1 ;;; elpher.el --- A friendly gopher client -*- lexical-binding:t -*-
3 ;; Copyright (C) 2019 Tim Vaughan
5 ;; Author: Tim Vaughan <timv@ughan.xyz>
6 ;; Created: 11 April 2019
8 ;; Keywords: comm gopher
9 ;; Homepage: http://thelambdalab.xyz/elpher
10 ;; Package-Requires: ((emacs "26"))
12 ;; This file is not part of GNU Emacs.
14 ;; This program is free software: you can redistribute it and/or modify
15 ;; it under the terms of the GNU General Public License as published by
16 ;; the Free Software Foundation, either version 3 of the License, or
17 ;; (at your option) any later version.
19 ;; This program is distributed in the hope that it will be useful,
20 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
21 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 ;; GNU General Public License for more details.
24 ;; You should have received a copy of the GNU General Public License
25 ;; along with this file. If not, see <http://www.gnu.org/licenses/>.
29 ;; Elpher aims to provide a practical and friendly gopher client
30 ;; for GNU Emacs. It supports:
32 ;; - intuitive keyboard and mouse-driven browsing,
33 ;; - out-of-the-box compatibility with evil-mode,
34 ;; - clickable web and gopher links *in plain text*,
35 ;; - caching of visited sites,
36 ;; - pleasant and configurable colouring of Gopher directories,
37 ;; - direct visualisation of image files,
38 ;; - a simple bookmark management system,
39 ;; - connections using TLS encryption,
40 ;; - the fledgling Gemini protocol.
42 ;; To launch Elpher, simply use 'M-x elpher'. This will open a start
43 ;; page containing information on key bindings and suggested starting
44 ;; points for your gopher exploration.
46 ;; Full instructions can be found in the Elpher info manual.
48 ;; Elpher is under active development. Any suggestions for
49 ;; improvements are welcome, and can be made on the official
50 ;; project page, gopher://thelambdalab.xyz/1/projects/elpher/.
71 (defconst elpher-version "2.5.1"
72 "Current version of elpher.")
74 (defconst elpher-margin-width 6
75 "Width of left-hand margin used when rendering indicies.")
77 (defconst elpher-type-map
78 '(((gopher ?0) elpher-get-gopher-page elpher-render-text "txt" elpher-text)
79 ((gopher ?1) elpher-get-gopher-page elpher-render-index "/" elpher-index)
80 ((gopher ?4) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
81 ((gopher ?5) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
82 ((gopher ?7) elpher-get-gopher-query-page elpher-render-index "?" elpher-search)
83 ((gopher ?9) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
84 ((gopher ?g) elpher-get-gopher-page elpher-render-image "img" elpher-image)
85 ((gopher ?p) elpher-get-gopher-page elpher-render-image "img" elpher-image)
86 ((gopher ?I) elpher-get-gopher-page elpher-render-image "img" elpher-image)
87 ((gopher ?d) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
88 ((gopher ?P) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
89 ((gopher ?s) elpher-get-gopher-page elpher-render-download "snd" elpher-binary)
90 ((gopher ?h) elpher-get-gopher-page elpher-render-html "htm" elpher-html)
91 (gemini elpher-get-gemini-page elpher-render-gemini "gem" elpher-gemini)
92 (telnet elpher-get-telnet-page nil "tel" elpher-telnet)
93 (other-url elpher-get-other-url-page nil "url" elpher-other-url)
94 ((special bookmarks) elpher-get-bookmarks-page nil "/" elpher-index)
95 ((special start) elpher-get-start-page nil))
96 "Association list from types to getters, renderers, margin codes and index faces.")
99 ;;; Customization group
104 :group 'applications)
106 ;; Face customizations
108 (defface elpher-index
109 '((t :inherit font-lock-keyword-face))
110 "Face used for directory type directory records.")
114 "Face used for text type directory records.")
117 '((t :inherit default))
118 "Face used for info type directory records.")
120 (defface elpher-image
121 '((t :inherit font-lock-string-face))
122 "Face used for image type directory records.")
124 (defface elpher-search
125 '((t :inherit warning))
126 "Face used for search type directory records.")
129 '((t :inherit font-lock-comment-face))
130 "Face used for html type directory records.")
132 (defface elpher-gemini
133 '((t :inherit font-lock-regexp-grouping-backslash))
134 "Face used for html type directory records.")
136 (defface elpher-other-url
137 '((t :inherit font-lock-comment-face))
138 "Face used for other URL type links records.")
140 (defface elpher-telnet
141 '((t :inherit font-lock-function-name-face))
142 "Face used for telnet type directory records.")
144 (defface elpher-binary
145 '((t :inherit font-lock-doc-face))
146 "Face used for binary type directory records.")
148 (defface elpher-unknown
149 '((t :inherit error))
150 "Face used for directory records with unknown/unsupported types.")
152 (defface elpher-margin-key
154 "Face used for directory margin key.")
156 (defface elpher-margin-brackets
157 '((t :inherit shadow))
158 "Face used for brackets around directory margin key.")
160 ;; Other customizations
162 (defcustom elpher-open-urls-with-eww nil
163 "If non-nil, open URL selectors using eww.
164 Otherwise, use the system browser via the BROWSE-URL function."
167 (defcustom elpher-use-header t
168 "If non-nil, display current page information in buffer header."
171 (defcustom elpher-auto-disengage-TLS nil
172 "If non-nil, automatically disengage TLS following an unsuccessful connection.
173 While enabling this may seem convenient, it is also potentially dangerous as it
174 allows switching from an encrypted channel back to plain text without user input."
177 (defcustom elpher-connection-timeout 5
178 "Specifies the number of seconds to wait for a network connection to time out."
181 (defcustom elpher-filter-ansi-from-text nil
182 "If non-nil, filter ANSI escape sequences from text.
183 The default behaviour is to use the ansi-color package to interpret these
192 ;; An elpher "address" object is either a url object or a symbol.
193 ;; Symbol addresses are "special", corresponding to pages generated
194 ;; dynamically for and by elpher. All others represent pages which
195 ;; rely on content retrieved over the network.
197 (defun elpher-address-from-url (url-string)
198 "Create a ADDRESS object corresponding to the given URL-STRING."
199 (let ((data (match-data))) ; Prevent parsing clobbering match data
201 (let ((url (url-generic-parse-url url-string)))
202 (unless (and (not (url-fullness url)) (url-type url))
203 (setf (url-fullness url) t)
204 (setf (url-filename url)
205 (url-unhex-string (url-filename url)))
206 (unless (url-type url)
207 (setf (url-type url) "gopher"))
208 (when (or (equal "gopher" (url-type url))
209 (equal "gophers" (url-type url)))
211 (unless (url-host url)
212 (setf (url-host url) (url-filename url))
213 (setf (url-filename url) ""))
214 (when (or (equal (url-filename url) "")
215 (equal (url-filename url) "/"))
216 (setf (url-filename url) "/1")))
217 (when (equal "gemini" (url-type url))
219 (if (equal (url-filename url) "")
220 (setf (url-filename url) "/"))))
222 (set-match-data data))))
224 (defun elpher-make-gopher-address (type selector host port &optional tls)
225 "Create an ADDRESS object using gopher directory record attributes.
