Experimenting with asynchronous connections.

[elpher.git] / elpher.el

diff --git a/elpher.el b/elpher.el
index 244df40..db5a820 100644 (file)
--- a/elpher.el
+++ b/elpher.el
@@ -4,7 +4,7 @@
 
 ;; Author: Tim Vaughan <tgvaughan@gmail.com>
 ;; Created: 11 April 2019
 
 ;; Author: Tim Vaughan <tgvaughan@gmail.com>
 ;; Created: 11 April 2019

-;; Version: 2.0.1
+;; Version: 2.3.6

 ;; Keywords: comm gopher
 ;; Homepage: https://github.com/tgvaughan/elpher
 ;; Package-Requires: ((emacs "26"))
 ;; Keywords: comm gopher
 ;; Homepage: https://github.com/tgvaughan/elpher
 ;; Package-Requires: ((emacs "26"))


@@ -60,12 +60,13 @@
 (require 'shr)
 (require 'url-util)
 (require 'subr-x)
 (require 'shr)
 (require 'url-util)
 (require 'subr-x)

+(require 'dns)

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

-(defconst elpher-version "2.0.1"
+(defconst elpher-version "2.3.6"

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


@@ -77,7 +78,7 @@
     ((gopher ?4) elpher-get-gopher-node elpher-render-download "bin" elpher-binary)
     ((gopher ?5) elpher-get-gopher-node elpher-render-download "bin" elpher-binary)
     ((gopher ?7) elpher-get-gopher-query-node elpher-render-index "?" elpher-search)
     ((gopher ?4) elpher-get-gopher-node elpher-render-download "bin" elpher-binary)
     ((gopher ?5) elpher-get-gopher-node elpher-render-download "bin" elpher-binary)
     ((gopher ?7) elpher-get-gopher-query-node elpher-render-index "?" elpher-search)

-    ((gopher ?9) elpher-get-gopher-node elpher-render-node-download "bin" elpher-binary)
+    ((gopher ?9) elpher-get-gopher-node elpher-render-download "bin" elpher-binary)

     ((gopher ?g) elpher-get-gopher-node elpher-render-image "img" elpher-image)
     ((gopher ?p) elpher-get-gopher-node elpher-render-image "img" elpher-image)
     ((gopher ?I) elpher-get-gopher-node elpher-render-image "img" elpher-image)
     ((gopher ?g) elpher-get-gopher-node elpher-render-image "img" elpher-image)
     ((gopher ?p) elpher-get-gopher-node elpher-render-image "img" elpher-image)
     ((gopher ?I) elpher-get-gopher-node elpher-render-image "img" elpher-image)


@@ -88,7 +89,7 @@
     (gemini elpher-get-gemini-node elpher-render-gemini "gem" elpher-gemini)
     (telnet elpher-get-telnet-node nil "tel" elpher-telnet)
     (other-url elpher-get-other-url-node nil "url" elpher-other-url)
     (gemini elpher-get-gemini-node elpher-render-gemini "gem" elpher-gemini)
     (telnet elpher-get-telnet-node nil "tel" elpher-telnet)
     (other-url elpher-get-other-url-node nil "url" elpher-other-url)

-    ((special bookmarks) elpher-get-bookmarks-node nil)
+    ((special bookmarks) elpher-get-bookmarks-node nil "/" elpher-index)

     ((special start) elpher-get-start-node nil))
   "Association list from types to getters, renderers, margin codes and index faces.")
 
     ((special start) elpher-get-start-node nil))
   "Association list from types to getters, renderers, margin codes and index faces.")
 


@@ -161,7 +162,7 @@
 Otherwise, use the system browser via the BROWSE-URL function."
   :type '(boolean))
 
 Otherwise, use the system browser via the BROWSE-URL function."
   :type '(boolean))
 

-(defcustom elpher-buttonify-urls-in-directories nil
+(defcustom elpher-buttonify-urls-in-directories t

   "If non-nil, turns URLs matched in directories into clickable buttons."
   :type '(boolean))
 
   "If non-nil, turns URLs matched in directories into clickable buttons."
   :type '(boolean))
 


@@ -191,13 +192,14 @@ allows switching from an encrypted channel back to plain text without user input
   (let ((data (match-data))) ; Prevent parsing clobbering match data
     (unwind-protect
         (let ((url (url-generic-parse-url url-string)))
   (let ((data (match-data))) ; Prevent parsing clobbering match data
     (unwind-protect
         (let ((url (url-generic-parse-url url-string)))

