Improved behaviour of history-all/visited-pages.

[elpher.git] / elpher.el

diff --git a/elpher.el b/elpher.el
index 89e594b..014ef6b 100644 (file)
--- a/elpher.el
+++ b/elpher.el
@@ -1,13 +1,28 @@
-;;; elpher.el --- A friendly gopher and gemini client  -*- lexical-binding:t -*-
-
-;; Copyright (C) 2019-2020 Tim Vaughan
+;;; elpher.el --- A friendly gopher and gemini client  -*- lexical-binding: t -*-
+
+;; Copyright (C) 2021 Jens Östlund <jostlund@gmail.com>
+;; Copyright (C) 2021 F. Jason Park <jp@neverwas.me>
+;; Copyright (C) 2021 Christopher Brannon <chris@the-brannons.com>
+;; Copyright (C) 2021 Omar Polo <op@omarpolo.com>
+;; Copyright (C) 2021 Noodles! <nnoodle@chiru.no>
+;; Copyright (C) 2020-2021 Alex Schroeder <alex@gnu.org>
+;; Copyright (C) 2020 Zhiwei Chen <chenzhiwei03@kuaishou.com>
+;; Copyright (C) 2020 condy0919 <condy0919@gmail.com>
+;; Copyright (C) 2020 Alexis <flexibeast@gmail.com>
+;; Copyright (C) 2020 Étienne Deparis <etienne@depar.is>
+;; Copyright (C) 2020 Simon Nicolussi <sinic@sinic.name>
+;; Copyright (C) 2020 Michel Alexandre Salim <michel@michel-slm.name>
+;; Copyright (C) 2020 Koushk Roy <kroy@twilio.com>
+;; Copyright (C) 2020 Vee <vee@vnsf.xyz>
+;; Copyright (C) 2020 Simon South <simon@simonsouth.net>
+;; Copyright (C) 2019-2021 Tim Vaughan <plugd@thelambdalab.xyz>

 
 ;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
 ;; Created: 11 April 2019
 
 ;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
 ;; Created: 11 April 2019

-;; Version: 2.8.0
+;; Version: 3.0.0

 ;; Keywords: comm gopher
 ;; Keywords: comm gopher

-;; Homepage: http://thelambdalab.xyz/elpher
-;; Package-Requires: ((emacs "26.1"))
+;; Homepage: https://thelambdalab.xyz/elpher
+;; Package-Requires: ((emacs "27.1"))

 
 ;; This file is not part of GNU Emacs.
 
 
 ;; This file is not part of GNU Emacs.
 


@@ -35,7 +50,6 @@
 ;; - caching of visited sites,
 ;; - pleasant and configurable colouring of Gopher directories,
 ;; - direct visualisation of image files,
 ;; - caching of visited sites,
 ;; - pleasant and configurable colouring of Gopher directories,
 ;; - direct visualisation of image files,

-;; - a simple bookmark management system,

 ;; - gopher connections using TLS encryption,
 ;; - the fledgling Gemini protocol,
 ;; - the greybeard Finger protocol.
 ;; - gopher connections using TLS encryption,
 ;; - the fledgling Gemini protocol,
 ;; - the greybeard Finger protocol.


@@ -48,7 +62,8 @@
 
 ;; Elpher is under active development.  Any suggestions for
 ;; improvements are welcome, and can be made on the official
 
 ;; Elpher is under active development.  Any suggestions for
 ;; improvements are welcome, and can be made on the official

-;; project page, gopher://thelambdalab.xyz/1/projects/elpher/.
+;; project page, gopher://thelambdalab.xyz/elpher, or via the
+;; project mailing list at https://lists.sr.ht/~michel-slm/elpher.

 
 ;;; Code:
 
 
 ;;; Code:
 


@@ -63,15 +78,33 @@
 (require 'url-util)
 (require 'subr-x)
 (require 'dns)
 (require 'url-util)
 (require 'subr-x)
 (require 'dns)

-(require 'ansi-color)

 (require 'nsm)
 (require 'gnutls)
 (require 'nsm)
 (require 'gnutls)

+(require 'socks)
+
+;;; ANSI colors or XTerm colors
+
+(or (require 'xterm-color nil t)
+    (require 'ansi-color))

 
 

+(defalias 'elpher-color-filter-apply
+  (if (fboundp 'xterm-color-filter)
+      (lambda (s)
+        (let ((_xterm-color-render nil))
+          (xterm-color-filter s)))
+    'ansi-color-filter-apply)
+  "A function to filter out ANSI escape sequences.")
+
+(defalias 'elpher-color-apply
+  (if (fboundp 'xterm-color-filter)
+      'xterm-color-filter
+    'ansi-color-apply)
+  "A function to apply ANSI escape sequences.")

 
 ;;; Global constants
 ;;
 
 
 ;;; Global constants
 ;;
 

-(defconst elpher-version "2.8.0"
+(defconst elpher-version "3.0.0"

   "Current version of elpher.")
 
 (defconst elpher-margin-width 6
   "Current version of elpher.")
 
 (defconst elpher-margin-width 6


@@ -95,23 +128,44 @@
     (finger elpher-get-finger-page elpher-render-text "txt" elpher-text)
     (telnet elpher-get-telnet-page nil "tel" elpher-telnet)
     (other-url elpher-get-other-url-page nil "url" elpher-other-url)
     (finger elpher-get-finger-page elpher-render-text "txt" elpher-text)
     (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))
+    ((special start) elpher-get-start-page nil "E" elpher-index)
+    ((special history) elpher-get-history-page nil "E" elpher-index)
+    ((special visited-pages) elpher-get-visited-pages-page nil "E" elpher-index))

   "Association list from types to getters, renderers, margin codes and index faces.")
 
 
   "Association list from types to getters, renderers, margin codes and index faces.")
 
 

+;;; Internal variables
+;;
+
+;; buffer-local
+(defvar elpher--gemini-page-headings nil
+  "List of headings on the page.")
+
+
+;;; Declarations to avoid compiler warnings.
+;;
+
+(eval-when-compile
+  (defvar bookmark-make-record-function)
+  (declare-function bookmark-store "bookmark")
+  (declare-function org-link-store-props "ol")
+  (declare-function org-link-set-parameters "ol")
+  (defvar thing-at-point-uri-schemes)
+  (defvar mu4e~view-beginning-of-url-regexp))
+
+

 ;;; Customization group
 ;;
 
 (defgroup elpher nil
 ;;; Customization group
 ;;
 
 (defgroup elpher nil

-  "A gopher client."
+  "A gopher and gemini client."

   :group 'applications)
 
 ;; General appearance and customizations
 
 (defcustom elpher-open-urls-with-eww nil
   "If non-nil, open URL selectors using eww.
   :group 'applications)
 
 ;; General appearance and customizations
 
 (defcustom elpher-open-urls-with-eww nil
   "If non-nil, open URL selectors using eww.

-Otherwise, use the system browser via the BROWSE-URL function."
+Otherwise, use the system browser via the `browse-url' function."

   :type '(boolean))
 
 (defcustom elpher-use-header t
   :type '(boolean))
 
 (defcustom elpher-use-header t


@@ -120,8 +174,9 @@ Otherwise, use the system browser via the BROWSE-URL function."
 
 (defcustom elpher-auto-disengage-TLS nil
   "If non-nil, automatically disengage TLS following an unsuccessful connection.
 
 (defcustom elpher-auto-disengage-TLS nil
   "If non-nil, automatically disengage TLS following an unsuccessful connection.

-While enabling this may seem convenient, it is also potentially dangerous as it
-allows switching from an encrypted channel back to plain text without user input."
+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
   :type '(boolean))
 
 (defcustom elpher-connection-timeout 5


@@ -140,6 +195,15 @@ sequences."
 These certificates may be used for establishing authenticated TLS connections."
   :type '(directory))
 
 These certificates may be used for establishing authenticated TLS connections."
   :type '(directory))
 

+(defcustom elpher-openssl-command "openssl"
+  "The command used to launch openssl when generating TLS client certificates."
+  :type '(file))
+
+(defcustom elpher-default-url-type "gopher"
+  "Default URL type (i.e. scheme) to assume if not explicitly given."
+  :type '(choice (const "gopher")
+                 (const "gemini")))
+

 (defcustom elpher-gemini-TLS-cert-checks nil
   "If non-nil, verify gemini server TLS certs using the default security level.
 Otherwise, certificate verification is disabled.
 (defcustom elpher-gemini-TLS-cert-checks nil
   "If non-nil, verify gemini server TLS certs using the default security level.
 Otherwise, certificate verification is disabled.


@@ -164,16 +228,17 @@ May be empty."
   "Specify the string used for bullets when rendering gemini maps."
   :type '(string))
 
   "Specify the string used for bullets when rendering gemini maps."
   :type '(string))
 

-(defcustom elpher-bookmarks-file (locate-user-emacs-file "elpher-bookmarks")
-  "Specify the name of the file where elpher bookmarks will be saved."
-  :type '(file))
-

 (defcustom elpher-ipv4-always nil
   "If non-nil, elpher will always use IPv4 to establish network connections.
 This can be useful when browsing from a computer that supports IPv6, because
 some servers which do not support IPv6 can take a long time to time-out."
   :type '(boolean))
 
 (defcustom elpher-ipv4-always nil
   "If non-nil, elpher will always use IPv4 to establish network connections.
 This can be useful when browsing from a computer that supports IPv6, because
 some servers which do not support IPv6 can take a long time to time-out."
   :type '(boolean))
 

+(defcustom elpher-socks-always nil
+  "If non-nil, elpher will establish network connections over a SOCKS proxy.
+Otherwise, the SOCKS proxy is only used for connections to onion services."
+  :type '(boolean))
+

 ;; Face customizations
 
 (defgroup elpher-faces nil
 ;; Face customizations
 
 (defgroup elpher-faces nil


@@ -205,7 +270,7 @@ some servers which do not support IPv6 can take a long time to time-out."
   "Face used for html type directory records.")
 
 (defface elpher-gemini
   "Face used for html type directory records.")
 
 (defface elpher-gemini

-  '((t :inherit font-lock-regexp-grouping-backslash))
+  '((t :inherit font-lock-constant-face))

   "Face used for Gemini type directory records.")
 
 (defface elpher-other-url
   "Face used for Gemini type directory records.")
 