226 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
227 If the optional attribute TLS is non-nil, the address will be marked as
228 requiring gopher-over-TLS."
230 ((and (equal type ?h)
231 (string-prefix-p "URL:" selector))
232 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
234 (elpher-address-from-url
237 ":" (number-to-string port))))
239 (elpher-address-from-url
240 (concat "gopher" (if tls "s" "")
242 ":" (number-to-string port)
246 (defun elpher-make-special-address (type)
247 "Create an ADDRESS object corresponding to the given special address symbol TYPE."
250 (defun elpher-address-to-url (address)
251 "Get string representation of ADDRESS, or nil if ADDRESS is special."
252 (if (not (elpher-address-special-p address))
253 (url-encode-url (url-recreate-url address))
256 (defun elpher-address-type (address)
257 "Retrieve type of ADDRESS object.
258 This is used to determine how to retrieve and render the document the
259 address refers to, via the table `elpher-type-map'."
260 (if (symbolp address)
261 (list 'special address)
262 (let ((protocol (url-type address)))
263 (cond ((or (equal protocol "gopher")
264 (equal protocol "gophers"))
266 (if (member (url-filename address) '("" "/"))
268 (string-to-char (substring (url-filename address) 1)))))
269 ((equal protocol "gemini")
271 ((equal protocol "telnet")
275 (defun elpher-address-protocol (address)
276 "Retrieve the transport protocol for ADDRESS. This is nil for special addresses."
277 (if (symbolp address)
281 (defun elpher-address-filename (address)
282 "Retrieve the filename component of ADDRESS.
283 For gopher addresses this is a combination of the selector type and selector."
284 (if (symbolp address)
286 (url-filename address)))
288 (defun elpher-address-host (address)
289 "Retrieve host from ADDRESS object."
292 (defun elpher-address-port (address)
293 "Retrieve port from ADDRESS object.
294 If no address is defined, returns 0. (This is for compatibility with the URL library.)"
295 (if (symbolp address)
299 (defun elpher-address-special-p (address)
300 "Return non-nil if ADDRESS object is special (e.g. start page, bookmarks page)."
303 (defun elpher-address-gopher-p (address)
304 "Return non-nill if ADDRESS object is a gopher address."
305 (and (not (elpher-address-special-p address))
306 (member (elpher-address-protocol address) '("gopher gophers"))))
308 (defun elpher-gopher-address-selector (address)
309 "Retrieve gopher selector from ADDRESS object."
310 (if (member (url-filename address) '("" "/"))
312 (substring (url-filename address) 2)))
317 (defvar elpher-content-cache (make-hash-table :test 'equal))
318 (defvar elpher-pos-cache (make-hash-table :test 'equal))
320 (defun elpher-get-cached-content (address)
321 "Retrieve the cached content for ADDRESS, or nil if none exists."
322 (gethash address elpher-content-cache))
324 (defun elpher-cache-content (address content)
325 "Set the content cache for ADDRESS to CONTENT."
326 (puthash address content elpher-content-cache))
328 (defun elpher-get-cached-pos (address)
329 "Retrieve the cached cursor position for ADDRESS, or nil if none exists."
330 (gethash address elpher-pos-cache))
332 (defun elpher-cache-pos (address pos)
333 "Set the cursor position cache for ADDRESS to POS."
334 (puthash address pos elpher-pos-cache))
339 (defun elpher-make-page (display-string address)
340 "Create a page with DISPLAY-STRING and ADDRESS."
341 (list display-string address))
343 (defun elpher-page-display-string (page)
344 "Retrieve the display string corresponding to PAGE."
347 (defun elpher-page-address (page)
348 "Retrieve the address corresponding to PAGE."
351 (defvar elpher-current-page nil)
352 (defvar elpher-history nil)
354 (defun elpher-visit-page (page &optional renderer no-history)
355 "Visit PAGE using its own renderer or RENDERER, if non-nil.
356 Additionally, push PAGE onto the stack of previously-visited pages,
357 unless NO-HISTORY is non-nil."
359 (elpher-process-cleanup)
360 (unless (or no-history
361 (equal (elpher-page-address elpher-current-page)
362 (elpher-page-address page)))
363 (push elpher-current-page elpher-history))
364 (setq elpher-current-page page)
365 (let* ((address (elpher-page-address page))
366 (type (elpher-address-type address))
367 (type-record (cdr (assoc type elpher-type-map))))
369 (funcall (car type-record)
373 (elpher-visit-previous-page)
375 (`(gopher ,type-char)
376 (error "Unsupported gopher selector type '%c' for '%s'"
377 type-char (elpher-address-to-url address)))
379 (error "Unsupported address type '%S' for '%s'"
380 other (elpher-address-to-url address)))))))
382 (defun elpher-visit-previous-page ()
383 "Visit the previous page in the history."
384 (let ((previous-page (pop elpher-history)))
386 (elpher-visit-page previous-page nil t)
387 (error "No previous page."))))
389 (defun elpher-reload-current-page ()
390 "Reload the current page, discarding any existing cached content."
391 (elpher-cache-content (elpher-page-address elpher-current-page) nil)
392 (elpher-visit-page elpher-current-page))
394 (defun elpher-save-pos ()
395 "Save the current position of point to the current page."
396 (when elpher-current-page
397 (elpher-cache-pos (elpher-page-address elpher-current-page) (point))))
399 (defun elpher-restore-pos ()
400 "Restore the position of point to that cached in the current page."
401 (let ((pos (elpher-get-cached-pos (elpher-page-address elpher-current-page))))
404 (goto-char (point-min)))))
407 ;;; Buffer preparation
410 (defun elpher-update-header ()
411 "If `elpher-use-header' is true, display current page info in window header."
412 (if elpher-use-header
413 (let* ((display-string (elpher-page-display-string elpher-current-page))
414 (address (elpher-page-address elpher-current-page))
415 (tls-string (if (and (not (elpher-address-special-p address))
416 (member (elpher-address-protocol address)
417 '("gophers" "gemini")))
420 (header (concat display-string
421 (propertize tls-string 'face 'bold))))
422 (setq header-line-format header))))
424 (defmacro elpher-with-clean-buffer (&rest args)
425 "Evaluate ARGS with a clean *elpher* buffer as current."
