1 ;;; elpher.el --- A friendly gopher client -*- lexical-binding:t -*-
3 ;; Copyright (C) 2019 Tim Vaughan
5 ;; Author: Tim Vaughan <timv@ughan.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 client
30 ;; 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 ;; - connections using TLS encryption,
40 ;; - the fledgling Gemini protocol.
42 ;; To launch Elpher, simply use 'M-x elpher'. This will open a start
43 ;; page containing information on key bindings and suggested starting
44 ;; points for your gopher exploration.
46 ;; Full instructions can be found in the Elpher info manual.
48 ;; Elpher is under active development. Any suggestions for
49 ;; improvements are welcome, and can be made on the official
50 ;; project page, gopher://thelambdalab.xyz/1/projects/elpher/.
70 (defconst elpher-version "2.5.1"
71 "Current version of elpher.")
73 (defconst elpher-margin-width 6
74 "Width of left-hand margin used when rendering indicies.")
76 (defconst elpher-type-map
77 '(((gopher ?0) elpher-get-gopher-page elpher-render-text "txt" elpher-text)
78 ((gopher ?1) elpher-get-gopher-page elpher-render-index "/" elpher-index)
79 ((gopher ?4) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
80 ((gopher ?5) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
81 ((gopher ?7) elpher-get-gopher-query-page elpher-render-index "?" elpher-search)
82 ((gopher ?9) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
83 ((gopher ?g) elpher-get-gopher-page elpher-render-image "img" elpher-image)
84 ((gopher ?p) elpher-get-gopher-page elpher-render-image "img" elpher-image)
85 ((gopher ?I) elpher-get-gopher-page elpher-render-image "img" elpher-image)
86 ((gopher ?d) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
87 ((gopher ?P) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
88 ((gopher ?s) elpher-get-gopher-page elpher-render-download "snd" elpher-binary)
89 ((gopher ?h) elpher-get-gopher-page elpher-render-html "htm" elpher-html)
90 (gemini elpher-get-gemini-page elpher-render-gemini "gem" elpher-gemini)
91 (telnet elpher-get-telnet-page nil "tel" elpher-telnet)
92 (other-url elpher-get-other-url-page nil "url" elpher-other-url)
93 ((special bookmarks) elpher-get-bookmarks-page nil "/" elpher-index)
94 ((special start) elpher-get-start-page nil))
95 "Association list from types to getters, renderers, margin codes and index faces.")
98 ;;; Customization group
103 :group 'applications)
105 ;; Face customizations
107 (defface elpher-index
108 '((t :inherit font-lock-keyword-face))
109 "Face used for directory type directory records.")
113 "Face used for text type directory records.")
116 '((t :inherit default))
117 "Face used for info type directory records.")
119 (defface elpher-image
120 '((t :inherit font-lock-string-face))
121 "Face used for image type directory records.")
123 (defface elpher-search
124 '((t :inherit warning))
125 "Face used for search type directory records.")
128 '((t :inherit font-lock-comment-face))
129 "Face used for html type directory records.")
131 (defface elpher-gemini
132 '((t :inherit font-lock-regexp-grouping-backslash))
133 "Face used for html type directory records.")
135 (defface elpher-other-url
136 '((t :inherit font-lock-comment-face))
137 "Face used for other URL type links records.")
139 (defface elpher-telnet
140 '((t :inherit font-lock-function-name-face))
141 "Face used for telnet type directory records.")
143 (defface elpher-binary
144 '((t :inherit font-lock-doc-face))
145 "Face used for binary type directory records.")
147 (defface elpher-unknown
148 '((t :inherit error))
149 "Face used for directory records with unknown/unsupported types.")
151 (defface elpher-margin-key
153 "Face used for directory margin key.")
155 (defface elpher-margin-brackets
156 '((t :inherit shadow))
157 "Face used for brackets around directory margin key.")
159 ;; Other customizations
161 (defcustom elpher-open-urls-with-eww nil
162 "If non-nil, open URL selectors using eww.
163 Otherwise, use the system browser via the BROWSE-URL function."
166 (defcustom elpher-use-header t
167 "If non-nil, display current page information in buffer header."
170 (defcustom elpher-auto-disengage-TLS nil
171 "If non-nil, automatically disengage TLS following an unsuccessful connection.
172 While enabling this may seem convenient, it is also potentially dangerous as it
173 allows switching from an encrypted channel back to plain text without user input."
176 (defcustom elpher-connection-timeout 5
177 "Specifies the number of seconds to wait for a network connection to time out."
180 (defcustom elpher-strip-ansi-from-text t
181 "If non-nil, strip ANSI escape sequences from gopher menus and text/gemini files.
182 This is occasionally desirable, as these sequences are not understood natively by
183 Emacs, and tend to result in a garbled display."
191 ;; An elpher "address" object is either a url object or a symbol.
192 ;; Symbol addresses are "special", corresponding to pages generated
193 ;; dynamically for and by elpher. All others represent pages which
194 ;; rely on content retrieved over the network.
196 (defun elpher-address-from-url (url-string)
197 "Create a ADDRESS object corresponding to the given URL-STRING."
198 (let ((data (match-data))) ; Prevent parsing clobbering match data
200 (let ((url (url-generic-parse-url url-string)))
201 (unless (and (not (url-fullness url)) (url-type url))
202 (setf (url-fullness url) t)
203 (setf (url-filename url)
204 (url-unhex-string (url-filename url)))
205 (unless (url-type url)
206 (setf (url-type url) "gopher"))
207 (when (or (equal "gopher" (url-type url))
208 (equal "gophers" (url-type url)))
210 (unless (url-host url)
211 (setf (url-host url) (url-filename url))
212 (setf (url-filename url) ""))
213 (when (or (equal (url-filename url) "")
214 (equal (url-filename url) "/"))
215 (setf (url-filename url) "/1")))
216 (when (equal "gemini" (url-type url))
218 (if (equal (url-filename url) "")
219 (setf (url-filename url) "/"))))
221 (set-match-data data))))
223 (defun elpher-make-gopher-address (type selector host port &optional tls)
224 "Create an ADDRESS object using gopher directory record attributes.
225 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
226 If the optional attribute TLS is non-nil, the address will be marked as
227 requiring gopher-over-TLS."
229 ((and (equal type ?h)
230 (string-prefix-p "URL:" selector))
231 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
233 (elpher-address-from-url
236 ":" (number-to-string port))))
238 (elpher-address-from-url
239 (concat "gopher" (if tls "s" "")
241 ":" (number-to-string port)
245 (defun elpher-make-special-address (type)
246 "Create an ADDRESS object corresponding to the given special address symbol TYPE."
