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--- mqttics [2024/11/22 03:01] – created jwan
+++ mqttics [2025/10/10 10:15] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
+===== N O T I C E =====
+ICS's SSL is enabled by default, which is required for MQTT to function.  However, with SSL enabled, the compiled EXE file will increase significantly.  **If SSL is not use, it can be disabled by commenting out __{$DEFINE USE_SSL}__ inside \Source\Include\OverbyteIcsDefs.inc file. This is in #273 in ICS v9.4**
+----
 **Using ICS v9.3**
@@ Line 48: / Line 57: @@
     end;
 end;
+</code>
+Below is fully working sample:
+<code>
+unit main;
+interface
+uses
+  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
+  Dialogs, StdCtrls, OverbyteIcsMQTT, OverbyteIcsWndControl,
+  OverbyteIcsSslX509Certs,McJSON;
+type
+  Tiotmqttsql = class(TForm)
+    mmo: TMemo;
+    mqttclient: TIcsMQTTClient;
+    edtpublish: TEdit;
+    btnpublish: TButton;
+    slx509crts1: TSslX509Certs;
+    icsmqtclnt1: TIcsMQTTClient;
+    procedure FormShow(Sender: TObject);
+    procedure FormClose(Sender: TObject; var Action: TCloseAction);
+    procedure mqttclientMsg(Sender: TObject; aTopic: UTF8String; const aMessage: String; aQos: TMQTTQOSType; aRetained: Boolean);
+    procedure btnpublishClick(Sender: TObject);
+    procedure mqttclientOnline(Sender: TObject);
+    procedure mqttclientOffline(Sender: TObject; Graceful: Boolean);
+    procedure mqttclientClientID(Sender: TObject;
+      var aClientID: UTF8String);
+  private
+    { Private declarations }
+  public
+    { Public declarations }
+  end;
+var
+  iotmqttsql: Tiotmqttsql;
+const
+   mqtttopic : string = 'topicname';
+   mqtthost  : string = 'sample.com';
+implementation
+{$R *.dfm}
+procedure Tiotmqttsql.FormShow(Sender: TObject);
+begin
+   mmo.lines.clear;
+   mqttclient.AutoSubscribe := true;
+   mqttclient.host := mqtthost;
+   mqttclient.Port := 1883;
+   mqttclient.KeepAlive := 10;
+   mqttclient.Activate(true);
+   mqttclient.Subscribe(mqtttopic,qtAT_LEAST_ONCE);
+end;
+procedure Tiotmqttsql.FormClose(Sender: TObject; var Action: TCloseAction);
+begin
+   mqttclient.Destroy;
+end;
+procedure Tiotmqttsql.mqttclientMsg(Sender: TObject; aTopic: UTF8String; const aMessage: String; aQos: MQTTQOSType; aRetained: Boolean);
+begin
+   mmo.Lines.Add(FormatDateTime('yyyy-MM-dd',now())+': '+aMessage+#13#10);
+end;
+procedure Tiotmqttsql.btnpublishClick(Sender: TObject);
+begin
+   mqttclient.Publish(mqtttopic,edtpublish.Text,qtAT_LEAST_ONCE,true);
+end;
+procedure Tiotmqttsql.mqttclientOnline(Sender: TObject);
+begin
+//   mmo.Lines.add('Online');
+end;
+procedure Tiotmqttsql.mqttclientOffline(Sender: TObject;  Graceful: Boolean);
+begin
+//   mmo.Lines.add('Offline');
+end;
+procedure Tiotmqttsql.mqttclientClientID(Sender: TObject; var aClientID: UTF8String);
+begin
+   mmo.Lines.add('Client ID: '+aClientID);
+end;
+end.
 </code>