426 (list 'with-current-buffer "*elpher*"
428 (append (list 'let '((inhibit-read-only t))
430 '(elpher-update-header))
437 (defvar elpher-user-coding-system nil
438 "User-specified coding system to use for decoding text responses.")
440 (defun elpher-decode (string)
441 "Decode STRING using autodetected or user-specified coding system."
442 (decode-coding-string string
443 (if elpher-user-coding-system
444 elpher-user-coding-system
445 (detect-coding-string string t))))
447 (defun elpher-preprocess-text-response (string)
448 "Preprocess text selector response contained in STRING.
449 This involes decoding the character representation, and clearing
450 away CRs and any terminating period."
451 (elpher-decode (replace-regexp-in-string "\n\.\n$" "\n"
452 (replace-regexp-in-string "\r" "" string))))
455 ;;; Network error reporting
458 (defun elpher-network-error (address error)
459 "Display ERROR message following unsuccessful negotiation with ADDRESS.
460 ERROR can be either an error object or a string."
461 (elpher-with-clean-buffer
462 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
463 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
464 (if (stringp error) error (error-message-string error)) "\n"
465 (propertize "\n----------------\n\n" 'face 'error)
466 "Press 'u' to return to the previous page.")))
469 ;;; Gopher selector retrieval
472 (defvar elpher-network-timer nil
473 "Timer used for network connections.")
475 (defun elpher-process-cleanup ()
476 "Immediately shut down any extant elpher process and timers."
477 (let ((p (get-process "elpher-process")))
478 (if p (delete-process p)))
479 (if (timerp elpher-network-timer)
480 (cancel-timer elpher-network-timer)))
482 (defvar elpher-use-tls nil
483 "If non-nil, use TLS to communicate with gopher servers.")
485 (defun elpher-get-selector (address renderer &optional force-ipv4)
486 "Retrieve selector specified by ADDRESS, then render it using RENDERER.
487 If FORCE-IPV4 is non-nil, explicitly look up and use IPv4 address corresponding
489 (when (equal (elpher-address-protocol address) "gophers")
490 (if (gnutls-available-p)
491 (when (not elpher-use-tls)
492 (setq elpher-use-tls t)
493 (message "Engaging TLS gopher mode."))
494 (error "Cannot retrieve TLS gopher selector: GnuTLS not available")))
495 (unless (< (elpher-address-port address) 65536)
496 (error "Cannot retrieve gopher selector: port number > 65536"))
498 (let* ((kill-buffer-query-functions nil)
499 (port (elpher-address-port address))
500 (host (elpher-address-host address))
502 (proc (open-network-stream "elpher-process"
504 (if force-ipv4 (dns-query host) host)
505 (if (> port 0) port 70)
506 :type (if elpher-use-tls 'tls 'plain)
508 (timer (run-at-time elpher-connection-timeout
511 (pcase (process-status proc)
513 (if (and (not (equal (elpher-address-protocol address)
516 (or elpher-auto-disengage-TLS
517 (yes-or-no-p "Could not establish encrypted connection. Disable TLS mode?")))
519 (message "Disabling TLS mode.")
520 (setq elpher-use-tls nil)
521 (elpher-get-selector address renderer))
522 (elpher-network-error address "Could not establish encrypted connection")))
524 (elpher-process-cleanup)
526 (message "Connection timed out. Retrying with IPv4 address.")
527 (elpher-get-selector address renderer t))))))))
528 (setq elpher-network-timer timer)
529 (set-process-coding-system proc 'binary)
530 (set-process-filter proc
531 (lambda (_proc string)
533 (setq selector-string
534 (concat selector-string string))))
535 (set-process-sentinel proc
536 (lambda (_proc event)
537 (condition-case the-error
539 ((string-prefix-p "deleted" event))
540 ((string-prefix-p "open" event)
541 (let ((inhibit-eol-conversion t))
544 (concat (elpher-gopher-address-selector address)
548 (funcall renderer selector-string)
549 (elpher-restore-pos)))
551 (elpher-network-error address the-error))))))
553 (error "Error initiating connection to server"))))
555 (defun elpher-get-gopher-page (renderer)
556 "Getter function for gopher pages.
557 The RENDERER procedure is used to display the contents of the page
558 once they are retrieved from the gopher server."
559 (let* ((address (elpher-page-address elpher-current-page))
560 (content (elpher-get-cached-content address)))
561 (if (and content (funcall renderer nil))
562 (elpher-with-clean-buffer
564 (elpher-restore-pos))
565 (elpher-with-clean-buffer
566 (insert "LOADING... (use 'u' to cancel)"))
567 (condition-case the-error
568 (elpher-get-selector address renderer)
570 (elpher-network-error address the-error))))))
574 (defun elpher-insert-index (string)
575 "Insert the index corresponding to STRING into the current buffer."
576 ;; Should be able to split directly on CRLF, but some non-conformant
577 ;; LF-only servers sadly exist, hence the following.
578 (let ((str-processed (elpher-preprocess-text-response string)))
579 (dolist (line (split-string str-processed "\n"))
581 (unless (= (length line) 0)
582 (let* ((type (elt line 0))
583 (fields (split-string (substring line 1) "\t"))
584 (display-string (elt fields 0))
585 (selector (elt fields 1))
586 (host (elt fields 2))
587 (port (if (elt fields 3)
588 (string-to-number (elt fields 3))
590 (address (elpher-make-gopher-address type selector host port)))
591 (elpher-insert-index-record display-string address)))))))
593 (defun elpher-insert-margin (&optional type-name)
594 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
597 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
599 (propertize "[" 'face 'elpher-margin-brackets)
600 (propertize type-name 'face 'elpher-margin-key)
601 (propertize "]" 'face 'elpher-margin-brackets))))
603 (insert (make-string elpher-margin-width ?\s))))
605 (defun elpher-page-button-help (page)
606 "Return a string containing the help text for a button corresponding to PAGE."
607 (let ((address (elpher-page-address page)))
608 (format "mouse-1, RET: open '%s'" (if (elpher-address-special-p address)
610 (elpher-address-to-url address)))))
612 (defun elpher-insert-index-record (display-string &optional address)
613 "Function to insert an index record into the current buffer.
