;;; elpher.el --- A friendly gopher client. ;; Copyright (C) 2019 Tim Vaughan ;; Author: Tim Vaughan ;; Created: 11 April 2019 ;; Version: 1.4.3 ;; Keywords: comm gopher ;; Homepage: https://github.com/tgvaughan/elpher ;; Package-Requires: ((emacs "25")) ;; This file is not part of GNU Emacs. ;; This program is free software: you can redistribute it and/or modify ;; it under the terms of the GNU General Public License as published by ;; the Free Software Foundation, either version 3 of the License, or ;; (at your option) any later version. ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; You should have received a copy of the GNU General Public License ;; along with this file. If not, see . ;;; Commentary: ;; Elpher aims to provide a practical and friendly gopher client ;; for GNU Emacs. It supports: ;; - an intuitive keyboard and mouse-driven interface, ;; - caching of visited sites (both content and cursor position), ;; - pleasant and configurable colouring of Gopher directories, ;; - direct visualisation of image files, ;; - (m)enu key support, similar to Emacs' info browser, ;; - clickable web and gopher links in plain text, ;; - a simple bookmark management system, ;; - support for TLS gopherholes. ;; To launch Elpher, simply use 'M-x elpher'. This will open a start ;; page containing information on key bindings and suggested starting ;; points for your gopher exploration. ;; Faces, caching and other options can be configured via ;; the Elpher customization group in Applications. ;; Elpher is under active development, and any suggestions for ;; improvements are welcome! ;;; Code: (provide 'elpher) (require 'seq) (require 'pp) (require 'shr) ;;; Global constants ;; (defconst elpher-version "1.4.3" "Current version of elpher.") (defconst elpher-margin-width 6 "Width of left-hand margin used when rendering indicies.") (defconst elpher-start-index (mapconcat 'identity (list "i\tfake\tfake\t1" "i --------------------------------------------\tfake\tfake\t1" "i Elpher Gopher Client \tfake\tfake\t1" (format "i version %s\tfake\tfake\t1" elpher-version) "i --------------------------------------------\tfake\tfake\t1" "i\tfake\tfake\t1" "iUsage:\tfake\tfake\t1" "i\tfake\tfake\t1" "i - tab/shift-tab: next/prev item on current page\tfake\tfake\t1" "i - RET/mouse-1: open item under cursor\tfake\tfake\t1" "i - m: select an item on current page by name (autocompletes)\tfake\tfake\t1" "i - u: return to parent\tfake\tfake\t1" "i - O: visit the root menu of the current server\tfake\tfake\t1" "i - g: go to a particular gopher address\tfake\tfake\t1" "i - i/I: info on item under cursor or current page\tfake\tfake\t1" "i - c/C: copy URL representation of item under cursor or current page\tfake\tfake\t1" "i - a/A: bookmark the item under cursor or current page\tfake\tfake\t1" "i - x/X: remove bookmark for item under cursor or current page\tfake\tfake\t1" "i - B: visit the bookmarks page\tfake\tfake\t1" "i - r: redraw current page (using cached contents if available)\tfake\tfake\t1" "i - R: reload current page (regenerates cache)\tfake\tfake\t1" "i - T: toggle TLS mode\tfake\tfake\t1" "i - d/D: download item under cursor or current page\tfake\tfake\t1" "i - w: display the raw server response for the current page\tfake\tfake\t1" "i - S: set an explicit character coding system (default is to autodetect)\tfake\tfake\t1" "i\tfake\tfake\t1" "iWhere to start exploring Gopherspace:\tfake\tfake\t1" "i\tfake\tfake\t1" "1Floodgap Systems Gopher Server\t/\tgopher.floodgap.com\t70" "i\tfake\tfake\t1" "iAlternatively, select the following item and enter some\tfake\tfake\t1" "isearch terms:\tfake\tfake\t1" "i\tfake\tfake\t1" "7Veronica-2 Gopher Search Engine\t/v2/vs\tgopher.floodgap.com\t70" ".\r\n") "\r\n") "Source for elpher start page.") (defconst elpher-type-map '((?0 elpher-get-text-node "txt" elpher-text) (?1 elpher-get-index-node "/" elpher-index) (?4 elpher-get-node-download "bin" elpher-binary) (?5 elpher-get-node-download "bin" elpher-binary) (?7 elpher-get-search-node "?" elpher-search) (?8 elpher-get-telnet-node "tel" elpher-telnet) (?9 elpher-get-node-download "bin" elpher-binary) (?g elpher-get-image-node "img" elpher-image) (?p elpher-get-image-node "img" elpher-image) (?I elpher-get-image-node "img" elpher-image) (?d elpher-get-node-download "doc" elpher-binary) (?h elpher-get-url-node "web" elpher-url) (bookmarks elpher-get-bookmarks-node "#" elpher-index) (start elpher-get-start-node "#" elpher-index)) "Association list from types to getters, margin codes and index faces.") ;;; Customization group ;; (defgroup elpher nil "A gopher client." :group 'applications) ;; Face customizations (defface elpher-index '((t :inherit font-lock-keyword-face)) "Face used for directory type directory records.") (defface elpher-text '((t :inherit bold)) "Face used for text type directory records.") (defface elpher-info '((t :inherit default)) "Face used for info type directory