1 ;;; elpher.el --- A friendly gopher client. -*- lexical-binding:t -*-
3 ;; Copyright (C) 2019 Tim Vaughan
5 ;; Author: Tim Vaughan <tgvaughan@gmail.com>
6 ;; Created: 11 April 2019
8 ;; Keywords: comm gopher
9 ;; Homepage: https://github.com/tgvaughan/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 ;; - basic support for 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!
68 (defconst elpher-version "2.3.6"
69 "Current version of elpher.")
71 (defconst elpher-margin-width 6
72 "Width of left-hand margin used when rendering indicies.")
74 (defconst elpher-type-map
75 '(((gopher ?0) elpher-get-gopher-node elpher-render-text "txt" elpher-text)
76 ((gopher ?1) elpher-get-gopher-node elpher-render-index "/" elpher-index)
77 ((gopher ?4) elpher-get-gopher-node elpher-render-download "bin" elpher-binary)
78 ((gopher ?5) elpher-get-gopher-node elpher-render-download "bin" elpher-binary)
79 ((gopher ?7) elpher-get-gopher-query-node elpher-render-index "?" elpher-search)
80 ((gopher ?9) elpher-get-gopher-node elpher-render-download "bin" elpher-binary)
81 ((gopher ?g) elpher-get-gopher-node elpher-render-image "img" elpher-image)
82 ((gopher ?p) elpher-get-gopher-node elpher-render-image "img" elpher-image)
83 ((gopher ?I) elpher-get-gopher-node elpher-render-image "img" elpher-image)
84 ((gopher ?d) elpher-get-gopher-node elpher-render-download "doc" elpher-binary)
85 ((gopher ?P) elpher-get-gopher-node elpher-render-download "doc" elpher-binary)
86 ((gopher ?s) elpher-get-gopher-node elpher-render-download "snd" elpher-binary)
87 ((gopher ?h) elpher-get-gopher-node elpher-render-html "htm" elpher-html)
88 (gemini elpher-get-gemini-node elpher-render-gemini "gem" elpher-gemini)
89 (telnet elpher-get-telnet-node nil "tel" elpher-telnet)
90 (other-url elpher-get-other-url-node nil "url" elpher-other-url)
91 ((special bookmarks) elpher-get-bookmarks-node nil "/" elpher-index)
92 ((special start) elpher-get-start-node nil))
93 "Association list from types to getters, renderers, margin codes and index faces.")
96 ;;; Customization group
101 :group 'applications)
103 ;; Face customizations
105 (defface elpher-index
106 '((t :inherit font-lock-keyword-face))
107 "Face used for directory type directory records.")
111 "Face used for text type directory records.")
114 '((t :inherit default))
115 "Face used for info type directory records.")
117 (defface elpher-image
118 '((t :inherit font-lock-string-face))
119 "Face used for image type directory records.")
121 (defface elpher-search
122 '((t :inherit warning))
123 "Face used for search type directory records.")
126 '((t :inherit font-lock-comment-face))
127 "Face used for html type directory records.")
129 (defface elpher-gemini
130 '((t :inherit font-lock-regexp-grouping-backslash))
131 "Face used for html type directory records.")
133 (defface elpher-other-url
134 '((t :inherit font-lock-comment-face))
135 "Face used for other URL type links records.")
137 (defface elpher-telnet
138 '((t :inherit font-lock-function-name-face))
139 "Face used for telnet type directory records.")
141 (defface elpher-binary
142 '((t :inherit font-lock-doc-face))
143 "Face used for binary type directory records.")
145 (defface elpher-unknown
146 '((t :inherit error))
147 "Face used for directory records with unknown/unsupported types.")
149 (defface elpher-margin-key
151 "Face used for directory margin key.")
153 (defface elpher-margin-brackets
154 '((t :inherit shadow))
155 "Face used for brackets around directory margin key.")
157 ;; Other customizations
159 (defcustom elpher-open-urls-with-eww nil
160 "If non-nil, open URL selectors using eww.
161 Otherwise, use the system browser via the BROWSE-URL function."
164 (defcustom elpher-buttonify-urls-in-directories t
165 "If non-nil, turns URLs matched in directories into clickable buttons."
168 (defcustom elpher-use-header t
169 "If non-nil, display current node information in buffer header."
172 (defcustom elpher-auto-disengage-TLS nil
173 "If non-nil, automatically disengage TLS following an unsuccessful connection.
174 While enabling this may seem convenient, it is also potentially dangerous as it
175 allows switching from an encrypted channel back to plain text without user input."
184 ;; An elpher "address" object is either a url object or a symbol.
185 ;; Symbol addresses are "special", corresponding to pages generated
186 ;; dynamically for and by elpher. All others represent pages which
187 ;; rely on content retrieved over the network.
189 (defun elpher-address-from-url (url-string)
190 "Create a ADDRESS object corresponding to the given URL-STRING."
191 (let ((data (match-data))) ; Prevent parsing clobbering match data
193 (let ((url (url-generic-parse-url url-string)))
194 (unless (and (not (url-fullness url)) (url-type url))
195 (setf (url-fullness url) t)
196 (setf (url-filename url)
197 (url-unhex-string (url-filename url)))
198 (unless (url-type url)
199 (setf (url-type url) "gopher"))
200 (when (or (equal "gopher" (url-type url))
201 (equal "gophers" (url-type url)))
203 (unless (url-host url)
204 (setf (url-host url) (url-filename url))
205 (setf (url-filename url) ""))
206 (when (or (equal (url-filename url) "")
207 (equal (url-filename url) "/"))
208 (setf (url-filename url) "/1")))
209 (when (equal "gemini" (url-type url))
211 (if (equal (url-filename url) "")
212 (setf (url-filename url) "/"))))
214 (set-match-data data))))
216 (defun elpher-make-gopher-address (type selector host port &optional tls)
217 "Create an ADDRESS object using gopher directory record attributes.
218 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
219 If the optional attribute TLS is non-nil, the address will be marked as
220 requiring gopher-over-TLS."
222 ((and (equal type ?h)
223 (string-prefix-p "URL:" selector))
224 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
226 (elpher-address-from-url
229 ":" (number-to-string port))))
231 (elpher-address-from-url
232 (concat "gopher" (if tls "s" "")
234 ":" (number-to-string port)
238 (defun elpher-make-special-address (type)
239 "Create an ADDRESS object corresponding to the given special page symbol TYPE."
242 (defun elpher-address-to-url (address)
243 "Get string representation of ADDRESS, or nil if ADDRESS is special."