 (defface elpher-other-url


@@ -248,6 +313,10 @@ some servers which do not support IPv6 can take a long time to time-out."
   '((t :inherit fixed-pitch))
   "Face used for pre-formatted gemini text blocks.")
 
   '((t :inherit fixed-pitch))
   "Face used for pre-formatted gemini text blocks.")
 

+(defface elpher-gemini-quoted
+  '((t :inherit font-lock-doc-face))
+  "Face used for gemini quoted texts.")
+

 ;;; Model
 ;;
 
 ;;; Model
 ;;
 


@@ -265,16 +334,18 @@ some servers which do not support IPv6 can take a long time to time-out."
         (let ((url (url-generic-parse-url url-string)))
           (unless (and (not (url-fullness url)) (url-type url))
             (setf (url-fullness url) t)
         (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)
             (unless (url-type url)

-              (setf (url-type url) "gopher"))
+              (setf (url-type url) elpher-default-url-type))
+            (unless (url-host url)
+              (let ((p (split-string (url-filename url) "/" nil nil)))
+                (setf (url-host url) (car p))
+                (setf (url-filename url)
+                      (if (cdr p)
+                          (concat "/" (mapconcat #'identity (cdr p) "/"))
+                        ""))))

             (when (or (equal "gopher" (url-type url))
                       (equal "gophers" (url-type url)))
               ;; Gopher defaults
             (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 (or (equal (url-filename url) "")
                         (equal (url-filename url) "/"))
                 (setf (url-filename url) "/1")))


@@ -282,9 +353,23 @@ some servers which do not support IPv6 can take a long time to time-out."
               ;; Gemini defaults
               (if (equal (url-filename url) "")
                   (setf (url-filename url) "/"))))
               ;; Gemini defaults
               (if (equal (url-filename url) "")
                   (setf (url-filename url) "/"))))

-          url)
+          (elpher-remove-redundant-ports url))

       (set-match-data data))))
 
       (set-match-data data))))
 

+(defun elpher-remove-redundant-ports (address)
+  "Remove redundant port specifiers from ADDRESS.
+Here 'redundant' means that the specified port matches the default
+for that protocol, eg 70 for gopher."
+  (if (and (not (elpher-address-special-p address))
+           (eq (url-portspec address) ; (url-port) is too slow!
+               (pcase (url-type address)
+                 ("gemini" 1965)
+                 ((or "gopher" "gophers") 70)
+                 ("finger" 79)
+                 (_ -1))))
+      (setf (url-portspec address) nil))
+  address)
+

 (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.
 (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.


@@ -312,6 +397,11 @@ requiring gopher-over-TLS."
   "Create an ADDRESS object corresponding to the given special address symbol TYPE."
   type)
 
   "Create an ADDRESS object corresponding to the given special address symbol TYPE."
   type)
 

+(defun elpher-make-start-page ()
+  "Create the start page."
+  (elpher-make-page "Elpher Start Page"
+                    (elpher-make-special-address 'start)))
+

 (defun elpher-address-to-url (address)
   "Get string representation of ADDRESS, or nil if ADDRESS is special."
   (if (elpher-address-special-p address)
 (defun elpher-address-to-url (address)
   "Get string representation of ADDRESS, or nil if ADDRESS is special."
   (if (elpher-address-special-p address)


@@ -350,7 +440,7 @@ address refers to, via the table `elpher-type-map'."
 For gopher addresses this is a combination of the selector type and selector."
   (if (symbolp address)
       nil
 For gopher addresses this is a combination of the selector type and selector."
   (if (symbolp address)
       nil

-    (url-filename address)))
+    (url-unhex-string (url-filename address))))

 
 (defun elpher-address-host (address)
   "Retrieve host from ADDRESS object."
 
 (defun elpher-address-host (address)
   "Retrieve host from ADDRESS object."


@@ -368,13 +458,13 @@ If no address is defined, returns 0.  (This is for compatibility with the URL li
     (url-port address)))
 
 (defun elpher-address-special-p (address)
     (url-port address)))
 
 (defun elpher-address-special-p (address)

-  "Return non-nil if ADDRESS object is special (e.g. start page, bookmarks page)."
+  "Return non-nil if ADDRESS object is special (e.g. start page page)."

   (symbolp address))
 
 (defun elpher-address-gopher-p (address)
   "Return non-nill if ADDRESS object is a gopher address."
   (and (not (elpher-address-special-p address))
   (symbolp address))
 
 (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"))))
+       (member (elpher-address-protocol address) '("gopher" "gophers"))))

 
 (defun elpher-gopher-address-selector (address)
   "Retrieve gopher selector from ADDRESS object."
 
 (defun elpher-gopher-address-selector (address)
   "Retrieve gopher selector from ADDRESS object."


@@ -423,20 +513,33 @@ If no address is defined, returns 0.  (This is for compatibility with the URL li
   "Set the address corresponding to PAGE to NEW-ADDRESS."
   (setcar (cdr page) new-address))
 
   "Set the address corresponding to PAGE to NEW-ADDRESS."
   (setcar (cdr page) new-address))
 

-(defvar elpher-current-page nil)
-(defvar elpher-history nil)
+(defvar elpher-current-page nil
+  "The current page for this Elpher buffer.")
+
+(defvar elpher-history nil
+  "The local history stack for this Elpher buffer.
+This variable is used by `elpher-back' and
+`elpher-show-history'.")
+
+(defvar elpher-visited-pages nil
+  "The global history for all Elpher buffers.
+This variable is used by `elpher-show-visited-pages'.")

 
 (defun elpher-visit-page (page &optional renderer no-history)
   "Visit PAGE using its own renderer or RENDERER, if non-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."
+Additionally, push PAGE onto the history stack and the list of
+previously-visited pages,unless NO-HISTORY is non-nil."

   (elpher-save-pos)
   (elpher-process-cleanup)
   (elpher-save-pos)
   (elpher-process-cleanup)

-  (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)
+  (unless no-history
+    (unless (equal (elpher-page-address elpher-current-page)
+                   (elpher-page-address page))
+      (push elpher-current-page elpher-history)
+      (unless (or (elpher-address-special-p (elpher-page-address page))
+                  (and elpher-visited-pages
+                       (equal page (car elpher-visited-pages))))
+        (push page elpher-visited-pages))))
+  (setq-local elpher-current-page page)

   (let* ((address (elpher-page-address page))
          (type (elpher-address-type address))
          (type-record (cdr (assoc type elpher-type-map))))
   (let* ((address (elpher-page-address page))
          (type (elpher-address-type address))
          (type-record (cdr (assoc type elpher-type-map))))


@@ -460,7 +563,7 @@ unless NO-HISTORY is non-nil."
     (if previous-page
         (elpher-visit-page previous-page nil t)
       (error "No previous page"))))
     (if previous-page
         (elpher-visit-page previous-page nil t)
       (error "No previous page"))))

-      
+

 (defun elpher-reload-current-page ()
   "Reload the current page, discarding any existing cached content."
   (elpher-cache-content (elpher-page-address elpher-current-page) nil)
 (defun elpher-reload-current-page ()
   "Reload the current page, discarding any existing cached content."
   (elpher-cache-content (elpher-page-address elpher-current-page) nil)


@@ -482,6 +585,9 @@ unless NO-HISTORY is non-nil."
 ;;; Buffer preparation
 ;;
 
 ;;; Buffer preparation
 ;;
 

+(defvar elpher-buffer-name "*elpher*"
+  "The default name of the Elpher buffer.")
+

 (defun elpher-update-header ()
   "If `elpher-use-header' is true, display current page info in window header."
   (if elpher-use-header
 (defun elpher-update-header ()
   "If `elpher-use-header' is true, display current page info in window header."
   (if elpher-use-header


@@ -498,19 +604,21 @@ unless NO-HISTORY is non-nil."
 
 (defmacro elpher-with-clean-buffer (&rest args)
   "Evaluate ARGS with a clean *elpher* buffer as current."
 
 (defmacro elpher-with-clean-buffer (&rest args)
   "Evaluate ARGS with a clean *elpher* buffer as current."

-  (list 'with-current-buffer "*elpher*"
-        '(elpher-mode)
-        (append (list 'let '((inhibit-read-only t))
-                      '(setq-local network-security-level
-                                   (default-value 'network-security-level))
-                      '(erase-buffer)
-                      '(elpher-update-header))
-                args)))
+  `(with-current-buffer elpher-buffer-name
+     (unless (eq major-mode 'elpher-mode)
+       ;; avoid resetting buffer-local variables
+       (elpher-mode))
+     (let ((inhibit-read-only t))
+       (setq-local network-security-level
+                   (default-value 'network-security-level))
+       (erase-buffer)
+       (elpher-update-header)
+       ,@args)))

 
 (defun elpher-buffer-message (string &optional line)
   "Replace first line in elpher buffer with STRING.
 If LINE is non-nil, replace that line instead."
 
 (defun elpher-buffer-message (string &optional line)
   "Replace first line in elpher buffer with STRING.
 If LINE is non-nil, replace that line instead."

-  (with-current-buffer "*elpher*"
+  (with-current-buffer elpher-buffer-name

     (let ((inhibit-read-only t))
       (goto-char (point-min))
       (if line
     (let ((inhibit-read-only t))
       (goto-char (point-min))
       (if line


@@ -540,7 +648,7 @@ If LINE is non-nil, replace that line instead."
   "Preprocess text selector response contained in STRING.
 This involes decoding the character representation, and clearing
 away CRs and any terminating period."
   "Preprocess text selector response contained in STRING.
 This involes decoding the character representation, and clearing
 away CRs and any terminating period."

-  (elpher-decode (replace-regexp-in-string "\n\.\n$" "\n"
+  (elpher-decode (replace-regexp-in-string "\n\\.\n$" "\n"

                                            (replace-regexp-in-string "\r" "" string))))
 
 
                                            (replace-regexp-in-string "\r" "" string))))
 
 


@@ -592,42 +700,29 @@ unless `elpher-gemini-TLS-cert-checks' is non-nil.
 
 If non-nil, FORCE-IPV4 causes the network connection to be made over
 ipv4 only.  (The default behaviour when this is not set depends on
 
 If non-nil, FORCE-IPV4 causes the network connection to be made over
 ipv4 only.  (The default behaviour when this is not set depends on

-the host operating system and the local network capabilities."
+the host operating system and the local network capabilities.)"

