1 ;;; elpher.el --- A friendly gopher and gemini client -*- lexical-binding:t -*-
3 ;; Copyright (C) 2019-2020 Tim Vaughan
5 ;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
6 ;; Created: 11 April 2019
8 ;; Keywords: comm gopher
9 ;; Homepage: http://thelambdalab.xyz/elpher
10 ;; Package-Requires: ((emacs "26.2"))
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 and gemini
30 ;; client 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 ;; - gopher connections using TLS encryption,
40 ;; - the fledgling Gemini protocol,
41 ;; - the greybeard Finger protocol.
43 ;; To launch Elpher, simply use 'M-x elpher'. This will open a start
44 ;; page containing information on key bindings and suggested starting
45 ;; points for your gopher exploration.
47 ;; Full instructions can be found in the Elpher info manual.
49 ;; Elpher is under active development. Any suggestions for
50 ;; improvements are welcome, and can be made on the official
51 ;; project page, gopher://thelambdalab.xyz/1/projects/elpher/.
75 (defconst elpher-version "2.10.2"
76 "Current version of elpher.")
78 (defconst elpher-margin-width 6
79 "Width of left-hand margin used when rendering indicies.")
81 (defconst elpher-type-map
82 '(((gopher ?0) elpher-get-gopher-page elpher-render-text "txt" elpher-text)
83 ((gopher ?1) elpher-get-gopher-page elpher-render-index "/" elpher-index)
84 ((gopher ?4) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
85 ((gopher ?5) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
86 ((gopher ?7) elpher-get-gopher-query-page elpher-render-index "?" elpher-search)
87 ((gopher ?9) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
88 ((gopher ?g) elpher-get-gopher-page elpher-render-image "img" elpher-image)
89 ((gopher ?p) elpher-get-gopher-page elpher-render-image "img" elpher-image)
90 ((gopher ?I) elpher-get-gopher-page elpher-render-image "img" elpher-image)
91 ((gopher ?d) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
92 ((gopher ?P) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
93 ((gopher ?s) elpher-get-gopher-page elpher-render-download "snd" elpher-binary)
94 ((gopher ?h) elpher-get-gopher-page elpher-render-html "htm" elpher-html)
95 (gemini elpher-get-gemini-page elpher-render-gemini "gem" elpher-gemini)
96 (finger elpher-get-finger-page elpher-render-text "txt" elpher-text)
97 (telnet elpher-get-telnet-page nil "tel" elpher-telnet)
98 (other-url elpher-get-other-url-page nil "url" elpher-other-url)
99 ((special bookmarks) elpher-get-bookmarks-page nil "/" elpher-index)
100 ((special start) elpher-get-start-page nil))
101 "Association list from types to getters, renderers, margin codes and index faces.")
104 ;;; Customization group
108 "A gopher and gemini client."
109 :group 'applications)
111 ;; General appearance and customizations
113 (defcustom elpher-open-urls-with-eww nil
114 "If non-nil, open URL selectors using eww.
115 Otherwise, use the system browser via the BROWSE-URL function."
118 (defcustom elpher-use-header t
119 "If non-nil, display current page information in buffer header."
122 (defcustom elpher-auto-disengage-TLS nil
123 "If non-nil, automatically disengage TLS following an unsuccessful connection.
124 While enabling this may seem convenient, it is also potentially dangerous as it
125 allows switching from an encrypted channel back to plain text without user input."
128 (defcustom elpher-connection-timeout 5
129 "Specifies the number of seconds to wait for a network connection to time out."
132 (defcustom elpher-filter-ansi-from-text nil
133 "If non-nil, filter ANSI escape sequences from text.
134 The default behaviour is to use the ansi-color package to interpret these
138 (defcustom elpher-certificate-directory
139 (file-name-as-directory (locate-user-emacs-file "elpher-certificates"))
140 "Specify the name of the directory where client certificates will be stored.
141 These certificates may be used for establishing authenticated TLS connections."
144 (defcustom elpher-openssl-command "openssl"
145 "The command used to launch openssl when generating TLS client certificates."
148 (defcustom elpher-gemini-TLS-cert-checks nil
149 "If non-nil, verify gemini server TLS certs using the default security level.
150 Otherwise, certificate verification is disabled.
152 This defaults to off because it is standard practice for Gemini servers
153 to use self-signed certificates, meaning that most servers provide what
154 EMACS considers to be an invalid certificate."
157 (defcustom elpher-gemini-max-fill-width 80
158 "Specify the maximum default width (in columns) of text/gemini documents.
159 The actual width used is the minimum of this value and the window width at
160 the time when the text is rendered."
163 (defcustom elpher-gemini-link-string "→ "
164 "Specify the string used to indicate links when rendering gemini maps.
168 (defcustom elpher-gemini-bullet-string "•"
169 "Specify the string used for bullets when rendering gemini maps."
172 (defcustom elpher-bookmarks-file (locate-user-emacs-file "elpher-bookmarks")
173 "Specify the name of the file where elpher bookmarks will be saved."
176 (defcustom elpher-ipv4-always nil
177 "If non-nil, elpher will always use IPv4 to establish network connections.
178 This can be useful when browsing from a computer that supports IPv6, because
179 some servers which do not support IPv6 can take a long time to time-out."
182 (defcustom elpher-socks-always nil
183 "If non-nil, elpher will establish network connections over a SOCKS proxy.
184 Otherwise, the SOCKS proxy is only used for connections to onion services."
187 ;; Face customizations
189 (defgroup elpher-faces nil
190 "Elpher face customizations."
193 (defface elpher-index
194 '((t :inherit font-lock-keyword-face))
195 "Face used for directory type directory records.")
199 "Face used for text type directory records.")
202 '((t :inherit default))
203 "Face used for info type directory records.")
205 (defface elpher-image
206 '((t :inherit font-lock-string-face))
207 "Face used for image type directory records.")
209 (defface elpher-search
210 '((t :inherit warning))
211 "Face used for search type directory records.")
214 '((t :inherit font-lock-comment-face))
215 "Face used for html type directory records.")
217 (defface elpher-gemini
218 '((t :inherit font-lock-constant-face))
219 "Face used for Gemini type directory records.")
221 (defface elpher-other-url
222 '((t :inherit font-lock-comment-face))
223 "Face used for other URL type links records.")
225 (defface elpher-telnet
226 '((t :inherit font-lock-function-name-face))
227 "Face used for telnet type directory records.")
229 (defface elpher-binary
230 '((t :inherit font-lock-doc-face))
231 "Face used for binary type directory records.")
233 (defface elpher-unknown
234 '((t :inherit error))
235 "Face used for directory records with unknown/unsupported types.")
237 (defface elpher-margin-key
239 "Face used for directory margin key.")
241 (defface elpher-margin-brackets
242 '((t :inherit shadow))
243 "Face used for brackets around directory margin key.")
245 (defface elpher-gemini-heading1
246 '((t :inherit bold :height 1.8))
247 "Face used for gemini heading level 1.")
249 (defface elpher-gemini-heading2
250 '((t :inherit bold :height 1.5))
251 "Face used for gemini heading level 2.")
253 (defface elpher-gemini-heading3
254 '((t :inherit bold :height 1.2))
255 "Face used for gemini heading level 3.")
257 (defface elpher-gemini-preformatted
258 '((t :inherit fixed-pitch))
259 "Face used for pre-formatted gemini text blocks.")
261 (defface elpher-gemini-quoted
262 '((t :inherit font-lock-doc-face))
263 "Face used for gemini quoted texts.")
270 ;; An elpher "address" object is either a url object or a symbol.
271 ;; Symbol addresses are "special", corresponding to pages generated
272 ;; dynamically for and by elpher. All others represent pages which
273 ;; rely on content retrieved over the network.
275 (defun elpher-address-from-url (url-string)
276 "Create a ADDRESS object corresponding to the given URL-STRING."
277 (let ((data (match-data))) ; Prevent parsing clobbering match data
279 (let ((url (url-generic-parse-url url-string)))
280 (unless (and (not (url-fullness url)) (url-type url))
281 (setf (url-fullness url) t)
282 (setf (url-filename url)
283 (url-unhex-string (url-filename url)))
284 (unless (url-type url)
285 (setf (url-type url) "gopher"))
286 (when (or (equal "gopher" (url-type url))
287 (equal "gophers" (url-type url)))
289 (unless (url-host url)
290 (setf (url-host url) (url-filename url))
291 (setf (url-filename url) ""))
292 (when (or (equal (url-filename url) "")
293 (equal (url-filename url) "/"))
294 (setf (url-filename url) "/1")))
295 (when (equal "gemini" (url-type url))
297 (if (equal (url-filename url) "")
298 (setf (url-filename url) "/"))))
299 (elpher-remove-redundant-ports url))
300 (set-match-data data))))
302 (defun elpher-remove-redundant-ports (address)
303 "Remove redundant port specifiers from ADDRESS.
304 Here 'redundant' means that the specified port matches the default
305 for that protocol, eg 70 for gopher."
306 (if (and (not (elpher-address-special-p address))
307 (eq (url-portspec address) ; (url-port) is too slow!
