Regularly test connection stability of HTTP tunnel.
Unlike the WebSocket tunnel, where a manual ping request/response must
be explicitly implemented, we can rely on HTTP's own request/response
to verify stability.
@@ -258,6 +258,25 @@ Guacamole.HTTPTunnel = function(tunnelURL, crossDomain, extraTunnelHeaders) {
*/
var unstableTimeout = null;
+ /**
+ * The current connection stability test ping interval ID, if any. This
+ * will only be set upon successful connection.
+ *
+ * @private
+ * @type {Number}
+ */
+ var pingInterval = null;
+
+ /**
+ * The number of milliseconds to wait between connection stability test
+ * pings.
+ *
+ * @private
+ * @constant
+ * @type {Number}
+ */
+ var PING_FREQUENCY = 500;
+
/**
* Additional headers to be sent in tunnel requests. This dictionary can be
* populated with key/value header pairs to pass information such as authentication
@@ -327,6 +346,9 @@ Guacamole.HTTPTunnel = function(tunnelURL, crossDomain, extraTunnelHeaders) {
window.clearTimeout(receive_timeout);
window.clearTimeout(unstableTimeout);
+ // Cease connection test pings
+ window.clearInterval(pingInterval);
+
// Ignore if already closed
if (tunnel.state === Guacamole.Tunnel.State.CLOSED)
return;
@@ -413,6 +435,8 @@ Guacamole.HTTPTunnel = function(tunnelURL, crossDomain, extraTunnelHeaders) {
message_xmlhttprequest.onreadystatechange = function() {
if (message_xmlhttprequest.readyState === 4) {
+ reset_timeout();
+
// If an error occurs during send, handle it
if (message_xmlhttprequest.status !== 200)
handleHTTPTunnelError(message_xmlhttprequest);
@@ -687,6 +711,11 @@ Guacamole.HTTPTunnel = function(tunnelURL, crossDomain, extraTunnelHeaders) {
// Mark as open
tunnel.setState(Guacamole.Tunnel.State.OPEN);
+ // Ping tunnel endpoint regularly to test connection stability
+ pingInterval = setInterval(function sendPing() {
+ tunnel.sendMessage("nop");
+ }, PING_FREQUENCY);
+
// Start reading data
handleResponse(makeRequest());
