1 ;;; elpher.el --- Full-featured 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 "25"))
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 full-featured gopher client for GNU Emacs.
32 ;; - intuitive keyboard and mouse-driven browsing,
33 ;; - caching of visited sites (both content and cursor position),
34 ;; - pleasant and configurable colouring of Gopher directories,
35 ;; - direct visualisation of image files,
36 ;; - (m)enu key support, similar to Emacs' info browser,
37 ;; - clickable web and gopher links in plain text.
39 ;; Visited pages are stored as a hierarchy rather than a linear history,
40 ;; meaning that navigation between these pages is quick and easy.
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 ;; Faces, caching options and start page can be configured via
47 ;; the Elpher customization group in Applications.
58 (defconst elpher-version "1.1.0"
59 "Current version of elpher.")
61 (defconst elpher-margin-width 6
62 "Width of left-hand margin used when rendering indicies.")
64 (defconst elpher-start-index
67 (list "i\tfake\tfake\t1"
68 "i --------------------------------------------\tfake\tfake\t1"
69 "i Elpher Gopher Client \tfake\tfake\t1"
70 (format "i version %s\tfake\tfake\t1" elpher-version)
71 "i --------------------------------------------\tfake\tfake\t1"
73 "iUsage:\tfake\tfake\t1"
75 "i - tab/shift-tab: next/prev directory entry on current page\tfake\tfake\t1"
76 "i - RET/mouse-1: open directory entry under cursor\tfake\tfake\t1"
77 "i - m: select a directory entry by name (autocompletes)\tfake\tfake\t1"
78 "i - u: return to parent directory entry\tfake\tfake\t1"
79 "i - O: visit the root directory of the current server\tfake\tfake\t1"
80 "i - g: go to a particular page\tfake\tfake\t1"
81 "i - r: redraw current page (using cached contents if available)\tfake\tfake\t1"
82 "i - R: reload current page (regenerates cache)\tfake\tfake\t1"
83 "i - d: download directory entry under cursor\tfake\tfake\t1"
84 "i - w: display the raw server response for the current page\tfake\tfake\t1"
86 "iPlaces to start exploring Gopherspace:\tfake\tfake\t1"
88 "1Floodgap Systems Gopher Server\t\tgopher.floodgap.com\t70"
90 "iAlternatively, select the following item and enter some\tfake\tfake\t1"
91 "isearch terms:\tfake\tfake\t1"
93 "7Veronica-2 Gopher Search Engine\t/v2/vs\tgopher.floodgap.com\t70"
96 "Source for elpher start page.")
98 (defconst elpher-type-map
99 '((?0 elpher-get-text-node "T" elpher-text)
100 (?1 elpher-get-index-node "/" elpher-index)
101 (?g elpher-get-image-node "im" elpher-image)
102 (?p elpher-get-image-node "im" elpher-image)
103 (?I elpher-get-image-node "im" elpher-image)
104 (?4 elpher-get-node-download "B" elpher-binary)
105 (?5 elpher-get-node-download "B" elpher-binary)
106 (?7 elpher-get-search-node "?" elpher-search)
107 (?8 elpher-get-telnet-node "?" elpher-telnet)
108 (?9 elpher-get-node-download "B" elpher-binary)
109 (?h elpher-get-url-node "W" elpher-url))
110 "Association list from types to getters, margin codes and index faces.")
113 ;;; Customization group
118 :group 'applications)
120 ;; Face customizations
122 (defface elpher-index
123 '((t :inherit org-drawer))
124 "Face used for directory type directory records.")
127 '((t :inherit org-tag))
128 "Face used for text type directory records.")
131 '((t :inherit org-default))
132 "Face used for info type directory records.")
134 (defface elpher-image
135 '((t :inherit org-level-4))
136 "Face used for image type directory records.")
138 (defface elpher-search
139 '((t :inherit org-level-5))
140 "Face used for search type directory records.")
143 '((t :inherit org-level-6))
144 "Face used for url type directory records.")
146 (defface elpher-telnet
147 '((t :inherit org-level-6))
148 "Face used for telnet type directory records.")
150 (defface elpher-binary
151 '((t :inherit org-level-7))
152 "Face used for binary type directory records.")