308 (pcase (url-type address)
310 ((or "gopher" "gophers") 70)
313 (setf (url-portspec address) nil))
316 (defun elpher-make-gopher-address (type selector host port &optional tls)
317 "Create an ADDRESS object using gopher directory record attributes.
318 The basic attributes include: TYPE, SELECTOR, HOST and PORT.
319 If the optional attribute TLS is non-nil, the address will be marked as
320 requiring gopher-over-TLS."
322 ((equal type ?i) nil)
323 ((and (equal type ?h)
324 (string-prefix-p "URL:" selector))
325 (elpher-address-from-url (elt (split-string selector "URL:") 1)))
327 (elpher-address-from-url
330 ":" (number-to-string port))))
332 (elpher-address-from-url
333 (concat "gopher" (if tls "s" "")
335 ":" (number-to-string port)
339 (defun elpher-make-special-address (type)
340 "Create an ADDRESS object corresponding to the given special address symbol TYPE."
343 (defun elpher-address-to-url (address)
344 "Get string representation of ADDRESS, or nil if ADDRESS is special."
345 (if (elpher-address-special-p address)
347 (url-encode-url (url-recreate-url address))))
349 (defun elpher-address-type (address)
350 "Retrieve type of ADDRESS object.
351 This is used to determine how to retrieve and render the document the
352 address refers to, via the table `elpher-type-map'."
353 (if (symbolp address)
354 (list 'special address)
355 (let ((protocol (url-type address)))
356 (cond ((or (equal protocol "gopher")
357 (equal protocol "gophers"))
359 (if (member (url-filename address) '("" "/"))
361 (string-to-char (substring (url-filename address) 1)))))
362 ((equal protocol "gemini")
364 ((equal protocol "telnet")
366 ((equal protocol "finger")
370 (defun elpher-address-protocol (address)
371 "Retrieve the transport protocol for ADDRESS. This is nil for special addresses."
372 (if (symbolp address)
376 (defun elpher-address-filename (address)
377 "Retrieve the filename component of ADDRESS.
378 For gopher addresses this is a combination of the selector type and selector."
379 (if (symbolp address)
381 (url-filename address)))
383 (defun elpher-address-host (address)
384 "Retrieve host from ADDRESS object."
387 (defun elpher-address-user (address)
388 "Retrieve user from ADDRESS object."
391 (defun elpher-address-port (address)
392 "Retrieve port from ADDRESS object.
393 If no address is defined, returns 0. (This is for compatibility with the URL library.)"
394 (if (symbolp address)
398 (defun elpher-address-special-p (address)
399 "Return non-nil if ADDRESS object is special (e.g. start page, bookmarks page)."
402 (defun elpher-address-gopher-p (address)
403 "Return non-nill if ADDRESS object is a gopher address."
404 (and (not (elpher-address-special-p address))
405 (member (elpher-address-protocol address) '("gopher gophers"))))
407 (defun elpher-gopher-address-selector (address)
408 "Retrieve gopher selector from ADDRESS object."
409 (if (member (url-filename address) '("" "/"))
411 (url-unhex-string (substring (url-filename address) 2))))
416 (defvar elpher-content-cache (make-hash-table :test 'equal))
417 (defvar elpher-pos-cache (make-hash-table :test 'equal))
419 (defun elpher-get-cached-content (address)
420 "Retrieve the cached content for ADDRESS, or nil if none exists."
421 (gethash address elpher-content-cache))
423 (defun elpher-cache-content (address content)
424 "Set the content cache for ADDRESS to CONTENT."
425 (puthash address content elpher-content-cache))
427 (defun elpher-get-cached-pos (address)
428 "Retrieve the cached cursor position for ADDRESS, or nil if none exists."
429 (gethash address elpher-pos-cache))
431 (defun elpher-cache-pos (address pos)
432 "Set the cursor position cache for ADDRESS to POS."
433 (puthash address pos elpher-pos-cache))
438 (defun elpher-make-page (display-string address)
439 "Create a page with DISPLAY-STRING and ADDRESS."
440 (list display-string address))
442 (defun elpher-page-display-string (page)
443 "Retrieve the display string corresponding to PAGE."
446 (defun elpher-page-address (page)
447 "Retrieve the address corresponding to PAGE."
450 (defun elpher-page-set-address (page new-address)
451 "Set the address corresponding to PAGE to NEW-ADDRESS."
452 (setcar (cdr page) new-address))
454 (defvar elpher-current-page nil) ; buffer local
455 (defvar elpher-history nil) ; buffer local
457 (defun elpher-visit-page (page &optional renderer no-history)
458 "Visit PAGE using its own renderer or RENDERER, if non-nil.
459 Additionally, push PAGE onto the stack of previously-visited pages,
460 unless NO-HISTORY is non-nil."
462 (elpher-process-cleanup)
463 (unless (or no-history
464 (equal (elpher-page-address elpher-current-page)
465 (elpher-page-address page)))
466 (push elpher-current-page elpher-history))
467 (setq-local elpher-current-page page)
468 (let* ((address (elpher-page-address page))
469 (type (elpher-address-type address))
470 (type-record (cdr (assoc type elpher-type-map))))
472 (funcall (car type-record)
476 (elpher-visit-previous-page)
478 (`(gopher ,type-char)
479 (error "Unsupported gopher selector type '%c' for '%s'"
480 type-char (elpher-address-to-url address)))
482 (error "Unsupported address type '%S' for '%s'"
483 other (elpher-address-to-url address)))))))
485 (defun elpher-visit-previous-page ()
486 "Visit the previous page in the history."
487 (let ((previous-page (pop elpher-history)))
489 (elpher-visit-page previous-page nil t)
490 (error "No previous page"))))
492 (defun elpher-reload-current-page ()
493 "Reload the current page, discarding any existing cached content."
494 (elpher-cache-content (elpher-page-address elpher-current-page) nil)
495 (elpher-visit-page elpher-current-page))
497 (defun elpher-save-pos ()
498 "Save the current position of point to the current page."
499 (when elpher-current-page
500 (elpher-cache-pos (elpher-page-address elpher-current-page) (point))))
502 (defun elpher-restore-pos ()
503 "Restore the position of point to that cached in the current page."
504 (let ((pos (elpher-get-cached-pos (elpher-page-address elpher-current-page))))
507 (goto-char (point-min)))))
510 ;;; Buffer preparation
513 (defvar elpher-buffer-name "*elpher*"
514 "The default name of the Elpher buffer.")
516 (defun elpher-update-header ()
517 "If `elpher-use-header' is true, display current page info in window header."
518 (if elpher-use-header
519 (let* ((display-string (elpher-page-display-string elpher-current-page))
520 (address (elpher-page-address elpher-current-page))
521 (tls-string (if (and (not (elpher-address-special-p address))
522 (member (elpher-address-protocol address)
523 '("gophers" "gemini")))
526 (header (concat display-string
527 (propertize tls-string 'face 'bold))))
528 (setq header-line-format header))))
530 (defmacro elpher-with-clean-buffer (&rest args)
531 "Evaluate ARGS with a clean *elpher* buffer as current."
532 `(with-current-buffer elpher-buffer-name
533 (unless (eq major-mode 'elpher-mode)
534 ;; avoid resetting buffer-local variables
536 (let ((inhibit-read-only t))
537 (setq-local network-security-level
538 (default-value 'network-security-level))
540 (elpher-update-header)
543 (defun elpher-buffer-message (string &optional line)
544 "Replace first line in elpher buffer with STRING.
545 If LINE is non-nil, replace that line instead."
546 (with-current-buffer elpher-buffer-name
547 (let ((inhibit-read-only t))
548 (goto-char (point-min))
551 (let ((data (match-data)))
554 (re-search-forward "^.*$")
555 (replace-match string))
556 (set-match-data data))))))
562 (defvar elpher-user-coding-system nil
563 "User-specified coding system to use for decoding text responses.")
565 (defun elpher-decode (string)
566 "Decode STRING using autodetected or user-specified coding system."
567 (decode-coding-string string
568 (if elpher-user-coding-system
569 elpher-user-coding-system
570 (detect-coding-string string t))))
572 (defun elpher-preprocess-text-response (string)
573 "Preprocess text selector response contained in STRING.
574 This involes decoding the character representation, and clearing
575 away CRs and any terminating period."
576 (elpher-decode (replace-regexp-in-string "\n\.\n$" "\n"
577 (replace-regexp-in-string "\r" "" string))))
580 ;;; Network error reporting
583 (defun elpher-network-error (address error)
584 "Display ERROR message following unsuccessful negotiation with ADDRESS.
585 ERROR can be either an error object or a string."
586 (elpher-with-clean-buffer
587 (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
588 "When attempting to retrieve " (elpher-address-to-url address) ":\n"
589 (if (stringp error) error (error-message-string error)) "\n"
590 (propertize "\n----------------\n\n" 'face 'error)
591 "Press 'u' to return to the previous page.")))
594 ;;; General network communication
597 (defvar elpher-network-timer nil
598 "Timer used for network connections.")
600 (defvar elpher-use-tls nil
601 "If non-nil, use TLS to communicate with gopher servers.")
603 (defvar elpher-client-certificate nil
604 "If non-nil, contains client certificate details to use for TLS connections.")
