1 ;;; elpher.el --- A friendly gopher and gemini client -*- lexical-binding:t -*-
3 ;; Copyright (C) 2019 Tim Vaughan
5 ;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
6 ;; Created: 11 April 2019
8 ;; Keywords: comm gopher
9 ;; Homepage: http://thelambdalab.xyz/elpher
10 ;; Package-Requires: ((emacs "26"))
12 ;; This file is not part of GNU Emacs.
14 ;; This program is free software: you can redistribute it and/or modify
15 ;; it under the terms of the GNU General Public License as published by
16 ;; the Free Software Foundation, either version 3 of the License, or
17 ;; (at your option) any later version.
19 ;; This program is distributed in the hope that it will be useful,
20 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
21 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 ;; GNU General Public License for more details.
24 ;; You should have received a copy of the GNU General Public License
25 ;; along with this file. If not, see <http://www.gnu.org/licenses/>.
29 ;; Elpher aims to provide a practical and friendly gopher and gemini
30 ;; client for GNU Emacs. It supports:
32 ;; - intuitive keyboard and mouse-driven browsing,
33 ;; - out-of-the-box compatibility with evil-mode,
34 ;; - clickable web and gopher links *in plain text*,
35 ;; - caching of visited sites,
36 ;; - pleasant and configurable colouring of Gopher directories,
37 ;; - direct visualisation of image files,
38 ;; - a simple bookmark management system,
39 ;; - gopher connections using TLS encryption,
40 ;; - the fledgling Gemini protocol,
41 ;; - the greybeard Finger protocol.
43 ;; To launch Elpher, simply use 'M-x elpher'. This will open a start
44 ;; page containing information on key bindings and suggested starting
45 ;; points for your gopher exploration.
47 ;; Full instructions can be found in the Elpher info manual.
49 ;; Elpher is under active development. Any suggestions for
50 ;; improvements are welcome, and can be made on the official
51 ;; project page, gopher://thelambdalab.xyz/1/projects/elpher/.
74 (defconst elpher-version "2.7.11"
75 "Current version of elpher.")
77 (defconst elpher-margin-width 6
78 "Width of left-hand margin used when rendering indicies.")
80 (defconst elpher-type-map
81 '(((gopher ?0) elpher-get-gopher-page elpher-render-text "txt" elpher-text)
82 ((gopher ?1) elpher-get-gopher-page elpher-render-index "/" elpher-index)
83 ((gopher ?4) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
84 ((gopher ?5) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
85 ((gopher ?7) elpher-get-gopher-query-page elpher-render-index "?" elpher-search)
86 ((gopher ?9) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
87 ((gopher ?g) elpher-get-gopher-page elpher-render-image "img" elpher-image)
88 ((gopher ?p) elpher-get-gopher-page elpher-render-image "img" elpher-image)
89 ((gopher ?I) elpher-get-gopher-page elpher-render-image "img" elpher-image)
90 ((gopher ?d) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
91 ((gopher ?P) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
92 ((gopher ?s) elpher-get-gopher-page elpher-render-download "snd" elpher-binary)
93 ((gopher ?h) elpher-get-gopher-page elpher-render-html "htm" elpher-html)
94 (gemini elpher-get-gemini-page elpher-render-gemini "gem" elpher-gemini)
95 (finger elpher-get-finger-page elpher-render-text "txt" elpher-text)
96 (telnet elpher-get-telnet-page nil "tel" elpher-telnet)
97 (other-url elpher-get-other-url-page nil "url" elpher-other-url)
98 ((special bookmarks) elpher-get-bookmarks-page nil "/" elpher-index)
99 ((special start) elpher-get-start-page nil))
100 "Association list from types to getters, renderers, margin codes and index faces.")
103 ;;; Customization group
108 :group 'applications)
110 ;; General appearance and customizations
112 (defcustom elpher-open-urls-with-eww nil
113 "If non-nil, open URL selectors using eww.
114 Otherwise, use the system browser via the BROWSE-URL function."
117 (defcustom elpher-use-header t
118 "If non-nil, display current page information in buffer header."
121 (defcustom elpher-auto-disengage-TLS nil
122 "If non-nil, automatically disengage TLS following an unsuccessful connection.
123 While enabling this may seem convenient, it is also potentially dangerous as it
124 allows switching from an encrypted channel back to plain text without user input."
127 (defcustom elpher-connection-timeout 5
128 "Specifies the number of seconds to wait for a network connection to time out."
131 (defcustom elpher-filter-ansi-from-text nil
132 "If non-nil, filter ANSI escape sequences from text.
133 The default behaviour is to use the ansi-color package to interpret these
137 (defcustom elpher-gemini-TLS-cert-checks nil
138 "If non-nil, verify gemini server TLS certs using the default security level.
139 Otherwise, certificate verification is disabled.
141 This defaults to off because it is standard practice for Gemini servers
142 to use self-signed certificates, meaning that most servers provide what
143 EMACS considers to be an invalid certificate."
146 (defcustom elpher-gemini-max-fill-width 80
147 "Specify the maximum default width (in columns) of text/gemini documents.
148 The actual width used is the minimum of this value and the window width at
149 the time when the text is rendered."
152 (defcustom elpher-gemini-link-string "→ "
153 "Specify the string used to indicate links when rendering gemini maps.
157 (defcustom elpher-gemini-bullet-string "•"
158 "Specify the string used for bullets when rendering gemini maps."
161 (defcustom elpher-bookmarks-file (locate-user-emacs-file "elpher-bookmarks")
162 "Specify the name of the file where elpher bookmarks will be saved."
165 (defcustom elpher-ipv4-always nil
166 "If non-nil, elpher will always use IPv4 to establish network connections.
167 This can be useful when browsing from a computer that supports IPv6, because
168 some servers which do not support IPv6 can take a long time to time-out."
171 ;; Face customizations
173 (defgroup elpher-faces nil
174 "Elpher face customizations."
177 (defface elpher-index
178 '((t :inherit font-lock-keyword-face))
179 "Face used for directory type directory records.")
183 "Face used for text type directory records.")
186 '((t :inherit default))
187 "Face used for info type directory records.")
189 (defface elpher-image
190 '((t :inherit font-lock-string-face))
191 "Face used for image type directory records.")
193 (defface elpher-search
194 '((t :inherit warning))
195 "Face used for search type directory records.")
198 '((t :inherit font-lock-comment-face))
199 "Face used for html type directory records.")
201 (defface elpher-gemini
202 '((t :inherit font-lock-regexp-grouping-backslash))
203 "Face used for Gemini type directory records.")
205 (defface elpher-other-url
206 '((t :inherit font-lock-comment-face))
207 "Face used for other URL type links records.")
209 (defface elpher-telnet
210 '((t :inherit font-lock-function-name-face))
211 "Face used for telnet type directory records.")
213 (defface elpher-binary
214 '((t :inherit font-lock-doc-face))
215 "Face used for binary type directory records.")
217 (defface elpher-unknown
218 '((t :inherit error))
219 "Face used for directory records with unknown/unsupported types.")
221 (defface elpher-margin-key
223 "Face used for directory margin key.")
225 (defface elpher-margin-brackets
226 '((t :inherit shadow))
227 "Face used for brackets around directory margin key.")
229 (defface elpher-gemini-heading1
230 '((t :inherit bold :height 1.8))
231 "Face used for gemini heading level 1.")
233 (defface elpher-gemini-heading2
234 '((t :inherit bold :height 1.5))
235 "Face used for gemini heading level 2.")
237 (defface elpher-gemini-heading3
238 '((t :inherit bold :height 1.2))
239 "Face used for gemini heading level 3.")