-          (setf (url-fullness url) t)
-          (setf (url-filename url)
-                (url-unhex-string (url-filename url)))
-          (unless (url-type url)
-            (setf (url-type url) "gopher"))
-          (when (or (equal "gopher" (url-type url))
-                    (equal "gophers" (url-type url)))
+          (unless (and (not (url-fullness url)) (url-type url))
+            (setf (url-fullness url) t)
+            (setf (url-filename url)
+                  (url-unhex-string (url-filename url)))
+            (unless (url-type url)
+              (setf (url-type url) "gopher"))
+            (when (or (equal "gopher" (url-type url))
+                      (equal "gophers" (url-type url)))

               ;; Gopher defaults
               (unless (url-host url)
                 (setf (url-host url) (url-filename url))
               ;; Gopher defaults
               (unless (url-host url)
                 (setf (url-host url) (url-filename url))


@@ -205,6 +207,10 @@ allows switching from an encrypted channel back to plain text without user input
               (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")))

+            (when (equal "gemini" (url-type url))
+              ;; Gemini defaults
+              (if (equal (url-filename url) "")
+                  (setf (url-filename url) "/"))))

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


@@ -213,15 +219,22 @@ allows switching from an encrypted channel back to plain text without user input
 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."
 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."

-  (if (and (equal type ?h)
-           (string-prefix-p "URL:" selector))
-      (elpher-address-from-url (elt (split-string selector "URL:") 1))
+  (cond
+   ((and (equal type ?h)
+         (string-prefix-p "URL:" selector))
+    (elpher-address-from-url (elt (split-string selector "URL:") 1)))
+   ((equal type ?8)
+    (elpher-address-from-url
+     (concat "telnet"
+             "://" host
+             ":" (number-to-string port))))
+   (t

     (elpher-address-from-url
      (concat "gopher" (if tls "s" "")
              "://" host
              ":" (number-to-string port)
              "/" (string type)
     (elpher-address-from-url
      (concat "gopher" (if tls "s" "")
              "://" host
              ":" (number-to-string port)
              "/" (string type)

-             selector))))
+             selector)))))

 
 (defun elpher-make-special-address (type)
   "Create an ADDRESS object corresponding to the given special page symbol TYPE."
 
 (defun elpher-make-special-address (type)
   "Create an ADDRESS object corresponding to the given special page symbol TYPE."


@@ -234,7 +247,9 @@ requiring gopher-over-TLS."
     nil))
 
 (defun elpher-address-type (address)
     nil))
 
 (defun elpher-address-type (address)

-  "Retrieve selector type from ADDRESS object."
+  "Retrieve type of ADDRESS object.
+This is used to determine how to retrieve and render the document the
+address refers to, via the table `elpher-type-map'."

   (if (symbolp address)
       (list 'special address)
     (let ((protocol (url-type address)))
   (if (symbolp address)
       (list 'special address)
     (let ((protocol (url-type address)))


@@ -246,6 +261,8 @@ requiring gopher-over-TLS."
                      (string-to-char (substring (url-filename address) 1)))))
             ((equal protocol "gemini")
              'gemini)
                      (string-to-char (substring (url-filename address) 1)))))
             ((equal protocol "gemini")
              'gemini)

+            ((equal protocol "telnet")
+             'telnet)

             (t 'other-url)))))
 
 (defun elpher-address-protocol (address)
             (t 'other-url)))))
 
 (defun elpher-address-protocol (address)


@@ -266,8 +283,11 @@ For gopher addresses this is a combination of the selector type and selector."
   (url-host address))
 
 (defun elpher-address-port (address)
   (url-host address))
 
 (defun elpher-address-port (address)

-  "Retrieve port from ADDRESS object."
-  (url-port address))
+  "Retrieve port from ADDRESS object.
+If no address is defined, returns 0.  (This is for compatibility with the URL library.)"
+  (if (symbolp address)
+      0
+    (url-port address)))

 
 (defun elpher-address-special-p (address)
   "Return non-nil if ADDRESS object is special (e.g. start page, bookmarks page)."
 
 (defun elpher-address-special-p (address)
   "Return non-nil if ADDRESS object is special (e.g. start page, bookmarks page)."


@@ -400,7 +420,16 @@ unless PRESERVE-PARENT is non-nil."
 (defun elpher-update-header ()
   "If `elpher-use-header' is true, display current node info in window header."
   (if elpher-use-header
 (defun elpher-update-header ()
   "If `elpher-use-header' is true, display current node info in window header."
   (if elpher-use-header

-      (setq header-line-format (elpher-node-display-string elpher-current-node))))
+      (let* ((display-string (elpher-node-display-string elpher-current-node))
+             (address (elpher-node-address elpher-current-node))
+             (tls-string (if (and (not (elpher-address-special-p address))
+                                  (member (elpher-address-protocol address)
+                                          '("gophers" "gemini")))
+                             " [TLS encryption]"
+                           ""))
+             (header (concat display-string
+                             (propertize tls-string 'face 'bold))))
+        (setq header-line-format header))))

 
 (defmacro elpher-with-clean-buffer (&rest args)
   "Evaluate ARGS with a clean *elpher* buffer as current."
 