606 (defun elpher-process-cleanup ()
607 "Immediately shut down any extant elpher process and timers."
608 (let ((p (get-process "elpher-process")))
609 (if p (delete-process p)))
610 (if (timerp elpher-network-timer)
611 (cancel-timer elpher-network-timer)))
613 (defun elpher-get-host-response (address default-port query-string response-processor
614 &optional use-tls force-ipv4)
615 "Generic function for retrieving data from ADDRESS.
617 When ADDRESS lacks a specific port, DEFAULT-PORT is used instead.
618 QUERY-STRING is a string sent to the host specified by ADDRESS to
619 illicet a response. This response is passed as an argument to the
620 function RESPONSE-PROCESSOR.
622 If non-nil, USE-TLS specifies that the connection is to be made over
623 TLS. If set to gemini, the certificate verification will be disabled
624 unless `elpher-gemini-TLS-cert-checks' is non-nil.
626 If non-nil, FORCE-IPV4 causes the network connection to be made over
627 ipv4 only. (The default behaviour when this is not set depends on
628 the host operating system and the local network capabilities."
629 (if (and use-tls (not (gnutls-available-p)))
630 (error "Use of TLS requires Emacs to be compiled with GNU TLS support")
631 (unless (< (elpher-address-port address) 65536)
632 (error "Cannot establish network connection: port number > 65536"))
633 (when (and (eq use-tls 'gemini) (not elpher-gemini-TLS-cert-checks))
634 (setq-local network-security-level 'low)
635 (setq-local gnutls-verify-error nil))
637 (let* ((kill-buffer-query-functions nil)
638 (port (elpher-address-port address))
639 (service (if (> port 0) port default-port))
640 (host (elpher-address-host address))
641 (socks (or elpher-socks-always (string-suffix-p ".onion" host)))
642 (response-string-parts nil)
645 (timer (run-at-time elpher-connection-timeout nil
647 (elpher-process-cleanup)
649 ; Try again with IPv4
650 ((not (or force-ipv4 socks))
651 (message "Connection timed out. Retrying with IPv4.")
652 (elpher-get-host-response address default-port
657 (not (eq use-tls 'gemini))
658 (or elpher-auto-disengage-TLS
660 "TLS connetion failed. Disable TLS mode and retry? ")))
661 (setq elpher-use-tls nil)
662 (elpher-get-host-response address default-port
667 (elpher-network-error address "Connection time-out."))))))
668 (gnutls-params (list :type 'gnutls-x509pki :hostname host
669 :keylist (elpher-get-current-keylist address)))
670 (proc (if socks (socks-open-network-stream "elpher-process" nil host service)
671 (make-network-process :name "elpher-process"
673 :family (and force-ipv4 'ipv4)
679 (cons 'gnutls-x509pki
680 (apply #'gnutls-boot-parameters
682 (setq elpher-network-timer timer)
683 (set-process-coding-system proc 'binary 'binary)
684 (set-process-query-on-exit-flag proc nil)
685 (elpher-buffer-message (concat "Connecting to " host "..."
686 " (press 'u' to abort)"))
687 (set-process-filter proc
688 (lambda (_proc string)
692 (setq bytes-received (+ bytes-received (length string)))
693 (let ((new-hkbytes-received (/ bytes-received 102400)))
694 (when (> new-hkbytes-received hkbytes-received)
695 (setq hkbytes-received new-hkbytes-received)
696 (elpher-buffer-message
698 (number-to-string (/ hkbytes-received 10.0))
701 (setq response-string-parts
702 (cons string response-string-parts))))
703 (set-process-sentinel proc
706 (cancel-timer timer))
707 (condition-case the-error
709 ((string-prefix-p "open" event) ; request URL
710 (elpher-buffer-message
711 (concat "Connected to " host ". Receiving data..."
712 " (press 'u' to abort)"))
713 (let ((inhibit-eol-conversion t))
714 (process-send-string proc query-string)))
715 ((string-prefix-p "deleted" event)) ; do nothing
716 ((and (not response-string-parts)
717 (not (or elpher-ipv4-always force-ipv4 socks)))
718 ; Try again with IPv4
719 (message "Connection failed. Retrying with IPv4.")
720 (elpher-get-host-response address default-port
724 (response-string-parts
725 (elpher-with-clean-buffer
726 (insert "Data received. Rendering..."))
727 (funcall response-processor
728 (apply #'concat (reverse response-string-parts)))
729 (elpher-restore-pos))
731 (error "No response from server")))
733 (elpher-network-error address the-error)))))
735 (if use-tls (apply #'gnutls-negotiate :process proc gnutls-params))
736 (funcall (process-sentinel proc) proc "open\n")))
738 (error "Error initiating connection to server")))))
741 ;;; Client-side TLS Certificate Management
744 (defun elpher-generate-certificate (common-name key-file cert-file &optional temporary)
745 "Generate a key and a self-signed client TLS certificate using openssl.
747 The Common Name field of the certificate is set to COMMON-NAME. The
748 arguments KEY-FILE and CERT-FILE should contain the absolute paths of
749 the key and certificate files to write.
751 If TEMPORARY is non-nil, the certificate will be given an exporation
752 period of one day, and the key and certificate files will be deleted
753 when the certificate is no longer needed for the current session.
755 Otherwise, the certificate will be given a 100 year expiration period
756 and the files will not be deleted.
758 The function returns a list containing the current host name, the
759 temporary flag, and the key and cert file names in the form required
760 by `gnutls-boot-parameters`."
761 (let ((exp-key-file (expand-file-name key-file))
762 (exp-cert-file (expand-file-name cert-file)))
765 (call-process elpher-openssl-command nil nil nil
766 "req" "-x509" "-newkey" "rsa:2048"
767 "-days" (if temporary "1" "36500")
769 "-subj" (concat "/CN=" common-name)
770 "-keyout" exp-key-file
771 "-out" exp-cert-file)
772 (list (elpher-address-host (elpher-page-address elpher-current-page))
773 temporary exp-key-file exp-cert-file))
775 (message "Check that openssl is installed, or customize `elpher-openssl-command`.")
776 (error "Program 'openssl', required for certificate generation, not found")))))
778 (defun elpher-generate-throwaway-certificate ()
779 "Generate and return details of a throwaway certificate.
780 The key and certificate files will be deleted when they are no
781 longer needed for this session."
782 (let* ((file-base (make-temp-name "elpher"))
783 (key-file (concat temporary-file-directory file-base ".key"))
784 (cert-file (concat temporary-file-directory file-base ".crt")))
785 (elpher-generate-certificate file-base key-file cert-file t)))
787 (defun elpher-generate-persistent-certificate (file-base common-name)
788 "Generate and return details of a persistent certificate.
789 The argument FILE-BASE is used as the base for the key and certificate
790 files, while COMMON-NAME specifies the common name field of the
793 The key and certificate files are written to in `elpher-certificate-directory'."
794 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
795 (cert-file (concat elpher-certificate-directory file-base ".crt")))
796 (elpher-generate-certificate common-name key-file cert-file)))
798 (defun elpher-get-existing-certificate (file-base)
799 "Return a certificate object corresponding to an existing certificate.
800 It is assumed that the key files FILE-BASE.key and FILE-BASE.crt exist in
801 the directory `elpher-certificate-directory'."
802 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
803 (cert-file (concat elpher-certificate-directory file-base ".crt")))
804 (list (elpher-address-host (elpher-page-address elpher-current-page))
806 (expand-file-name key-file)
807 (expand-file-name cert-file))))
809 (defun elpher-install-and-use-existing-certificate (key-file-src cert-file-src file-base)
810 "Install a key+certificate file pair in `elpher-certificate-directory'.
811 The strings KEY-FILE-SRC and CERT-FILE-SRC are the existing key and
812 certificate files to install. The argument FILE-BASE is used as the
813 base for the installed key and certificate files."
814 (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
815 (cert-file (concat elpher-certificate-directory file-base ".crt")))
816 (if (or (file-exists-p key-file)
817 (file-exists-p cert-file))
818 (error "A certificate with base name %s is already installed" file-base))
819 (copy-file key-file-src key-file)
820 (copy-file cert-file-src cert-file)
821 (list (elpher-address-host (elpher-page-address elpher-current-page))
823 (expand-file-name key-file)
824 (expand-file-name cert-file))))
826 (defun elpher-list-existing-certificates ()
827 "Return a list of the persistent certificates in `elpher-certificate-directory'."
828 (unless (file-directory-p elpher-certificate-directory)
829 (make-directory elpher-certificate-directory))
832 (file-name-sans-extension file))
833 (directory-files elpher-certificate-directory nil "\.key$")))
835 (defun elpher-forget-current-certificate ()
836 "Causes any current certificate to be forgotten.)
837 In the case of throwaway certificates, the key and certificate files
840 (when elpher-client-certificate
841 (unless (and (called-interactively-p 'any)
842 (not (y-or-n-p (concat "Really forget client certificate? "
843 "(Throwaway certificates will be deleted.)"))))
844 (when (cadr elpher-client-certificate)
845 (delete-file (elt elpher-client-certificate 2))
846 (delete-file (elt elpher-client-certificate 3)))
847 (setq elpher-client-certificate nil)
848 (if (called-interactively-p 'any)
849 (message "Client certificate forgotten.")))))