241 (defface elpher-gemini-preformatted
242 '((t :inherit fixed-pitch))
243 "Face used for pre-formatted gemini text blocks.")
250 ;; An elpher "address" object is either a url object or a symbol.
251 ;; Symbol addresses are "special", corresponding to pages generated
252 ;; dynamically for and by elpher. All others represent pages which
253 ;; rely on content retrieved over the network.
255 (defun elpher-address-from-url (url-string)
256 "Create a ADDRESS object corresponding to the given URL-STRING."
257 (let ((data (match-data))) ; Prevent parsing clobbering match data
259 (let ((url (url-generic-parse-url url-string)))
260 (unless (and (not (url-fullness url)) (url-type url))
261 (setf (url-fullness url) t)
262 (setf (url-filename url)
263 (url-unhex-string (url-filename url)))
264 (unless (url-type url)
265 (setf (url-type url) "gopher"))
266 (when (or (equal "gopher" (url-type url))
267 (equal "gophers" (url-type url)))
269 (unless (url-host url)
270 (setf (url-host url) (url-filename url))
271 (setf (url-filename url) ""))
272 (when (or (equal (url-filename url) "")
273 (equal (url-filename url) "/"))
274 (setf (url-filename url) "/1")))
275 (when (equal "gemini" (url-type url))
277 (if (equal (url-filename url) "")
278 (setf (url-filename url) "/"))))
280 (set-match-data data))))
282 (defun elpher-make-gopher-address (type selector host port &optional tls)
283 "Create an ADDRESS object using gopher directory record attributes.
284 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
285 If the optional attribute TLS is non-nil, the address will be marked as
286 requiring gopher-over-TLS."
288 ((equal type ?i) nil)
289 ((and (equal type ?h)
290 (string-prefix-p "URL:" selector))
291 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
293 (elpher-address-from-url
296 ":" (number-to-string port))))
298 (elpher-address-from-url
299 (concat "gopher" (if tls "s" "")
301 ":" (number-to-string port)
305 (defun elpher-make-special-address (type)
306 "Create an ADDRESS object corresponding to the given special address symbol TYPE."
309 (defun elpher-address-to-url (address)
310 "Get string representation of ADDRESS, or nil if ADDRESS is special."
311 (if (elpher-address-special-p address)
313 (url-encode-url (url-recreate-url address))))
315 (defun elpher-address-type (address)
316 "Retrieve type of ADDRESS object.
317 This is used to determine how to retrieve and render the document the
318 address refers to, via the table `elpher-type-map'."
319 (if (symbolp address)
320 (list 'special address)
321 (let ((protocol (url-type address)))
322 (cond ((or (equal protocol "gopher")
323 (equal protocol "gophers"))
325 (if (member (url-filename address) '("" "/"))
327 (string-to-char (substring (url-filename address) 1)))))
328 ((equal protocol "gemini")
330 ((equal protocol "telnet")
332 ((equal protocol "finger")
336 (defun elpher-address-protocol (address)
337 "Retrieve the transport protocol for ADDRESS. This is nil for special addresses."
338 (if (symbolp address)
342 (defun elpher-address-filename (address)
343 "Retrieve the filename component of ADDRESS.
344 For gopher addresses this is a combination of the selector type and selector."
345 (if (symbolp address)
347 (url-filename address)))
349 (defun elpher-address-host (address)
350 "Retrieve host from ADDRESS object."
353 (defun elpher-address-user (address)
354 "Retrieve user from ADDRESS object."
357 (defun elpher-address-port (address)
358 "Retrieve port from ADDRESS object.
359 If no address is defined, returns 0. (This is for compatibility with the URL library.)"
360 (if (symbolp address)
364 (defun elpher-address-special-p (address)
365 "Return non-nil if ADDRESS object is special (e.g. start page, bookmarks page)."
368 (defun elpher-address-gopher-p (address)
369 "Return non-nill if ADDRESS object is a gopher address."
370 (and (not (elpher-address-special-p address))
371 (member (elpher-address-protocol address) '("gopher gophers"))))
373 (defun elpher-gopher-address-selector (address)
374 "Retrieve gopher selector from ADDRESS object."
375 (if (member (url-filename address) '("" "/"))
377 (url-unhex-string (substring (url-filename address) 2))))
382 (defvar elpher-content-cache (make-hash-table :test 'equal))
383 (defvar elpher-pos-cache (make-hash-table :test 'equal))
385 (defun elpher-get-cached-content (address)
386 "Retrieve the cached content for ADDRESS, or nil if none exists."
387 (gethash address elpher-content-cache))
389 (defun elpher-cache-content (address content)
390 "Set the content cache for ADDRESS to CONTENT."
391 (puthash address content elpher-content-cache))
393 (defun elpher-get-cached-pos (address)
394 "Retrieve the cached cursor position for ADDRESS, or nil if none exists."
395 (gethash address elpher-pos-cache))
397 (defun elpher-cache-pos (address pos)
398 "Set the cursor position cache for ADDRESS to POS."
399 (puthash address pos elpher-pos-cache))
404 (defun elpher-make-page (display-string address)
405 "Create a page with DISPLAY-STRING and ADDRESS."
406 (list display-string address))
408 (defun elpher-page-display-string (page)
409 "Retrieve the display string corresponding to PAGE."
412 (defun elpher-page-address (page)
413 "Retrieve the address corresponding to PAGE."
416 (defun elpher-page-set-address (page new-address)
417 "Set the address corresponding to PAGE to NEW-ADDRESS."
418 (setcar (cdr page) new-address))
420 (defvar elpher-current-page nil)
421 (defvar elpher-history nil)
423 (defun elpher-visit-page (page &optional renderer no-history)
424 "Visit PAGE using its own renderer or RENDERER, if non-nil.
425 Additionally, push PAGE onto the stack of previously-visited pages,
426 unless NO-HISTORY is non-nil."
428 (elpher-process-cleanup)
429 (unless (or no-history
430 (equal (elpher-page-address elpher-current-page)
431 (elpher-page-address page)))
432 (push elpher-current-page elpher-history))
433 (setq elpher-current-page page)
434 (let* ((address (elpher-page-address page))
435 (type (elpher-address-type address))
436 (type-record (cdr (assoc type elpher-type-map))))
438 (funcall (car type-record)
442 (elpher-visit-previous-page)
444 (`(gopher ,type-char)
445 (error "Unsupported gopher selector type '%c' for '%s'"
446 type-char (elpher-address-to-url address)))
448 (error "Unsupported address type '%S' for '%s'"
449 other (elpher-address-to-url address)))))))
451 (defun elpher-visit-previous-page ()
452 "Visit the previous page in the history."
453 (let ((previous-page (pop elpher-history)))
455 (elpher-visit-page previous-page nil t)
456 (error "No previous page"))))
458 (defun elpher-reload-current-page ()
459 "Reload the current page, discarding any existing cached content."
460 (elpher-cache-content (elpher-page-address elpher-current-page) nil)
461 (elpher-visit-page elpher-current-page))
463 (defun elpher-save-pos ()
464 "Save the current position of point to the current page."
465 (when elpher-current-page
466 (elpher-cache-pos (elpher-page-address elpher-current-page) (point))))
468 (defun elpher-restore-pos ()
469 "Restore the position of point to that cached in the current page."
470 (let ((pos (elpher-get-cached-pos (elpher-page-address elpher-current-page))))
473 (goto-char (point-min)))))
476 ;;; Buffer preparation
479 (defun elpher-update-header ()
480 "If `elpher-use-header' is true, display current page info in window header."