154 (defface elpher-unknown
155 '((t :inherit org-warning))
156 "Face used for directory records with unknown/unsupported types.")
158 (defface elpher-margin-key
159 '((t :inherit org-tag))
160 "Face used for directory margin key.")
162 (defface elpher-margin-brackets
163 '((t :inherit org-special-keyword))
164 "Face used for brackets around directory margin key.")
166 ;; Other customizations
168 (defcustom elpher-open-urls-with-eww nil
169 "If non-nil, open URL selectors using eww.
170 Otherwise, use the system browser via the BROWSE-URL function."
173 (defcustom elpher-buttonify-urls-in-directories nil
174 "If non-nil, turns URLs matched in directories into clickable buttons."
177 (defcustom elpher-cache-images nil
178 "If non-nil, cache images in memory in the same way as other content."
181 (defcustom elpher-start-address nil
182 "If nil, the default start directory is shown when Elpher is started.
183 Otherwise, a list containing the selector, host and port of a directory to
184 use as the start page."
185 :type '(list string string integer))
193 (defun elpher-make-address (selector host port)
194 "Create an address of a gopher object with SELECTOR, HOST and PORT."
195 (list selector host port))
197 (defun elpher-address-selector (address)
198 "Retrieve selector from ADDRESS."
201 (defun elpher-address-host (address)
202 "Retrieve host from ADDRESS."
205 (defun elpher-address-port (address)
206 "Retrieve port from ADDRESS."
211 (defun elpher-make-node (parent address getter &optional content pos)
212 "Create a node in the gopher page hierarchy.
214 PARENT specifies the parent of the node, ADDRESS specifies the address of
215 the gopher page, GETTER provides the getter function used to obtain this
218 The optional arguments CONTENT and POS can be used to fill the cached
219 content and cursor position fields of the node."
220 (list parent address getter content pos))
222 (defun elpher-node-parent (node)
223 "Retrieve the parent node of NODE."
226 (defun elpher-node-address (node)
227 "Retrieve the address of NODE."
230 (defun elpher-node-getter (node)
231 "Retrieve the preferred getter function of NODE."
234 (defun elpher-node-content (node)
235 "Retrieve the cached content of NODE, or nil if none exists."
238 (defun elpher-node-pos (node)
239 "Retrieve the cached cursor position for NODE, or nil if none exists."
242 (defun elpher-set-node-content (node content)
243 "Set the content cache of NODE to CONTENT."
244 (setcar (nthcdr 3 node) content))
246 (defun elpher-set-node-pos (node pos)
247 "Set the cursor position cache of NODE to POS."
248 (setcar (nthcdr 4 node) pos))
250 ;; Node graph traversal
252 (defvar elpher-current-node nil)
254 (defun elpher-visit-node (node &optional getter)
255 "Visit NODE using its own getter or GETTER, if non-nil."
257 (elpher-process-cleanup)
258 (setq elpher-current-node node)
261 (funcall (elpher-node-getter node))))
263 (defun elpher-visit-parent-node ()
264 "Visit the parent of the current node."
265 (let ((parent-node (elpher-node-parent elpher-current-node)))
267 (elpher-visit-node parent-node))))
269 (defun elpher-reload-current-node ()
270 "Reload the current node, discarding any existing cached content."
271 (elpher-set-node-content elpher-current-node nil)
272 (elpher-visit-node elpher-current-node))
274 (defun elpher-save-pos ()
275 "Save the current position of point to the current node."
276 (when elpher-current-node
277 (elpher-set-node-pos elpher-current-node (point))))
279 (defun elpher-restore-pos ()
280 "Restore the position of point to that cached in the current node."
281 (let ((pos (elpher-node-pos elpher-current-node)))
284 (goto-char (point-min)))))
287 ;;; Buffer preparation
290 (defmacro elpher-with-clean-buffer (&rest args)
291 "Evaluate ARGS with a clean *elpher* buffer as current."
292 (list 'with-current-buffer "*elpher*"
294 (append (list 'let '((inhibit-read-only t))
302 (defun elpher-insert-index (string)
303 "Insert the index corresponding to STRING into the current buffer."
304 ;; Should be able to split directly on CRLF, but some non-conformant
305 ;; LF-only servers sadly exist, hence the following.
