Updated link to gemini gopher page in README.
[elpher.git] / elpher.el
index 2afe674..474eee1 100644 (file)
--- a/elpher.el
+++ b/elpher.el
@@ -1,13 +1,13 @@
-;;; elpher.el --- A friendly gopher client.
+;;; elpher.el --- A friendly gopher client  -*- lexical-binding:t -*-
 
 ;; Copyright (C) 2019 Tim Vaughan
 
-;; Author: Tim Vaughan <tgvaughan@gmail.com>
+;; Author: Tim Vaughan <timv@ughan.xyz>
 ;; Created: 11 April 2019
-;; Version: 1.4.5
+;; Version: 2.5.2
 ;; Keywords: comm gopher
-;; Homepage: https://github.com/tgvaughan/elpher
-;; Package-Requires: ((emacs "25"))
+;; Homepage: http://thelambdalab.xyz/elpher
+;; Package-Requires: ((emacs "26"))
 
 ;; This file is not part of GNU Emacs.
 
@@ -36,7 +36,8 @@
 ;; - pleasant and configurable colouring of Gopher directories,
 ;; - direct visualisation of image files,
 ;; - a simple bookmark management system,
-;; - connections using TLS encryption.
+;; - connections using TLS encryption,
+;; - the fledgling Gemini protocol.
 
 ;; To launch Elpher, simply use 'M-x elpher'.  This will open a start
 ;; page containing information on key bindings and suggested starting
 ;; Full instructions can be found in the Elpher info manual.
 
 ;; Elpher is under active development.  Any suggestions for
-;; improvements are welcome!
+;; improvements are welcome, and can be made on the official
+;; project page, gopher://thelambdalab.xyz/1/projects/elpher/.
 
 ;;; Code:
 
 (provide 'elpher)
+
+;;; Dependencies
+;;
+
 (require 'seq)
 (require 'pp)
 (require 'shr)
+(require 'url-util)
+(require 'subr-x)
+(require 'dns)
+(require 'ansi-color)
+
 
 ;;; Global constants
 ;;
 
-(defconst elpher-version "1.4.5"
+(defconst elpher-version "2.5.2"
   "Current version of elpher.")
 
 (defconst elpher-margin-width 6
   "Width of left-hand margin used when rendering indicies.")
 
-
 (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 "url" 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.")
+  '(((gopher ?0) elpher-get-gopher-page elpher-render-text "txt" elpher-text)
+    ((gopher ?1) elpher-get-gopher-page elpher-render-index "/" elpher-index)
+    ((gopher ?4) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
+    ((gopher ?5) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
+    ((gopher ?7) elpher-get-gopher-query-page elpher-render-index "?" elpher-search)
+    ((gopher ?9) elpher-get-gopher-page elpher-render-download "bin" elpher-binary)
+    ((gopher ?g) elpher-get-gopher-page elpher-render-image "img" elpher-image)
+    ((gopher ?p) elpher-get-gopher-page elpher-render-image "img" elpher-image)
+    ((gopher ?I) elpher-get-gopher-page elpher-render-image "img" elpher-image)
+    ((gopher ?d) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
+    ((gopher ?P) elpher-get-gopher-page elpher-render-download "doc" elpher-binary)
+    ((gopher ?s) elpher-get-gopher-page elpher-render-download "snd" elpher-binary)
+    ((gopher ?h) elpher-get-gopher-page elpher-render-html "htm" elpher-html)
+    (gemini elpher-get-gemini-page elpher-render-gemini "gem" elpher-gemini)
+    (telnet elpher-get-telnet-page nil "tel" elpher-telnet)
+    (other-url elpher-get-other-url-page nil "url" elpher-other-url)
+    ((special bookmarks) elpher-get-bookmarks-page nil "/" elpher-index)
+    ((special start) elpher-get-start-page nil))
+  "Association list from types to getters, renderers, margin codes and index faces.")
 
 
 ;;; Customization group
   '((t :inherit warning))
   "Face used for search type directory records.")
 
-(defface elpher-url
+(defface elpher-html
   '((t :inherit font-lock-comment-face))
-  "Face used for url type directory records.")
+  "Face used for html type directory records.")
+
+(defface elpher-gemini
+  '((t :inherit font-lock-regexp-grouping-backslash))
+  "Face used for html type directory records.")
+
+(defface elpher-other-url
+  '((t :inherit font-lock-comment-face))
+  "Face used for other URL type links records.")
 
 (defface elpher-telnet
   '((t :inherit font-lock-function-name-face))
 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."
+  "If non-nil, display current page information in buffer header."
   :type '(boolean))
 
 (defcustom elpher-auto-disengage-TLS nil
@@ -160,77 +174,143 @@ 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))
 
+(defcustom elpher-connection-timeout 5
+  "Specifies the number of seconds to wait for a network connection to time out."
+  :type '(integer))
+
+(defcustom elpher-filter-ansi-from-text nil
+  "If non-nil, filter ANSI escape sequences from text.
+The default behaviour is to use the ansi-color package to interpret these
+sequences."
+  :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)))
+;; An elpher "address" object is either a url object or a symbol.
+;; Symbol addresses are "special", corresponding to pages generated
+;; dynamically for and by elpher.  All others represent pages which
+;; rely on content retrieved over the network.
+
+(defun elpher-address-from-url (url-string)
+  "Create a ADDRESS object corresponding to the given URL-STRING."
+  (let ((data (match-data))) ; Prevent parsing clobbering match data
+    (unwind-protect
+        (let ((url (url-generic-parse-url url-string)))
+          (unless (and (not (url-fullness url)) (url-type url))
+            (setf (url-fullness url) t)
+            (setf (url-filename url)
+                  (url-unhex-string (url-filename url)))
+            (unless (url-type url)
+              (setf (url-type url) "gopher"))
+            (when (or (equal "gopher" (url-type url))
+                      (equal "gophers" (url-type url)))
+              ;; Gopher defaults
+              (unless (url-host url)
+                (setf (url-host url) (url-filename url))
+                (setf (url-filename url) ""))
+              (when (or (equal (url-filename url) "")
+                        (equal (url-filename url) "/"))
+                (setf (url-filename url) "/1")))
+            (when (equal "gemini" (url-type url))
+              ;; Gemini defaults
+              (if (equal (url-filename url) "")
+                  (setf (url-filename url) "/"))))
+          url)
+      (set-match-data data))))
+
+(defun elpher-make-gopher-address (type selector host port &optional tls)
+  "Create an ADDRESS object using gopher directory record attributes.
+The basic attributes include: TYPE, SELECTOR, HOST and PORT.
+If the optional attribute TLS is non-nil, the address will be marked as
+requiring gopher-over-TLS."
+  (cond
+   ((and (equal type ?h)
+         (string-prefix-p "URL:" selector))
+    (elpher-address-from-url (elt (split-string selector "URL:") 1)))
+   ((equal type ?8)
+    (elpher-address-from-url
+     (concat "telnet"
+             "://" host
+             ":" (number-to-string port))))
+   (t
+    (elpher-address-from-url
+     (concat "gopher" (if tls "s" "")
+             "://" host
+             ":" (number-to-string port)
+             "/" (string type)
+             selector)))))
+
+(defun elpher-make-special-address (type)
+  "Create an ADDRESS object corresponding to the given special address symbol TYPE."
+  type)
+
+(defun elpher-address-to-url (address)
+  "Get string representation of ADDRESS, or nil if ADDRESS is special."
+  (if (not (elpher-address-special-p address))
+      (url-encode-url (url-recreate-url address))
+    nil))
 