   (if (and use-tls (not (gnutls-available-p)))
       (error "Use of TLS requires Emacs to be compiled with GNU TLS support")
     (unless (< (elpher-address-port address) 65536)
       (error "Cannot establish network connection: port number > 65536"))
     (when (and (eq use-tls 'gemini) (not elpher-gemini-TLS-cert-checks))
   (if (and use-tls (not (gnutls-available-p)))
       (error "Use of TLS requires Emacs to be compiled with GNU TLS support")
     (unless (< (elpher-address-port address) 65536)
       (error "Cannot establish network connection: port number > 65536"))
     (when (and (eq use-tls 'gemini) (not elpher-gemini-TLS-cert-checks))

-      (setq-local network-security-level 'low))
+      (setq-local network-security-level 'low)
+      (setq-local gnutls-verify-error nil))

     (condition-case nil
         (let* ((kill-buffer-query-functions nil)
                (port (elpher-address-port address))
     (condition-case nil
         (let* ((kill-buffer-query-functions nil)
                (port (elpher-address-port address))

+               (service (if (> port 0) port default-port))

                (host (elpher-address-host address))
                (host (elpher-address-host address))

+               (socks (or elpher-socks-always (string-suffix-p ".onion" host)))

                (response-string-parts nil)
                (bytes-received 0)
                (hkbytes-received 0)
                (response-string-parts nil)
                (bytes-received 0)
                (hkbytes-received 0)

-               (proc (make-network-process :name "elpher-process"
-                                           :host host
-                                           :family (and force-ipv4 'ipv4)
-                                           :service (if (> port 0) port default-port)
-                                           :buffer nil
-                                           :coding 'binary
-                                           :noquery t
-                                           :nowait t
-                                           :tls-parameters
-                                           (and use-tls
-                                                (cons 'gnutls-x509pki
-                                                      (gnutls-boot-parameters
-                                                       :type 'gnutls-x509pki
-                                                       :hostname host
-                                                       :keylist
-                                                       (elpher-get-current-keylist address))))))

                (timer (run-at-time elpher-connection-timeout nil
                                    (lambda ()
                                      (elpher-process-cleanup)
                                      (cond
                                         ; Try again with IPv4
                (timer (run-at-time elpher-connection-timeout nil
                                    (lambda ()
                                      (elpher-process-cleanup)
                                      (cond
                                         ; Try again with IPv4

-                                      ((not force-ipv4)
+                                      ((not (or force-ipv4 socks))

                                        (message "Connection timed out.  Retrying with IPv4.")
                                        (elpher-get-host-response address default-port
                                                                  query-string
                                        (message "Connection timed out.  Retrying with IPv4.")
                                        (elpher-get-host-response address default-port
                                                                  query-string


@@ -644,9 +739,26 @@ the host operating system and the local network capabilities."
                                                                  response-processor
                                                                  nil force-ipv4))
                                       (t
                                                                  response-processor
                                                                  nil force-ipv4))
                                       (t

-                                       (elpher-network-error address "Connection time-out.")))))))
+                                       (elpher-network-error address "Connection time-out."))))))
+               (gnutls-params (list :type 'gnutls-x509pki :hostname host
+                                    :keylist (elpher-get-current-keylist address)))
+               (proc (if socks (socks-open-network-stream "elpher-process" nil host service)
+                       (make-network-process :name "elpher-process"
+                                             :host host
+                                             :family (and force-ipv4 'ipv4)
+                                             :service service
+                                             :buffer nil
+                                             :nowait t
+                                             :tls-parameters
+                                             (and use-tls
+                                                  (cons 'gnutls-x509pki
+                                                        (apply #'gnutls-boot-parameters
+                                                               gnutls-params)))))))

           (setq elpher-network-timer timer)
           (setq elpher-network-timer timer)

-          (elpher-buffer-message (concat "Connecting to " host "..."))
+          (set-process-coding-system proc 'binary 'binary)
+          (set-process-query-on-exit-flag proc nil)
+          (elpher-buffer-message (concat "Connecting to " host "..."
+                                         " (press 'u' to abort)"))

           (set-process-filter proc
                               (lambda (_proc string)
                                 (when timer
           (set-process-filter proc
                               (lambda (_proc string)
                                 (when timer


@@ -657,10 +769,10 @@ the host operating system and the local network capabilities."
                                   (when (> new-hkbytes-received hkbytes-received)
                                     (setq hkbytes-received new-hkbytes-received)
                                     (elpher-buffer-message
                                   (when (> new-hkbytes-received hkbytes-received)
                                     (setq hkbytes-received new-hkbytes-received)
                                     (elpher-buffer-message

-                                        (concat "("
-                                                (number-to-string (/ hkbytes-received 10.0))
-                                                " MB read)")
-                                        1)))
+                                     (concat "("
+                                             (number-to-string (/ hkbytes-received 10.0))
+                                             " MB read)")
+                                     1)))

                                 (setq response-string-parts
                                       (cons string response-string-parts))))
           (set-process-sentinel proc
                                 (setq response-string-parts
                                       (cons string response-string-parts))))
           (set-process-sentinel proc


@@ -671,12 +783,13 @@ the host operating system and the local network capabilities."
                                       (cond
                                        ((string-prefix-p "open" event)    ; request URL
                                         (elpher-buffer-message
                                       (cond
                                        ((string-prefix-p "open" event)    ; request URL
                                         (elpher-buffer-message

-                                         (concat "Connected to " host ". Receiving data..."))
+                                         (concat "Connected to " host ". Receiving data..."
+                                                 " (press 'u' to abort)"))

                                         (let ((inhibit-eol-conversion t))
                                           (process-send-string proc query-string)))
                                        ((string-prefix-p "deleted" event)) ; do nothing
                                        ((and (not response-string-parts)
                                         (let ((inhibit-eol-conversion t))
                                           (process-send-string proc query-string)))
                                        ((string-prefix-p "deleted" event)) ; do nothing
                                        ((and (not response-string-parts)

-                                             (not (or elpher-ipv4-always force-ipv4)))
+                                             (not (or elpher-ipv4-always force-ipv4 socks)))

                                         ; Try again with IPv4
                                         (message "Connection failed. Retrying with IPv4.")
                                         (elpher-get-host-response address default-port
                                         ; Try again with IPv4
                                         (message "Connection failed. Retrying with IPv4.")
                                         (elpher-get-host-response address default-port


@@ -692,58 +805,138 @@ the host operating system and the local network capabilities."
                                        (t
                                         (error "No response from server")))
                                     (error
                                        (t
                                         (error "No response from server")))
                                     (error

-                                     (elpher-network-error address the-error))))))
+                                     (elpher-network-error address the-error)))))
+          (when socks
+            (if use-tls (apply #'gnutls-negotiate :process proc gnutls-params))
+            (funcall (process-sentinel proc) proc "open\n")))

       (error
        (error "Error initiating connection to server")))))
 
       (error
        (error "Error initiating connection to server")))))
 

-(defun elpher-generate-certificate (name key-file cert-file &optional temporary)
+
+;;; Client-side TLS Certificate Management
+;;
+
+(defun elpher-generate-certificate (common-name key-file cert-file &optional temporary)
+  "Generate a key and a self-signed client TLS certificate using openssl.
+
+The Common Name field of the certificate is set to COMMON-NAME.  The
+arguments KEY-FILE and CERT-FILE should contain the absolute paths of
+the key and certificate files to write.
+
+If TEMPORARY is non-nil, the certificate will be given an exporation
+period of one day, and the key and certificate files will be deleted
+when the certificate is no longer needed for the current session.
+
+Otherwise, the certificate will be given a 100 year expiration period
+and the files will not be deleted.
+
+The function returns a list containing the current host name, the
+temporary flag, and the key and cert file names in the form required
+by `gnutls-boot-parameters`."

   (let ((exp-key-file (expand-file-name key-file))
         (exp-cert-file (expand-file-name cert-file)))
   (let ((exp-key-file (expand-file-name key-file))
         (exp-cert-file (expand-file-name cert-file)))

-    (call-process "openssl" nil nil nil
-                  "req" "-x509" "-newkey" "rsa:2048"
-                  "-days" (if temporary "1" "36500")
-                  "-nodes"
-                  "-subj" (concat "/CN=" name)
-                  "-keyout" exp-key-file
-                  "-out" exp-cert-file)
-    (list (elpher-address-host (elpher-page-address elpher-current-page))
-          temporary exp-key-file exp-cert-file)))
+    (condition-case nil
+        (progn
+          (call-process elpher-openssl-command nil nil nil
+                        "req" "-x509" "-newkey" "rsa:2048"
+                        "-days" (if temporary "1" "36500")
+                        "-nodes"
+                        "-subj" (concat "/CN=" common-name)
+                        "-keyout" exp-key-file
+                        "-out" exp-cert-file)
+          (list (elpher-address-host (elpher-page-address elpher-current-page))
+                temporary exp-key-file exp-cert-file))
+      (error
+       (message "Check that openssl is installed, or customize `elpher-openssl-command`.")
+       (error "Program 'openssl', required for certificate generation, not found")))))

 
 (defun elpher-generate-throwaway-certificate ()
 
 (defun elpher-generate-throwaway-certificate ()

+  "Generate and return details of a throwaway certificate.
+The key and certificate files will be deleted when they are no
+longer needed for this session."

   (let* ((file-base (make-temp-name "elpher"))
          (key-file (concat temporary-file-directory file-base ".key"))
          (cert-file (concat temporary-file-directory file-base ".crt")))
     (elpher-generate-certificate file-base key-file cert-file t)))
 
   (let* ((file-base (make-temp-name "elpher"))
          (key-file (concat temporary-file-directory file-base ".key"))
          (cert-file (concat temporary-file-directory file-base ".crt")))
     (elpher-generate-certificate file-base key-file cert-file t)))
 

-(defun elpher-generate-permanent-certificate (file-base)
+(defun elpher-generate-persistent-certificate (file-base common-name)
+  "Generate and return details of a persistent certificate.
+The argument FILE-BASE is used as the base for the key and certificate
+files, while COMMON-NAME specifies the common name field of the
+certificate.
+
+The key and certificate files are written to in `elpher-certificate-directory'."