244 (if (not (elpher-address-special-p address))
245 (url-encode-url (url-recreate-url address))
248 (defun elpher-address-type (address)
249 "Retrieve type of ADDRESS object.
250 This is used to determine how to retrieve and render the document the
251 address refers to, via the table `elpher-type-map'."
252 (if (symbolp address)
253 (list 'special address)
254 (let ((protocol (url-type address)))
255 (cond ((or (equal protocol "gopher")
256 (equal protocol "gophers"))
258 (if (member (url-filename address) '("" "/"))
260 (string-to-char (substring (url-filename address) 1)))))
261 ((equal protocol "gemini")
263 ((equal protocol "telnet")
267 (defun elpher-address-protocol (address)
268 "Retrieve the transport protocol for ADDRESS. This is nil for special addresses."
269 (if (symbolp address)
273 (defun elpher-address-filename (address)
274 "Retrieve the filename component of ADDRESS.
275 For gopher addresses this is a combination of the selector type and selector."
276 (if (symbolp address)
278 (url-filename address)))
280 (defun elpher-address-host (address)
281 "Retrieve host from ADDRESS object."
284 (defun elpher-address-port (address)
285 "Retrieve port from ADDRESS object.
286 If no address is defined, returns 0. (This is for compatibility with the URL library.)"
287 (if (symbolp address)
291 (defun elpher-address-special-p (address)
292 "Return non-nil if ADDRESS object is special (e.g. start page, bookmarks page)."
295 (defun elpher-address-gopher-p (address)
296 "Return non-nill if ADDRESS object is a gopher address."
297 (and (not (elpher-address-special-p address))
298 (member (elpher-address-protocol address) '("gopher gophers"))))
300 (defun elpher-gopher-address-selector (address)
301 "Retrieve gopher selector from ADDRESS object."
302 (if (member (url-filename address) '("" "/"))
304 (substring (url-filename address) 2)))
308 (defun elpher-make-node (display-string address &optional parent)
309 "Create a node in the page hierarchy.
311 DISPLAY-STRING records the display string used for the page.
313 ADDRESS specifies the address object of the page.
315 The optional PARENT specifies the parent node in the hierarchy.
316 This is set every time the node is visited, so while it forms
317 an important part of the node data there is no need to set it
319 (list display-string address parent))
321 (defun elpher-node-display-string (node)
322 "Retrieve the display string of NODE."
325 (defun elpher-node-address (node)
326 "Retrieve the ADDRESS object of NODE."
329 (defun elpher-node-parent (node)
330 "Retrieve the parent node of NODE."
333 (defun elpher-set-node-parent (node parent)
334 "Set the parent node of NODE to be PARENT."
335 (setcar (cdr (cdr node)) parent))
339 (defvar elpher-content-cache (make-hash-table :test 'equal))
340 (defvar elpher-pos-cache (make-hash-table :test 'equal))
342 (defun elpher-get-cached-content (address)
343 "Retrieve the cached content for ADDRESS, or nil if none exists."
344 (gethash address elpher-content-cache))
346 (defun elpher-cache-content (address content)
347 "Set the content cache for ADDRESS to CONTENT."
348 (puthash address content elpher-content-cache))
350 (defun elpher-get-cached-pos (address)
351 "Retrieve the cached cursor position for ADDRESS, or nil if none exists."
352 (gethash address elpher-pos-cache))
354 (defun elpher-cache-pos (address pos)
355 "Set the cursor position cache for ADDRESS to POS."
356 (puthash address pos elpher-pos-cache))
358 ;; Node graph traversal
360 (defvar elpher-current-node nil)
362 (defun elpher-visit-node (node &optional renderer preserve-parent)
363 "Visit NODE using its own renderer or RENDERER, if non-nil.
364 Additionally, set the parent of NODE to `elpher-current-node',
365 unless PRESERVE-PARENT is non-nil."
367 (elpher-process-cleanup)
368 (unless preserve-parent
369 (if (and (elpher-node-parent elpher-current-node)
370 (equal (elpher-node-address elpher-current-node)
371 (elpher-node-address node)))
372 (elpher-set-node-parent node (elpher-node-parent elpher-current-node))
373 (elpher-set-node-parent node elpher-current-node)))
374 (setq elpher-current-node node)
375 (let* ((address (elpher-node-address node))
376 (type (elpher-address-type address))
377 (type-record (cdr (assoc type elpher-type-map))))
379 (funcall (car type-record)
383 (elpher-visit-parent-node)
385 (`(gopher ,type-char)
386 (error "Unsupported gopher selector type '%c' for '%s'"
387 type-char (elpher-address-to-url address)))
389 (error "Unsupported address type '%S' for '%s'"
390 other (elpher-address-to-url address)))))))
392 (defun elpher-visit-parent-node ()
393 "Visit the parent of the current node."
394 (let ((parent-node (elpher-node-parent elpher-current-node)))
396 (elpher-visit-node parent-node nil t))))
398 (defun elpher-reload-current-node ()
399 "Reload the current node, discarding any existing cached content."
400 (elpher-cache-content (elpher-node-address elpher-current-node) nil)
401 (elpher-visit-node elpher-current-node))
403 (defun elpher-save-pos ()
404 "Save the current position of point to the current node."
405 (when elpher-current-node
406 (elpher-cache-pos (elpher-node-address elpher-current-node) (point))))
408 (defun elpher-restore-pos ()
409 "Restore the position of point to that cached in the current node."
410 (let ((pos (elpher-get-cached-pos (elpher-node-address elpher-current-node))))
413 (goto-char (point-min)))))
416 ;;; Buffer preparation
419 (defun elpher-update-header ()
420 "If `elpher-use-header' is true, display current node info in window header."
421 (if elpher-use-header
422 (let* ((display-string (elpher-node-display-string elpher-current-node))
423 (address (elpher-node-address elpher-current-node))
424 (tls-string (if (and (not (elpher-address-special-p address))
425 (member (elpher-address-protocol address)
426 '("gophers" "gemini")))
429 (header (concat display-string
430 (propertize tls-string 'face 'bold))))
431 (setq header-line-format header))))
433 (defmacro elpher-with-clean-buffer (&rest args)
434 "Evaluate ARGS with a clean *elpher* buffer as current."
435 (list 'with-current-buffer "*elpher*"
437 (append (list 'let '((inhibit-read-only t))
439 '(elpher-update-header))
446 (defvar elpher-user-coding-system nil
447 "User-specified coding system to use for decoding text responses.")
449 (defun elpher-decode (string)
450 "Decode STRING using autodetected or user-specified coding system."