 (defun elpher-address-type (address)
-  "Retrieve type from ADDRESS."
-  (elt address 0))
-
-(defun elpher-address-selector (address)
-  "Retrieve selector from ADDRESS."
-  (elt address 1))
+  "Retrieve type of ADDRESS object.
+This is used to determine how to retrieve and render the document the
+address refers to, via the table `elpher-type-map'."
+  (if (symbolp address)
+      (list 'special address)
+    (let ((protocol (url-type address)))
+      (cond ((or (equal protocol "gopher")
+                 (equal protocol "gophers"))
+             (list 'gopher
+                   (if (member (url-filename address) '("" "/"))
+                       ?1
+                     (string-to-char (substring (url-filename address) 1)))))
+            ((equal protocol "gemini")
+             'gemini)
+            ((equal protocol "telnet")
+             'telnet)
+            (t 'other-url)))))
+
+(defun elpher-address-protocol (address)
+  "Retrieve the transport protocol for ADDRESS.  This is nil for special addresses."
+  (if (symbolp address)
+      nil
+    (url-type address)))
+
+(defun elpher-address-filename (address)
+  "Retrieve the filename component of ADDRESS.
+For gopher addresses this is a combination of the selector type and selector."
+  (if (symbolp address)
+      nil
+    (url-filename address)))
 
 (defun elpher-address-host (address)
-  "Retrieve host from ADDRESS."
-  (elt address 2))
+  "Retrieve host from ADDRESS object."
+  (url-host address))
 
 (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))
+  "Retrieve port from ADDRESS object.
+If no address is defined, returns 0.  (This is for compatibility with the URL library.)"
+  (if (symbolp address)
+      0
+    (url-port address)))
 
 (defun elpher-address-special-p (address)
-  "Return non-nil if ADDRESS is special (e.g. start page, bookmarks page)."
-  (not (elpher-address-host address)))
+  "Return non-nil if ADDRESS object is special (e.g. start page, bookmarks page)."
+  (symbolp address))
 
-;; Node
+(defun elpher-address-gopher-p (address)
+  "Return non-nill if ADDRESS object is a gopher address."
+  (and (not (elpher-address-special-p address))
+       (member (elpher-address-protocol address) '("gopher gophers"))))
 
-(defun elpher-make-node (display-string address &optional parent)
-  "Create a node in the gopher page hierarchy.
+(defun elpher-gopher-address-selector (address)
+  "Retrieve gopher selector from ADDRESS object."
+  (if (member (url-filename address) '("" "/"))
+      ""
+    (substring (url-filename address) 2)))
 
-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
 
@@ -253,48 +333,72 @@ initially."
   "Set the cursor position cache for ADDRESS to POS."
   (puthash address pos elpher-pos-cache))
 
-;; Node graph traversal
 
-(defvar elpher-current-node nil)
+;; Page
+
+(defun elpher-make-page (display-string address)
+  "Create a page with DISPLAY-STRING and ADDRESS."
+  (list display-string address))
+
+(defun elpher-page-display-string (page)
+  "Retrieve the display string corresponding to PAGE."
+  (elt page 0))
 
-(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."
+(defun elpher-page-address (page)
+  "Retrieve the address corresponding to PAGE."
+  (elt page 1))
+
+(defvar elpher-current-page nil)
+(defvar elpher-history nil)
+
+(defun elpher-visit-page (page &optional renderer no-history)
+  "Visit PAGE using its own renderer or RENDERER, if non-nil.
+Additionally, push PAGE onto the stack of previously-visited pages,
+unless NO-HISTORY 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))))
+  (unless (or no-history
+              (equal (elpher-page-address elpher-current-page)
+                     (elpher-page-address page)))
+    (push elpher-current-page elpher-history))
+  (setq elpher-current-page page)
+  (let* ((address (elpher-page-address page))
+         (type (elpher-address-type address))
+         (type-record (cdr (assoc type elpher-type-map))))
+    (if type-record
+        (funcall (car type-record)
+                 (if renderer
+                     renderer
+                   (cadr type-record)))
+      (elpher-visit-previous-page)
+      (pcase type
+        (`(gopher ,type-char)
+         (error "Unsupported gopher selector type '%c' for '%s'"
+                type-char (elpher-address-to-url address)))
+        (other
+         (error "Unsupported address type '%S' for '%s'"
+                other (elpher-address-to-url address)))))))
+
+(defun elpher-visit-previous-page ()
+  "Visit the previous page in the history."
+  (let ((previous-page (pop elpher-history)))
+    (if previous-page
+        (elpher-visit-page previous-page nil t)
+      (error "No previous page."))))
       
-(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-reload-current-page ()
+  "Reload the current page, discarding any existing cached content."
+  (elpher-cache-content (elpher-page-address elpher-current-page) nil)
+  (elpher-visit-page elpher-current-page))
 
 (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))))
+  "Save the current position of point to the current page."
+  (when elpher-current-page
+    (elpher-cache-pos (elpher-page-address elpher-current-page) (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))))
+  "Restore the position of point to that cached in the current page."
+  (let ((pos (elpher-get-cached-pos (elpher-page-address elpher-current-page))))
     (if pos
         (goto-char pos)
       (goto-char (point-min)))))
@@ -304,9 +408,18 @@ unless PRESERVE-PARENT is non-nil."
 ;;
 
 (defun elpher-update-header ()
-  "If `elpher-use-header' is true, display current node info in window header."
+  "If `elpher-use-header' is true, display current page info in window header."
   (if elpher-use-header
-      (setq header-line-format (elpher-node-display-string elpher-current-node))))
+      (let* ((display-string (elpher-page-display-string elpher-current-page))
+             (address (elpher-page-address elpher-current-page))
+             (tls-string (if (and (not (elpher-address-special-p address))
+                                  (member (elpher-address-protocol address)
+                                          '("gophers" "gemini")))
+                             " [TLS encryption]"
+                           ""))
+             (header (concat display-string
+                             (propertize tls-string 'face 'bold))))
+        (setq header-line-format header))))
 
 (defmacro elpher-with-clean-buffer (&rest args)
   "Evaluate ARGS with a clean *elpher* buffer as current."
@@ -338,26 +451,144 @@ away CRs and any terminating period."
   (elpher-decode (replace-regexp-in-string "\n\.\n$" "\n"
                                            (replace-regexp-in-string "\r" "" string))))
 
-;;; Index rendering
+
+;;; Network error reporting
 ;;
 
