1 ;;; elpher.el --- A friendly gopher client.
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.
41 ;; To launch Elpher, simply use 'M-x elpher'. This will open a start
42 ;; page containing information on key bindings and suggested starting
43 ;; points for your gopher exploration.
45 ;; Full instructions can be found in the Elpher info manual.
47 ;; Elpher is under active development. Any suggestions for
48 ;; improvements are welcome!
66 (defconst elpher-version "1.4.7"
67 "Current version of elpher.")
69 (defconst elpher-margin-width 6
70 "Width of left-hand margin used when rendering indicies.")
72 (defconst elpher-transport-map
73 '(("gopher" elpher-get-gopher-selector)
74 ("gophers" elpher-get-gopher-selector)
75 ("gemini" elpher-get-gemini-selector)))
77 (defconst elpher-gopher-type-map
78 '((?0 elpher-display-text "txt" elpher-text)
79 (?1 elpher-display-gophermap "/" elpher-index)
80 (?4 nil "bin" elpher-binary)
81 (?5 nil "bin" elpher-binary)
82 (?7 elpher-display-search-node "?" elpher-search)
83 (?8 elpher-display-telnet-node "tel" elpher-telnet)
84 (?9 nil "bin" elpher-binary)
85 (?g elpher-display-image-node "img" elpher-image)
86 (?p elpher-display-image-node "img" elpher-image)
87 (?I elpher-display-image-node "img" elpher-image)
88 (?d nil "doc" elpher-binary)
89 (?P nil "doc" elpher-binary)
90 (?s nil "snd" elpher-binary)
91 (?h elpher-display-node-html "htm" elpher-html))
92 "Association list from types to getters, margin codes and index faces.")
94 (defconst elpher-mime-type-map
95 '(("text/gemini" elpher-display-node-text)
96 ("text/html" elpher-display-node-html)
97 ("text/*" elpher-display-node-text)
98 ("image/*" elpher-display-image-node)))
100 ;;; Customization group
105 :group 'applications)
107 ;; Face customizations
109 (defface elpher-index
110 '((t :inherit font-lock-keyword-face))
111 "Face used for directory type directory records.")
115 "Face used for text type directory records.")
118 '((t :inherit default))
119 "Face used for info type directory records.")
121 (defface elpher-image
122 '((t :inherit font-lock-string-face))
123 "Face used for image type directory records.")
125 (defface elpher-search
126 '((t :inherit warning))
127 "Face used for search type directory records.")
130 '((t :inherit font-lock-comment-face))
131 "Face used for url type directory records.")
133 (defface elpher-telnet
134 '((t :inherit font-lock-function-name-face))
135 "Face used for telnet type directory records.")
137 (defface elpher-binary
138 '((t :inherit font-lock-doc-face))
139 "Face used for binary type directory records.")
141 (defface elpher-unknown
142 '((t :inherit error))
143 "Face used for directory records with unknown/unsupported types.")
145 (defface elpher-margin-key
147 "Face used for directory margin key.")
149 (defface elpher-margin-brackets
150 '((t :inherit shadow))
151 "Face used for brackets around directory margin key.")
153 ;; Other customizations
155 (defcustom elpher-open-urls-with-eww nil
156 "If non-nil, open URL selectors using eww.
157 Otherwise, use the system browser via the BROWSE-URL function."
160 (defcustom elpher-buttonify-urls-in-directories nil
161 "If non-nil, turns URLs matched in directories into clickable buttons."
164 (defcustom elpher-use-header t
165 "If non-nil, display current node information in buffer header."
168 (defcustom elpher-auto-disengage-TLS nil
169 "If non-nil, automatically disengage TLS following an unsuccessful connection.
170 While enabling this may seem convenient, it is also potentially dangerous as it
171 allows switching from an encrypted channel back to plain text without user input."
180 (defun elpher-url-from-string (url-string)
181 "Create a URL object corresponding to the given URL-STRING."
182 (let ((url (url-generic-parse-url url-string)))
183 (if (and (url-type url)
185 (setf (url-filename url) (url-unhex-string (url-filename url)))
186 (error "Malformed URL" url))))
188 (defun elpher-url-to-url-string (url)
189 "Get string representation of URL."
190 (url-encode-url (url-recreate url)))
192 (defun elpher-url-gopher-p (url)
193 "Return non-nil if URL object specifies a gopher address."
194 (let ((protocol (url-type url)))
195 (if (or (string-equal protocol "gopher")
196 (string-equal protocol "gophers")))))
198 (defun elpher-gopher-url-selector-type (url)
199 "Retrieve selector type from URL object."
200 (let ((filename (url-filename url)))
201 (if (> (length filename) 0)
202 (string-to-char filename)
205 (defun elpher-gopher-url-selector (url)
206 "Retrieve selector from URL object."
207 (let ((filename (url-filename url)))
208 (if (> (length filename) 0)
209 (substring filename 1)
212 (defun elpher-url-host (url)
213 "Retrieve host from URL object."
216 (defun elpher-url-port (url)
217 "Retrieve port from URL object."
220 (defun elpher-url-use-tls-p (url)
221 "Return non-nil if URL is marked as needing TLS."
222 (string-equal (url-type address) "gophers"))
224 (defun elpher-url-special-p (url)
225 "Return non-nil if URL object is special (e.g. start page, bookmarks page)."