451 (decode-coding-string string
452 (if elpher-user-coding-system
453 elpher-user-coding-system
454 (detect-coding-string string t))))
456 (defun elpher-preprocess-text-response (string)
457 "Preprocess text selector response contained in STRING.
458 This involes decoding the character representation, and clearing
459 away CRs and any terminating period."
460 (elpher-decode (replace-regexp-in-string "\n\.\n$" "\n"
461 (replace-regexp-in-string "\r" "" string))))
464 ;;; Network error reporting
467 (defun elpher-network-error (address error)
468 "Display ERROR message following unsuccessful negotiation with ADDRESS."
469 (elpher-with-clean-buffer
470 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
471 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
472 (error-message-string error) "\n"
473 (propertize "\n----------------\n\n" 'face 'error)
474 "Press 'u' to return to the previous page.")))
477 ;;; Gopher selector retrieval
480 (defun elpher-process-cleanup ()
481 "Immediately shut down any extant elpher process."
482 (let ((p (get-process "elpher-process")))
483 (if p (delete-process p))))
485 (defvar elpher-use-tls nil
486 "If non-nil, use TLS to communicate with gopher servers.")
488 (defvar elpher-selector-string)
490 (defun elpher-get-selector (address after &optional propagate-error)
491 "Retrieve selector specified by ADDRESS, then execute AFTER.
492 The result is stored as a string in the variable ‘elpher-selector-string’.
494 Usually errors result in an error page being displayed. This is only
495 appropriate if the selector is to be directly viewed. If PROPAGATE-ERROR
496 is non-nil, this message is not displayed. Instead, the error propagates
497 up to the calling function."
498 (setq elpher-selector-string "")
499 (when (equal (elpher-address-protocol address) "gophers")
500 (if (gnutls-available-p)
501 (when (not elpher-use-tls)
502 (setq elpher-use-tls t)
503 (message "Engaging TLS gopher mode."))
504 (error "Cannot retrieve TLS gopher selector: GnuTLS not available")))
505 (condition-case the-error
506 (let* ((kill-buffer-query-functions nil)
507 (port (elpher-address-port address))
508 (proc (open-network-stream "elpher-process"
510 (elpher-address-host address)
511 (if (> port 0) port 70)
512 :type (if elpher-use-tls 'tls 'plain))))
513 (set-process-coding-system proc 'binary)
514 (set-process-filter proc
515 (lambda (_proc string)
516 (setq elpher-selector-string
517 (concat elpher-selector-string string))))
518 (set-process-sentinel proc after)
519 (let ((inhibit-eol-conversion t))
520 (process-send-string proc
521 (concat (elpher-gopher-address-selector address) "\r\n"))))
523 (if (and (consp the-error)
524 (eq (car the-error) 'gnutls-error)
525 (not (equal (elpher-address-protocol address) "gophers"))
526 (or elpher-auto-disengage-TLS
527 (yes-or-no-p "Could not establish encrypted connection. Disable TLS mode? ")))
529 (message "Disengaging TLS gopher mode.")
530 (setq elpher-use-tls nil)
531 (elpher-get-selector address after))
532 (elpher-process-cleanup)
535 (elpher-with-clean-buffer
536 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
537 "Failed to connect to " (elpher-address-to-url address) ".\n"
538 (propertize "\n----------------\n\n" 'face 'error)
539 "Press 'u' to return to the previous page.")))))))
541 (defun elpher-get-gopher-node (renderer)
542 "Getter function for gopher nodes.
543 The RENDERER procedure is used to display the contents of the node
544 once they are retrieved from the gopher server."
545 (let* ((address (elpher-node-address elpher-current-node))
546 (content (elpher-get-cached-content address)))
547 (if (and content (funcall renderer nil))
548 (elpher-with-clean-buffer
550 (elpher-restore-pos))
551 (elpher-with-clean-buffer
552 (insert "LOADING... (use 'u' to cancel)"))
553 (elpher-get-selector address
554 (lambda (_proc event)
555 (unless (string-prefix-p "deleted" event)
556 (funcall renderer elpher-selector-string)
557 (elpher-restore-pos)))))))
561 (defun elpher-insert-index (string)
562 "Insert the index corresponding to STRING into the current buffer."
563 ;; Should be able to split directly on CRLF, but some non-conformant
564 ;; LF-only servers sadly exist, hence the following.
565 (let ((str-processed (elpher-preprocess-text-response string)))
566 (dolist (line (split-string str-processed "\n"))
568 (unless (= (length line) 0)
569 (let* ((type (elt line 0))
570 (fields (split-string (substring line 1) "\t"))
571 (display-string (elt fields 0))
572 (selector (elt fields 1))
573 (host (elt fields 2))
574 (port (if (elt fields 3)
575 (string-to-number (elt fields 3))
577 (address (elpher-make-gopher-address type selector host port)))
578 (elpher-insert-index-record display-string address)))))))
580 (defun elpher-insert-margin (&optional type-name)
581 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
584 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
586 (propertize "[" 'face 'elpher-margin-brackets)
587 (propertize type-name 'face 'elpher-margin-key)
588 (propertize "]" 'face 'elpher-margin-brackets))))
590 (insert (make-string elpher-margin-width ?\s))))
592 (defun elpher-node-button-help (node)
593 "Return a string containing the help text for a button corresponding to NODE."
594 (let ((address (elpher-node-address node)))
595 (format "mouse-1, RET: open '%s'" (if (elpher-address-special-p address)
597 (elpher-address-to-url address)))))
599 (defun elpher-insert-index-record (display-string &optional address)
600 "Function to insert an index record into the current buffer.
601 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
602 If ADDRESS is not supplied or nil the record is rendered as an
604 (let* ((type (if address (elpher-address-type address) nil))
605 (type-map-entry (cdr (assoc type elpher-type-map))))
607 (let* ((margin-code (elt type-map-entry 2))
608 (face (elt type-map-entry 3))
609 (node (elpher-make-node display-string address)))
610 (elpher-insert-margin margin-code)
611 (insert-text-button display-string
614 'action #'elpher-click-link
616 'help-echo (elpher-node-button-help node)))
618 ((or '(gopher ?i) 'nil) ;; Information
619 (elpher-insert-margin)
620 (let ((propertized-display-string
621 (propertize display-string 'face 'elpher-info)))
622 (insert (if elpher-buttonify-urls-in-directories
623 (elpher-buttonify-urls propertized-display-string)
624 propertized-display-string))))
625 (`(gopher ,selector-type) ;; Unknown
626 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
627 (insert (propertize display-string
628 'face 'elpher-unknown)))))
631 (defun elpher-click-link (button)
632 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
633 (let ((node (button-get button 'elpher-node)))
634 (elpher-visit-node node)))
636 (defun elpher-render-index (data &optional _mime-type-string)
637 "Render DATA as an index. MIME-TYPE-STRING is unused."