 (defmacro elpher-with-clean-buffer (&rest args)
   "Evaluate ARGS with a clean *elpher* buffer as current."


@@ -441,7 +470,7 @@ away CRs and any terminating period."
   (elpher-with-clean-buffer
    (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
            "When attempting to retrieve " (elpher-address-to-url address) ":\n"
   (elpher-with-clean-buffer
    (insert (propertize "\n---- ERROR -----\n\n" 'face 'error)
            "When attempting to retrieve " (elpher-address-to-url address) ":\n"

-           (error-message-string error) ".\n"
+           (error-message-string error) "\n"

            (propertize "\n----------------\n\n" 'face 'error)
            "Press 'u' to return to the previous page.")))
 
            (propertize "\n----------------\n\n" 'face 'error)
            "Press 'u' to return to the previous page.")))
 


@@ -476,12 +505,12 @@ up to the calling function."
         (error "Cannot retrieve TLS gopher selector: GnuTLS not available")))
   (condition-case the-error
       (let* ((kill-buffer-query-functions nil)
         (error "Cannot retrieve TLS gopher selector: GnuTLS not available")))
   (condition-case the-error
       (let* ((kill-buffer-query-functions nil)

+             (port (elpher-address-port address))
+             (host (elpher-address-host address))

              (proc (open-network-stream "elpher-process"
                                        nil
              (proc (open-network-stream "elpher-process"
                                        nil

-                                       (elpher-address-host address)
-                                       (if (> (elpher-address-port address) 0)
-                                           (elpher-address-port address)
-                                         70)
+                                       host
+                                       (if (> port 0) port 70)

                                        :type (if elpher-use-tls 'tls 'plain))))
         (set-process-coding-system proc 'binary)
         (set-process-filter proc
                                        :type (if elpher-use-tls 'tls 'plain))))
         (set-process-coding-system proc 'binary)
         (set-process-filter proc


@@ -489,8 +518,9 @@ up to the calling function."
                               (setq elpher-selector-string
                                     (concat elpher-selector-string string))))
         (set-process-sentinel proc after)
                               (setq elpher-selector-string
                                     (concat elpher-selector-string string))))
         (set-process-sentinel proc after)

-        (process-send-string proc
-                             (concat (elpher-gopher-address-selector address) "\n")))
+        (let ((inhibit-eol-conversion t))
+          (process-send-string proc
+                               (concat (elpher-gopher-address-selector address) "\r\n"))))

     (error
      (if (and (consp the-error)
               (eq (car the-error) 'gnutls-error)
     (error
      (if (and (consp the-error)
               (eq (car the-error) 'gnutls-error)


@@ -564,7 +594,9 @@ once they are retrieved from the gopher server."
 (defun elpher-node-button-help (node)
   "Return a string containing the help text for a button corresponding to NODE."
   (let ((address (elpher-node-address node)))
 (defun elpher-node-button-help (node)
   "Return a string containing the help text for a button corresponding to NODE."
   (let ((address (elpher-node-address node)))

-    (format "mouse-1, RET: open '%s'" (elpher-address-to-url address))))
+    (format "mouse-1, RET: open '%s'" (if (elpher-address-special-p address)
+                                          address
+                                        (elpher-address-to-url address)))))

 
 (defun elpher-insert-index-record (display-string &optional address)
   "Function to insert an index record into the current buffer.
 
 (defun elpher-insert-index-record (display-string &optional address)
   "Function to insert an index record into the current buffer.


@@ -587,11 +619,11 @@ If ADDRESS is not supplied or nil the record is rendered as an
       (pcase type
         ((or '(gopher ?i) 'nil) ;; Information
          (elpher-insert-margin)
       (pcase type
         ((or '(gopher ?i) 'nil) ;; Information
          (elpher-insert-margin)

-         (insert (propertize
-                  (if elpher-buttonify-urls-in-directories
-                      (elpher-buttonify-urls display-string)
-                    display-string)
-                  'face 'elpher-info)))
+         (let ((propertized-display-string
+                (propertize display-string 'face 'elpher-info)))
+           (insert (if elpher-buttonify-urls-in-directories
+                       (elpher-buttonify-urls propertized-display-string)
+                     propertized-display-string))))

         (`(gopher ,selector-type) ;; Unknown
          (elpher-insert-margin (concat (char-to-string selector-type) "?"))
          (insert (propertize display-string
         (`(gopher ,selector-type) ;; Unknown
          (elpher-insert-margin (concat (char-to-string selector-type) "?"))
          (insert (propertize display-string


@@ -604,7 +636,7 @@ If ADDRESS is not supplied or nil the record is rendered as an
     (elpher-visit-node node)))
 
 (defun elpher-render-index (data &optional _mime-type-string)
     (elpher-visit-node node)))
 
 (defun elpher-render-index (data &optional _mime-type-string)

-  "Render DATA as an index."
+  "Render DATA as an index.  MIME-TYPE-STRING is unused."