481 (if elpher-use-header
482 (let* ((display-string (elpher-page-display-string elpher-current-page))
483 (address (elpher-page-address elpher-current-page))
484 (tls-string (if (and (not (elpher-address-special-p address))
485 (member (elpher-address-protocol address)
486 '("gophers" "gemini")))
489 (header (concat display-string
490 (propertize tls-string 'face 'bold))))
491 (setq header-line-format header))))
493 (defmacro elpher-with-clean-buffer (&rest args)
494 "Evaluate ARGS with a clean *elpher* buffer as current."
495 (list 'with-current-buffer "*elpher*"
497 (append (list 'let '((inhibit-read-only t))
498 '(setq-local network-security-level
499 (default-value 'network-security-level))
501 '(elpher-update-header))
504 (defun elpher-buffer-message (string &optional line)
505 "Replace first line in elpher buffer with STRING.
506 If LINE is non-nil, replace that line instead."
507 (with-current-buffer "*elpher*"
508 (let ((inhibit-read-only t))
509 (goto-char (point-min))
512 (let ((data (match-data)))
515 (re-search-forward "^.*$")
516 (replace-match string))
517 (set-match-data data))))))
523 (defvar elpher-user-coding-system nil
524 "User-specified coding system to use for decoding text responses.")
526 (defun elpher-decode (string)
527 "Decode STRING using autodetected or user-specified coding system."
528 (decode-coding-string string
529 (if elpher-user-coding-system
530 elpher-user-coding-system
531 (detect-coding-string string t))))
533 (defun elpher-preprocess-text-response (string)
534 "Preprocess text selector response contained in STRING.
535 This involes decoding the character representation, and clearing
536 away CRs and any terminating period."
537 (elpher-decode (replace-regexp-in-string "\n\.\n$" "\n"
538 (replace-regexp-in-string "\r" "" string))))
541 ;;; Network error reporting
544 (defun elpher-network-error (address error)
545 "Display ERROR message following unsuccessful negotiation with ADDRESS.
546 ERROR can be either an error object or a string."
547 (elpher-with-clean-buffer
548 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
549 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
550 (if (stringp error) error (error-message-string error)) "\n"
551 (propertize "\n----------------\n\n" 'face 'error)
552 "Press 'u' to return to the previous page.")))
554 ;;; General network communication
556 (defun elpher-get-host-response (address default-port query-string response-processor
557 &optional use-tls force-ipv4)
558 (if (and use-tls (not (gnutls-available-p)))
559 (error "Use of TLS requires Emacs to be compiled with GNU TLS support")
560 (unless (< (elpher-address-port address) 65536)
561 (error "Cannot establish network connection: port number > 65536"))
562 (when (and (eq use-tls 'gemini) (not elpher-gemini-TLS-cert-checks))
563 (setq-local network-security-level 'low))
565 (let* ((kill-buffer-query-functions nil)
566 (port (elpher-address-port address))
567 (host (elpher-address-host address))
568 (response-string-parts nil)
571 (proc (make-network-process :name "elpher-process"
573 :family (and force-ipv4 'ipv4)
574 :service (if (> port 0) port default-port)
581 (cons 'gnutls-x509pki
582 (gnutls-boot-parameters
583 :type 'gnutls-x509pki
585 (timer (run-at-time elpher-connection-timeout nil
587 (elpher-process-cleanup)
589 ; Try again with IPv4
591 (message "Connection timed out. Retrying with IPv4.")
592 (elpher-get-host-response address default-port
597 (not (eq use-tls 'gemini))
598 (or elpher-auto-disengage-TLS
600 "TLS connetion failed. Disable TLS mode and retry? ")))
601 (setq elpher-use-tls nil)
602 (elpher-get-host-response address default-port
607 (elpher-network-error address "Connection time-out.")))))))
608 (setq elpher-network-timer timer)
609 (elpher-buffer-message (concat "Connecting to " host "..."))
610 (set-process-filter proc
611 (lambda (_proc string)
615 (setq bytes-received (+ bytes-received (length string)))
616 (let ((new-hkbytes-received (/ bytes-received 102400)))
617 (when (> new-hkbytes-received hkbytes-received)
618 (setq hkbytes-received new-hkbytes-received)
619 (elpher-buffer-message
621 (number-to-string (/ hkbytes-received 10.0))
624 (setq response-string-parts
625 (cons string response-string-parts))))
626 (set-process-sentinel proc
629 (cancel-timer timer))
630 (condition-case the-error
632 ((string-prefix-p "open" event) ; request URL
633 (elpher-buffer-message
634 (concat "Connected to " host ". Receiving data...\n"))
635 (let ((inhibit-eol-conversion t))
636 (process-send-string proc query-string)))
637 ((string-prefix-p "deleted" event)) ; do nothing
638 ((and (not response-string-parts)
639 (not (or elpher-ipv4-always force-ipv4)))
640 ; Try again with IPv4
641 (message "Connection failed. Retrying with IPv4.")
642 (elpher-get-host-response address default-port
646 (response-string-parts
647 (elpher-with-clean-buffer
648 (insert "Data received. Rendering..."))
649 (funcall response-processor
650 (apply #'concat (reverse response-string-parts)))
651 (elpher-restore-pos))
653 (error "No response from server.")))
655 (elpher-network-error address the-error))))))
657 (error "Error initiating connection to server")))))
661 ;;; Gopher selector retrieval
664 (defvar elpher-network-timer nil
665 "Timer used for network connections.")
667 (defun elpher-process-cleanup ()
668 "Immediately shut down any extant elpher process and timers."
669 (let ((p (get-process "elpher-process")))
670 (if p (delete-process p)))
671 (if (timerp elpher-network-timer)
672 (cancel-timer elpher-network-timer)))
674 (defvar elpher-use-tls nil
675 "If non-nil, use TLS to communicate with gopher servers.")
677 (defun elpher-get-gopher-response (address renderer)
678 (elpher-get-host-response address 70
679 (concat (elpher-gopher-address-selector address) "\r\n")
681 (or (string= (elpher-address-protocol address) "gophers")
684 (defun elpher-get-gopher-page (renderer)
685 "Getter function for gopher pages.
686 The RENDERER procedure is used to display the contents of the page
687 once they are retrieved from the gopher server."
688 (let* ((address (elpher-page-address elpher-current-page))
689 (content (elpher-get-cached-content address)))
690 (if (and content (funcall renderer nil))
691 (elpher-with-clean-buffer
693 (elpher-restore-pos))
694 (elpher-with-clean-buffer
695 (insert "LOADING... (use 'u' to cancel)\n"))
696 (condition-case the-error
697 (elpher-get-gopher-response address renderer)
699 (elpher-network-error address the-error))))))
703 (defun elpher-insert-index (string)
704 "Insert the index corresponding to STRING into the current buffer."
705 ;; Should be able to split directly on CRLF, but some non-conformant
706 ;; LF-only servers sadly exist, hence the following.
707 (let ((str-processed (elpher-preprocess-text-response string)))
708 (dolist (line (split-string str-processed "\n"))
710 (unless (= (length line) 0)
711 (let* ((type (elt line 0))
712 (fields (split-string (substring line 1) "\t"))
713 (display-string (elt fields 0))
714 (selector (elt fields 1))
715 (host (elt fields 2))
716 (port (if (elt fields 3)
717 (string-to-number (elt fields 3))
719 (address (elpher-make-gopher-address type selector host port)))
720 (elpher-insert-index-record display-string address)))))))
722 (defun elpher-insert-margin (&optional type-name)
723 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
726 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
728 (propertize "[" 'face 'elpher-margin-brackets)
729 (propertize type-name 'face 'elpher-margin-key)
730 (propertize "]" 'face 'elpher-margin-brackets))))
732 (insert (make-string elpher-margin-width ?\s))))
734 (defun elpher--page-button-help (_window buffer pos)
735 "Function called by Emacs to generate mouse-over text.