851 (defun elpher-get-current-keylist (address)
852 "Retrieve the `gnutls-boot-parameters'-compatable keylist.
854 This is obtained from the client certificate described by
855 `elpher-current-certificate', if one is available and the host for
856 that certificate matches the host in ADDRESS.
858 If `elpher-current-certificate' is non-nil, and its host name doesn't
859 match that of ADDRESS, the certificate is forgotten."
860 (if elpher-client-certificate
861 (if (string= (car elpher-client-certificate)
862 (elpher-address-host address))
863 (list (cddr elpher-client-certificate))
864 (elpher-forget-current-certificate)
865 (message "Disabling client certificate for new host")
870 ;;; Gopher selector retrieval
873 (defun elpher-get-gopher-response (address renderer)
874 "Get response string from gopher server at ADDRESS and render using RENDERER."
875 (elpher-get-host-response address 70
876 (concat (elpher-gopher-address-selector address) "\r\n")
878 (or (string= (elpher-address-protocol address) "gophers")
881 (defun elpher-get-gopher-page (renderer)
882 "Getter function for gopher pages.
883 The RENDERER procedure is used to display the contents of the page
884 once they are retrieved from the gopher server."
885 (let* ((address (elpher-page-address elpher-current-page))
886 (content (elpher-get-cached-content address)))
887 (if (and content (funcall renderer nil))
888 (elpher-with-clean-buffer
890 (elpher-restore-pos))
891 (elpher-with-clean-buffer
892 (insert "LOADING... (use 'u' to cancel)\n"))
893 (condition-case the-error
894 (elpher-get-gopher-response address renderer)
896 (elpher-network-error address the-error))))))
900 (defun elpher-insert-index (string)
901 "Insert the index corresponding to STRING into the current buffer."
902 ;; Should be able to split directly on CRLF, but some non-conformant
903 ;; LF-only servers sadly exist, hence the following.
904 (let ((str-processed (elpher-preprocess-text-response string)))
905 (dolist (line (split-string str-processed "\n"))
907 (unless (= (length line) 0)
908 (let* ((type (elt line 0))
909 (fields (split-string (substring line 1) "\t"))
910 (display-string (elt fields 0))
911 (selector (elt fields 1))
912 (host (elt fields 2))
913 (port (if (elt fields 3)
914 (string-to-number (elt fields 3))
916 (address (elpher-make-gopher-address type selector host port)))
917 (elpher-insert-index-record display-string address)))))))
919 (defun elpher-insert-margin (&optional type-name)
920 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
923 (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s")
925 (propertize "[" 'face 'elpher-margin-brackets)
926 (propertize type-name 'face 'elpher-margin-key)
927 (propertize "]" 'face 'elpher-margin-brackets))))
929 (insert (make-string elpher-margin-width ?\s))))
931 (defun elpher--page-button-help (_window buffer pos)
932 "Function called by Emacs to generate mouse-over text.
933 The arguments specify the BUFFER and the POS within the buffer of the item
934 for which help is required. The function returns the help to be
935 displayed. The _WINDOW argument is currently unused."
936 (with-current-buffer buffer
937 (let ((button (button-at pos)))
939 (let* ((page (button-get button 'elpher-page))
940 (address (elpher-page-address page)))
941 (format "mouse-1, RET: open '%s'" (if (elpher-address-special-p address)
943 (elpher-address-to-url address))))))))
945 (defun elpher-insert-index-record (display-string &optional address)
946 "Function to insert an index record into the current buffer.
947 The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
948 If ADDRESS is not supplied or nil the record is rendered as an
950 (let* ((type (if address (elpher-address-type address) nil))
951 (type-map-entry (cdr (assoc type elpher-type-map))))
953 (let* ((margin-code (elt type-map-entry 2))
954 (face (elt type-map-entry 3))
955 (filtered-display-string (ansi-color-filter-apply display-string))
956 (page (elpher-make-page filtered-display-string address)))
957 (elpher-insert-margin margin-code)
958 (insert-text-button filtered-display-string
961 'action #'elpher-click-link
963 'help-echo #'elpher--page-button-help))
966 (elpher-insert-margin)
967 (let ((propertized-display-string
968 (propertize display-string 'face 'elpher-info)))
969 (insert (elpher-process-text-for-display propertized-display-string))))
970 (`(gopher ,selector-type) ;; Unknown
971 (elpher-insert-margin (concat (char-to-string selector-type) "?"))
972 (insert (propertize display-string
973 'face 'elpher-unknown)))))
976 (defun elpher-click-link (button)
977 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
978 (let ((page (button-get button 'elpher-page)))
979 (elpher-visit-page page)))
981 (defun elpher-render-index (data &optional _mime-type-string)
982 "Render DATA as an index. MIME-TYPE-STRING is unused."
983 (elpher-with-clean-buffer
986 (elpher-insert-index data)
987 (elpher-cache-content (elpher-page-address elpher-current-page)
992 (defconst elpher-url-regex
993 "\\([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\-_~?/@|#]\\)?\\)?"
994 "Regexp used to locate and buttinofy URLs in text files loaded by elpher.")
996 (defun elpher-buttonify-urls (string)
997 "Turn substrings which look like urls in STRING into clickable buttons."
1000 (goto-char (point-min))
1001 (while (re-search-forward elpher-url-regex nil t)
1002 (let ((page (elpher-make-page (substring-no-properties (match-string 0))
1003 (elpher-address-from-url (match-string 0)))))
1004 (make-text-button (match-beginning 0)
1007 'action #'elpher-click-link
1009 'help-echo #'elpher--page-button-help
1013 (defconst elpher-ansi-regex "\x1b\\[[^m]*m"
1014 "Wildly incomplete regexp used to strip out some troublesome ANSI escape sequences.")
1016 (defun elpher-process-text-for-display (string)
1017 "Perform any desired processing of STRING prior to display as text.
1018 Currently includes buttonifying URLs and processing ANSI escape codes."
1019 (elpher-buttonify-urls (if elpher-filter-ansi-from-text
1020 (ansi-color-filter-apply string)
1021 (ansi-color-apply string))))
1023 (defun elpher-render-text (data &optional _mime-type-string)
1024 "Render DATA as text. MIME-TYPE-STRING is unused."
1025 (elpher-with-clean-buffer
1028 (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
1029 (elpher-cache-content
1030 (elpher-page-address elpher-current-page)
1035 (defun elpher-render-image (data &optional _mime-type-string)
1036 "Display DATA as image. MIME-TYPE-STRING is unused."
1039 (if (display-images-p)
1041 (let ((image (create-image
1044 (elpher-with-clean-buffer
1045 (insert-image image)
1046 (elpher-restore-pos))))
1047 (elpher-render-download data))))
1049 ;; Search retrieval and rendering
1051 (defun elpher-get-gopher-query-page (renderer)
1052 "Getter for gopher addresses requiring input.
1053 The response is rendered using the rendering function RENDERER."
1054 (let* ((address (elpher-page-address elpher-current-page))
1055 (content (elpher-get-cached-content address))
1057 (if (and content (funcall renderer nil))
1058 (elpher-with-clean-buffer
1060 (elpher-restore-pos)
1061 (message "Displaying cached search results. Reload to perform a new search."))
1063 (let* ((query-string (read-string "Query: "))
1064 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
1065 (search-address (elpher-make-gopher-address ?1
1067 (elpher-address-host address)
1068 (elpher-address-port address)
1069 (equal (elpher-address-type address) "gophers"))))
1072 (elpher-with-clean-buffer
1073 (insert "LOADING RESULTS... (use 'u' to cancel)"))
1074 (elpher-get-gopher-response search-address renderer))
1076 (elpher-visit-previous-page))))))
1078 ;; Raw server response rendering
1080 (defun elpher-render-raw (data &optional mime-type-string)
1081 "Display raw DATA in buffer. MIME-TYPE-STRING is also displayed if provided."
1084 (elpher-with-clean-buffer
1085 (when mime-type-string
1086 (insert "MIME type specified by server: '" mime-type-string "'\n"))
1088 (goto-char (point-min)))
1089 (message "Displaying raw server response. Reload or redraw to return to standard view.")))
1091 ;; File save "rendering"
1093 (defun elpher-render-download (data &optional _mime-type-string)
1094 "Save DATA to file. MIME-TYPE-STRING is unused."
1097 (let* ((address (elpher-page-address elpher-current-page))
1098 (selector (if (elpher-address-gopher-p address)
1099 (elpher-gopher-address-selector address)
1100 (elpher-address-filename address))))
1101 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1102 (let* ((filename-proposal (file-name-nondirectory selector))
1103 (filename (read-file-name "Download complete. Save file as: "
1105 (if (> (length filename-proposal) 0)
1108 (let ((coding-system-for-write 'binary))
1109 (with-temp-file filename
1111 (message (format "Saved to file %s." filename))))))
1115 (defun elpher-render-html (data &optional _mime-type-string)
1116 "Render DATA as HTML using shr. MIME-TYPE-STRING is unused."
