elpher-go now trims surrounding whitespace from input string.
[elpher.git] / elpher.el
index 13ec53c..1ea9e71 100644 (file)
--- a/elpher.el
+++ b/elpher.el
@@ -1,10 +1,10 @@
-;;; elpher.el --- A friendly gopher client  -*- lexical-binding:t -*-
+;;; elpher.el --- A friendly gopher and gemini client  -*- lexical-binding:t -*-
 
 ;; Copyright (C) 2019 Tim Vaughan
 
-;; Author: Tim Vaughan <timv@ughan.xyz>
+;; Author: Tim Vaughan <plugd@thelambdalab.xyz>
 ;; Created: 11 April 2019
-;; Version: 2.6.0
+;; Version: 2.7.9
 ;; Keywords: comm gopher
 ;; Homepage: http://thelambdalab.xyz/elpher
 ;; Package-Requires: ((emacs "26"))
@@ -26,8 +26,8 @@
 
 ;;; Commentary:
 
-;; Elpher aims to provide a practical and friendly gopher client
-;; for GNU Emacs.  It supports:
+;; Elpher aims to provide a practical and friendly gopher and gemini
+;; client for GNU Emacs.  It supports:
 
 ;; - intuitive keyboard and mouse-driven browsing,
 ;; - out-of-the-box compatibility with evil-mode,
@@ -36,7 +36,7 @@
 ;; - pleasant and configurable colouring of Gopher directories,
 ;; - direct visualisation of image files,
 ;; - a simple bookmark management system,
-;; - connections using TLS encryption,
+;; - gopher connections using TLS encryption,
 ;; - the fledgling Gemini protocol,
 ;; - the greybeard Finger protocol.
 
 (require 'subr-x)
 (require 'dns)
 (require 'ansi-color)
+(require 'nsm)
 
 
 ;;; Global constants
 ;;
 
-(defconst elpher-version "2.6.0"
+(defconst elpher-version "2.7.9"
   "Current version of elpher.")
 
 (defconst elpher-margin-width 6
   "A gopher client."
   :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."
+  :type '(boolean))
+
+(defcustom elpher-use-header t
+  "If non-nil, display current page information in buffer header."
+  :type '(boolean))
+
+(defcustom elpher-auto-disengage-TLS nil
+  "If non-nil, automatically disengage TLS following an unsuccessful connection.
+While enabling this may seem convenient, it is also potentially dangerous as it
+allows switching from an encrypted channel back to plain text without user input."
+  :type '(boolean))
+
+(defcustom elpher-connection-timeout 5
+  "Specifies the number of seconds to wait for a network connection to time out."
+  :type '(integer))
+
+(defcustom elpher-filter-ansi-from-text nil
+  "If non-nil, filter ANSI escape sequences from text.
+The default behaviour is to use the ansi-color package to interpret these
+sequences."
+  :type '(boolean))
+
+(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.
+
+This defaults to off because it is standard practice for Gemini servers
+to use self-signed certificates, meaning that most servers provide what
+EMACS considers to be an invalid certificate."
+  :type '(boolean))
+
+(defcustom elpher-gemini-max-fill-width 80
+  "Specify the maximum default width (in columns) of text/gemini documents.
+The actual width used is the minimum of this value and the window width at
+the time when the text is rendered."
+  :type '(integer))
+
+(defcustom elpher-gemini-link-string "→ "
+  "Specify the string used to indicate links when rendering gemini maps.
+May be empty."
+  :type '(string))
+
+(defcustom elpher-gemini-bullet-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))
+
 ;; Face customizations
 
+(defgroup elpher-faces nil
+  "Elpher face customizations."
+  :group 'elpher)
+
 (defface elpher-index
   '((t :inherit font-lock-keyword-face))
   "Face used for directory type directory records.")
 
 (defface elpher-gemini
   '((t :inherit font-lock-regexp-grouping-backslash))
-  "Face used for html type directory records.")
+  "Face used for Gemini type directory records.")
 
 (defface elpher-other-url
   '((t :inherit font-lock-comment-face))
   '((t :inherit shadow))
   "Face used for brackets around directory margin key.")
 
