line))
1531 (defun elpher-render-gemini-map (data _parameters)
1532 "Render DATA as a gemini map file, PARAMETERS is currently unused."
1533 (elpher-with-clean-buffer
1534 (setq elpher--gemini-page-headings nil)
1535 (let ((preformatted nil))
1537 (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))
1538 (dolist (line (split-string data "\n"))
1540 ((string-prefix-p "```" line) (setq preformatted (not preformatted)))
1541 (preformatted (insert (elpher-process-text-for-display
1542 (propertize line 'face 'elpher-gemini-preformatted))
1544 ((string-prefix-p "=>" line)
1545 (elpher-gemini-insert-link line))
1546 ((string-prefix-p "#" line) (elpher-gemini-insert-header line))
1547 (t (elpher-gemini-insert-text line)))))
1548 (setq elpher--gemini-page-headings (nreverse elpher--gemini-page-headings))
1549 (elpher-cache-content
1550 (elpher-page-address elpher-current-page)
1553 (defun elpher-render-gemini-plain-text (data _parameters)
1554 "Render DATA as plain text file. PARAMETERS is currently unused."
1555 (elpher-with-clean-buffer
1556 (insert (elpher-process-text-for-display data))
1557 (elpher-cache-content
1558 (elpher-page-address elpher-current-page)
1562 ;; Finger page connection
1564 (defun elpher-get-finger-page (renderer)
1565 "Opens a finger connection to the current page address.
1566 The result is rendered using RENDERER."
1567 (let* ((address (elpher-page-address elpher-current-page))
1568 (content (elpher-get-cached-content address)))
1569 (if (and content (funcall renderer nil))
1570 (elpher-with-clean-buffer
1572 (elpher-restore-pos))
1573 (elpher-with-clean-buffer
1574 (insert "LOADING... (use 'u' to cancel)\n"))
1575 (condition-case the-error
1576 (let* ((kill-buffer-query-functions nil)
1577 (user (let ((filename (elpher-address-filename address)))
1578 (if (> (length filename) 1)
1579 (substring filename 1)
1580 (elpher-address-user address)))))
1581 (elpher-get-host-response address 79
1582 (concat user "\r\n")
1585 (elpher-network-error address the-error))))))
1588 ;; Telnet page connection
1590 (defun elpher-get-telnet-page (renderer)
1591 "Opens a telnet connection to the current page address (RENDERER must be nil)."
1593 (elpher-visit-previous-page)
1594 (error "Command not supported for telnet URLs"))
1595 (let* ((address (elpher-page-address elpher-current-page))
1596 (host (elpher-address-host address))
1597 (port (elpher-address-port address)))
1598 (elpher-visit-previous-page)
1604 ;; Other URL page opening
1606 (defun elpher-get-other-url-page (renderer)
1607 "Getter which attempts to open the URL specified by the current page (RENDERER must be nil)."
1609 (elpher-visit-previous-page)
1610 (error "Command not supported for general URLs"))
1611 (let* ((address (elpher-page-address elpher-current-page))
1612 (url (elpher-address-to-url address)))
1614 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1615 (message "Opening URL...")
1616 (if elpher-open-urls-with-eww
1618 (browse-url url)))))
1621 ;; Start page retrieval
1623 (defun elpher-get-start-page (renderer)
1624 "Getter which displays the start page (RENDERER must be nil)."