1117 (elpher-with-clean-buffer
1120 (let ((dom (with-temp-buffer
1122 (libxml-parse-html-region (point-min) (point-max)))))
1123 (shr-insert-document dom)))))
1125 ;; Gemini page retrieval
1127 (defvar elpher-gemini-redirect-chain)
1129 (defun elpher-get-gemini-response (address renderer)
1130 "Get response string from gemini server at ADDRESS and render using RENDERER."
1131 (elpher-get-host-response address 1965
1132 (concat (elpher-address-to-url address) "\r\n")
1133 (lambda (response-string)
1134 (elpher-process-gemini-response response-string renderer))
1137 (defun elpher-parse-gemini-response (response)
1138 "Parse the RESPONSE string and return a list of components.
1139 The list is of the form (code meta body). A response of nil implies
1140 that the response was malformed."
1141 (let ((header-end-idx (string-match "\r\n" response)))
1143 (let ((header (string-trim (substring response 0 header-end-idx)))
1144 (body (substring response (+ header-end-idx 2))))
1145 (if (>= (length header) 2)
1146 (let ((code (substring header 0 2))
1147 (meta (string-trim (substring header 2))))
1148 (list code meta body))
1149 (error "Malformed response: No response status found in header %s" header)))
1150 (error "Malformed response: No CRLF-delimited header found in response %s" response))))
1152 (defun elpher-process-gemini-response (response-string renderer)
1153 "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
1154 (let ((response-components (elpher-parse-gemini-response response-string)))
1155 (let ((response-code (elt response-components 0))
1156 (response-meta (elt response-components 1))
1157 (response-body (elt response-components 2)))
1158 (pcase (elt response-code 0)
1159 (?1 ; Input required
1160 (elpher-with-clean-buffer
1161 (insert "Gemini server is requesting input."))
1162 (let* ((query-string
1163 (if (eq (elt response-code 1) ?1)
1164 (read-passwd (concat response-meta ": "))
1165 (read-string (concat response-meta ": "))))
1166 (query-address (seq-copy (elpher-page-address elpher-current-page)))
1167 (old-fname (url-filename query-address)))
1168 (setf (url-filename query-address)
1169 (concat old-fname "?" (url-build-query-string `((,query-string)))))
1170 (elpher-get-gemini-response query-address renderer)))
1171 (?2 ; Normal response
1172 (funcall renderer response-body response-meta))
1174 (message "Following redirect to %s" response-meta)
1175 (if (>= (length elpher-gemini-redirect-chain) 5)
1176 (error "More than 5 consecutive redirects followed"))
1177 (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
1178 (if (member redirect-address elpher-gemini-redirect-chain)
1179 (error "Redirect loop detected"))
1180 (if (not (string= (elpher-address-protocol redirect-address)
1182 (error "Server tried to automatically redirect to non-gemini URL: %s"
1184 (elpher-page-set-address elpher-current-page redirect-address)
1185 (add-to-list 'elpher-gemini-redirect-chain redirect-address)
1186 (elpher-get-gemini-response redirect-address renderer)))
1187 (?4 ; Temporary failure
1188 (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
1189 response-code response-meta))
1190 (?5 ; Permanent failure
1191 (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
1192 response-code response-meta))
1193 (?6 ; Client certificate required
1194 (elpher-with-clean-buffer
1195 (if elpher-client-certificate
1196 (insert "Gemini server does not recognise the provided TLS certificate:\n\n")
1197 (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
1199 (elpher-gemini-insert-text response-meta))
1200 (let ((chosen-certificate (elpher-choose-client-certificate)))
1201 (unless chosen-certificate
1202 (error "Gemini server requires a client certificate and none was provided"))
1203 (setq elpher-client-certificate chosen-certificate))
1204 (elpher-with-clean-buffer)
1205 (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer))
1207 (error "Gemini server response unknown: %s %s"
1208 response-code response-meta))))))
1210 (defun elpher-choose-client-certificate ()
1211 "Prompt for a client certificate to use to establish a TLS connection."
1212 (let* ((read-answer-short t))
1213 (pcase (read-answer "What do you want to do? "
1215 "generate and use throw-away certificate")
1217 "generate new or use existing persistent certificate")
1219 "stop immediately")))
1221 (setq elpher-client-certificate (elpher-generate-throwaway-certificate)))
1223 (let* ((existing-certificates (elpher-list-existing-certificates))
1224 (file-base (completing-read
1225 "Nickname for new or existing certificate (autocompletes, empty response aborts): "
1226 existing-certificates)))
1227 (if (string-empty-p (string-trim file-base))
1229 (if (member file-base existing-certificates)
1230 (setq elpher-client-certificate
1231 (elpher-get-existing-certificate file-base))
1232 (pcase (read-answer "Generate new certificate or install externally-generated one? "
1234 "generate new certificate")
1236 "install existing certificate")
1238 "stop immediately")))
1240 (let ((common-name (read-string "Common Name field for new certificate: "
1242 (message "New key and self-signed certificate written to %s"
1243 elpher-certificate-directory)
1244 (elpher-generate-persistent-certificate file-base common-name)))
1246 (let* ((cert-file (read-file-name "Certificate file: " nil nil t))
1247 (key-file (read-file-name "Key file: " nil nil t)))
1248 (message "Key and certificate installed in %s for future use"
1249 elpher-certificate-directory)
1250 (elpher-install-and-use-existing-certificate key-file
1256 (defun elpher-get-gemini-page (renderer)
1257 "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
1258 (let* ((address (elpher-page-address elpher-current-page))
1259 (content (elpher-get-cached-content address)))
1260 (condition-case the-error
1261 (if (and content (funcall renderer nil))
1262 (elpher-with-clean-buffer
1264 (elpher-restore-pos))
1265 (elpher-with-clean-buffer
1266 (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
1267 (setq elpher-gemini-redirect-chain nil)
1268 (elpher-get-gemini-response address renderer))
1270 (elpher-network-error address the-error)))))
1272 (defun elpher-render-gemini (body &optional mime-type-string)
1273 "Render gemini response BODY with rendering MIME-TYPE-STRING."
1276 (let* ((mime-type-string* (if (or (not mime-type-string)
1277 (string-empty-p mime-type-string))
1278 "text/gemini; charset=utf-8"
1280 (mime-type-split (split-string mime-type-string* ";" t))
1281 (mime-type (string-trim (car mime-type-split)))
1282 (parameters (mapcar (lambda (s)
1283 (let ((key-val (split-string s "=")))
1284 (list (downcase (string-trim (car key-val)))
1285 (downcase (string-trim (cadr key-val))))))
1286 (cdr mime-type-split))))
1287 (when (string-prefix-p "text/" mime-type)
1288 (setq body (decode-coding-string
1290 (if (assoc "charset" parameters)
1291 (intern (cadr (assoc "charset" parameters)))
1293 (setq body (replace-regexp-in-string "\r" "" body)))
1295 ((or "text/gemini" "")
1296 (elpher-render-gemini-map body parameters))
1298 (elpher-render-html body))
1299 ((pred (string-prefix-p "text/"))
1300 (elpher-render-gemini-plain-text body parameters))
1301 ((pred (string-prefix-p "image/"))
1302 (elpher-render-image body))
1304 (elpher-render-download body))))))
1306 (defun elpher-gemini-get-link-url (link-line)
1307 "Extract the url portion of LINK-LINE, a gemini map file link line.
1308 Returns nil in the event that the contents of the line following the
1309 => prefix are empty."
1310 (let ((l (split-string (substring link-line 2))))
1312 (string-trim (elt l 0))
1315 (defun elpher-gemini-get-link-display-string (link-line)
1316 "Extract the display string portion of LINK-LINE, a gemini map file link line.
1317 Returns the url portion in the event that the display-string portion is empty."
1318 (let* ((rest (string-trim (elt (split-string link-line "=>") 1)))
1319 (idx (string-match "[ \t]" rest)))
1320 (string-trim (if idx
1321 (substring rest (+ idx 1))
1324 (defun elpher-collapse-dot-sequences (filename)
1325 "Collapse dot sequences in FILENAME.
1326 For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
1327 (let* ((path (split-string filename "/"))
1328 (path-reversed-normalized
1329 (seq-reduce (lambda (a b)
1330 (cond ((and a (equal b "..") (cdr a)))
1331 ((and (not a) (equal b "..")) a) ;leading .. are dropped
1335 (string-join (reverse path-reversed-normalized) "/")))
1337 (defun elpher-address-from-gemini-url (url)
1338 "Extract address from URL with defaults as per gemini map files.
1339 While there's obviously some redundancy here between this function and
1340 `elpher-address-from-url', gemini map file URLs require enough special
1341 treatment that a separate function is warranted."
1342 (let ((address (url-generic-parse-url url))
1343 (current-address (elpher-page-address elpher-current-page)))
1344 (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
1345 (setf (url-fullness address) t)
1346 (if (url-host address) ;if there is an explicit host, filenames are absolute
1347 (if (string-empty-p (url-filename address))
1348 (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
1349 (setf (url-host address) (url-host current-address))
1350 (setf (url-port address) (url-port current-address))
1351 (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
1352 (setf (url-filename address)
1353 (concat (file-name-directory (url-filename current-address))
1354 (url-filename address)))))
1355 (unless (url-type address)
1356 (setf (url-type address) "gemini"))
1357 (when (equal (url-type address) "gemini")
1358 (setf (url-filename address)
1359 (elpher-collapse-dot-sequences (url-filename address)))))
1360 (elpher-remove-redundant-ports address)))
1362 (defun elpher-gemini-insert-link (link-line)
1363 "Insert link described by LINK-LINE into a text/gemini document."