638 (elpher-with-clean-buffer
641 (elpher-insert-index data)
642 (elpher-cache-content (elpher-node-address elpher-current-node)
647 (defconst elpher-url-regex
648 "\\([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\-_~?/@|]\\)?\\)?"
649 "Regexp used to locate and buttniofy URLs in text files loaded by elpher.")
651 (defun elpher-buttonify-urls (string)
652 "Turn substrings which look like urls in STRING into clickable buttons."
655 (goto-char (point-min))
656 (while (re-search-forward elpher-url-regex nil t)
657 (let ((node (elpher-make-node (substring-no-properties (match-string 0))
658 (elpher-address-from-url (match-string 0)))))
659 (make-text-button (match-beginning 0)
662 'action #'elpher-click-link
664 'help-echo (elpher-node-button-help node)
668 (defun elpher-render-text (data &optional _mime-type-string)
669 "Render DATA as text. MIME-TYPE-STRING is unused."
670 (elpher-with-clean-buffer
673 (insert (elpher-buttonify-urls (elpher-preprocess-text-response data)))
674 (elpher-cache-content
675 (elpher-node-address elpher-current-node)
680 (defun elpher-render-image (data &optional _mime-type-string)
681 "Display DATA as image. MIME-TYPE-STRING is unused."
684 (if (display-images-p)
686 (let ((image (create-image
689 (elpher-with-clean-buffer
691 (elpher-restore-pos))))
692 (elpher-render-download data))))
694 ;; Search retrieval and rendering
696 (defun elpher-get-gopher-query-node (renderer)
697 "Getter for gopher addresses requiring input.
698 The response is rendered using the rendering function RENDERER."
699 (let* ((address (elpher-node-address elpher-current-node))
700 (content (elpher-get-cached-content address))
702 (if (and content (funcall renderer nil))
703 (elpher-with-clean-buffer
706 (message "Displaying cached search results. Reload to perform a new search."))
708 (let* ((query-string (read-string "Query: "))
709 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
710 (search-address (elpher-make-gopher-address ?1
712 (elpher-address-host address)
713 (elpher-address-port address)
714 (equal (elpher-address-type address) "gophers"))))
717 (elpher-with-clean-buffer
718 (insert "LOADING RESULTS... (use 'u' to cancel)"))
719 (elpher-get-selector search-address
720 (lambda (_proc event)
721 (unless (string-prefix-p "deleted" event)
722 (funcall renderer elpher-selector-string)
723 (elpher-restore-pos)))))
725 (elpher-visit-parent-node))))))
727 ;; Raw server response rendering
729 (defun elpher-render-raw (data &optional _mime-type-string)
730 "Display raw DATA in buffer. MIME-TYPE-STRING is unused."
733 (elpher-with-clean-buffer
735 (goto-char (point-min)))
736 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
738 ;; File save "rendering"
740 (defun elpher-render-download (data &optional _mime-type-string)
741 "Save DATA to file. MIME-TYPE-STRING is unused."
744 (let* ((address (elpher-node-address elpher-current-node))
745 (selector (elpher-gopher-address-selector address)))
746 (elpher-visit-parent-node) ; Do first in case of non-local exits.
747 (let* ((filename-proposal (file-name-nondirectory selector))
748 (filename (read-file-name "Download complete. Save file as: "
750 (if (> (length filename-proposal) 0)
753 (let ((coding-system-for-write 'binary))
754 (with-temp-file filename
756 (message (format "Saved to file %s." filename))))))
760 (defun elpher-render-html (data &optional _mime-type-string)
761 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
762 (elpher-with-clean-buffer
765 (let ((dom (with-temp-buffer
767 (libxml-parse-html-region (point-min) (point-max)))))
768 (shr-insert-document dom)))))
770 ;; Gemini node retrieval
772 (defvar elpher-gemini-response)
773 (defvar elpher-gemini-redirect-chain)
775 (defun elpher-get-gemini-response (address after)
776 "Retrieve gemini ADDRESS, then execute AFTER.
777 The response is stored in the variable ‘elpher-gemini-response’."
778 (setq elpher-gemini-response "")
779 (if (not (gnutls-available-p))
780 (error "Cannot establish gemini connection: GnuTLS not available")
781 (condition-case the-error
782 (let* ((kill-buffer-query-functions nil)
783 (network-security-level 'medium)
784 (port (elpher-address-port address))
785 (proc (open-network-stream "elpher-process"
787 (elpher-address-host address)
788 (if (> port 0) port 1965)
790 (set-process-coding-system proc 'binary)
791 (set-process-filter proc
792 (lambda (_proc string)
793 (setq elpher-gemini-response
794 (concat elpher-gemini-response string))))
795 (set-process-sentinel proc after)
796 (let ((inhibit-eol-conversion t))
797 (process-send-string proc
798 (concat (elpher-address-to-url address) "\r\n"))))
800 (error "Error initiating connection to server")))))
802 (defun elpher-parse-gemini-response (response)
803 "Parse the RESPONSE string and return a list of components
804 The list is of the form (code meta body). A response of nil implies
805 that the response was malformed."
806 (let ((header-end-idx (string-match "\r\n" response)))
808 (let ((header (string-trim (substring response 0 header-end-idx)))
809 (body (substring response (+ header-end-idx 2))))
810 (if (>= (length header) 2)
811 (let ((code (substring header 0 2))
812 (meta (string-trim (substring header 2))))
813 (list code meta body))
814 (error "Malformed response: No response status found in header %s" header)))
815 (error "Malformed response: No CRLF-delimited header found"))))
818 (defun elpher-process-gemini-response (renderer)
819 "Process the gemini response and pass the result to RENDERER.
820 The response is assumed to be in the variable `elpher-gemini-response'."
821 (condition-case the-error
822 (let ((response-components (elpher-parse-gemini-response elpher-gemini-response)))
823 (let ((response-code (elt response-components 0))
824 (response-meta (elt response-components 1))
825 (response-body (elt response-components 2)))
826 (pcase (elt response-code 0)
828 (elpher-with-clean-buffer
829 (insert "Gemini server is requesting input."))
