+;; Gemini node retrieval
+
+(defvar elpher-gemini-response)
+(defvar elpher-gemini-response-header)
+(defvar elpher-gemini-in-header)
+
+(defun elpher-gemini-response-code ()
+ (elt (split-string elpher-gemini-response-header) 0))
+
+(defun elpher-gemini-response-meta ()
+ (string-trim (substring elpher-gemini-response-header
+ (string-match "[ \t]+" elpher-gemini-response-header))))
+
+(defun elpher-get-gemini (address after)
+ "Retrieve gemini ADDRESS, then execute AFTER.
+The response header is stored in the variable ‘elpher-gemini-response-header’.
+If available, the response is stored in the variable ‘elpher-gemini-response’.
+
+Usually errors result in an error page being displayed. This is only
+appropriate if the selector is to be directly viewed. If PROPAGATE-ERROR
+is non-nil, this message is not displayed. Instead, the error propagates
+up to the calling function."
+ (setq elpher-gemini-response "")
+ (setq elpher-gemini-response-header "")
+ (setq elpher-gemini-in-header t)
+ (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)
+ (elpher-address-port address)
+ :type 'tls)))
+ (set-process-coding-system proc 'binary)
+ (set-process-filter proc
+ (lambda (proc string)
+ (if elpher-gemini-in-header
+ (progn
+ (setq elpher-gemini-response-header
+ (concat elpher-gemini-response-header
+ (elt (split-string string "\r\n") 0)))
+ (let ((idx (string-match "\r\n" string)))
+ (setq elpher-gemini-response
+ (substring string (+ idx 2)))
+ (setq elpher-gemini-in-header nil)))
+ (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")))))
+
+(defun elpher-render-gemini-response (mime-type-raw)
+ (let* ((mime-type-full (if (string-empty-p mime-type-raw)
+ "text/gemini; charset=utf-8"
+ mime-type-raw))
+ (mime-type-split (split-string mime-type-full ";"))
+ (mime-type (string-trim (elt mime-type-split 0)))
+ (parameters (if (> (length mime-type-split) 1)
+ (string-trim (elt mime-type-split 1))
+ "")))
+ (message "MIME type %S" mime-type)
+ (pcase mime-type
+ ((or "text/gemini" "")
+ (elpher-render--mimetype-text/gemini elpher-gemini-response parameters))
+ ((pred (string-prefix-p "text/"))
+ (elpher-render--mimetype-text/plain elpher-gemini-response parameters))
+ ((pred (string-prefix-p "image/"))
+ (elpher-render--mimetype-image/* elpher-gemini-response parameters))
+ (other
+ (error "Unsupported MIME type %S" mime-type)))))
+
+(defun elpher-gemini-get-link-url (line)
+ (string-trim (elt (split-string (substring line 2)) 0)))
+
+(defun elpher-gemini-get-link-display-string (line)
+ (let* ((rest (string-trim (elt (split-string line "=>") 1)))
+ (idx (string-match "[ \t]" rest)))
+ (if idx
+ (string-trim (substring rest (+ idx 1)))
+ "")))
+
+(defun elpher-address-from-gemini-url (url)
+ (let ((address (url-generic-parse-url url)))
+ (setf (url-fullness address) t)
+ (unless (url-host address)
+ (setf (url-host address) (url-host (elpher-node-address elpher-current-node)))
+ (unless (string-prefix-p "/" (url-filename address))
+ (setf (url-filename address)
+ (concat (file-name-as-directory
+ (url-filename (elpher-node-address elpher-current-node)))
+ (url-filename address)))))
+ (unless (url-type address)
+ (setf (url-type address) "gemini"))
+ (unless (> (url-port address) 0)
+ (pcase (url-type address)
+ ("gemini" (setf (url-port address) 1965))
+ ("gopher" (setf (url-port address) 70))))
+ address))
+
+(defun elpher-render--mimetype-text/gemini (data parameters)
+ (elpher-with-clean-buffer
+ (dolist (line (split-string (elpher-preprocess-text-response 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)))
+ (insert (elpher-buttonify-urls line) "\n")))
+ (elpher-restore-pos)
+ (elpher-cache-content
+ (elpher-node-address elpher-current-node)
+ (buffer-string))))
+
+(defun elpher-render--mimetype-text/plain (data parameters)
+ (elpher-with-clean-buffer
+ (insert (elpher-buttonify-urls (elpher-preprocess-text-response data)))
+ (elpher-restore-pos)
+ (elpher-cache-content
+ (elpher-node-address elpher-current-node)
+ (buffer-string))))
+
+(defun elpher-render--mimetype-image/* (data parameters)
+ (let ((image (create-image data nil t)))
+ (elpher-with-clean-buffer
+ (insert-image image)
+ (elpher-restore-pos))))
+
+(defun elpher-process-gemini-response (proc event)
+ (condition-case the-error
+ (unless (string-prefix-p "deleted" event)
+ (let ((response-code (elpher-gemini-response-code))
+ (meta (elpher-gemini-response-meta)))
+ (pcase (elt response-code 0)
+ (?1 ; Input required
+ (elpher-with-clean-buffer
+ (insert "Gemini server is requesting input."))
+ (let* ((query-string (read-string (concat 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 query-address #'elpher-process-gemini-response)))
+ (?2 ; Normal response
+ (elpher-render-gemini-response meta))
+ (?3 ; Redirect
+ (message "Following redirect to %s" meta)
+ (let ((redirect-address (elpher-address-from-gemini-url meta)))
+ (elpher-get-gemini redirect-address #'elpher-process-gemini-response)))
+ (?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)))))
+ (error
+ (elpher-network-error (elpher-node-address elpher-current-node) the-error))))
+
+
+(defun elpher-get-gemini-node ()
+ "Getter which retrieves and renders a Gemini node."
+ (let* ((address (elpher-node-address elpher-current-node))
+ (content (elpher-get-cached-content address)))
+ (condition-case the-error
+ (if content
+ (progn
+ (elpher-with-clean-buffer
+ (insert content)
+ (elpher-restore-pos)))
+ (elpher-with-clean-buffer
+ (insert "LOADING GEMINI... (use 'u' to cancel)"))
+ (elpher-get-gemini address #'elpher-process-gemini-response))
+ (error
+ (elpher-network-error address the-error)))))
+
+
+
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