Reset the last ping time only after a ping is sent, rather than after… (#5)

* Reset the last ping time only after a ping is sent, rather than after any broker command is received. If broker messages are received too frequently, it causes pings to be never sent and the broker disconnecting the client.

* Reset ping timer when data is sent to the broker

Co-authored-by: Brad Greco <[email protected]>
Co-authored-by: Namoshek <[email protected]>

Author: 3 people

src/MQTTClient.php

@@ -244,7 +244,6 @@ protected function performConnectionHandshake(string $username = null, string $p
                 switch ($acknowledgement[3]) {
                     case chr(0):
                         $this->logger->info(sprintf('Connection with MQTT broker at [%s:%s] established successfully.', $this->host, $this->port));
-                        $this->lastPingAt = microtime(true);
                         break;
                     case chr(1):
                         $this->logger->error(sprintf('The MQTT broker at [%s:%s] does not support MQTT v3.', $this->host, $this->port));
@@ -653,8 +652,6 @@ public function loop(bool $allowSleep = true, bool $exitWhenQueuesEmpty = false,
                             $this->logger->debug(sprintf('Received message with unsupported command [%s]. Skipping.', $command));
                             break;
                     }
-
-                    $this->lastPingAt = microtime(true);
                 } else {
                     $this->logger->error('A reserved command has been received from an MQTT broker. Supported are commands (including) 1-14.', [
                         'broker' => sprintf('%s:%s', $this->host, $this->port),
@@ -1304,6 +1301,10 @@ protected function writeToSocket(string $data, int $length = null): void
             ]);
             throw new DataTransferException(self::EXCEPTION_TX_DATA, 'Sending data over the socket failed. Has it been closed?');
         }
+        
+        // After writing successfully to the socket, the broker should have received a new message from us.
+        // Because we only need to send a ping if no other messages are delivered, we can safely reset the ping timer.
+        $this->lastPingAt = microtime(true);
     }
 
     /**