249 (defun elpher-address-to-url (address)
250 "Get string representation of ADDRESS, or nil if ADDRESS is special."
251 (if (not (elpher-address-special-p address))
252 (url-encode-url (url-recreate-url address))
255 (defun elpher-address-type (address)
256 "Retrieve type of ADDRESS object.
257 This is used to determine how to retrieve and render the document the
258 address refers to, via the table `elpher-type-map'."
259 (if (symbolp address)
260 (list 'special address)
261 (let ((protocol (url-type address)))
262 (cond ((or (equal protocol "gopher")
263 (equal protocol "gophers"))
265 (if (member (url-filename address) '("" "/"))
267 (string-to-char (substring (url-filename address) 1)))))
268 ((equal protocol "gemini")
270 ((equal protocol "telnet")
274 (defun elpher-address-protocol (address)
275 "Retrieve the transport protocol for ADDRESS. This is nil for special addresses."
276 (if (symbolp address)
280 (defun elpher-address-filename (address)
281 "Retrieve the filename component of ADDRESS.
282 For gopher addresses this is a combination of the selector type and selector."
283 (if (symbolp address)
285 (url-filename address)))
287 (defun elpher-address-host (address)
288 "Retrieve host from ADDRESS object."
291 (defun elpher-address-port (address)
292 "Retrieve port from ADDRESS object.
293 If no address is defined, returns 0. (This is for compatibility with the URL library.)"
294 (if (symbolp address)
298 (defun elpher-address-special-p (address)
299 "Return non-nil if ADDRESS object is special (e.g. start page, bookmarks page)."
302 (defun elpher-address-gopher-p (address)
303 "Return non-nill if ADDRESS object is a gopher address."
304 (and (not (elpher-address-special-p address))
305 (member (elpher-address-protocol address) '("gopher gophers"))))
307 (defun elpher-gopher-address-selector (address)
308 "Retrieve gopher selector from ADDRESS object."
309 (if (member (url-filename address) '("" "/"))
311 (substring (url-filename address) 2)))
316 (defvar elpher-content-cache (make-hash-table :test 'equal))
317 (defvar elpher-pos-cache (make-hash-table :test 'equal))
319 (defun elpher-get-cached-content (address)
320 "Retrieve the cached content for ADDRESS, or nil if none exists."
321 (gethash address elpher-content-cache))
323 (defun elpher-cache-content (address content)
324 "Set the content cache for ADDRESS to CONTENT."
325 (puthash address content elpher-content-cache))
327 (defun elpher-get-cached-pos (address)
328 "Retrieve the cached cursor position for ADDRESS, or nil if none exists."
329 (gethash address elpher-pos-cache))
331 (defun elpher-cache-pos (address pos)
332 "Set the cursor position cache for ADDRESS to POS."
333 (puthash address pos elpher-pos-cache))
338 (defun elpher-make-page (display-string address)
339 (list display-string address))
341 (defun elpher-page-display-string (page)
344 (defun elpher-page-address (page)
347 (defvar elpher-current-page nil)
348 (defvar elpher-history nil)
350 (defun elpher-visit-page (page &optional renderer no-history)
351 "Visit PAGE using its own renderer or RENDERER, if non-nil.
352 Additionally, push PAGE onto the stack of previously-visited pages,
353 unless NO-HISTORY is non-nil."
355 (elpher-process-cleanup)
356 (unless (or no-history
357 (equal (elpher-page-address elpher-current-page)
358 (elpher-page-address page)))
359 (push elpher-current-page elpher-history))
360 (setq elpher-current-page page)
361 (let* ((address (elpher-page-address page))
362 (type (elpher-address-type address))
363 (type-record (cdr (assoc type elpher-type-map))))
365 (funcall (car type-record)
369 (elpher-visit-previous-page)
371 (`(gopher ,type-char)
372 (error "Unsupported gopher selector type '%c' for '%s'"
373 type-char (elpher-address-to-url address)))
375 (error "Unsupported address type '%S' for '%s'"
376 other (elpher-address-to-url address)))))))
378 (defun elpher-visit-previous-page ()
379 "Visit the previous page in the history."
380 (let ((previous-page (pop elpher-history)))
382 (elpher-visit-page previous-page nil t)
383 (error "No previous page."))))
385 (defun elpher-reload-current-page ()
386 "Reload the current page, discarding any existing cached content."
387 (elpher-cache-content (elpher-page-address elpher-current-page) nil)
388 (elpher-visit-page elpher-current-page))
390 (defun elpher-save-pos ()
391 "Save the current position of point to the current page."
392 (when elpher-current-page
393 (elpher-cache-pos (elpher-page-address elpher-current-page) (point))))
395 (defun elpher-restore-pos ()
396 "Restore the position of point to that cached in the current page."
397 (let ((pos (elpher-get-cached-pos (elpher-page-address elpher-current-page))))
400 (goto-char (point-min)))))
403 ;;; Buffer preparation
406 (defun elpher-update-header ()
407 "If `elpher-use-header' is true, display current page info in window header."
408 (if elpher-use-header
409 (let* ((display-string (elpher-page-display-string elpher-current-page))
410 (address (elpher-page-address elpher-current-page))
411 (tls-string (if (and (not (elpher-address-special-p address))
412 (member (elpher-address-protocol address)
413 '("gophers" "gemini")))
416 (header (concat display-string
417 (propertize tls-string 'face 'bold))))
418 (setq header-line-format header))))
420 (defmacro elpher-with-clean-buffer (&rest args)
421 "Evaluate ARGS with a clean *elpher* buffer as current."
422 (list 'with-current-buffer "*elpher*"
424 (append (list 'let '((inhibit-read-only t))
426 '(elpher-update-header))
433 (defvar elpher-user-coding-system nil
434 "User-specified coding system to use for decoding text responses.")
436 (defun elpher-decode (string)
437 "Decode STRING using autodetected or user-specified coding system."
438 (decode-coding-string string
439 (if elpher-user-coding-system
440 elpher-user-coding-system
441 (detect-coding-string string t))))
443 (defun elpher-preprocess-text-response (string)
444 "Preprocess text selector response contained in STRING.
445 This involes decoding the character representation, and clearing
446 away CRs and any terminating period."
447 (elpher-decode (replace-regexp-in-string "\n\.\n$" "\n"
448 (replace-regexp-in-string "\r" "" string))))
451 ;;; Network error reporting
454 (defun elpher-network-error (address error)
455 "Display ERROR message following unsuccessful negotiation with ADDRESS.