614 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
615 If ADDRESS is not supplied or nil the record is rendered as an
617 (let* ((type (if address (elpher-address-type address) nil))
618 (type-map-entry (cdr (assoc type elpher-type-map))))
620 (let* ((margin-code (elt type-map-entry 2))
621 (face (elt type-map-entry 3))
622 (page (elpher-make-page display-string address)))
623 (elpher-insert-margin margin-code)
624 (insert-text-button display-string
627 'action #'elpher-click-link
629 'help-echo (elpher-page-button-help page)))
631 ((or '(gopher ?i) 'nil) ;; Information
632 (elpher-insert-margin)
633 (let ((propertized-display-string
634 (propertize display-string 'face 'elpher-info)))
635 (insert (elpher-process-text-for-display propertized-display-string))))
636 (`(gopher ,selector-type) ;; Unknown
637 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
638 (insert (propertize display-string
639 'face 'elpher-unknown)))))
642 (defun elpher-click-link (button)
643 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
644 (let ((page (button-get button 'elpher-page)))
645 (elpher-visit-page page)))
647 (defun elpher-render-index (data &optional _mime-type-string)
648 "Render DATA as an index. MIME-TYPE-STRING is unused."
649 (elpher-with-clean-buffer
652 (elpher-insert-index data)
653 (elpher-cache-content (elpher-page-address elpher-current-page)
658 (defconst elpher-url-regex
659 "\\([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\-_~?/@|#]\\)?\\)?"
660 "Regexp used to locate and buttinofy URLs in text files loaded by elpher.")
662 (defun elpher-buttonify-urls (string)
663 "Turn substrings which look like urls in STRING into clickable buttons."
666 (goto-char (point-min))
667 (while (re-search-forward elpher-url-regex nil t)
668 (let ((page (elpher-make-page (substring-no-properties (match-string 0))
669 (elpher-address-from-url (match-string 0)))))
670 (make-text-button (match-beginning 0)
673 'action #'elpher-click-link
675 'help-echo (elpher-page-button-help page)
679 (defconst elpher-ansi-regex "\x1b\\[[^m]*m"
680 "Wildly incomplete regexp used to strip out some troublesome ANSI escape sequences.")
682 (defun elpher-process-text-for-display (string)
683 "Perform any desired processing of STRING prior to display as text.
684 Currently includes buttonifying URLs and processing ANSI escape codes."
685 (elpher-buttonify-urls (if elpher-filter-ansi-from-text
686 (ansi-color-filter-apply string)
687 (ansi-color-apply string))))
689 (defun elpher-render-text (data &optional _mime-type-string)
690 "Render DATA as text. MIME-TYPE-STRING is unused."
691 (elpher-with-clean-buffer
694 (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
695 (elpher-cache-content
696 (elpher-page-address elpher-current-page)
701 (defun elpher-render-image (data &optional _mime-type-string)
702 "Display DATA as image. MIME-TYPE-STRING is unused."
705 (if (display-images-p)
707 (let ((image (create-image
710 (elpher-with-clean-buffer
712 (elpher-restore-pos))))
713 (elpher-render-download data))))
715 ;; Search retrieval and rendering
717 (defun elpher-get-gopher-query-page (renderer)
718 "Getter for gopher addresses requiring input.
719 The response is rendered using the rendering function RENDERER."
720 (let* ((address (elpher-page-address elpher-current-page))
721 (content (elpher-get-cached-content address))
723 (if (and content (funcall renderer nil))
724 (elpher-with-clean-buffer
727 (message "Displaying cached search results. Reload to perform a new search."))
729 (let* ((query-string (read-string "Query: "))
730 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
731 (search-address (elpher-make-gopher-address ?1
733 (elpher-address-host address)
734 (elpher-address-port address)
735 (equal (elpher-address-type address) "gophers"))))
738 (elpher-with-clean-buffer
739 (insert "LOADING RESULTS... (use 'u' to cancel)"))
740 (elpher-get-selector search-address renderer))
742 (elpher-visit-previous-page))))))
744 ;; Raw server response rendering
746 (defun elpher-render-raw (data &optional mime-type-string)
747 "Display raw DATA in buffer. MIME-TYPE-STRING is also displayed if provided."
750 (elpher-with-clean-buffer
751 (when mime-type-string
752 (insert "MIME type specified by server: '" mime-type-string "'\n"))
754 (goto-char (point-min)))
755 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
757 ;; File save "rendering"
759 (defun elpher-render-download (data &optional _mime-type-string)
760 "Save DATA to file. MIME-TYPE-STRING is unused."
763 (let* ((address (elpher-page-address elpher-current-page))
764 (selector (elpher-gopher-address-selector address)))
765 (elpher-visit-previous-page) ; Do first in case of non-local exits.
766 (let* ((filename-proposal (file-name-nondirectory selector))
767 (filename (read-file-name "Download complete. Save file as: "
769 (if (> (length filename-proposal) 0)
772 (let ((coding-system-for-write 'binary))
773 (with-temp-file filename
775 (message (format "Saved to file %s." filename))))))
779 (defun elpher-render-html (data &optional _mime-type-string)
780 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
781 (elpher-with-clean-buffer
784 (let ((dom (with-temp-buffer
786 (libxml-parse-html-region (point-min) (point-max)))))
787 (shr-insert-document dom)))))
789 ;; Gemini page retrieval
791 (defvar elpher-gemini-redirect-chain)
793 (defun elpher-get-gemini-response (address renderer &optional force-ipv4)
794 "Retrieve gemini ADDRESS, then render using RENDERER.
795 If FORCE-IPV4 is non-nil, explicitly look up and use IPv4 address corresponding
797 (if (not (gnutls-available-p))
798 (error "Cannot establish gemini connection: GnuTLS not available")
799 (unless (< (elpher-address-port address) 65536)
800 (error "Cannot establish gemini connection: port number > 65536"))
802 (let* ((kill-buffer-query-functions nil)
803 (port (elpher-address-port address))
804 (host (elpher-address-host address))
806 (proc (open-network-stream "elpher-process"
808 (if force-ipv4 (dns-query host) host)
809 (if (> port 0) port 1965)
812 (timer (run-at-time elpher-connection-timeout nil
814 (elpher-process-cleanup)
816 ; Try again with IPv4
817 (message "Connection timed out. Retrying with IPv4.")
818 (elpher-get-gemini-response address renderer t))))))
819 (setq elpher-network-timer timer)
820 (set-process-coding-system proc 'binary)
821 (set-process-filter proc
822 (lambda (_proc string)
826 (setq response-string
827 (concat response-string string))))
828 (set-process-sentinel proc
830 (condition-case the-error
832 ((string-prefix-p "open" event) ; request URL
833 (let ((inhibit-eol-conversion t))
836 (concat (elpher-address-to-url address)
838 ((string-prefix-p "deleted" event)) ; do nothing
839 ((and (string-empty-p response-string)
841 ; Try again with IPv4
842 (message "Connection failed. Retrying with IPv4.")
844 (elpher-get-gemini-response address renderer t))
846 (funcall #'elpher-process-gemini-response
849 (elpher-restore-pos)))
851 (elpher-network-error address the-error))))))
853 (error "Error initiating connection to server")))))
855 (defun elpher-parse-gemini-response (response)
856 "Parse the RESPONSE string and return a list of components.