1364 (let* ((url (elpher-gemini-get-link-url link-line))
1365 (display-string (elpher-gemini-get-link-display-string link-line))
1366 (address (elpher-address-from-gemini-url url))
1367 (type (if address (elpher-address-type address) nil))
1368 (type-map-entry (cdr (assoc type elpher-type-map))))
1369 (when display-string
1370 (insert elpher-gemini-link-string)
1372 (let* ((face (elt type-map-entry 3))
1373 (filtered-display-string (ansi-color-filter-apply display-string))
1374 (page (elpher-make-page filtered-display-string address)))
1375 (insert-text-button filtered-display-string
1378 'action #'elpher-click-link
1380 'help-echo #'elpher--page-button-help))
1381 (insert (propertize display-string 'face 'elpher-unknown)))
1384 (defun elpher-gemini-insert-header (header-line)
1385 "Insert header described by HEADER-LINE into a text/gemini document.
1386 The gemini map file line describing the header is given
1388 (when (string-match "^\\(#+\\)[ \t]*" header-line)
1389 (let* ((level (length (match-string 1 header-line)))
1390 (header (substring header-line (match-end 0)))
1392 (1 'elpher-gemini-heading1)
1393 (2 'elpher-gemini-heading2)
1394 (3 'elpher-gemini-heading3)
1396 (unless (display-graphic-p)
1397 (insert (make-string level ?#) " "))
1398 (insert (propertize header 'face face))
1401 (defun elpher-gemini-insert-text (text-line)
1402 "Insert a plain non-preformatted TEXT-LINE into a text/gemini document.
1403 This function uses Emacs' auto-fill to wrap text sensibly to a maximum
1404 width defined by elpher-gemini-max-fill-width."
1405 (string-match "\\(^[ \t]*\\)\\(\*[ \t]+\\|>[ \t]*\\)?" text-line)
1406 (let* ((line-prefix (match-string 2 text-line))
1407 (processed-text-line
1409 (cond ((string-prefix-p "*" line-prefix)
1411 (replace-regexp-in-string "\*"
1412 elpher-gemini-bullet-string
1413 (match-string 0 text-line))
1414 (substring text-line (match-end 0))))
1415 ((string-prefix-p ">" line-prefix)
1416 (propertize text-line 'face 'elpher-gemini-quoted))
1419 (adaptive-fill-mode nil))
1420 (insert (elpher-process-text-for-display processed-text-line))
1423 (defun elpher-render-gemini-map (data _parameters)
1424 "Render DATA as a gemini map file, PARAMETERS is currently unused."
1425 (elpher-with-clean-buffer
1426 (let ((preformatted nil))
1428 (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))
1429 (dolist (line (split-string data "\n"))
1431 ((string-prefix-p "```" line) (setq preformatted (not preformatted)))
1432 (preformatted (insert (elpher-process-text-for-display
1433 (propertize line 'face 'elpher-gemini-preformatted))
1435 ((string-prefix-p "=>" line) (elpher-gemini-insert-link line))
1436 ((string-prefix-p "#" line) (elpher-gemini-insert-header line))
1437 (t (elpher-gemini-insert-text line)))))
1438 (elpher-cache-content
1439 (elpher-page-address elpher-current-page)
1442 (defun elpher-render-gemini-plain-text (data _parameters)
1443 "Render DATA as plain text file. PARAMETERS is currently unused."
1444 (elpher-with-clean-buffer
1445 (insert (elpher-process-text-for-display data))
1446 (elpher-cache-content
1447 (elpher-page-address elpher-current-page)
1451 ;; Finger page connection
1453 (defun elpher-get-finger-page (renderer)
1454 "Opens a finger connection to the current page address.
1455 The result is rendered using RENDERER."
1456 (let* ((address (elpher-page-address elpher-current-page))
1457 (content (elpher-get-cached-content address)))
1458 (if (and content (funcall renderer nil))
1459 (elpher-with-clean-buffer
1461 (elpher-restore-pos))
1462 (elpher-with-clean-buffer
1463 (insert "LOADING... (use 'u' to cancel)\n"))
1464 (condition-case the-error
1465 (let* ((kill-buffer-query-functions nil)
1466 (user (let ((filename (elpher-address-filename address)))
1467 (if (> (length filename) 1)
1468 (substring filename 1)
1469 (elpher-address-user address)))))
1470 (elpher-get-host-response address 79
1471 (concat user "\r\n")
1474 (elpher-network-error address the-error))))))
1477 ;; Telnet page connection
1479 (defun elpher-get-telnet-page (renderer)
1480 "Opens a telnet connection to the current page address (RENDERER must be nil)."
1482 (elpher-visit-previous-page)
1483 (error "Command not supported for telnet URLs"))
1484 (let* ((address (elpher-page-address elpher-current-page))
1485 (host (elpher-address-host address))
1486 (port (elpher-address-port address)))
1487 (elpher-visit-previous-page)
1493 ;; Other URL page opening
1495 (defun elpher-get-other-url-page (renderer)
1496 "Getter which attempts to open the URL specified by the current page (RENDERER must be nil)."
1498 (elpher-visit-previous-page)
1499 (error "Command not supported for general URLs"))
1500 (let* ((address (elpher-page-address elpher-current-page))
1501 (url (elpher-address-to-url address)))
1503 (elpher-visit-previous-page) ; Do first in case of non-local exits.
1504 (message "Opening URL...")
1505 (if elpher-open-urls-with-eww
1507 (browse-url url)))))
1510 ;; Start page page retrieval
1512 (defun elpher-get-start-page (renderer)
1513 "Getter which displays the start page (RENDERER must be nil)."
1515 (elpher-visit-previous-page)
1516 (error "Command not supported for start page"))
1517 (elpher-with-clean-buffer
1518 (insert " --------------------------------------------\n"
1519 " Elpher Gopher and Gemini Client \n"
1520 " version " elpher-version "\n"
1521 " --------------------------------------------\n"
1523 "Default bindings:\n"
1525 " - TAB/Shift-TAB: next/prev item on current page\n"
1526 " - RET/mouse-1: open item under cursor\n"
1527 " - m: select an item on current page by name (autocompletes)\n"
1528 " - u/mouse-3/U: return to previous page or to the start page\n"
1529 " - o/O: visit different selector or the root menu of the current server\n"
1530 " - g: go to a particular address (gopher, gemini, finger)\n"
1531 " - d/D: download item under cursor or current page\n"
1532 " - i/I: info on item under cursor or current page\n"
1533 " - c/C: copy URL representation of item under cursor or current page\n"
1534 " - a/A: bookmark the item under cursor or current page\n"
1535 " - x/X: remove bookmark for item under cursor or current page\n"
1536 " - B: visit the bookmarks page\n"
1537 " - r: redraw current page (using cached contents if available)\n"
1538 " - R: reload current page (regenerates cache)\n"
1539 " - S: set character coding system for gopher (default is to autodetect)\n"
1540 " - T: toggle TLS gopher mode\n"
1541 " - F: forget/discard current TLS client certificate\n"
1542 " - .: display the raw server response for the current page\n"
1544 "Start your exploration of gopher space and gemini:\n")
1545 (elpher-insert-index-record "Floodgap Systems Gopher Server"
1546 (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
1547 (elpher-insert-index-record "Project Gemini home page"
1548 (elpher-address-from-url "gemini://gemini.circumlunar.space/"))
1550 "Alternatively, select a search engine and enter some search terms:\n")
1551 (elpher-insert-index-record "Gopher Search Engine (Veronica-2)"
1552 (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
1553 (elpher-insert-index-record "Gemini Search Engine (GUS)"
1554 (elpher-address-from-url "gemini://gus.guru/search"))
1556 "This page contains your bookmarked sites (also visit with B):\n")
1557 (elpher-insert-index-record "Your Bookmarks" 'bookmarks)
1559 "For Elpher release news or to leave feedback, visit:\n")
1560 (elpher-insert-index-record "The Elpher Project Page"
1561 (elpher-make-gopher-address ?1
1567 (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
1568 (insert-text-button "Elpher info manual"
1574 'help-echo help-string))
1575 (insert " for the full documentation. **\n")
1577 (concat " (This should be available if you have installed Elpher using\n"
1578 " MELPA. Otherwise you will have to install the manual yourself.)\n")
1580 (elpher-restore-pos)))
1582 ;; Bookmarks page page retrieval
1584 (defun elpher-get-bookmarks-page (renderer)
1585 "Getter to load and display the current bookmark list (RENDERER must be nil)."