1626 (elpher-visit-previous-page)
1627 (error "Command not supported for start page"))
1628 (elpher-with-clean-buffer
1629 (insert " --------------------------------------------\n"
1630 " Elpher Gopher and Gemini Client \n"
1631 " version " elpher-version "\n"
1632 " --------------------------------------------\n"
1634 "Default bindings:\n"
1636 " - TAB/Shift-TAB: next/prev item on current page\n"
1637 " - RET/mouse-1: open item under cursor\n"
1638 " - m: select an item on current page by name (autocompletes)\n"
1639 " - u/mouse-3/U: return to previous page or to the start page\n"
1640 " - g: go to a particular address (gopher, gemini, finger)\n"
1641 " - o/O: open a different address selector or the root menu of the current server\n"
1642 " - d/D: download item under cursor or current page\n"
1643 " - i/I: info on item under cursor or current page\n"
1644 " - c/C: copy URL representation of item under cursor or current page\n"
1645 " - a/A: bookmark the item under cursor or current page\n"
1646 " - B: list all bookmarks\n"
1647 " - s/S: show current history stack or all previously visted pages\n"
1648 " - r: redraw current page (using cached contents if available)\n"
1649 " - R: reload current page (regenerates cache)\n"
1650 " - !: set character coding system for gopher (default is to autodetect)\n"
1651 " - T: toggle TLS gopher mode\n"
1652 " - F: forget/discard current TLS client certificate\n"
1653 " - .: display the raw server response for the current page\n"
1655 "Start your exploration of gopher space and gemini:\n")
1656 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1657 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1658 (elpher-insert-index-record "Project Gemini home page"
1659 (elpher-address-from-url "gemini://gemini.circumlunar.space/"))
1661 "Alternatively, select a search engine and enter some search terms:\n")
1662 (elpher-insert-index-record "Gopher Search Engine (Veronica-2)"
1663 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1664 (elpher-insert-index-record "Gemini Search Engine (geminispace.info)"
1665 (elpher-address-from-url "gemini://geminispace.info/search"))
1667 "Your bookmarks are stored in your ")
1668 (let ((help-string "RET,mouse-1: Open Emacs bookmark list"))
1669 (insert-text-button "Emacs bookmark list"
1673 (call-interactively #'elpher-open-bookmarks))
1675 'help-echo help-string))
1678 "(Bookmarks from legacy elpher-bookmarks files will be automatically imported.)\n"
1681 "The gopher home of the Elpher project is here:\n")
1682 (elpher-insert-index-record "The Elpher Project Page"
1683 (elpher-make-gopher-address ?1
1687 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1689 "The following info documentation is available:\n"
1691 (insert-text-button "Elpher Manual"
1697 'help-echo help-string)
1699 (insert-text-button "Changes introduced by the latest release"
1703 (info "(elpher)News"))
1705 'help-echo help-string))
1708 (concat " (These documents should be available if you have installed Elpher \n"
1709 " using MELPA. Otherwise you may have to install the manual yourself.)\n")
1711 (elpher-restore-pos)))
1713 ;; History page retrieval
1715 (defun elpher-show-history ()
1716 "Show the current contents of elpher's history stack.
1717 Use \\[elpher-show-visited-pages] to see the entire history.
1718 This is rendered using `elpher-get-history-page' via `elpher-type-map'."
1721 (elpher-make-page "Current History Stack"
1722 (elpher-make-special-address 'history))))
1724 (defun elpher-show-visited-pages ()
1725 "Show the all the pages you've visited using Elpher.
1726 Use \\[elpher-show-history] to see just the current history stack.
1727 This is rendered using `elpher-get-visited-pages-page' via `elpher-type-map'."
1730 (elpher-make-page "Elpher Visted Pages"
1731 (elpher-make-special-address 'visited-pages))))
1733 (defun elpher-get-history-page (renderer)
1734 "Getter which displays the history page (RENDERER must be nil)."
1736 (elpher-visit-previous-page)
1737 (error "Command not supported for history page"))
1738 (elpher-display-history-links elpher-history "Current history stack"))
1740 (defun elpher-get-visited-pages-page (renderer)
1741 "Getter which displays the list of visited pages (RENDERER must be nil)."
1743 (elpher-visit-previous-page)
1744 (error "Command not supported for history page"))
1745 (elpher-display-history-links
1746 (seq-filter (lambda (page)
1747 (not (elpher-address-special-p (elpher-page-address page))))
1748 elpher-visited-pages)
1749 "All visited pages"))
1751 (defun elpher-display-history-links (pages title)
1752 "Show all PAGES in an Elpher buffer with a given TITLE."
1753 (let* ((title-line (concat "---- " title " ----"))
1754 (footer-line (make-string (length title-line) ?-)))
1755 (elpher-with-clean-buffer
1756 (insert title-line "\n\n")
1758 (dolist (page pages)
1760 (let ((display-string (elpher-page-display-string page))
1761 (address (elpher-page-address page)))
1762 (elpher-insert-index-record display-string address))))
1763 (insert "No history items found.\n"))
1764 (insert "\n" footer-line "\n"
1765 "Select and entry or press 'u' to return to the previous page.")