306 (let* ((str-no-period (replace-regexp-in-string "\r\n\.\r\n$" "\r\n" string))
307 (str-no-cr (replace-regexp-in-string "\r" "" str-no-period)))
308 (dolist (line (split-string str-no-cr "\n"))
309 (unless (= (length line) 0)
310 (elpher-insert-index-record line)))))
312 (defun elpher-insert-margin (&optional type-name)
313 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
316 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
318 (propertize "[" 'face 'elpher-margin-brackets)
319 (propertize type-name 'face 'elpher-margin-key)
320 (propertize "]" 'face 'elpher-margin-brackets))))
322 (insert (make-string elpher-margin-width ?\s))))
324 (defun elpher-node-button-help (node)
325 "Return a string containing the help text for a button corresponding to NODE."
326 (let ((address (elpher-node-address node)))
327 (if (eq (elpher-node-getter node) #'elpher-get-url-node)
328 (let ((url (cadr (split-string (elpher-address-selector address) "URL:"))))
329 (format "mouse-1, RET: open url '%s'" url))
330 (format "mouse-1, RET: open '%s' on %s port %s"
331 (elpher-address-selector address)
332 (elpher-address-host address)
333 (elpher-address-port address)))))
335 (defun elpher-insert-index-record (line)
336 "Insert the index record corresponding to LINE into the current buffer."
337 (let* ((type (elt line 0))
338 (fields (split-string (substring line 1) "\t"))
339 (display-string (elt fields 0))
340 (selector (elt fields 1))
341 (host (elt fields 2))
342 (port (string-to-number (elt fields 3))))
343 (elpher-insert-index-record-helper type display-string selector host port)))
345 (defun elpher-insert-index-record-helper (type display-string selector host port)
346 "Helper function to insert an index record into the current buffer.
347 The contents of the record are dictated by TYPE, DISPLAY-STRING, SELECTOR, HOST
350 This function is essentially the second half of `elpher-insert-index-record',
351 but broken out so that it can be used by other functions to construct indices
353 (let ((address (elpher-make-address selector host port))
354 (type-map-entry (alist-get type elpher-type-map)))
356 (let* ((getter (car type-map-entry))
357 (margin-code (cadr type-map-entry))
358 (face (caddr type-map-entry))
359 (node (elpher-make-node elpher-current-node address getter)))
360 (elpher-insert-margin margin-code)
361 (insert-text-button display-string
364 'elpher-node-type type
365 'action #'elpher-click-link
367 'help-echo (elpher-node-button-help node)))
369 (?i (elpher-insert-margin) ;; Information
371 (if elpher-buttonify-urls-in-directories
372 (elpher-buttonify-urls display-string)
374 'face 'elpher-info)))
375 (tp (elpher-insert-margin (concat (char-to-string tp) "?"))
376 (insert (propertize display-string
377 'face 'elpher-unknown-face)))))
380 (defun elpher-click-link (button)
381 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
382 (let ((node (button-get button 'elpher-node)))
383 (elpher-visit-node node)))
386 ;;; Selector retrieval (all kinds)
389 (defun elpher-process-cleanup ()
390 "Immediately shut down any extant elpher process."
391 (let ((p (get-process "elpher-process")))
392 (if p (delete-process p))))
394 (defvar elpher-selector-string)
396 (defun elpher-get-selector (address after)
397 "Retrieve selector specified by ADDRESS, then execute AFTER.
398 The result is stored as a string in the variable ‘elpher-selector-string’."
399 (setq elpher-selector-string "")
400 (make-network-process
401 :name "elpher-process"
402 :host (elpher-address-host address)
403 :service (elpher-address-port address)
404 :filter (lambda (proc string)
405 (setq elpher-selector-string (concat elpher-selector-string string)))
407 (process-send-string "elpher-process"
408 (concat (elpher-address-selector address) "\n")))
412 (defun elpher-get-index-node ()
413 "Getter which retrieves the current node contents as an index."
414 (let ((content (elpher-node-content elpher-current-node))
415 (address (elpher-node-address elpher-current-node)))
418 (elpher-with-clean-buffer
420 (elpher-restore-pos)))
423 (elpher-with-clean-buffer
424 (insert "LOADING DIRECTORY..."))