+(defun elpher-network-error (address error)
+  "Display ERROR message following unsuccessful negotiation with ADDRESS.
+ERROR can be either an error object or a string."
+  (elpher-with-clean-buffer
+   (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
+           "When attempting to retrieve " (elpher-address-to-url address) ":\n"
+           (if (stringp error) error (error-message-string error)) "\n"
+           (propertize "\n----------------\n\n" 'face 'error)
+           "Press 'u' to return to the previous page.")))
+
+
+;;; Gopher selector retrieval
+;;
+
+(defvar elpher-network-timer nil
+  "Timer used for network connections.")
+
+(defun elpher-process-cleanup ()
+  "Immediately shut down any extant elpher process and timers."
+  (let ((p (get-process "elpher-process")))
+    (if p (delete-process p)))
+  (if (timerp elpher-network-timer)
+      (cancel-timer elpher-network-timer)))
+
+(defvar elpher-use-tls nil
+  "If non-nil, use TLS to communicate with gopher servers.")
+
+(defun elpher-get-selector (address renderer &optional force-ipv4)
+  "Retrieve selector specified by ADDRESS, then render it using RENDERER.
+If FORCE-IPV4 is non-nil, explicitly look up and use IPv4 address corresponding
+to ADDRESS."
+  (when (equal (elpher-address-protocol address) "gophers")
+    (if (gnutls-available-p)
+        (when (not elpher-use-tls)
+          (setq elpher-use-tls t)
+          (message "Engaging TLS gopher mode."))
+      (error "Cannot retrieve TLS gopher selector: GnuTLS not available")))
+  (unless (< (elpher-address-port address) 65536)
+    (error "Cannot retrieve gopher selector: port number > 65536"))
+  (condition-case nil
+      (let* ((kill-buffer-query-functions nil)
+             (port (elpher-address-port address))
+             (host (elpher-address-host address))
+             (selector-string "")
+             (proc (open-network-stream "elpher-process"
+                                        nil
+                                        (if force-ipv4 (dns-query host) host)
+                                        (if (> port 0) port 70)
+                                        :type (if elpher-use-tls 'tls 'plain)
+                                        :nowait t))
+             (timer (run-at-time elpher-connection-timeout
+                                 nil
+                                 (lambda ()
+                                   (pcase (process-status proc)
+                                     ('failed
+                                      (if (and (not (equal (elpher-address-protocol address)
+                                                           "gophers"))
+                                               elpher-use-tls
+                                               (or elpher-auto-disengage-TLS
+                                                   (yes-or-no-p "Could not establish encrypted connection.  Disable TLS mode?")))
+                                          (progn
+                                            (message "Disabling TLS mode.")
+                                            (setq elpher-use-tls nil)
+                                            (elpher-get-selector address renderer))
+                                        (elpher-network-error address "Could not establish encrypted connection")))
+                                     ('connect
+                                      (elpher-process-cleanup)
+                                      (unless force-ipv4
+                                        (message "Connection timed out. Retrying with IPv4 address.")
+                                        (elpher-get-selector address renderer t))))))))
+        (setq elpher-network-timer timer)
+        (set-process-coding-system proc 'binary)
+        (set-process-filter proc
+                            (lambda (_proc string)
+                              (cancel-timer timer)
+                              (setq selector-string
+                                    (concat selector-string string))))
+        (set-process-sentinel proc
+                              (lambda (_proc event)
+                                (condition-case the-error
+                                    (cond
+                                     ((string-prefix-p "deleted" event))
+                                     ((string-prefix-p "open" event)
+                                      (let ((inhibit-eol-conversion t))
+                                        (process-send-string
+                                         proc
+                                         (concat (elpher-gopher-address-selector address)
+                                                 "\r\n"))))
+                                     (t
+                                      (cancel-timer timer)
+                                      (funcall renderer selector-string)
+                                      (elpher-restore-pos)))
+                                  (error
+                                   (elpher-network-error address the-error))))))
+    (error
+     (error "Error initiating connection to server"))))
+
+(defun elpher-get-gopher-page (renderer)
+  "Getter function for gopher pages.
+The RENDERER procedure is used to display the contents of the page
+once they are retrieved from the gopher server."
+  (let* ((address (elpher-page-address elpher-current-page))
+         (content (elpher-get-cached-content address)))
+    (if (and content (funcall renderer nil))
+        (elpher-with-clean-buffer
+         (insert content)
+         (elpher-restore-pos))
+      (elpher-with-clean-buffer
+       (insert "LOADING... (use 'u' to cancel)"))
+      (condition-case the-error
+          (elpher-get-selector address renderer)
+        (error
+         (elpher-network-error address the-error))))))
+
+;; 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))))))
+      (ignore-errors
+        (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-gopher-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."
@@ -371,383 +602,472 @@ away CRs and any terminating period."
         (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-page-button-help (page)
+  "Return a string containing the help text for a button corresponding to PAGE."
+  (let ((address (elpher-page-address page)))
+    (format "mouse-1, RET: open '%s'" (if (elpher-address-special-p address)
+                                          address
+                                        (elpher-address-to-url address)))))
 
-(defun elpher-insert-index-record (display-string address)
+(defun elpher-insert-index-record (display-string &optional 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)))
+The contents of the record are dictated by DISPLAY-STRING and ADDRESS.
+If ADDRESS is not supplied or nil the record is rendered as an
+'information' line."
+  (let* ((type (if address (elpher-address-type address) nil))
+         (type-map-entry (cdr (assoc 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)))
+        (let* ((margin-code (elt type-map-entry 2))
+               (face (elt type-map-entry 3))
+               (filtered-display-string (ansi-color-filter-apply display-string))
+               (page (elpher-make-page filtered-display-string address)))
           (elpher-insert-margin margin-code)
-          (insert-text-button display-string
+          (insert-text-button filtered-display-string
                               'face face
-                              'elpher-node node
+                              'elpher-page page
                               'action #'elpher-click-link
                               'follow-link t
-                              'help-echo (elpher-node-button-help node)))
+                              'help-echo (elpher-page-button-help page)))
       (pcase type
-        (?i ;; Information
+        ((or '(gopher ?i) 'nil) ;; 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) "?"))
+         (let ((propertized-display-string
+                (propertize display-string 'face 'elpher-info)))
+           (insert (elpher-process-text-for-display propertized-display-string))))
+        (`(gopher ,selector-type) ;; Unknown
+         (elpher-insert-margin (concat (char-to-string selector-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)
+  (let ((page (button-get button 'elpher-page)))
+    (elpher-visit-page page)))
 
-(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 â€˜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-render-index (data &optional _mime-type-string)
+  "Render DATA as an index.  MIME-TYPE-STRING is unused."
+  (elpher-with-clean-buffer
+   (if (not data)
+       t
+     (elpher-insert-index data)
+     (elpher-cache-content (elpher-page-address elpher-current-page)
+                           (buffer-string)))))
 