-;; Other customizations
+(defface elpher-gemini-heading1
+  '((t :inherit bold :height 1.8))
+  "Face used for gemini heading level 1.")
 
-(defcustom elpher-open-urls-with-eww nil
-  "If non-nil, open URL selectors using eww.
-Otherwise, use the system browser via the BROWSE-URL function."
-  :type '(boolean))
+(defface elpher-gemini-heading2
+  '((t :inherit bold :height 1.5))
+  "Face used for gemini heading level 2.")
 
-(defcustom elpher-use-header t
-  "If non-nil, display current page information in buffer header."
-  :type '(boolean))
+(defface elpher-gemini-heading3
+  '((t :inherit bold :height 1.2))
+  "Face used for gemini heading level 3.")
 
-(defcustom elpher-auto-disengage-TLS nil
-  "If non-nil, automatically disengage TLS following an unsuccessful connection.
-While enabling this may seem convenient, it is also potentially dangerous as it
-allows switching from an encrypted channel back to plain text without user input."
-  :type '(boolean))
-
-(defcustom elpher-connection-timeout 5
-  "Specifies the number of seconds to wait for a network connection to time out."
-  :type '(integer))
-
-(defcustom elpher-filter-ansi-from-text nil
-  "If non-nil, filter ANSI escape sequences from text.
-The default behaviour is to use the ansi-color package to interpret these
-sequences."
-  :type '(boolean))
+(defface elpher-gemini-preformatted
+  '((t :inherit fixed-pitch))
+  "Face used for pre-formatted gemini text blocks.")
 
 ;;; Model
 ;;
@@ -229,6 +284,7 @@ The basic attributes include: TYPE, SELECTOR, HOST and PORT.
 If the optional attribute TLS is non-nil, the address will be marked as
 requiring gopher-over-TLS."
   (cond
+   ((equal type ?i) nil)
    ((and (equal type ?h)
          (string-prefix-p "URL:" selector))
     (elpher-address-from-url (elt (split-string selector "URL:") 1)))
@@ -251,9 +307,25 @@ requiring gopher-over-TLS."
 
 (defun elpher-address-to-url (address)
   "Get string representation of ADDRESS, or nil if ADDRESS is special."
-  (if (not (elpher-address-special-p address))
-      (url-encode-url (url-recreate-url address))
-    nil))
+  (if (elpher-address-special-p address)
+      nil
+    (let* ((port (url-port address))
+           (address-to-convert
+            (if (= port 0)
+                address
+              (let ((address-copy (seq-copy address))
+                    (protocol (url-type address)))
+                (if (or (and (equal protocol "gopher")
+                             (= port 70))
+                        (and (equal protocol "gemini")
+                             (= port 1965))
+                        (and (equal protocol "http")
+                             (= port 80))
+                        (and (equal protocol "finger")
+                             (= port 79)))
+                    (setf (url-port address-copy) 0))
+                address-copy))))
+      (url-encode-url (url-recreate-url address-to-convert)))))
 
 (defun elpher-address-type (address)
   "Retrieve type of ADDRESS object.
@@ -317,7 +389,7 @@ If no address is defined, returns 0.  (This is for compatibility with the URL li
   "Retrieve gopher selector from ADDRESS object."
   (if (member (url-filename address) '("" "/"))
       ""
-    (substring (url-filename address) 2)))
+    (url-unhex-string (substring (url-filename address) 2))))
 
 
 ;; Cache
@@ -356,6 +428,10 @@ If no address is defined, returns 0.  (This is for compatibility with the URL li
   "Retrieve the address corresponding to PAGE."
   (elt page 1))
 
+(defun elpher-page-set-address (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)
 
@@ -392,7 +468,7 @@ unless NO-HISTORY is non-nil."
   (let ((previous-page (pop elpher-history)))
     (if previous-page
         (elpher-visit-page previous-page nil t)
-      (error "No previous page."))))
+      (error "No previous page"))))
       
