Support for automatic reconnects

README.md

@@ -155,6 +155,15 @@ $connectionSettings = (new \PhpMqtt\Client\ConnectionSettings)
     // of pending messages without acknowledgement. The value cannot be less than 1 second.
     ->setResendTimeout(10)
 
+    // This flag determines whether the client will try to reconnect automatically
+    // if it notices a disconnect while sending data.
+    // The setting cannot be used together with the clean session flag.
+    ->setReconnectAutomatically(false)
+
+    // Defines the maximum number of reconnect attempts until the client gives up.
+    // This setting is only relevant if setReconnectAutomatically() is set to true.
+    ->setMaxReconnectAttempts(3)
+
     // The keep alive interval is the number of seconds the client will wait without sending a message
     // until it sends a keep alive signal (ping) to the broker. The value cannot be less than 1 second
     // and may not be higher than 65535 seconds. A reasonable value is 10 seconds (the default).

src/Concerns/ValidatesConfiguration.php

@@ -43,6 +43,10 @@ protected function ensureConnectionSettingsAreValid(ConnectionSettings $settings
             throw new ConfigurationInvalidException('The keep alive interval must be a value in the range of 1 to 65535 seconds.');
         }
 
+        if ($settings->getMaxReconnectAttempts() < 1) {
+            throw new ConfigurationInvalidException('The maximum reconnect attempts cannot be fewer than 1.');
+        }
+
         if ($settings->getUsername() !== null && trim($settings->getUsername()) === '') {
             throw new ConfigurationInvalidException('The username may not consist of white space only.');
         }

src/ConnectionSettings.php

@@ -17,6 +17,8 @@ class ConnectionSettings
     private int $socketTimeout                         = 5;
     private int $resendTimeout                         = 10;
     private int $keepAliveInterval                     = 10;
+    private bool $reconnectAutomatically               = false;
+    private int $maxReconnectAttempts                  = 3;
     private ?string $lastWillTopic                     = null;
     private ?string $lastWillMessage                   = null;
     private int $lastWillQualityOfService              = 0;
@@ -175,6 +177,55 @@ public function getKeepAliveInterval(): int
         return $this->keepAliveInterval;
     }
 
+    /**
+     * This flag determines whether the client will try to reconnect automatically,
+     * if it notices a disconnect while sending data.
+     * The setting cannot be used together with the clean session flag.
+     *
+     * @param bool $reconnectAutomatically
+     * @return ConnectionSettings
+     */
+    public function setReconnectAutomatically(bool $reconnectAutomatically): ConnectionSettings
+    {
+        $copy = clone $this;
+
+        $copy->reconnectAutomatically = $reconnectAutomatically;
+
+        return $copy;
+    }
+
+    /**
+     * @return bool
+     */
+    public function shouldReconnectAutomatically(): bool
+    {
+        return $this->reconnectAutomatically;
+    }
+
+    /**
+     * Defines the maximum number of reconnect attempts until the client gives up. This setting
+     * is only relevant if {@see setReconnectAutomatically()} is set to true.
+     *
+     * @param int $maxReconnectAttempts
+     * @return ConnectionSettings
+     */
+    public function setMaxReconnectAttempts(int $maxReconnectAttempts): ConnectionSettings
+    {
+        $copy = clone $this;
+
+        $copy->maxReconnectAttempts = $maxReconnectAttempts;
+
+        return $copy;
+    }
+
+    /**
+     * @return int
+     */
+    public function getMaxReconnectAttempts(): int
+    {
+        return $this->maxReconnectAttempts;
+    }
+
     /**
      * If the broker should publish a last will message in the name of the client when the client
      * disconnects abruptly, this setting defines the topic on which the message will be published.