-(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
+;; Text rendering
 
 (defconst elpher-url-regex
-  "\\([a-zA-Z]+\\)://\\([a-zA-Z0-9.\-]+\\)\\(?3::[0-9]+\\)?\\(?4:/[^ \r\n\t(),]*\\)?"
+  "\\([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\-_~?/@|#]\\)?\\)?"
   "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)))
+      (let ((page (elpher-make-page (substring-no-properties (match-string 0))
+                                    (elpher-address-from-url (match-string 0)))))
           (make-text-button (match-beginning 0)
                             (match-end 0)
-                            'elpher-node  node
+                            'elpher-page  page
                             'action #'elpher-click-link
                             'follow-link t
-                            'help-echo (elpher-node-button-help node))))
+                            'help-echo (elpher-page-button-help page)
+                            'face 'button)))
     (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))))))))))
+(defconst elpher-ansi-regex "\x1b\\[[^m]*m"
+  "Wildly incomplete regexp used to strip out some troublesome ANSI escape sequences.")
+
+(defun elpher-process-text-for-display (string)
+  "Perform any desired processing of STRING prior to display as text.
+Currently includes buttonifying URLs and processing ANSI escape codes."
+  (elpher-buttonify-urls (if elpher-filter-ansi-from-text
+                             (ansi-color-filter-apply string)
+                           (ansi-color-apply string))))
+
+(defun elpher-render-text (data &optional _mime-type-string)
+  "Render DATA as text.  MIME-TYPE-STRING is unused."
+  (elpher-with-clean-buffer
+   (if (not data)
+       t
+     (insert (elpher-process-text-for-display (elpher-preprocess-text-response data)))
+     (elpher-cache-content
+      (elpher-page-address elpher-current-page)
+      (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
+(defun elpher-render-image (data &optional _mime-type-string)
+  "Display DATA as image.  MIME-TYPE-STRING is unused."
+  (if (not data)
+      nil
+    (if (display-images-p)
         (progn
-          (elpher-with-clean-buffer
-           (insert-image content)
-           (elpher-restore-pos)))
-      (if (display-images-p)
-          (progn
+          (let ((image (create-image
+                        data
+                        nil t)))
             (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."))
+             (insert-image image)
+             (elpher-restore-pos))))
+      (elpher-render-download data))))
+
+;; Search retrieval and rendering
+
+(defun elpher-get-gopher-query-page (renderer)
+  "Getter for gopher addresses requiring input.
+The response is rendered using the rendering function RENDERER."
+   (let* ((address (elpher-page-address elpher-current-page))
+          (content (elpher-get-cached-content address))
+          (aborted t))
+    (if (and content (funcall renderer nil))
+        (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))))
+                 (query-selector (concat (elpher-gopher-address-selector address) "\t" query-string))
+                 (search-address (elpher-make-gopher-address ?1
+                                                             query-selector
+                                                             (elpher-address-host address)
+                                                             (elpher-address-port address)
+                                                             (equal (elpher-address-type address) "gophers"))))
             (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))))))
+            (elpher-get-selector search-address renderer))
         (if aborted
-            (elpher-visit-parent-node))))))
-
-;; Raw server response retrieval
+            (elpher-visit-previous-page))))))
+;; Raw server response rendering
 