456 ERROR can be either an error object or a string."
457 (elpher-with-clean-buffer
458 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
459 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
460 (if (stringp error) error (error-message-string error)) "\n"
461 (propertize "\n----------------\n\n" 'face 'error)
462 "Press 'u' to return to the previous page.")))
465 ;;; Gopher selector retrieval
468 (defvar elpher-network-timer nil
469 "Timer used for network connections.")
471 (defun elpher-process-cleanup ()
472 "Immediately shut down any extant elpher process and timers."
473 (let ((p (get-process "elpher-process")))
474 (if p (delete-process p)))
475 (if (timerp elpher-network-timer)
476 (cancel-timer elpher-network-timer)))
478 (defvar elpher-use-tls nil
479 "If non-nil, use TLS to communicate with gopher servers.")
481 (defun elpher-get-selector (address renderer &optional force-ipv4)
482 "Retrieve selector specified by ADDRESS, then render it using RENDERER.
483 If FORCE-IPV4 is non-nil, explicitly look up and use IPv4 address corresponding
485 (when (equal (elpher-address-protocol address) "gophers")
486 (if (gnutls-available-p)
487 (when (not elpher-use-tls)
488 (setq elpher-use-tls t)
489 (message "Engaging TLS gopher mode."))
490 (error "Cannot retrieve TLS gopher selector: GnuTLS not available")))
491 (unless (< (elpher-address-port address) 65536)
492 (error "Cannot retrieve gopher selector: port number > 65536"))
494 (let* ((kill-buffer-query-functions nil)
495 (port (elpher-address-port address))
496 (host (elpher-address-host address))
498 (proc (open-network-stream "elpher-process"
500 (if force-ipv4 (dns-query host) host)
501 (if (> port 0) port 70)
502 :type (if elpher-use-tls 'tls 'plain)
504 (timer (run-at-time elpher-connection-timeout
507 (pcase (process-status proc)
509 (if (and (not (equal (elpher-address-protocol address)
512 (or elpher-auto-disengage-TLS
513 (yes-or-no-p "Could not establish encrypted connection. Disable TLS mode?")))
515 (message "Disabling TLS mode.")
516 (setq elpher-use-tls nil)
517 (elpher-get-selector address renderer))
518 (elpher-network-error address "Could not establish encrypted connection")))
520 (elpher-process-cleanup)
522 (message "Connection timed out. Retrying with IPv4 address.")
523 (elpher-get-selector address renderer t))))))))
524 (setq elpher-network-timer timer)
525 (set-process-coding-system proc 'binary)
526 (set-process-filter proc
527 (lambda (_proc string)
529 (setq selector-string
530 (concat selector-string string))))
531 (set-process-sentinel proc
532 (lambda (_proc event)
533 (condition-case the-error
535 ((string-prefix-p "deleted" event))
536 ((string-prefix-p "open" event)
537 (let ((inhibit-eol-conversion t))
540 (concat (elpher-gopher-address-selector address)
544 (funcall renderer selector-string)
545 (elpher-restore-pos)))
547 (elpher-network-error address the-error))))))
549 (error "Error initiating connection to server"))))
551 (defun elpher-get-gopher-page (renderer)
552 "Getter function for gopher pages.
553 The RENDERER procedure is used to display the contents of the page
554 once they are retrieved from the gopher server."
555 (let* ((address (elpher-page-address elpher-current-page))
556 (content (elpher-get-cached-content address)))
557 (if (and content (funcall renderer nil))
558 (elpher-with-clean-buffer
560 (elpher-restore-pos))
561 (elpher-with-clean-buffer
562 (insert "LOADING... (use 'u' to cancel)"))
563 (condition-case the-error
564 (elpher-get-selector address renderer)
566 (elpher-network-error address the-error))))))
570 (defun elpher-insert-index (string)
571 "Insert the index corresponding to STRING into the current buffer."
572 ;; Should be able to split directly on CRLF, but some non-conformant
573 ;; LF-only servers sadly exist, hence the following.
574 (let ((str-processed (elpher-preprocess-text-response string)))
575 (dolist (line (split-string str-processed "\n"))
577 (unless (= (length line) 0)
578 (let* ((type (elt line 0))
579 (fields (split-string (substring line 1) "\t"))
580 (display-string (elt fields 0))
581 (selector (elt fields 1))
582 (host (elt fields 2))
583 (port (if (elt fields 3)
584 (string-to-number (elt fields 3))
586 (address (elpher-make-gopher-address type selector host port)))
587 (elpher-insert-index-record display-string address)))))))
589 (defun elpher-insert-margin (&optional type-name)
590 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
593 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
595 (propertize "[" 'face 'elpher-margin-brackets)
596 (propertize type-name 'face 'elpher-margin-key)
597 (propertize "]" 'face 'elpher-margin-brackets))))
599 (insert (make-string elpher-margin-width ?\s))))
601 (defun elpher-page-button-help (page)
602 "Return a string containing the help text for a button corresponding to PAGE."
603 (let ((address (elpher-page-address page)))
604 (format "mouse-1, RET: open '%s'" (if (elpher-address-special-p address)
606 (elpher-address-to-url address)))))
608 (defun elpher-insert-index-record (display-string &optional address)
609 "Function to insert an index record into the current buffer.
610 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
611 If ADDRESS is not supplied or nil the record is rendered as an
613 (let* ((type (if address (elpher-address-type address) nil))
614 (type-map-entry (cdr (assoc type elpher-type-map))))
616 (let* ((margin-code (elt type-map-entry 2))
617 (face (elt type-map-entry 3))
618 (page (elpher-make-page display-string address)))
619 (elpher-insert-margin margin-code)
620 (insert-text-button display-string
623 'action #'elpher-click-link
625 'help-echo (elpher-page-button-help page)))
627 ((or '(gopher ?i) 'nil) ;; Information
628 (elpher-insert-margin)
629 (let ((propertized-display-string
630 (propertize display-string 'face 'elpher-info)))
631 (insert (elpher-process-text-for-display propertized-display-string))))
632 (`(gopher ,selector-type) ;; Unknown
633 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
634 (insert (propertize display-string
635 'face 'elpher-unknown)))))
638 (defun elpher-click-link (button)
639 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
640 (let ((page (button-get button 'elpher-page)))
641 (elpher-visit-page page)))
643 (defun elpher-render-index (data &optional _mime-type-string)
644 "Render DATA as an index. MIME-TYPE-STRING is unused."
645 (elpher-with-clean-buffer
648 (elpher-insert-index data)
649 (elpher-cache-content (elpher-page-address elpher-current-page)
654 (defconst elpher-url-regex
655 "\\([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\-_~?/@|#]\\)?\\)?"