   (elpher-with-clean-buffer
    (if (not data)
        t
   (elpher-with-clean-buffer
    (if (not data)
        t


@@ -615,7 +647,7 @@ 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.\-]+\\|\[[a-zA-Z0-9:]+\]\\)\\(?3::[0-9]+\\)?\\(?4:/[^<> \r\n\t(),]*\\)?"
+  "\\([a-zA-Z]+\\)://\\([a-zA-Z0-9.\-]*[a-zA-Z0-9\-]\\|\[[a-zA-Z0-9:]+\]\\)\\(:[0-9]+\\)?\\(/\\([0-9a-zA-Z\-_~?/@|:.]*[0-9a-zA-Z\-_~?/@|]\\)?\\)?"

   "Regexp used to locate and buttniofy URLs in text files loaded by elpher.")
 
 (defun elpher-buttonify-urls (string)
   "Regexp used to locate and buttniofy URLs in text files loaded by elpher.")
 
 (defun elpher-buttonify-urls (string)


@@ -624,18 +656,19 @@ If ADDRESS is not supplied or nil the record is rendered as an
     (insert string)
     (goto-char (point-min))
     (while (re-search-forward elpher-url-regex nil t)
     (insert string)
     (goto-char (point-min))
     (while (re-search-forward elpher-url-regex nil t)

-      (let ((node (elpher-make-node (match-string 0)
+      (let ((node (elpher-make-node (substring-no-properties (match-string 0))

                                     (elpher-address-from-url (match-string 0)))))
           (make-text-button (match-beginning 0)
                             (match-end 0)
                             'elpher-node  node
                             'action #'elpher-click-link
                             'follow-link t
                                     (elpher-address-from-url (match-string 0)))))
           (make-text-button (match-beginning 0)
                             (match-end 0)
                             'elpher-node  node
                             'action #'elpher-click-link
                             'follow-link t

-                            'help-echo (elpher-node-button-help node))))
+                            'help-echo (elpher-node-button-help node)
+                            'face 'button)))

     (buffer-string)))
 
 (defun elpher-render-text (data &optional _mime-type-string)
     (buffer-string)))
 
 (defun elpher-render-text (data &optional _mime-type-string)

-  "Render DATA as text."
+  "Render DATA as text.  MIME-TYPE-STRING is unused."

   (elpher-with-clean-buffer
    (if (not data)
        t
   (elpher-with-clean-buffer
    (if (not data)
        t


@@ -647,7 +680,7 @@ If ADDRESS is not supplied or nil the record is rendered as an
 ;; Image retrieval
 
 (defun elpher-render-image (data &optional _mime-type-string)
 ;; Image retrieval
 
 (defun elpher-render-image (data &optional _mime-type-string)

-  "Display DATA as image."
+  "Display DATA as image.  MIME-TYPE-STRING is unused."

   (if (not data)
       nil
     (if (display-images-p)
   (if (not data)
       nil
     (if (display-images-p)


@@ -696,7 +729,7 @@ The response is rendered using the rendering function RENDERER."
 ;; 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)

-  "Display raw DATA in buffer."
+  "Display raw DATA in buffer.  MIME-TYPE-STRING is unused."

   (if (not data)
       nil
     (elpher-with-clean-buffer
   (if (not data)
       nil
     (elpher-with-clean-buffer


@@ -707,7 +740,7 @@ The response is rendered using the rendering function RENDERER."
 ;; File save "rendering"
 
 (defun elpher-render-download (data &optional _mime-type-string)
 ;; File save "rendering"
 
 (defun elpher-render-download (data &optional _mime-type-string)

-  "Save DATA to file."
+  "Save DATA to file.  MIME-TYPE-STRING is unused."

   (if (not data)
       nil
     (let* ((address (elpher-node-address elpher-current-node))
   (if (not data)
       nil
     (let* ((address (elpher-node-address elpher-current-node))


@@ -727,7 +760,7 @@ The response is rendered using the rendering function RENDERER."
 ;; HTML rendering
 
 (defun elpher-render-html (data &optional _mime-type-string)
 ;; HTML rendering
 
 (defun elpher-render-html (data &optional _mime-type-string)

-  "Render DATA as HTML using shr."
+  "Render DATA as HTML using shr.  MIME-TYPE-STRING is unused."