   (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
          (cert-file (concat elpher-certificate-directory file-base ".crt")))
   (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
          (cert-file (concat elpher-certificate-directory file-base ".crt")))

-    (elpher-generate-certificate file-base key-file cert-file)))
+    (elpher-generate-certificate common-name key-file cert-file)))

 
 (defun elpher-get-existing-certificate (file-base)
 
 (defun elpher-get-existing-certificate (file-base)

+  "Return a certificate object corresponding to an existing certificate.
+It is assumed that the key files FILE-BASE.key and FILE-BASE.crt exist in
+the directory `elpher-certificate-directory'."
+  (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
+         (cert-file (concat elpher-certificate-directory file-base ".crt")))
+    (list (elpher-address-host (elpher-page-address elpher-current-page))
+          nil
+          (expand-file-name key-file)
+          (expand-file-name cert-file))))
+
+(defun elpher-install-and-use-existing-certificate (key-file-src cert-file-src file-base)
+  "Install a key+certificate file pair in `elpher-certificate-directory'.
+The strings KEY-FILE-SRC and CERT-FILE-SRC are the existing key and
+certificate files to install.  The argument FILE-BASE is used as the
+base for the installed key and certificate files."

   (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
          (cert-file (concat elpher-certificate-directory file-base ".crt")))
   (let* ((key-file (concat elpher-certificate-directory file-base ".key"))
          (cert-file (concat elpher-certificate-directory file-base ".crt")))

+    (if (or (file-exists-p key-file)
+            (file-exists-p cert-file))
+        (error "A certificate with base name %s is already installed" file-base))
+    (copy-file key-file-src key-file)
+    (copy-file cert-file-src cert-file)

     (list (elpher-address-host (elpher-page-address elpher-current-page))
           nil
           (expand-file-name key-file)
           (expand-file-name cert-file))))
 
 (defun elpher-list-existing-certificates ()
     (list (elpher-address-host (elpher-page-address elpher-current-page))
           nil
           (expand-file-name key-file)
           (expand-file-name cert-file))))
 
 (defun elpher-list-existing-certificates ()

+  "Return a list of the persistent certificates in `elpher-certificate-directory'."
+  (unless (file-directory-p elpher-certificate-directory)
+    (make-directory elpher-certificate-directory))

   (mapcar
    (lambda (file)
      (file-name-sans-extension file))
   (mapcar
    (lambda (file)
      (file-name-sans-extension file))

-   (directory-files elpher-certificate-directory nil "\.key$")))
-    
+   (directory-files elpher-certificate-directory nil "\\.key$")))
+
+(defun elpher-forget-current-certificate ()
+  "Causes any current certificate to be forgotten.)
+In the case of throwaway certificates, the key and certificate files
+are also deleted."
+  (interactive)
+  (when elpher-client-certificate
+    (unless (and (called-interactively-p 'any)
+                 (not (y-or-n-p (concat "Really forget client certificate? "
+                                        "(Throwaway certificates will be deleted.)"))))
+      (when (cadr elpher-client-certificate)
+        (delete-file (elt elpher-client-certificate 2))
+        (delete-file (elt elpher-client-certificate 3)))
+      (setq elpher-client-certificate nil)
+      (if (called-interactively-p 'any)
+          (message "Client certificate forgotten.")))))

 
 (defun elpher-get-current-keylist (address)
 
 (defun elpher-get-current-keylist (address)

+  "Retrieve the `gnutls-boot-parameters'-compatable keylist.
+
+This is obtained from the client certificate described by
+`elpher-current-certificate', if one is available and the host for
+that certificate matches the host in ADDRESS.
+
+If `elpher-current-certificate' is non-nil, and its host name doesn't
+match that of ADDRESS, the certificate is forgotten."

   (if elpher-client-certificate
       (if (string= (car elpher-client-certificate)
                    (elpher-address-host address))
           (list (cddr elpher-client-certificate))
   (if elpher-client-certificate
       (if (string= (car elpher-client-certificate)
                    (elpher-address-host address))
           (list (cddr elpher-client-certificate))

-        (when (cadr elpher-client-certificate)
-          (delete-file (elt elpher-client-certificate 2))
-          (delete-file (elt elpher-client-certificate 3)))
-        (setq elpher-client-certificate nil)
+        (elpher-forget-current-certificate)

         (message "Disabling client certificate for new host")
         nil)
     nil))
         (message "Disabling client certificate for new host")
         nil)
     nil))


@@ -834,7 +1027,7 @@ If ADDRESS is not supplied or nil the record is rendered as an
     (if type-map-entry
         (let* ((margin-code (elt type-map-entry 2))
                (face (elt type-map-entry 3))
     (if type-map-entry
         (let* ((margin-code (elt type-map-entry 2))
                (face (elt type-map-entry 3))

-               (filtered-display-string (ansi-color-filter-apply display-string))
+               (filtered-display-string (elpher-color-filter-apply display-string))

                (page (elpher-make-page filtered-display-string address)))
           (elpher-insert-margin margin-code)
           (insert-text-button filtered-display-string
                (page (elpher-make-page filtered-display-string address)))
           (elpher-insert-margin margin-code)
           (insert-text-button filtered-display-string


@@ -872,7 +1065,7 @@ If ADDRESS is not supplied or nil the record is rendered as an
 ;; Text rendering
 
 (defconst elpher-url-regex
 ;; Text rendering
 
 (defconst elpher-url-regex

-  "\\([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\-_~?/@|#]\\)?\\)?"
+  "\\([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-buttonify-urls (string)
   "Regexp used to locate and buttinofy URLs in text files loaded by elpher.")
 
 (defun elpher-buttonify-urls (string)


@@ -883,24 +1076,24 @@ If ADDRESS is not supplied or nil the record is rendered as an
     (while (re-search-forward elpher-url-regex nil t)
       (let ((page (elpher-make-page (substring-no-properties (match-string 0))
                                     (elpher-address-from-url (match-string 0)))))
     (while (re-search-forward elpher-url-regex nil t)
       (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-page  page
-                            'action #'elpher-click-link
-                            'follow-link t
-                            'help-echo #'elpher--page-button-help
-                            'face 'button)))
+        (make-text-button (match-beginning 0)
+                          (match-end 0)
+                          'elpher-page  page
+                          'action #'elpher-click-link
+                          'follow-link t
+                          'help-echo #'elpher--page-button-help
+                          'face 'button)))

     (buffer-string)))
 
 (defconst elpher-ansi-regex "\x1b\\[[^m]*m"
     (buffer-string)))
 
 (defconst elpher-ansi-regex "\x1b\\[[^m]*m"

-  "Wildly incomplete regexp used to strip out some troublesome ANSI escape sequences.")
+  "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
 
 (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))))
+                             (elpher-color-filter-apply string)
+                           (elpher-color-apply string))))

 
 (defun elpher-render-text (data &optional _mime-type-string)
   "Render DATA as text.  MIME-TYPE-STRING is unused."
 
 (defun elpher-render-text (data &optional _mime-type-string)
   "Render DATA as text.  MIME-TYPE-STRING is unused."


@@ -933,9 +1126,9 @@ Currently includes buttonifying URLs and processing ANSI escape codes."
 (defun elpher-get-gopher-query-page (renderer)
   "Getter for gopher addresses requiring input.
 The response is rendered using the rendering function RENDERER."
 (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))
+  (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)
     (if (and content (funcall renderer nil))
         (elpher-with-clean-buffer
          (insert content)


@@ -956,7 +1149,7 @@ The response is rendered using the rendering function RENDERER."
             (elpher-get-gopher-response search-address renderer))
         (if aborted
             (elpher-visit-previous-page))))))
             (elpher-get-gopher-response search-address renderer))
         (if aborted
             (elpher-visit-previous-page))))))

- 
+

 ;; Raw server response rendering
 
 (defun elpher-render-raw (data &optional mime-type-string)
 ;; Raw server response rendering
 
 (defun elpher-render-raw (data &optional mime-type-string)


@@ -1041,7 +1234,10 @@ that the response was malformed."
         (?1 ; Input required
          (elpher-with-clean-buffer
           (insert "Gemini server is requesting input."))
         (?1 ; Input required
          (elpher-with-clean-buffer
           (insert "Gemini server is requesting input."))

-         (let* ((query-string (read-string (concat response-meta ": ")))
+         (let* ((query-string
+                 (if (eq (elt response-code 1) ?1)
+                     (read-passwd (concat response-meta ": "))
+                   (read-string (concat response-meta ": "))))

                 (query-address (seq-copy (elpher-page-address elpher-current-page)))
                 (old-fname (url-filename query-address)))
            (setf (url-filename query-address)
                 (query-address (seq-copy (elpher-page-address elpher-current-page)))
                 (old-fname (url-filename query-address)))
            (setf (url-filename query-address)


@@ -1076,36 +1272,72 @@ that the response was malformed."
             (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
           (auto-fill-mode 1)
           (elpher-gemini-insert-text response-meta))
             (insert "Gemini server is requesting a valid TLS certificate:\n\n"))
           (auto-fill-mode 1)
           (elpher-gemini-insert-text response-meta))

-         (let* ((read-answer-short t)
-                (res (read-answer "What do you want to do? "
-                                  '(("throwaway" ?t "generate and use throw-away certificate")
-                                    ("permanent" ?p "generate and use permanent certificate")
-                                    ("existing" ?e "use existing certificate")
-                                    ("abort" ?a "stop immediately")))))
-           (pcase res
-             ("throwaway"
-              (setq elpher-client-certificate (elpher-generate-throwaway-certificate)))
-             ("permanent"
-              (let ((file-base (read-string "Name for certificate: ")))
-                (setq elpher-client-certificate
-                      (elpher-generate-permanent-certificate file-base))))
-             ("existing"
-              (let ((file-base (completing-read "Name of existing certificate (autocompletes, empty response aborts): "
-                                                (elpher-list-existing-certificates)
-                                                nil t)))
-                (if (string-empty-p file-base)
-                    (error "Gemini server requires a client certificate and none was provided")
-                  (setq elpher-client-certificate
-                        (elpher-get-existing-certificate file-base)))))
-              ;; TODO
-             ("abort"
-              (error "Gemini server requires a client certificate and none was provided")))
-           (elpher-with-clean-buffer)
-           (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer)))
+         (let ((chosen-certificate (elpher-choose-client-certificate)))
+           (unless chosen-certificate
+             (error "Gemini server requires a client certificate and none was provided"))
+           (setq elpher-client-certificate chosen-certificate))
+         (elpher-with-clean-buffer)
+         (elpher-get-gemini-response (elpher-page-address elpher-current-page) renderer))