230 (defun elpher-make-node (display-string url &optional parent)
231 "Create a node in the page hierarchy.
233 DISPLAY-STRING records the display string used for the page.
235 URL specifies the url object of the page.
237 The optional PARENT specifies the parent node in the hierarchy.
238 This is set every time the node is visited, so while it forms
239 an important part of the node data there is no need to set it
241 (list display-string url parent))
243 (defun elpher-node-display-string (node)
244 "Retrieve the display string of NODE."
247 (defun elpher-node-url (node)
248 "Retrieve the URL object of NODE."
251 (defun elpher-node-parent (node)
252 "Retrieve the parent node of NODE."
255 (defun elpher-set-node-parent (node parent)
256 "Set the parent node of NODE to be PARENT."
257 (setcar (cdr (cdr node)) parent))
261 (defvar elpher-content-cache (make-hash-table :test 'equal))
262 (defvar elpher-pos-cache (make-hash-table :test 'equal))
264 (defun elpher-get-cached-content (url)
265 "Retrieve the cached content for URL, or nil if none exists."
266 (gethash url elpher-content-cache))
268 (defun elpher-cache-content (url content)
269 "Set the content cache for URL to CONTENT."
270 (puthash url content elpher-content-cache))
272 (defun elpher-get-cached-pos (url)
273 "Retrieve the cached cursor position for URL, or nil if none exists."
274 (gethash url elpher-pos-cache))
276 (defun elpher-cache-pos (url pos)
277 "Set the cursor position cache for URL to POS."
278 (puthash url pos elpher-pos-cache))
280 ;; Node graph traversal
282 (defvar elpher-current-node nil)
284 (defun elpher-visit-node (node &optional getter preserve-parent)
285 "Visit NODE using its own getter or GETTER, if non-nil.
286 Additionally, set the parent of NODE to `elpher-current-node',
287 unless PRESERVE-PARENT is non-nil."
289 (elpher-process-cleanup)
290 (unless preserve-parent
291 (if (and (elpher-node-parent elpher-current-node)
292 (equal (elpher-node-url elpher-current-node)
293 (elpher-node-url node)))
294 (elpher-set-node-parent node (elpher-node-parent elpher-current-node))
295 (elpher-set-node-parent node elpher-current-node)))
296 (setq elpher-current-node node)
299 ;; The business below needs updating: mapping from url->getter is different
301 (let* ((url (elpher-node-url node))
302 (type (elpher-address-type address))
303 (type-record (alist-get type elpher-type-map)))
305 (funcall (car type-record))
306 (elpher-visit-parent-node)
307 (error "Unsupported gopher selector type '%c'" type)))))
309 (defun elpher-visit-parent-node ()
310 "Visit the parent of the current node."
311 (let ((parent-node (elpher-node-parent elpher-current-node)))
313 (elpher-visit-node parent-node nil t))))
315 (defun elpher-reload-current-node ()
316 "Reload the current node, discarding any existing cached content."
317 (elpher-cache-content (elpher-node-address elpher-current-node) nil)
318 (elpher-visit-node elpher-current-node))
320 (defun elpher-save-pos ()
321 "Save the current position of point to the current node."
322 (when elpher-current-node
323 (elpher-cache-pos (elpher-node-address elpher-current-node) (point))))
325 (defun elpher-restore-pos ()
326 "Restore the position of point to that cached in the current node."
327 (let ((pos (elpher-get-cached-pos (elpher-node-address elpher-current-node))))
330 (goto-char (point-min)))))
333 ;;; Buffer preparation
336 (defun elpher-update-header ()
337 "If `elpher-use-header' is true, display current node info in window header."
338 (if elpher-use-header
339 (setq header-line-format (elpher-node-display-string elpher-current-node))))
341 (defmacro elpher-with-clean-buffer (&rest args)
342 "Evaluate ARGS with a clean *elpher* buffer as current."
343 (list 'with-current-buffer "*elpher*"
345 (append (list 'let '((inhibit-read-only t))
347 '(elpher-update-header))
354 (defvar elpher-user-coding-system nil
355 "User-specified coding system to use for decoding text responses.")
357 (defun elpher-decode (string)
358 "Decode STRING using autodetected or user-specified coding system."
359 (decode-coding-string string
360 (if elpher-user-coding-system
361 elpher-user-coding-system
362 (detect-coding-string string t))))
364 (defun elpher-preprocess-text-response (string)
365 "Preprocess text selector response contained in STRING.
366 This involes decoding the character representation, and clearing
367 away CRs and any terminating period."
368 (elpher-decode (replace-regexp-in-string "\n\.\n$" "\n"
369 (replace-regexp-in-string "\r" "" string))))
374 (defun elpher-insert-index (string)
375 "Insert the index corresponding to STRING into the current buffer."
376 ;; Should be able to split directly on CRLF, but some non-conformant
377 ;; LF-only servers sadly exist, hence the following.