 (defun elpher-reload-current-page ()
   "Reload the current page, discarding any existing cached content."
@@ -434,6 +510,8 @@ unless NO-HISTORY is non-nil."
   (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)))
@@ -502,14 +580,20 @@ to ADDRESS."
       (error "Cannot retrieve TLS gopher selector: GnuTLS not available")))
   (unless (< (elpher-address-port address) 65536)
     (error "Cannot retrieve gopher selector: port number > 65536"))
+  (defvar gnutls-verify-error)
   (condition-case nil
       (let* ((kill-buffer-query-functions nil)
+             (gnutls-verify-error nil) ; We use the NSM for verification
              (port (elpher-address-port address))
              (host (elpher-address-host address))
-             (selector-string "")
+             (selector-string-parts nil)
+             (bytes-received 0)
+             (hkbytes-received 0)
              (proc (open-network-stream "elpher-process"
                                         nil
-                                        (if force-ipv4 (dns-query host) host)
+                                        (if (or elpher-ipv4-always force-ipv4)
+                                            (dns-query host)
+                                          host)
                                         (if (> port 0) port 70)
                                         :type (if elpher-use-tls 'tls 'plain)
                                         :nowait t))
@@ -530,16 +614,30 @@ to ADDRESS."
                                         (elpher-network-error address "Could not establish encrypted connection")))
                                      ('connect
                                       (elpher-process-cleanup)
-                                      (unless force-ipv4
+                                      (unless (or elpher-ipv4-always force-ipv4)
                                         (message "Connection timed out. Retrying with IPv4 address.")
                                         (elpher-get-selector address renderer t))))))))
         (setq elpher-network-timer timer)
         (set-process-coding-system proc 'binary)
         (set-process-filter proc
                             (lambda (_proc string)
-                              (cancel-timer timer)
-                              (setq selector-string
-                                    (concat selector-string string))))
+                              (when timer
+                                (cancel-timer timer)
+                                (setq timer nil))
+                              (setq bytes-received (+ bytes-received (length string)))
+                              (let ((new-hkbytes-received (/ bytes-received 102400)))
+                                (when (> new-hkbytes-received hkbytes-received)
+                                  (setq hkbytes-received new-hkbytes-received)
+                                  (with-current-buffer "*elpher*"
+                                    (let ((inhibit-read-only t))
+                                      (goto-char (point-min))
+                                      (beginning-of-line 2)
+                                      (delete-region (point) (point-max))
+                                      (insert "("
+                                              (number-to-string (/ hkbytes-received 10.0))
+                                              " MB read)")))))
+                              (setq selector-string-parts
+                                    (cons string selector-string-parts))))
         (set-process-sentinel proc
                               (lambda (_proc event)
                                 (condition-case the-error
@@ -552,8 +650,11 @@ to ADDRESS."
                                          (concat (elpher-gopher-address-selector address)
                                                  "\r\n"))))
                                      (t
-                                      (cancel-timer timer)
-                                      (funcall renderer selector-string)
+                                      (when timer
+                                        (cancel-timer timer)
+                                        (setq timer nil))
+                                      (funcall renderer (apply #'concat
+                                                               (reverse selector-string-parts)))
                                       (elpher-restore-pos)))
                                   (error
                                    (elpher-network-error address the-error))))))
@@ -571,7 +672,7 @@ once they are retrieved from the gopher server."
          (insert content)
          (elpher-restore-pos))
       (elpher-with-clean-buffer
-       (insert "LOADING... (use 'u' to cancel)"))
+       (insert "LOADING... (use 'u' to cancel)\n"))
       (condition-case the-error
           (elpher-get-selector address renderer)
         (error
@@ -610,12 +711,19 @@ once they are retrieved from the gopher server."
         (insert " "))
     (insert (make-string elpher-margin-width ?\s))))
 