425 (elpher-get-selector address
427 (unless (string-prefix-p "deleted" event)
428 (elpher-with-clean-buffer
429 (elpher-insert-index elpher-selector-string)
431 (elpher-set-node-content elpher-current-node
432 (buffer-string)))))))
434 (elpher-with-clean-buffer
435 (elpher-insert-index elpher-start-index)
437 (elpher-set-node-content elpher-current-node
438 (buffer-string))))))))
442 (defconst elpher-url-regex
443 "\\([a-zA-Z]+\\)://\\([a-zA-Z0-9.\-]+\\)\\(?3::[0-9]+\\)?\\(?4:/[^ \r\n\t(),]*\\)?"
444 "Regexp used to locate and buttinofy URLs in text files loaded by elpher.")
446 (defun elpher-make-node-from-matched-url (parent &optional string)
447 "Convert most recent `elpher-url-regex' match to a node.
449 PARENT defines the node to set as the parent to the new node.
451 If STRING is non-nil, this is given as an argument to all `match-string'
452 calls, as is necessary if the match is performed by `string-match'."
453 (let ((url (match-string 0 string))
454 (protocol (downcase (match-string 1 string))))
455 (if (string= protocol "gopher")
456 (let* ((host (match-string 2 string))
457 (port (if (> (length (match-string 3 string)) 1)
458 (string-to-number (substring (match-string 3 string) 1))
460 (type-and-selector (match-string 4 string))
461 (type (if (> (length type-and-selector) 1)
462 (elt type-and-selector 1)
464 (selector (if (> (length type-and-selector) 1)
465 (substring type-and-selector 2)
467 (address (elpher-make-address selector host port))
468 (getter (car (alist-get type elpher-type-map))))
469 (elpher-make-node elpher-current-node address getter))
470 (let* ((host (match-string 2 string))
471 (port (if (> (length (match-string 3 string)) 1)
472 (string-to-number (substring (match-string 3 string) 1))
474 (selector (concat "URL:" url))
475 (address (elpher-make-address selector host port))
476 (getter (car (alist-get ?h elpher-type-map))))
477 (elpher-make-node elpher-current-node address getter)))))
480 (defun elpher-buttonify-urls (string)
481 "Turn substrings which look like urls in STRING into clickable buttons."
484 (goto-char (point-min))
485 (while (re-search-forward elpher-url-regex nil t)
486 (let ((node (elpher-make-node-from-matched-url elpher-current-node)))
487 (make-text-button (match-beginning 0)
490 'action #'elpher-click-link
492 'help-echo (elpher-node-button-help node))))
495 (defun elpher-process-text (string)
496 "Remove CRs and trailing period from the gopher text document STRING."
497 (let* ((chopped-str (replace-regexp-in-string "\r\n\.\r\n$" "\r\n" string))
498 (cleaned-str (replace-regexp-in-string "\r" "" chopped-str)))
499 (elpher-buttonify-urls cleaned-str)))
501 (defun elpher-get-text-node ()
502 "Getter which retrieves the current node contents as a text document."
503 (let ((content (elpher-node-content elpher-current-node))
504 (address (elpher-node-address elpher-current-node)))
507 (elpher-with-clean-buffer
509 (elpher-restore-pos)))
511 (elpher-with-clean-buffer
512 (insert "LOADING TEXT..."))
513 (elpher-get-selector address
515 (unless (string-prefix-p "deleted" event)
516 (elpher-with-clean-buffer
517 (insert (elpher-process-text elpher-selector-string))
519 (elpher-set-node-content elpher-current-node
520 (buffer-string))))))))))
524 (defun elpher-get-image-node ()
525 "Getter which retrieves the current node contents as an image to view."
526 (let ((content (elpher-node-content elpher-current-node))
527 (address (elpher-node-address elpher-current-node)))
530 (elpher-with-clean-buffer
531 (insert-image content)
532 (elpher-restore-pos)))
533 (if (display-images-p)
535 (elpher-with-clean-buffer
536 (insert "LOADING IMAGE..."))