656 "Regexp used to locate and buttinofy URLs in text files loaded by elpher.")
658 (defun elpher-buttonify-urls (string)
659 "Turn substrings which look like urls in STRING into clickable buttons."
662 (goto-char (point-min))
663 (while (re-search-forward elpher-url-regex nil t)
664 (let ((page (elpher-make-page (substring-no-properties (match-string 0))
665 (elpher-address-from-url (match-string 0)))))
666 (make-text-button (match-beginning 0)
669 'action #'elpher-click-link
671 'help-echo (elpher-page-button-help page)
675 (defconst elpher-ansi-regex "\x1b\\[[^m]*m"
676 "Wildly incomplete regexp used to strip out some troublesome ANSI escape sequences.")
678 (defun elpher-strip-ansi (string)
679 "Strip ANSI escape codes from STRING."
682 (goto-char (point-min))
683 (while (re-search-forward elpher-ansi-regex nil t)
684 (delete-region (match-beginning 0) (match-end 0)))
688 (defun elpher-process-text-for-display (string)
689 "Perform any desired processing of text prior to display.
690 Currently includes buttonifying URLs and optionally stripping ANSI escape codes."
691 (elpher-buttonify-urls (if elpher-strip-ansi-from-text
692 (elpher-strip-ansi string)
695 (defun elpher-render-text (data &optional _mime-type-string)
696 "Render DATA as text. MIME-TYPE-STRING is unused."
697 (elpher-with-clean-buffer
700 (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
701 (elpher-cache-content
702 (elpher-page-address elpher-current-page)
707 (defun elpher-render-image (data &optional _mime-type-string)
708 "Display DATA as image. MIME-TYPE-STRING is unused."
711 (if (display-images-p)
713 (let ((image (create-image
716 (elpher-with-clean-buffer
718 (elpher-restore-pos))))
719 (elpher-render-download data))))
721 ;; Search retrieval and rendering
723 (defun elpher-get-gopher-query-page (renderer)
724 "Getter for gopher addresses requiring input.
725 The response is rendered using the rendering function RENDERER."
726 (let* ((address (elpher-page-address elpher-current-page))
727 (content (elpher-get-cached-content address))
729 (if (and content (funcall renderer nil))
730 (elpher-with-clean-buffer
733 (message "Displaying cached search results. Reload to perform a new search."))
735 (let* ((query-string (read-string "Query: "))
736 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
737 (search-address (elpher-make-gopher-address ?1
739 (elpher-address-host address)
740 (elpher-address-port address)
741 (equal (elpher-address-type address) "gophers"))))
744 (elpher-with-clean-buffer
745 (insert "LOADING RESULTS... (use 'u' to cancel)"))
746 (elpher-get-selector search-address renderer))
748 (elpher-visit-previous-page))))))
750 ;; Raw server response rendering
752 (defun elpher-render-raw (data &optional mime-type-string)
753 "Display raw DATA in buffer. MIME-TYPE-STRING is also displayed if provided."
756 (elpher-with-clean-buffer
757 (when mime-type-string
758 (insert "MIME type specified by server: '" mime-type-string "'\n"))
760 (goto-char (point-min)))
761 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
763 ;; File save "rendering"
765 (defun elpher-render-download (data &optional _mime-type-string)
766 "Save DATA to file. MIME-TYPE-STRING is unused."
769 (let* ((address (elpher-page-address elpher-current-page))
770 (selector (elpher-gopher-address-selector address)))
771 (elpher-visit-previous-page) ; Do first in case of non-local exits.
772 (let* ((filename-proposal (file-name-nondirectory selector))
773 (filename (read-file-name "Download complete. Save file as: "
775 (if (> (length filename-proposal) 0)
778 (let ((coding-system-for-write 'binary))
779 (with-temp-file filename
781 (message (format "Saved to file %s." filename))))))
785 (defun elpher-render-html (data &optional _mime-type-string)
786 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
787 (elpher-with-clean-buffer
790 (let ((dom (with-temp-buffer
792 (libxml-parse-html-region (point-min) (point-max)))))
793 (shr-insert-document dom)))))
795 ;; Gemini page retrieval
797 (defvar elpher-gemini-redirect-chain)
799 (defun elpher-get-gemini-response (address renderer &optional force-ipv4)
800 "Retrieve gemini ADDRESS, then render using RENDERER.
801 If FORCE-IPV4 is non-nil, explicitly look up and use IPv4 address corresponding
803 (if (not (gnutls-available-p))
804 (error "Cannot establish gemini connection: GnuTLS not available")
805 (unless (< (elpher-address-port address) 65536)
806 (error "Cannot establish gemini connection: port number > 65536"))
808 (let* ((kill-buffer-query-functions nil)
809 (port (elpher-address-port address))
810 (host (elpher-address-host address))
812 (proc (open-network-stream "elpher-process"
814 (if force-ipv4 (dns-query host) host)
815 (if (> port 0) port 1965)
818 (timer (run-at-time elpher-connection-timeout nil
820 (elpher-process-cleanup)
822 ; Try again with IPv4
823 (message "Connection timed out. Retrying with IPv4.")
824 (elpher-get-gemini-response address renderer t))))))
825 (setq elpher-network-timer timer)
826 (set-process-coding-system proc 'binary)
827 (set-process-filter proc
828 (lambda (_proc string)
830 (setq response-string
831 (concat response-string string))))
832 (set-process-sentinel proc
834 (condition-case the-error
836 ((string-prefix-p "open" event) ; request URL
837 (let ((inhibit-eol-conversion t))
840 (concat (elpher-address-to-url address)
842 ((string-prefix-p "deleted" event)) ; do nothing
843 ((and (string-empty-p response-string)
845 ; Try again with IPv4
846 (message "Connection failed. Retrying with IPv4.")
848 (elpher-get-gemini-response address renderer t))
850 (funcall #'elpher-process-gemini-response
853 (elpher-restore-pos)))
855 (elpher-network-error address the-error))))))
857 (error "Error initiating connection to server")))))
859 (defun elpher-parse-gemini-response (response)
860 "Parse the RESPONSE string and return a list of components.
861 The list is of the form (code meta body). A response of nil implies
862 that the response was malformed."