-(defun elpher-page-button-help (page)
-  "Return a string containing the help text for a button corresponding to PAGE."
-  (let ((address (elpher-page-address page)))
-    (format "mouse-1, RET: open '%s'" (if (elpher-address-special-p address)
-                                          address
-                                        (elpher-address-to-url address)))))
+(defun elpher--page-button-help (_window buffer pos)
+  "Function called by Emacs to generate mouse-over text.
+The arguments specify the BUFFER and the POS within the buffer of the item
+for which help is required.  The function returns the help to be
+displayed.  The _WINDOW argument is currently unused."
+  (with-current-buffer buffer
+    (let ((button (button-at pos)))
+      (when button
+        (let* ((page (button-get button 'elpher-page))
+               (address (elpher-page-address page)))
+          (format "mouse-1, RET: open '%s'" (if (elpher-address-special-p address)
+                                                address
+                                              (url-recreate-url address))))))))
 
 (defun elpher-insert-index-record (display-string &optional address)
   "Function to insert an index record into the current buffer.
@@ -635,9 +743,9 @@ If ADDRESS is not supplied or nil the record is rendered as an
                               'elpher-page page
                               'action #'elpher-click-link
                               'follow-link t
-                              'help-echo (elpher-page-button-help page)))
+                              'help-echo #'elpher--page-button-help))
       (pcase type
-        ((or '(gopher ?i) 'nil) ;; Information
+        ('nil ;; Information
          (elpher-insert-margin)
          (let ((propertized-display-string
                 (propertize display-string 'face 'elpher-info)))
@@ -681,7 +789,7 @@ If ADDRESS is not supplied or nil the record is rendered as an
                             'elpher-page  page
                             'action #'elpher-click-link
                             'follow-link t
-                            'help-echo (elpher-page-button-help page)
+                            'help-echo #'elpher--page-button-help
                             'face 'button)))
     (buffer-string)))
 
@@ -770,7 +878,9 @@ The response is rendered using the rendering function RENDERER."
   (if (not data)
       nil
     (let* ((address (elpher-page-address elpher-current-page))
-           (selector (elpher-gopher-address-selector address)))
+           (selector (if (elpher-address-gopher-p address)
+                         (elpher-gopher-address-selector address)
+                       (elpher-address-filename address))))
       (elpher-visit-previous-page) ; Do first in case of non-local exits.
       (let* ((filename-proposal (file-name-nondirectory selector))
              (filename (read-file-name "Download complete. Save file as: "
@@ -803,25 +913,33 @@ The response is rendered using the rendering function RENDERER."
   "Retrieve gemini ADDRESS, then render using RENDERER.
 If FORCE-IPV4 is non-nil, explicitly look up and use IPv4 address corresponding
 to ADDRESS."
+  (unless elpher-gemini-TLS-cert-checks
+    (setq-local network-security-level 'low))
   (if (not (gnutls-available-p))
       (error "Cannot establish gemini connection: GnuTLS not available")
     (unless (< (elpher-address-port address) 65536)
       (error "Cannot establish gemini connection: port number > 65536"))
+    (defvar gnutls-verify-error)
     (condition-case nil
         (let* ((kill-buffer-query-functions nil)
+               (gnutls-verify-error nil) ; We use the NSM for verification
                (port (elpher-address-port address))
                (host (elpher-address-host address))
-               (response-string "")
+               (response-string-parts nil)
+               (bytes-received 0)
+               (hkbytes-received 0)
                (proc (open-network-stream "elpher-process"
                                           nil
-                                          (if force-ipv4 (dns-query host) host)
+                                          (if (or elpher-ipv4-always force-ipv4)
+                                              (dns-query host)
+                                            host)
                                           (if (> port 0) port 1965)
                                           :type 'tls
                                           :nowait t))
                (timer (run-at-time elpher-connection-timeout nil
                                    (lambda ()
                                      (elpher-process-cleanup)
-                                     (unless force-ipv4
+                                     (unless (or elpher-ipv4-always force-ipv4)
                                         ; Try again with IPv4
                                        (message "Connection timed out.  Retrying with IPv4.")
                                        (elpher-get-gemini-response address renderer t))))))
@@ -832,8 +950,20 @@ to ADDRESS."
                                 (when timer
                                   (cancel-timer timer)
                                   (setq timer nil))
-                                (setq response-string
-                                      (concat response-string string))))
+                                (setq bytes-received (+ bytes-received (length string)))
+                                (let ((new-hkbytes-received (/ bytes-received 102400)))
+                                  (when (> new-hkbytes-received hkbytes-received)
+                                    (setq hkbytes-received new-hkbytes-received)
+                                    (with-current-buffer "*elpher*"
+                                      (let ((inhibit-read-only t))
+                                        (goto-char (point-min))
+                                        (beginning-of-line 2)
+                                        (delete-region (point) (point-max))
+                                        (insert "("
+                                                (number-to-string (/ hkbytes-received 10.0))
+                                                " MB read)")))))
+                                (setq response-string-parts
+                                      (cons string response-string-parts))))
           (set-process-sentinel proc
                                 (lambda (proc event)
                                   (condition-case the-error
@@ -845,19 +975,19 @@ to ADDRESS."
                                            (concat (elpher-address-to-url address)
                                                    "\r\n"))))
                                        ((string-prefix-p "deleted" event)) ; do nothing
-                                       ((and (string-empty-p response-string)
-                                             (not force-ipv4))
+                                       ((and (not response-string-parts)
+                                             (not (or elpher-ipv4-always force-ipv4)))
                                         ; Try again with IPv4
                                         (message "Connection failed. Retrying with IPv4.")
                                         (cancel-timer timer)
                                         (elpher-get-gemini-response address renderer t))
                                        (t
                                         (funcall #'elpher-process-gemini-response
-                                                 response-string
+                                                 (apply #'concat (reverse response-string-parts))
                                                  renderer)
                                         (elpher-restore-pos)))
                                     (error
-                                           (elpher-network-error address the-error))))))
+                                     (elpher-network-error address the-error))))))
       (error
        (error "Error initiating connection to server")))))
 