   (elpher-with-clean-buffer
    (if (not data)
        t
   (elpher-with-clean-buffer
    (if (not data)
        t


@@ -739,76 +772,108 @@ The response is rendered using the rendering function RENDERER."
 ;; Gemini node retrieval
 
 (defvar elpher-gemini-response)
 ;; Gemini node retrieval
 
 (defvar elpher-gemini-response)

+(defvar elpher-gemini-redirect-chain)

 
 (defun elpher-get-gemini-response (address after)
   "Retrieve gemini ADDRESS, then execute AFTER.
 The response is stored in the variable ‘elpher-gemini-response’."
   (setq elpher-gemini-response "")
   (if (not (gnutls-available-p))
 
 (defun elpher-get-gemini-response (address after)
   "Retrieve gemini ADDRESS, then execute AFTER.
 The response is stored in the variable ‘elpher-gemini-response’."
   (setq elpher-gemini-response "")
   (if (not (gnutls-available-p))

-      (error "Cannot retrieve TLS selector: GnuTLS not available")
-    (let* ((kill-buffer-query-functions nil)
-           (proc (open-network-stream "elpher-process"
-                                      nil
-                                      (elpher-address-host address)
-                                      (if (> (elpher-address-port address) 0)
-                                          (elpher-address-port address)
-                                        1965)
-                                      :type 'tls)))
-      (set-process-coding-system proc 'binary)
-      (set-process-filter proc
-                          (lambda (_proc string)
-                            (setq elpher-gemini-response
-                                  (concat elpher-gemini-response string))))
-      (set-process-sentinel proc after)
-      (process-send-string proc
-                           (concat (elpher-address-to-url address) "\r\n")))))
+      (error "Cannot establish gemini connection: GnuTLS not available")
+    (condition-case the-error
+        (let* ((kill-buffer-query-functions nil)
+               (network-security-level 'medium)
+               (port (elpher-address-port address))
+               (host (elpher-address-host address))
+               (proc (open-network-stream "elpher-process"
+                                          nil
+                                          host
+                                          (if (> port 0) port 1965)
+                                          :type 'tls
+                                          :nowait t)))
+          (set-process-coding-system proc 'binary)
+          (set-process-filter proc
+                              (lambda (_proc string)
+                                (setq elpher-gemini-response
+                                      (concat elpher-gemini-response string))))
+          (set-process-sentinel proc after)
+          (let ((inhibit-eol-conversion t))
+            (process-send-string proc
+                                 (concat (elpher-address-to-url address) "\r\n"))))
+      (error
+       (error "Error initiating connection to server")))))
+
+(defun elpher-parse-gemini-response (response)
+  "Parse the RESPONSE string and return a list of components
+The list is of the form (code meta body). A response of nil implies
+that the response was malformed."
+  (let ((header-end-idx (string-match "\r\n" response)))
+    (if header-end-idx
+        (let ((header (string-trim (substring response 0 header-end-idx)))
+              (body (substring response (+ header-end-idx 2))))
+          (if (>= (length header) 2)
+              (let ((code (substring header 0 2))
+                    (meta (string-trim (substring header 2))))
+                (list code meta body))
+            (error "Malformed response: No response status found in header %s" header)))
+      (error "Malformed response: No CRLF-delimited header found"))))

 
 
 (defun elpher-process-gemini-response (renderer)
   "Process the gemini response and pass the result to RENDERER.
 The response is assumed to be in the variable `elpher-gemini-response'."
   (condition-case the-error
 
 
 (defun elpher-process-gemini-response (renderer)
   "Process the gemini response and pass the result to RENDERER.
 The response is assumed to be in the variable `elpher-gemini-response'."
   (condition-case the-error