records.") (defface elpher-image '((t :inherit font-lock-string-face)) "Face used for image type directory records.") (defface elpher-search '((t :inherit warning)) "Face used for search type directory records.") (defface elpher-url '((t :inherit font-lock-comment-face)) "Face used for url type directory records.") (defface elpher-telnet '((t :inherit font-lock-function-name-face)) "Face used for telnet type directory records.") (defface elpher-binary '((t :inherit font-lock-doc-face)) "Face used for binary type directory records.") (defface elpher-unknown '((t :inherit error)) "Face used for directory records with unknown/unsupported types.") (defface elpher-margin-key '((t :inherit bold)) "Face used for directory margin key.") (defface elpher-margin-brackets '((t :inherit shadow)) "Face used for brackets around directory margin key.") ;; Other customizations (defcustom elpher-open-urls-with-eww nil "If non-nil, open URL selectors using eww. Otherwise, use the system browser via the BROWSE-URL function." :type '(boolean)) (defcustom elpher-buttonify-urls-in-directories nil "If non-nil, turns URLs matched in directories into clickable buttons." :type '(boolean)) (defcustom elpher-cache-images nil "If non-nil, cache images in memory in the same way as other content." :type '(boolean)) (defcustom elpher-use-header t "If non-nil, display current node information in buffer header." :type '(boolean)) (defcustom elpher-auto-disengage-TLS nil "If non-nil, automatically disengage TLS following an unsuccessful connection. While enabling this may seem convenient, it is also potentially dangerous as it allows switching from an encrypted channel back to plain text without user input." :type '(boolean)) ;;; Model ;; ;; Address (defun elpher-make-address (type &optional selector host port use-tls) "Create an address of a gopher object with TYPE, SELECTOR, HOST and PORT. Although selector host and port are optional, they are only omitted for special address types, such as 'start for the start page. Setting the USE-TLS parameter to non-nil causes Elpher to engage TLS mode before attempting to connect to the server." (if use-tls (list type selector host port 'tls) (list type selector host port))) (defun elpher-address-type (address) "Retrieve type from ADDRESS." (elt address 0)) (defun elpher-address-selector (address) "Retrieve selector from ADDRESS." (elt address 1)) (defun elpher-address-host (address) "Retrieve host from ADDRESS." (elt address 2)) (defun elpher-address-port (address) "Retrieve port from ADDRESS." (elt address 3)) (defun elpher-address-use-tls-p (address) "Return non-nil if ADDRESS is marked as needing TLS." (elt address 4)) (defun elpher-address-special-p (address) "Return non-nil if ADDRESS is special (e.g. start page, bookmarks page)." (not (elpher-address-host address))) ;; Node (defun elpher-make-node (display-string address &optional parent) "Create a node in the gopher page hierarchy. DISPLAY-STRING records the display string used for the page. ADDRESS specifies the address of the gopher page. The optional PARENT specifies the parent node in the hierarchy. This is set every time the node is visited, so while it forms an important part of the node data there is no need to set it initially." (list display-string address parent)) (defun elpher-node-display-string (node) "Retrieve the display string of NODE." (elt node 0)) (defun elpher-node-address (node) "Retrieve the address of NODE." (elt node 1)) (defun elpher-node-parent (node) "Retrieve the parent node of NODE." (elt node 2)) (defun elpher-set-node-parent (node parent) "Set the parent node of NODE to be PARENT." (setcar (cdr (cdr node)) parent)) ;; Cache (defvar elpher-content-cache (make-hash-table :test 'equal)) (defvar elpher-pos-cache (make-hash-table :test 'equal)) (defun elpher-get-cached-content (address) "Retrieve the cached content for ADDRESS, or nil if none exists." (gethash address elpher-content-cache)) (defun elpher-cache-content (address content) "Set the content cache for ADDRESS to CONTENT." (puthash address content elpher-content-cache)) (defun elpher-get-cached-pos (address) "Retrieve the cached cursor position for ADDRESS, or nil if none exists." (gethash address elpher-pos-cache)) (defun elpher-cache-pos (address pos) "Set the cursor position cache for ADDRESS to POS." (puthash address pos elpher-pos-cache)) ;; Node graph traversal (defvar elpher-current-node nil) (defun elpher-visit-node (node &optional getter preserve-parent) "Visit NODE using its own getter or GETTER, if non-nil. Additionally, set the parent of NODE to `elpher-current-node', unless PRESERVE-PARENT is non-nil." (elpher-save-pos) (elpher-process-cleanup) (unless preserve-parent (if (and (elpher-node-parent elpher-current-node) (equal (elpher-node-address elpher-current-node) (elpher-node-address node))) (elpher-set-node-parent node (elpher-node-parent elpher-current-node)) (elpher-set-node-parent node