1587 (elpher-visit-previous-page)
1588 (error "Command not supported for bookmarks page"))
1589 (elpher-with-clean-buffer
1590 (insert "---- Bookmark list ----\n\n")
1591 (let ((bookmarks (elpher-load-bookmarks)))
1593 (dolist (bookmark bookmarks)
1594 (let ((display-string (elpher-bookmark-display-string bookmark))
1595 (address (elpher-address-from-url (elpher-bookmark-url bookmark))))
1596 (elpher-insert-index-record display-string address)))
1597 (insert "No bookmarks found.\n")))
1598 (insert "\n-----------------------\n"
1600 "- u: return to previous page\n"
1601 "- x: delete selected bookmark\n"
1602 "- a: rename selected bookmark\n"
1604 "Bookmarks are stored in the file ")
1605 (let ((filename elpher-bookmarks-file)
1606 (help-string "RET,mouse-1: Open bookmarks file in new buffer for editing."))
1607 (insert-text-button filename
1611 (find-file filename))
1613 'help-echo help-string))
1615 (elpher-restore-pos)))
1621 (defun elpher-make-bookmark (display-string url)
1622 "Make an elpher bookmark.
1623 DISPLAY-STRING determines how the bookmark will appear in the
1624 bookmark list, while URL is the url of the entry."
1625 (list display-string url))
1627 (defun elpher-bookmark-display-string (bookmark)
1628 "Get the display string of BOOKMARK."
1631 (defun elpher-set-bookmark-display-string (bookmark display-string)
1632 "Set the display string of BOOKMARK to DISPLAY-STRING."
1633 (setcar bookmark display-string))
1635 (defun elpher-bookmark-url (bookmark)
1636 "Get the address for BOOKMARK."
1639 (defun elpher-save-bookmarks (bookmarks)
1640 "Record the bookmark list BOOKMARKS to the user's bookmark file.
1641 Beware that this completely replaces the existing contents of the file."
1642 (let ((bookmark-dir (file-name-directory elpher-bookmarks-file)))
1643 (unless (file-directory-p bookmark-dir)
1644 (make-directory bookmark-dir)))
1645 (with-temp-file elpher-bookmarks-file
1647 (insert "; Elpher bookmarks file\n\n"
1648 "; Bookmarks are stored as a list of (label URL) items.\n"
1649 "; Feel free to edit by hand, but take care to ensure\n"
1650 "; the list structure remains intact.\n\n")
1651 (pp bookmarks (current-buffer))))
1653 (defun elpher-load-bookmarks ()
1654 "Get the list of bookmarks from the users's bookmark file."
1658 (insert-file-contents elpher-bookmarks-file)
1659 (goto-char (point-min))
1660 (read (current-buffer))))))
1661 (if (and bookmarks (listp (cadar bookmarks)))
1663 (message "Reading old bookmark file. (Will be updated on write.)")
1664 (mapcar (lambda (old-bm)
1666 (elpher-address-to-url (apply #'elpher-make-gopher-address
1671 (defun elpher-add-address-bookmark (address display-string)
1672 "Save a bookmark for ADDRESS with label DISPLAY-STRING.)))
1673 If ADDRESS is already bookmarked, update the label only."
1674 (let ((bookmarks (elpher-load-bookmarks))
1675 (url (elpher-address-to-url address)))
1676 (let ((existing-bookmark (rassoc (list url) bookmarks)))
1677 (if existing-bookmark
1678 (elpher-set-bookmark-display-string existing-bookmark display-string)
1679 (push (elpher-make-bookmark display-string url) bookmarks)))
1680 (elpher-save-bookmarks bookmarks)))
1682 (defun elpher-remove-address-bookmark (address)
1683 "Remove any bookmark to ADDRESS."
1684 (let ((url (elpher-address-to-url address)))
1685 (elpher-save-bookmarks
1686 (seq-filter (lambda (bookmark)
1687 (not (equal (elpher-bookmark-url bookmark) url)))
1688 (elpher-load-bookmarks)))))
1690 ;;; Interactive procedures
1693 (defun elpher-next-link ()
1694 "Move point to the next link on the current page."
1698 (defun elpher-prev-link ()
1699 "Move point to the previous link on the current page."
1701 (backward-button 1))
1703 (defun elpher-follow-current-link ()
1704 "Open the link or url at point."
1709 (defun elpher-go (host-or-url)
1710 "Go to a particular gopher site HOST-OR-URL.
1711 When run interactively HOST-OR-URL is read from the minibuffer."
1712 (interactive "sGopher or Gemini URL: ")
1713 (let* ((cleaned-host-or-url (string-trim host-or-url))
1714 (address (elpher-address-from-url cleaned-host-or-url))
1715 (page (elpher-make-page cleaned-host-or-url address)))
1716 (switch-to-buffer elpher-buffer-name)
1717 (elpher-visit-page page)
1720 (defun elpher-go-current ()
1721 "Go to a particular site read from the minibuffer, initialized with the current URL."
1723 (let ((address (elpher-page-address elpher-current-page)))
1724 (if (elpher-address-special-p address)
1725 (error "Command invalid for this page")
1726 (let ((url (read-string "Gopher or Gemini URL: " (elpher-address-to-url address))))
1727 (elpher-visit-page (elpher-make-page url (elpher-address-from-url url)))))))
1729 (defun elpher-redraw ()
1730 "Redraw current page."
1732 (elpher-visit-page elpher-current-page))
1734 (defun elpher-reload ()
1735 "Reload current page."
1737 (elpher-reload-current-page))
1739 (defun elpher-toggle-tls ()
1740 "Toggle TLS encryption mode for gopher."
1742 (setq elpher-use-tls (not elpher-use-tls))
1744 (if (gnutls-available-p)
1745 (message "TLS gopher mode enabled. (Will not affect current page until reload.)")
1746 (setq elpher-use-tls nil)
1747 (error "Cannot enable TLS gopher mode: GnuTLS not available"))
1748 (message "TLS gopher mode disabled. (Will not affect current page until reload.)")))
1750 (defun elpher-view-raw ()
1751 "View raw server response for current page."
1753 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
1754 (error "This page was not generated by a server")
1755 (elpher-visit-page elpher-current-page
1756 #'elpher-render-raw)))
1758 (defun elpher-back ()
1759 "Go to previous site."
1761 (elpher-visit-previous-page))
1763 (defun elpher-back-to-start ()
1764 "Go all the way back to the start page."
1766 (setq-local elpher-current-page nil)
1767 (setq-local elpher-history nil)
1768 (let ((start-page (elpher-make-page "Elpher Start Page"
1769 (elpher-make-special-address 'start))))
1770 (elpher-visit-page start-page)))
1772 (defun elpher-download ()
1773 "Download the link at point."
1775 (let ((button (button-at (point))))
1777 (let ((page (button-get button 'elpher-page)))
1778 (if (elpher-address-special-p (elpher-page-address page))
1779 (error "Cannot download %s"
1780 (elpher-page-display-string page))
1781 (elpher-visit-page (button-get button 'elpher-page)
1782 #'elpher-render-download)))
1783 (error "No link selected"))))
1785 (defun elpher-download-current ()
1786 "Download the current page."
1788 (if (elpher-address-special-p (elpher-page-address elpher-current-page))
1789 (error "Cannot download %s"
1790 (elpher-page-display-string elpher-current-page))
1791 (elpher-visit-page (elpher-make-page
1792 (elpher-page-display-string elpher-current-page)
1793 (elpher-page-address elpher-current-page))
1794 #'elpher-render-download
1797 (defun elpher-build-link-map ()
1798 "Build alist mapping link names to destination pages in current buffer."
1799 (let ((link-map nil)
1800 (b (next-button (point-min) t)))
1802 (push (cons (button-label b) b) link-map)
1803 (setq b (next-button (button-start b))))
1806 (defun elpher-jump ()
1807 "Select a directory entry by name. Similar to the info browser (m)enu command."
1809 (let* ((link-map (elpher-build-link-map)))
1811 (let ((key (let ((completion-ignore-case t))
1812 (completing-read "Directory item/link: "
1814 (if (and key (> (length key) 0))
1815 (let ((b (cdr (assoc key link-map))))
1816 (goto-char (button-start b))
1817 (button-activate b)))))))
1819 (defun elpher-root-dir ()
1820 "Visit root of current server."
1822 (let ((address (elpher-page-address elpher-current-page)))
1823 (if (not (elpher-address-special-p address))
1824 (if (or (member (url-filename address) '("/" ""))
1825 (and (elpher-address-gopher-p address)
1826 (= (length (elpher-gopher-address-selector address)) 0)))
1827 (error "Already at root directory of current server")
1828 (let ((address-copy (elpher-address-from-url
1829 (elpher-address-to-url address))))
1830 (setf (url-filename address-copy) "")
1831 (elpher-go (elpher-address-to-url address-copy))))
1832 (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
1834 (defun elpher-bookmarks-current-p ()
1835 "Return non-nil if current page is a bookmarks page."
1836 (equal (elpher-address-type (elpher-page-address elpher-current-page))
1837 '(special bookmarks)))
1839 (defun elpher-reload-bookmarks ()
1840 "Reload bookmarks if current page is a bookmarks page."
1841 (if (elpher-bookmarks-current-p)
1842 (elpher-reload-current-page)))
1844 (defun elpher-bookmark-current ()
1845 "Bookmark the current page."