830 (let* ((query-string (read-string (concat response-meta ": ")))
831 (url (elpher-address-to-url (elpher-node-address elpher-current-node)))
832 (query-address (elpher-address-from-url (concat url "?" query-string))))
833 (elpher-get-gemini-response query-address
834 (lambda (_proc event)
835 (unless (string-prefix-p "deleted" event)
836 (funcall #'elpher-process-gemini-response
838 (elpher-restore-pos))))))
839 (?2 ; Normal response
840 ;; (message response-header)
841 (funcall renderer response-body response-meta))
843 (message "Following redirect to %s" response-meta)
844 (if (>= (length elpher-gemini-redirect-chain) 5)
845 (error "More than 5 consecutive redirects followed"))
846 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
847 (if (member redirect-address elpher-gemini-redirect-chain)
848 (error "Redirect loop detected"))
849 (if (not (string= (elpher-address-protocol redirect-address)
851 (error "Server tried to automatically redirect to non-gemini URL: %s"
853 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
854 (elpher-get-gemini-response redirect-address
855 (lambda (_proc event)
856 (unless (string-prefix-p "deleted" event)
857 (funcall #'elpher-process-gemini-response
859 (elpher-restore-pos))))))
860 (?4 ; Temporary failure
861 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
862 response-code response-meta))
863 (?5 ; Permanent failure
864 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
865 response-code response-meta))
866 (?6 ; Client certificate required
867 (error "Gemini server requires client certificate (unsupported at this time)"))
869 (error "Gemini server response unknown: %s %s"
870 response-code response-meta)))))
872 (elpher-network-error (elpher-node-address elpher-current-node) the-error))))
874 (defun elpher-get-gemini-node (renderer)
875 "Getter which retrieves and renders a Gemini node and renders it using RENDERER."
876 (let* ((address (elpher-node-address elpher-current-node))
877 (content (elpher-get-cached-content address)))
878 (condition-case the-error
879 (if (and content (funcall renderer nil))
880 (elpher-with-clean-buffer
882 (elpher-restore-pos))
883 (elpher-with-clean-buffer
884 (insert "LOADING GEMINI... (use 'u' to cancel)"))
885 (setq elpher-gemini-redirect-chain nil)
886 (elpher-get-gemini-response address
887 (lambda (_proc event)
888 (unless (string-prefix-p "deleted" event)
889 (funcall #'elpher-process-gemini-response
891 (elpher-restore-pos)))))
893 (elpher-network-error address the-error)))))
896 (defun elpher-render-gemini (body &optional mime-type-string)
897 "Render gemini response BODY with rendering MIME-TYPE-STRING."
900 (let* ((mime-type-string* (if (or (not mime-type-string)
901 (string-empty-p mime-type-string))
902 "text/gemini; charset=utf-8"
904 (mime-type-split (split-string mime-type-string* ";" t))
905 (mime-type (string-trim (car mime-type-split)))
906 (parameters (mapcar (lambda (s)
907 (let ((key-val (split-string s "=")))
908 (list (downcase (string-trim (car key-val)))
909 (downcase (string-trim (cadr key-val))))))
910 (cdr mime-type-split))))
911 (when (string-prefix-p "text/" mime-type)
912 (setq body (decode-coding-string
914 (if (assoc "charset" parameters)
915 (intern (cadr (assoc "charset" parameters)))
917 (setq body (replace-regexp-in-string "\r" "" body)))
919 ((or "text/gemini" "")
920 (elpher-render-gemini-map body parameters))
921 ((pred (string-prefix-p "text/"))
922 (elpher-render-gemini-plain-text body parameters))
923 ((pred (string-prefix-p "image/"))
924 (elpher-render-image body))
926 (error "Unsupported MIME type %S" mime-type))))))
928 (defun elpher-gemini-get-link-url (line)
929 "Extract the url portion of LINE, a gemini map file link line."
930 (string-trim (elt (split-string (substring line 2)) 0)))
932 (defun elpher-gemini-get-link-display-string (line)
933 "Extract the display string portion of LINE, a gemini map file link line."
934 (let* ((rest (string-trim (elt (split-string line "=>") 1)))
935 (idx (string-match "[ \t]" rest)))
937 (string-trim (substring rest (+ idx 1)))
940 (defun elpher-collapse-dot-sequences (filename)
941 "Collapse dot sequences in FILENAME.
942 For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
943 (let* ((path (split-string filename "/"))
944 (path-reversed-normalized
945 (seq-reduce (lambda (a b)
946 (cond ((and a (equal b "..") (cdr a)))
947 ((and (not a) (equal b "..")) a) ;leading .. are dropped
951 (string-join (reverse path-reversed-normalized) "/")))
953 (defun elpher-address-from-gemini-url (url)
954 "Extract address from URL with defaults as per gemini map files."
955 (let ((address (url-generic-parse-url url)))
956 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
957 (setf (url-fullness address) t)
958 (unless (url-host address) ;if there is an explicit host, filenames are absolute
959 (setf (url-host address) (url-host (elpher-node-address elpher-current-node)))
960 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
961 (setf (url-filename address)
962 (concat (file-name-directory
963 (url-filename (elpher-node-address elpher-current-node)))
964 (url-filename address)))))
965 (unless (url-type address)
966 (setf (url-type address) "gemini"))
967 (if (equal (url-type address) "gemini")
968 (setf (url-filename address)
969 (elpher-collapse-dot-sequences (url-filename address)))))
972 (defun elpher-render-gemini-map (data _parameters)
973 "Render DATA as a gemini map file, PARAMETERS is currently unused."
974 (elpher-with-clean-buffer
975 (dolist (line (split-string data "\n"))
976 (if (string-prefix-p "=>" line)
977 (let* ((url (elpher-gemini-get-link-url line))
978 (display-string (elpher-gemini-get-link-display-string line))
979 (address (elpher-address-from-gemini-url url)))
980 (if (> (length display-string) 0)
981 (elpher-insert-index-record display-string address)
982 (elpher-insert-index-record url address)))
983 (elpher-insert-index-record line)))
984 (elpher-cache-content
985 (elpher-node-address elpher-current-node)
988 (defun elpher-render-gemini-plain-text (data _parameters)
989 "Render DATA as plain text file. PARAMETERS is currently unused."
990 (elpher-with-clean-buffer
991 (insert (elpher-buttonify-urls data))
992 (elpher-cache-content
993 (elpher-node-address elpher-current-node)
996 ;; Other URL node opening
998 (defun elpher-get-other-url-node (renderer)
999 "Getter which attempts to open the URL specified by the current node (RENDERER must be nil)."
1001 (elpher-visit-parent-node)
1002 (error "Command not supported for general URLs"))
1003 (let* ((address (elpher-node-address elpher-current-node))
1004 (url (elpher-address-to-url address)))
1006 (elpher-visit-parent-node) ; Do first in case of non-local exits.