elpher-current-node))) (setq elpher-current-node node) (if getter (funcall getter) (let* ((address (elpher-node-address node)) (type (elpher-address-type address))) (funcall (car (alist-get type elpher-type-map)))))) (defun elpher-visit-parent-node () "Visit the parent of the current node." (let ((parent-node (elpher-node-parent elpher-current-node))) (when parent-node (elpher-visit-node parent-node nil t)))) (defun elpher-reload-current-node () "Reload the current node, discarding any existing cached content." (elpher-cache-content (elpher-node-address elpher-current-node) nil) (elpher-visit-node elpher-current-node)) (defun elpher-save-pos () "Save the current position of point to the current node." (when elpher-current-node (elpher-cache-pos (elpher-node-address elpher-current-node) (point)))) (defun elpher-restore-pos () "Restore the position of point to that cached in the current node." (let ((pos (elpher-get-cached-pos (elpher-node-address elpher-current-node)))) (if pos (goto-char pos) (goto-char (point-min))))) ;;; Buffer preparation ;; (defun elpher-update-header () "If `elpher-use-header' is true, display current node info in window header." (if elpher-use-header (setq header-line-format (elpher-node-display-string elpher-current-node)))) (defmacro elpher-with-clean-buffer (&rest args) "Evaluate ARGS with a clean *elpher* buffer as current." (list 'with-current-buffer "*elpher*" '(elpher-mode) (append (list 'let '((inhibit-read-only t)) '(erase-buffer) '(elpher-update-header)) args))) ;;; Text Processing ;; (defvar elpher-user-coding-system nil "User-specified coding system to use for decoding text responses.") (defun elpher-decode (string) "Decode STRING using autodetected or user-specified coding system." (decode-coding-string string (if elpher-user-coding-system elpher-user-coding-system (detect-coding-string string t)))) (defun elpher-preprocess-text-response (string) "Preprocess text selector response contained in STRING. This involes decoding the character representation, and clearing away CRs and any terminating period." (elpher-decode (replace-regexp-in-string "\n\.\n$" "\n" (replace-regexp-in-string "\r" "" string)))) ;;; Index rendering ;; (defun elpher-insert-index (string) "Insert the index corresponding to STRING into the current buffer." ;; Should be able to split directly on CRLF, but some non-conformant ;; LF-only servers sadly exist, hence the following. (let ((str-processed (elpher-preprocess-text-response string))) (dolist (line (split-string str-processed "\n")) (unless (= (length line) 0) (let* ((type (elt line 0)) (fields (split-string (substring line 1) "\t")) (display-string (elt fields 0)) (selector (elt fields 1)) (host (elt fields 2)) (port (if (elt fields 3) (string-to-number (elt fields 3)) nil)) (address (elpher-make-address type selector host port))) (elpher-insert-index-record display-string address)))))) (defun elpher-insert-margin (&optional type-name) "Insert index margin, optionally containing the TYPE-NAME, into the current buffer." (if type-name (progn (insert (format (concat "%" (number-to-string (- elpher-margin-width 1)) "s") (concat (propertize "[" 'face 'elpher-margin-brackets) (propertize type-name 'face 'elpher-margin-key) (propertize "]" 'face 'elpher-margin-brackets)))) (insert " ")) (insert (make-string elpher-margin-width ?\s)))) (defun elpher-node-button-help (node) "Return a string containing the help text for a button corresponding to NODE." (let ((address (elpher-node-address node))) (if (eq (elpher-address-type address) ?h) (let ((url (cadr (split-string (elpher-address-selector address) "URL:")))) (format "mouse-1, RET: open url '%s'" url)) (format "mouse-1, RET: open '%s' on %s port %s" (elpher-address-selector address) (elpher-address-host address) (elpher-address-port address))))) (defun elpher-insert-index-record (display-string address) "Function to insert an index record into the current buffer. The contents of the record are dictated by DISPLAY-STRING and ADDRESS." (let* ((type (elpher-address-type address)) (type-map-entry (alist-get type elpher-type-map))) (if type-map-entry (let* ((margin-code (elt type-map-entry 1)) (face (elt type-map-entry 2)) (node (elpher-make-node display-string address))) (elpher-insert-margin margin-code) (insert-text-button display-string 'face face 'elpher-node node 'action #'elpher-click-link 'follow-link t 'help-echo (elpher-node-button-help node))) (pcase type (?i ;; Information (elpher-insert-margin) (insert (propertize (if elpher-buttonify-urls-in-directories (elpher-buttonify-urls display-string) display-string) 'face 'elpher-info))) (other ;; Unknown (elpher-insert-margin (concat (char-to-string type) "?")) (insert (propertize display-string 'face 'elpher-unknown))))) (insert "\n"))) (defun elpher-click-link (button) "Function called when the gopher link BUTTON is activated (via mouse or keypress)." (let ((node (button-get button 'elpher-node))) (elpher-visit-node