1766 (elpher-restore-pos))))
1771 ;; This code allows Elpher to use the standard Emacs bookmarks: `C-x r
1772 ;; m' to add a bookmark, `C-x r l' to list bookmarks (which is where
1773 ;; you can anotate bookmarks!), `C-x r b' to jump to a bookmark, and
1774 ;; so on. See the Bookmarks section in the Emacs info manual for more.
1776 (defvar elpher-bookmark-link nil
1777 "Prefer bookmarking a link or the current page.
1778 Bind this variable dynamically, or set it to t.
1779 If you set it to t, the commands \\[bookmark-set-no-overwrite]
1780 and \\[elpher-set-bookmark-no-overwrite] do the same thing.")
1782 (defun elpher-bookmark-make-record ()
1783 "Return a bookmark record.
1784 If `elpher-bookmark-link' is non-nil and point is on a link button,
1785 return a bookmark record for that link. Otherwise, return a bookmark
1786 record for the current elpher page."
1787 (let* ((button (and elpher-bookmark-link (button-at (point))))
1789 (button-get button 'elpher-page)
1790 elpher-current-page))
1791 (address (elpher-page-address page))
1792 (url (elpher-address-to-url address))
1793 (display-string (elpher-page-display-string page))
1794 (pos (if button nil (point))))
1795 (if (elpher-address-special-p address)
1796 (error "Cannot bookmark %s" display-string)
1798 (defaults . (,display-string))
1801 (handler . elpher-bookmark-jump)))))
1804 (defun elpher-bookmark-jump (bookmark)
1805 "Handler used to open a bookmark using elpher.
1806 The argument BOOKMARK is a bookmark record passed to the function.
1807 This handler is responsible for loading the bookmark in some buffer,
1808 then making that buffer the current buffer. It should not switch
1810 (let* ((url (cdr (assq 'location bookmark)))
1811 (cleaned-url (string-trim url))
1812 (address (elpher-address-from-url cleaned-url))
1813 (page (elpher-make-page cleaned-url address)))
1814 (elpher-with-clean-buffer
1815 (elpher-visit-page page))
1816 (set-buffer (get-buffer elpher-buffer-name))
1819 (defun elpher-bookmark-link ()
1820 "Bookmark the link at point.
1821 To bookmark the current page, use \\[elpher-bookmark-current]."
1823 (let ((elpher-bookmark-link t))
1824 (bookmark-set-no-overwrite)))
1826 (defun elpher-bookmark-current ()
1827 "Bookmark the current page.
1828 To bookmark the link at point use \\[elpher-bookmark-link]."
1830 (call-interactively #'bookmark-set-no-overwrite))
1832 (defun elpher-bookmark-import (file)
1833 "Import legacy Elpher bookmarks file FILE into Emacs bookmarks."
1834 (interactive (list (if (and (boundp 'elpher-bookmarks-file)
1835 (file-readable-p elpher-bookmarks-file))
1836 elpher-bookmarks-file
1837 (read-file-name "Old Elpher bookmarks: "
1838 user-emacs-directory nil t
1839 "elpher-bookmarks"))))
1841 (dolist (bookmark (with-temp-buffer
1842 (insert-file-contents file)
1843 (read (current-buffer))))
1844 (let* ((display-string (car bookmark))
1845 (url (cadr bookmark))
1846 (record `(,display-string
1848 (handler . elpher-bookmark-jump))))
1849 (bookmark-store display-string (cdr record) t)))
1852 (defun elpher-open-bookmarks ()
1853 "Display the current list of elpher bookmarks.
1854 This is just a call to `bookmark-bmenu-list', but we also check for a legacy
1855 bookmark file and offer to import it."
1857 (let ((old-bookmarks-file (or (and (boundp 'elpher-bookmarks-file)
1858 elpher-bookmarks-file)
1859 (locate-user-emacs-file "elpher-bookmarks"))))
1860 (when (and (file-readable-p old-bookmarks-file)
1861 (y-or-n-p (concat "Legacy elpher-bookmarks file \""
1863 "\" found. Import now?")))