537 (elpher-get-selector address
539 (unless (string-prefix-p "deleted" event)
540 (let ((image (create-image
541 (encode-coding-string elpher-selector-string
544 (elpher-with-clean-buffer
546 (elpher-restore-pos))
547 (if elpher-cache-images
548 (elpher-set-node-content elpher-current-node
550 (elpher-get-node-download)))))
554 (defun elpher-get-search-node ()
555 "Getter which submits a search query to the address of the current node."
556 (let ((content (elpher-node-content elpher-current-node))
557 (address (elpher-node-address elpher-current-node))
561 (elpher-with-clean-buffer
563 (elpher-restore-pos))
564 (message "Displaying cached search results. Reload to perform a new search."))
566 (let* ((query-string (read-string "Query: "))
567 (query-selector (concat (elpher-address-selector address) "\t" query-string))
568 (search-address (elpher-make-address query-selector
569 (elpher-address-host address)
570 (elpher-address-port address))))
572 (elpher-with-clean-buffer
573 (insert "LOADING RESULTS..."))
574 (elpher-get-selector search-address
576 (unless (string-prefix-p "deleted" event)
577 (elpher-with-clean-buffer
578 (elpher-insert-index elpher-selector-string))
579 (goto-char (point-min))
580 (elpher-set-node-content elpher-current-node
583 (elpher-visit-parent-node))))))
585 ;; Raw server response retrieval
587 (defun elpher-get-node-raw ()
588 "Getter which retrieves the raw server response for the current node."
589 (let* ((content (elpher-node-content elpher-current-node))
590 (address (elpher-node-address elpher-current-node)))
591 (elpher-with-clean-buffer
592 (insert "LOADING RAW SERVER RESPONSE..."))
594 (elpher-get-selector address
596 (unless (string-prefix-p "deleted" event)
597 (elpher-with-clean-buffer
598 (insert elpher-selector-string)
599 (goto-char (point-min))))))
601 (elpher-with-clean-buffer
602 (insert elpher-start-index))
603 (goto-char (point-min)))))
604 (message "Displaying raw server response. Reload or redraw to return to standard view."))
606 ;; File export retrieval
608 (defvar elpher-download-filename)
610 (defun elpher-get-node-download ()
611 "Getter which retrieves the current node and writes the result to a file."
612 (let* ((address (elpher-node-address elpher-current-node))
613 (selector (elpher-address-selector address)))
614 (elpher-visit-parent-node) ; Do first in case of non-local exits.
615 (let* ((filename-proposal (file-name-nondirectory selector))
616 (filename (read-file-name "Save file as: "
618 (if (> (length filename-proposal) 0)
621 (message "Downloading...")
622 (setq elpher-download-filename filename)
623 (elpher-get-selector address
625 (let ((coding-system-for-write 'binary))
626 (with-temp-file elpher-download-filename
627 (insert elpher-selector-string)
628 (message (format "Download complate, saved to file %s."
629 elpher-download-filename)))))))))
633 (defun elpher-get-url-node ()
634 "Getter which attempts to open the URL specified by the current node."
635 (let* ((address (elpher-node-address elpher-current-node))
636 (selector (elpher-address-selector address)))
637 (elpher-visit-parent-node) ; Do first in case of non-local exits.
638 (let ((url (elt (split-string selector "URL:") 1)))
639 (if elpher-open-urls-with-eww
643 ;; Telnet node connection
645 (defun elpher-get-telnet-node ()
646 "Getter which opens a telnet connection to the server specified by the current node."
647 (let* ((address (elpher-node-address elpher-current-node))
648 (host (elpher-address-host address))
649 (port (elpher-address-port address)))
650 (elpher-visit-parent-node)
657 (defun elpher-make-bookmark (type display-string address)
658 "Make an elpher bookmark.
659 DISPLAY-STRING determines how the bookmark will appear in the bookmark list.
661 TYPE specifies how the entry will be retrieved when selected, and is
662 specified using the standard gopher entry type characters.
664 ADDRESS is the address of the entry."
665 (list type display-string address))
667 (defun elpher-bookmark-type (bookmark)
668 "Ge the type of BOOKMARK."
671 (defun elpher-bookmark-display-string (bookmark)
672 "Get the display string of BOOKMARK."
675 (defun elpher-bookmark-address (bookmark)
676 "Get the address for BOOKMARK."