1847 (let ((address (elpher-page-address elpher-current-page))
1848 (display-string (elpher-page-display-string elpher-current-page)))
1849 (if (not (elpher-address-special-p address))
1850 (let ((bookmark-display-string (read-string "Bookmark display string: "
1852 (elpher-add-address-bookmark address bookmark-display-string)
1853 (message "Bookmark added."))
1854 (error "Cannot bookmark %s" display-string))))
1856 (defun elpher-bookmark-link ()
1857 "Bookmark the link at point."
1859 (let ((button (button-at (point))))
1861 (let* ((page (button-get button 'elpher-page))
1862 (address (elpher-page-address page))
1863 (display-string (elpher-page-display-string page)))
1864 (if (not (elpher-address-special-p address))
1865 (let ((bookmark-display-string (read-string "Bookmark display string: "
1867 (elpher-add-address-bookmark address bookmark-display-string)
1868 (elpher-reload-bookmarks)
1869 (message "Bookmark added."))
1870 (error "Cannot bookmark %s" display-string)))
1871 (error "No link selected"))))
1873 (defun elpher-unbookmark-current ()
1874 "Remove bookmark for the current page."
1876 (let ((address (elpher-page-address elpher-current-page)))
1877 (when (and (not (elpher-address-special-p address))
1878 (y-or-n-p "Really remove bookmark for the current page? "))
1879 (elpher-remove-address-bookmark address)
1880 (message "Bookmark removed."))))
1882 (defun elpher-unbookmark-link ()
1883 "Remove bookmark for the link at point."
1885 (let ((button (button-at (point))))
1887 (when (y-or-n-p "Really remove bookmark for this link? ")
1888 (let ((page (button-get button 'elpher-page)))
1889 (elpher-remove-address-bookmark (elpher-page-address page))
1890 (elpher-reload-bookmarks)
1891 (message "Bookmark removed.")))
1892 (error "No link selected"))))
1895 (defun elpher-bookmarks ()
1896 "Visit bookmarks page."
1898 (switch-to-buffer elpher-buffer-name)
1900 (elpher-make-page "Bookmarks Page" (elpher-make-special-address 'bookmarks))))
1902 (defun elpher-info-page (page)
1903 "Display information on PAGE."
1904 (let ((display-string (elpher-page-display-string page))
1905 (address (elpher-page-address page)))
1906 (if (elpher-address-special-p address)
1907 (message "Special page: %s" display-string)
1908 (message "%s" (elpher-address-to-url address)))))
1910 (defun elpher-info-link ()
1911 "Display information on page corresponding to link at point."
1913 (let ((button (button-at (point))))
1915 (elpher-info-page (button-get button 'elpher-page))
1916 (error "No item selected"))))
1918 (defun elpher-info-current ()
1919 "Display information on current page."
1921 (elpher-info-page elpher-current-page))
1923 (defun elpher-copy-page-url (page)
1924 "Copy URL representation of address of PAGE to `kill-ring'."
1925 (let ((address (elpher-page-address page)))
1926 (if (elpher-address-special-p address)
1927 (error (format "Cannot represent %s as URL" (elpher-page-display-string page)))
1928 (let ((url (elpher-address-to-url address)))
1929 (message "Copied \"%s\" to kill-ring/clipboard." url)
1932 (defun elpher-copy-link-url ()
1933 "Copy URL of item at point to `kill-ring'."
1935 (let ((button (button-at (point))))
1937 (elpher-copy-page-url (button-get button 'elpher-page))
1938 (error "No item selected"))))
1940 (defun elpher-copy-current-url ()
1941 "Copy URL of current page to `kill-ring'."
1943 (elpher-copy-page-url elpher-current-page))
1945 (defun elpher-set-gopher-coding-system ()
1946 "Specify an explicit character coding system for gopher selectors."
1948 (let ((system (read-coding-system "Set coding system to use for gopher (default is to autodetect): " nil)))
1949 (setq elpher-user-coding-system system)
1951 (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
1952 (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
1958 (defvar elpher-mode-map
1959 (let ((map (make-sparse-keymap)))
1960 (define-key map (kbd "TAB") 'elpher-next-link)
1961 (define-key map (kbd "<backtab>") 'elpher-prev-link)
1962 (define-key map (kbd "C-M-i") 'elpher-prev-link)
1963 (define-key map (kbd "u") 'elpher-back)
1964 (define-key map (kbd "U") 'elpher-back-to-start)
1965 (define-key map [mouse-3] 'elpher-back)
1966 (define-key map (kbd "O") 'elpher-root-dir)
1967 (define-key map (kbd "g") 'elpher-go)
1968 (define-key map (kbd "o") 'elpher-go-current)
1969 (define-key map (kbd "r") 'elpher-redraw)
1970 (define-key map (kbd "R") 'elpher-reload)
1971 (define-key map (kbd "T") 'elpher-toggle-tls)
1972 (define-key map (kbd ".") 'elpher-view-raw)
1973 (define-key map (kbd "d") 'elpher-download)
1974 (define-key map (kbd "D") 'elpher-download-current)
1975 (define-key map (kbd "m") 'elpher-jump)
1976 (define-key map (kbd "i") 'elpher-info-link)
1977 (define-key map (kbd "I") 'elpher-info-current)
1978 (define-key map (kbd "c") 'elpher-copy-link-url)
1979 (define-key map (kbd "C") 'elpher-copy-current-url)
1980 (define-key map (kbd "a") 'elpher-bookmark-link)
1981 (define-key map (kbd "A") 'elpher-bookmark-current)
1982 (define-key map (kbd "x") 'elpher-unbookmark-link)
1983 (define-key map (kbd "X") 'elpher-unbookmark-current)
1984 (define-key map (kbd "B") 'elpher-bookmarks)
1985 (define-key map (kbd "S") 'elpher-set-gopher-coding-system)
1986 (define-key map (kbd "F") 'elpher-forget-current-certificate)
1987 (when (fboundp 'evil-define-key*)
1988 (evil-define-key* 'motion map
1989 (kbd "TAB") 'elpher-next-link
1990 (kbd "C-") 'elpher-follow-current-link
1991 (kbd "C-t") 'elpher-back
1992 (kbd "u") 'elpher-back
1993 (kbd "U") 'elpher-back-to-start
1994 [mouse-3] 'elpher-back
1995 (kbd "g") 'elpher-go
1996 (kbd "o") 'elpher-go-current
1997 (kbd "r") 'elpher-redraw
1998 (kbd "R") 'elpher-reload
1999 (kbd "T") 'elpher-toggle-tls
2000 (kbd ".") 'elpher-view-raw
2001 (kbd "d") 'elpher-download
2002 (kbd "D") 'elpher-download-current
2003 (kbd "m") 'elpher-jump
2004 (kbd "i") 'elpher-info-link
2005 (kbd "I") 'elpher-info-current
2006 (kbd "c") 'elpher-copy-link-url
2007 (kbd "C") 'elpher-copy-current-url
2008 (kbd "a") 'elpher-bookmark-link
2009 (kbd "A") 'elpher-bookmark-current
2010 (kbd "x") 'elpher-unbookmark-link
2011 (kbd "X") 'elpher-unbookmark-current
2012 (kbd "B") 'elpher-bookmarks
2013 (kbd "S") 'elpher-set-gopher-coding-system
2014 (kbd "F") 'elpher-forget-current-certificate))
2016 "Keymap for gopher client.")
2018 (define-derived-mode elpher-mode special-mode "elpher"
2019 "Major mode for elpher, an elisp gopher client.
2021 This mode is automatically enabled by the interactive
2022 functions which initialize the gopher client, namely
2023 `elpher', `elpher-go' and `elpher-bookmarks'."
2024 (setq-local elpher-current-page nil)
2025 (setq-local elpher-history nil)
2026 (setq-local elpher-buffer-name (buffer-name)))
2028 (when (fboundp 'evil-set-initial-state)
2029 (evil-set-initial-state 'elpher-mode 'motion))
2032 ;;; Main start procedure
2036 (defun elpher (&optional arg)
2037 "Start elpher with default landing page.
2038 The buffer used for Elpher sessions is determined by the value of
2039 ‘elpher-buffer-name’. If there is already an Elpher session active in
2040 that buffer, Emacs will simply switch to it. Otherwise, a new session
2041 will begin. A numeric prefix arg (as in ‘C-u 42 M-x elpher RET’)
2042 switches to the session with that number, creating it if necessary. A
2043 nonnumeric prefix arg means to create a new session. Returns the
2044 buffer selected (or created)."
2046 (let* ((name (default-value 'elpher-buffer-name))
2047 (buf (cond ((numberp arg)
2048 (get-buffer-create (format "%s<%d>" name arg)))
2050 (generate-new-buffer name))
2052 (get-buffer-create name)))))
2053 (pop-to-buffer-same-window buf)
2054 (unless (buffer-modified-p)
2056 (let ((start-page (elpher-make-page "Elpher Start Page"
2057 (elpher-make-special-address 'start))))
2058 (elpher-visit-page start-page))
2059 "Started Elpher."))); Otherwise (elpher) evaluates to start page string.
2061 ;;; elpher.el ends here