node))) ;;; Selector retrieval (all kinds) ;; (defun elpher-process-cleanup () "Immediately shut down any extant elpher process." (let ((p (get-process "elpher-process"))) (if p (delete-process p)))) (defvar elpher-use-tls nil "If non-nil, use TLS to communicate with gopher servers.") (defvar elpher-selector-string) (defun elpher-get-selector (address after &optional propagate-error) "Retrieve selector specified by ADDRESS, then execute AFTER. The result is stored as a string in the variable ‘elpher-selector-string’. Usually errors result in an error page being displayed. This is only appropriate if the selector is to be directly viewed. If PROPAGATE-ERROR is non-nil, this message is not displayed. Instead, the error propagates up to the calling function." (setq elpher-selector-string "") (when (elpher-address-use-tls-p address) (if (gnutls-available-p) (when (not elpher-use-tls) (setq elpher-use-tls t) (message "Engaging TLS mode.")) (error "Cannot retrieve TLS selector: GnuTLS not available"))) (condition-case the-error (let* ((kill-buffer-query-functions nil) (proc (open-network-stream "elpher-process" nil (elpher-address-host address) (elpher-address-port address) :type (if elpher-use-tls 'tls 'plain)))) (set-process-coding-system proc 'binary) (set-process-filter proc (lambda (proc string) (setq elpher-selector-string (concat elpher-selector-string string)))) (set-process-sentinel proc after) (process-send-string proc (concat (elpher-address-selector address) "\n"))) (error (if (and (consp the-error) (eq (car the-error) 'gnutls-error) (not (elpher-address-use-tls-p address)) (or elpher-auto-disengage-TLS (yes-or-no-p "Could not establish encrypted connection. Disable TLS mode? "))) (progn (message "Disengaging TLS mode.") (setq elpher-use-tls nil) (elpher-get-selector address after)) (elpher-process-cleanup) (if propagate-error (error the-error) (elpher-with-clean-buffer (insert (propertize "\n---- ERROR -----\n\n" 'face 'error) "Failed to connect to " (elpher-get-address-url address) ".\n" (propertize "\n----------------\n\n" 'face 'error) "Press 'u' to return to the previous page."))))))) ;; Index retrieval (defun elpher-get-index-node () "Getter which retrieves the current node contents as an index." (let* ((address (elpher-node-address elpher-current-node)) (content (elpher-get-cached-content address))) (if content (progn (elpher-with-clean-buffer (insert content) (elpher-restore-pos))) (elpher-with-clean-buffer (insert "LOADING DIRECTORY... (use 'u' to cancel)")) (elpher-get-selector address (lambda (proc event) (unless (string-prefix-p "deleted" event) (elpher-with-clean-buffer (elpher-insert-index elpher-selector-string) (elpher-restore-pos) (elpher-cache-content (elpher-node-address elpher-current-node) (buffer-string))))))))) ;; Text retrieval (defconst elpher-url-regex "\\([a-zA-Z]+\\)://\\([a-zA-Z0-9.\-]+\\)\\(?3::[0-9]+\\)?\\(?4:/[^ \r\n\t(),]*\\)?" "Regexp used to locate and buttinofy URLs in text files loaded by elpher.") (defun elpher-make-node-from-matched-url (&optional string) "Convert most recent `elpher-url-regex' match to a node. If STRING is non-nil, this is given as an argument to all `match-string' calls, as is necessary if the match is performed by `string-match'." (let ((url (match-string 0 string)) (protocol (downcase (match-string 1 string)))) (if (or (string= protocol "gopher") (string= protocol "gophers")) (let* ((host (match-string 2 string)) (port (if (> (length (match-string 3 string)) 1) (string-to-number (substring (match-string 3 string) 1)) 70)) (type-and-selector (match-string 4 string)) (type (if (> (length type-and-selector) 1) (elt type-and-selector 1) ?1)) (selector (if (> (length type-and-selector) 1) (substring type-and-selector 2) "")) (use-tls (string= protocol "gophers")) (address (elpher-make-address type selector host port use-tls))) (elpher-make-node url address)) (let* ((host (match-string 2 string)) (port (if (> (length (match-string 3 string)) 1) (string-to-number (substring (match-string 3 string) 1)) 70)) (selector (concat "URL:" url)) (address (elpher-make-address ?h selector host port))) (elpher-make-node url address))))) (defun elpher-buttonify-urls (string) "Turn substrings which look like urls in STRING into clickable buttons." (with-temp-buffer (insert string) (goto-char (point-min)) (while (re-search-forward elpher-url-regex nil t) (let ((node (elpher-make-node-from-matched-url))) (make-text-button (match-beginning 0) (match-end 0) 'elpher-node node 'action #'elpher-click-link 'follow-link t 'help-echo (elpher-node-button-help node)))) (buffer-string))) (defun elpher-get-text-node () "Getter which retrieves the current node contents as a text document." (let* ((address (elpher-node-address elpher-current-node)) (content (elpher-get-cached-content address))) (if content (progn (elpher-with-clean-buffer (insert content) (elpher-restore-pos))) (progn (elpher-with-clean-buffer (insert "LOADING TEXT... (use 'u' to cancel)")) (elpher-get-selector address (lambda (proc event) (unless (string-prefix-p "deleted" event) (elpher-with-clean-buffer (insert (elpher-buttonify-urls (elpher-preprocess-text-response elpher-selector-string))) (elpher-restore-pos) (elpher-cache-content (elpher-node-address elpher-current-node) (buffer-string)))))))))) ;; Image retrieval (defun elpher-get-image-node () "Getter which retrieves the current node contents as an image to view." (let* ((address (elpher-node-address elpher-current-node)) (content (elpher-get-cached-content address))) (if content (progn (elpher-with-clean-buffer (insert-image content) (elpher-restore-pos))) (if (display-images-p) (progn (elpher-with-clean-buffer (insert "LOADING IMAGE... (use 'u' to cancel)")) (elpher-get-selector address (lambda (proc event) (unless (string-prefix-p "deleted" event) (let ((image (create-image elpher-selector-string nil t))) (elpher-with-clean-buffer (insert-image image) (elpher-restore-pos)) (if elpher-cache-images (elpher-cache-content (elpher-node-address elpher-current-node) image))))))) (elpher-get-node-download))))) ;; Search retrieval (defun elpher-get-search-node () "Getter which submits a search query to the address of the current node." (let* ((address (elpher-node-address elpher-current-node)) (content (elpher-get-cached-content address)) (aborted t)) (if content (progn (elpher-with-clean-buffer (insert content) (elpher-restore-pos)) (message "Displaying cached search results. Reload to perform a new search.")) (unwind-protect (let* ((query-string (read-string "Query: ")) (query-selector (concat (elpher-address-selector address) "\t" query-string)) (search-address (elpher-make-address ?1 query-selector (elpher-address-host address) (elpher-address-port address)))) (setq aborted nil) (elpher-with-clean-buffer (insert "LOADING RESULTS... (use 'u' to cancel)")) (elpher-get-selector search-address (lambda (proc event) (unless (string-prefix-p "deleted" event) (elpher-with-clean-buffer (elpher-insert-index elpher-selector-string)) (goto-char (point-min)) (elpher-cache-content (elpher-node-address elpher-current-node) (buffer-string)))))) (if aborted (elpher-visit-parent-node)))))) ;; Raw server response retrieval (defun elpher-get-node-raw () "Getter which retrieves the raw server response for the current node." (let ((address (elpher-node-address elpher-current-node))) (elpher-with-clean-buffer (insert "LOADING RAW SERVER RESPONSE... (use 'u' to cancel)")) (if address (elpher-get-selector address (lambda (proc event) (unless (string-prefix-p "deleted" event) (elpher-with-clean-buffer (insert elpher-selector-string) (goto-char (point-min)))))) (progn (elpher-with-clean-buffer (insert elpher-start-index)) (goto-char (point-min))))) (message "Displaying raw server response. Reload or redraw to return to standard view.")) ;; File export retrieval (defvar elpher-download-filename) (defun elpher-get-node-download () "Getter which retrieves the current node and writes the result to a file." (let* ((address (elpher-node-address elpher-current-node)) (selector (elpher-address-selector address))) (elpher-visit-parent-node) ; Do first in case of non-local exits. (let* ((filename-proposal (file-name-nondirectory selector)) (filename (read-file-name "Save file as: " nil nil nil (if (> (length filename-proposal) 0) filename-proposal "gopher.file")))) (message "Downloading...") (setq elpher-download-filename filename) (condition-case the-error (elpher-get-selector address (lambda (proc event) (let ((coding-system-for-write 'binary)) (with-temp-file elpher-download-filename (insert elpher-selector-string) (message (format "Download complate, saved to file %s." elpher-download-filename))))) t) (error (error "Error downloading %s" elpher-download-filename)))))) ;; URL retrieval (defun elpher-insert-rendered-html (string) "Use shr to insert rendered view of html STRING into current buffer." (let ((dom (with-temp-buffer (insert string) (libxml-parse-html-region (point-min) (point-max))))) (shr-insert-document dom))) (defun elpher-get-url-node () "Getter which attempts to open the URL specified by the current node." (let* ((address (elpher-node-address elpher-current-node)) (selector (elpher-address-selector address))) (let ((url (elt (split-string selector "URL:") 1))) (if url (progn (elpher-visit-parent-node) ; Do first in case of non-local exits. (message "Opening URL...") (if elpher-open-urls-with-eww (browse-web url) (browse-url url))) (let ((content (elpher-get-cached-content address))) (if content (progn (elpher-with-clean-buffer (insert content) (elpher-restore-pos))) (elpher-with-clean-buffer (insert "LOADING HTML... (use 'u' to cancel)")) (elpher-get-selector address (lambda (proc event) (unless (string-prefix-p "deleted" event) (elpher-with-clean-buffer (elpher-insert-rendered-html elpher-selector-string) (goto-char (point-min)) (elpher-cache-content (elpher-node-address elpher-current-node) (buffer-string)))))))))))) ;; Telnet node connection (defun elpher-get-telnet-node () "Getter which opens a telnet connection to the server specified by the current node." (let* ((address (elpher-node-address elpher-current-node)) (host (elpher-address-host address)) (port (elpher-address-port address))) (elpher-visit-parent-node) (telnet host port))) ;; Start page node retrieval (defun elpher-get-start-node () "Getter which displays the start page." (elpher-with-clean-buffer (elpher-insert-index elpher-start-index) (elpher-restore-pos))) ;; Bookmarks page node retrieval (defun elpher-get-bookmarks-node () "Getter to load and display the current bookmark list." (elpher-with-clean-buffer (insert "---- Bookmark list ----\n\n") (let ((bookmarks (elpher-load-bookmarks))) (if bookmarks (dolist (bookmark bookmarks) (let ((display-string (elpher-bookmark-display-string bookmark)) (address (elpher-bookmark-address bookmark))) (elpher-insert-index-record display-string address))) (insert "No bookmarks found.\n"))) (insert "\n-----------------------\n\n" "- u: return to previous page\n" "- x: delete selected bookmark\n" "- a: rename selected bookmark\n\n" "Bookmarks are stored in the file " (locate-user-emacs-file "elpher-bookmarks")) (elpher-restore-pos))) ;;; Bookmarks ;; (defun elpher-make-bookmark (display-string address) "Make an elpher bookmark. DISPLAY-STRING determines how the bookmark will appear in the bookmark list, while ADDRESS is the address of the entry." (list display-string address)) (defun elpher-bookmark-display-string (bookmark) "Get the display string of BOOKMARK." (elt bookmark 0)) (defun elpher-set-bookmark-display-string (bookmark display-string) "Set the display string of BOOKMARK to DISPLAY-STRING." (setcar bookmark display-string)) (defun elpher-bookmark-address (bookmark) "Get the address for BOOKMARK." (elt bookmark 1)) (defun elpher-save-bookmarks (bookmarks) "Record the bookmark list BOOKMARKS to the user's bookmark file. Beware that this completely replaces the existing contents of the file." (with-temp-file (locate-user-emacs-file "elpher-bookmarks") (erase-buffer) (insert "; Elpher gopher bookmarks file\n\n" "; Bookmarks are stored as a list of (label (type selector host port))\n" "; s-expressions, where type is stored as a character (i.e. 49 = ?1).\n" "; Feel free to edit by hand, but ensure this structure remains intact.\n\n") (pp bookmarks (current-buffer)))) (defun elpher-load-bookmarks () "Get the list of bookmarks from the users's bookmark file." (with-temp-buffer (ignore-errors (insert-file-contents (locate-user-emacs-file "elpher-bookmarks")) (goto-char (point-min)) (read (current-buffer))))) (defun elpher-add-address-bookmark (address display-string) "Save a bookmark for ADDRESS with label DISPLAY-STRING. If ADDRESS is already bookmarked, update the label only." (let ((bookmarks (elpher-load-bookmarks))) (let ((existing-bookmark (rassoc (list address) bookmarks))) (if existing-bookmark (elpher-set-bookmark-display-string existing-bookmark display-string) (add-to-list 'bookmarks (elpher-make-bookmark display-string address)))) (elpher-save-bookmarks bookmarks))) (defun elpher-remove-address-bookmark (address) "Remove any bookmark to ADDRESS." (elpher-save-bookmarks (seq-filter (lambda (bookmark) (not (equal (elpher-bookmark-address bookmark) address))) (elpher-load-bookmarks)))) ;;; Interactive procedures ;; (defun elpher-next-link () "Move point to the next link on the current page." (interactive) (forward-button 1)) (defun elpher-prev-link () "Move point to the previous link on the current page." (interactive) (backward-button 1)) (defun elpher-follow-current-link () "Open the link or url at point." (interactive) (push-button)) (defun elpher-go () "Go to a particular gopher site read from the minibuffer. The site may be specified via a URL or explicitly in terms of host, selector and port." (interactive) (let ((node (let ((host-or-url (read-string "Gopher host or URL: "))) (if (string-match elpher-url-regex host-or-url) (elpher-make-node-from-matched-url host-or-url) (let ((selector (read-string "Selector (default none): " nil nil "")) (port-string (read-string "Port (default 70): " nil nil "70"))) (elpher-make-node (concat "gopher://" host-or-url ":" port-string "/1" selector) (elpher-make-address ?1 selector host-or-url (string-to-number port-string)))))))) (switch-to-buffer "*elpher*") (elpher-visit-node node))) (defun elpher-redraw () "Redraw current page." (interactive) (if elpher-current-node (elpher-visit-node elpher-current-node) (message "No current site."))) (defun elpher-reload () "Reload current page." (interactive) (if elpher-current-node (elpher-reload-current-node) (message "No current site."))) (defun elpher-toggle-tls () "Toggle TLS encryption mode." (interactive) (setq elpher-use-tls (not elpher-use-tls)) (if elpher-use-tls (if (gnutls-available-p) (message "TLS