1864 (elpher-bookmark-import old-bookmarks-file)
1865 (rename-file old-bookmarks-file (concat old-bookmarks-file "-legacy"))))
1866 (call-interactively #'bookmark-bmenu-list))
1874 (defun elpher-org-export-link (link description format protocol)
1875 "Export a LINK with DESCRIPTION for the given PROTOCOL and FORMAT.
1877 FORMAT is an Org export backend. DESCRIPTION may be nil. PROTOCOL may be one
1878 of gemini, gopher or finger."
1879 (let* ((url (if (equal protocol "elpher")
1880 (string-remove-prefix "elpher:" link)
1881 (format "%s:%s" protocol link)))
1882 (desc (or description url)))
1884 (`gemini (format "=> %s %s" url desc))
1885 (`html (format "<a href=\"%s\">%s</a>" url desc))
1886 (`latex (format "\\href{%s}{%s}" url desc))
1887 (_ (if (not description)
1889 (format "%s (%s)" desc url))))))
1891 (defun elpher-org-store-link ()
1892 "Store link to an `elpher' page in Org."
1893 (when (eq major-mode 'elpher-mode)
1894 (let* ((url (elpher-info-current))
1895 (desc (car elpher-current-page))
1897 ((string-prefix-p "gemini:" url) "gemini")
1898 ((string-prefix-p "gopher:" url) "gopher")
1899 ((string-prefix-p "finger:" url) "finger")
1901 (when (equal "elpher" protocol)
1902 ;; Weird link. Or special inner link?
1903 (setq url (concat "elpher:" url)))
1904 (org-link-store-props :type protocol :link url :description desc)
1907 (defun elpher-org-follow-link (link protocol)
1908 "Visit a LINK for the given PROTOCOL.
1910 PROTOCOL may be one of gemini, gopher or finger. This method also
1911 supports the old protocol elpher, where the link is self-contained."
1912 (let ((url (if (equal protocol "elpher")
1913 (string-remove-prefix "elpher:" link)
1914 (format "%s:%s" protocol link))))
1917 (defun elpher-org-mode-integration ()
1918 "Set up `elpher' integration for `org-mode'."
1919 (org-link-set-parameters
1921 :store #'elpher-org-store-link
1922 :export (lambda (link description format _plist)
1923 (elpher-org-export-link link description format "elpher"))
1924 :follow (lambda (link _arg) (elpher-org-follow-link link "elpher")))
1925 (org-link-set-parameters
1927 :export (lambda (link description format _plist)
1928 (elpher-org-export-link link description format "gemini"))
1929 :follow (lambda (link _arg) (elpher-org-follow-link link "gemini")))
1930 (org-link-set-parameters
1932 :export (lambda (link description format _plist)
1933 (elpher-org-export-link link description format "gopher"))
1934 :follow (lambda (link _arg) (elpher-org-follow-link link "gopher")))
1935 (org-link-set-parameters
1937 :export (lambda (link description format _plist)
1938 (elpher-org-export-link link description format "finger"))
1939 :follow (lambda (link _arg) (elpher-org-follow-link link "finger"))))
1941 (add-hook 'org-mode-hook #'elpher-org-mode-integration)
1946 (defun elpher-browse-url-elpher (url &rest _args)
1947 "Browse URL using Elpher. This function is used by `browse-url'."
1948 (interactive (browse-url-interactive-arg "Elpher URL: "))
1951 ;; Use elpher to open gopher, finger and gemini links
1952 ;; For recent version of `browse-url' package
1953 (if (boundp 'browse-url-default-handlers)
1955 'browse-url-default-handlers
1956 '("^\\(gopher\\|finger\\|gemini\\)://" . elpher-browse-url-elpher))
1957 ;; Patch `browse-url-browser-function' for older ones. The value of
1958 ;; that variable is `browse-url-default-browser' by default, so
1959 ;; that's the function that gets advised.
1960 (advice-add browse-url-browser-function :before-while
1961 (lambda (url &rest _args)
1962 "Handle gemini, gopher, and finger schemes using Elpher."
1963 (let ((scheme (downcase (car (split-string url ":" t)))))
1964 (if (member scheme '("gemini" "gopher" "finger"))
1965 ;; `elpher-go' always returns nil, which will stop the
1966 ;; advice chain here in a before-while
1968 ;; chain must continue, then return t.