736 The arguments specify the BUFFER and the POS within the buffer of the item
737 for which help is required. The function returns the help to be
738 displayed. The _WINDOW argument is currently unused."
739 (with-current-buffer buffer
740 (let ((button (button-at pos)))
742 (let* ((page (button-get button 'elpher-page))
743 (address (elpher-page-address page)))
744 (format "mouse-1, RET: open '%s'" (if (elpher-address-special-p address)
746 (elpher-address-to-url address))))))))
748 (defun elpher-insert-index-record (display-string &optional address)
749 "Function to insert an index record into the current buffer.
750 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
751 If ADDRESS is not supplied or nil the record is rendered as an
753 (let* ((type (if address (elpher-address-type address) nil))
754 (type-map-entry (cdr (assoc type elpher-type-map))))
756 (let* ((margin-code (elt type-map-entry 2))
757 (face (elt type-map-entry 3))
758 (filtered-display-string (ansi-color-filter-apply display-string))
759 (page (elpher-make-page filtered-display-string address)))
760 (elpher-insert-margin margin-code)
761 (insert-text-button filtered-display-string
764 'action #'elpher-click-link
766 'help-echo #'elpher--page-button-help))
769 (elpher-insert-margin)
770 (let ((propertized-display-string
771 (propertize display-string 'face 'elpher-info)))
772 (insert (elpher-process-text-for-display propertized-display-string))))
773 (`(gopher ,selector-type) ;; Unknown
774 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
775 (insert (propertize display-string
776 'face 'elpher-unknown)))))
779 (defun elpher-click-link (button)
780 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
781 (let ((page (button-get button 'elpher-page)))
782 (elpher-visit-page page)))
784 (defun elpher-render-index (data &optional _mime-type-string)
785 "Render DATA as an index. MIME-TYPE-STRING is unused."
786 (elpher-with-clean-buffer
789 (elpher-insert-index data)
790 (elpher-cache-content (elpher-page-address elpher-current-page)
795 (defconst elpher-url-regex
796 "\\([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\-_~?/@|#]\\)?\\)?"
797 "Regexp used to locate and buttinofy URLs in text files loaded by elpher.")
799 (defun elpher-buttonify-urls (string)
800 "Turn substrings which look like urls in STRING into clickable buttons."
803 (goto-char (point-min))
804 (while (re-search-forward elpher-url-regex nil t)
805 (let ((page (elpher-make-page (substring-no-properties (match-string 0))
806 (elpher-address-from-url (match-string 0)))))
807 (make-text-button (match-beginning 0)
810 'action #'elpher-click-link
812 'help-echo #'elpher--page-button-help
816 (defconst elpher-ansi-regex "\x1b\\[[^m]*m"
817 "Wildly incomplete regexp used to strip out some troublesome ANSI escape sequences.")
819 (defun elpher-process-text-for-display (string)
820 "Perform any desired processing of STRING prior to display as text.
821 Currently includes buttonifying URLs and processing ANSI escape codes."
822 (elpher-buttonify-urls (if elpher-filter-ansi-from-text
823 (ansi-color-filter-apply string)
824 (ansi-color-apply string))))
826 (defun elpher-render-text (data &optional _mime-type-string)
827 "Render DATA as text. MIME-TYPE-STRING is unused."
828 (elpher-with-clean-buffer
831 (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
832 (elpher-cache-content
833 (elpher-page-address elpher-current-page)
838 (defun elpher-render-image (data &optional _mime-type-string)
839 "Display DATA as image. MIME-TYPE-STRING is unused."
842 (if (display-images-p)
844 (let ((image (create-image
847 (elpher-with-clean-buffer
849 (elpher-restore-pos))))
850 (elpher-render-download data))))
852 ;; Search retrieval and rendering
854 (defun elpher-get-gopher-query-page (renderer)
855 "Getter for gopher addresses requiring input.
856 The response is rendered using the rendering function RENDERER."
857 (let* ((address (elpher-page-address elpher-current-page))
858 (content (elpher-get-cached-content address))
860 (if (and content (funcall renderer nil))
861 (elpher-with-clean-buffer
864 (message "Displaying cached search results. Reload to perform a new search."))
866 (let* ((query-string (read-string "Query: "))
867 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
868 (search-address (elpher-make-gopher-address ?1
870 (elpher-address-host address)
871 (elpher-address-port address)
872 (equal (elpher-address-type address) "gophers"))))
875 (elpher-with-clean-buffer
876 (insert "LOADING RESULTS... (use 'u' to cancel)"))
877 (elpher-get-gopher-response search-address renderer))
879 (elpher-visit-previous-page))))))
881 ;; Raw server response rendering
883 (defun elpher-render-raw (data &optional mime-type-string)
884 "Display raw DATA in buffer. MIME-TYPE-STRING is also displayed if provided."
887 (elpher-with-clean-buffer
888 (when mime-type-string
889 (insert "MIME type specified by server: '" mime-type-string "'\n"))
891 (goto-char (point-min)))
892 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
894 ;; File save "rendering"
896 (defun elpher-render-download (data &optional _mime-type-string)
897 "Save DATA to file. MIME-TYPE-STRING is unused."
900 (let* ((address (elpher-page-address elpher-current-page))
901 (selector (if (elpher-address-gopher-p address)
902 (elpher-gopher-address-selector address)
903 (elpher-address-filename address))))
904 (elpher-visit-previous-page) ; Do first in case of non-local exits.
905 (let* ((filename-proposal (file-name-nondirectory selector))
906 (filename (read-file-name "Download complete. Save file as: "
908 (if (> (length filename-proposal) 0)
911 (let ((coding-system-for-write 'binary))
912 (with-temp-file filename
914 (message (format "Saved to file %s." filename))))))
918 (defun elpher-render-html (data &optional _mime-type-string)
919 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
920 (elpher-with-clean-buffer
923 (let ((dom (with-temp-buffer
925 (libxml-parse-html-region (point-min) (point-max)))))
926 (shr-insert-document dom)))))
928 ;; Gemini page retrieval
930 (defvar elpher-gemini-redirect-chain)
932 (defun elpher-get-gemini-response (address renderer)
933 (elpher-get-host-response address 1965
934 (concat (elpher-address-to-url address) "\r\n")
935 (lambda (response-string)
936 (elpher-process-gemini-response response-string renderer))
939 (defun elpher-parse-gemini-response (response)
940 "Parse the RESPONSE string and return a list of components.
941 The list is of the form (code meta body). A response of nil implies
942 that the response was malformed."
943 (let ((header-end-idx (string-match "\r\n" response)))
945 (let ((header (string-trim (substring response 0 header-end-idx)))
946 (body (substring response (+ header-end-idx 2))))
947 (if (>= (length header) 2)
948 (let ((code (substring header 0 2))
949 (meta (string-trim (substring header 2))))
950 (list code meta body))
951 (error "Malformed response: No response status found in header %s" header)))
952 (error "Malformed response: No CRLF-delimited header found in response %s" response))))
954 (defun elpher-process-gemini-response (response-string renderer)
955 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
956 (let ((response-components (elpher-parse-gemini-response response-string)))
957 (let ((response-code (elt response-components 0))
958 (response-meta (elt response-components 1))
959 (response-body (elt response-components 2)))
960 (pcase (elt response-code 0)
962 (elpher-with-clean-buffer
963 (insert "Gemini server is requesting input."))