863 (let ((header-end-idx (string-match "\r\n" response)))
865 (let ((header (string-trim (substring response 0 header-end-idx)))
866 (body (substring response (+ header-end-idx 2))))
867 (if (>= (length header) 2)
868 (let ((code (substring header 0 2))
869 (meta (string-trim (substring header 2))))
870 (list code meta body))
871 (error "Malformed response: No response status found in header %s" header)))
872 (error "Malformed response: No CRLF-delimited header found"))))
874 (defun elpher-process-gemini-response (response-string renderer)
875 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
876 (let ((response-components (elpher-parse-gemini-response response-string)))
877 (let ((response-code (elt response-components 0))
878 (response-meta (elt response-components 1))
879 (response-body (elt response-components 2)))
880 (pcase (elt response-code 0)
882 (elpher-with-clean-buffer
883 (insert "Gemini server is requesting input."))
884 (let* ((query-string (read-string (concat response-meta ": ")))
885 (url (elpher-address-to-url (elpher-page-address elpher-current-page)))
886 (query-address (elpher-address-from-url (concat url "?" query-string))))
887 (elpher-get-gemini-response query-address renderer)))
888 (?2 ; Normal response
889 (funcall renderer response-body response-meta))
891 (message "Following redirect to %s" response-meta)
892 (if (>= (length elpher-gemini-redirect-chain) 5)
893 (error "More than 5 consecutive redirects followed"))
894 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
895 (if (member redirect-address elpher-gemini-redirect-chain)
896 (error "Redirect loop detected"))
897 (if (not (string= (elpher-address-protocol redirect-address)
899 (error "Server tried to automatically redirect to non-gemini URL: %s"
901 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
902 (elpher-get-gemini-response redirect-address renderer)))
903 (?4 ; Temporary failure
904 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
905 response-code response-meta))
906 (?5 ; Permanent failure
907 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
908 response-code response-meta))
909 (?6 ; Client certificate required
910 (error "Gemini server requires client certificate (unsupported at this time)"))
912 (error "Gemini server response unknown: %s %s"
913 response-code response-meta))))))
915 (defun elpher-get-gemini-page (renderer)
916 "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
917 (let* ((address (elpher-page-address elpher-current-page))
918 (content (elpher-get-cached-content address)))
919 (condition-case the-error
920 (if (and content (funcall renderer nil))
921 (elpher-with-clean-buffer
923 (elpher-restore-pos))
924 (elpher-with-clean-buffer
925 (insert "LOADING GEMINI... (use 'u' to cancel)"))
926 (setq elpher-gemini-redirect-chain nil)
927 (elpher-get-gemini-response address renderer))
929 (elpher-network-error address the-error)))))
932 (defun elpher-render-gemini (body &optional mime-type-string)
933 "Render gemini response BODY with rendering MIME-TYPE-STRING."
936 (let* ((mime-type-string* (if (or (not mime-type-string)
937 (string-empty-p mime-type-string))
938 "text/gemini; charset=utf-8"
940 (mime-type-split (split-string mime-type-string* ";" t))
941 (mime-type (string-trim (car mime-type-split)))
942 (parameters (mapcar (lambda (s)
943 (let ((key-val (split-string s "=")))
944 (list (downcase (string-trim (car key-val)))
945 (downcase (string-trim (cadr key-val))))))
946 (cdr mime-type-split))))
947 (when (string-prefix-p "text/" mime-type)
948 (setq body (decode-coding-string
950 (if (assoc "charset" parameters)
951 (intern (cadr (assoc "charset" parameters)))
953 (setq body (replace-regexp-in-string "\r" "" body)))
955 ((or "text/gemini" "")
956 (elpher-render-gemini-map body parameters))
958 (elpher-render-html body))
959 ((pred (string-prefix-p "text/"))
960 (elpher-render-gemini-plain-text body parameters))
961 ((pred (string-prefix-p "image/"))
962 (elpher-render-image body))
964 (error "Unsupported MIME type %S" mime-type))))))
966 (defun elpher-gemini-get-link-url (line)
967 "Extract the url portion of LINE, a gemini map file link line."
968 (string-trim (elt (split-string (substring line 2)) 0)))
970 (defun elpher-gemini-get-link-display-string (line)
971 "Extract the display string portion of LINE, a gemini map file link line."
972 (let* ((rest (string-trim (elt (split-string line "=>") 1)))
973 (idx (string-match "[ \t]" rest)))
975 (string-trim (substring rest (+ idx 1)))
978 (defun elpher-collapse-dot-sequences (filename)
979 "Collapse dot sequences in FILENAME.
980 For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
981 (let* ((path (split-string filename "/"))
982 (path-reversed-normalized
983 (seq-reduce (lambda (a b)
984 (cond ((and a (equal b "..") (cdr a)))
985 ((and (not a) (equal b "..")) a) ;leading .. are dropped
989 (string-join (reverse path-reversed-normalized) "/")))
991 (defun elpher-address-from-gemini-url (url)
992 "Extract address from URL with defaults as per gemini map files."
993 (let ((address (url-generic-parse-url url)))
994 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
995 (setf (url-fullness address) t)
996 (if (url-host address) ;if there is an explicit host, filenames are absolute
997 (if (string-empty-p (url-filename address))
998 (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
999 (setf (url-host address) (url-host (elpher-page-address elpher-current-page)))
1000 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
1001 (setf (url-filename address)
1002 (concat (file-name-directory
1003 (url-filename (elpher-page-address elpher-current-page)))
1004 (url-filename address)))))
1005 (unless (url-type address)
1006 (setf (url-type address) "gemini"))
1007 (if (equal (url-type address) "gemini")
1008 (setf (url-filename address)
1009 (elpher-collapse-dot-sequences (url-filename address)))))
1012 (defun elpher-render-gemini-map (data _parameters)
1013 "Render DATA as a gemini map file, PARAMETERS is currently unused."
1014 (elpher-with-clean-buffer
1015 (dolist (line (split-string data "\n"))
1016 (if (string-prefix-p "=>" line)
1017 (let* ((url (elpher-gemini-get-link-url line))
1018 (display-string (elpher-gemini-get-link-display-string line))
1019 (address (elpher-address-from-gemini-url url)))
1020 (if (> (length display-string) 0)
1021 (elpher-insert-index-record display-string address)
1022 (elpher-insert-index-record url address)))
1023 (elpher-insert-index-record line)))
1024 (elpher-cache-content
1025 (elpher-page-address elpher-current-page)
1028 (defun elpher-render-gemini-plain-text (data _parameters)
1029 "Render DATA as plain text file. PARAMETERS is currently unused."
1030 (elpher-with-clean-buffer
1031 (insert (elpher-process-text-for-display data))
1032 (elpher-cache-content
1033 (elpher-page-address elpher-current-page)
1036 ;; Other URL page opening
1038 (defun elpher-get-other-url-page (renderer)
1039 "Getter which attempts to open the URL specified by the current page (RENDERER must be nil)."