1971 ;; Register "gemini://" as a URI scheme so `browse-url' does the right thing
1972 (with-eval-after-load 'thingatpt
1973 (add-to-list 'thing-at-point-uri-schemes "gemini://"))
1977 ;; Make mu4e aware of the gemini world
1978 (setq mu4e~view-beginning-of-url-regexp
1979 "\\(?:https?\\|gopher\\|finger\\|gemini\\)://\\|mailto:")
1983 ;; Let elpher handle gemini, gopher links in eww buffer.
1984 (setq eww-use-browse-url
1985 "\\`mailto:\\|\\(\\`gemini\\|\\`gopher\\|\\`finger\\)://")
1987 ;;; Interactive procedures
1990 (defun elpher-next-link ()
1991 "Move point to the next link on the current page."
1995 (defun elpher-prev-link ()
1996 "Move point to the previous link on the current page."
1998 (backward-button 1))
2000 (defun elpher-follow-current-link ()
2001 "Open the link or url at point."
2006 (defun elpher-go (host-or-url)
2007 "Go to a particular gopher site HOST-OR-URL.
2008 When run interactively HOST-OR-URL is read from the minibuffer."
2009 (interactive "sGopher or Gemini URL: ")
2010 (let* ((cleaned-host-or-url (string-trim host-or-url))
2011 (address (elpher-address-from-url cleaned-host-or-url))
2012 (page (elpher-make-page cleaned-host-or-url address)))
2013 (switch-to-buffer elpher-buffer-name)
2014 (elpher-with-clean-buffer
2015 (elpher-visit-page page))
2018 (defun elpher-go-current ()
2019 "Go to a particular site read from the minibuffer, initialized with the current URL."
2021 (let ((address (elpher-page-address elpher-current-page)))
2022 (let ((url (read-string "Gopher or Gemini URL: "
2023 (unless (elpher-address-special-p address)
2024 (elpher-address-to-url address)))))
2025 (elpher-visit-page (elpher-make-page url (elpher-address-from-url url))))))
2027 (defun elpher-redraw ()
2028 "Redraw current page."
2030 (elpher-visit-page elpher-current-page))
2032 (defun elpher-reload ()
2033 "Reload current page."
2035 (elpher-reload-current-page))
2037 (defun elpher-toggle-tls ()
2038 "Toggle TLS encryption mode for gopher."
2040 (setq elpher-use-tls (not elpher-use-tls))
2042 (if (gnutls-available-p)
2043 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
2044 (setq elpher-use-tls nil)
2045 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
2046 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
2048 (defun elpher-view-raw ()
2049 "View raw server response for current page."
2051 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
2052 (error "This page was not generated by a server")
2053 (elpher-visit-page elpher-current-page
2054 #'elpher-render-raw)))
2056 (defun elpher-back ()
2057 "Go to previous site."
2059 (elpher-visit-previous-page))
2061 (defun elpher-back-to-start ()
2062 "Go all the way back to the start page."
2064 (setq-local elpher-current-page nil)
2065 (setq-local elpher-history nil)
2066 (elpher-visit-page (elpher-make-start-page)))
2068 (defun elpher-download ()
2069 "Download the link at point."
2071 (let ((button (button-at (point))))
2073 (let ((page (button-get button 'elpher-page)))
2074 (if (elpher-address-special-p (elpher-page-address page))
2075 (error "Cannot download %s"
2076 (elpher-page-display-string page))
2077 (elpher-visit-page (button-get button 'elpher-page)
2078 #'elpher-render-download)))
2079 (error "No link selected"))))
2081 (defun elpher-download-current ()
2082 "Download the current page."
2084 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
2085 (error "Cannot download %s"
2086 (elpher-page-display-string elpher-current-page))
2087 (elpher-visit-page (elpher-make-page
2088 (elpher-page-display-string elpher-current-page)
2089 (elpher-page-address elpher-current-page))
2090 #'elpher-render-download
2093 (defun elpher--build-link-map ()
2094 "Build alist mapping link names to destination pages in current buffer."
2095 (let ((link-map nil)
2096 (b (next-button (point-min) t)))
2098 (push (cons (button-label b) b) link-map)
2099 (setq b (next-button (button-start b))))
2102 (defun elpher-jump ()
2103 "Select a directory entry by name. Similar to the info browser (m)enu command."