@@ -874,7 +1004,7 @@ that the response was malformed."
                     (meta (string-trim (substring header 2))))
                 (list code meta body))
             (error "Malformed response: No response status found in header %s" header)))
-      (error "Malformed response: No CRLF-delimited header found"))))
+      (error "Malformed response: No CRLF-delimited header found in response %s" response))))
 
 (defun elpher-process-gemini-response (response-string renderer)
   "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
@@ -903,6 +1033,7 @@ that the response was malformed."
                              "gemini"))
                (error "Server tried to automatically redirect to non-gemini URL: %s"
                       response-meta))
+           (elpher-page-set-address elpher-current-page redirect-address)
            (add-to-list 'elpher-gemini-redirect-chain redirect-address)
            (elpher-get-gemini-response redirect-address renderer)))
         (?4 ; Temporary failure
@@ -927,7 +1058,7 @@ that the response was malformed."
               (insert content)
               (elpher-restore-pos))
           (elpher-with-clean-buffer
-           (insert "LOADING GEMINI... (use 'u' to cancel)"))
+           (insert "LOADING GEMINI... (use 'u' to cancel)\n"))
           (setq elpher-gemini-redirect-chain nil)
           (elpher-get-gemini-response address renderer))
       (error
@@ -966,19 +1097,25 @@ that the response was malformed."
         ((pred (string-prefix-p "image/"))
          (elpher-render-image body))
         (_other
-         (error "Unsupported MIME type %S" mime-type))))))
-
-(defun elpher-gemini-get-link-url (line)
-  "Extract the url portion of LINE, a gemini map file link line."
-  (string-trim (elt (split-string (substring line 2)) 0)))
-
-(defun elpher-gemini-get-link-display-string (line)
-  "Extract the display string portion of LINE, a gemini map file link line."
-  (let* ((rest (string-trim (elt (split-string line "=>") 1)))
+         (elpher-render-download body))))))
+
+(defun elpher-gemini-get-link-url (link-line)
+  "Extract the url portion of LINK-LINE, a gemini map file link line.
+Returns nil in the event that the contents of the line following the
+=> prefix are empty."
+  (let ((l (split-string (substring link-line 2))))
+    (if l
+        (string-trim (elt l 0))
+      nil)))
+
+(defun elpher-gemini-get-link-display-string (link-line)
+  "Extract the display string portion of LINK-LINE, a gemini map file link line.
+Returns the url portion in the event that the display-string portion is empty."
+  (let* ((rest (string-trim (elt (split-string link-line "=>") 1)))
          (idx (string-match "[ \t]" rest)))
-    (if idx
-        (string-trim (substring rest (+ idx 1)))
-      "")))
+    (string-trim (if idx
+                     (substring rest (+ idx 1))
+                   rest))))
 
