From b12d920d7a38d13fa515449b1d1735616bce5847 Mon Sep 17 00:00:00 2001 From: Tim Vaughan Date: Thu, 31 Oct 2019 10:47:54 +0100 Subject: [PATCH] Improved error handling, cancels unused timers. --- elpher.el | 197 ++++++++++++++++++++++++++++-------------------------- 1 file changed, 102 insertions(+), 95 deletions(-) diff --git a/elpher.el b/elpher.el index 0466a45..a17c403 100644 --- a/elpher.el +++ b/elpher.el @@ -469,11 +469,12 @@ away CRs and any terminating period." ;; (defun elpher-network-error (address error) - "Display ERROR message following unsuccessful negotiation with ADDRESS." + "Display ERROR message following unsuccessful negotiation with ADDRESS. +ERROR can be either an error object or a string." (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" + (if (stringp error) error (error-message-string error)) "\n" (propertize "\n----------------\n\n" 'face 'error) "Press 'u' to return to the previous page."))) @@ -482,29 +483,33 @@ away CRs and any terminating period." ;; (defun elpher-process-cleanup () - "Immediately shut down any extant elpher process." + "Immediately shut down any extant elpher process and timers." (let ((p (get-process "elpher-process"))) - (if p (delete-process p)))) + (if p (delete-process p))) + (if (timerp elpher-network-timer) + (cancel-timer elpher-network-timer))) (defvar elpher-use-tls nil "If non-nil, use TLS to communicate with gopher servers.") -(defvar elpher-selector-string) +(defvar elpher-network-timer) (defun elpher-get-selector (address renderer &optional force-ipv4) "Retrieve selector specified by ADDRESS, then render it using RENDERER. If FORCE-IPV4 is non-nil, explicitly look up and use IPv4 address corresponding to ADDRESS." - (setq elpher-selector-string "") (when (equal (elpher-address-protocol address) "gophers") (if (gnutls-available-p) (when (not elpher-use-tls) (setq elpher-use-tls t) (message "Engaging TLS gopher mode.")) - (error "Cannot retrieve TLS gopher selector: GnuTLS not available"))) + (elpher-network-error "Cannot retrieve TLS gopher selector: GnuTLS not available"))) + (unless (< (elpher-address-port address) 65536) + (elpher-network-error "Cannot retrieve gopher selector: port number > 65536")) (let* ((kill-buffer-query-functions nil) (port (elpher-address-port address)) (host (elpher-address-host address)) + (selector-string "") (proc (open-network-stream "elpher-process" nil (if force-ipv4 (dns-query host) host) @@ -514,7 +519,6 @@ to ADDRESS." (timer (run-at-time elpher-connection-timeout nil (lambda () - (message "timeout (status %s)" (process-status proc)) (pcase (process-status proc) ('failed (if (and (not (equal (elpher-address-protocol address) @@ -525,38 +529,38 @@ to ADDRESS." (progn (message "Disabling TLS mode.") (setq elpher-use-tls nil) - (elpher-get-selector address renderer)))) + (elpher-get-selector address renderer)) + (elpher-network-error "Could not establish encrypted connection."))) ('connect (elpher-process-cleanup) (unless 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) - (message "filter") (cancel-timer timer) - (setq elpher-selector-string - (concat elpher-selector-string string)))) + (setq selector-string + (concat selector-string string)))) (set-process-sentinel proc (lambda (_proc event) - (message "Event: %s" event) - (cond - ((string-prefix-p "deleted" event)) - ((string-prefix-p "open" event) - (let ((inhibit-eol-conversion t)) - (process-send-string - proc - (concat (elpher-gopher-address-selector address) - "\r\n")))) - (t - (cancel-timer timer) - (condition-case the-error - (progn - (funcall renderer elpher-selector-string) - (elpher-restore-pos)) - (error - (message "sentinel %s" the-error) - (elpher-network-error address the-error))))))))) + (condition-case the-error + (cond + ((string-prefix-p "deleted" event)) + ((string-prefix-p "open" event) + (let ((inhibit-eol-conversion t)) + (process-send-string + proc + (concat (elpher-gopher-address-selector address) + "\r\n")))) + (t + (cancel-timer timer) + (funcall renderer selector-string) + (elpher-restore-pos))) + (error + (elpher-network-error address + (error-message-string the-error)))))))) (defun elpher-get-gopher-node (renderer) "Getter function for gopher nodes. @@ -783,21 +787,22 @@ The response is rendered using the rendering function RENDERER." ;; Gemini node retrieval -(defvar elpher-gemini-response) (defvar elpher-gemini-redirect-chain) (defun elpher-get-gemini-response (address renderer &optional force-ipv4) "Retrieve gemini ADDRESS, then render using RENDERER. If FORCE-IPV4 is non-nil, explicitly look up and use IPv4 address corresponding to ADDRESS." - (setq elpher-gemini-response "") (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")) (condition-case the-error (let* ((kill-buffer-query-functions nil) (network-security-level 'medium) (port (elpher-address-port address)) (host (elpher-address-host address)) + (response-string "") (proc (open-network-stream "elpher-process" nil (if force-ipv4 (dns-query host) host) @@ -809,32 +814,39 @@ to ADDRESS." (elpher-process-cleanup) (unless force-ipv4 ; Try again with IPv4 + (message "Connection timed out. Retrying with IPv4.") (elpher-get-gemini-response 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 elpher-gemini-response - (concat elpher-gemini-response string)))) + (setq response-string + (concat response-string string)))) (set-process-sentinel proc (lambda (proc event) - (cond - ((string-prefix-p "open" event) ; request URL - (let ((inhibit-eol-conversion t)) - (process-send-string - proc - (concat (elpher-address-to-url address) - "\r\n")))) - ((string-prefix-p "deleted" event)) ; do nothing - ((and (string-empty-p elpher-gemini-response) - (not force-ipv4)) + (condition-case the-error + (cond + ((string-prefix-p "open" event) ; request URL + (let ((inhibit-eol-conversion t)) + (process-send-string + proc + (concat (elpher-address-to-url address) + "\r\n")))) + ((string-prefix-p "deleted" event)) ; do nothing + ((and (string-empty-p response-string) + (not force-ipv4)) ; Try again with IPv4 - (cancel-timer timer) - (elpher-get-gemini-response address renderer t)) - (t - (funcall #'elpher-process-gemini-response - renderer) - (elpher-restore-pos)))))) + (message "Connection failed. Retrying with IPv4.") + (cancel-timer timer) + (elpher-get-gemini-response address renderer t)) + (t + (funcall #'elpher-process-gemini-response + response-string + renderer) + (elpher-restore-pos))) + (error the-error + (elpher-network-error address the-error)))))) (error (error "Error initiating connection to server"))))) @@ -853,51 +865,46 @@ that the response was malformed." (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 - (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 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)) - (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))))) - (error - (elpher-network-error (elpher-node-address elpher-current-node) the-error)))) +(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 ": "))) + (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 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)) + (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)))))) (defun elpher-get-gemini-node (renderer) "Getter which retrieves and renders a Gemini node and renders it using RENDERER." -- 2.20.1