378 (let ((str-processed (elpher-preprocess-text-response string)))
379 (dolist (line (split-string str-processed "\n"))
380 (unless (= (length line) 0)
381 (let* ((type (elt line 0))
382 (fields (split-string (substring line 1) "\t"))
383 (display-string (elt fields 0))
384 (selector (elt fields 1))
385 (host (elt fields 2))
386 (port (if (elt fields 3)
387 (string-to-number (elt fields 3))
389 (address (elpher-make-address type selector host port)))
390 (elpher-insert-index-record display-string address))))))
392 (defun elpher-insert-margin (&optional type-name)
393 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
396 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
398 (propertize "[" 'face 'elpher-margin-brackets)
399 (propertize type-name 'face 'elpher-margin-key)
400 (propertize "]" 'face 'elpher-margin-brackets))))
402 (insert (make-string elpher-margin-width ?\s))))
404 (defun elpher-node-button-help (node)
405 "Return a string containing the help text for a button corresponding to NODE."
406 (let ((address (elpher-node-address node)))
407 (if (eq (elpher-address-type address) ?h)
408 (let ((url (cadr (split-string (elpher-address-selector address) "URL:"))))
409 (format "mouse-1, RET: open url '%s'" url))
410 (format "mouse-1, RET: open '%s' on %s port %s"
411 (elpher-address-selector address)
412 (elpher-address-host address)
413 (elpher-address-port address)))))
416 (defun elpher-insert-index-record (display-string address)
417 "Function to insert an index record into the current buffer.
418 The contents of the record are dictated by DISPLAY-STRING and ADDRESS."
419 (let* ((type (elpher-address-type address))
420 (type-map-entry (alist-get type elpher-type-map)))
422 (let* ((margin-code (elt type-map-entry 1))
423 (face (elt type-map-entry 2))
424 (node (elpher-make-node display-string address)))
425 (elpher-insert-margin margin-code)
426 (insert-text-button display-string
429 'action #'elpher-click-link
431 'help-echo (elpher-node-button-help node)))
434 (elpher-insert-margin)
436 (if elpher-buttonify-urls-in-directories
437 (elpher-buttonify-urls display-string)
439 'face 'elpher-info)))
441 (elpher-insert-margin (concat (char-to-string type) "?"))
442 (insert (propertize display-string
443 'face 'elpher-unknown)))))
446 (defun elpher-click-link (button)
447 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
448 (let ((node (button-get button 'elpher-node)))
449 (elpher-visit-node node)))
452 ;;; Selector retrieval (all kinds)
455 (defun elpher-process-cleanup ()
456 "Immediately shut down any extant elpher process."
457 (let ((p (get-process "elpher-process")))
458 (if p (delete-process p))))
460 (defvar elpher-use-tls nil
461 "If non-nil, use TLS to communicate with gopher servers.")
463 (defvar elpher-selector-string)
465 (defun elpher-get-selector (address after &optional propagate-error)
466 "Retrieve selector specified by ADDRESS, then execute AFTER.
467 The result is stored as a string in the variable ‘elpher-selector-string’.
469 Usually errors result in an error page being displayed. This is only
470 appropriate if the selector is to be directly viewed. If PROPAGATE-ERROR
471 is non-nil, this message is not displayed. Instead, the error propagates
472 up to the calling function."
473 (setq elpher-selector-string "")
474 (when (elpher-address-use-tls-p address)
475 (if (gnutls-available-p)
476 (when (not elpher-use-tls)
477 (setq elpher-use-tls t)
478 (message "Engaging TLS mode."))
479 (error "Cannot retrieve TLS selector: GnuTLS not available")))
480 (condition-case the-error
481 (let* ((kill-buffer-query-functions nil)
482 (proc (open-network-stream "elpher-process"
484 (elpher-address-host address)
485 (elpher-address-port address)
486 :type (if elpher-use-tls 'tls 'plain))))
487 (set-process-coding-system proc 'binary)
488 (set-process-filter proc
489 (lambda (proc string)
490 (setq elpher-selector-string
491 (concat elpher-selector-string string))))
492 (set-process-sentinel proc after)
493 (process-send-string proc
494 (concat (elpher-address-selector address) "\n")))
496 (if (and (consp the-error)
497 (eq (car the-error) 'gnutls-error)
498 (not (elpher-address-use-tls-p address))
499 (or elpher-auto-disengage-TLS
500 (yes-or-no-p "Could not establish encrypted connection. Disable TLS mode? ")))
502 (message "Disengaging TLS mode.")
503 (setq elpher-use-tls nil)
504 (elpher-get-selector address after))
505 (elpher-process-cleanup)
508 (elpher-with-clean-buffer
509 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
510 "Failed to connect to " (elpher-get-address-url address) ".\n"
511 (propertize "\n----------------\n\n" 'face 'error)
512 "Press 'u' to return to the previous page.")))))))
516 (defun elpher-get-index-node ()
517 "Getter which retrieves the current node contents as an index."
518 (let* ((address (elpher-node-address elpher-current-node))
519 (content (elpher-get-cached-content address)))
522 (elpher-with-clean-buffer
524 (elpher-restore-pos)))
525 (elpher-with-clean-buffer
526 (insert "LOADING DIRECTORY... (use 'u' to cancel)"))
527 (elpher-get-selector address
529 (unless (string-prefix-p "deleted" event)
530 (elpher-with-clean-buffer
531 (elpher-insert-index elpher-selector-string)
533 (elpher-cache-content
534 (elpher-node-address elpher-current-node)
535 (buffer-string)))))))))
539 (defconst elpher-url-regex
540 "\\([a-zA-Z]+\\)://\\([a-zA-Z0-9.\-]+\\|\[[a-zA-Z0-9:]+\]\\)\\(?3::[0-9]+\\)?\\(?4:/[^ \r\n\t(),]*\\)?"