 (defun elpher-collapse-dot-sequences (filename)
   "Collapse dot sequences in FILENAME.
@@ -995,17 +1132,18 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
 
 (defun elpher-address-from-gemini-url (url)
   "Extract address from URL with defaults as per gemini map files."
-  (let ((address (url-generic-parse-url url)))
+  (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
       (setf (url-fullness address) t)
       (if (url-host address) ;if there is an explicit host, filenames are absolute
           (if (string-empty-p (url-filename address))
               (setf (url-filename address) "/")) ;ensure empty filename is marked as absolute
-        (setf (url-host address) (url-host (elpher-page-address elpher-current-page)))
+        (setf (url-host address) (url-host current-address))
+        (setf (url-port address) (url-port current-address))
         (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
           (setf (url-filename address)
-                (concat (file-name-directory
-                         (url-filename (elpher-page-address elpher-current-page)))
+                (concat (file-name-directory (url-filename current-address))
                         (url-filename address)))))
       (unless (url-type address)
         (setf (url-type address) "gemini"))
@@ -1014,18 +1152,78 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
                 (elpher-collapse-dot-sequences (url-filename address)))))
     address))
 
+(defun elpher-gemini-insert-link (link-line)
+  "Insert link described by LINK-LINE into a text/gemini document."
+  (let* ((url (elpher-gemini-get-link-url link-line))
+         (display-string (elpher-gemini-get-link-display-string link-line))
+         (address (elpher-address-from-gemini-url url))
+         (type (if address (elpher-address-type address) nil))
+         (type-map-entry (cdr (assoc type elpher-type-map))))
+    (when display-string
+      (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))
+                 (page (elpher-make-page filtered-display-string address)))
+            (insert-text-button filtered-display-string
+                                'face face
+                                'elpher-page page
+                                'action #'elpher-click-link
+                                'follow-link t
+                                '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)
+    (let ((level (length (match-string 1 header-line)))
+          (header (substring header-line (match-end 0))))
+      (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"))))
+
+(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]\\)?" 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))
+         (fill-prefix (if (match-string 1 text-line)
+                          (replace-regexp-in-string "\*" " " (match-string 0 text-line))
+                        nil)))
+    (insert (elpher-process-text-for-display processed-text-line))
+    (newline)))
+
 (defun elpher-render-gemini-map (data _parameters)
   "Render DATA as a gemini map file, PARAMETERS is currently unused."
   (elpher-with-clean-buffer
-   (dolist (line (split-string data "\n"))
-     (if (string-prefix-p "=>" line)
-         (let* ((url (elpher-gemini-get-link-url line))
-                (display-string (elpher-gemini-get-link-display-string line))
-                (address (elpher-address-from-gemini-url url)))
-           (if (> (length display-string) 0)
-               (elpher-insert-index-record display-string address)
-             (elpher-insert-index-record url address)))
-       (elpher-insert-index-record line)))
+   (let ((preformatted nil))
+     (auto-fill-mode 1)
+     (setq-local fill-column (min (window-width) elpher-gemini-max-fill-width))
+     (dolist (line (split-string data "\n"))
+       (cond
+        ((string-prefix-p "```" line) (setq preformatted (not preformatted)))
+        (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-header line))
+        (t (elpher-gemini-insert-text line)))))
    (elpher-cache-content
     (elpher-page-address elpher-current-page)
     (buffer-string))))
@@ -1041,7 +1239,11 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
 ;; Finger page connection
 
