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Source/MQTTnet.PowerShell/Cmdlets/PublishMqttMessageCmdlet.cs

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+using System.Management.Automation;
+using System.Text;
+using MQTTnet.Protocol;
+
+namespace MQTTnet.PowerShell.Cmdlets;
+
+[Cmdlet(VerbsData.Publish, "MqttMessage")]
+public class PublishMqttMessageCmdlet : PSCmdlet
+{
+    [Parameter(Mandatory = true)]
+    public string? Payload { get; set; }
+
+    [Parameter]
+    public int QoS { get; set; } = 0;
+
+    [Parameter]
+    public SwitchParameter Retain { get; set; }
+
+    [Parameter(Mandatory = true, ValueFromPipeline = true)]
+    public required MqttSession Session { get; set; }
+
+    [Parameter(Mandatory = true)]
+    public required string Topic { get; set; }
+
+    protected override void ProcessRecord()
+    {
+        // if (Session == null || !Session.IsConnected)
+        //     throw new InvalidOperationException("Session not connected.");
+
+        var msg = new MqttApplicationMessageBuilder().WithTopic(Topic)
+            .WithPayload(Encoding.UTF8.GetBytes(Payload ?? string.Empty))
+            .WithQualityOfServiceLevel((MqttQualityOfServiceLevel)QoS)
+            .WithRetainFlag(Retain)
+            .Build();
+
+        var response = Session.Client.PublishAsync(msg).GetAwaiter().GetResult();
+
+        WriteObject(response);
+    }
+}