2105 (let* ((link-map (elpher--build-link-map)))
2107 (let ((key (let ((completion-ignore-case t))
2108 (completing-read "Directory item/link: "
2110 (if (and key (> (length key) 0))
2111 (let ((b (cdr (assoc key link-map))))
2112 (goto-char (button-start b))
2113 (button-activate b)))))))
2115 (defun elpher-root-dir ()
2116 "Visit root of current server."
2118 (let ((address (elpher-page-address elpher-current-page)))
2119 (if (not (elpher-address-special-p address))
2120 (if (or (member (url-filename address) '("/" ""))
2121 (and (elpher-address-gopher-p address)
2122 (= (length (elpher-gopher-address-selector address)) 0)))
2123 (error "Already at root directory of current server")
2124 (let ((address-copy (elpher-address-from-url
2125 (elpher-address-to-url address))))
2126 (setf (url-filename address-copy) "")
2127 (elpher-go (elpher-address-to-url address-copy))))
2128 (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
2130 (defun elpher-info-page (page)
2131 "Display information on PAGE."
2132 (let ((display-string (elpher-page-display-string page))
2133 (address (elpher-page-address page)))
2134 (if (elpher-address-special-p address)
2135 (message "Special page: %s" display-string)
2136 (message "%s" (elpher-address-to-url address)))))
2138 (defun elpher-info-link ()
2139 "Display information on page corresponding to link at point."
2141 (let ((button (button-at (point))))
2143 (elpher-info-page (button-get button 'elpher-page))
2144 (error "No item selected"))))
2146 (defun elpher-info-current ()
2147 "Display information on current page."
2149 (elpher-info-page elpher-current-page))
2151 (defun elpher-copy-page-url (page)
2152 "Copy URL representation of address of PAGE to `kill-ring'."
2153 (let ((address (elpher-page-address page)))
2154 (if (elpher-address-special-p address)
2155 (error (format "Cannot represent %s as URL" (elpher-page-display-string page)))
2156 (let ((url (elpher-address-to-url address)))
2157 (message "Copied \"%s\" to kill-ring/clipboard." url)
2160 (defun elpher-copy-link-url ()
2161 "Copy URL of item at point to `kill-ring'."
2163 (let ((button (button-at (point))))
2165 (elpher-copy-page-url (button-get button 'elpher-page))
2166 (error "No item selected"))))
2168 (defun elpher-copy-current-url ()
2169 "Copy URL of current page to `kill-ring'."
2171 (elpher-copy-page-url elpher-current-page))
2173 (defun elpher-set-gopher-coding-system ()
2174 "Specify an explicit character coding system for gopher selectors."
2176 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
2177 (setq elpher-user-coding-system system)
2179 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
2180 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
2186 (defvar elpher-mode-map
2187 (let ((map (make-sparse-keymap)))
2188 (define-key map (kbd "TAB") 'elpher-next-link)
2189 (define-key map (kbd "<backtab>") 'elpher-prev-link)
2190 (define-key map (kbd "C-M-i") 'elpher-prev-link)
2191 (define-key map (kbd "u") 'elpher-back)
2192 (define-key map (kbd "-") 'elpher-back)
2193 (define-key map (kbd "^") 'elpher-back)
2194 (define-key map [mouse-3] 'elpher-back)
2195 (define-key map (kbd "U") 'elpher-back-to-start)
2196 (define-key map (kbd "g") 'elpher-go)
2197 (define-key map (kbd "o") 'elpher-go-current)
2198 (define-key map (kbd "O") 'elpher-root-dir)
2199 (define-key map (kbd "s") 'elpher-show-history)
2200 (define-key map (kbd "S") 'elpher-show-visited-pages)
2201 (define-key map (kbd "r") 'elpher-redraw)
2202 (define-key map (kbd "R") 'elpher-reload)
2203 (define-key map (kbd "T") 'elpher-toggle-tls)