964 (let* ((query-string (read-string (concat response-meta ": ")))
965 (query-address (seq-copy (elpher-page-address elpher-current-page)))
966 (old-fname (url-filename query-address)))
967 (setf (url-filename query-address)
968 (concat old-fname "?" (url-build-query-string `((,query-string)))))
969 (elpher-get-gemini-response query-address renderer)))
970 (?2 ; Normal response
971 (funcall renderer response-body response-meta))
973 (message "Following redirect to %s" response-meta)
974 (if (>= (length elpher-gemini-redirect-chain) 5)
975 (error "More than 5 consecutive redirects followed"))
976 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
977 (if (member redirect-address elpher-gemini-redirect-chain)
978 (error "Redirect loop detected"))
979 (if (not (string= (elpher-address-protocol redirect-address)
981 (error "Server tried to automatically redirect to non-gemini URL: %s"
983 (elpher-page-set-address elpher-current-page redirect-address)
984 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
985 (elpher-get-gemini-response redirect-address renderer)))
986 (?4 ; Temporary failure
987 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
988 response-code response-meta))
989 (?5 ; Permanent failure
990 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
991 response-code response-meta))
992 (?6 ; Client certificate required
993 (error "Gemini server requires client certificate (unsupported at this time)"))
995 (error "Gemini server response unknown: %s %s"
996 response-code response-meta))))))
998 (defun elpher-get-gemini-page (renderer)
999 "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
1000 (let* ((address (elpher-page-address elpher-current-page))
1001 (content (elpher-get-cached-content address)))
1002 (condition-case the-error
1003 (if (and content (funcall renderer nil))
1004 (elpher-with-clean-buffer
1006 (elpher-restore-pos))
1007 (elpher-with-clean-buffer
1008 (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
1009 (setq elpher-gemini-redirect-chain nil)
1010 (elpher-get-gemini-response address renderer))
1012 (elpher-network-error address the-error)))))
1015 (defun elpher-render-gemini (body &optional mime-type-string)
1016 "Render gemini response BODY with rendering MIME-TYPE-STRING."
1019 (let* ((mime-type-string* (if (or (not mime-type-string)
1020 (string-empty-p mime-type-string))
1021 "text/gemini; charset=utf-8"
1023 (mime-type-split (split-string mime-type-string* ";" t))
1024 (mime-type (string-trim (car mime-type-split)))
1025 (parameters (mapcar (lambda (s)
1026 (let ((key-val (split-string s "=")))
1027 (list (downcase (string-trim (car key-val)))
1028 (downcase (string-trim (cadr key-val))))))
1029 (cdr mime-type-split))))
1030 (when (string-prefix-p "text/" mime-type)
1031 (setq body (decode-coding-string
1033 (if (assoc "charset" parameters)
1034 (intern (cadr (assoc "charset" parameters)))
1036 (setq body (replace-regexp-in-string "\r" "" body)))
1038 ((or "text/gemini" "")
1039 (elpher-render-gemini-map body parameters))
1041 (elpher-render-html body))
1042 ((pred (string-prefix-p "text/"))
1043 (elpher-render-gemini-plain-text body parameters))
1044 ((pred (string-prefix-p "image/"))
1045 (elpher-render-image body))
1047 (elpher-render-download body))))))
1049 (defun elpher-gemini-get-link-url (link-line)
1050 "Extract the url portion of LINK-LINE, a gemini map file link line.
1051 Returns nil in the event that the contents of the line following the
1052 => prefix are empty."
1053 (let ((l (split-string (substring link-line 2))))
1055 (string-trim (elt l 0))
1058 (defun elpher-gemini-get-link-display-string (link-line)
1059 "Extract the display string portion of LINK-LINE, a gemini map file link line.
1060 Returns the url portion in the event that the display-string portion is empty."
1061 (let* ((rest (string-trim (elt (split-string link-line "=>") 1)))
1062 (idx (string-match "[ \t]" rest)))
1063 (string-trim (if idx
1064 (substring rest (+ idx 1))
1067 (defun elpher-collapse-dot-sequences (filename)
1068 "Collapse dot sequences in FILENAME.
1069 For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
1070 (let* ((path (split-string filename "/"))
1071 (path-reversed-normalized
1072 (seq-reduce (lambda (a b)
1073 (cond ((and a (equal b "..") (cdr a)))
1074 ((and (not a) (equal b "..")) a) ;leading .. are dropped
1078 (string-join (reverse path-reversed-normalized) "/")))
1080 (defun elpher-address-from-gemini-url (url)
1081 "Extract address from URL with defaults as per gemini map files."
1082 (let ((address (url-generic-parse-url url))
1083 (current-address (elpher-page-address elpher-current-page)))
1084 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
1085 (setf (url-fullness address) t)
1086 (if (url-host address) ;if there is an explicit host, filenames are absolute
1087 (if (string-empty-p (url-filename address))
1088 (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
1089 (setf (url-host address) (url-host current-address))
1090 (setf (url-port address) (url-port current-address))
1091 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
1092 (setf (url-filename address)
1093 (concat (file-name-directory (url-filename current-address))
1094 (url-filename address)))))
1095 (unless (url-type address)
1096 (setf (url-type address) "gemini"))
1097 (if (equal (url-type address) "gemini")
1098 (setf (url-filename address)
1099 (elpher-collapse-dot-sequences (url-filename address)))))
1102 (defun elpher-gemini-insert-link (link-line)
1103 "Insert link described by LINK-LINE into a text/gemini document."
1104 (let* ((url (elpher-gemini-get-link-url link-line))
1105 (display-string (elpher-gemini-get-link-display-string link-line))
1106 (address (elpher-address-from-gemini-url url))
1107 (type (if address (elpher-address-type address) nil))
1108 (type-map-entry (cdr (assoc type elpher-type-map))))
1109 (when display-string
1110 (insert elpher-gemini-link-string)
1112 (let* ((face (elt type-map-entry 3))
1113 (filtered-display-string (ansi-color-filter-apply display-string))
1114 (page (elpher-make-page filtered-display-string address)))
1115 (insert-text-button filtered-display-string
1118 'action #'elpher-click-link
1120 'help-echo #'elpher--page-button-help))
1121 (insert (propertize display-string 'face 'elpher-unknown)))
1124 (defun elpher-gemini-insert-header (header-line)
1125 "Insert header described by HEADER-LINE into a text/gemini document.
1126 The gemini map file line describing the header is given
1128 (when (string-match "^\\(#+\\)[ \t]*" header-line)
1129 (let ((level (length (match-string 1 header-line)))
1130 (header (substring header-line (match-end 0))))
1131 (unless (display-graphic-p)
1132 (insert (make-string level ?#) " "))
1133 (insert (propertize header 'face
1135 (1 'elpher-gemini-heading1)
1136 (2 'elpher-gemini-heading2)
1137 (3 'elpher-gemini-heading3)
1141 (defun elpher-gemini-insert-text (text-line)
1142 "Insert a plain non-preformatted TEXT-LINE into a text/gemini document.
1143 This function uses Emacs' auto-fill to wrap text sensibly to a maximum
1144 width defined by elpher-gemini-max-fill-width."
1145 (string-match "\\(^[ \t]*\\)\\(\*[ \t]+\\|>[ \t]*\\)?" text-line)
1146 (let* ((processed-text-line (if (match-string 2 text-line)
1148 (replace-regexp-in-string "\*"
1149 elpher-gemini-bullet-string
1150 (match-string 0 text-line))
1151 (substring text-line (match-end 0)))
1153 (adaptive-fill-mode nil)
1154 (fill-prefix (if (match-string 2 text-line)
1155 (replace-regexp-in-string "[>\*]" " " (match-string 0 text-line))
1157 (insert (elpher-process-text-for-display processed-text-line))
1160 (defun elpher-render-gemini-map (data _parameters)
1161 "Render DATA as a gemini map file, PARAMETERS is currently unused."