541 "Regexp used to locate and buttinofy URLs in text files loaded by elpher.")
543 (defun elpher-make-node-from-matched-url (&optional string)
544 "Convert most recent `elpher-url-regex' match to a node.
546 If STRING is non-nil, this is given as an argument to all `match-string'
547 calls, as is necessary if the match is performed by `string-match'."
548 (let ((url (match-string 0 string))
549 (protocol (downcase (match-string 1 string))))
550 (if (or (string= protocol "gopher")
551 (string= protocol "gophers"))
552 (let* ((bare-host (match-string 2 string))
553 (host (if (string-prefix-p "[" bare-host)
554 (substring bare-host 1 (- (length bare-host) 1))
556 (port (if (> (length (match-string 3 string)) 1)
557 (string-to-number (substring (match-string 3 string) 1))
559 (type-and-selector (match-string 4 string))
560 (type (if (> (length type-and-selector) 1)
561 (elt type-and-selector 1)
563 (selector (decode-coding-string
565 (if (> (length type-and-selector) 1)
566 (substring type-and-selector 2)
568 (use-tls (string= protocol "gophers"))
569 (address (elpher-make-address type selector host port use-tls)))
570 (elpher-make-node url address))
571 (let* ((host (match-string 2 string))
572 (port (if (> (length (match-string 3 string)) 1)
573 (string-to-number (substring (match-string 3 string) 1))
575 (selector (concat "URL:" url))
576 (address (elpher-make-address ?h selector host port)))
577 (elpher-make-node url address)))))
580 (defun elpher-buttonify-urls (string)
581 "Turn substrings which look like urls in STRING into clickable buttons."
584 (goto-char (point-min))
585 (while (re-search-forward elpher-url-regex nil t)
586 (let ((node (elpher-make-node-from-matched-url)))
587 (make-text-button (match-beginning 0)
590 'action #'elpher-click-link
592 'help-echo (elpher-node-button-help node))))
595 (defun elpher-get-text-node ()
596 "Getter which retrieves the current node contents as a text document."
597 (let* ((address (elpher-node-address elpher-current-node))
598 (content (elpher-get-cached-content address)))
601 (elpher-with-clean-buffer
603 (elpher-restore-pos)))
605 (elpher-with-clean-buffer
606 (insert "LOADING TEXT... (use 'u' to cancel)"))
607 (elpher-get-selector address
609 (unless (string-prefix-p "deleted" event)
610 (elpher-with-clean-buffer
611 (insert (elpher-buttonify-urls
612 (elpher-preprocess-text-response
613 elpher-selector-string)))
615 (elpher-cache-content
616 (elpher-node-address elpher-current-node)
617 (buffer-string))))))))))
621 (defun elpher-get-image-node ()
622 "Getter which retrieves the current node contents as an image to view."
623 (let* ((address (elpher-node-address elpher-current-node)))
624 (if (display-images-p)
626 (elpher-with-clean-buffer
627 (insert "LOADING IMAGE... (use 'u' to cancel)"))
628 (elpher-get-selector address
630 (unless (string-prefix-p "deleted" event)
631 (let ((image (create-image
632 elpher-selector-string
634 (elpher-with-clean-buffer
636 (elpher-restore-pos)))))))
637 (elpher-get-node-download))))
641 (defun elpher-get-search-node ()
642 "Getter which submits a search query to the address of the current node."
643 (let* ((address (elpher-node-address elpher-current-node))
644 (content (elpher-get-cached-content address))
648 (elpher-with-clean-buffer
650 (elpher-restore-pos))
651 (message "Displaying cached search results. Reload to perform a new search."))
653 (let* ((query-string (read-string "Query: "))
654 (query-selector (concat (elpher-address-selector address) "\t" query-string))
655 (search-address (elpher-make-address ?1
657 (elpher-address-host address)
658 (elpher-address-port address))))
660 (elpher-with-clean-buffer
661 (insert "LOADING RESULTS... (use 'u' to cancel)"))
662 (elpher-get-selector search-address
664 (unless (string-prefix-p "deleted" event)
665 (elpher-with-clean-buffer
666 (elpher-insert-index elpher-selector-string))
667 (goto-char (point-min))
668 (elpher-cache-content
669 (elpher-node-address elpher-current-node)
672 (elpher-visit-parent-node))))))
674 ;; Raw server response retrieval
676 (defun elpher-get-node-raw ()
677 "Getter which retrieves the raw server response for the current node."
678 (let ((address (elpher-node-address elpher-current-node)))
679 (elpher-with-clean-buffer
680 (insert "LOADING RAW SERVER RESPONSE... (use 'u' to cancel)"))
681 (elpher-get-selector address
683 (unless (string-prefix-p "deleted" event)
684 (elpher-with-clean-buffer
685 (insert elpher-selector-string)
686 (goto-char (point-min)))))))
687 (message "Displaying raw server response. Reload or redraw to return to standard view."))
689 ;; File export retrieval
691 (defvar elpher-download-filename)
693 (defun elpher-get-node-download ()
694 "Getter which retrieves the current node and writes the result to a file."