857 The list is of the form (code meta body). A response of nil implies
858 that the response was malformed."
859 (let ((header-end-idx (string-match "\r\n" response)))
861 (let ((header (string-trim (substring response 0 header-end-idx)))
862 (body (substring response (+ header-end-idx 2))))
863 (if (>= (length header) 2)
864 (let ((code (substring header 0 2))
865 (meta (string-trim (substring header 2))))
866 (list code meta body))
867 (error "Malformed response: No response status found in header %s" header)))
868 (error "Malformed response: No CRLF-delimited header found"))))
870 (defun elpher-process-gemini-response (response-string renderer)
871 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
872 (let ((response-components (elpher-parse-gemini-response response-string)))
873 (let ((response-code (elt response-components 0))
874 (response-meta (elt response-components 1))
875 (response-body (elt response-components 2)))
876 (pcase (elt response-code 0)
878 (elpher-with-clean-buffer
879 (insert "Gemini server is requesting input."))
880 (let* ((query-string (read-string (concat response-meta ": ")))
881 (url (elpher-address-to-url (elpher-page-address elpher-current-page)))
882 (query-address (elpher-address-from-url (concat url "?" query-string))))
883 (elpher-get-gemini-response query-address renderer)))
884 (?2 ; Normal response
885 (funcall renderer response-body response-meta))
887 (message "Following redirect to %s" response-meta)
888 (if (>= (length elpher-gemini-redirect-chain) 5)
889 (error "More than 5 consecutive redirects followed"))
890 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
891 (if (member redirect-address elpher-gemini-redirect-chain)
892 (error "Redirect loop detected"))
893 (if (not (string= (elpher-address-protocol redirect-address)
895 (error "Server tried to automatically redirect to non-gemini URL: %s"
897 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
898 (elpher-get-gemini-response redirect-address renderer)))
899 (?4 ; Temporary failure
900 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
901 response-code response-meta))
902 (?5 ; Permanent failure
903 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
904 response-code response-meta))
905 (?6 ; Client certificate required
906 (error "Gemini server requires client certificate (unsupported at this time)"))
908 (error "Gemini server response unknown: %s %s"
909 response-code response-meta))))))
911 (defun elpher-get-gemini-page (renderer)
912 "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
913 (let* ((address (elpher-page-address elpher-current-page))
914 (content (elpher-get-cached-content address)))
915 (condition-case the-error
916 (if (and content (funcall renderer nil))
917 (elpher-with-clean-buffer
919 (elpher-restore-pos))
920 (elpher-with-clean-buffer
921 (insert "LOADING GEMINI... (use 'u' to cancel)"))
922 (setq elpher-gemini-redirect-chain nil)
923 (elpher-get-gemini-response address renderer))
925 (elpher-network-error address the-error)))))
928 (defun elpher-render-gemini (body &optional mime-type-string)
929 "Render gemini response BODY with rendering MIME-TYPE-STRING."
932 (let* ((mime-type-string* (if (or (not mime-type-string)
933 (string-empty-p mime-type-string))
934 "text/gemini; charset=utf-8"
936 (mime-type-split (split-string mime-type-string* ";" t))
937 (mime-type (string-trim (car mime-type-split)))
938 (parameters (mapcar (lambda (s)
939 (let ((key-val (split-string s "=")))
940 (list (downcase (string-trim (car key-val)))
941 (downcase (string-trim (cadr key-val))))))
942 (cdr mime-type-split))))
943 (when (string-prefix-p "text/" mime-type)
944 (setq body (decode-coding-string
946 (if (assoc "charset" parameters)
947 (intern (cadr (assoc "charset" parameters)))
949 (setq body (replace-regexp-in-string "\r" "" body)))
951 ((or "text/gemini" "")
952 (elpher-render-gemini-map body parameters))
954 (elpher-render-html body))
955 ((pred (string-prefix-p "text/"))
956 (elpher-render-gemini-plain-text body parameters))
957 ((pred (string-prefix-p "image/"))
958 (elpher-render-image body))
960 (error "Unsupported MIME type %S" mime-type))))))
962 (defun elpher-gemini-get-link-url (line)
963 "Extract the url portion of LINE, a gemini map file link line."
964 (string-trim (elt (split-string (substring line 2)) 0)))
966 (defun elpher-gemini-get-link-display-string (line)
967 "Extract the display string portion of LINE, a gemini map file link line."
968 (let* ((rest (string-trim (elt (split-string line "=>") 1)))
969 (idx (string-match "[ \t]" rest)))
971 (string-trim (substring rest (+ idx 1)))
974 (defun elpher-collapse-dot-sequences (filename)
975 "Collapse dot sequences in FILENAME.
976 For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
977 (let* ((path (split-string filename "/"))
978 (path-reversed-normalized
979 (seq-reduce (lambda (a b)
980 (cond ((and a (equal b "..") (cdr a)))
981 ((and (not a) (equal b "..")) a) ;leading .. are dropped
985 (string-join (reverse path-reversed-normalized) "/")))
987 (defun elpher-address-from-gemini-url (url)
988 "Extract address from URL with defaults as per gemini map files."
989 (let ((address (url-generic-parse-url url)))
990 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
991 (setf (url-fullness address) t)
992 (if (url-host address) ;if there is an explicit host, filenames are absolute
993 (if (string-empty-p (url-filename address))
994 (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
995 (setf (url-host address) (url-host (elpher-page-address elpher-current-page)))
996 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
997 (setf (url-filename address)
998 (concat (file-name-directory
999 (url-filename (elpher-page-address elpher-current-page)))
1000 (url-filename address)))))
1001 (unless (url-type address)
1002 (setf (url-type address) "gemini"))
1003 (if (equal (url-type address) "gemini")
1004 (setf (url-filename address)
1005 (elpher-collapse-dot-sequences (url-filename address)))))
1008 (defun elpher-render-gemini-map (data _parameters)
1009 "Render DATA as a gemini map file, PARAMETERS is currently unused."
1010 (elpher-with-clean-buffer
1011 (dolist (line (split-string data "\n"))
1012 (if (string-prefix-p "=>" line)
1013 (let* ((url (elpher-gemini-get-link-url line))
1014 (display-string (elpher-gemini-get-link-display-string line))
1015 (address (elpher-address-from-gemini-url url)))
1016 (if (> (length display-string) 0)
1017 (elpher-insert-index-record display-string address)
1018 (elpher-insert-index-record url address)))
1019 (elpher-insert-index-record line)))
1020 (elpher-cache-content
1021 (elpher-page-address elpher-current-page)
1024 (defun elpher-render-gemini-plain-text (data _parameters)
1025 "Render DATA as plain text file. PARAMETERS is currently unused."