         (_other
          (error "Gemini server response unknown: %s %s"
                 response-code response-meta))))))
 
         (_other
          (error "Gemini server response unknown: %s %s"
                 response-code response-meta))))))
 

+(defun elpher--read-answer-polyfill (question answers)
+  "Polyfill for `read-answer' in Emacs 26.1.
+QUESTION is a string containing a question, and ANSWERS
+is a list of possible answers."
+    (completing-read question (mapcar 'identity answers)))
+
+(if (fboundp 'read-answer)
+    (defalias 'elpher-read-answer 'read-answer)
+  (defalias 'elpher-read-answer 'elpher--read-answer-polyfill))
+
+(defun elpher-choose-client-certificate ()
+  "Prompt for a client certificate to use to establish a TLS connection."
+  (let* ((read-answer-short t))
+    (pcase (read-answer "What do you want to do? "
+                        '(("throwaway" ?t
+                           "generate and use throw-away certificate")
+                          ("persistent" ?p
+                           "generate new or use existing persistent certificate")
+                          ("abort" ?a
+                           "stop immediately")))
+      ("throwaway"
+       (setq elpher-client-certificate (elpher-generate-throwaway-certificate)))
+      ("persistent"
+       (let* ((existing-certificates (elpher-list-existing-certificates))
+              (file-base (completing-read
+                          "Nickname for new or existing certificate (autocompletes, empty response aborts): "
+                          existing-certificates)))
+         (if (string-empty-p (string-trim file-base))
+             nil
+           (if (member file-base existing-certificates)
+               (setq elpher-client-certificate
+                     (elpher-get-existing-certificate file-base))
+             (pcase (read-answer "Generate new certificate or install externally-generated one? "
+                                 '(("new" ?n
+                                    "generate new certificate")
+                                   ("install" ?i
+                                    "install existing certificate")
+                                   ("abort" ?a
+                                    "stop immediately")))
+               ("new"
+                (let ((common-name (read-string "Common Name field for new certificate: "
+                                                file-base)))
+                  (message "New key and self-signed certificate written to %s"
+                           elpher-certificate-directory)
+                  (elpher-generate-persistent-certificate file-base common-name)))
+               ("install"
+                (let* ((cert-file (read-file-name "Certificate file: " nil nil t))
+                       (key-file (read-file-name "Key file: " nil nil t)))
+                  (message "Key and certificate installed in %s for future use"
+                           elpher-certificate-directory)
+                  (elpher-install-and-use-existing-certificate key-file
+                                                               cert-file
+                                                               file-base)))
+               ("abort" nil))))))
+      ("abort" nil))))
+

 (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))
 (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))


@@ -1113,8 +1345,8 @@ that the response was malformed."
     (condition-case the-error
         (if (and content (funcall renderer nil))
             (elpher-with-clean-buffer
     (condition-case the-error
         (if (and content (funcall renderer nil))
             (elpher-with-clean-buffer

-              (insert content)
-              (elpher-restore-pos))
+             (insert content)
+             (elpher-restore-pos))

           (elpher-with-clean-buffer
            (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
           (setq elpher-gemini-redirect-chain nil)
           (elpher-with-clean-buffer
            (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
           (setq elpher-gemini-redirect-chain nil)


@@ -1122,7 +1354,6 @@ that the response was malformed."
       (error
        (elpher-network-error address the-error)))))
 
       (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)
 (defun elpher-render-gemini (body &optional mime-type-string)
   "Render gemini response BODY with rendering MIME-TYPE-STRING."
   (if (not body)


@@ -1189,7 +1420,10 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
     (string-join (reverse path-reversed-normalized) "/")))
 
 (defun elpher-address-from-gemini-url (url)
     (string-join (reverse path-reversed-normalized) "/")))
 
 (defun elpher-address-from-gemini-url (url)

-  "Extract address from URL with defaults as per gemini map files."
+  "Extract address from URL with defaults as per gemini map files.
+While there's obviously some redundancy here between this function and
+`elpher-address-from-url', gemini map file URLs require enough special
+treatment that a separate function is warranted."

   (let ((address (url-generic-parse-url url))
         (current-address (elpher-page-address elpher-current-page)))
     (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
   (let ((address (url-generic-parse-url url))
         (current-address (elpher-page-address elpher-current-page)))
     (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls


@@ -1205,10 +1439,10 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
                         (url-filename address)))))
       (unless (url-type address)
         (setf (url-type address) "gemini"))
                         (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))
+      (when (equal (url-type address) "gemini")
+        (setf (url-filename address)
+              (elpher-collapse-dot-sequences (url-filename address)))))
+    (elpher-remove-redundant-ports address)))

 
 (defun elpher-gemini-insert-link (link-line)
   "Insert link described by LINK-LINE into a text/gemini document."
 
 (defun elpher-gemini-insert-link (link-line)
   "Insert link described by LINK-LINE into a text/gemini document."


@@ -1221,7 +1455,7 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
       (insert elpher-gemini-link-string)
       (if type-map-entry
           (let* ((face (elt type-map-entry 3))
       (insert elpher-gemini-link-string)
       (if type-map-entry
           (let* ((face (elt type-map-entry 3))

-                 (filtered-display-string (ansi-color-filter-apply display-string))
+                 (filtered-display-string (elpher-color-filter-apply display-string))

                  (page (elpher-make-page filtered-display-string address)))
             (insert-text-button filtered-display-string
                                 'face face
                  (page (elpher-make-page filtered-display-string address)))
             (insert-text-button filtered-display-string
                                 'face face


@@ -1231,37 +1465,51 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
                                 'help-echo #'elpher--page-button-help))
         (insert (propertize display-string 'face 'elpher-unknown)))
       (insert "\n"))))
                                 'help-echo #'elpher--page-button-help))
         (insert (propertize display-string 'face 'elpher-unknown)))
       (insert "\n"))))

-  
+

 (defun elpher-gemini-insert-header (header-line)
   "Insert header described by HEADER-LINE into a text/gemini document.
 The gemini map file line describing the header is given
 by HEADER-LINE."
   (when (string-match "^\\(#+\\)[ \t]*" header-line)
 (defun elpher-gemini-insert-header (header-line)
   "Insert header described by HEADER-LINE into a text/gemini document.
 The gemini map file line describing the header is given
 by HEADER-LINE."
   (when (string-match "^\\(#+\\)[ \t]*" header-line)

-    (let ((level (length (match-string 1 header-line)))
-          (header (substring header-line (match-end 0))))
+    (let* ((level (length (match-string 1 header-line)))
+           (header (substring header-line (match-end 0)))
+           (face (pcase level
+                   (1 'elpher-gemini-heading1)
+                   (2 'elpher-gemini-heading2)
+                   (3 'elpher-gemini-heading3)
+                   (_ 'default)))
+           (fill-column (if (display-graphic-p)
+                            (/ (* fill-column
+                                  (font-get (font-spec :name (face-font 'default)) :size))
+                               (font-get (font-spec :name (face-font face)) :size)) fill-column)))
+      (setq elpher--gemini-page-headings (cons (cons header (point))
+                                               elpher--gemini-page-headings))

       (unless (display-graphic-p)
         (insert (make-string level ?#) " "))
       (unless (display-graphic-p)
         (insert (make-string level ?#) " "))

-      (insert (propertize header 'face
-                          (pcase level
-                            (1 'elpher-gemini-heading1)
-                            (2 'elpher-gemini-heading2)
-                            (3 'elpher-gemini-heading3)
-                            (_ 'default)))
-              "\n"))))
+      (insert (propertize header 'face face))
+      (newline))))

 
 (defun elpher-gemini-insert-text (text-line)
   "Insert a plain non-preformatted TEXT-LINE into a text/gemini document.
 This function uses Emacs' auto-fill to wrap text sensibly to a maximum
 
 (defun elpher-gemini-insert-text (text-line)
   "Insert a plain non-preformatted TEXT-LINE into a text/gemini document.
 This function uses Emacs' auto-fill to wrap text sensibly to a maximum

-width defined by elpher-gemini-max-fill-width."
-  (string-match "\\(^[ \t]*\\)\\(\*[ \t]+\\|>[ \t]*\\)?" text-line)
-  (let* ((processed-text-line (if (match-string 2 text-line)
-                                  (concat
-                                   (replace-regexp-in-string "\*"
-                                                             elpher-gemini-bullet-string
-                                                             (match-string 0 text-line))
-                                   (substring text-line (match-end 0)))
-                                text-line))
-         (adaptive-fill-mode nil)
+width defined by `elpher-gemini-max-fill-width'."
+  (string-match "\\(^[ \t]*\\)\\(\\*[ \t]+\\|>[ \t]*\\)?" text-line)
+  (let* ((line-prefix (match-string 2 text-line))
+         (processed-text-line
+          (if line-prefix
+              (cond ((string-prefix-p "*" line-prefix)
+                     (concat
+                      (replace-regexp-in-string "\\*"
+                                                elpher-gemini-bullet-string
+                                                (match-string 0 text-line))
+                      (substring text-line (match-end 0))))
+                    ((string-prefix-p ">" line-prefix)
+                     (propertize text-line 'face 'elpher-gemini-quoted))
+                    (t text-line))
+            text-line))
+         (adaptive-fill-mode t)
+        ;; fill-prefix is important for adaptive-fill-mode: without
+        ;; it, multi-line list items are not indented correct

          (fill-prefix (if (match-string 2 text-line)
                           (replace-regexp-in-string "[>\*]" " " (match-string 0 text-line))
                         nil)))
          (fill-prefix (if (match-string 2 text-line)
                           (replace-regexp-in-string "[>\*]" " " (match-string 0 text-line))
                         nil)))


@@ -1271,6 +1519,7 @@ width defined by elpher-gemini-max-fill-width."
 (defun elpher-render-gemini-map (data _parameters)
   "Render DATA as a gemini map file, PARAMETERS is currently unused."
   (elpher-with-clean-buffer
 (defun elpher-render-gemini-map (data _parameters)
   "Render DATA as a gemini map file, PARAMETERS is currently unused."
   (elpher-with-clean-buffer

+   (setq elpher--gemini-page-headings nil)

    (let ((preformatted nil))
      (auto-fill-mode 1)
      (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))
    (let ((preformatted nil))
      (auto-fill-mode 1)
      (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))