mode enabled. (Will not affect current page until reload.)") (setq elpher-use-tls nil) (error "Cannot enable TLS mode: GnuTLS not available")) (message "TLS mode disabled. (Will not affect current page until reload.)"))) (defun elpher-view-raw () "View raw server response for current page." (interactive) (if elpher-current-node (if (elpher-address-special-p (elpher-node-address elpher-current-node)) (error "This page was not generated by a server") (elpher-visit-node elpher-current-node #'elpher-get-node-raw)) (message "No current site."))) (defun elpher-back () "Go to previous site." (interactive) (if (elpher-node-parent elpher-current-node) (elpher-visit-parent-node) (error "No previous site"))) (defun elpher-download () "Download the link at point." (interactive) (let ((button (button-at (point)))) (if button (let ((node (button-get button 'elpher-node))) (if (elpher-address-special-p (elpher-node-address node)) (error "Cannot download this link") (elpher-visit-node (button-get button 'elpher-node) #'elpher-get-node-download))) (error "No link selected")))) (defun elpher-download-current () "Download the current page." (interactive) (if (elpher-address-special-p (elpher-node-address elpher-current-node)) (error "Cannot download this page") (elpher-visit-node (elpher-make-node (elpher-node-display-string elpher-current-node) (elpher-node-address elpher-current-node) elpher-current-node) #'elpher-get-node-download t))) (defun elpher-build-link-map () "Build alist mapping link names to destination nodes in current buffer." (let ((link-map nil) (b (next-button (point-min) t))) (while b (add-to-list 'link-map (cons (button-label b) b)) (setq b (next-button (button-start b)))) link-map)) (defun elpher-jump () "Select a directory entry by name. Similar to the info browser (m)enu command." (interactive) (let* ((link-map (elpher-build-link-map))) (if link-map (let ((key (let ((completion-ignore-case t)) (completing-read "Directory item/link: " link-map nil t)))) (if (and key (> (length key) 0)) (let ((b (cdr (assoc key link-map)))) (goto-char (button-start b)) (button-activate b))))))) (defun elpher-root-dir () "Visit root of current server." (interactive) (let* ((address (elpher-node-address elpher-current-node)) (host (elpher-address-host address))) (if host (let ((host (elpher-address-host address)) (selector (elpher-address-selector address)) (port (elpher-address-port address))) (if (> (length selector) 0) (let ((root-address (elpher-make-address ?1 "" host port))) (elpher-visit-node (elpher-make-node (concat "gopher://" host ":" (number-to-string port) "/1/") root-address))) (error "Already at root directory of current server"))) (error "Command invalid for this page")))) (defun elpher-bookmarks-current-p () "Return non-nil if current node is a bookmarks page." (eq (elpher-address-type (elpher-node-address elpher-current-node)) 'bookmarks)) (defun elpher-reload-bookmarks () "Reload bookmarks if current node is a bookmarks page." (if (elpher-bookmarks-current-p) (elpher-reload-current-node))) (defun elpher-bookmark-current () "Bookmark the current node." (interactive) (let ((address (elpher-node-address elpher-current-node)) (display-string (elpher-node-display-string elpher-current-node))) (if (not (elpher-address-special-p address)) (let ((bookmark-display-string (read-string "Bookmark display string: " display-string))) (elpher-add-address-bookmark address bookmark-display-string) (message "Bookmark added.")) (error "Cannot bookmark %s" display-string)))) (defun elpher-bookmark-link () "Bookmark the link at point." (interactive) (let ((button (button-at (point)))) (if button (let* ((node (button-get button 'elpher-node)) (address (elpher-node-address node)) (display-string (elpher-node-display-string node))) (if (not (elpher-address-special-p address)) (let ((bookmark-display-string (read-string "Bookmark display string: " display-string))) (elpher-add-address-bookmark address bookmark-display-string) (elpher-reload-bookmarks) (message "Bookmark added.")) (error "Cannot bookmark %s" display-string))) (error "No link selected")))) (defun elpher-unbookmark-current () "Remove bookmark for the current node." (interactive) (let ((address (elpher-node-address elpher-current-node))) (unless (elpher-address-special-p address) (elpher-remove-address-bookmark address) (message "Bookmark removed.")))) (defun elpher-unbookmark-link () "Remove bookmark for the link at point." (interactive) (let ((button (button-at (point)))) (if button (let ((node (button-get button 'elpher-node))) (elpher-remove-address-bookmark (elpher-node-address node)) (elpher-reload-bookmarks) (message "Bookmark removed.")) (error "No link selected")))) (defun elpher-bookmarks () "Visit bookmarks page." (interactive) (switch-to-buffer "*elpher*") (elpher-visit-node (elpher-make-node "Bookmarks Page" (elpher-make-address 'bookmarks)))) (defun elpher-info-node (node) "Display information on