Abort connection handshake when connection timeout is reached (#84)

Author: Namoshek

src/MqttClient.php

@@ -315,6 +315,8 @@ private function parseTlsErrorMessage(?array $phpError, ?string &$tlsErrorCode =
     protected function performConnectionHandshake(bool $useCleanSession = false): void
     {
         try {
+            $connectionHandshakeStartedAt = microtime(true);
+
             $data = $this->messageProcessor->buildConnectMessage($this->settings, $useCleanSession);
 
             $this->logger->debug('Sending connection handshake to broker.');
@@ -349,6 +351,15 @@ protected function performConnectionHandshake(bool $useCleanSession = false): vo
 
                     break;
                 }
+
+                // If no acknowledgement has been received from the broker within the configured connection timeout period,
+                // we abort the connection attempt and assume broker unavailability.
+                if (microtime(true) - $this->settings->getConnectTimeout() > $connectionHandshakeStartedAt) {
+                    throw new ConnectingToBrokerFailedException(
+                        ConnectingToBrokerFailedException::EXCEPTION_CONNECTION_BROKER_UNAVAILABLE,
+                        'The broker did not acknowledge the connection attempt within the configured connection timeout period.'
+                    );
+                }
             }
 
             // We need to set the global buffer to the remaining data we might already have read.