1 ;;; elopher.el --- elisp gopher client
5 ;; An elisp gopher client.
12 (defconst elopher-version "1.0.0"
13 "Current version of elopher.")
15 (defconst elopher-margin-width 6
16 "Width of left-hand margin used when rendering indicies.")
18 (defconst elopher-start-index
21 (list "i\tfake\tfake\t1"
22 "i--------------------------------------------\tfake\tfake\t1"
23 "i Elopher Gopher Client \tfake\tfake\t1"
24 (format "i version %s\tfake\tfake\t1" elopher-version)
25 "i--------------------------------------------\tfake\tfake\t1"
27 "iBasic usage:\tfake\tfake\t1"
29 "i - tab/shift-tab: next/prev directory entry on current page\tfake\tfake\t1"
30 "i - RET/mouse-1: open directory entry under cursor\tfake\tfake\t1"
31 "i - u: return to parent directory entry\tfake\tfake\t1"
32 "i - g: go to a particular page\tfake\tfake\t1"
33 "i - r: redraw current page (using cached contents if available)\tfake\tfake\t1"
34 "i - R: reload current page (regenerates cache)\tfake\tfake\t1"
35 "i - d: download directory entry under cursor\tfake\tfake\t1"
36 "i - w: display the raw server response for the current page\tfake\tfake\t1"
38 "iPlaces to start exploring Gopherspace:\tfake\tfake\t1"
40 "1Floodgap Systems Gopher Server\t\tgopher.floodgap.com\t70"
42 "iAlternatively, select the following item and enter some\tfake\tfake\t1"
43 "isearch terms:\tfake\tfake\t1"
45 "7Veronica-2 Gopher Search Engine\t/v2/vs\tgopher.floodgap.com\t70"
48 "Source for elopher start page.")
51 ;;; Customization group
58 (defface elopher-index
59 '((((background dark)) :foreground "deep sky blue")
60 (((background light)) :foreground "blue"))
61 "Face used for index records.")
64 '((((background dark)) :foreground "white")
65 (((background light)) :weight bold))
66 "Face used for text records.")
68 (defface elopher-info '()
69 "Face used for info records.")
71 (defface elopher-image
72 '((((background dark)) :foreground "green")
73 (t :foreground "dark green"))
74 "Face used for image records.")
76 (defface elopher-search
77 '((((background light)) :foreground "orange")
78 (((background dark)) :foreground "dark orange"))
79 "Face used for search records.")
82 '((((background dark)) :foreground "yellow")
83 (((background light)) :foreground "dark red"))
84 "Face used for url records.")
86 (defface elopher-binary
87 '((t :foreground "magenta"))
88 "Face used for binary records.")
90 (defface elopher-unknown
91 '((t :foreground "red"))
92 "Face used for unknown record types.")
94 (defface elopher-margin-key
95 '((((background dark)) :foreground "white"))
96 "Face used for margin key.")
98 (defface elopher-margin-brackets
99 '((t :foreground "blue"))
100 "Face used for brackets around margin key.")
102 (defcustom elopher-open-urls-with-eww nil
103 "If non-nil, open URL selectors using eww.
104 Otherwise, use the system browser via the BROWSE-URL function."
112 (defun elopher-make-address (selector host port)
113 "Create an address of a gopher object with SELECTOR, HOST and PORT."
114 (list selector host port))
116 (defun elopher-address-selector (address)
117 "Retrieve selector from ADDRESS."
120 (defun elopher-address-host (address)
121 "Retrieve host from ADDRESS."
124 (defun elopher-address-port (address)
125 "Retrieve port from ADDRESS."
130 (defun elopher-make-node (parent address getter &optional content pos)
131 "Create a node in the gopher page hierarchy.
133 PARENT specifies the parent of the node, ADDRESS specifies the address of
134 the gopher page, GETTER provides the getter function used to obtain this
137 The optional arguments CONTENT and POS can be used to fill the cached
138 content and cursor position fields of the node."
139 (list parent address getter content pos))
141 (defun elopher-node-parent (node)
142 "Retrieve the parent node of NODE."