695 (let* ((address (elpher-node-address elpher-current-node))
696 (selector (elpher-address-selector address)))
697 (elpher-visit-parent-node) ; Do first in case of non-local exits.
698 (let* ((filename-proposal (file-name-nondirectory selector))
699 (filename (read-file-name "Save file as: "
701 (if (> (length filename-proposal) 0)
704 (message "Downloading...")
705 (setq elpher-download-filename filename)
706 (condition-case the-error
707 (elpher-get-selector address
709 (let ((coding-system-for-write 'binary))
710 (with-temp-file elpher-download-filename
711 (insert elpher-selector-string)
712 (message (format "Download complate, saved to file %s."
713 elpher-download-filename)))))
716 (error "Error downloading %s" elpher-download-filename))))))
720 (defun elpher-insert-rendered-html (string)
721 "Use shr to insert rendered view of html STRING into current buffer."
722 (let ((dom (with-temp-buffer
724 (libxml-parse-html-region (point-min) (point-max)))))
725 (shr-insert-document dom)))
727 (defun elpher-get-url-node ()
728 "Getter which attempts to open the URL specified by the current node."
729 (let* ((address (elpher-node-address elpher-current-node))
730 (selector (elpher-address-selector address)))
731 (let ((url (elt (split-string selector "URL:") 1)))
734 (elpher-visit-parent-node) ; Do first in case of non-local exits.
735 (message "Opening URL...")
736 (if elpher-open-urls-with-eww
739 (let ((content (elpher-get-cached-content address)))
742 (elpher-with-clean-buffer
744 (elpher-restore-pos)))
745 (elpher-with-clean-buffer
746 (insert "LOADING HTML... (use 'u' to cancel)"))
747 (elpher-get-selector address
749 (unless (string-prefix-p "deleted" event)
750 (elpher-with-clean-buffer
751 (elpher-insert-rendered-html elpher-selector-string)
752 (goto-char (point-min))
753 (elpher-cache-content
754 (elpher-node-address elpher-current-node)
755 (buffer-string))))))))))))
757 ;; Telnet node connection
759 (defun elpher-get-telnet-node ()
760 "Getter which opens a telnet connection to the server specified by the current node."
761 (let* ((address (elpher-node-address elpher-current-node))
762 (host (elpher-address-host address))
763 (port (elpher-address-port address)))
764 (elpher-visit-parent-node)
767 ;; Start page node retrieval
769 (defun elpher-get-start-node ()
770 "Getter which displays the start page."
771 (elpher-with-clean-buffer
772 (insert " --------------------------------------------\n"
773 " Elpher Gopher Client \n"
774 " version " elpher-version "\n"
775 " --------------------------------------------\n"
777 "Default bindings:\n"
779 " - TAB/Shift-TAB: next/prev item on current page\n"
780 " - RET/mouse-1: open item under cursor\n"
781 " - m: select an item on current page by name (autocompletes)\n"
782 " - u: return to previous page\n"
783 " - o/O: visit different selector or the root menu of the current server\n"
784 " - g: go to a particular gopher address\n"
785 " - i/I: info on item under cursor or current page\n"
786 " - c/C: copy URL representation of item under cursor or current page\n"
787 " - a/A: bookmark the item under cursor or current page\n"
788 " - x/X: remove bookmark for item under cursor or current page\n"
789 " - B: visit the bookmarks page\n"
790 " - r: redraw current page (using cached contents if available)\n"
791 " - R: reload current page (regenerates cache)\n"
792 " - T: toggle TLS mode\n"
793 " - d/D: download item under cursor or current page\n"
794 " - .: display the raw server response for the current page\n"
795 " - S: set an explicit character coding system (default is to autodetect)\n"
797 "Start your exploration of gopher space:\n")
798 (elpher-insert-index-record "Floodgap Systems Gopher Server"
799 (elpher-make-address ?1 "" "gopher.floodgap.com" 70))
801 "Alternatively, select the following item and enter some search terms:\n")
802 (elpher-insert-index-record "Veronica-2 Gopher Search Engine"
803 (elpher-make-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
806 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
807 (insert-text-button "Elpher info manual"
809 'action (lambda (button)
813 'help-echo help-string))
814 (insert " for the full documentation. **\n")
816 (concat " (This should be available if you have installed Elpher using\n"
817 " MELPA. Otherwise you will have to install the manual yourself.)")
819 (elpher-restore-pos)))
821 ;; Bookmarks page node retrieval
823 (defun elpher-get-bookmarks-node ()
824 "Getter to load and display the current bookmark list."
825 (elpher-with-clean-buffer
826 (insert "---- Bookmark list ----\n\n")
827 (let ((bookmarks (elpher-load-bookmarks)))
829 (dolist (bookmark bookmarks)
830 (let ((display-string (elpher-bookmark-display-string bookmark))
831 (address (elpher-bookmark-address bookmark)))
832 (elpher-insert-index-record display-string address)))
833 (insert "No bookmarks found.\n")))
834 (insert "\n-----------------------\n\n"
835 "- u: return to previous page\n"
836 "- x: delete selected bookmark\n"
837 "- a: rename selected bookmark\n\n"
838 "Bookmarks are stored in the file "
839 (locate-user-emacs-file "elpher-bookmarks"))
840 (elpher-restore-pos)))
846 (defun elpher-make-bookmark (display-string address)
847 "Make an elpher bookmark.