-(defun elpher-get-node-raw ()
-  "Getter which retrieves the raw server response for the current node."
-  (let ((address (elpher-node-address elpher-current-node)))
+(defun elpher-render-raw (data &optional mime-type-string)
+  "Display raw DATA in buffer.  MIME-TYPE-STRING is also displayed if provided."
+  (if (not data)
+      nil
     (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)))
+     (when mime-type-string
+       (insert "MIME type specified by server: '" mime-type-string "'\n"))
+     (insert data)
+     (goto-char (point-min)))
+    (message "Displaying raw server response.  Reload or redraw to return to standard view.")))
+
+;; File save "rendering"
+
+(defun elpher-render-download (data &optional _mime-type-string)
+  "Save DATA to file.  MIME-TYPE-STRING is unused."
+  (if (not data)
+      nil
+    (let* ((address (elpher-page-address elpher-current-page))
+           (selector (elpher-gopher-address-selector address)))
+      (elpher-visit-previous-page) ; Do first in case of non-local exits.
+      (let* ((filename-proposal (file-name-nondirectory selector))
+             (filename (read-file-name "Download complete. Save file as: "
+                                       nil nil nil
+                                       (if (> (length filename-proposal) 0)
+                                           filename-proposal
+                                         "download.file"))))
+        (let ((coding-system-for-write 'binary))
+          (with-temp-file filename
+            (insert data)))
+        (message (format "Saved to file %s." filename))))))
+
+;; HTML rendering
+
+(defun elpher-render-html (data &optional _mime-type-string)
+  "Render DATA as HTML using shr.  MIME-TYPE-STRING is unused."
+  (elpher-with-clean-buffer
+   (if (not data)
+       t
+     (let ((dom (with-temp-buffer
+                  (insert data)
+                  (libxml-parse-html-region (point-min) (point-max)))))
+       (shr-insert-document dom)))))
+
+;; Gemini page retrieval
+
+(defvar elpher-gemini-redirect-chain)
+
+(defun elpher-get-gemini-response (address renderer &optional force-ipv4)
+  "Retrieve gemini ADDRESS, then render using RENDERER.
+If FORCE-IPV4 is non-nil, explicitly look up and use IPv4 address corresponding
+to ADDRESS."
+  (if (not (gnutls-available-p))
+      (error "Cannot establish gemini connection: GnuTLS not available")
+    (unless (< (elpher-address-port address) 65536)
+      (error "Cannot establish gemini connection: port number > 65536"))
+    (condition-case nil
+        (let* ((kill-buffer-query-functions nil)
+               (port (elpher-address-port address))
+               (host (elpher-address-host address))
+               (response-string "")
+               (proc (open-network-stream "elpher-process"
+                                          nil
+                                          (if force-ipv4 (dns-query host) host)
+                                          (if (> port 0) port 1965)
+                                          :type 'tls
+                                          :nowait t))
+               (timer (run-at-time elpher-connection-timeout nil
+                                   (lambda ()
+                                     (elpher-process-cleanup)
+                                     (unless force-ipv4
+                                        ; Try again with IPv4
+                                       (message "Connection timed out.  Retrying with IPv4.")
+                                       (elpher-get-gemini-response address renderer t))))))
+          (setq elpher-network-timer timer)
+          (set-process-coding-system proc 'binary)
+          (set-process-filter proc
+                              (lambda (_proc string)
+                                (when timer
+                                  (cancel-timer timer)
+                                  (setq timer nil))
+                                (setq response-string
+                                      (concat response-string string))))
+          (set-process-sentinel proc
+                                (lambda (proc event)
+                                  (condition-case the-error
+                                      (cond
+                                       ((string-prefix-p "open" event)    ; request URL
+                                        (let ((inhibit-eol-conversion t))
+                                          (process-send-string
+                                           proc
+                                           (concat (elpher-address-to-url address)
+                                                   "\r\n"))))
+                                       ((string-prefix-p "deleted" event)) ; do nothing
+                                       ((and (string-empty-p response-string)
+                                             (not force-ipv4))
+                                        ; Try again with IPv4
+                                        (message "Connection failed. Retrying with IPv4.")
+                                        (cancel-timer timer)
+                                        (elpher-get-gemini-response address renderer t))
+                                       (t
+                                        (funcall #'elpher-process-gemini-response
+                                                 response-string
+                                                 renderer)
+                                        (elpher-restore-pos)))
+                                    (error
+                                           (elpher-network-error address the-error))))))
+      (error
+       (error "Error initiating connection to server")))))
+
+(defun elpher-parse-gemini-response (response)
+  "Parse the RESPONSE string and return a list of components.
+The list is of the form (code meta body).  A response of nil implies
+that the response was malformed."
+  (let ((header-end-idx (string-match "\r\n" response)))
+    (if header-end-idx
+        (let ((header (string-trim (substring response 0 header-end-idx)))
+              (body (substring response (+ header-end-idx 2))))
+          (if (>= (length header) 2)
+              (let ((code (substring header 0 2))
+                    (meta (string-trim (substring header 2))))
+                (list code meta body))
+            (error "Malformed response: No response status found in header %s" header)))
+      (error "Malformed response: No CRLF-delimited header found"))))
+
+(defun elpher-process-gemini-response (response-string renderer)
+  "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
+  (let ((response-components (elpher-parse-gemini-response response-string)))
+    (let ((response-code (elt response-components 0))
+          (response-meta (elt response-components 1))
+          (response-body (elt response-components 2)))
+      (pcase (elt response-code 0)
+        (?1 ; Input required
+         (elpher-with-clean-buffer
+          (insert "Gemini server is requesting input."))
+         (let* ((query-string (read-string (concat response-meta ": ")))
+                (url (elpher-address-to-url (elpher-page-address elpher-current-page)))
+                (query-address (elpher-address-from-url (concat url "?" query-string))))
+           (elpher-get-gemini-response query-address renderer)))
+        (?2 ; Normal response
+         (funcall renderer response-body response-meta))
+        (?3 ; Redirect
+         (message "Following redirect to %s" response-meta)
+         (if (>= (length elpher-gemini-redirect-chain) 5)
+             (error "More than 5 consecutive redirects followed"))
+         (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
+           (if (member redirect-address elpher-gemini-redirect-chain)
+               (error "Redirect loop detected"))
+           (if (not (string= (elpher-address-protocol redirect-address)
+                             "gemini"))
+               (error "Server tried to automatically redirect to non-gemini URL: %s"
+                      response-meta))
+           (add-to-list 'elpher-gemini-redirect-chain redirect-address)
+           (elpher-get-gemini-response redirect-address renderer)))
+        (?4 ; Temporary failure
+         (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
+                response-code response-meta))
+        (?5 ; Permanent failure
+         (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
+                response-code response-meta))
+        (?6 ; Client certificate required
+         (error "Gemini server requires client certificate (unsupported at this time)"))
+        (_other
+         (error "Gemini server response unknown: %s %s"
+                response-code response-meta))))))
+
+(defun elpher-get-gemini-page (renderer)
+  "Getter which retrieves and renders a Gemini page and renders it using RENDERER."
+  (let* ((address (elpher-page-address elpher-current-page))
+         (content (elpher-get-cached-content address)))
+    (condition-case the-error
+        (if (and content (funcall renderer nil))
             (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))
+              (insert content)
+              (elpher-restore-pos))
+          (elpher-with-clean-buffer
+           (insert "LOADING GEMINI... (use 'u' to cancel)"))
+          (setq elpher-gemini-redirect-chain nil)
+          (elpher-get-gemini-response address renderer))
+      (error
+       (elpher-network-error address the-error)))))
+
+
+(defun elpher-render-gemini (body &optional mime-type-string)
+  "Render gemini response BODY with rendering MIME-TYPE-STRING."
+  (if (not body)
+      t
+    (let* ((mime-type-string* (if (or (not mime-type-string)
+                                      (string-empty-p mime-type-string))
+                                  "text/gemini; charset=utf-8"
+                                mime-type-string))
+           (mime-type-split (split-string mime-type-string* ";" t))
+           (mime-type (string-trim (car mime-type-split)))
+           (parameters (mapcar (lambda (s)
+                                 (let ((key-val (split-string s "=")))
+                                   (list (downcase (string-trim (car key-val)))
+                                         (downcase (string-trim (cadr key-val))))))
+                               (cdr mime-type-split))))
+      (when (string-prefix-p "text/" mime-type)
+        (setq body (decode-coding-string
+                    body
+                    (if (assoc "charset" parameters)
+                        (intern (cadr (assoc "charset" parameters)))
+                      'utf-8)))
+        (setq body (replace-regexp-in-string "\r" "" body)))
+      (pcase mime-type
+        ((or "text/gemini" "")
+         (elpher-render-gemini-map body parameters))
+        ("text/html"
+         (elpher-render-html body))
+        ((pred (string-prefix-p "text/"))
+         (elpher-render-gemini-plain-text body parameters))
+        ((pred (string-prefix-p "image/"))
+         (elpher-render-image body))
+        (_other
+         (error "Unsupported MIME type %S" mime-type))))))
+
+(defun elpher-gemini-get-link-url (line)
+  "Extract the url portion of LINE, a gemini map file link line."
+  (string-trim (elt (split-string (substring line 2)) 0)))
+
+(defun elpher-gemini-get-link-display-string (line)
+  "Extract the display string portion of LINE, a gemini map file link line."
+  (let* ((rest (string-trim (elt (split-string line "=>") 1)))
+         (idx (string-match "[ \t]" rest)))
+    (if idx
+        (string-trim (substring rest (+ idx 1)))
+      "")))
+
+(defun elpher-collapse-dot-sequences (filename)
+  "Collapse dot sequences in FILENAME.
+For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
+  (let* ((path (split-string filename "/"))
+         (path-reversed-normalized
+          (seq-reduce (lambda (a b)
+                        (cond ((and a (equal b "..") (cdr a)))
+                              ((and (not a) (equal b "..")) a) ;leading .. are dropped
+                              ((equal b ".") a)
+                              (t (cons b a))))
+                      path nil)))
+    (string-join (reverse path-reversed-normalized) "/")))
+
+(defun elpher-address-from-gemini-url (url)
+  "Extract address from URL with defaults as per gemini map files."
+  (let ((address (url-generic-parse-url url)))
+    (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
+      (setf (url-fullness address) t)
+      (if (url-host address) ;if there is an explicit host, filenames are absolute
+          (if (string-empty-p (url-filename address))
+              (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
+        (setf (url-host address) (url-host (elpher-page-address elpher-current-page)))
+        (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
+          (setf (url-filename address)
+                (concat (file-name-directory
+                         (url-filename (elpher-page-address elpher-current-page)))
+                        (url-filename address)))))
+      (unless (url-type address)
+        (setf (url-type address) "gemini"))
+      (if (equal (url-type address) "gemini")
+          (setf (url-filename address)
+                (elpher-collapse-dot-sequences (url-filename address)))))
+    address))
+
+(defun elpher-render-gemini-map (data _parameters)
+  "Render DATA as a gemini map file, PARAMETERS is currently unused."
+  (elpher-with-clean-buffer
+   (dolist (line (split-string data "\n"))
+     (if (string-prefix-p "=>" line)
+         (let* ((url (elpher-gemini-get-link-url line))
+                (display-string (elpher-gemini-get-link-display-string line))
+                (address (elpher-address-from-gemini-url url)))
+           (if (> (length display-string) 0)
+               (elpher-insert-index-record display-string address)
+             (elpher-insert-index-record url address)))
+       (elpher-insert-index-record line)))
+   (elpher-cache-content
+    (elpher-page-address elpher-current-page)
+    (buffer-string))))
+
+(defun elpher-render-gemini-plain-text (data _parameters)
+  "Render DATA as plain text file.  PARAMETERS is currently unused."
+  (elpher-with-clean-buffer
+   (insert (elpher-process-text-for-display data))
+   (elpher-cache-content
+    (elpher-page-address elpher-current-page)
+    (buffer-string))))
+
+;; Other URL page opening
+
+(defun elpher-get-other-url-page (renderer)
+  "Getter which attempts to open the URL specified by the current page (RENDERER must be nil)."
+  (when renderer
+    (elpher-visit-previous-page)
+    (error "Command not supported for general URLs"))
+  (let* ((address (elpher-page-address elpher-current-page))
+         (url (elpher-address-to-url address)))
+    (progn
+      (elpher-visit-previous-page) ; Do first in case of non-local exits.
+      (message "Opening URL...")
+      (if elpher-open-urls-with-eww
+          (browse-web url)
+        (browse-url url)))))
+
+;; Telnet page connection
+
+(defun elpher-get-telnet-page (renderer)
+  "Opens a telnet connection to the current page address (RENDERER must be nil)."
+  (when renderer
+    (elpher-visit-previous-page)
+    (error "Command not supported for telnet URLs"))
+  (let* ((address (elpher-page-address elpher-current-page))
          (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-visit-previous-page)
+    (if (> port 0)
+        (telnet host port)
+      (telnet host))))
+
+;; Start page page retrieval
+
+(defun elpher-get-start-page (renderer)
+  "Getter which displays the start page (RENDERER must be nil)."
+  (when renderer
+    (elpher-visit-previous-page)
+    (error "Command not supported for start page"))
   (elpher-with-clean-buffer
    (insert "     --------------------------------------------\n"
            "                Elpher Gopher Client             \n"
@@ -759,9 +1079,10 @@ calls, as is necessary if the match is performed by `string-match'."
            " - TAB/Shift-TAB: next/prev item on current page\n"
            " - RET/mouse-1: open item under cursor\n"
            " - m: select an item on current page by name (autocompletes)\n"
-           " - u: return to previous page\n"
+           " - u/mouse-3: return to previous page\n"
            " - o/O: visit different selector or the root menu of the current server\n"
            " - g: go to a particular gopher address\n"
+           " - d/D: download item under cursor or current page\n"
            " - i/I: info on item under cursor or current page\n"
            " - c/C: copy URL representation of item under cursor or current page\n"
            " - a/A: bookmark the item under cursor or current page\n"
@@ -769,24 +1090,33 @@ calls, as is necessary if the match is performed by `string-match'."
            " - B: visit the bookmarks page\n"
            " - r: redraw current page (using cached contents if available)\n"
            " - R: reload current page (regenerates cache)\n"
-           " - T: toggle TLS mode\n"
-           " - d/D: download item under cursor or current page\n"
-           " - w: display the raw server response for the current page\n"
-           " - S: set an explicit character coding system (default is to autodetect)\n"
+           " - S: set character coding system for gopher (default is to autodetect)\n"
+           " - T: toggle TLS gopher mode\n"
+           " - .: display the raw server response for the current page\n"
            "\n"
            "Start your exploration of gopher space:\n")
    (elpher-insert-index-record "Floodgap Systems Gopher Server"
-                               (elpher-make-address ?1 "" "gopher.floodgap.com" 70))
+                               (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
    (insert "\n"
            "Alternatively, select the following item and enter some search terms:\n")
    (elpher-insert-index-record "Veronica-2 Gopher Search Engine"
-                               (elpher-make-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
+                               (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
+   (insert "\n"
+           "This page contains your bookmarked sites (also visit with B):\n")
+   (elpher-insert-index-record "Your Bookmarks" 'bookmarks)
+   (insert "\n"
+           "For Elpher release news or to leave feedback, visit:\n")
+   (elpher-insert-index-record "The Elpher Project Page"
+                               (elpher-make-gopher-address ?1
+                                                           "/projects/elpher/"
+                                                           "thelambdalab.xyz"
+                                                           70))
    (insert "\n"
            "** Refer to the ")
    (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
      (insert-text-button "Elpher info manual"
                          'face 'link
-                         'action (lambda (button)
+                         'action (lambda (_)
                                    (interactive)
                                    (info "(elpher)"))
                          'follow-link t
@@ -794,40 +1124,54 @@ calls, as is necessary if the match is performed by `string-match'."
    (insert " for the full documentation. **\n")
    (insert (propertize
             (concat "  (This should be available if you have installed Elpher using\n"
-                    "   MELPA. Otherwise you will have to install the manual yourself.)")
+                    "   MELPA. Otherwise you will have to install the manual yourself.)\n")
             'face 'shadow))
    (elpher-restore-pos)))
 