145 (defun elopher-node-address (node)
146 "Retrieve the address of NODE."
149 (defun elopher-node-getter (node)
150 "Retrieve the preferred getter function of NODE."
153 (defun elopher-node-content (node)
154 "Retrieve the cached content of NODE, or nil if none exists."
157 (defun elopher-node-pos (node)
158 "Retrieve the cached cursor position for NODE, or nil if none exists."
161 (defun elopher-set-node-content (node content)
162 "Set the content cache of NODE to CONTENT."
163 (setcar (nthcdr 3 node) content))
165 (defun elopher-set-node-pos (node pos)
166 "Set the cursor position cache of NODE to POS."
167 (setcar (nthcdr 4 node) pos))
169 ;; Node graph traversal
171 (defvar elopher-current-node)
173 (defun elopher-visit-node (node &optional getter)
174 "Visit NODE using its own getter or GETTER, if non-nil."
176 (elopher-process-cleanup)
177 (setq elopher-current-node node)
180 (funcall (elopher-node-getter node))))
182 (defun elopher-visit-parent-node ()
183 "Visit the parent of the current node."
184 (let ((parent-node (elopher-node-parent elopher-current-node)))
186 (elopher-visit-node parent-node))))
188 (defun elopher-reload-current-node ()
189 "Reload the current node, discarding any existing cached content."
190 (elopher-set-node-content elopher-current-node nil)
191 (elopher-visit-node elopher-current-node))
193 (defun elopher-save-pos ()
194 "Save the current position of point to the current node."
195 (when elopher-current-node
196 (elopher-set-node-pos elopher-current-node (point))))
198 (defun elopher-restore-pos ()
199 "Restore the position of point to that cached in the current node."
200 (let ((pos (elopher-node-pos elopher-current-node)))
203 (goto-char (point-min)))))
205 ;;; Buffer preparation
208 (defmacro elopher-with-clean-buffer (&rest args)
209 "Evaluate ARGS with a clean *elopher* buffer as current."
211 '(switch-to-buffer "*elopher*")
213 (append (list 'let '((inhibit-read-only t))
220 (defun elopher-insert-index (string)
221 "Insert the index corresponding to STRING into the current buffer."
222 (dolist (line (split-string string "\r\n"))
223 (unless (= (length line) 0)
224 (elopher-insert-index-record line))))
226 (defun elopher-insert-margin (&optional type-name)
227 "Insert index margin, optionally containing the TYPE-NAME, into the current buffer."
230 (insert (format (concat "%" (number-to-string (- elopher-margin-width 1)) "s")
232 (propertize "[" 'face 'elopher-margin-brackets)
233 (propertize type-name 'face 'elopher-margin-key)
234 (propertize "]" 'face 'elopher-margin-brackets))))
236 (insert (make-string elopher-margin-width ?\s))))
238 (defvar elopher-type-map
239 '((?0 elopher-get-text-node "T" elopher-text)
240 (?1 elopher-get-index-node "/" elopher-index)
241 (?g elopher-get-image-node "im" elopher-image)
242 (?p elopher-get-image-node "im" elopher-image)
243 (?I elopher-get-image-node "im" elopher-image)
244 (?4 elopher-get-node-download "B" elopher-binary)
245 (?5 elopher-get-node-download "B" elopher-binary)
246 (?9 elopher-get-node-download "B" elopher-binary)
247 (?7 elopher-get-search-node "?" elopher-search))
248 "Association list from types to getters, margin codes and index faces.")
250 (defun elopher-insert-index-record (line)
251 "Insert the index record corresponding to LINE into the current buffer."