@@ -1280,9 +1529,11 @@ width defined by elpher-gemini-max-fill-width."
         (preformatted (insert (elpher-process-text-for-display
                                (propertize line 'face 'elpher-gemini-preformatted))
                               "\n"))
         (preformatted (insert (elpher-process-text-for-display
                                (propertize line 'face 'elpher-gemini-preformatted))
                               "\n"))

-        ((string-prefix-p "=>" line) (elpher-gemini-insert-link line))
+        ((string-prefix-p "=>" line)
+         (elpher-gemini-insert-link line))

         ((string-prefix-p "#" line) (elpher-gemini-insert-header line))
         (t (elpher-gemini-insert-text line)))))
         ((string-prefix-p "#" line) (elpher-gemini-insert-header line))
         (t (elpher-gemini-insert-text line)))))

+   (setq elpher--gemini-page-headings (nreverse elpher--gemini-page-headings))

    (elpher-cache-content
     (elpher-page-address elpher-current-page)
     (buffer-string))))
    (elpher-cache-content
     (elpher-page-address elpher-current-page)
     (buffer-string))))


@@ -1295,6 +1546,7 @@ width defined by elpher-gemini-max-fill-width."
     (elpher-page-address elpher-current-page)
     (buffer-string))))
 
     (elpher-page-address elpher-current-page)
     (buffer-string))))
 

+

 ;; Finger page connection
 
 (defun elpher-get-finger-page (renderer)
 ;; Finger page connection
 
 (defun elpher-get-finger-page (renderer)


@@ -1321,6 +1573,22 @@ The result is rendered using RENDERER."
          (elpher-network-error address the-error))))))
 
 
          (elpher-network-error address the-error))))))
 
 

+;; 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-previous-page)
+    (if (> port 0)
+        (telnet host port)
+      (telnet host))))
+
+

 ;; Other URL page opening
 
 (defun elpher-get-other-url-page (renderer)
 ;; Other URL page opening
 
 (defun elpher-get-other-url-page (renderer)


@@ -1337,22 +1605,8 @@ The result is rendered using RENDERER."
           (browse-web url)
         (browse-url url)))))
 
           (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-previous-page)
-    (if (> port 0)
-        (telnet host port)
-      (telnet host))))

 
 

-;; Start page page retrieval
+;; Start page retrieval

 
 (defun elpher-get-start-page (renderer)
   "Getter which displays the start page (RENDERER must be nil)."
 
 (defun elpher-get-start-page (renderer)
   "Getter which displays the start page (RENDERER must be nil)."


@@ -1371,18 +1625,19 @@ The result is rendered using RENDERER."
            " - RET/mouse-1: open item under cursor\n"
            " - m: select an item on current page by name (autocompletes)\n"
            " - u/mouse-3/U: return to previous page or to the start page\n"
            " - RET/mouse-1: open item under cursor\n"
            " - m: select an item on current page by name (autocompletes)\n"
            " - u/mouse-3/U: return to previous page or to the start page\n"

-           " - o/O: visit different selector or the root menu of the current server\n"

            " - g: go to a particular address (gopher, gemini, finger)\n"
            " - g: go to a particular address (gopher, gemini, finger)\n"

+           " - o/O: open a different address selector or the root menu of the current server\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"
            " - 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"

-           " - x/X: remove bookmark for item under cursor or current page\n"
-           " - B: visit the bookmarks page\n"
+           " - B: list all bookmarks\n"
+           " - s/S: show current history stack or all previously visted pages\n"

            " - r: redraw current page (using cached contents if available)\n"
            " - R: reload current page (regenerates cache)\n"
            " - r: redraw current page (using cached contents if available)\n"
            " - R: reload current page (regenerates cache)\n"

-           " - S: set character coding system for gopher (default is to autodetect)\n"
+           " - !: set character coding system for gopher (default is to autodetect)\n"

            " - T: toggle TLS gopher mode\n"
            " - T: toggle TLS gopher mode\n"

+           " - F: forget/discard current TLS client certificate\n"

            " - .: display the raw server response for the current page\n"
            "\n"
            "Start your exploration of gopher space and gemini:\n")
            " - .: display the raw server response for the current page\n"
            "\n"
            "Start your exploration of gopher space and gemini:\n")


@@ -1394,11 +1649,22 @@ The result is rendered using RENDERER."
            "Alternatively, select a search engine and enter some search terms:\n")
    (elpher-insert-index-record "Gopher Search Engine (Veronica-2)"
                                (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
            "Alternatively, select a search engine and enter some search terms:\n")
    (elpher-insert-index-record "Gopher Search Engine (Veronica-2)"
                                (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))

-   (elpher-insert-index-record "Gemini Search Engine (GUS)"
-                               (elpher-address-from-url "gemini://gus.guru/search"))
+   (elpher-insert-index-record "Gemini Search Engine (geminispace.info)"
+                               (elpher-address-from-url "gemini://geminispace.info/search"))

    (insert "\n"
    (insert "\n"

-           "This page contains your bookmarked sites (also visit with B):\n")
-   (elpher-insert-index-record "Your Bookmarks" 'bookmarks)
+           "Your bookmarks are stored in your ")
+   (let ((help-string "RET,mouse-1: Open Emacs bookmark list"))
+     (insert-text-button "Emacs bookmark list"
+                         'face 'link
+                         'action (lambda (_)
+                                   (interactive)
+                                   (call-interactively #'bookmark-bmenu-list))
+                         'follow-link t
+                         'help-echo help-string))
+   (insert ".\n")
+   (insert (propertize
+            "(Bookmarks from legacy elpher-bookmarks files will be automatically imported.)\n"
+            'face 'shadow))

    (insert "\n"
            "For Elpher release news or to leave feedback, visit:\n")
    (elpher-insert-index-record "The Elpher Project Page"
    (insert "\n"
            "For Elpher release news or to leave feedback, visit:\n")
    (elpher-insert-index-record "The Elpher Project Page"


@@ -1423,110 +1689,240 @@ The result is rendered using RENDERER."
             'face 'shadow))
    (elpher-restore-pos)))
 
             'face 'shadow))
    (elpher-restore-pos)))
 

-;; Bookmarks page page retrieval
+;; History page retrieval
+
+(defun elpher-show-history ()
+  "Show the current contents of elpher's history stack.
+Use \\[elpher-show-visited-pages] to see the entire history.
+This is rendered using `elpher-get-history-page' via `elpher-type-map'."
+  (interactive)
+  (elpher-visit-page
+   (elpher-make-page "Current History Stack"
+                    (elpher-make-special-address 'history))))
+
+(defun elpher-show-visited-pages ()
+  "Show the all the pages you've visited using Elpher.
+Use \\[elpher-show-history] to see just the current history stack.
+This is rendered using `elpher-get-visited-pages-page' via `elpher-type-map'."
+  (interactive)
+  (elpher-visit-page
+   (elpher-make-page "Elpher Visted Pages"
+                    (elpher-make-special-address 'visited-pages))))

 
 

-(defun elpher-get-bookmarks-page (renderer)
-  "Getter to load and display the current bookmark list (RENDERER must be nil)."
+(defun elpher-get-history-page (renderer)
+  "Getter which displays the history page (RENDERER must be nil)."

   (when renderer
     (elpher-visit-previous-page)
   (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-address-from-url (elpher-bookmark-url bookmark))))
-             (elpher-insert-index-record display-string address)))
-       (insert "No bookmarks found.\n")))
-   (insert "\n-----------------------\n"
-           "\n"
-           "- u: return to previous page\n"
-           "- x: delete selected bookmark\n"
-           "- a: rename selected bookmark\n"
-           "\n"
-           "Bookmarks are stored in the file ")
-   (let ((filename elpher-bookmarks-file)
-         (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)))
-  
+    (error "Command not supported for history page"))
+  (elpher-display-history-links elpher-history "Current history stack"))
+
+(defun elpher-get-visited-pages-page (renderer)
+  "Getter which displays the list of visited pages (RENDERER must be nil)."
+  (when renderer
+    (elpher-visit-previous-page)
+    (error "Command not supported for history page"))
+  (elpher-display-history-links
+   (seq-filter (lambda (page)
+                 (not (elpher-address-special-p (elpher-page-address page))))
+               elpher-visited-pages)
+   "All visited pages"))
+
+(defun elpher-display-history-links (pages title)
+  "Show all PAGES in an Elpher buffer with a given TITLE."
+  (let* ((title-line (concat "---- " title " ----"))
+         (footer-line (make-string (length title-line) ?-)))
+    (elpher-with-clean-buffer
+     (insert title-line "\n\n")
+     (if pages
+         (dolist (page pages)
+          (when page
+             (let ((display-string (elpher-page-display-string page))
+                  (address (elpher-page-address page)))
+               (elpher-insert-index-record display-string address))))
+       (insert "No history items found.\n"))
+     (insert "\n" footer-line "\n"
+             "Select and entry or press 'u' to return to the previous page.")
+     (elpher-restore-pos))))
+

 
 ;;; Bookmarks
 
 ;;; Bookmarks

+
+;; This code allows Elpher to use the standard Emacs bookmarks: `C-x r
+;; m' to add a bookmark, `C-x r l' to list bookmarks (which is where
+;; you can anotate bookmarks!), `C-x r b' to jump to a bookmark, and
+;; so on. See the Bookmarks section in the Emacs info manual for more.
+
+(defvar elpher-bookmark-link nil
+  "Prefer bookmarking a link or the current page.
+Bind this variable dynamically, or set it to t.
+If you set it to t, the commands \\[bookmark-set-no-overwrite]
+and \\[elpher-set-bookmark-no-overwrite] do the same thing.")
+
+(defun elpher-bookmark-make-record ()
+  "Return a bookmark record.
+If `elpher-bookmark-link' is non-nil and point is on a link button,
+return a bookmark record for that link.  Otherwise, return a bookmark
+record for the current elpher page."
+  (let* ((button (and elpher-bookmark-link (button-at (point))))
+        (page (if button
+                  (button-get button 'elpher-page)
+                elpher-current-page))
+        (address (elpher-page-address page))
+        (url (elpher-address-to-url address))
+        (display-string (elpher-page-display-string page))
+        (pos (if button nil (point))))
+    (if (elpher-address-special-p address)
+       (error "Cannot bookmark %s" display-string)
+      `(,display-string
+       (defaults . (,display-string))
+       (position . ,pos)
+       (location . ,url)
+       (handler . elpher-bookmark-jump)))))
+
+;;;###autoload
+(defun elpher-bookmark-jump (bookmark)
+  "Go to a particular BOOKMARK."
+  (let* ((url (cdr (assq 'location bookmark))))
+    (elpher-go url)))
+
+(defun elpher-set-bookmark-no-overwrite ()
+  "Bookmark the link at point.
+To bookmark the current page, use \\[bookmark-set-no-overwrite]."
+  (interactive)
+  (let ((elpher-bookmark-link t))
+    (bookmark-set-no-overwrite)))
+
+(defun elpher-bookmark-import (file)
+  "Import Elpher bookmarks file FILE into Emacs bookmarks."
+  (interactive (list (if (and (boundp 'elpher-bookmarks-file)
+                             (file-readable-p elpher-bookmarks-file))
+                        elpher-bookmarks-file
+                      (read-file-name "Old Elpher bookmarks: "
+                                      user-emacs-directory nil t
+                                      "elpher-bookmarks"))))
+  (require 'bookmark)
+  (dolist (bookmark (with-temp-buffer
+                     (insert-file-contents file)
+                     (read (current-buffer))))
+    (let* ((display-string (car bookmark))
+           (url (cadr bookmark))
+          (record `(,display-string
+                    (location . ,url)
+                    (handler . elpher-bookmark-jump))))
+      (bookmark-store display-string (cdr record) t)))
+  (bookmark-save))
+
+;;; Integrations