1026 (elpher-with-clean-buffer
1027 (insert (elpher-process-text-for-display data))
1028 (elpher-cache-content
1029 (elpher-page-address elpher-current-page)
1032 ;; Other URL page opening
1034 (defun elpher-get-other-url-page (renderer)
1035 "Getter which attempts to open the URL specified by the current page (RENDERER must be nil)."
1037 (elpher-visit-previous-page)
1038 (error "Command not supported for general URLs"))
1039 (let* ((address (elpher-page-address elpher-current-page))
1040 (url (elpher-address-to-url address)))
1042 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1043 (message "Opening URL...")
1044 (if elpher-open-urls-with-eww
1046 (browse-url url)))))
1048 ;; Telnet page connection
1050 (defun elpher-get-telnet-page (renderer)
1051 "Opens a telnet connection to the current page address (RENDERER must be nil)."
1053 (elpher-visit-previous-page)
1054 (error "Command not supported for telnet URLs"))
1055 (let* ((address (elpher-page-address elpher-current-page))
1056 (host (elpher-address-host address))
1057 (port (elpher-address-port address)))
1058 (elpher-visit-previous-page)
1063 ;; Start page page retrieval
1065 (defun elpher-get-start-page (renderer)
1066 "Getter which displays the start page (RENDERER must be nil)."
1068 (elpher-visit-previous-page)
1069 (error "Command not supported for start page"))
1070 (elpher-with-clean-buffer
1071 (insert " --------------------------------------------\n"
1072 " Elpher Gopher Client \n"
1073 " version " elpher-version "\n"
1074 " --------------------------------------------\n"
1076 "Default bindings:\n"
1078 " - TAB/Shift-TAB: next/prev item on current page\n"
1079 " - RET/mouse-1: open item under cursor\n"
1080 " - m: select an item on current page by name (autocompletes)\n"
1081 " - u/mouse-3: return to previous page\n"
1082 " - o/O: visit different selector or the root menu of the current server\n"
1083 " - g: go to a particular gopher address\n"
1084 " - d/D: download item under cursor or current page\n"
1085 " - i/I: info on item under cursor or current page\n"
1086 " - c/C: copy URL representation of item under cursor or current page\n"
1087 " - a/A: bookmark the item under cursor or current page\n"
1088 " - x/X: remove bookmark for item under cursor or current page\n"
1089 " - B: visit the bookmarks page\n"
1090 " - r: redraw current page (using cached contents if available)\n"
1091 " - R: reload current page (regenerates cache)\n"
1092 " - S: set character coding system for gopher (default is to autodetect)\n"
1093 " - T: toggle TLS gopher mode\n"
1094 " - .: display the raw server response for the current page\n"
1096 "Start your exploration of gopher space:\n")
1097 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1098 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1100 "Alternatively, select the following item and enter some search terms:\n")
1101 (elpher-insert-index-record "Veronica-2 Gopher Search Engine"
1102 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1104 "This page contains your bookmarked sites (also visit with B):\n")
1105 (elpher-insert-index-record "Your Bookmarks" 'bookmarks)
1107 "For Elpher release news or to leave feedback, visit:\n")
1108 (elpher-insert-index-record "The Elpher Project Page"
1109 (elpher-make-gopher-address ?1
1115 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1116 (insert-text-button "Elpher info manual"
1122 'help-echo help-string))
1123 (insert " for the full documentation. **\n")
1125 (concat " (This should be available if you have installed Elpher using\n"
1126 " MELPA. Otherwise you will have to install the manual yourself.)\n")
1128 (elpher-restore-pos)))
1130 ;; Bookmarks page page retrieval
1132 (defun elpher-get-bookmarks-page (renderer)
1133 "Getter to load and display the current bookmark list (RENDERER must be nil)."
1135 (elpher-visit-previous-page)
1136 (error "Command not supported for bookmarks page"))
1137 (elpher-with-clean-buffer
1138 (insert "---- Bookmark list ----\n\n")
1139 (let ((bookmarks (elpher-load-bookmarks)))
1141 (dolist (bookmark bookmarks)
1142 (let ((display-string (elpher-bookmark-display-string bookmark))
1143 (address (elpher-address-from-url (elpher-bookmark-url bookmark))))
1144 (elpher-insert-index-record display-string address)))
1145 (insert "No bookmarks found.\n")))
1146 (insert "\n-----------------------\n"
1148 "- u: return to previous page\n"
1149 "- x: delete selected bookmark\n"
1150 "- a: rename selected bookmark\n"
1152 "Bookmarks are stored in the file ")
1153 (let ((filename (locate-user-emacs-file "elpher-bookmarks"))
1154 (help-string "RET,mouse-1: Open bookmarks file in new buffer for editing."))
1155 (insert-text-button filename
1159 (find-file filename))
1161 'help-echo help-string))
1163 (elpher-restore-pos)))
1169 (defun elpher-make-bookmark (display-string url)
1170 "Make an elpher bookmark.
1171 DISPLAY-STRING determines how the bookmark will appear in the
1172 bookmark list, while URL is the url of the entry."
1173 (list display-string url))
1175 (defun elpher-bookmark-display-string (bookmark)
1176 "Get the display string of BOOKMARK."
1179 (defun elpher-set-bookmark-display-string (bookmark display-string)
1180 "Set the display string of BOOKMARK to DISPLAY-STRING."
1181 (setcar bookmark display-string))
1183 (defun elpher-bookmark-url (bookmark)
1184 "Get the address for BOOKMARK."
1187 (defun elpher-save-bookmarks (bookmarks)
1188 "Record the bookmark list BOOKMARKS to the user's bookmark file.
1189 Beware that this completely replaces the existing contents of the file."
1190 (with-temp-file (locate-user-emacs-file "elpher-bookmarks")
1192 (insert "; Elpher bookmarks file\n\n"
1193 "; Bookmarks are stored as a list of (label URL) items.\n"
1194 "; Feel free to edit by hand, but take care to ensure\n"
1195 "; the list structure remains intact.\n\n")
1196 (pp bookmarks (current-buffer))))
1198 (defun elpher-load-bookmarks ()
1199 "Get the list of bookmarks from the users's bookmark file."
1203 (insert-file-contents (locate-user-emacs-file "elpher-bookmarks"))
1204 (goto-char (point-min))
1205 (read (current-buffer))))))
1206 (if (and bookmarks (listp (cadar bookmarks)))
1208 (message "Reading old bookmark file. (Will be updated on write.)")
1209 (mapcar (lambda (old-bm)
1211 (elpher-address-to-url (apply #'elpher-make-gopher-address
1216 (defun elpher-add-address-bookmark (address display-string)
1217 "Save a bookmark for ADDRESS with label DISPLAY-STRING.)))