679 (defun elpher-save-bookmarks (bookmarks)
680 "Record the bookmark list BOOKMARKS to the user's bookmark file.
681 Beware that this completely replaces the existing contents of the file."
682 (with-temp-file (locate-user-emacs-file "elpher-bookmarks")
684 (pp bookmarks (current-buffer))))
686 (defun elpher-load-bookmarks ()
687 "Get the list of bookmarks from the users's bookmark file."
690 (insert-file-contents (locate-user-emacs-file "elpher-bookmarks"))
691 (goto-char (point-min))
692 (read (current-buffer)))))
694 (defun elpher-add-bookmark (bookmark)
695 "Add BOOKMARK to the saved list of bookmarks."
696 (let ((bookmarks (elpher-load-bookmarks)))
697 (add-to-list 'bookmarks bookmark)
698 (elpher-save-bookmarks bookmarks)))
700 (defun elpher-remove-bookmark (bookmark)
701 "Remove BOOKMARK from the saved list of bookmarks."
702 (elpher-save-bookmarks
703 (seq-filter (lambda (this-bookmark)
704 (not (equal bookmark this-bookmark)))
705 (elpher-load-bookmarks))))
707 (defun elpher-display-bookmarks ()
708 "Display saved bookmark list."
710 (elpher-with-clean-buffer
712 "Use 'u' to return to the previous page.\n\n"
713 "---- Bookmark list ----\n\n")
714 (let ((bookmarks (elpher-load-bookmarks)))
716 (dolist (bookmark (elpher-load-bookmarks))
717 (let ((type (elpher-bookmark-type bookmark))
718 (display-string (elpher-bookmark-display-string bookmark))
719 (address (elpher-bookmark-address bookmark)))
720 (elpher-insert-index-record-helper type display-string
721 (elpher-address-selector address)
722 (elpher-address-host address)
723 (elpher-address-port address))))
724 (insert "No bookmarks found.\n")))
725 (insert "\n-----------------------")
726 (goto-char (point-min))
729 (defun elpher-bookmark-link ()
730 "Bookmark the link at point."
732 (let ((button (button-at (point))))
734 (let ((node (button-get button 'elpher-node))
735 (type (button-get button 'elpher-node-type))
736 (label (button-label button)))
740 (elpher-make-bookmark type
742 (elpher-node-address node)))
743 (message "Bookmarked \"%s\"" label))
744 (error "Can only bookmark gopher links, not general URLs")))
745 (error "No link selected"))))
747 (defun elpher-unbookmark-link ()
748 "Remove bookmark for the link at point."
750 (let ((button (button-at (point))))
752 (let ((node (button-get button 'elpher-node))
753 (type (button-get button 'elpher-node-type)))
755 (elpher-remove-bookmark
756 (elpher-make-bookmark type
757 (button-label button)
758 (elpher-node-address node)))
759 (error "Can only bookmark gopher links, not general URLs")))
760 (error "No link selected"))))
762 ;;; Interactive navigation procedures
765 (defun elpher-next-link ()
766 "Move point to the next link on the current page."
770 (defun elpher-prev-link ()
771 "Move point to the previous link on the current page."
775 (defun elpher-follow-current-link ()
776 "Open the link or url at point."
781 "Go to a particular gopher site."
784 (let ((host-or-url (read-string "Gopher host or URL: ")))
785 (if (string-match elpher-url-regex host-or-url)
786 (elpher-make-node-from-matched-url elpher-current-node
788 (let ((selector (read-string "Selector (default none): " nil nil ""))
789 (port (string-to-number (read-string "Port (default 70): "
791 (elpher-make-node elpher-current-node
792 (elpher-make-address selector host-or-url port)
793 #'elpher-get-index-node))))))
794 (switch-to-buffer "*elpher*")
795 (elpher-visit-node node)))
797 (defun elpher-redraw ()
798 "Redraw current page."
800 (if elpher-current-node
801 (elpher-visit-node elpher-current-node)
802 (message "No current site.")))
804 (defun elpher-reload ()
805 "Reload current page."
807 (if elpher-current-node
808 (elpher-reload-current-node)
809 (message "No current site.")))
811 (defun elpher-view-raw ()
812 "View current page as plain text."