1007 (message "Opening URL...")
1008 (if elpher-open-urls-with-eww
1010 (browse-url url)))))
1012 ;; Telnet node connection
1014 (defun elpher-get-telnet-node (renderer)
1015 "Opens a telnet connection to the current node address (RENDERER must be nil)."
1017 (elpher-visit-parent-node)
1018 (error "Command not supported for telnet URLs"))
1019 (let* ((address (elpher-node-address elpher-current-node))
1020 (host (elpher-address-host address))
1021 (port (elpher-address-port address)))
1022 (elpher-visit-parent-node)
1027 ;; Start page node retrieval
1029 (defun elpher-get-start-node (renderer)
1030 "Getter which displays the start page (RENDERER must be nil)."
1032 (elpher-visit-parent-node)
1033 (error "Command not supported for start page"))
1034 (elpher-with-clean-buffer
1035 (insert " --------------------------------------------\n"
1036 " Elpher Gopher Client \n"
1037 " version " elpher-version "\n"
1038 " --------------------------------------------\n"
1040 "Default bindings:\n"
1042 " - TAB/Shift-TAB: next/prev item on current page\n"
1043 " - RET/mouse-1: open item under cursor\n"
1044 " - m: select an item on current page by name (autocompletes)\n"
1045 " - u/mouse-3: return to previous page\n"
1046 " - o/O: visit different selector or the root menu of the current server\n"
1047 " - g: go to a particular gopher address\n"
1048 " - d/D: download item under cursor or current page\n"
1049 " - i/I: info on item under cursor or current page\n"
1050 " - c/C: copy URL representation of item under cursor or current page\n"
1051 " - a/A: bookmark the item under cursor or current page\n"
1052 " - x/X: remove bookmark for item under cursor or current page\n"
1053 " - B: visit the bookmarks page\n"
1054 " - r: redraw current page (using cached contents if available)\n"
1055 " - R: reload current page (regenerates cache)\n"
1056 " - S: set character coding system for gopher (default is to autodetect)\n"
1057 " - T: toggle TLS gopher mode\n"
1058 " - .: display the raw server response for the current page\n"
1060 "Start your exploration of gopher space:\n")
1061 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1062 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1064 "Alternatively, select the following item and enter some search terms:\n")
1065 (elpher-insert-index-record "Veronica-2 Gopher Search Engine"
1066 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1068 "This page contains your bookmarked sites (also visit with B):\n")
1069 (elpher-insert-index-record "Your Bookmarks" 'bookmarks)
1072 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1073 (insert-text-button "Elpher info manual"
1079 'help-echo help-string))
1080 (insert " for the full documentation. **\n")
1082 (concat " (This should be available if you have installed Elpher using\n"
1083 " MELPA. Otherwise you will have to install the manual yourself.)")
1085 (elpher-restore-pos)))
1087 ;; Bookmarks page node retrieval
1089 (defun elpher-get-bookmarks-node (renderer)
1090 "Getter to load and display the current bookmark list (RENDERER must be nil)."
1092 (elpher-visit-parent-node)
1093 (error "Command not supported for bookmarks page"))
1094 (elpher-with-clean-buffer
1095 (insert "---- Bookmark list ----\n\n")
1096 (let ((bookmarks (elpher-load-bookmarks)))
1098 (dolist (bookmark bookmarks)
1099 (let ((display-string (elpher-bookmark-display-string bookmark))
1100 (address (elpher-address-from-url (elpher-bookmark-url bookmark))))
1101 (elpher-insert-index-record display-string address)))
1102 (insert "No bookmarks found.\n")))
1103 (insert "\n-----------------------\n\n"
1104 "- u: return to previous page\n"
1105 "- x: delete selected bookmark\n"
1106 "- a: rename selected bookmark\n\n"
1107 "Bookmarks are stored in the file "
1108 (locate-user-emacs-file "elpher-bookmarks"))
1109 (elpher-restore-pos)))
1115 (defun elpher-make-bookmark (display-string url)
1116 "Make an elpher bookmark.
1117 DISPLAY-STRING determines how the bookmark will appear in the
1118 bookmark list, while URL is the url of the entry."
1119 (list display-string url))
1121 (defun elpher-bookmark-display-string (bookmark)
1122 "Get the display string of BOOKMARK."
1125 (defun elpher-set-bookmark-display-string (bookmark display-string)
1126 "Set the display string of BOOKMARK to DISPLAY-STRING."
1127 (setcar bookmark display-string))
1129 (defun elpher-bookmark-url (bookmark)
1130 "Get the address for BOOKMARK."
1133 (defun elpher-save-bookmarks (bookmarks)
1134 "Record the bookmark list BOOKMARKS to the user's bookmark file.
1135 Beware that this completely replaces the existing contents of the file."
1136 (with-temp-file (locate-user-emacs-file "elpher-bookmarks")
1138 (insert "; Elpher bookmarks file\n\n"
1139 "; Bookmarks are stored as a list of (label URL) items.\n"
1140 "; Feel free to edit by hand, but take care to ensure\n"
1141 "; the list structure remains intact.\n\n")
1142 (pp bookmarks (current-buffer))))
1144 (defun elpher-load-bookmarks ()
1145 "Get the list of bookmarks from the users's bookmark file."
1149 (insert-file-contents (locate-user-emacs-file "elpher-bookmarks"))
1150 (goto-char (point-min))
1151 (read (current-buffer))))))
1152 (if (and bookmarks (listp (cadar bookmarks)))
1154 (message "Reading old bookmark file. (Will be updated on write.)")
1155 (mapcar (lambda (old-bm)
1157 (elpher-address-to-url (apply #'elpher-make-gopher-address
1162 (defun elpher-add-address-bookmark (address display-string)
1163 "Save a bookmark for ADDRESS with label DISPLAY-STRING.)))
1164 If ADDRESS is already bookmarked, update the label only."
1165 (let ((bookmarks (elpher-load-bookmarks))
1166 (url (elpher-address-to-url address)))
1167 (let ((existing-bookmark (rassoc (list url) bookmarks)))
1168 (if existing-bookmark
1169 (elpher-set-bookmark-display-string existing-bookmark display-string)
1170 (push (elpher-make-bookmark display-string url) bookmarks)))
1171 (elpher-save-bookmarks bookmarks)))
1173 (defun elpher-remove-address-bookmark (address)
1174 "Remove any bookmark to ADDRESS."