 ;;
 
 ;;
 

-(defun elpher-make-bookmark (display-string url)
-  "Make an elpher bookmark.
-DISPLAY-STRING determines how the bookmark will appear in the
-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."
-  (elt bookmark 0))
-
-(defun elpher-set-bookmark-display-string (bookmark display-string)
-  "Set the display string of BOOKMARK to DISPLAY-STRING."
-  (setcar bookmark display-string))
-
-(defun elpher-bookmark-url (bookmark)
-  "Get the address for BOOKMARK."
-  (elt bookmark 1))
-
-(defun elpher-save-bookmarks (bookmarks)
-  "Record the bookmark list BOOKMARKS to the user's bookmark file.
-Beware that this completely replaces the existing contents of the file."
-  (with-temp-file elpher-bookmarks-file
-    (erase-buffer)
-    (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."
-  (let ((bookmarks
-         (with-temp-buffer
-           (ignore-errors
-             (insert-file-contents elpher-bookmarks-file)
-             (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.)))
-If ADDRESS is already bookmarked, update the label only."
-  (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)
-        (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-url bookmark) url)))
-                 (elpher-load-bookmarks)))))
+;;; Org
+
+(defun elpher-org-export-link (link description format protocol)
+  "Export a LINK with DESCRIPTION for the given PROTOCOL and FORMAT.
+
+FORMAT is an Org export backend.  DESCRIPTION may be nil.  PROTOCOL may be one
+of gemini, gopher or finger."
+  (let* ((url (if (equal protocol "elpher")
+                  (string-remove-prefix "elpher:" link)
+                (format "%s:%s" protocol link)))
+         (desc (or description url)))
+    (pcase format
+      (`gemini (format "=> %s %s" url desc))
+      (`html (format "<a href=\"%s\">%s</a>" url desc))
+      (`latex (format "\\href{%s}{%s}" url desc))
+      (_ (if (not description)
+             url
+           (format "%s (%s)" desc url))))))
+
+(defun elpher-org-store-link ()
+  "Store link to an `elpher' page in Org."
+  (when (eq major-mode 'elpher-mode)
+    (let* ((url (elpher-info-current))
+           (desc (car elpher-current-page))
+           (protocol (cond
+                      ((string-prefix-p "gemini:" url) "gemini")
+                      ((string-prefix-p "gopher:" url) "gopher")
+                      ((string-prefix-p "finger:" url) "finger")
+                      (t "elpher"))))
+      (when (equal "elpher" protocol)
+        ;; Weird link. Or special inner link?
+        (setq url (concat "elpher:" url)))
+      (org-link-store-props :type protocol :link url :description desc)
+      t)))
+
+(defun elpher-org-follow-link (link protocol)
+  "Visit a LINK for the given PROTOCOL.
+
+PROTOCOL may be one of gemini, gopher or finger.  This method also
+supports the old protocol elpher, where the link is self-contained."
+  (let ((url (if (equal protocol "elpher")
+                 (string-remove-prefix "elpher:" link)
+               (format "%s:%s" protocol link))))
+    (elpher-go url)))
+
+(defun elpher-org-mode-integration ()
+  "Set up `elpher' integration for `org-mode'."
+  (org-link-set-parameters
+   "elpher"
+   :store #'elpher-org-store-link
+   :export (lambda (link description format _plist)
+             (elpher-org-export-link link description format "elpher"))
+   :follow (lambda (link _arg) (elpher-org-follow-link link "elpher")))
+  (org-link-set-parameters
+   "gemini"
+   :export (lambda (link description format _plist)
+             (elpher-org-export-link link description format "gemini"))
+   :follow (lambda (link _arg) (elpher-org-follow-link link "gemini")))
+  (org-link-set-parameters
+   "gopher"
+   :export (lambda (link description format _plist)
+             (elpher-org-export-link link description format "gopher"))
+   :follow (lambda (link _arg) (elpher-org-follow-link link "gopher")))
+  (org-link-set-parameters
+   "finger"
+   :export (lambda (link description format _plist)
+             (elpher-org-export-link link description format "finger"))
+   :follow (lambda (link _arg) (elpher-org-follow-link link "finger"))))
+
+(add-hook 'org-mode-hook #'elpher-org-mode-integration)
+
+;;; Browse URL
+
+;;;###autoload
+(defun elpher-browse-url-elpher (url &rest _args)
+  "Browse URL using Elpher.  This function is used by `browse-url'."
+  (interactive (browse-url-interactive-arg "Elpher URL: "))
+  (elpher-go url))
+
+;; Use elpher to open gopher, finger and gemini links
+;; For recent version of `browse-url' package
+(if (boundp 'browse-url-default-handlers)
+    (add-to-list
+     'browse-url-default-handlers
+     '("^\\(gopher\\|finger\\|gemini\\)://" . elpher-browse-url-elpher))
+  ;; Patch `browse-url-browser-function' for older ones. The value of
+  ;; that variable is `browse-url-default-browser' by default, so
+  ;; that's the function that gets advised.
+  (advice-add browse-url-browser-function :before-while
+              (lambda (url &rest _args)
+               "Handle gemini, gopher, and finger schemes using Elpher."
+                (let ((scheme (downcase (car (split-string url ":" t)))))
+                  (if (member scheme '("gemini" "gopher" "finger"))
+                      ;; `elpher-go' always returns nil, which will stop the
+                      ;; advice chain here in a before-while
+                      (elpher-go url)
+                    ;; chain must continue, then return t.
+                    t)))))
+
+;; Register "gemini://" as a URI scheme so `browse-url' does the right thing
+(with-eval-after-load 'thingatpt
+  (add-to-list 'thing-at-point-uri-schemes "gemini://"))
+
+;;; Mu4e:
+
+;; Make mu4e aware of the gemini world
+(setq mu4e~view-beginning-of-url-regexp
+      "\\(?:https?\\|gopher\\|finger\\|gemini\\)://\\|mailto:")

 
 ;;; Interactive procedures
 ;;
 
 ;;; Interactive procedures
 ;;


@@ -1546,25 +1942,27 @@ If ADDRESS is already bookmarked, update the label only."
   (interactive)
   (push-button))
 
   (interactive)
   (push-button))
 

+;;;###autoload

 (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* ((cleaned-host-or-url (string-trim host-or-url))
          (address (elpher-address-from-url cleaned-host-or-url))
 (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* ((cleaned-host-or-url (string-trim host-or-url))
          (address (elpher-address-from-url cleaned-host-or-url))

-         (page (elpher-make-page cleaned-host-or-url address))) 
-    (switch-to-buffer "*elpher*")
-    (elpher-visit-page page)
+         (page (elpher-make-page cleaned-host-or-url address)))
+    (switch-to-buffer elpher-buffer-name)
+    (elpher-with-clean-buffer
+     (elpher-visit-page page))

     nil))
 
 (defun elpher-go-current ()
   "Go to a particular site read from the minibuffer, initialized with the current URL."
   (interactive)
   (let ((address (elpher-page-address elpher-current-page)))
     nil))
 
 (defun elpher-go-current ()
   "Go to a particular site read from the minibuffer, initialized with the current URL."
   (interactive)
   (let ((address (elpher-page-address elpher-current-page)))

-    (if (elpher-address-special-p address)
-        (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)))))))
+    (let ((url (read-string "Gopher or Gemini URL: "
+                            (unless (elpher-address-special-p address)
+                              (elpher-address-to-url address)))))
+      (elpher-visit-page (elpher-make-page url (elpher-address-from-url url))))))

 
 (defun elpher-redraw ()
   "Redraw current page."
 
 (defun elpher-redraw ()
   "Redraw current page."


@@ -1603,11 +2001,9 @@ When run interactively HOST-OR-URL is read from the minibuffer."
 (defun elpher-back-to-start ()
   "Go all the way back to the start page."
   (interactive)
 (defun elpher-back-to-start ()
   "Go all the way back to the start page."
   (interactive)

-  (setq elpher-current-page nil)
-  (setq elpher-history nil)
-  (let ((start-page (elpher-make-page "Elpher Start Page"
-                                      (elpher-make-special-address 'start))))
-    (elpher-visit-page start-page)))
+  (setq-local elpher-current-page nil)
+  (setq-local elpher-history nil)
+  (elpher-visit-page (elpher-make-start-page)))

 
 (defun elpher-download ()
   "Download the link at point."
 
 (defun elpher-download ()
   "Download the link at point."