-      (let* ((response-header (car (split-string elpher-gemini-response "\r\n")))
-             (response-body (substring elpher-gemini-response
-                                       (+ (string-match "\r\n" elpher-gemini-response) 2)))
-             (response-code (car (split-string response-header)))
-             (response-meta (string-trim
-                             (substring response-header
-                                        (string-match "[ \t]+" response-header)))))
-        (pcase (elt response-code 0)
-          (?1 ; Input required
-           (elpher-with-clean-buffer
-            (insert "Gemini server is requesting input."))
-           (let* ((query-string (read-string (concat response-meta ": ")))
-                  (url (elpher-address-to-url (elpher-node-address elpher-current-node)))
-                  (query-address (elpher-address-from-url (concat url "?" query-string))))
-             (elpher-get-gemini-response query-address
-                                         (lambda (_proc event)
-                                           (unless (string-prefix-p "deleted" event)
-                                             (funcall #'elpher-process-gemini-response
-                                                      renderer)
-                                             (elpher-restore-pos))))))
-          (?2 ; Normal response
-           ;; (message response-header)
-           (funcall renderer response-body response-meta))
-          (?3 ; Redirect
-           (message "Following redirect to %s" response-meta)
-           (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
-             (elpher-get-gemini-response redirect-address
-                                         (lambda (_proc event)
-                                           (unless (string-prefix-p "deleted" event)
-                                             (funcall #'elpher-process-gemini-response
-                                                      renderer)
-                                             (elpher-restore-pos))))))
-          (?4 ; Temporary failure
-           (error "Gemini server reports TEMPORARY FAILURE for this request"))
-          (?5 ; Permanent failure
-           (error "Gemini server reports PERMANENT FAILURE for this request"))
-          (?6 ; Client certificate required
-           (error "Gemini server requires client certificate (unsupported at this time)"))
-          (_other
-           (error "Gemini server responded with unknown response code %S"
-                  response-code))))
+      (let ((response-components (elpher-parse-gemini-response elpher-gemini-response)))
+        (let ((response-code (elt response-components 0))
+              (response-meta (elt response-components 1))
+              (response-body (elt response-components 2)))
+          (pcase (elt response-code 0)
+            (?1 ; Input required
+             (elpher-with-clean-buffer
+              (insert "Gemini server is requesting input."))
+             (let* ((query-string (read-string (concat response-meta ": ")))
+                    (url (elpher-address-to-url (elpher-node-address elpher-current-node)))
+                    (query-address (elpher-address-from-url (concat url "?" query-string))))
+               (elpher-get-gemini-response query-address
+                                           (lambda (_proc event)
+                                             (unless (or (string-prefix-p "deleted" event)
+                                                         (string-prefix-p "open" event))
+                                               (funcall #'elpher-process-gemini-response
+                                                        renderer)
+                                               (elpher-restore-pos))))))
+            (?2 ; Normal response
+             ;; (message response-header)
+             (funcall renderer response-body response-meta))
+            (?3 ; Redirect
+             (message "Following redirect to %s" response-meta)
+             (if (>= (length elpher-gemini-redirect-chain) 5)
+                 (error "More than 5 consecutive redirects followed"))
+             (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
+               (if (member redirect-address elpher-gemini-redirect-chain)
+                   (error "Redirect loop detected"))
+               (if (not (string= (elpher-address-protocol redirect-address)
+                                 "gemini"))
+                   (error "Server tried to automatically redirect to non-gemini URL: %s"
+                          response-meta))
+               (add-to-list 'elpher-gemini-redirect-chain redirect-address)
+               (elpher-get-gemini-response redirect-address
+                                           (lambda (_proc event)
+                                             (unless (or (string-prefix-p "deleted" event)
+                                                         (string-prefix-p "open" event))
+                                               (funcall #'elpher-process-gemini-response
+                                                        renderer)
+                                               (elpher-restore-pos))))))
+            (?4 ; Temporary failure
+             (error "Gemini server reports TEMPORARY FAILURE for this request: %s %s"
+                    response-code response-meta))
+            (?5 ; Permanent failure
+             (error "Gemini server reports PERMANENT FAILURE for this request: %s %s"
+                    response-code response-meta))
+            (?6 ; Client certificate required
+             (error "Gemini server requires client certificate (unsupported at this time)"))
+            (_other
+             (error "Gemini server response unknown: %s %s"
+                    response-code response-meta)))))

     (error
      (elpher-network-error (elpher-node-address elpher-current-node) the-error))))
 
     (error
      (elpher-network-error (elpher-node-address elpher-current-node) the-error))))
 


@@ -823,9 +888,11 @@ The response is assumed to be in the variable `elpher-gemini-response'."
               (elpher-restore-pos))
           (elpher-with-clean-buffer
            (insert "LOADING GEMINI... (use 'u' to cancel)"))
               (elpher-restore-pos))
           (elpher-with-clean-buffer
            (insert "LOADING GEMINI... (use 'u' to cancel)"))

+          (setq elpher-gemini-redirect-chain nil)

           (elpher-get-gemini-response address
                                       (lambda (_proc event)
           (elpher-get-gemini-response address
                                       (lambda (_proc event)

-                                        (unless (string-prefix-p "deleted" event)
+                                        (unless (or (string-prefix-p "deleted" event)
+                                                    (string-prefix-p "open" event))

                                           (funcall #'elpher-process-gemini-response
                                                    renderer)
                                           (elpher-restore-pos)))))
                                           (funcall #'elpher-process-gemini-response
                                                    renderer)
                                           (elpher-restore-pos)))))