252 (let* ((type (elt line 0))
253 (fields (split-string (substring line 1) "\t"))
254 (display-string (elt fields 0))
255 (selector (elt fields 1))
256 (host (elt fields 2))
257 (port (elt fields 3))
258 (address (elopher-make-address selector host port))
259 (type-map-entry (alist-get type elopher-type-map)))
261 (let ((getter (car type-map-entry))
262 (margin-code (cadr type-map-entry))
263 (face (caddr type-map-entry)))
264 (elopher-insert-margin margin-code)
265 (insert-text-button display-string
267 'elopher-node (elopher-make-node elopher-current-node
270 'action #'elopher-click-link
272 'help-echo (format "mouse-1, RET: open %s on %s port %s"
273 selector host port)))
275 (?i (elopher-insert-margin) ; Information
276 (insert (propertize display-string
277 'face 'elopher-info)))
278 (?h (elopher-insert-margin "W") ; Web link
279 (let ((url (elt (split-string selector "URL:") 1)))
280 (insert-text-button display-string
283 'action #'elopher-click-url
285 'help-echo (format "mouse-1, RET: open url %s" url))))
286 (?.) ; Occurs at end of index, can safely ignore.
287 (tp (elopher-insert-margin (concat (char-to-string tp) "?"))
288 (insert (propertize display-string
289 'face 'elopher-unknown-face)))))
293 ;;; Selector retrieval (all kinds)
296 (defun elopher-process-cleanup ()
297 "Immediately shut down any extant elopher process."
298 (let ((p (get-process "elopher-process")))
299 (if p (delete-process p))))
301 (defvar elopher-selector-string)
303 (defun elopher-get-selector (address after)
304 "Retrieve selector specified by ADDRESS, then execute AFTER.
305 The result is stored as a string in the variable elopher-selector-string."
306 (setq elopher-selector-string "")
307 (make-network-process
308 :name "elopher-process"
309 :host (elopher-address-host address)
310 :service (elopher-address-port address)
311 :filter (lambda (proc string)
312 (setq elopher-selector-string (concat elopher-selector-string string)))
314 (process-send-string "elopher-process"
315 (concat (elopher-address-selector address) "\n")))
319 (defun elopher-get-index-node ()
320 "Getter which retrieves the current node contents as an index."
321 (let ((content (elopher-node-content elopher-current-node))
322 (address (elopher-node-address elopher-current-node)))
325 (elopher-with-clean-buffer
327 (elopher-restore-pos))
330 (elopher-with-clean-buffer
331 (insert "LOADING DIRECTORY..."))
332 (elopher-get-selector address
334 (unless (string-prefix-p "deleted" event)
335 (elopher-with-clean-buffer
336 (elopher-insert-index elopher-selector-string))
337 (elopher-restore-pos)
338 (elopher-set-node-content elopher-current-node
341 (elopher-with-clean-buffer
342 (elopher-insert-index elopher-start-index))
343 (elopher-restore-pos)
344 (elopher-set-node-content elopher-current-node
345 (buffer-string)))))))
349 (defconst elopher-url-regex
350 "\\(https?\\|gopher\\)://\\([a-zA-Z0-9.\-]+\\)\\(?3::[0-9]+\\)?\\(?4:/[^ \r\n\t(),]*\\)?"
351 "Regexp used to locate and buttinofy URLs in text files loaded by elopher.")
353 (defun elopher-buttonify-urls (string)
354 "Turn substrings which look like urls in STRING into clickable buttons."
357 (goto-char (point-min))
358 (while (re-search-forward elopher-url-regex nil t)
359 (let ((url (match-string 0))
360 (protocol (downcase (match-string 1))))
361 (if (string= protocol "gopher")
362 (let* ((host (match-string 2))
364 (type-and-selector (match-string 4))
365 (type (if (> (length type-and-selector) 1)
366 (elt type-and-selector 1)
368 (selector (if (> (length type-and-selector) 1)
369 (substring type-and-selector 2)
371 (address (elopher-make-address selector host port))
372 (getter (car (alist-get type elopher-type-map))))
373 (make-text-button (match-beginning 0)
375 'elopher-node (elopher-make-node elopher-current-node
378 'action #'elopher-click-link
380 'help-echo (format "mouse-1, RET: open %s on %s port %s"
381 selector host port)))
382 (make-text-button (match-beginning 0)
385 'action #'elopher-click-url
387 'help-echo (format "mouse-1, RET: open url %s" url)))))
390 (defun elopher-process-text (string)
391 "Remove CRs and trailing period from the gopher text document STRING."