@@ -1671,73 +2067,6 @@ When run interactively HOST-OR-URL is read from the minibuffer."
             (elpher-go (elpher-address-to-url address-copy))))
       (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
 
             (elpher-go (elpher-address-to-url address-copy))))
       (error "Command invalid for %s" (elpher-page-display-string elpher-current-page)))))
 

-(defun elpher-bookmarks-current-p ()
-  "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 page is a bookmarks page."
-  (if (elpher-bookmarks-current-p)
-      (elpher-reload-current-page)))
-
-(defun elpher-bookmark-current ()
-  "Bookmark the current page."
-  (interactive)
-  (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)))
-          (elpher-add-address-bookmark address bookmark-display-string)
-          (message "Bookmark added."))
-      (error "Cannot bookmark %s" display-string))))
-
-(defun elpher-bookmark-link ()
-  "Bookmark the link at point."
-  (interactive)
-  (let ((button (button-at (point))))
-    (if button
-        (let* ((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)))
-                (elpher-add-address-bookmark address bookmark-display-string)
-                (elpher-reload-bookmarks)
-                (message "Bookmark added."))
-            (error "Cannot bookmark %s" display-string)))
-      (error "No link selected"))))
-
-(defun elpher-unbookmark-current ()
-  "Remove bookmark for the current page."
-  (interactive)
-  (let ((address (elpher-page-address elpher-current-page)))
-    (when (and (not (elpher-address-special-p address))
-               (y-or-n-p "Really remove bookmark for the current page? "))
-      (elpher-remove-address-bookmark address)
-      (message "Bookmark removed."))))
-
-(defun elpher-unbookmark-link ()
-  "Remove bookmark for the link at point."
-  (interactive)
-  (let ((button (button-at (point))))
-    (if button
-        (when (y-or-n-p "Really remove bookmark for this link? ")
-          (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"))))
-
-(defun elpher-bookmarks ()
-  "Visit bookmarks page."
-  (interactive)
-  (switch-to-buffer "*elpher*")
-  (elpher-visit-page
-   (elpher-make-page "Bookmarks Page" (elpher-make-special-address 'bookmarks))))
-

 (defun elpher-info-page (page)
   "Display information on PAGE."
   (let ((display-string (elpher-page-display-string page))
 (defun elpher-info-page (page)
   "Display information on PAGE."
   (let ((display-string (elpher-page-display-string page))


@@ -1753,7 +2082,7 @@ When run interactively HOST-OR-URL is read from the minibuffer."
     (if button
         (elpher-info-page (button-get button 'elpher-page))
       (error "No item selected"))))
     (if button
         (elpher-info-page (button-get button 'elpher-page))
       (error "No item selected"))))

-  
+

 (defun elpher-info-current ()
   "Display information on current page."
   (interactive)
 (defun elpher-info-current ()
   "Display information on current page."
   (interactive)


@@ -1800,11 +2129,15 @@ When run interactively HOST-OR-URL is read from the minibuffer."
     (define-key map (kbd "<backtab>") 'elpher-prev-link)
     (define-key map (kbd "C-M-i") 'elpher-prev-link)
     (define-key map (kbd "u") 'elpher-back)
     (define-key map (kbd "<backtab>") 'elpher-prev-link)
     (define-key map (kbd "C-M-i") 'elpher-prev-link)
     (define-key map (kbd "u") 'elpher-back)

-    (define-key map (kbd "U") 'elpher-back-to-start)
+    (define-key map (kbd "-") 'elpher-back)
+    (define-key map (kbd "^") 'elpher-back)

     (define-key map [mouse-3] 'elpher-back)
     (define-key map [mouse-3] 'elpher-back)

-    (define-key map (kbd "O") 'elpher-root-dir)
+    (define-key map (kbd "U") 'elpher-back-to-start)

     (define-key map (kbd "g") 'elpher-go)
     (define-key map (kbd "o") 'elpher-go-current)
     (define-key map (kbd "g") 'elpher-go)
     (define-key map (kbd "o") 'elpher-go-current)

+    (define-key map (kbd "O") 'elpher-root-dir)
+    (define-key map (kbd "s") 'elpher-show-history)
+    (define-key map (kbd "S") 'elpher-show-visited-pages)

     (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 "r") 'elpher-redraw)
     (define-key map (kbd "R") 'elpher-reload)
     (define-key map (kbd "T") 'elpher-toggle-tls)


@@ -1816,39 +2149,43 @@ When run interactively HOST-OR-URL is read from the minibuffer."
     (define-key map (kbd "I") 'elpher-info-current)
     (define-key map (kbd "c") 'elpher-copy-link-url)
     (define-key map (kbd "C") 'elpher-copy-current-url)
     (define-key map (kbd "I") 'elpher-info-current)
     (define-key map (kbd "c") 'elpher-copy-link-url)
     (define-key map (kbd "C") 'elpher-copy-current-url)

-    (define-key map (kbd "a") 'elpher-bookmark-link)
-    (define-key map (kbd "A") 'elpher-bookmark-current)
-    (define-key map (kbd "x") 'elpher-unbookmark-link)
-    (define-key map (kbd "X") 'elpher-unbookmark-current)
-    (define-key map (kbd "B") 'elpher-bookmarks)
-    (define-key map (kbd "S") 'elpher-set-gopher-coding-system)
+    (define-key map (kbd "a") 'elpher-set-bookmark-no-overwrite)
+    (define-key map (kbd "A") 'bookmark-set-no-overwrite)
+    (define-key map (kbd "B") 'bookmark-bmenu-list)
+    (define-key map (kbd "!") 'elpher-set-gopher-coding-system)
+    (define-key map (kbd "F") 'elpher-forget-current-certificate)

     (when (fboundp 'evil-define-key*)
     (when (fboundp 'evil-define-key*)

-      (evil-define-key* 'motion map
-        (kbd "TAB") 'elpher-next-link
-        (kbd "C-") 'elpher-follow-current-link
-        (kbd "C-t") 'elpher-back
-        (kbd "u") 'elpher-back
-        (kbd "U") 'elpher-back-to-start
-        [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 ".") 'elpher-view-raw
-        (kbd "d") 'elpher-download
-        (kbd "D") 'elpher-download-current
-        (kbd "m") 'elpher-jump
-        (kbd "i") 'elpher-info-link
-        (kbd "I") 'elpher-info-current
-        (kbd "c") 'elpher-copy-link-url
-        (kbd "C") 'elpher-copy-current-url
-        (kbd "a") 'elpher-bookmark-link
-        (kbd "A") 'elpher-bookmark-current
-        (kbd "x") 'elpher-unbookmark-link
-        (kbd "X") 'elpher-unbookmark-current
-        (kbd "B") 'elpher-bookmarks
-        (kbd "S") 'elpher-set-gopher-coding-system))
+      (evil-define-key*
+       'motion map
+       (kbd "TAB") 'elpher-next-link
+       (kbd "C-") 'elpher-follow-current-link
+       (kbd "C-t") 'elpher-back
+       (kbd "u") 'elpher-back
+       (kbd "-") 'elpher-back
+       (kbd "^") 'elpher-back
+       [mouse-3] 'elpher-back
+       (kbd "U") 'elpher-back-to-start
+       (kbd "g") 'elpher-go
+       (kbd "o") 'elpher-go-current
+       (kbd "O") 'elpher-root-dir
+       (kbd "s") 'elpher-show-history
+       (kbd "S") 'elpher-show-visited-pages
+       (kbd "r") 'elpher-redraw
+       (kbd "R") 'elpher-reload
+       (kbd "T") 'elpher-toggle-tls
+       (kbd ".") 'elpher-view-raw
+       (kbd "d") 'elpher-download
+       (kbd "D") 'elpher-download-current
+       (kbd "m") 'elpher-jump
+       (kbd "i") 'elpher-info-link
+       (kbd "I") 'elpher-info-current
+       (kbd "c") 'elpher-copy-link-url
+       (kbd "C") 'elpher-copy-current-url
+       (kbd "a") 'elpher-set-bookmark-no-overwrite
+       (kbd "A") 'bookmark-set-no-overwrite
+       (kbd "B") 'bookmark-bmenu-list
+       (kbd "!") 'elpher-set-gopher-coding-system
+       (kbd "F") 'elpher-forget-current-certificate))

     map)
   "Keymap for gopher client.")
 
     map)
   "Keymap for gopher client.")
 


@@ -1856,8 +2193,14 @@ When run interactively HOST-OR-URL is read from the minibuffer."
   "Major mode for elpher, an elisp gopher client.
 
 This mode is automatically enabled by the interactive
   "Major mode for elpher, an elisp gopher client.
 
 This mode is automatically enabled by the interactive

-functions which initialize the gopher client, namely
-`elpher', `elpher-go' and `elpher-bookmarks'.")
+functions which initialize the client, namely
+`elpher', and `elpher-go'."
+  (setq-local elpher--gemini-page-headings nil)
+  (setq-local elpher-current-page nil)
+  (setq-local elpher-history nil)
+  (setq-local elpher-buffer-name (buffer-name))
+  (setq-local bookmark-make-record-function #'elpher-bookmark-make-record)
+  (setq-local imenu-create-index-function (lambda () elpher--gemini-page-headings)))

 
 (when (fboundp 'evil-set-initial-state)
   (evil-set-initial-state 'elpher-mode 'motion))
 
 (when (fboundp 'evil-set-initial-state)
   (evil-set-initial-state 'elpher-mode 'motion))


@@ -1867,17 +2210,27 @@ functions which initialize the gopher client, namely
 ;;
 
 ;;;###autoload
 ;;
 
 ;;;###autoload

-(defun elpher ()
-  "Start elpher with default landing page."
-  (interactive)
-  (if (get-buffer "*elpher*")
-      (switch-to-buffer "*elpher*")
-    (switch-to-buffer "*elpher*")
-    (setq elpher-current-page nil)
-    (setq elpher-history 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.
+(defun elpher (&optional arg)
+  "Start elpher with default landing page.
+The buffer used for Elpher sessions is determined by the value of
+‘elpher-buffer-name’.  If there is already an Elpher session active in
+that buffer, Emacs will simply switch to it.  Otherwise, a new session
+will begin.  A numeric prefix ARG (as in ‘\\[universal-argument] 42
+\\[execute-extended-command] elpher RET’) switches to the session with
+that number, creating it if necessary.  A non numeric prefix ARG means
+to create a new session.  Returns the buffer selected (or created)."
+  (interactive "P")
+  (let* ((name (default-value 'elpher-buffer-name))
+         (buf (cond ((numberp arg)
+                     (get-buffer-create (format "%s<%d>" name arg)))
+                    (arg
+                     (generate-new-buffer name))
+                    (t
+                     (get-buffer-create name)))))
+    (pop-to-buffer-same-window buf)
+    (unless (buffer-modified-p)
+      (elpher-mode)
+      (elpher-visit-page (elpher-make-start-page))
+      "Started Elpher."))); Otherwise (elpher) evaluates to start page string.

 
 ;;; elpher.el ends here
 
 ;;; elpher.el ends here