1218 If ADDRESS is already bookmarked, update the label only."
1219 (let ((bookmarks (elpher-load-bookmarks))
1220 (url (elpher-address-to-url address)))
1221 (let ((existing-bookmark (rassoc (list url) bookmarks)))
1222 (if existing-bookmark
1223 (elpher-set-bookmark-display-string existing-bookmark display-string)
1224 (push (elpher-make-bookmark display-string url) bookmarks)))
1225 (elpher-save-bookmarks bookmarks)))
1227 (defun elpher-remove-address-bookmark (address)
1228 "Remove any bookmark to ADDRESS."
1229 (let ((url (elpher-address-to-url address)))
1230 (elpher-save-bookmarks
1231 (seq-filter (lambda (bookmark)
1232 (not (equal (elpher-bookmark-url bookmark) url)))
1233 (elpher-load-bookmarks)))))
1235 ;;; Interactive procedures
1238 (defun elpher-next-link ()
1239 "Move point to the next link on the current page."
1243 (defun elpher-prev-link ()
1244 "Move point to the previous link on the current page."
1246 (backward-button 1))
1248 (defun elpher-follow-current-link ()
1249 "Open the link or url at point."
1253 (defun elpher-go (host-or-url)
1254 "Go to a particular gopher site HOST-OR-URL.
1255 When run interactively HOST-OR-URL is read from the minibuffer."
1256 (interactive "sGopher or Gemini URL: ")
1257 (let ((page (elpher-make-page host-or-url
1258 (elpher-address-from-url host-or-url))))
1259 (switch-to-buffer "*elpher*")
1260 (elpher-visit-page page)
1263 (defun elpher-go-current ()
1264 "Go to a particular site read from the minibuffer, initialized with the current URL."
1266 (let ((address (elpher-page-address elpher-current-page)))
1267 (if (elpher-address-special-p address)
1268 (error "Command invalid for this page")
1269 (let ((url (read-string "Gopher or Gemini URL: " (elpher-address-to-url address))))
1270 (elpher-visit-page (elpher-make-page url (elpher-address-from-url url)))))))
1272 (defun elpher-redraw ()
1273 "Redraw current page."
1275 (elpher-visit-page elpher-current-page))
1277 (defun elpher-reload ()
1278 "Reload current page."
1280 (elpher-reload-current-page))
1282 (defun elpher-toggle-tls ()
1283 "Toggle TLS encryption mode for gopher."
1285 (setq elpher-use-tls (not elpher-use-tls))
1287 (if (gnutls-available-p)
1288 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
1289 (setq elpher-use-tls nil)
1290 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
1291 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
1293 (defun elpher-view-raw ()
1294 "View raw server response for current page."
1296 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
1297 (error "This page was not generated by a server")
1298 (elpher-visit-page elpher-current-page
1299 #'elpher-render-raw)))
1301 (defun elpher-back ()
1302 "Go to previous site."
1304 (elpher-visit-previous-page))
1306 (defun elpher-download ()
1307 "Download the link at point."
1309 (let ((button (button-at (point))))
1311 (let ((page (button-get button 'elpher-page)))
1312 (if (elpher-address-special-p (elpher-page-address page))
1313 (error "Cannot download %s"
1314 (elpher-page-display-string page))
1315 (elpher-visit-page (button-get button 'elpher-page)
1316 #'elpher-render-download)))
1317 (error "No link selected"))))
1319 (defun elpher-download-current ()
1320 "Download the current page."
1322 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
1323 (error "Cannot download %s"
1324 (elpher-page-display-string elpher-current-page))
1325 (elpher-visit-page (elpher-make-page
1326 (elpher-page-display-string elpher-current-page)
1327 (elpher-page-address elpher-current-page))
1328 #'elpher-render-download
1331 (defun elpher-build-link-map ()
1332 "Build alist mapping link names to destination pages in current buffer."
1333 (let ((link-map nil)
1334 (b (next-button (point-min) t)))
1336 (push (cons (button-label b) b) link-map)
1337 (setq b (next-button (button-start b))))
1340 (defun elpher-jump ()
1341 "Select a directory entry by name. Similar to the info browser (m)enu command."
1343 (let* ((link-map (elpher-build-link-map)))
1345 (let ((key (let ((completion-ignore-case t))
1346 (completing-read "Directory item/link: "
1348 (if (and key (> (length key) 0))
1349 (let ((b (cdr (assoc key link-map))))
1350 (goto-char (button-start b))
1351 (button-activate b)))))))
1353 (defun elpher-root-dir ()
1354 "Visit root of current server."
1356 (let ((address (elpher-page-address elpher-current-page)))
1357 (if (not (elpher-address-special-p address))
1358 (if (or (member (url-filename address) '("/" ""))
1359 (and (elpher-address-gopher-p address)
1360 (= (length (elpher-gopher-address-selector address)) 0)))
1361 (error "Already at root directory of current server")
1362 (let ((address-copy (elpher-address-from-url
1363 (elpher-address-to-url address))))
1364 (setf (url-filename address-copy) "")
1366 (elpher-make-page (elpher-address-to-url address-copy)
1368 (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
1370 (defun elpher-bookmarks-current-p ()
1371 "Return non-nil if current page is a bookmarks page."
1372 (equal (elpher-address-type (elpher-page-address elpher-current-page))
1373 '(special bookmarks)))
1375 (defun elpher-reload-bookmarks ()
1376 "Reload bookmarks if current page is a bookmarks page."
1377 (if (elpher-bookmarks-current-p)
1378 (elpher-reload-current-page)))
1380 (defun elpher-bookmark-current ()
1381 "Bookmark the current page."
1383 (let ((address (elpher-page-address elpher-current-page))
1384 (display-string (elpher-page-display-string elpher-current-page)))
1385 (if (not (elpher-address-special-p address))
1386 (let ((bookmark-display-string (read-string "Bookmark display string: "
1388 (elpher-add-address-bookmark address bookmark-display-string)
1389 (message "Bookmark added."))
1390 (error "Cannot bookmark %s" display-string))))
1392 (defun elpher-bookmark-link ()
1393 "Bookmark the link at point."
1395 (let ((button (button-at (point))))
1397 (let* ((page (button-get button 'elpher-page))
1398 (address (elpher-page-address page))
1399 (display-string (elpher-page-display-string page)))
1400 (if (not (elpher-address-special-p address))
1401 (let ((bookmark-display-string (read-string "Bookmark display string: "
1403 (elpher-add-address-bookmark address bookmark-display-string)
1404 (elpher-reload-bookmarks)
1405 (message "Bookmark added."))
1406 (error "Cannot bookmark %s" display-string)))
1407 (error "No link selected"))))
1409 (defun elpher-unbookmark-current ()
1410 "Remove bookmark for the current page."