-;; Bookmarks page node retrieval
+;; Bookmarks page page retrieval
 
-(defun elpher-get-bookmarks-node ()
-  "Getter to load and display the current bookmark list."
+(defun elpher-get-bookmarks-page (renderer)
+  "Getter to load and display the current bookmark list (RENDERER must be nil)."
+  (when renderer
+    (elpher-visit-previous-page)
+    (error "Command not supported for bookmarks page"))
   (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)))
+                 (address (elpher-address-from-url (elpher-bookmark-url bookmark))))
              (elpher-insert-index-record display-string address)))
        (insert "No bookmarks found.\n")))
-   (insert "\n-----------------------\n\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"))
+           "- a: rename selected bookmark\n"
+           "\n"
+           "Bookmarks are stored in the file ")
+   (let ((filename (locate-user-emacs-file "elpher-bookmarks"))
+         (help-string "RET,mouse-1: Open bookmarks file in new buffer for editing."))
+     (insert-text-button filename
+                         'face 'link
+                         'action (lambda (_)
+                                   (interactive)
+                                   (find-file filename))
+                         'follow-link t
+                         'help-echo help-string))
+   (insert "\n")
    (elpher-restore-pos)))
   
 
 ;;; Bookmarks
 ;;
 
-(defun elpher-make-bookmark (display-string address)
+(defun elpher-make-bookmark (display-string url)
   "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))
+bookmark list, while URL is the url of the entry."
+  (list display-string url))
   
 (defun elpher-bookmark-display-string (bookmark)
   "Get the display string of BOOKMARK."
@@ -837,7 +1181,7 @@ bookmark list, while ADDRESS is the address of the entry."
   "Set the display string of BOOKMARK to DISPLAY-STRING."
   (setcar bookmark display-string))
 