@@ -848,13 +915,12 @@ The response is assumed to be in the variable `elpher-gemini-response'."
                                    (list (downcase (string-trim (car key-val)))
                                          (downcase (string-trim (cadr key-val))))))
                                (cdr mime-type-split))))
                                    (list (downcase (string-trim (car key-val)))
                                          (downcase (string-trim (cadr key-val))))))
                                (cdr mime-type-split))))

-      (if (and (equal "text/gemini" mime-type)
-               (not (assoc "charset" parameters)))
-          (setq parameters (cons (list "charset" "utf-8") parameters)))

       (when (string-prefix-p "text/" mime-type)
       (when (string-prefix-p "text/" mime-type)

-        (if (assoc "charset" parameters)
-            (setq body (decode-coding-string body
-                                             (intern (cadr (assoc "charset" parameters))))))
+        (setq body (decode-coding-string
+                    body
+                    (if (assoc "charset" parameters)
+                        (intern (cadr (assoc "charset" parameters)))
+                      'utf-8)))

         (setq body (replace-regexp-in-string "\r" "" body)))
       (pcase mime-type
         ((or "text/gemini" "")
         (setq body (replace-regexp-in-string "\r" "" body)))
       (pcase mime-type
         ((or "text/gemini" "")


@@ -878,12 +944,25 @@ The response is assumed to be in the variable `elpher-gemini-response'."
         (string-trim (substring rest (+ idx 1)))
       "")))
 
         (string-trim (substring rest (+ idx 1)))
       "")))
 

+(defun elpher-collapse-dot-sequences (filename)
+  "Collapse dot sequences in FILENAME.
+For instance, the filename /a/b/../c/./d will reduce to /a/c/d"
+  (let* ((path (split-string filename "/"))
+         (path-reversed-normalized
+          (seq-reduce (lambda (a b)
+                        (cond ((and a (equal b "..") (cdr a)))
+                              ((and (not a) (equal b "..")) a) ;leading .. are dropped
+                              ((equal b ".") a)
+                              (t (cons b a))))
+                      path nil)))
+    (string-join (reverse path-reversed-normalized) "/")))
+

 (defun elpher-address-from-gemini-url (url)
   "Extract address from URL with defaults as per gemini map files."
   (let ((address (url-generic-parse-url url)))
     (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
       (setf (url-fullness address) t)
 (defun elpher-address-from-gemini-url (url)
   "Extract address from URL with defaults as per gemini map files."
   (let ((address (url-generic-parse-url url)))
     (unless (and (url-type address) (not (url-fullness address))) ;avoid mangling mailto: urls
       (setf (url-fullness address) t)

-      (unless (url-host address) ;if there is an explicit host, filenames are explicit
+      (unless (url-host address) ;if there is an explicit host, filenames are absolute

         (setf (url-host address) (url-host (elpher-node-address elpher-current-node)))
         (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
           (setf (url-filename address)
         (setf (url-host address) (url-host (elpher-node-address elpher-current-node)))
         (unless (string-prefix-p "/" (url-filename address)) ;deal with relative links
           (setf (url-filename address)


@@ -891,7 +970,10 @@ The response is assumed to be in the variable `elpher-gemini-response'."
                          (url-filename (elpher-node-address elpher-current-node)))
                         (url-filename address)))))
       (unless (url-type address)
                          (url-filename (elpher-node-address elpher-current-node)))
                         (url-filename address)))))
       (unless (url-type address)

-        (setf (url-type address) "gemini")))
+        (setf (url-type address) "gemini"))
+      (if (equal (url-type address) "gemini")
+          (setf (url-filename address)
+                (elpher-collapse-dot-sequences (url-filename address)))))

     address))
 
 (defun elpher-render-gemini-map (data _parameters)
     address))
 
 (defun elpher-render-gemini-map (data _parameters)


@@ -911,7 +993,7 @@ The response is assumed to be in the variable `elpher-gemini-response'."
     (buffer-string))))
 
 (defun elpher-render-gemini-plain-text (data _parameters)
     (buffer-string))))
 
 (defun elpher-render-gemini-plain-text (data _parameters)

-  "Render DATA as plain text file."
+  "Render DATA as plain text file.  PARAMETERS is currently unused."