1412 (let ((address (elpher-page-address elpher-current-page)))
1413 (unless (elpher-address-special-p address)
1414 (elpher-remove-address-bookmark address)
1415 (message "Bookmark removed."))))
1417 (defun elpher-unbookmark-link ()
1418 "Remove bookmark for the link at point."
1420 (let ((button (button-at (point))))
1422 (let ((page (button-get button 'elpher-page)))
1423 (elpher-remove-address-bookmark (elpher-page-address page))
1424 (elpher-reload-bookmarks)
1425 (message "Bookmark removed."))
1426 (error "No link selected"))))
1428 (defun elpher-bookmarks ()
1429 "Visit bookmarks page."
1431 (switch-to-buffer "*elpher*")
1433 (elpher-make-page "Bookmarks Page" (elpher-make-special-address 'bookmarks))))
1435 (defun elpher-info-page (page)
1436 "Display information on PAGE."
1437 (let ((display-string (elpher-page-display-string page))
1438 (address (elpher-page-address page)))
1439 (if (elpher-address-special-p address)
1440 (message "Special page: %s" display-string)
1441 (message "%s" (elpher-address-to-url address)))))
1443 (defun elpher-info-link ()
1444 "Display information on page corresponding to link at point."
1446 (let ((button (button-at (point))))
1448 (elpher-info-page (button-get button 'elpher-page))
1449 (error "No item selected"))))
1451 (defun elpher-info-current ()
1452 "Display information on current page."
1454 (elpher-info-page elpher-current-page))
1456 (defun elpher-copy-page-url (page)
1457 "Copy URL representation of address of PAGE to `kill-ring'."
1458 (let ((address (elpher-page-address page)))
1459 (if (elpher-address-special-p address)
1460 (error (format "Cannot represent %s as URL" (elpher-page-display-string page)))
1461 (let ((url (elpher-address-to-url address)))
1462 (message "Copied \"%s\" to kill-ring/clipboard." url)
1465 (defun elpher-copy-link-url ()
1466 "Copy URL of item at point to `kill-ring'."
1468 (let ((button (button-at (point))))
1470 (elpher-copy-page-url (button-get button 'elpher-page))
1471 (error "No item selected"))))
1473 (defun elpher-copy-current-url ()
1474 "Copy URL of current page to `kill-ring'."
1476 (elpher-copy-page-url elpher-current-page))
1478 (defun elpher-set-gopher-coding-system ()
1479 "Specify an explicit character coding system for gopher selectors."
1481 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
1482 (setq elpher-user-coding-system system)
1484 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
1485 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
1491 (defvar elpher-mode-map
1492 (let ((map (make-sparse-keymap)))
1493 (define-key map (kbd "TAB") 'elpher-next-link)
1494 (define-key map (kbd "<backtab>") 'elpher-prev-link)
1495 (define-key map (kbd "u") 'elpher-back)
1496 (define-key map [mouse-3] 'elpher-back)
1497 (define-key map (kbd "O") 'elpher-root-dir)
1498 (define-key map (kbd "g") 'elpher-go)
1499 (define-key map (kbd "o") 'elpher-go-current)
1500 (define-key map (kbd "r") 'elpher-redraw)
1501 (define-key map (kbd "R") 'elpher-reload)
1502 (define-key map (kbd "T") 'elpher-toggle-tls)
1503 (define-key map (kbd ".") 'elpher-view-raw)
1504 (define-key map (kbd "d") 'elpher-download)
1505 (define-key map (kbd "D") 'elpher-download-current)
1506 (define-key map (kbd "m") 'elpher-jump)
1507 (define-key map (kbd "i") 'elpher-info-link)
1508 (define-key map (kbd "I") 'elpher-info-current)
1509 (define-key map (kbd "c") 'elpher-copy-link-url)
1510 (define-key map (kbd "C") 'elpher-copy-current-url)
1511 (define-key map (kbd "a") 'elpher-bookmark-link)
1512 (define-key map (kbd "A") 'elpher-bookmark-current)
1513 (define-key map (kbd "x") 'elpher-unbookmark-link)
1514 (define-key map (kbd "X") 'elpher-unbookmark-current)
1515 (define-key map (kbd "B") 'elpher-bookmarks)
1516 (define-key map (kbd "S") 'elpher-set-gopher-coding-system)
1517 (when (fboundp 'evil-define-key*)
1518 (evil-define-key* 'motion map
1519 (kbd "TAB") 'elpher-next-link
1520 (kbd "C-") 'elpher-follow-current-link
1521 (kbd "C-t") 'elpher-back
1522 (kbd "u") 'elpher-back
1523 [mouse-3] 'elpher-back
1524 (kbd "g") 'elpher-go
1525 (kbd "o") 'elpher-go-current
1526 (kbd "r") 'elpher-redraw
1527 (kbd "R") 'elpher-reload
1528 (kbd "T") 'elpher-toggle-tls
1529 (kbd ".") 'elpher-view-raw
1530 (kbd "d") 'elpher-download
1531 (kbd "D") 'elpher-download-current
1532 (kbd "m") 'elpher-jump
1533 (kbd "i") 'elpher-info-link
1534 (kbd "I") 'elpher-info-current
1535 (kbd "c") 'elpher-copy-link-url
1536 (kbd "C") 'elpher-copy-current-url
1537 (kbd "a") 'elpher-bookmark-link
1538 (kbd "A") 'elpher-bookmark-current
1539 (kbd "x") 'elpher-unbookmark-link
1540 (kbd "X") 'elpher-unbookmark-current
1541 (kbd "B") 'elpher-bookmarks
1542 (kbd "S") 'elpher-set-gopher-coding-system))
1544 "Keymap for gopher client.")
1546 (define-derived-mode elpher-mode special-mode "elpher"
1547 "Major mode for elpher, an elisp gopher client.
1549 This mode is automatically enabled by the interactive
1550 functions which initialize the gopher client, namely
1551 `elpher', `elpher-go' and `elpher-bookmarks'.")
1553 (when (fboundp 'evil-set-initial-state)
1554 (evil-set-initial-state 'elpher-mode 'motion))
1557 ;;; Main start procedure
1562 "Start elpher with default landing page."
1564 (if (get-buffer "*elpher*")
1565 (switch-to-buffer "*elpher*")
1566 (switch-to-buffer "*elpher*")
1567 (setq elpher-current-page nil)
1568 (let ((start-page (elpher-make-page "Elpher Start Page"
1569 (elpher-make-special-address 'start))))
1570 (elpher-visit-page start-page)))
1571 "Started Elpher.") ; Otherwise (elpher) evaluates to start page string.
1573 ;;; elpher.el ends here