-(defun elpher-bookmark-address (bookmark)
+(defun elpher-bookmark-url (bookmark)
   "Get the address for BOOKMARK."
   (elt bookmark 1))
 
@@ -846,36 +1190,48 @@ bookmark list, while ADDRESS is the address of the entry."
 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")
+    (insert "; Elpher bookmarks file\n\n"
+            "; Bookmarks are stored as a list of (label URL) items.\n"
+            "; Feel free to edit by hand, but take care to ensure\n"
+            "; the list 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)))))
+  (let ((bookmarks
+         (with-temp-buffer
+           (ignore-errors
+             (insert-file-contents (locate-user-emacs-file "elpher-bookmarks"))
+             (goto-char (point-min))
+             (read (current-buffer))))))
+    (if (and bookmarks (listp (cadar bookmarks)))
+        (progn
+          (message "Reading old bookmark file. (Will be updated on write.)")
+          (mapcar (lambda (old-bm)
+                    (list (car old-bm)
+                          (elpher-address-to-url (apply #'elpher-make-gopher-address
+                                                        (cadr old-bm)))))
+                  bookmarks))
+      bookmarks)))
 
 (defun elpher-add-address-bookmark (address display-string)
-  "Save a bookmark for ADDRESS with label 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)))
+  (let ((bookmarks (elpher-load-bookmarks))
+        (url (elpher-address-to-url address)))
+    (let ((existing-bookmark (rassoc (list url) bookmarks)))
       (if existing-bookmark
           (elpher-set-bookmark-display-string existing-bookmark display-string)
-        (add-to-list 'bookmarks (elpher-make-bookmark display-string address))))
+        (push (elpher-make-bookmark display-string url) bookmarks)))
     (elpher-save-bookmarks bookmarks)))
 
 (defun elpher-remove-address-bookmark (address)
   "Remove any bookmark to ADDRESS."
+  (let ((url (elpher-address-to-url address)))
     (elpher-save-bookmarks
      (seq-filter (lambda (bookmark)
-                   (not (equal (elpher-bookmark-address bookmark) address)))
-                 (elpher-load-bookmarks))))
+                   (not (equal (elpher-bookmark-url bookmark) url)))
+                 (elpher-load-bookmarks)))))
 
 ;;; Interactive procedures
 ;;
@@ -895,110 +1251,90 @@ If ADDRESS is already bookmarked, update the label only."
   (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))))))))
+(defun elpher-go (host-or-url)
+  "Go to a particular gopher site HOST-OR-URL.
+When run interactively HOST-OR-URL is read from the minibuffer."
+  (interactive "sGopher or Gemini URL: ")
+  (let ((page (elpher-make-page host-or-url
+                                (elpher-address-from-url host-or-url))))
     (switch-to-buffer "*elpher*")
-    (elpher-visit-node node)))
+    (elpher-visit-page page)
+    '()))
 
 (defun elpher-go-current ()
   "Go to a particular site read from the minibuffer, initialized with the current URL."
   (interactive)
-  (let ((address (elpher-node-address elpher-current-node)))
+  (let ((address (elpher-page-address elpher-current-page)))
     (if (elpher-address-special-p address)
-        (error "Command not valid for this page")
-      (let ((url (read-string "URL: " (elpher-get-address-url address))))
-        (if (string-match elpher-url-regex url)
-            (let ((new-node (elpher-make-node-from-matched-url url)))
-              (unless (equal (elpher-node-address new-node) address)
-                (elpher-visit-node new-node)))
-          (error "Could not parse URL %s" url))))))
+        (error "Command invalid for this page")
+      (let ((url (read-string "Gopher or Gemini URL: " (elpher-address-to-url address))))
+        (elpher-visit-page (elpher-make-page url (elpher-address-from-url url)))))))
 
 (defun elpher-redraw ()
   "Redraw current page."
   (interactive)
-  (if elpher-current-node
-      (elpher-visit-node elpher-current-node)
-    (message "No current site.")))
+  (elpher-visit-page elpher-current-page))
 
 (defun elpher-reload ()
   "Reload current page."
   (interactive)
-  (if elpher-current-node
-      (elpher-reload-current-node)
-    (message "No current site.")))
+  (elpher-reload-current-page))
 
 (defun elpher-toggle-tls ()
-  "Toggle TLS encryption mode."
+  "Toggle TLS encryption mode for gopher."
   (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.)")
+          (message "TLS gopher 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.)")))
+        (error "Cannot enable TLS gopher mode: GnuTLS not available"))
+    (message "TLS gopher 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.")))
+  (if (elpher-address-special-p (elpher-page-address elpher-current-page))
+      (error "This page was not generated by a server")
+    (elpher-visit-page elpher-current-page
+                       #'elpher-render-raw)))
 
 (defun elpher-back ()
   "Go to previous site."
   (interactive)
-  (if (elpher-node-parent elpher-current-node)
-      (elpher-visit-parent-node)
-    (error "No previous site")))
+  (elpher-visit-previous-page))
 
 (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)))
+        (let ((page (button-get button 'elpher-page)))
+          (if (elpher-address-special-p (elpher-page-address page))
+              (error "Cannot download %s"
+                     (elpher-page-display-string page))
+            (elpher-visit-page (button-get button 'elpher-page)
+                               #'elpher-render-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
+  (if (elpher-address-special-p (elpher-page-address elpher-current-page))
+      (error "Cannot download %s"
+             (elpher-page-display-string elpher-current-page))
+    (elpher-visit-page (elpher-make-page
+                        (elpher-page-display-string elpher-current-page)
+                        (elpher-page-address elpher-current-page))
+                       #'elpher-render-download
                        t)))
 
 (defun elpher-build-link-map ()
-  "Build alist mapping link names to destination nodes in current buffer."
+  "Build alist mapping link names to destination pages 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))
+      (push (cons (button-label b) b) link-map)
       (setq b (next-button (button-start b))))
     link-map))
 
@@ -1018,36 +1354,35 @@ host, selector and port."
 (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"))))
+  (let ((address (elpher-page-address elpher-current-page)))
+    (if (not (elpher-address-special-p address))
+        (if (or (member (url-filename address) '("/" ""))
+                (and (elpher-address-gopher-p address)
+                     (= (length (elpher-gopher-address-selector address)) 0)))
+            (error "Already at root directory of current server")
+          (let ((address-copy (elpher-address-from-url
+                               (elpher-address-to-url address))))
+            (setf (url-filename address-copy) "")
+            (elpher-visit-page
+             (elpher-make-page (elpher-address-to-url address-copy)
+                               address-copy))))
+      (error "Command invalid for %s" (elpher-page-display-string elpher-current-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))
+  "Return non-nil if current page is a bookmarks page."
+  (equal (elpher-address-type (elpher-page-address elpher-current-page))
+         '(special bookmarks)))
 
 (defun elpher-reload-bookmarks ()
-  "Reload bookmarks if current node is a bookmarks page."
+  "Reload bookmarks if current page is a bookmarks page."
   (if (elpher-bookmarks-current-p)
-      (elpher-reload-current-node)))
+      (elpher-reload-current-page)))
 