848 DISPLAY-STRING determines how the bookmark will appear in the
849 bookmark list, while ADDRESS is the address of the entry."
850 (list display-string address))
852 (defun elpher-bookmark-display-string (bookmark)
853 "Get the display string of BOOKMARK."
856 (defun elpher-set-bookmark-display-string (bookmark display-string)
857 "Set the display string of BOOKMARK to DISPLAY-STRING."
858 (setcar bookmark display-string))
860 (defun elpher-bookmark-address (bookmark)
861 "Get the address for BOOKMARK."
864 (defun elpher-save-bookmarks (bookmarks)
865 "Record the bookmark list BOOKMARKS to the user's bookmark file.
866 Beware that this completely replaces the existing contents of the file."
867 (with-temp-file (locate-user-emacs-file "elpher-bookmarks")
869 (insert "; Elpher gopher bookmarks file\n\n"
870 "; Bookmarks are stored as a list of (label (type selector host port))\n"
871 "; s-expressions, where type is stored as a character (i.e. 49 = ?1).\n"
872 "; Feel free to edit by hand, but ensure this structure remains intact.\n\n")
873 (pp bookmarks (current-buffer))))
875 (defun elpher-load-bookmarks ()
876 "Get the list of bookmarks from the users's bookmark file."
879 (insert-file-contents (locate-user-emacs-file "elpher-bookmarks"))
880 (goto-char (point-min))
881 (read (current-buffer)))))
883 (defun elpher-add-address-bookmark (address display-string)
884 "Save a bookmark for ADDRESS with label DISPLAY-STRING.
885 If ADDRESS is already bookmarked, update the label only."
886 (let ((bookmarks (elpher-load-bookmarks)))
887 (let ((existing-bookmark (rassoc (list address) bookmarks)))
888 (if existing-bookmark
889 (elpher-set-bookmark-display-string existing-bookmark display-string)
890 (add-to-list 'bookmarks (elpher-make-bookmark display-string address))))
891 (elpher-save-bookmarks bookmarks)))
893 (defun elpher-remove-address-bookmark (address)
894 "Remove any bookmark to ADDRESS."
895 (elpher-save-bookmarks
896 (seq-filter (lambda (bookmark)
897 (not (equal (elpher-bookmark-address bookmark) address)))
898 (elpher-load-bookmarks))))
901 ;;; Interactive procedures
904 (defun elpher-next-link ()
905 "Move point to the next link on the current page."
909 (defun elpher-prev-link ()
910 "Move point to the previous link on the current page."
914 (defun elpher-follow-current-link ()
915 "Open the link or url at point."
920 "Go to a particular gopher site read from the minibuffer.
921 The site may be specified via a URL or explicitly in terms of
922 host, selector and port."
925 (let ((host-or-url (read-string "Gopher host or URL: ")))
926 (if (string-match elpher-url-regex host-or-url)
927 (elpher-make-node-from-matched-url host-or-url)
928 (let ((selector (read-string "Selector (default none): " nil nil ""))
929 (port-string (read-string "Port (default 70): " nil nil "70")))
930 (elpher-make-node (concat "gopher://" host-or-url
933 (elpher-make-address ?1 selector host-or-url
934 (string-to-number port-string))))))))
935 (switch-to-buffer "*elpher*")
936 (elpher-visit-node node)))
938 (defun elpher-go-current ()
939 "Go to a particular site read from the minibuffer, initialized with the current URL."
941 (let ((address (elpher-node-address elpher-current-node)))
942 (if (elpher-address-special-p address)
943 (error "Command not valid for this page")
944 (let ((url (read-string "URL: " (elpher-get-address-url address))))
945 (if (string-match elpher-url-regex url)
946 (let ((new-node (elpher-make-node-from-matched-url url)))
947 (unless (equal (elpher-node-address new-node) address)
948 (elpher-visit-node new-node)))
949 (error "Could not parse URL %s" url))))))
951 (defun elpher-redraw ()
952 "Redraw current page."
954 (if elpher-current-node
955 (elpher-visit-node elpher-current-node)
956 (message "No current site.")))
958 (defun elpher-reload ()
959 "Reload current page."
961 (if elpher-current-node
962 (elpher-reload-current-node)
963 (message "No current site.")))
965 (defun elpher-toggle-tls ()
966 "Toggle TLS encryption mode."
968 (setq elpher-use-tls (not elpher-use-tls))
970 (if (gnutls-available-p)
971 (message "TLS mode enabled. (Will not affect current page until reload.)")
972 (setq elpher-use-tls nil)
973 (error "Cannot enable TLS mode: GnuTLS not available"))
974 (message "TLS mode disabled. (Will not affect current page until reload.)")))
976 (defun elpher-view-raw ()
977 "View raw server response for current page."
979 (if elpher-current-node
980 (if (elpher-address-special-p (elpher-node-address elpher-current-node))
981 (error "This page was not generated by a server")
982 (elpher-visit-node elpher-current-node
983 #'elpher-get-node-raw))
984 (message "No current site.")))
986 (defun elpher-back ()
987 "Go to previous site."
989 (if (elpher-node-parent elpher-current-node)
990 (elpher-visit-parent-node)
991 (error "No previous site")))
993 (defun elpher-download ()
994 "Download the link at point."