2204 (define-key map (kbd ".") 'elpher-view-raw)
2205 (define-key map (kbd "d") 'elpher-download)
2206 (define-key map (kbd "D") 'elpher-download-current)
2207 (define-key map (kbd "m") 'elpher-jump)
2208 (define-key map (kbd "i") 'elpher-info-link)
2209 (define-key map (kbd "I") 'elpher-info-current)
2210 (define-key map (kbd "c") 'elpher-copy-link-url)
2211 (define-key map (kbd "C") 'elpher-copy-current-url)
2212 (define-key map (kbd "a") 'elpher-bookmark-link)
2213 (define-key map (kbd "A") 'elpher-bookmark-current)
2214 (define-key map (kbd "B") 'elpher-open-bookmarks)
2215 (define-key map (kbd "!") 'elpher-set-gopher-coding-system)
2216 (define-key map (kbd "F") 'elpher-forget-current-certificate)
2217 (when (fboundp 'evil-define-key*)
2220 (kbd "TAB") 'elpher-next-link
2221 (kbd "C-") 'elpher-follow-current-link
2222 (kbd "C-t") 'elpher-back
2223 (kbd "u") 'elpher-back
2224 (kbd "-") 'elpher-back
2225 (kbd "^") 'elpher-back
2226 [mouse-3] 'elpher-back
2227 (kbd "U") 'elpher-back-to-start
2228 (kbd "g") 'elpher-go
2229 (kbd "o") 'elpher-go-current
2230 (kbd "O") 'elpher-root-dir
2231 (kbd "s") 'elpher-show-history
2232 (kbd "S") 'elpher-show-visited-pages
2233 (kbd "r") 'elpher-redraw
2234 (kbd "R") 'elpher-reload
2235 (kbd "T") 'elpher-toggle-tls
2236 (kbd ".") 'elpher-view-raw
2237 (kbd "d") 'elpher-download
2238 (kbd "D") 'elpher-download-current
2239 (kbd "m") 'elpher-jump
2240 (kbd "i") 'elpher-info-link
2241 (kbd "I") 'elpher-info-current
2242 (kbd "c") 'elpher-copy-link-url
2243 (kbd "C") 'elpher-copy-current-url
2244 (kbd "a") 'elpher-bookmark-link
2245 (kbd "A") 'elpher-bookmark-current
2246 (kbd "B") 'elpher-open-bookmarks
2247 (kbd "!") 'elpher-set-gopher-coding-system
2248 (kbd "F") 'elpher-forget-current-certificate))
2250 "Keymap for gopher client.")
2252 (define-derived-mode elpher-mode special-mode "elpher"
2253 "Major mode for elpher, an elisp gopher client.
2255 This mode is automatically enabled by the interactive
2256 functions which initialize the client, namely
2257 `elpher', and `elpher-go'."
2258 (setq-local elpher--gemini-page-headings nil)
2259 (setq-local elpher-current-page nil)
2260 (setq-local elpher-history nil)
2261 (setq-local elpher-buffer-name (buffer-name))
2262 (setq-local bookmark-make-record-function #'elpher-bookmark-make-record)
2263 (setq-local imenu-create-index-function (lambda () elpher--gemini-page-headings))
2264 (setq-local xterm-color-preserve-properties t))
2266 (when (fboundp 'evil-set-initial-state)
2267 (evil-set-initial-state 'elpher-mode 'motion))
2270 ;;; Main start procedure
2274 (defun elpher (&optional arg)
2275 "Start elpher with default landing page.
2276 The buffer used for Elpher sessions is determined by the value of
2277 ‘elpher-buffer-name’. If there is already an Elpher session active in
2278 that buffer, Emacs will simply switch to it. Otherwise, a new session
2279 will begin. A numeric prefix ARG (as in ‘\\[universal-argument] 42
2280 \\[execute-extended-command] elpher RET’) switches to the session with
2281 that number, creating it if necessary. A non numeric prefix ARG means
2282 to create a new session. Returns the buffer selected (or created)."
2284 (let* ((name (default-value 'elpher-buffer-name))
2285 (buf (cond ((numberp arg)
2286 (get-buffer-create (format "%s<%d>" name arg)))
2288 (generate-new-buffer name))
2290 (get-buffer-create name)))))
2291 (pop-to-buffer-same-window buf)
2292 (unless (buffer-modified-p)
2294 (elpher-visit-page (elpher-make-start-page))
2295 "Started Elpher."))); Otherwise (elpher) evaluates to start page string.
2297 ;;; elpher.el ends here