1162 (elpher-with-clean-buffer
1163 (let ((preformatted nil))
1165 (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))
1166 (dolist (line (split-string data "\n"))
1168 ((string-prefix-p "```" line) (setq preformatted (not preformatted)))
1169 (preformatted (insert (elpher-process-text-for-display
1170 (propertize line 'face 'elpher-gemini-preformatted))
1172 ((string-prefix-p "=>" line) (elpher-gemini-insert-link line))
1173 ((string-prefix-p "#" line) (elpher-gemini-insert-header line))
1174 (t (elpher-gemini-insert-text line)))))
1175 (elpher-cache-content
1176 (elpher-page-address elpher-current-page)
1179 (defun elpher-render-gemini-plain-text (data _parameters)
1180 "Render DATA as plain text file. PARAMETERS is currently unused."
1181 (elpher-with-clean-buffer
1182 (insert (elpher-process-text-for-display data))
1183 (elpher-cache-content
1184 (elpher-page-address elpher-current-page)
1187 ;; Finger page connection
1189 (defun elpher-get-finger-page (renderer &optional force-ipv4)
1190 "Opens a finger connection to the current page address.
1191 The result is rendered using RENDERER. When the optional argument
1192 FORCE-IPV4 or the variable `elpher-ipv4-always' are non-nil, the
1193 IPv4 address returned by a DNS lookup will be used explicitly in
1194 making the connection."
1195 (let* ((address (elpher-page-address elpher-current-page))
1196 (content (elpher-get-cached-content address)))
1197 (if (and content (funcall renderer nil))
1198 (elpher-with-clean-buffer
1200 (elpher-restore-pos))
1201 (elpher-with-clean-buffer
1202 (insert "LOADING... (use 'u' to cancel)\n"))
1203 (condition-case the-error
1204 (let* ((kill-buffer-query-functions nil)
1205 (user (let ((filename (elpher-address-filename address)))
1206 (if (> (length filename) 1)
1207 (substring filename 1)
1208 (elpher-address-user address)))))
1209 (elpher-get-host-response address 79
1210 (concat user "\r\n")
1213 (elpher-network-error address the-error))))))
1216 ;; Other URL page opening
1218 (defun elpher-get-other-url-page (renderer)
1219 "Getter which attempts to open the URL specified by the current page (RENDERER must be nil)."
1221 (elpher-visit-previous-page)
1222 (error "Command not supported for general URLs"))
1223 (let* ((address (elpher-page-address elpher-current-page))
1224 (url (elpher-address-to-url address)))
1226 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1227 (message "Opening URL...")
1228 (if elpher-open-urls-with-eww
1230 (browse-url url)))))
1232 ;; Telnet page connection
1234 (defun elpher-get-telnet-page (renderer)
1235 "Opens a telnet connection to the current page address (RENDERER must be nil)."
1237 (elpher-visit-previous-page)
1238 (error "Command not supported for telnet URLs"))
1239 (let* ((address (elpher-page-address elpher-current-page))
1240 (host (elpher-address-host address))
1241 (port (elpher-address-port address)))
1242 (elpher-visit-previous-page)
1247 ;; Start page page retrieval
1249 (defun elpher-get-start-page (renderer)
1250 "Getter which displays the start page (RENDERER must be nil)."
1252 (elpher-visit-previous-page)
1253 (error "Command not supported for start page"))
1254 (elpher-with-clean-buffer
1255 (insert " --------------------------------------------\n"
1256 " Elpher Gopher and Gemini Client \n"
1257 " version " elpher-version "\n"
1258 " --------------------------------------------\n"
1260 "Default bindings:\n"
1262 " - TAB/Shift-TAB: next/prev item on current page\n"
1263 " - RET/mouse-1: open item under cursor\n"
1264 " - m: select an item on current page by name (autocompletes)\n"
1265 " - u/mouse-3/U: return to previous page or to the start page\n"
1266 " - o/O: visit different selector or the root menu of the current server\n"
1267 " - g: go to a particular address (gopher, gemini, finger)\n"
1268 " - d/D: download item under cursor or current page\n"
1269 " - i/I: info on item under cursor or current page\n"
1270 " - c/C: copy URL representation of item under cursor or current page\n"
1271 " - a/A: bookmark the item under cursor or current page\n"
1272 " - x/X: remove bookmark for item under cursor or current page\n"
1273 " - B: visit the bookmarks page\n"
1274 " - r: redraw current page (using cached contents if available)\n"
1275 " - R: reload current page (regenerates cache)\n"
1276 " - S: set character coding system for gopher (default is to autodetect)\n"
1277 " - T: toggle TLS gopher mode\n"
1278 " - .: display the raw server response for the current page\n"
1280 "Start your exploration of gopher space and gemini:\n")
1281 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1282 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1283 (elpher-insert-index-record "Project Gemini home page"
1284 (elpher-address-from-url "gemini://gemini.circumlunar.space/"))
1286 "Alternatively, select a search engine and enter some search terms:\n")
1287 (elpher-insert-index-record "Gopher Search Engine (Veronica-2)"
1288 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1289 (elpher-insert-index-record "Gemini Search Engine (GUS)"
1290 (elpher-address-from-url "gemini://gus.guru/search"))
1292 "This page contains your bookmarked sites (also visit with B):\n")
1293 (elpher-insert-index-record "Your Bookmarks" 'bookmarks)
1295 "For Elpher release news or to leave feedback, visit:\n")
1296 (elpher-insert-index-record "The Elpher Project Page"
1297 (elpher-make-gopher-address ?1
1303 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1304 (insert-text-button "Elpher info manual"
1310 'help-echo help-string))
1311 (insert " for the full documentation. **\n")
1313 (concat " (This should be available if you have installed Elpher using\n"
1314 " MELPA. Otherwise you will have to install the manual yourself.)\n")
1316 (elpher-restore-pos)))
1318 ;; Bookmarks page page retrieval
1320 (defun elpher-get-bookmarks-page (renderer)
1321 "Getter to load and display the current bookmark list (RENDERER must be nil)."
1323 (elpher-visit-previous-page)
1324 (error "Command not supported for bookmarks page"))
1325 (elpher-with-clean-buffer
1326 (insert "---- Bookmark list ----\n\n")
1327 (let ((bookmarks (elpher-load-bookmarks)))
1329 (dolist (bookmark bookmarks)
1330 (let ((display-string (elpher-bookmark-display-string bookmark))
1331 (address (elpher-address-from-url (elpher-bookmark-url bookmark))))
1332 (elpher-insert-index-record display-string address)))
1333 (insert "No bookmarks found.\n")))
1334 (insert "\n-----------------------\n"
1336 "- u: return to previous page\n"
1337 "- x: delete selected bookmark\n"
1338 "- a: rename selected bookmark\n"
1340 "Bookmarks are stored in the file ")
1341 (let ((filename elpher-bookmarks-file)
1342 (help-string "RET,mouse-1: Open bookmarks file in new buffer for editing."))
1343 (insert-text-button filename
1347 (find-file filename))
1349 'help-echo help-string))
1351 (elpher-restore-pos)))
1357 (defun elpher-make-bookmark (display-string url)
1358 "Make an elpher bookmark.
1359 DISPLAY-STRING determines how the bookmark will appear in the
1360 bookmark list, while URL is the url of the entry."
1361 (list display-string url))
1363 (defun elpher-bookmark-display-string (bookmark)
1364 "Get the display string of BOOKMARK."
1367 (defun elpher-set-bookmark-display-string (bookmark display-string)
1368 "Set the display string of BOOKMARK to DISPLAY-STRING."
1369 (setcar bookmark display-string))
1371 (defun elpher-bookmark-url (bookmark)
1372 "Get the address for BOOKMARK."