392 (let* ((chopped-str (replace-regexp-in-string "\r\n\.\r\n$" "\r\n" string))
393 (cleaned-str (replace-regexp-in-string "\r" "" chopped-str)))
394 (elopher-buttonify-urls cleaned-str)))
396 (defun elopher-get-text-node ()
397 "Getter which retrieves the current node contents as a text document."
398 (let ((content (elopher-node-content elopher-current-node))
399 (address (elopher-node-address elopher-current-node)))
402 (elopher-with-clean-buffer
404 (elopher-restore-pos))
406 (elopher-with-clean-buffer
407 (insert "LOADING TEXT..."))
408 (elopher-get-selector address
410 (unless (string-prefix-p "deleted" event)
411 (elopher-with-clean-buffer
412 (insert (elopher-process-text elopher-selector-string)))
413 (elopher-restore-pos)
414 (elopher-set-node-content elopher-current-node
415 (buffer-string)))))))))
419 (defun elopher-get-image-node ()
420 "Getter which retrieves the current node contents as an image to view."
421 (let ((content (elopher-node-content elopher-current-node))
422 (address (elopher-node-address elopher-current-node)))
425 (elopher-with-clean-buffer
426 (insert-image content))
427 (setq cursor-type nil)
428 (elopher-restore-pos))
430 (elopher-with-clean-buffer
431 (insert "LOADING IMAGE..."))
432 (elopher-get-selector address
434 (unless (string-prefix-p "deleted" event)
435 (let ((image (create-image
436 (encode-coding-string elopher-selector-string
439 (elopher-with-clean-buffer
440 (insert-image image))
441 (setq cursor-type nil)
442 (elopher-restore-pos)
443 (elopher-set-node-content elopher-current-node
448 (defun elopher-get-search-node ()
449 "Getter which submits a search query to the address of the current node."
450 (let ((content (elopher-node-content elopher-current-node))
451 (address (elopher-node-address elopher-current-node))
455 (elopher-with-clean-buffer
457 (elopher-restore-pos)
458 (message "Displaying cached search results. Reload to perform a new search."))
460 (let* ((query-string (read-string "Query: "))
461 (query-selector (concat (elopher-address-selector address) "\t" query-string))
462 (search-address (elopher-make-address query-selector
463 (elopher-address-host address)
464 (elopher-address-port address))))
466 (elopher-with-clean-buffer
467 (insert "LOADING RESULTS..."))
468 (elopher-get-selector search-address
470 (unless (string-prefix-p "deleted" event)
471 (elopher-with-clean-buffer
472 (elopher-insert-index elopher-selector-string))
473 (goto-char (point-min))
474 (elopher-set-node-content elopher-current-node
477 (elopher-visit-parent-node))))))
479 ;; Raw server response retrieval
481 (defun elopher-get-node-raw ()
482 "Getter which retrieves the raw server response for the current node."
483 (let* ((content (elopher-node-content elopher-current-node))
484 (address (elopher-node-address elopher-current-node)))
485 (elopher-with-clean-buffer
486 (insert "LOADING RAW SERVER RESPONSE..."))
488 (elopher-get-selector address
490 (unless (string-prefix-p "deleted" event)
491 (elopher-with-clean-buffer
492 (insert elopher-selector-string))
493 (goto-char (point-min)))))
495 (elopher-with-clean-buffer
496 (insert elopher-start-index))
497 (goto-char (point-min)))))
498 (message "Displaying raw server response. Reload or redraw to return to standard view."))
500 ;; File export retrieval
502 (defvar elopher-download-filename)
504 (defun elopher-get-node-download ()
505 "Getter which retrieves the current node and writes the result to a file."
506 (let* ((address (elopher-node-address elopher-current-node))
507 (selector (elopher-address-selector address)))
508 (elopher-visit-parent-node) ; Do first in case of non-local exits.