1041 (elpher-visit-previous-page)
1042 (error "Command not supported for general URLs"))
1043 (let* ((address (elpher-page-address elpher-current-page))
1044 (url (elpher-address-to-url address)))
1046 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1047 (message "Opening URL...")
1048 (if elpher-open-urls-with-eww
1050 (browse-url url)))))
1052 ;; Telnet page connection
1054 (defun elpher-get-telnet-page (renderer)
1055 "Opens a telnet connection to the current page address (RENDERER must be nil)."
1057 (elpher-visit-previous-page)
1058 (error "Command not supported for telnet URLs"))
1059 (let* ((address (elpher-page-address elpher-current-page))
1060 (host (elpher-address-host address))
1061 (port (elpher-address-port address)))
1062 (elpher-visit-previous-page)
1067 ;; Start page page retrieval
1069 (defun elpher-get-start-page (renderer)
1070 "Getter which displays the start page (RENDERER must be nil)."
1072 (elpher-visit-previous-page)
1073 (error "Command not supported for start page"))
1074 (elpher-with-clean-buffer
1075 (insert " --------------------------------------------\n"
1076 " Elpher Gopher Client \n"
1077 " version " elpher-version "\n"
1078 " --------------------------------------------\n"
1080 "Default bindings:\n"
1082 " - TAB/Shift-TAB: next/prev item on current page\n"
1083 " - RET/mouse-1: open item under cursor\n"
1084 " - m: select an item on current page by name (autocompletes)\n"
1085 " - u/mouse-3: return to previous page\n"
1086 " - o/O: visit different selector or the root menu of the current server\n"
1087 " - g: go to a particular gopher address\n"
1088 " - d/D: download item under cursor or current page\n"
1089 " - i/I: info on item under cursor or current page\n"
1090 " - c/C: copy URL representation of item under cursor or current page\n"
1091 " - a/A: bookmark the item under cursor or current page\n"
1092 " - x/X: remove bookmark for item under cursor or current page\n"
1093 " - B: visit the bookmarks page\n"
1094 " - r: redraw current page (using cached contents if available)\n"
1095 " - R: reload current page (regenerates cache)\n"
1096 " - S: set character coding system for gopher (default is to autodetect)\n"
1097 " - T: toggle TLS gopher mode\n"
1098 " - .: display the raw server response for the current page\n"
1100 "Start your exploration of gopher space:\n")
1101 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1102 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1104 "Alternatively, select the following item and enter some search terms:\n")
1105 (elpher-insert-index-record "Veronica-2 Gopher Search Engine"
1106 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1108 "This page contains your bookmarked sites (also visit with B):\n")
1109 (elpher-insert-index-record "Your Bookmarks" 'bookmarks)
1111 "For Elpher release news or to leave feedback, visit:\n")
1112 (elpher-insert-index-record "The Elpher Project Page"
1113 (elpher-make-gopher-address ?1
1119 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1120 (insert-text-button "Elpher info manual"
1126 'help-echo help-string))
1127 (insert " for the full documentation. **\n")
1129 (concat " (This should be available if you have installed Elpher using\n"
1130 " MELPA. Otherwise you will have to install the manual yourself.)\n")
1132 (elpher-restore-pos)))
1134 ;; Bookmarks page page retrieval
1136 (defun elpher-get-bookmarks-page (renderer)
1137 "Getter to load and display the current bookmark list (RENDERER must be nil)."
1139 (elpher-visit-previous-page)
1140 (error "Command not supported for bookmarks page"))
1141 (elpher-with-clean-buffer
1142 (insert "---- Bookmark list ----\n\n")
1143 (let ((bookmarks (elpher-load-bookmarks)))
1145 (dolist (bookmark bookmarks)
1146 (let ((display-string (elpher-bookmark-display-string bookmark))
1147 (address (elpher-address-from-url (elpher-bookmark-url bookmark))))
1148 (elpher-insert-index-record display-string address)))
1149 (insert "No bookmarks found.\n")))
1150 (insert "\n-----------------------\n"
1152 "- u: return to previous page\n"
1153 "- x: delete selected bookmark\n"
1154 "- a: rename selected bookmark\n"
1156 "Bookmarks are stored in the file ")
1157 (let ((filename (locate-user-emacs-file "elpher-bookmarks"))
1158 (help-string "RET,mouse-1: Open bookmarks file in new buffer for editing."))
1159 (insert-text-button filename
1163 (find-file filename))
1165 'help-echo help-string))
1167 (elpher-restore-pos)))
1173 (defun elpher-make-bookmark (display-string url)
1174 "Make an elpher bookmark.
1175 DISPLAY-STRING determines how the bookmark will appear in the
1176 bookmark list, while URL is the url of the entry."
1177 (list display-string url))
1179 (defun elpher-bookmark-display-string (bookmark)
1180 "Get the display string of BOOKMARK."
1183 (defun elpher-set-bookmark-display-string (bookmark display-string)
1184 "Set the display string of BOOKMARK to DISPLAY-STRING."
1185 (setcar bookmark display-string))
1187 (defun elpher-bookmark-url (bookmark)
1188 "Get the address for BOOKMARK."
1191 (defun elpher-save-bookmarks (bookmarks)
1192 "Record the bookmark list BOOKMARKS to the user's bookmark file.
1193 Beware that this completely replaces the existing contents of the file."
1194 (with-temp-file (locate-user-emacs-file "elpher-bookmarks")
1196 (insert "; Elpher bookmarks file\n\n"
1197 "; Bookmarks are stored as a list of (label URL) items.\n"
1198 "; Feel free to edit by hand, but take care to ensure\n"
1199 "; the list structure remains intact.\n\n")
1200 (pp bookmarks (current-buffer))))
1202 (defun elpher-load-bookmarks ()
1203 "Get the list of bookmarks from the users's bookmark file."
1207 (insert-file-contents (locate-user-emacs-file "elpher-bookmarks"))
1208 (goto-char (point-min))
1209 (read (current-buffer))))))
1210 (if (and bookmarks (listp (cadar bookmarks)))
1212 (message "Reading old bookmark file. (Will be updated on write.)")
1213 (mapcar (lambda (old-bm)
1215 (elpher-address-to-url (apply #'elpher-make-gopher-address
1220 (defun elpher-add-address-bookmark (address display-string)
1221 "Save a bookmark for ADDRESS with label DISPLAY-STRING.)))