1375 (defun elpher-save-bookmarks (bookmarks)
1376 "Record the bookmark list BOOKMARKS to the user's bookmark file.
1377 Beware that this completely replaces the existing contents of the file."
1378 (with-temp-file elpher-bookmarks-file
1380 (insert "; Elpher bookmarks file\n\n"
1381 "; Bookmarks are stored as a list of (label URL) items.\n"
1382 "; Feel free to edit by hand, but take care to ensure\n"
1383 "; the list structure remains intact.\n\n")
1384 (pp bookmarks (current-buffer))))
1386 (defun elpher-load-bookmarks ()
1387 "Get the list of bookmarks from the users's bookmark file."
1391 (insert-file-contents elpher-bookmarks-file)
1392 (goto-char (point-min))
1393 (read (current-buffer))))))
1394 (if (and bookmarks (listp (cadar bookmarks)))
1396 (message "Reading old bookmark file. (Will be updated on write.)")
1397 (mapcar (lambda (old-bm)
1399 (elpher-address-to-url (apply #'elpher-make-gopher-address
1404 (defun elpher-add-address-bookmark (address display-string)
1405 "Save a bookmark for ADDRESS with label DISPLAY-STRING.)))
1406 If ADDRESS is already bookmarked, update the label only."
1407 (let ((bookmarks (elpher-load-bookmarks))
1408 (url (elpher-address-to-url address)))
1409 (let ((existing-bookmark (rassoc (list url) bookmarks)))
1410 (if existing-bookmark
1411 (elpher-set-bookmark-display-string existing-bookmark display-string)
1412 (push (elpher-make-bookmark display-string url) bookmarks)))
1413 (elpher-save-bookmarks bookmarks)))
1415 (defun elpher-remove-address-bookmark (address)
1416 "Remove any bookmark to ADDRESS."
1417 (let ((url (elpher-address-to-url address)))
1418 (elpher-save-bookmarks
1419 (seq-filter (lambda (bookmark)
1420 (not (equal (elpher-bookmark-url bookmark) url)))
1421 (elpher-load-bookmarks)))))
1423 ;;; Interactive procedures
1426 (defun elpher-next-link ()
1427 "Move point to the next link on the current page."
1431 (defun elpher-prev-link ()
1432 "Move point to the previous link on the current page."
1434 (backward-button 1))
1436 (defun elpher-follow-current-link ()
1437 "Open the link or url at point."
1441 (defun elpher-go (host-or-url)
1442 "Go to a particular gopher site HOST-OR-URL.
1443 When run interactively HOST-OR-URL is read from the minibuffer."
1444 (interactive "sGopher or Gemini URL: ")
1445 (let* ((cleaned-host-or-url (string-trim host-or-url))
1446 (address (elpher-address-from-url cleaned-host-or-url))
1447 (page (elpher-make-page cleaned-host-or-url address)))
1448 (switch-to-buffer "*elpher*")
1449 (elpher-visit-page page)
1452 (defun elpher-go-current ()
1453 "Go to a particular site read from the minibuffer, initialized with the current URL."
1455 (let ((address (elpher-page-address elpher-current-page)))
1456 (if (elpher-address-special-p address)
1457 (error "Command invalid for this page")
1458 (let ((url (read-string "Gopher or Gemini URL: " (elpher-address-to-url address))))
1459 (elpher-visit-page (elpher-make-page url (elpher-address-from-url url)))))))
1461 (defun elpher-redraw ()
1462 "Redraw current page."
1464 (elpher-visit-page elpher-current-page))
1466 (defun elpher-reload ()
1467 "Reload current page."
1469 (elpher-reload-current-page))
1471 (defun elpher-toggle-tls ()
1472 "Toggle TLS encryption mode for gopher."
1474 (setq elpher-use-tls (not elpher-use-tls))
1476 (if (gnutls-available-p)
1477 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
1478 (setq elpher-use-tls nil)
1479 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
1480 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
1482 (defun elpher-view-raw ()
1483 "View raw server response for current page."
1485 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
1486 (error "This page was not generated by a server")
1487 (elpher-visit-page elpher-current-page
1488 #'elpher-render-raw)))
1490 (defun elpher-back ()
1491 "Go to previous site."
1493 (elpher-visit-previous-page))
1495 (defun elpher-back-to-start ()
1496 "Go all the way back to the start page."
1498 (setq elpher-current-page nil)
1499 (setq elpher-history nil)
1500 (let ((start-page (elpher-make-page "Elpher Start Page"
1501 (elpher-make-special-address 'start))))
1502 (elpher-visit-page start-page)))
1504 (defun elpher-download ()
1505 "Download the link at point."
1507 (let ((button (button-at (point))))
1509 (let ((page (button-get button 'elpher-page)))
1510 (if (elpher-address-special-p (elpher-page-address page))
1511 (error "Cannot download %s"
1512 (elpher-page-display-string page))
1513 (elpher-visit-page (button-get button 'elpher-page)
1514 #'elpher-render-download)))
1515 (error "No link selected"))))
1517 (defun elpher-download-current ()
1518 "Download the current page."
1520 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
1521 (error "Cannot download %s"
1522 (elpher-page-display-string elpher-current-page))
1523 (elpher-visit-page (elpher-make-page
1524 (elpher-page-display-string elpher-current-page)
1525 (elpher-page-address elpher-current-page))
1526 #'elpher-render-download
1529 (defun elpher-build-link-map ()
1530 "Build alist mapping link names to destination pages in current buffer."
1531 (let ((link-map nil)
1532 (b (next-button (point-min) t)))
1534 (push (cons (button-label b) b) link-map)
1535 (setq b (next-button (button-start b))))
1538 (defun elpher-jump ()
1539 "Select a directory entry by name. Similar to the info browser (m)enu command."
1541 (let* ((link-map (elpher-build-link-map)))
1543 (let ((key (let ((completion-ignore-case t))
1544 (completing-read "Directory item/link: "
1546 (if (and key (> (length key) 0))
1547 (let ((b (cdr (assoc key link-map))))
1548 (goto-char (button-start b))
1549 (button-activate b)))))))
1551 (defun elpher-root-dir ()
1552 "Visit root of current server."
1554 (let ((address (elpher-page-address elpher-current-page)))
1555 (if (not (elpher-address-special-p address))
1556 (if (or (member (url-filename address) '("/" ""))
1557 (and (elpher-address-gopher-p address)
1558 (= (length (elpher-gopher-address-selector address)) 0)))
1559 (error "Already at root directory of current server")
1560 (let ((address-copy (elpher-address-from-url
1561 (elpher-address-to-url address))))
1562 (setf (url-filename address-copy) "")
1563 (elpher-go (elpher-address-to-url address-copy))))
1564 (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
1566 (defun elpher-bookmarks-current-p ()
1567 "Return non-nil if current page is a bookmarks page."
1568 (equal (elpher-address-type (elpher-page-address elpher-current-page))
1569 '(special bookmarks)))
1571 (defun elpher-reload-bookmarks ()
1572 "Reload bookmarks if current page is a bookmarks page."
1573 (if (elpher-bookmarks-current-p)
1574 (elpher-reload-current-page)))
1576 (defun elpher-bookmark-current ()
1577 "Bookmark the current page."
1579 (let ((address (elpher-page-address elpher-current-page))
1580 (display-string (elpher-page-display-string elpher-current-page)))
1581 (if (not (elpher-address-special-p address))
1582 (let ((bookmark-display-string (read-string "Bookmark display string: "
1584 (elpher-add-address-bookmark address bookmark-display-string)
1585 (message "Bookmark added."))
1586 (error "Cannot bookmark %s" display-string))))
1588 (defun elpher-bookmark-link ()
1589 "Bookmark the link at point."