 (defun elpher-bookmark-current ()
-  "Bookmark the current node."
+  "Bookmark the current page."
   (interactive)
-  (let ((address (elpher-node-address elpher-current-node))
-        (display-string (elpher-node-display-string elpher-current-node)))
+  (let ((address (elpher-page-address elpher-current-page))
+        (display-string (elpher-page-display-string elpher-current-page)))
     (if (not (elpher-address-special-p address))
         (let ((bookmark-display-string (read-string "Bookmark display string: "
                                                     display-string)))
@@ -1060,9 +1395,9 @@ host, selector and port."
   (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)))
+        (let* ((page (button-get button 'elpher-page))
+               (address (elpher-page-address page))
+               (display-string (elpher-page-display-string page)))
           (if (not (elpher-address-special-p address))
               (let ((bookmark-display-string (read-string "Bookmark display string: "
                                                           display-string)))
@@ -1073,9 +1408,9 @@ host, selector and port."
       (error "No link selected"))))
 
 (defun elpher-unbookmark-current ()
-  "Remove bookmark for the current node."
+  "Remove bookmark for the current page."
   (interactive)
-  (let ((address (elpher-node-address elpher-current-node)))
+  (let ((address (elpher-page-address elpher-current-page)))
     (unless (elpher-address-special-p address)
       (elpher-remove-address-bookmark address)
       (message "Bookmark removed."))))
@@ -1085,8 +1420,8 @@ host, selector and port."
   (interactive)
   (let ((button (button-at (point))))
     (if button
-        (let ((node (button-get button 'elpher-node)))
-          (elpher-remove-address-bookmark (elpher-node-address node))
+        (let ((page (button-get button 'elpher-page)))
+          (elpher-remove-address-bookmark (elpher-page-address page))
           (elpher-reload-bookmarks)
           (message "Bookmark removed."))
       (error "No link selected"))))
@@ -1095,58 +1430,36 @@ host, selector and port."
   "Visit bookmarks page."
   (interactive)
   (switch-to-buffer "*elpher*")
-  (elpher-visit-node
-   (elpher-make-node "Bookmarks Page" (elpher-make-address 'bookmarks))))
+  (elpher-visit-page
+   (elpher-make-page "Bookmarks Page" (elpher-make-special-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-page (page)
+  "Display information on PAGE."
+  (let ((display-string (elpher-page-display-string page))
+        (address (elpher-page-address page)))
+    (if (elpher-address-special-p address)
+        (message "Special page: %s" display-string)
+      (message "%s" (elpher-address-to-url address)))))
 
 (defun elpher-info-link ()
-  "Display information on node corresponding to link at point."
+  "Display information on page corresponding to link at point."
   (interactive)
   (let ((button (button-at (point))))
     (if button
-        (elpher-info-node (button-get button 'elpher-node))
+        (elpher-info-page (button-get button 'elpher-page))
       (error "No item selected"))))
   
 (defun elpher-info-current ()
-  "Display information on current node."
+  "Display information on current page."
   (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)))
+  (elpher-info-page elpher-current-page))
+
+(defun elpher-copy-page-url (page)
+  "Copy URL representation of address of PAGE to `kill-ring'."
+  (let ((address (elpher-page-address page)))
     (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)))
+        (error (format "Cannot represent %s as URL" (elpher-page-display-string page)))
+      (let ((url (elpher-address-to-url address)))
         (message "Copied \"%s\" to kill-ring/clipboard." url)
         (kill-new url)))))
 
@@ -1155,22 +1468,23 @@ host, selector and port."
   (interactive)
   (let ((button (button-at (point))))
     (if button
-        (elpher-copy-node-url (button-get button 'elpher-node))
+        (elpher-copy-page-url (button-get button 'elpher-page))
       (error "No item selected"))))
 
 (defun elpher-copy-current-url ()
-  "Copy URL of current node to `kill-ring'."
+  "Copy URL of current page to `kill-ring'."
   (interactive)
-  (elpher-copy-node-url elpher-current-node))
+  (elpher-copy-page-url elpher-current-page))
 
-(defun elpher-set-coding-system ()
-  "Specify an explicit character coding system."
+(defun elpher-set-gopher-coding-system ()
+  "Specify an explicit character coding system for gopher selectors."
   (interactive)
-  (let ((system (read-coding-system "Set coding system to use (default is to autodetect): " nil)))
+  (let ((system (read-coding-system "Set coding system to use for gopher (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)."))))
+        (message "Gopher coding system fixed to %s. (Reload to see effect)." system)
+      (message "Gopher coding system set to autodetect. (Reload to see effect)."))))
+
 
 ;;; Mode and keymap
 ;;
@@ -1180,13 +1494,14 @@ host, selector and port."
     (define-key map (kbd "TAB") 'elpher-next-link)
     (define-key map (kbd "<backtab>") 'elpher-prev-link)
     (define-key map (kbd "u") 'elpher-back)
+    (define-key map [mouse-3] 'elpher-back)
     (define-key map (kbd "O") 'elpher-root-dir)
     (define-key map (kbd "g") 'elpher-go)
     (define-key map (kbd "o") 'elpher-go-current)
     (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 ".") '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)
@@ -1199,20 +1514,20 @@ host, selector and port."
     (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
+    (define-key map (kbd "S") 'elpher-set-gopher-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-") 'elpher-follow-current-link
         (kbd "C-t") 'elpher-back
         (kbd "u") 'elpher-back
-        (kbd "O") 'elpher-root-dir
+        [mouse-3] 'elpher-back
         (kbd "g") 'elpher-go
         (kbd "o") 'elpher-go-current
         (kbd "r") 'elpher-redraw
         (kbd "R") 'elpher-reload
         (kbd "T") 'elpher-toggle-tls
-        (kbd "w") 'elpher-view-raw
+        (kbd ".") 'elpher-view-raw
         (kbd "d") 'elpher-download
         (kbd "D") 'elpher-download-current
         (kbd "m") 'elpher-jump
@@ -1225,7 +1540,7 @@ host, selector and port."
         (kbd "x") 'elpher-unbookmark-link
         (kbd "X") 'elpher-unbookmark-current
         (kbd "B") 'elpher-bookmarks
-        (kbd "S") 'elpher-set-coding-system))
+        (kbd "S") 'elpher-set-gopher-coding-system))
     map)
   "Keymap for gopher client.")
 
@@ -1239,6 +1554,7 @@ functions which initialize the gopher client, namely
 (when (fboundp 'evil-set-initial-state)
   (evil-set-initial-state 'elpher-mode 'motion))
 
+
 ;;; Main start procedure
 ;;
 
@@ -1249,10 +1565,10 @@ functions which initialize the gopher client, namely
   (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)))
+    (setq elpher-current-page nil)
+    (let ((start-page (elpher-make-page "Elpher Start Page"
+                                        (elpher-make-special-address 'start))))
+      (elpher-visit-page start-page)))
   "Started Elpher.") ; Otherwise (elpher) evaluates to start page string.
 
 ;;; elpher.el ends here