996 (let ((button (button-at (point))))
998 (let ((node (button-get button 'elpher-node)))
999 (if (elpher-address-special-p (elpher-node-address node))
1000 (error "Cannot download this link")
1001 (elpher-visit-node (button-get button 'elpher-node)
1002 #'elpher-get-node-download)))
1003 (error "No link selected"))))
1005 (defun elpher-download-current ()
1006 "Download the current page."
1008 (if (elpher-address-special-p (elpher-node-address elpher-current-node))
1009 (error "Cannot download this page")
1010 (elpher-visit-node (elpher-make-node
1011 (elpher-node-display-string elpher-current-node)
1012 (elpher-node-address elpher-current-node)
1013 elpher-current-node)
1014 #'elpher-get-node-download
1017 (defun elpher-build-link-map ()
1018 "Build alist mapping link names to destination nodes in current buffer."
1019 (let ((link-map nil)
1020 (b (next-button (point-min) t)))
1022 (add-to-list 'link-map (cons (button-label b) b))
1023 (setq b (next-button (button-start b))))
1026 (defun elpher-jump ()
1027 "Select a directory entry by name. Similar to the info browser (m)enu command."
1029 (let* ((link-map (elpher-build-link-map)))
1031 (let ((key (let ((completion-ignore-case t))
1032 (completing-read "Directory item/link: "
1034 (if (and key (> (length key) 0))
1035 (let ((b (cdr (assoc key link-map))))
1036 (goto-char (button-start b))
1037 (button-activate b)))))))
1039 (defun elpher-root-dir ()
1040 "Visit root of current server."
1042 (let* ((address (elpher-node-address elpher-current-node))
1043 (host (elpher-address-host address)))
1045 (let ((host (elpher-address-host address))
1046 (selector (elpher-address-selector address))
1047 (port (elpher-address-port address)))
1048 (if (> (length selector) 0)
1049 (let ((root-address (elpher-make-address ?1 "" host port)))
1051 (elpher-make-node (concat "gopher://" host
1052 ":" (number-to-string port)
1055 (error "Already at root directory of current server")))
1056 (error "Command invalid for this page"))))
1058 (defun elpher-bookmarks-current-p ()
1059 "Return non-nil if current node is a bookmarks page."
1060 (eq (elpher-address-type (elpher-node-address elpher-current-node)) 'bookmarks))
1062 (defun elpher-reload-bookmarks ()
1063 "Reload bookmarks if current node is a bookmarks page."
1064 (if (elpher-bookmarks-current-p)
1065 (elpher-reload-current-node)))
1067 (defun elpher-bookmark-current ()
1068 "Bookmark the current node."
1070 (let ((address (elpher-node-address elpher-current-node))
1071 (display-string (elpher-node-display-string elpher-current-node)))
1072 (if (not (elpher-address-special-p address))
1073 (let ((bookmark-display-string (read-string "Bookmark display string: "
1075 (elpher-add-address-bookmark address bookmark-display-string)
1076 (message "Bookmark added."))
1077 (error "Cannot bookmark %s" display-string))))
1079 (defun elpher-bookmark-link ()
1080 "Bookmark the link at point."
1082 (let ((button (button-at (point))))
1084 (let* ((node (button-get button 'elpher-node))
1085 (address (elpher-node-address node))
1086 (display-string (elpher-node-display-string node)))
1087 (if (not (elpher-address-special-p address))
1088 (let ((bookmark-display-string (read-string "Bookmark display string: "
1090 (elpher-add-address-bookmark address bookmark-display-string)
1091 (elpher-reload-bookmarks)
1092 (message "Bookmark added."))
1093 (error "Cannot bookmark %s" display-string)))
1094 (error "No link selected"))))
1096 (defun elpher-unbookmark-current ()
1097 "Remove bookmark for the current node."
1099 (let ((address (elpher-node-address elpher-current-node)))
1100 (unless (elpher-address-special-p address)
1101 (elpher-remove-address-bookmark address)
1102 (message "Bookmark removed."))))
1104 (defun elpher-unbookmark-link ()
1105 "Remove bookmark for the link at point."
1107 (let ((button (button-at (point))))
1109 (let ((node (button-get button 'elpher-node)))
1110 (elpher-remove-address-bookmark (elpher-node-address node))
1111 (elpher-reload-bookmarks)
1112 (message "Bookmark removed."))
1113 (error "No link selected"))))
1115 (defun elpher-bookmarks ()
1116 "Visit bookmarks page."
1118 (switch-to-buffer "*elpher*")
1120 (elpher-make-node "Bookmarks Page" (elpher-make-address 'bookmarks))))
1122 (defun elpher-info-node (node)
1123 "Display information on NODE."
1124 (let ((display-string (elpher-node-display-string node))
1125 (address (elpher-node-address node)))
1126 (if (not (elpher-address-special-p address))
1127 (message "`%s' on %s port %s"
1128 (elpher-address-selector address)
1129 (elpher-address-host address)
1130 (elpher-address-port address))
1131 (message "%s" display-string))))
1133 (defun elpher-info-link ()
1134 "Display information on node corresponding to link at point."
1136 (let ((button (button-at (point))))
1138 (elpher-info-node (button-get button 'elpher-node))
1139 (error "No item selected"))))
1141 (defun elpher-info-current ()
1142 "Display information on current node."