1175 (let ((url (elpher-address-to-url address)))
1176 (elpher-save-bookmarks
1177 (seq-filter (lambda (bookmark)
1178 (not (equal (elpher-bookmark-url bookmark) url)))
1179 (elpher-load-bookmarks)))))
1181 ;;; Interactive procedures
1184 (defun elpher-next-link ()
1185 "Move point to the next link on the current page."
1189 (defun elpher-prev-link ()
1190 "Move point to the previous link on the current page."
1192 (backward-button 1))
1194 (defun elpher-follow-current-link ()
1195 "Open the link or url at point."
1200 "Go to a particular gopher site read from the minibuffer."
1203 (let ((host-or-url (read-string "Gopher or Gemini URL: ")))
1204 (elpher-make-node host-or-url
1205 (elpher-address-from-url host-or-url)))))
1206 (switch-to-buffer "*elpher*")
1207 (elpher-visit-node node)))
1209 (defun elpher-go-current ()
1210 "Go to a particular site read from the minibuffer, initialized with the current URL."
1212 (let ((address (elpher-node-address elpher-current-node)))
1213 (if (elpher-address-special-p address)
1214 (error "Command invalid for this page")
1215 (let ((url (read-string "Gopher or Gemini URL: " (elpher-address-to-url address))))
1216 (elpher-visit-node (elpher-make-node url (elpher-address-from-url url)))))))
1218 (defun elpher-redraw ()
1219 "Redraw current page."
1221 (if elpher-current-node
1222 (elpher-visit-node elpher-current-node)
1223 (message "No current site.")))
1225 (defun elpher-reload ()
1226 "Reload current page."
1228 (if elpher-current-node
1229 (elpher-reload-current-node)
1230 (message "No current site.")))
1232 (defun elpher-toggle-tls ()
1233 "Toggle TLS encryption mode for gopher."
1235 (setq elpher-use-tls (not elpher-use-tls))
1237 (if (gnutls-available-p)
1238 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
1239 (setq elpher-use-tls nil)
1240 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
1241 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
1243 (defun elpher-view-raw ()
1244 "View raw server response for current page."
1246 (if elpher-current-node
1247 (if (elpher-address-special-p (elpher-node-address elpher-current-node))
1248 (error "This page was not generated by a server")
1249 (elpher-visit-node elpher-current-node
1250 #'elpher-render-raw))
1251 (message "No current site.")))
1253 (defun elpher-back ()
1254 "Go to previous site."
1256 (if (elpher-node-parent elpher-current-node)
1257 (elpher-visit-parent-node)
1258 (error "No previous site")))
1260 (defun elpher-download ()
1261 "Download the link at point."
1263 (let ((button (button-at (point))))
1265 (let ((node (button-get button 'elpher-node)))
1266 (if (elpher-address-special-p (elpher-node-address node))
1267 (error "Cannot download %s"
1268 (elpher-node-display-string node))
1269 (elpher-visit-node (button-get button 'elpher-node)
1270 #'elpher-render-download)))
1271 (error "No link selected"))))
1273 (defun elpher-download-current ()
1274 "Download the current page."
1276 (if (elpher-address-special-p (elpher-node-address elpher-current-node))
1277 (error "Cannot download %s"
1278 (elpher-node-display-string elpher-current-node))
1279 (elpher-visit-node (elpher-make-node
1280 (elpher-node-display-string elpher-current-node)
1281 (elpher-node-address elpher-current-node)
1282 elpher-current-node)
1283 #'elpher-render-download
1286 (defun elpher-build-link-map ()
1287 "Build alist mapping link names to destination nodes in current buffer."
1288 (let ((link-map nil)
1289 (b (next-button (point-min) t)))
1291 (push (cons (button-label b) b) link-map)
1292 (setq b (next-button (button-start b))))
1295 (defun elpher-jump ()
1296 "Select a directory entry by name. Similar to the info browser (m)enu command."
1298 (let* ((link-map (elpher-build-link-map)))
1300 (let ((key (let ((completion-ignore-case t))
1301 (completing-read "Directory item/link: "
1303 (if (and key (> (length key) 0))
1304 (let ((b (cdr (assoc key link-map))))
1305 (goto-char (button-start b))
1306 (button-activate b)))))))
1308 (defun elpher-root-dir ()
1309 "Visit root of current server."
1311 (let ((address (elpher-node-address elpher-current-node)))
1312 (if (not (elpher-address-special-p address))
1313 (if (or (member (url-filename address) '("/" ""))
1314 (and (elpher-address-gopher-p address)
1315 (= (length (elpher-gopher-address-selector address)) 0)))
1316 (error "Already at root directory of current server")
1317 (let ((address-copy (elpher-address-from-url
1318 (elpher-address-to-url address))))
1319 (setf (url-filename address-copy) "")
1321 (elpher-make-node (elpher-address-to-url address-copy)
1323 (error "Command invalid for %s" (elpher-node-display-string elpher-current-node)))))
1325 (defun elpher-bookmarks-current-p ()
1326 "Return non-nil if current node is a bookmarks page."
1327 (equal (elpher-address-type (elpher-node-address elpher-current-node))
1328 '(special bookmarks)))
1330 (defun elpher-reload-bookmarks ()
1331 "Reload bookmarks if current node is a bookmarks page."
1332 (if (elpher-bookmarks-current-p)
1333 (elpher-reload-current-node)))
1335 (defun elpher-bookmark-current ()
1336 "Bookmark the current node."
1338 (let ((address (elpher-node-address elpher-current-node))
1339 (display-string (elpher-node-display-string elpher-current-node)))
1340 (if (not (elpher-address-special-p address))
1341 (let ((bookmark-display-string (read-string "Bookmark display string: "
1343 (elpher-add-address-bookmark address bookmark-display-string)
1344 (message "Bookmark added."))
1345 (error "Cannot bookmark %s" display-string))))
1347 (defun elpher-bookmark-link ()
1348 "Bookmark the link at point."
1350 (let ((button (button-at (point))))
1352 (let* ((node (button-get button 'elpher-node))
1353 (address (elpher-node-address node))
1354 (display-string (elpher-node-display-string node)))
1355 (if (not (elpher-address-special-p address))
1356 (let ((bookmark-display-string (read-string "Bookmark display string: "
1358 (elpher-add-address-bookmark address bookmark-display-string)
1359 (elpher-reload-bookmarks)
1360 (message "Bookmark added."))
1361 (error "Cannot bookmark %s" display-string)))
1362 (error "No link selected"))))
1364 (defun elpher-unbookmark-current ()
1365 "Remove bookmark for the current node."