1222 If ADDRESS is already bookmarked, update the label only."
1223 (let ((bookmarks (elpher-load-bookmarks))
1224 (url (elpher-address-to-url address)))
1225 (let ((existing-bookmark (rassoc (list url) bookmarks)))
1226 (if existing-bookmark
1227 (elpher-set-bookmark-display-string existing-bookmark display-string)
1228 (push (elpher-make-bookmark display-string url) bookmarks)))
1229 (elpher-save-bookmarks bookmarks)))
1231 (defun elpher-remove-address-bookmark (address)
1232 "Remove any bookmark to ADDRESS."
1233 (let ((url (elpher-address-to-url address)))
1234 (elpher-save-bookmarks
1235 (seq-filter (lambda (bookmark)
1236 (not (equal (elpher-bookmark-url bookmark) url)))
1237 (elpher-load-bookmarks)))))
1239 ;;; Interactive procedures
1242 (defun elpher-next-link ()
1243 "Move point to the next link on the current page."
1247 (defun elpher-prev-link ()
1248 "Move point to the previous link on the current page."
1250 (backward-button 1))
1252 (defun elpher-follow-current-link ()
1253 "Open the link or url at point."
1257 (defun elpher-go (host-or-url)
1258 "Go to a particular gopher site HOST-OR-URL.
1259 When run interactively HOST-OR-URL is read from the minibuffer."
1260 (interactive "sGopher or Gemini URL: ")
1261 (let ((page (elpher-make-page host-or-url
1262 (elpher-address-from-url host-or-url))))
1263 (switch-to-buffer "*elpher*")
1264 (elpher-visit-page page)
1267 (defun elpher-go-current ()
1268 "Go to a particular site read from the minibuffer, initialized with the current URL."
1270 (let ((address (elpher-page-address elpher-current-page)))
1271 (if (elpher-address-special-p address)
1272 (error "Command invalid for this page")
1273 (let ((url (read-string "Gopher or Gemini URL: " (elpher-address-to-url address))))
1274 (elpher-visit-page (elpher-make-page url (elpher-address-from-url url)))))))
1276 (defun elpher-redraw ()
1277 "Redraw current page."
1279 (elpher-visit-page elpher-current-page))
1281 (defun elpher-reload ()
1282 "Reload current page."
1284 (elpher-reload-current-page))
1286 (defun elpher-toggle-tls ()
1287 "Toggle TLS encryption mode for gopher."
1289 (setq elpher-use-tls (not elpher-use-tls))
1291 (if (gnutls-available-p)
1292 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
1293 (setq elpher-use-tls nil)
1294 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
1295 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
1297 (defun elpher-view-raw ()
1298 "View raw server response for current page."
1300 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
1301 (error "This page was not generated by a server")
1302 (elpher-visit-page elpher-current-page
1303 #'elpher-render-raw)))
1305 (defun elpher-back ()
1306 "Go to previous site."
1308 (elpher-visit-previous-page))
1310 (defun elpher-download ()
1311 "Download the link at point."
1313 (let ((button (button-at (point))))
1315 (let ((page (button-get button 'elpher-page)))
1316 (if (elpher-address-special-p (elpher-page-address page))
1317 (error "Cannot download %s"
1318 (elpher-page-display-string page))
1319 (elpher-visit-page (button-get button 'elpher-page)
1320 #'elpher-render-download)))
1321 (error "No link selected"))))
1323 (defun elpher-download-current ()
1324 "Download the current page."
1326 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
1327 (error "Cannot download %s"
1328 (elpher-page-display-string elpher-current-page))
1329 (elpher-visit-page (elpher-make-page
1330 (elpher-page-display-string elpher-current-page)
1331 (elpher-page-address elpher-current-page)
1332 elpher-current-page)
1333 #'elpher-render-download
1336 (defun elpher-build-link-map ()
1337 "Build alist mapping link names to destination pages in current buffer."
1338 (let ((link-map nil)
1339 (b (next-button (point-min) t)))
1341 (push (cons (button-label b) b) link-map)
1342 (setq b (next-button (button-start b))))
1345 (defun elpher-jump ()
1346 "Select a directory entry by name. Similar to the info browser (m)enu command."
1348 (let* ((link-map (elpher-build-link-map)))
1350 (let ((key (let ((completion-ignore-case t))
1351 (completing-read "Directory item/link: "
1353 (if (and key (> (length key) 0))
1354 (let ((b (cdr (assoc key link-map))))
1355 (goto-char (button-start b))
1356 (button-activate b)))))))
1358 (defun elpher-root-dir ()
1359 "Visit root of current server."
1361 (let ((address (elpher-page-address elpher-current-page)))
1362 (if (not (elpher-address-special-p address))
1363 (if (or (member (url-filename address) '("/" ""))
1364 (and (elpher-address-gopher-p address)
1365 (= (length (elpher-gopher-address-selector address)) 0)))
1366 (error "Already at root directory of current server")
1367 (let ((address-copy (elpher-address-from-url
1368 (elpher-address-to-url address))))
1369 (setf (url-filename address-copy) "")
1371 (elpher-make-page (elpher-address-to-url address-copy)
1373 (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
1375 (defun elpher-bookmarks-current-p ()
1376 "Return non-nil if current page is a bookmarks page."
1377 (equal (elpher-address-type (elpher-page-address elpher-current-page))
1378 '(special bookmarks)))
1380 (defun elpher-reload-bookmarks ()
1381 "Reload bookmarks if current page is a bookmarks page."
1382 (if (elpher-bookmarks-current-p)
1383 (elpher-reload-current-page)))
1385 (defun elpher-bookmark-current ()
1386 "Bookmark the current page."
1388 (let ((address (elpher-page-address elpher-current-page))
1389 (display-string (elpher-page-display-string elpher-current-page)))
1390 (if (not (elpher-address-special-p address))
1391 (let ((bookmark-display-string (read-string "Bookmark display string: "
1393 (elpher-add-address-bookmark address bookmark-display-string)
1394 (message "Bookmark added."))
1395 (error "Cannot bookmark %s" display-string))))
1397 (defun elpher-bookmark-link ()
1398 "Bookmark the link at point."
1400 (let ((button (button-at (point))))
1402 (let* ((page (button-get button 'elpher-page))
1403 (address (elpher-page-address page))
1404 (display-string (elpher-page-display-string page)))
1405 (if (not (elpher-address-special-p address))
1406 (let ((bookmark-display-string (read-string "Bookmark display string: "
1408 (elpher-add-address-bookmark address bookmark-display-string)
1409 (elpher-reload-bookmarks)
1410 (message "Bookmark added."))
1411 (error "Cannot bookmark %s" display-string)))
1412 (error "No link selected"))))
1414 (defun elpher-unbookmark-current ()
1415 "Remove bookmark for the current page."