509 (let* ((filename-proposal (file-name-nondirectory selector))
510 (filename (read-file-name "Save file as: "
512 (if (> (length filename-proposal) 0)
515 (message "Downloading...")
516 (setq elopher-download-filename filename)
517 (elopher-get-selector address
519 (let ((coding-system-for-write 'binary))
520 (with-temp-file elopher-download-filename
521 (insert elopher-selector-string)
522 (message (format "Download complate, saved to file %s."
523 elopher-download-filename)))))))))
526 ;;; Navigation procedures
529 (defun elopher-next-link ()
530 "Move point to the next link on the current page."
534 (defun elopher-prev-link ()
535 "Move point to the previous link on the current page."
539 (defun elopher-click-link (button)
540 "Function called when the gopher link BUTTON is activated (via mouse or keypress)."
541 (let ((node (button-get button 'elopher-node)))
542 (elopher-visit-node node)))
544 (defun elopher-click-url (button)
545 "Function called when the url link BUTTON is activated (via mouse or keypress)."
546 (let ((url (button-get button 'elopher-url)))
547 (if elopher-open-urls-with-eww
551 (defun elopher-follow-current-link ()
552 "Open the link or url at point."
557 "Go to a particular gopher site."
560 (hostname (read-string "Gopher host: "))
561 (selector (read-string "Selector (default none): " nil nil ""))
562 (port (read-string "Port (default 70): " nil nil 70))
563 (address (list selector hostname port)))
565 (elopher-make-node elopher-current-node
567 #'elopher-get-index-node))))
569 (defun elopher-redraw ()
570 "Redraw current page."
572 (elopher-visit-node elopher-current-node))
574 (defun elopher-reload ()
575 "Reload current page."
577 (elopher-reload-current-node))
579 (defun elopher-view-raw ()
580 "View current page as plain text."
582 (elopher-visit-node elopher-current-node
583 #'elopher-get-node-raw))
585 (defun elopher-back ()
586 "Go to previous site."
588 (if (elopher-node-parent elopher-current-node)
589 (elopher-visit-parent-node)
590 (message "No previous site.")))
592 (defun elopher-download ()
593 "Download the link at point."
595 (let ((button (button-at (point))))
597 (let ((node (button-get button 'elopher-node)))
599 (elopher-visit-node (button-get button 'elopher-node)
600 #'elopher-get-node-download)
601 (message "Can only download gopher links, not general URLs.")))
602 (message "No link selected."))))
607 (defvar elopher-mode-map
608 (let ((map (make-sparse-keymap)))
609 (define-key map (kbd "TAB") 'elopher-next-link)
610 (define-key map (kbd "<backtab>") 'elopher-prev-link)
611 (define-key map (kbd "u") 'elopher-back)
612 (define-key map (kbd "g") 'elopher-go)
613 (define-key map (kbd "r") 'elopher-redraw)
614 (define-key map (kbd "R") 'elopher-reload)
615 (define-key map (kbd "w") 'elopher-view-raw)
616 (define-key map (kbd "d") 'elopher-download)
617 (when (fboundp 'evil-define-key)
618 (evil-define-key 'normal map
619 (kbd "TAB") 'elopher-next-link
620 (kbd "C-]") 'elopher-follow-current-link
621 (kbd "C-t") 'elopher-back
622 (kbd "u") 'elopher-back
623 (kbd "g") 'elopher-go
624 (kbd "r") 'elopher-redraw
625 (kbd "R") 'elopher-reload
626 (kbd "w") 'elopher-view-raw
627 (kbd "d") 'elopher-download))
629 "Keymap for gopher client.")
631 (define-derived-mode elopher-mode special-mode "elopher"
632 "Major mode for elopher, an elisp gopher client.")
635 ;;; Main start procedure
640 "Start elopher with default landing page."
642 (setq elopher-current-node nil)
643 (let ((start-node (elopher-make-node nil nil #'elopher-get-index-node)))
644 (elopher-visit-node start-node))
645 "Started Elopher.") ; Otherwise (elopher) evaluates to start page string.
647 ;;; elopher.el ends here