 (defun elpher-get-finger-page (renderer &optional force-ipv4)
-  "Opens a finger connection to the current page address and renders it using RENDERER."
+  "Opens a finger connection to the current page address.
+The result is rendered using RENDERER.  When the optional argument
+FORCE-IPV4 or the variable `elpher-ipv4-always' are non-nil, the
+IPv4 address returned by a DNS lookup will be used explicitly in
+making the connection."
   (let* ((address (elpher-page-address elpher-current-page))
          (content (elpher-get-cached-content address)))
     (if (and content (funcall renderer nil))
@@ -1049,7 +1251,7 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
          (insert content)
          (elpher-restore-pos))
       (elpher-with-clean-buffer
-       (insert "LOADING... (use 'u' to cancel)"))
+       (insert "LOADING... (use 'u' to cancel)\n"))
       (condition-case the-error
           (let* ((kill-buffer-query-functions nil)
                  (user (let ((filename (elpher-address-filename address)))
@@ -1059,10 +1261,12 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
                  (port (let ((given-port (elpher-address-port address)))
                          (if (> given-port 0) given-port 79)))
                  (host (elpher-address-host address))
-                 (selector-string "")
+                 (selector-string-parts nil)
                  (proc (open-network-stream "elpher-process"
                                             nil
-                                            (if force-ipv4 (dns-query host) host)
+                                            (if (or elpher-ipv4-always force-ipv4)
+                                                (dns-query host)
+                                              host)
                                             port
                                             :type 'plain
                                             :nowait t))
@@ -1072,19 +1276,21 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
                                        (pcase (process-status proc)
                                          ('connect
                                           (elpher-process-cleanup)
-                                          (unless force-ipv4
+                                          (unless (or elpher-ipv4-always force-ipv4)
                                             (message "Connection timed out. Retrying with IPv4 address.")
                                             (elpher-get-finger-page renderer t))))))))
             (setq elpher-network-timer timer)
             (set-process-coding-system proc 'binary)
             (set-process-filter proc
                                 (lambda (_proc string)
-                                  (cancel-timer timer)
-                                  (setq selector-string
-                                        (concat selector-string string))))
+                                  (when timer
+                                    (cancel-timer timer)
+                                    (setq timer nil))
+                                  (setq selector-string-parts
+                                        (cons string selector-string-parts))))
             (set-process-sentinel proc
                                   (lambda (_proc event)
-                                    (condition-case the-error
+                                    (condition-case _the-error
                                         (cond
                                          ((string-prefix-p "deleted" event))
                                          ((string-prefix-p "open" event)
@@ -1093,8 +1299,11 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
                                              proc
                                              (concat user "\r\n"))))
                                          (t
-                                          (cancel-timer timer)
-                                          (funcall renderer selector-string)
+                                          (when timer
+                                            (cancel-timer timer)
+                                            (setq timer nil))
+                                          (funcall renderer (apply #'concat
+                                                                   (reverse selector-string-parts)))
                                           (elpher-restore-pos)))))))
         (error
          (elpher-network-error address the-error))))))
@@ -1140,7 +1349,7 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
     (error "Command not supported for start page"))
   (elpher-with-clean-buffer
    (insert "     --------------------------------------------\n"
-           "                Elpher Gopher Client             \n"
+           "           Elpher Gopher and Gemini Client       \n"
            "                   version " elpher-version "\n"
            "     --------------------------------------------\n"
            "\n"
@@ -1149,9 +1358,9 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
            " - TAB/Shift-TAB: next/prev item on current page\n"
            " - RET/mouse-1: open item under cursor\n"
            " - m: select an item on current page by name (autocompletes)\n"
-           " - u/mouse-3: return to previous page\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 gopher address\n"
+           " - g: go to a particular address (gopher, gemini, finger)\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"
@@ -1164,13 +1373,17 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
            " - T: toggle TLS gopher mode\n"
            " - .: display the raw server response for the current page\n"
            "\n"
-           "Start your exploration of gopher space:\n")
+           "Start your exploration of gopher space and gemini:\n")
    (elpher-insert-index-record "Floodgap Systems Gopher Server"
                                (elpher-make-gopher-address ?1 "" "gopher.floodgap.com" 70))
+   (elpher-insert-index-record "Project Gemini home page"
+                               (elpher-address-from-url "gemini://gemini.circumlunar.space/"))
    (insert "\n"
-           "Alternatively, select the following item and enter some search terms:\n")
-   (elpher-insert-index-record "Veronica-2 Gopher Search Engine"
+           "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"))
    (insert "\n"
            "This page contains your bookmarked sites (also visit with B):\n")
    (elpher-insert-index-record "Your Bookmarks" 'bookmarks)
@@ -1221,7 +1434,7 @@ For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
            "- a: rename selected bookmark\n"
            "\n"
            "Bookmarks are stored in the file ")
-   (let ((filename (locate-user-emacs-file "elpher-bookmarks"))
+   (let ((filename elpher-bookmarks-file)
          (help-string "RET,mouse-1: Open bookmarks file in new buffer for editing."))
      (insert-text-button filename
                          'face 'link
@@ -1258,7 +1471,7 @@ bookmark list, while URL is the url of the entry."
 (defun elpher-save-bookmarks (bookmarks)
   "Record the bookmark list BOOKMARKS to the user's bookmark file.
 Beware that this completely replaces the existing contents of the file."
-  (with-temp-file (locate-user-emacs-file "elpher-bookmarks")
+  (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"
@@ -1271,7 +1484,7 @@ Beware that this completely replaces the existing contents of the file."
   (let ((bookmarks
          (with-temp-buffer
            (ignore-errors
-             (insert-file-contents (locate-user-emacs-file "elpher-bookmarks"))
+             (insert-file-contents elpher-bookmarks-file)
              (goto-char (point-min))
              (read (current-buffer))))))
     (if (and bookmarks (listp (cadar bookmarks)))
@@ -1325,11 +1538,12 @@ If ADDRESS is already bookmarked, update the label only."
   "Go to a particular gopher site HOST-OR-URL.
 When run interactively HOST-OR-URL is read from the minibuffer."
   (interactive "sGopher or Gemini URL: ")
-  (let ((page (elpher-make-page host-or-url
-                                (elpher-address-from-url host-or-url))))
+  (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)
-    '()))
+    nil))
 