1417 (let ((address (elpher-page-address elpher-current-page)))
1418 (unless (elpher-address-special-p address)
1419 (elpher-remove-address-bookmark address)
1420 (message "Bookmark removed."))))
1422 (defun elpher-unbookmark-link ()
1423 "Remove bookmark for the link at point."
1425 (let ((button (button-at (point))))
1427 (let ((page (button-get button 'elpher-page)))
1428 (elpher-remove-address-bookmark (elpher-page-address page))
1429 (elpher-reload-bookmarks)
1430 (message "Bookmark removed."))
1431 (error "No link selected"))))
1433 (defun elpher-bookmarks ()
1434 "Visit bookmarks page."
1436 (switch-to-buffer "*elpher*")
1438 (elpher-make-page "Bookmarks Page" (elpher-make-special-address 'bookmarks))))
1440 (defun elpher-info-page (page)
1441 "Display information on PAGE."
1442 (let ((display-string (elpher-page-display-string page))
1443 (address (elpher-page-address page)))
1444 (if (elpher-address-special-p address)
1445 (message "Special page: %s" display-string)
1446 (message "%s" (elpher-address-to-url address)))))
1448 (defun elpher-info-link ()
1449 "Display information on page corresponding to link at point."
1451 (let ((button (button-at (point))))
1453 (elpher-info-page (button-get button 'elpher-page))
1454 (error "No item selected"))))
1456 (defun elpher-info-current ()
1457 "Display information on current page."
1459 (elpher-info-page elpher-current-page))
1461 (defun elpher-copy-page-url (page)
1462 "Copy URL representation of address of PAGE to `kill-ring'."
1463 (let ((address (elpher-page-address page)))
1464 (if (elpher-address-special-p address)
1465 (error (format "Cannot represent %s as URL" (elpher-page-display-string page)))
1466 (let ((url (elpher-address-to-url address)))
1467 (message "Copied \"%s\" to kill-ring/clipboard." url)
1470 (defun elpher-copy-link-url ()
1471 "Copy URL of item at point to `kill-ring'."
1473 (let ((button (button-at (point))))
1475 (elpher-copy-page-url (button-get button 'elpher-page))
1476 (error "No item selected"))))
1478 (defun elpher-copy-current-url ()
1479 "Copy URL of current page to `kill-ring'."
1481 (elpher-copy-page-url elpher-current-page))
1483 (defun elpher-set-gopher-coding-system ()
1484 "Specify an explicit character coding system for gopher selectors."
1486 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
1487 (setq elpher-user-coding-system system)
1489 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
1490 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
1496 (defvar elpher-mode-map
1497 (let ((map (make-sparse-keymap)))
1498 (define-key map (kbd "TAB") 'elpher-next-link)
1499 (define-key map (kbd "<backtab>") 'elpher-prev-link)
1500 (define-key map (kbd "u") 'elpher-back)
1501 (define-key map [mouse-3] 'elpher-back)
1502 (define-key map (kbd "O") 'elpher-root-dir)
1503 (define-key map (kbd "g") 'elpher-go)
1504 (define-key map (kbd "o") 'elpher-go-current)
1505 (define-key map (kbd "r") 'elpher-redraw)
1506 (define-key map (kbd "R") 'elpher-reload)
1507 (define-key map (kbd "T") 'elpher-toggle-tls)
1508 (define-key map (kbd ".") 'elpher-view-raw)
1509 (define-key map (kbd "d") 'elpher-download)
1510 (define-key map (kbd "D") 'elpher-download-current)
1511 (define-key map (kbd "m") 'elpher-jump)
1512 (define-key map (kbd "i") 'elpher-info-link)
1513 (define-key map (kbd "I") 'elpher-info-current)
1514 (define-key map (kbd "c") 'elpher-copy-link-url)
1515 (define-key map (kbd "C") 'elpher-copy-current-url)
1516 (define-key map (kbd "a") 'elpher-bookmark-link)
1517 (define-key map (kbd "A") 'elpher-bookmark-current)
1518 (define-key map (kbd "x") 'elpher-unbookmark-link)
1519 (define-key map (kbd "X") 'elpher-unbookmark-current)
1520 (define-key map (kbd "B") 'elpher-bookmarks)
1521 (define-key map (kbd "S") 'elpher-set-gopher-coding-system)
1522 (when (fboundp 'evil-define-key*)
1523 (evil-define-key* 'motion map
1524 (kbd "TAB") 'elpher-next-link
1525 (kbd "C-") 'elpher-follow-current-link
1526 (kbd "C-t") 'elpher-back
1527 (kbd "u") 'elpher-back
1528 [mouse-3] 'elpher-back
1529 (kbd "g") 'elpher-go
1530 (kbd "o") 'elpher-go-current
1531 (kbd "r") 'elpher-redraw
1532 (kbd "R") 'elpher-reload
1533 (kbd "T") 'elpher-toggle-tls
1534 (kbd ".") 'elpher-view-raw
1535 (kbd "d") 'elpher-download
1536 (kbd "D") 'elpher-download-current
1537 (kbd "m") 'elpher-jump
1538 (kbd "i") 'elpher-info-link
1539 (kbd "I") 'elpher-info-current
1540 (kbd "c") 'elpher-copy-link-url
1541 (kbd "C") 'elpher-copy-current-url
1542 (kbd "a") 'elpher-bookmark-link
1543 (kbd "A") 'elpher-bookmark-current
1544 (kbd "x") 'elpher-unbookmark-link
1545 (kbd "X") 'elpher-unbookmark-current
1546 (kbd "B") 'elpher-bookmarks
1547 (kbd "S") 'elpher-set-gopher-coding-system))
1549 "Keymap for gopher client.")
1551 (define-derived-mode elpher-mode special-mode "elpher"
1552 "Major mode for elpher, an elisp gopher client.
1554 This mode is automatically enabled by the interactive
1555 functions which initialize the gopher client, namely
1556 `elpher', `elpher-go' and `elpher-bookmarks'.")
1558 (when (fboundp 'evil-set-initial-state)
1559 (evil-set-initial-state 'elpher-mode 'motion))
1562 ;;; Main start procedure
1567 "Start elpher with default landing page."
1569 (if (get-buffer "*elpher*")
1570 (switch-to-buffer "*elpher*")
1571 (switch-to-buffer "*elpher*")
1572 (setq elpher-current-page nil)
1573 (let ((start-page (elpher-make-page "Elpher Start Page"
1574 (elpher-make-special-address 'start))))
1575 (elpher-visit-page start-page)))
1576 "Started Elpher.") ; Otherwise (elpher) evaluates to start page string.
1578 ;;; elpher.el ends here