elopher.el

   1 ;;; elopher.el --- gopher client
   2
   3 ;;; Commentary:
   4
   5 ;; Simple gopher client in elisp.
   6
   7 ;;; Code:
   8
   9 ;;; Global constants
  10 ;;
  11
  12 (defconst elopher-version "1.0.0"
  13   "Current version of elopher.")
  14
  15 (defconst elopher-margin-width 6
  16   "Width of left-hand margin used when rendering indicies.")
  17
  18 (defconst elopher-start-page
  19   (string-join
  20    (list "i\tfake\tfake\t1"
  21          "i--------------------------------------------\tfake\tfake\t1"
  22          "i          Elopher Gopher Client             \tfake\tfake\t1"
  23          (format "i              version %s\tfake\tfake\t1" elopher-version)
  24          "i--------------------------------------------\tfake\tfake\t1"
  25          "i\tfake\tfake\t1"
  26          "iBasic usage:\tfake\tfake\t1"
  27          "i - tab/shift-tab: next/prev directory entry\tfake\tfake\t1"
  28          "i - RET/mouse-1: open directory entry\tfake\tfake\t1"
  29          "i - u: return to parent directory entry\tfake\tfake\t1"
  30          "i - g: go to a particular site\tfake\tfake\t1"
  31          "i\tfake\tfake\t1"
  32          "iPlaces to start exploring Gopherspace:\tfake\tfake\t1"
  33          "1Floodgap Systems Gopher Server\t\tgopher.floodgap.com\t70"
  34          "1Super-Dimensional Fortress\t\tsdf.org\t70"
  35          "i\tfake\tfake\t1"
  36          "iTest entries:\tfake\tfake\t1"
  37          "pXKCD comic image\t/fun/xkcd/comics/2130/2137/text_entry.png\tgopher.floodgap.com\t70"
  38          "1Test server\t\tlocalhost\t70"
  39          ".")
  40    "\r\n"))
  41
  42
  43 ;;; Customization group
  44 ;;
  45
  46 (defgroup elopher nil
  47   "A simple gopher client."
  48   :group 'applications)
  49
  50 (defcustom elopher-index-face '(foreground-color . "cyan")
  51   "Face used for index records.")
  52 (defcustom elopher-text-face '(foreground-color . "white")
  53   "Face used for text records.")
  54 (defcustom elopher-info-face '(foreground-color . "gray")
  55   "Face used for info records.")
  56 (defcustom elopher-image-face '(foreground-color . "green")
  57   "Face used for image records.")
  58 (defcustom elopher-unknown-face '(foreground-color . "red")
  59   "Face used for unknown record types.")
  60
  61 ;;; Model
  62 ;;
  63
  64 ;; Address
  65
  66 (defun elopher-make-address (selector host port)
  67   (list selector host port))
  68
  69 (defun elopher-address-selector (address)
  70   (car address))
  71
  72 (defun elopher-address-host (address)
  73   (cadr address))
  74
  75 (defun elopher-address-port (address)
  76   (caddr address))
  77
  78 ;; Node
  79
  80 (defun elopher-make-node (parent address getter &optional content)
  81   (list parent address getter content))
  82
  83 (defun elopher-node-parent (node)
  84   (car node))
  85
  86 (defun elopher-node-address (node)
  87   (cadr node))
  88
  89 (defun elopher-node-getter (node)
  90   (caddr node))
  91
  92 (defun elopher-node-content (node)
  93   (cadddr node))
  94
  95 (defvar elopher-start-node (elopher-make-node nil nil #'elopher-get-index-node))
  96 (defvar elopher-current-node)
  97
  98 (defun elopher-set-node-content (node content)
  99   (setcar (elopher-node-content node)
 100           content))
 101
 102 (defun elopher-visit-node (node)
 103   (elopher-prepare-buffer)
 104   (setq elopher-current-node node)
 105   (funcall (elopher-node-getter node)))
 106
 107 (defun elopher-reload-current-node ()
 108   (elopher-prepare-buffer)
 109   (elopher-set-node-content elopher-current-node nil)
 110   (funcall (elopher-node-getter elopher-current-node)))
 111
 112
 113 ;;; Buffer preparation
 114 ;;
 115
 116 (defun elopher-prepare-buffer ()
 117   (switch-to-buffer "*elopher*")
 118   (elopher-mode)
 119   (let ((inhibit-read-only t))
 120     (erase-buffer)))
 121
 122
 123 ;;; Index rendering
 124 ;;
 125
 126 (defun elopher-insert-index (string)
 127   "Inserts the index corresponding to STRING into the current buffer."
 128   (dolist (line (split-string string "\r\n"))
 129     (unless (string-empty-p line)
 130       (elopher-insert-index-record line))))
 131
 132 (defun elopher-insert-margin (&optional type-name)
 133   (if type-name
 134       (progn
 135         (insert (format (concat "%" (number-to-string (- elopher-margin-width 1)) "s")
 136                         (concat
 137                          (propertize "[" 'face '(foreground-color . "blue"))
 138                          (propertize type-name 'face '(foreground-color . "white"))
 139                          (propertize "]" 'face '(foreground-color . "blue")))))
 140         (insert " "))
 141     (insert (make-string elopher-margin-width ?\s))))
 142
 143 (defun elopher-insert-index-record (line)
 144   "Inserts the index record corresponding to LINE into the current buffer."