   (elpher-with-clean-buffer
    (insert (elpher-buttonify-urls data))
    (elpher-cache-content
   (elpher-with-clean-buffer
    (insert (elpher-buttonify-urls data))
    (elpher-cache-content


@@ -945,7 +1027,9 @@ The response is assumed to be in the variable `elpher-gemini-response'."
          (host (elpher-address-host address))
          (port (elpher-address-port address)))
     (elpher-visit-parent-node)
          (host (elpher-address-host address))
          (port (elpher-address-port address)))
     (elpher-visit-parent-node)

-    (telnet host port)))
+    (if (> port 0)
+        (telnet host port)
+      (telnet host))))

 
 ;; Start page node retrieval
 
 
 ;; Start page node retrieval
 


@@ -965,7 +1049,7 @@ The response is assumed to be in the variable `elpher-gemini-response'."
            " - 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"
            " - TAB/Shift-TAB: next/prev item on current page\n"
            " - RET/mouse-1: open item under cursor\n"
            " - m: select an item on current page by name (autocompletes)\n"

-           " - u: return to previous page\n"
+           " - u/mouse-3: return to previous page\n"

            " - o/O: visit different selector or the root menu of the current server\n"
            " - g: go to a particular gopher address\n"
            " - d/D: download item under cursor or current page\n"
            " - o/O: visit different selector or the root menu of the current server\n"
            " - g: go to a particular gopher address\n"
            " - d/D: download item under cursor or current page\n"


@@ -987,6 +1071,9 @@ The response is assumed to be in the variable `elpher-gemini-response'."
            "Alternatively, select the following item and enter some search terms:\n")
    (elpher-insert-index-record "Veronica-2 Gopher Search Engine"
                                (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))
            "Alternatively, select the following item and enter some search terms:\n")
    (elpher-insert-index-record "Veronica-2 Gopher Search Engine"
                                (elpher-make-gopher-address ?7 "/v2/vs" "gopher.floodgap.com" 70))

+   (insert "\n"
+           "This page contains your bookmarked sites (also visit with B):\n")
+   (elpher-insert-index-record "Your Bookmarks" 'bookmarks)

    (insert "\n"
            "** Refer to the ")
    (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))
    (insert "\n"
            "** Refer to the ")
    (let ((help-string "RET,mouse-1: Open Elpher info manual (if available)"))


@@ -1150,7 +1237,7 @@ If ADDRESS is already bookmarked, update the label only."
     (message "No current site.")))
 
 (defun elpher-toggle-tls ()
     (message "No current site.")))
 
 (defun elpher-toggle-tls ()

-  "Toggle TLS encryption mode."
+  "Toggle TLS encryption mode for gopher."

   (interactive)
   (setq elpher-use-tls (not elpher-use-tls))
   (if elpher-use-tls
   (interactive)
   (setq elpher-use-tls (not elpher-use-tls))
   (if elpher-use-tls


@@ -1313,7 +1400,7 @@ If ADDRESS is already bookmarked, update the label only."
         (address (elpher-node-address node)))
     (if (elpher-address-special-p address)
         (message "Special page: %s" display-string)
         (address (elpher-node-address node)))
     (if (elpher-address-special-p address)
         (message "Special page: %s" display-string)

-      (message (elpher-address-to-url address)))))
+      (message "%s" (elpher-address-to-url address)))))

 
 (defun elpher-info-link ()
   "Display information on node corresponding to link at point."
 
 (defun elpher-info-link ()
   "Display information on node corresponding to link at point."


@@ -1368,6 +1455,7 @@ If ADDRESS is already bookmarked, update the label only."
     (define-key map (kbd "TAB") 'elpher-next-link)
     (define-key map (kbd "<backtab>") 'elpher-prev-link)
     (define-key map (kbd "u") 'elpher-back)
     (define-key map (kbd "TAB") 'elpher-next-link)
     (define-key map (kbd "<backtab>") 'elpher-prev-link)
     (define-key map (kbd "u") 'elpher-back)

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

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


@@ -1394,6 +1482,7 @@ If ADDRESS is already bookmarked, update the label only."
         (kbd "C-") 'elpher-follow-current-link
         (kbd "C-t") 'elpher-back
         (kbd "u") 'elpher-back
         (kbd "C-") 'elpher-follow-current-link
         (kbd "C-t") 'elpher-back
         (kbd "u") 'elpher-back

+        [mouse-3] 'elpher-back

         (kbd "g") 'elpher-go
         (kbd "o") 'elpher-go-current
         (kbd "r") 'elpher-redraw
         (kbd "g") 'elpher-go
         (kbd "o") 'elpher-go-current
         (kbd "r") 'elpher-redraw


@@ -1417,7 +1506,7 @@ If ADDRESS is already bookmarked, update the label only."
   "Keymap for gopher client.")
 
 (define-derived-mode elpher-mode special-mode "elpher"
   "Keymap for gopher client.")
 
 (define-derived-mode elpher-mode special-mode "elpher"

-  "Major mode for elpher, an elisp gopher client.)))))))
+  "Major mode for elpher, an elisp gopher client.

 
 This mode is automatically enabled by the interactive
 functions which initialize the gopher client, namely
 
 This mode is automatically enabled by the interactive
 functions which initialize the gopher client, namely