1367 (let ((address (elpher-node-address elpher-current-node)))
1368 (unless (elpher-address-special-p address)
1369 (elpher-remove-address-bookmark address)
1370 (message "Bookmark removed."))))
1372 (defun elpher-unbookmark-link ()
1373 "Remove bookmark for the link at point."
1375 (let ((button (button-at (point))))
1377 (let ((node (button-get button 'elpher-node)))
1378 (elpher-remove-address-bookmark (elpher-node-address node))
1379 (elpher-reload-bookmarks)
1380 (message "Bookmark removed."))
1381 (error "No link selected"))))
1383 (defun elpher-bookmarks ()
1384 "Visit bookmarks page."
1386 (switch-to-buffer "*elpher*")
1388 (elpher-make-node "Bookmarks Page" (elpher-make-special-address 'bookmarks))))
1390 (defun elpher-info-node (node)
1391 "Display information on NODE."
1392 (let ((display-string (elpher-node-display-string node))
1393 (address (elpher-node-address node)))
1394 (if (elpher-address-special-p address)
1395 (message "Special page: %s" display-string)
1396 (message "%s" (elpher-address-to-url address)))))
1398 (defun elpher-info-link ()
1399 "Display information on node corresponding to link at point."
1401 (let ((button (button-at (point))))
1403 (elpher-info-node (button-get button 'elpher-node))
1404 (error "No item selected"))))
1406 (defun elpher-info-current ()
1407 "Display information on current node."
1409 (elpher-info-node elpher-current-node))
1411 (defun elpher-copy-node-url (node)
1412 "Copy URL representation of address of NODE to `kill-ring'."
1413 (let ((address (elpher-node-address node)))
1414 (if (elpher-address-special-p address)
1415 (error (format "Cannot represent %s as URL" (elpher-node-display-string node)))
1416 (let ((url (elpher-address-to-url address)))
1417 (message "Copied \"%s\" to kill-ring/clipboard." url)
1420 (defun elpher-copy-link-url ()
1421 "Copy URL of item at point to `kill-ring'."
1423 (let ((button (button-at (point))))
1425 (elpher-copy-node-url (button-get button 'elpher-node))
1426 (error "No item selected"))))
1428 (defun elpher-copy-current-url ()
1429 "Copy URL of current node to `kill-ring'."
1431 (elpher-copy-node-url elpher-current-node))
1433 (defun elpher-set-gopher-coding-system ()
1434 "Specify an explicit character coding system for gopher selectors."
1436 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
1437 (setq elpher-user-coding-system system)
1439 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
1440 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
1446 (defvar elpher-mode-map
1447 (let ((map (make-sparse-keymap)))
1448 (define-key map (kbd "TAB") 'elpher-next-link)
1449 (define-key map (kbd "<backtab>") 'elpher-prev-link)
1450 (define-key map (kbd "u") 'elpher-back)
1451 (define-key map [mouse-3] 'elpher-back)
1452 (define-key map (kbd "O") 'elpher-root-dir)
1453 (define-key map (kbd "g") 'elpher-go)
1454 (define-key map (kbd "o") 'elpher-go-current)
1455 (define-key map (kbd "r") 'elpher-redraw)
1456 (define-key map (kbd "R") 'elpher-reload)
1457 (define-key map (kbd "T") 'elpher-toggle-tls)
1458 (define-key map (kbd ".") 'elpher-view-raw)
1459 (define-key map (kbd "d") 'elpher-download)
1460 (define-key map (kbd "D") 'elpher-download-current)
1461 (define-key map (kbd "m") 'elpher-jump)
1462 (define-key map (kbd "i") 'elpher-info-link)
1463 (define-key map (kbd "I") 'elpher-info-current)
1464 (define-key map (kbd "c") 'elpher-copy-link-url)
1465 (define-key map (kbd "C") 'elpher-copy-current-url)
1466 (define-key map (kbd "a") 'elpher-bookmark-link)
1467 (define-key map (kbd "A") 'elpher-bookmark-current)
1468 (define-key map (kbd "x") 'elpher-unbookmark-link)
1469 (define-key map (kbd "X") 'elpher-unbookmark-current)
1470 (define-key map (kbd "B") 'elpher-bookmarks)
1471 (define-key map (kbd "S") 'elpher-set-gopher-coding-system)
1472 (when (fboundp 'evil-define-key*)
1473 (evil-define-key* 'motion map
1474 (kbd "TAB") 'elpher-next-link
1475 (kbd "C-") 'elpher-follow-current-link
1476 (kbd "C-t") 'elpher-back
1477 (kbd "u") 'elpher-back
1478 [mouse-3] 'elpher-back
1479 (kbd "g") 'elpher-go
1480 (kbd "o") 'elpher-go-current
1481 (kbd "r") 'elpher-redraw
1482 (kbd "R") 'elpher-reload
1483 (kbd "T") 'elpher-toggle-tls
1484 (kbd ".") 'elpher-view-raw
1485 (kbd "d") 'elpher-download
1486 (kbd "D") 'elpher-download-current
1487 (kbd "m") 'elpher-jump
1488 (kbd "i") 'elpher-info-link
1489 (kbd "I") 'elpher-info-current
1490 (kbd "c") 'elpher-copy-link-url
1491 (kbd "C") 'elpher-copy-current-url
1492 (kbd "a") 'elpher-bookmark-link
1493 (kbd "A") 'elpher-bookmark-current
1494 (kbd "x") 'elpher-unbookmark-link
1495 (kbd "X") 'elpher-unbookmark-current
1496 (kbd "B") 'elpher-bookmarks
1497 (kbd "S") 'elpher-set-gopher-coding-system))
1499 "Keymap for gopher client.")
1501 (define-derived-mode elpher-mode special-mode "elpher"
1502 "Major mode for elpher, an elisp gopher client.
1504 This mode is automatically enabled by the interactive
1505 functions which initialize the gopher client, namely
1506 `elpher', `elpher-go' and `elpher-bookmarks'.")
1508 (when (fboundp 'evil-set-initial-state)
1509 (evil-set-initial-state 'elpher-mode 'motion))
1512 ;;; Main start procedure
1517 "Start elpher with default landing page."
1519 (if (get-buffer "*elpher*")
1520 (switch-to-buffer "*elpher*")
1521 (switch-to-buffer "*elpher*")
1522 (setq elpher-current-node nil)
1523 (let ((start-node (elpher-make-node "Elpher Start Page"
1524 (elpher-make-special-address 'start))))
1525 (elpher-visit-node start-node)))
1526 "Started Elpher.") ; Otherwise (elpher) evaluates to start page string.
1528 ;;; elpher.el ends here