1144 (elpher-info-node elpher-current-node))
1146 (defun elpher-copy-node-url (node)
1147 "Copy URL representation of address of NODE to `kill-ring'."
1148 (let ((address (elpher-node-address node)))
1149 (if (elpher-address-special-p address)
1150 (error (format "Cannot represent %s as URL" (elpher-node-display-string node)))
1151 (let ((url (elpher-get-address-url address)))
1152 (message "Copied \"%s\" to kill-ring/clipboard." url)
1155 (defun elpher-copy-link-url ()
1156 "Copy URL of item at point to `kill-ring'."
1158 (let ((button (button-at (point))))
1160 (elpher-copy-node-url (button-get button 'elpher-node))
1161 (error "No item selected"))))
1163 (defun elpher-copy-current-url ()
1164 "Copy URL of current node to `kill-ring'."
1166 (elpher-copy-node-url elpher-current-node))
1168 (defun elpher-set-coding-system ()
1169 "Specify an explicit character coding system."
1171 (let ((system (read-coding-system "Set coding system to use (default is to autodetect): " nil)))
1172 (setq elpher-user-coding-system system)
1174 (message "Coding system fixed to %s. (Reload to see effect)." system)
1175 (message "Coding system set to autodetect. (Reload to see effect)."))))
1181 (defvar elpher-mode-map
1182 (let ((map (make-sparse-keymap)))
1183 (define-key map (kbd "TAB") 'elpher-next-link)
1184 (define-key map (kbd "<backtab>") 'elpher-prev-link)
1185 (define-key map (kbd "u") 'elpher-back)
1186 (define-key map (kbd "O") 'elpher-root-dir)
1187 (define-key map (kbd "g") 'elpher-go)
1188 (define-key map (kbd "o") 'elpher-go-current)
1189 (define-key map (kbd "r") 'elpher-redraw)
1190 (define-key map (kbd "R") 'elpher-reload)
1191 (define-key map (kbd "T") 'elpher-toggle-tls)
1192 (define-key map (kbd ".") 'elpher-view-raw)
1193 (define-key map (kbd "d") 'elpher-download)
1194 (define-key map (kbd "D") 'elpher-download-current)
1195 (define-key map (kbd "m") 'elpher-jump)
1196 (define-key map (kbd "i") 'elpher-info-link)
1197 (define-key map (kbd "I") 'elpher-info-current)
1198 (define-key map (kbd "c") 'elpher-copy-link-url)
1199 (define-key map (kbd "C") 'elpher-copy-current-url)
1200 (define-key map (kbd "a") 'elpher-bookmark-link)
1201 (define-key map (kbd "A") 'elpher-bookmark-current)
1202 (define-key map (kbd "x") 'elpher-unbookmark-link)
1203 (define-key map (kbd "X") 'elpher-unbookmark-current)
1204 (define-key map (kbd "B") 'elpher-bookmarks)
1205 (define-key map (kbd "S") 'elpher-set-coding-system)
1206 (when (fboundp 'evil-define-key)
1207 (evil-define-key 'motion map
1208 (kbd "TAB") 'elpher-next-link
1209 (kbd "C-]") 'elpher-follow-current-link
1210 (kbd "C-t") 'elpher-back
1211 (kbd "u") 'elpher-back
1212 (kbd "O") 'elpher-root-dir
1213 (kbd "g") 'elpher-go
1214 (kbd "o") 'elpher-go-current
1215 (kbd "r") 'elpher-redraw
1216 (kbd "R") 'elpher-reload
1217 (kbd "T") 'elpher-toggle-tls
1218 (kbd ".") 'elpher-view-raw
1219 (kbd "d") 'elpher-download
1220 (kbd "D") 'elpher-download-current
1221 (kbd "m") 'elpher-jump
1222 (kbd "i") 'elpher-info-link
1223 (kbd "I") 'elpher-info-current
1224 (kbd "c") 'elpher-copy-link-url
1225 (kbd "C") 'elpher-copy-current-url
1226 (kbd "a") 'elpher-bookmark-link
1227 (kbd "A") 'elpher-bookmark-current
1228 (kbd "x") 'elpher-unbookmark-link
1229 (kbd "X") 'elpher-unbookmark-current
1230 (kbd "B") 'elpher-bookmarks
1231 (kbd "S") 'elpher-set-coding-system))
1233 "Keymap for gopher client.")
1235 (define-derived-mode elpher-mode special-mode "elpher"
1236 "Major mode for elpher, an elisp gopher client.
1238 This mode is automatically enabled by the interactive
1239 functions which initialize the gopher client, namely
1240 `elpher', `elpher-go' and `elpher-bookmarks'.")
1242 (when (fboundp 'evil-set-initial-state)
1243 (evil-set-initial-state 'elpher-mode 'motion))
1246 ;;; Main start procedure
1251 "Start elpher with default landing page."
1253 (if (get-buffer "*elpher*")
1254 (switch-to-buffer "*elpher*")
1255 (switch-to-buffer "*elpher*")
1256 (setq elpher-current-node nil)
1257 (let ((start-node (elpher-make-node "Elpher Start Page"
1258 (elpher-make-address 'start))))
1259 (elpher-visit-node start-node)))
1260 "Started Elpher.") ; Otherwise (elpher) evaluates to start page string.
1262 ;;; elpher.el ends here