NODE." (let ((display-string (elpher-node-display-string node)) (address (elpher-node-address node))) (if (not (elpher-address-special-p address)) (message "`%s' on %s port %s" (elpher-address-selector address) (elpher-address-host address) (elpher-address-port address)) (message "%s" display-string)))) (defun elpher-info-link () "Display information on node corresponding to link at point." (interactive) (let ((button (button-at (point)))) (if button (elpher-info-node (button-get button 'elpher-node)) (error "No item selected")))) (defun elpher-info-current () "Display information on current node." (interactive) (elpher-info-node elpher-current-node)) (defun elpher-get-address-url (address) "Get URL representation of ADDRESS." (let ((type (elpher-address-type address)) (selector (elpher-address-selector address)) (host (elpher-address-host address)) (port (elpher-address-port address))) (if (and (equal type ?h) (string-prefix-p "URL:" selector)) (elt (split-string selector "URL:") 1) (concat "gopher" (if (elpher-address-use-tls-p address) "s" "") "://" host (if (equal port 70) "" (format ":%d" port)) "/" (string type) selector)))) (defun elpher-copy-node-url (node) "Copy URL representation of address of NODE to `kill-ring'." (let ((address (elpher-node-address node))) (if (elpher-address-special-p address) (error (format "Cannot represent %s as URL" (elpher-node-display-string node))) (let ((url (elpher-get-address-url address))) (message "Copied \"%s\" to kill-ring/clipboard." url) (kill-new url))))) (defun elpher-copy-link-url () "Copy URL of item at point to `kill-ring'." (interactive) (let ((button (button-at (point)))) (if button (elpher-copy-node-url (button-get button 'elpher-node)) (error "No item selected")))) (defun elpher-copy-current-url () "Copy URL of current node to `kill-ring'." (interactive) (elpher-copy-node-url elpher-current-node)) (defun elpher-set-coding-system () "Specify an explicit character coding system." (interactive) (let ((system (read-coding-system "Set coding system to use (default is to autodetect): " nil))) (setq elpher-user-coding-system system) (if system (message "Coding system fixed to %s. (Reload to see effect)." system) (message "Coding system set to autodetect. (Reload to see effect).")))) ;;; Mode and keymap ;; (defvar elpher-mode-map (let ((map (make-sparse-keymap))) (define-key map (kbd "TAB") 'elpher-next-link) (define-key map (kbd "") 'elpher-prev-link) (define-key map (kbd "u") 'elpher-back) (define-key map (kbd "O") 'elpher-root-dir) (define-key map (kbd "g") 'elpher-go) (define-key map (kbd "r") 'elpher-redraw) (define-key map (kbd "R") 'elpher-reload) (define-key map (kbd "T") 'elpher-toggle-tls) (define-key map (kbd "w") 'elpher-view-raw) (define-key map (kbd "d") 'elpher-download) (define-key map (kbd "D") 'elpher-download-current) (define-key map (kbd "m") 'elpher-jump) (define-key map (kbd "i") 'elpher-info-link) (define-key map (kbd "I") 'elpher-info-current) (define-key map (kbd "c") 'elpher-copy-link-url) (define-key map (kbd "C") 'elpher-copy-current-url) (define-key map (kbd "a") 'elpher-bookmark-link) (define-key map (kbd "A") 'elpher-bookmark-current) (define-key map (kbd "x") 'elpher-unbookmark-link) (define-key map (kbd "X") 'elpher-unbookmark-current) (define-key map (kbd "B") 'elpher-bookmarks) (define-key map (kbd "S") 'elpher-set-coding-system) (when (fboundp 'evil-define-key) (evil-define-key 'motion map (kbd "TAB") 'elpher-next-link (kbd "C-]") 'elpher-follow-current-link (kbd "C-t") 'elpher-back (kbd "u") 'elpher-back (kbd "O") 'elpher-root-dir (kbd "g") 'elpher-go (kbd "r") 'elpher-redraw (kbd "R") 'elpher-reload (kbd "T") 'elpher-toggle-tls (kbd "w") 'elpher-view-raw (kbd "d") 'elpher-download (kbd "D") 'elpher-download-current (kbd "m") 'elpher-jump (kbd "i") 'elpher-info-link (kbd "I") 'elpher-info-current (kbd "c") 'elpher-copy-link-url (kbd "C") 'elpher-copy-current-url (kbd "a") 'elpher-bookmark-link (kbd "A") 'elpher-bookmark-current (kbd "x") 'elpher-unbookmark-link (kbd "X") 'elpher-unbookmark-current (kbd "B") 'elpher-bookmarks (kbd "S") 'elpher-set-coding-system)) map) "Keymap for gopher client.") (define-derived-mode elpher-mode special-mode "elpher" "Major mode for elpher, an elisp gopher client. This mode is automatically enabled by the interactive functions which initialize the gopher client, namely `elpher', `elpher-go' and `elpher-bookmarks'.") (when (fboundp 'evil-set-initial-state) (evil-set-initial-state 'elpher-mode 'motion)) ;;; Main start procedure ;; ;;;###autoload (defun elpher () "Start elpher with default landing page." (interactive) (if (get-buffer "*elpher*") (switch-to-buffer "*elpher*") (switch-to-buffer "*elpher*") (setq elpher-current-node nil) (let ((start-node (elpher-make-node "Elpher Start Page" (elpher-make-address 'start)))) (elpher-visit-node start-node))) "Started Elpher.") ; Otherwise (elpher) evaluates to start page string. ;;; elpher.el ends here