 145   (let* ((type (elt line 0))
 146          (fields (split-string (substring line 1) "\t"))
 147          (display-string (elt fields 0))
 148          (address (elopher-make-address (elt fields 1) (elt fields 2) (elt fields 3))))
 149     (pcase type
 150       (?i (elopher-insert-margin)
 151           (insert (propertize display-string
 152                               'face elopher-info-face)))
 153       (?0 (elopher-insert-margin "T")
 154           (insert-text-button display-string
 155                               'face elopher-text-face
 156                               'elopher-node (elopher-make-node elopher-current-node
 157                                                                address
 158                                                                #'elopher-get-text-node)
 159                               'action #'elopher-click-link
 160                               'follow-link t))
 161       (?1 (elopher-insert-margin "/")
 162           (insert-text-button display-string
 163                               'face elopher-index-face
 164                               'elopher-node (elopher-make-node elopher-current-node
 165                                                                address
 166                                                                #'elopher-get-index-node)
 167                               'action #'elopher-click-link
 168                               'follow-link t))
 169       (?.) ; Occurs at end of index, can safely ignore.
 170       (tp (elopher-insert-margin (concat (char-to-string tp) "?"))
 171           (insert (propertize display-string
 172                               'face elopher-unknown-face))))
 173     (insert "\n")))
 174
 175
 176 ;;; Selector retrieval (all kinds)
 177 ;;
 178
 179 (defvar elopher-selector-string)
 180
 181 (defun elopher-get-selector (address after)
 182   (setq elopher-selector-string "")
 183   (let ((p (get-process "elopher-process")))
 184     (if p (delete-process p)))
 185   (make-network-process
 186    :name "elopher-process"
 187    :host (elopher-address-host address)
 188    :service (elopher-address-port address)
 189    :filter (lambda (proc string)
 190              (setq elopher-selector-string (concat elopher-selector-string string)))
 191    :sentinel after)
 192   (process-send-string "elopher-process"
 193                        (concat (elopher-address-selector address) "\n")))
 194
 195 ;; Index retrieval
 196
 197 (defun elopher-get-index-node ()
 198   (let ((content (elopher-node-content elopher-current-node))
 199         (address (elopher-node-address elopher-current-node)))
 200     (if content
 201         (insert content)
 202       (if address
 203           (elopher-get-selector address
 204                                 (lambda (proc event)
 205                                   (let ((inhibit-read-only t))
 206                                     (erase-buffer)
 207                                     (elopher-insert-index elopher-selector-string))
 208                                   (elopher-set-node-content elopher-current-node
 209                                                             (buffer-string))))
 210         (let ((inhibit-read-only t))
 211           (erase-buffer)
 212           (elopher-insert-index elopher-start-page))))))
 213
 214 ;; Text retrieval
 215
 216 (defun elopher-get-text-node ()
 217   (let ((content (elopher-node-content elopher-current-node))
 218         (address (elopher-node-address elopher-current-node)))
 219     (if content
 220         (let ((inhibit-read-only t))
 221           (insert content))
 222       (elopher-get-selector address
 223                             (lambda (proc event)
 224                               (let ((inhibit-read-only t))
 225                                 (erase-buffer)
 226                                 (insert elopher-selector-string))
 227                               (elopher-set-node-content elopher-current-node
 228                                                         elopher-selector-string))))))
 229
 230 ;;; Navigation methods
 231 ;;
 232
 233 (defun elopher-next-link ()
 234   (interactive)
 235   (forward-button 1))
 236
 237 (defun elopher-prev-link ()
 238   (interactive)
 239   (backward-button 1))
 240
 241 (defun elopher-click-link (button)
 242   (let ((node (button-get button 'elopher-node)))
 243     (elopher-visit-node node)))
 244
 245 (defun elopher-follow-closest-link ()
 246   (interactive)
 247   (push-button))
 248
 249 (defun elopher-go ()
 250   "Go to a particular gopher site."
 251   (interactive)
 252   (let* ((selector "")
 253          (hostname (read-from-minibuffer "Gopher host: "))
 254          (port 70)
 255          (address (list selector hostname port)))
 256     (elopher-visit-node
 257      (elopher-make-node elopher-current-node
 258                         address
 259                         #'elopher-get-index-node))))
 260
 261 (defun  elopher-reload ()
 262   "Reload current site."
 263   (interactive)
 264   (elopher-reload-current-node))
 265
 266
 267 ;;; Main start procedure
 268 ;;
 269 (defun elopher ()
 270   "Start elopher with default landing page."
 271   (interactive)
 272   (elopher-visit-node elopher-start-node))
 273
 274
 275 ;;; Mode and keymap
 276 ;;
 277
 278 (setq elopher-mode-map
 279   (let ((map (make-sparse-keymap)))
 280     (define-key map (kbd "<tab>") 'elopher-next-link)
 281     (define-key map (kbd "<S-tab>") 'elopher-prev-link)
 282     (define-key map (kbd "u") 'elopher-pop-history)
 283     (define-key map (kbd "g") 'elopher-go)
 284     (define-key map (kbd "r") 'elopher-reload)
 285     (when (require 'evil nil t)
 286       (evil-define-key 'normal map
 287         (kbd "C-]") 'elopher-follow-closest-link
 288         (kbd "C-t") 'elopher-pop-history
 289         (kbd "u") 'elopher-pop-history
 290         (kbd "g") 'elopher-go
 291         (kbd "r") 'elopher-reload))
 292     map))
 293   ;; "Keymap for gopher client.")
 294
 295 (define-derived-mode elopher-mode special-mode "elopher"
 296   "Major mode for elopher, an elisp gopher client.")
 297
 298
 299 ;;; elopher.el ends here