-;; Gemini node retrieval
-
-(defvar elpher-gemini-response)
-
-(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")
- (condition-case the-error
- (let* ((kill-buffer-query-functions nil)
- (proc (open-network-stream "elpher-process"
- nil
- (elpher-address-host address)
- (elpher-address-port address)
- :type '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
- (error "Error initiating connection to server")))))
+;; Gemini page retrieval
+
+(defvar elpher-gemini-redirect-chain)
+
+(defun elpher-get-gemini-response (address renderer)
+ (elpher-get-host-response address 1965
+ (concat (elpher-address-to-url address) "\r\n")
+ (lambda (response-string)
+ (elpher-process-gemini-response response-string renderer))
+ 'gemini))
+
+(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 in response %s" response))))
+
+(defun elpher-process-gemini-response (response-string renderer)
+ "Process the gemini response RESPONSE-STRING and pass the result to RENDERER."
+ (let ((response-components (elpher-parse-gemini-response response-string)))
+ (let ((response-code (elt response-components 0))
+ (response-meta (elt response-components 1))
+ (response-body (elt response-components 2)))
+ (pcase (elt response-code 0)
+ (?1 ; Input required
+ (elpher-with-clean-buffer
+ (insert "Gemini server is requesting input."))
+ (let* ((query-string (read-string (concat response-meta ": ")))
+ (query-address (seq-copy (elpher-page-address elpher-current-page)))
+ (old-fname (url-filename query-address)))
+ (setf (url-filename query-address)
+ (concat old-fname "?" (url-build-query-string `((,query-string)))))
+ (elpher-get-gemini-response query-address renderer)))
+ (?2 ; Normal response
+ (funcall renderer response-body response-meta))
+ (?3 ; Redirect
+ (message "Following redirect to %s" response-meta)
+ (if (>= (length elpher-gemini-redirect-chain) 5)
+ (error "More than 5 consecutive redirects followed"))
+ (let ((redirect-address (elpher-address-from-gemini-url response-meta)))
+ (if (member redirect-address elpher-gemini-redirect-chain)
+ (error "Redirect loop detected"))
+ (if (not (string= (elpher-address-protocol redirect-address)
+ "gemini"))
+ (error "Server tried to automatically redirect to non-gemini URL: %s"
+ response-meta))
+ (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
+ (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))))))