 (defun elpher-go-current ()
   "Go to a particular site read from the minibuffer, initialized with the current URL."
@@ -1374,6 +1588,15 @@ When run interactively HOST-OR-URL is read from the minibuffer."
   (interactive)
   (elpher-visit-previous-page))
 
+(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)))
+
 (defun elpher-download ()
   "Download the link at point."
   (interactive)
@@ -1433,9 +1656,7 @@ When run interactively HOST-OR-URL is read from the minibuffer."
           (let ((address-copy (elpher-address-from-url
                                (elpher-address-to-url address))))
             (setf (url-filename address-copy) "")
-            (elpher-visit-page
-             (elpher-make-page (elpher-address-to-url address-copy)
-                               address-copy))))
+            (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 ()
@@ -1481,7 +1702,8 @@ When run interactively HOST-OR-URL is read from the minibuffer."
   "Remove bookmark for the current page."
   (interactive)
   (let ((address (elpher-page-address elpher-current-page)))
-    (unless (elpher-address-special-p address)
+    (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."))))
 
@@ -1490,10 +1712,11 @@ When run interactively HOST-OR-URL is read from the minibuffer."
   (interactive)
   (let ((button (button-at (point))))
     (if button
-        (let ((page (button-get button 'elpher-page)))
-          (elpher-remove-address-bookmark (elpher-page-address page))
-          (elpher-reload-bookmarks)
-          (message "Bookmark removed."))
+        (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 ()
@@ -1563,7 +1786,9 @@ When run interactively HOST-OR-URL is read from the minibuffer."
   (let ((map (make-sparse-keymap)))
     (define-key map (kbd "TAB") 'elpher-next-link)
     (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 [mouse-3] 'elpher-back)
     (define-key map (kbd "O") 'elpher-root-dir)
     (define-key map (kbd "g") 'elpher-go)
@@ -1591,6 +1816,7 @@ When run interactively HOST-OR-URL is read from the minibuffer."
         (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
@@ -1636,6 +1862,7 @@ functions which initialize the gopher client, namely
       (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)))