814 (if elpher-current-node
815 (elpher-visit-node elpher-current-node
816 #'elpher-get-node-raw)
817 (message "No current site.")))
819 (defun elpher-back ()
820 "Go to previous site."
822 (if (elpher-node-parent elpher-current-node)
823 (elpher-visit-parent-node)
824 (error "No previous site")))
826 (defun elpher-download ()
827 "Download the link at point."
829 (let ((button (button-at (point))))
831 (let ((node (button-get button 'elpher-node)))
833 (elpher-visit-node (button-get button 'elpher-node)
834 #'elpher-get-node-download)
835 (error "Can only download gopher links, not general URLs")))
836 (error "No link selected"))))
838 (defun elpher-build-link-map ()
839 "Build alist mapping link names to destination nodes in current buffer."
841 (b (next-button (point-min) t)))
843 (add-to-list 'link-map (cons (button-label b) b))
844 (setq b (next-button (button-start b))))
847 (defun elpher-menu ()
848 "Select a directory entry by name. Similar to the info browser (m)enu command."
850 (let* ((link-map (elpher-build-link-map)))
852 (let ((key (let ((completion-ignore-case t))
853 (completing-read "Directory entry/link (tab to autocomplete): "
855 (if (and key (> (length key) 0))
856 (let ((b (cdr (assoc key link-map))))
857 (goto-char (button-start b))
858 (button-activate b)))))))
860 (defun elpher-root-dir ()
861 "Visit root of current server."
863 (let ((address (elpher-node-address elpher-current-node)))
865 (let ((host (elpher-address-host address))
866 (selector (elpher-address-selector address))
867 (port (elpher-address-port address)))
868 (if (> (length selector) 0)
869 (let ((root-address (elpher-make-address "" host port)))
870 (elpher-visit-node (elpher-make-node elpher-current-node
872 #'elpher-get-index-node)))
873 (error "Already at root directory of current server")))
874 (error "Command invalid for Elpher start page"))))
880 (defvar elpher-mode-map
881 (let ((map (make-sparse-keymap)))
882 (define-key map (kbd "TAB") 'elpher-next-link)
883 (define-key map (kbd "<backtab>") 'elpher-prev-link)
884 (define-key map (kbd "u") 'elpher-back)
885 (define-key map (kbd "O") 'elpher-root-dir)
886 (define-key map (kbd "g") 'elpher-go)
887 (define-key map (kbd "r") 'elpher-redraw)
888 (define-key map (kbd "R") 'elpher-reload)
889 (define-key map (kbd "w") 'elpher-view-raw)
890 (define-key map (kbd "d") 'elpher-download)
891 (define-key map (kbd "m") 'elpher-menu)
892 (when (fboundp 'evil-define-key)
893 (evil-define-key 'motion map
894 (kbd "TAB") 'elpher-next-link
895 (kbd "C-]") 'elpher-follow-current-link
896 (kbd "C-t") 'elpher-back
897 (kbd "u") 'elpher-back
898 (kbd "O") 'elpher-root-dir
900 (kbd "r") 'elpher-redraw
901 (kbd "R") 'elpher-reload
902 (kbd "w") 'elpher-view-raw
903 (kbd "d") 'elpher-download
904 (kbd "m") 'elpher-menu
905 (kbd "a") 'elpher-bookmark-link
906 (kbd "x") 'elpher-unbookmark-link
907 (kbd "B") 'elpher-display-bookmarks))
909 "Keymap for gopher client.")
911 (define-derived-mode elpher-mode special-mode "elpher"
912 "Major mode for elpher, an elisp gopher client.")
914 (when (fboundp 'evil-set-initial-state)
915 (evil-set-initial-state 'elpher-mode 'motion))
917 ;;; Main start procedure
922 "Start elpher with default landing page."
924 (if (get-buffer "*elpher*")
925 (switch-to-buffer "*elpher*")
926 (switch-to-buffer "*elpher*")
927 (setq elpher-current-node nil)
928 (let ((start-node (elpher-make-node nil
930 #'elpher-get-index-node)))
931 (elpher-visit-node start-node)))
932 "Started Elpher.") ; Otherwise (elpher) evaluates to start page string.
934 ;;; elpher.el ends here