1591 (let ((button (button-at (point))))
1593 (let* ((page (button-get button 'elpher-page))
1594 (address (elpher-page-address page))
1595 (display-string (elpher-page-display-string page)))
1596 (if (not (elpher-address-special-p address))
1597 (let ((bookmark-display-string (read-string "Bookmark display string: "
1599 (elpher-add-address-bookmark address bookmark-display-string)
1600 (elpher-reload-bookmarks)
1601 (message "Bookmark added."))
1602 (error "Cannot bookmark %s" display-string)))
1603 (error "No link selected"))))
1605 (defun elpher-unbookmark-current ()
1606 "Remove bookmark for the current page."
1608 (let ((address (elpher-page-address elpher-current-page)))
1609 (when (and (not (elpher-address-special-p address))
1610 (y-or-n-p "Really remove bookmark for the current page? "))
1611 (elpher-remove-address-bookmark address)
1612 (message "Bookmark removed."))))
1614 (defun elpher-unbookmark-link ()
1615 "Remove bookmark for the link at point."
1617 (let ((button (button-at (point))))
1619 (when (y-or-n-p "Really remove bookmark for this link? ")
1620 (let ((page (button-get button 'elpher-page)))
1621 (elpher-remove-address-bookmark (elpher-page-address page))
1622 (elpher-reload-bookmarks)
1623 (message "Bookmark removed.")))
1624 (error "No link selected"))))
1626 (defun elpher-bookmarks ()
1627 "Visit bookmarks page."
1629 (switch-to-buffer "*elpher*")
1631 (elpher-make-page "Bookmarks Page" (elpher-make-special-address 'bookmarks))))
1633 (defun elpher-info-page (page)
1634 "Display information on PAGE."
1635 (let ((display-string (elpher-page-display-string page))
1636 (address (elpher-page-address page)))
1637 (if (elpher-address-special-p address)
1638 (message "Special page: %s" display-string)
1639 (message "%s" (elpher-address-to-url address)))))
1641 (defun elpher-info-link ()
1642 "Display information on page corresponding to link at point."
1644 (let ((button (button-at (point))))
1646 (elpher-info-page (button-get button 'elpher-page))
1647 (error "No item selected"))))
1649 (defun elpher-info-current ()
1650 "Display information on current page."
1652 (elpher-info-page elpher-current-page))
1654 (defun elpher-copy-page-url (page)
1655 "Copy URL representation of address of PAGE to `kill-ring'."
1656 (let ((address (elpher-page-address page)))
1657 (if (elpher-address-special-p address)
1658 (error (format "Cannot represent %s as URL" (elpher-page-display-string page)))
1659 (let ((url (elpher-address-to-url address)))
1660 (message "Copied \"%s\" to kill-ring/clipboard." url)
1663 (defun elpher-copy-link-url ()
1664 "Copy URL of item at point to `kill-ring'."
1666 (let ((button (button-at (point))))
1668 (elpher-copy-page-url (button-get button 'elpher-page))
1669 (error "No item selected"))))
1671 (defun elpher-copy-current-url ()
1672 "Copy URL of current page to `kill-ring'."
1674 (elpher-copy-page-url elpher-current-page))
1676 (defun elpher-set-gopher-coding-system ()
1677 "Specify an explicit character coding system for gopher selectors."
1679 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
1680 (setq elpher-user-coding-system system)
1682 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
1683 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
1689 (defvar elpher-mode-map
1690 (let ((map (make-sparse-keymap)))
1691 (define-key map (kbd "TAB") 'elpher-next-link)
1692 (define-key map (kbd "<backtab>") 'elpher-prev-link)
1693 (define-key map (kbd "C-M-i") 'elpher-prev-link)
1694 (define-key map (kbd "u") 'elpher-back)
1695 (define-key map (kbd "U") 'elpher-back-to-start)
1696 (define-key map [mouse-3] 'elpher-back)
1697 (define-key map (kbd "O") 'elpher-root-dir)
1698 (define-key map (kbd "g") 'elpher-go)
1699 (define-key map (kbd "o") 'elpher-go-current)
1700 (define-key map (kbd "r") 'elpher-redraw)
1701 (define-key map (kbd "R") 'elpher-reload)
1702 (define-key map (kbd "T") 'elpher-toggle-tls)
1703 (define-key map (kbd ".") 'elpher-view-raw)
1704 (define-key map (kbd "d") 'elpher-download)
1705 (define-key map (kbd "D") 'elpher-download-current)
1706 (define-key map (kbd "m") 'elpher-jump)
1707 (define-key map (kbd "i") 'elpher-info-link)
1708 (define-key map (kbd "I") 'elpher-info-current)
1709 (define-key map (kbd "c") 'elpher-copy-link-url)
1710 (define-key map (kbd "C") 'elpher-copy-current-url)
1711 (define-key map (kbd "a") 'elpher-bookmark-link)
1712 (define-key map (kbd "A") 'elpher-bookmark-current)
1713 (define-key map (kbd "x") 'elpher-unbookmark-link)
1714 (define-key map (kbd "X") 'elpher-unbookmark-current)
1715 (define-key map (kbd "B") 'elpher-bookmarks)
1716 (define-key map (kbd "S") 'elpher-set-gopher-coding-system)
1717 (when (fboundp 'evil-define-key*)
1718 (evil-define-key* 'motion map
1719 (kbd "TAB") 'elpher-next-link
1720 (kbd "C-") 'elpher-follow-current-link
1721 (kbd "C-t") 'elpher-back
1722 (kbd "u") 'elpher-back
1723 (kbd "U") 'elpher-back-to-start
1724 [mouse-3] 'elpher-back
1725 (kbd "g") 'elpher-go
1726 (kbd "o") 'elpher-go-current
1727 (kbd "r") 'elpher-redraw
1728 (kbd "R") 'elpher-reload
1729 (kbd "T") 'elpher-toggle-tls
1730 (kbd ".") 'elpher-view-raw
1731 (kbd "d") 'elpher-download
1732 (kbd "D") 'elpher-download-current
1733 (kbd "m") 'elpher-jump
1734 (kbd "i") 'elpher-info-link
1735 (kbd "I") 'elpher-info-current
1736 (kbd "c") 'elpher-copy-link-url
1737 (kbd "C") 'elpher-copy-current-url
1738 (kbd "a") 'elpher-bookmark-link
1739 (kbd "A") 'elpher-bookmark-current
1740 (kbd "x") 'elpher-unbookmark-link
1741 (kbd "X") 'elpher-unbookmark-current
1742 (kbd "B") 'elpher-bookmarks
1743 (kbd "S") 'elpher-set-gopher-coding-system))
1745 "Keymap for gopher client.")
1747 (define-derived-mode elpher-mode special-mode "elpher"
1748 "Major mode for elpher, an elisp gopher client.
1750 This mode is automatically enabled by the interactive
1751 functions which initialize the gopher client, namely
1752 `elpher', `elpher-go' and `elpher-bookmarks'.")
1754 (when (fboundp 'evil-set-initial-state)
1755 (evil-set-initial-state 'elpher-mode 'motion))
1758 ;;; Main start procedure
1763 "Start elpher with default landing page."
1765 (if (get-buffer "*elpher*")
1766 (switch-to-buffer "*elpher*")
1767 (switch-to-buffer "*elpher*")
1768 (setq elpher-current-page nil)
1769 (setq elpher-history nil)
1770 (let ((start-page (elpher-make-page "Elpher Start Page"
1771 (elpher-make-special-address 'start))))
1772 (elpher-visit-page start-page)))
1773 "Started Elpher.") ; Otherwise (elpher) evaluates to start page string.
1775 ;;; elpher.el ends here