get the refresh period from the token

Azure-Samples · Jun 28, 2024 · fd15f58 · fd15f58
1 parent e0411ee
commit fd15f58
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Showing 2 changed files with 10 additions and 8 deletions.
diff --git a/mqttclients/dotnet/MQTTnet.Client.Extensions/WithJWT.cs b/mqttclients/dotnet/MQTTnet.Client.Extensions/WithJWT.cs
@@ -4,19 +4,21 @@ namespace MQTTnet.Client.Extensions
 {
     public static partial class MqttNetExtensions
     {
-        static Func<byte[]> _getTokenCallBack = null!;
+        static Func<(byte[], TimeSpan)> _getTokenCallBack = null!;
         static Timer _refreshTimer = null!;
 
 
-        public static MqttClientOptionsBuilder WithJWT(this MqttClientOptionsBuilder builder, MqttConnectionSettings cs, Func<byte[]> getTokenCallBack, IMqttClient mqttClient, TimeSpan refreshPeriod)
+        public static MqttClientOptionsBuilder WithJWT(this MqttClientOptionsBuilder builder, MqttConnectionSettings cs, Func<(byte[], TimeSpan)> getTokenCallBack, IMqttClient mqttClient)
         {
             _getTokenCallBack = getTokenCallBack;
 
+            (byte[] token, TimeSpan ts) = getTokenCallBack();
+            Trace.TraceInformation($"Token expires in {ts.TotalSeconds} seconds");
             builder
                 .WithConnectionSettings(cs)
-                .WithAuthentication("OAUTH2-JWT", getTokenCallBack());
+                .WithAuthentication("OAUTH2-JWT", token);
 
-            _refreshTimer = new Timer(RefreshToken, mqttClient, 0, Convert.ToInt32(refreshPeriod.TotalMilliseconds));
+            _refreshTimer = new Timer(RefreshToken, mqttClient, 0, (int)ts.TotalSeconds * 1000);
             return builder;
         }
 
@@ -30,7 +32,7 @@ static void RefreshToken(object? state)
                     await mqttClient.SendExtendedAuthenticationExchangeDataAsync(
                         new MqttExtendedAuthenticationExchangeData()
                         {
-                            AuthenticationData = _getTokenCallBack(),
+                            AuthenticationData = _getTokenCallBack().Item1,
                             ReasonCode = MQTTnet.Protocol.MqttAuthenticateReasonCode.ReAuthenticate
                         });
                 });

diff --git a/scenarios/jwt_authentication/dotnet/jwt_authentication/Program.cs b/scenarios/jwt_authentication/dotnet/jwt_authentication/Program.cs
@@ -12,7 +12,7 @@
 
 IMqttClient mqttClient = new MqttFactory().CreateMqttClient(MqttNetTraceLogger.CreateTraceLogger());
 MqttClientConnectResult connAck = await mqttClient!.ConnectAsync(new MqttClientOptionsBuilder()
-    .WithJWT(cs, GetToken, mqttClient, TimeSpan.FromHours(1))
+    .WithJWT(cs, GetToken, mqttClient)
     .Build());
 
 Console.WriteLine($"Client Connected: {mqttClient.IsConnected} with CONNACK: {connAck.ResultCode} with auth method {mqttClient.Options.AuthenticationMethod}");
@@ -33,10 +33,10 @@
     await Task.Delay(10000);
 }    
 
-static byte[] GetToken()
+static (byte[], TimeSpan) GetToken()
 {
     DefaultAzureCredential defaultCredential = new();
     Console.WriteLine($"---- Get Token {DateTime.Now.ToString("o")} ----");
     AccessToken jwt = defaultCredential.GetToken(new TokenRequestContext(new string[] { "https://eventgrid.azure.net/.default" }));
-    return Encoding.UTF8.GetBytes(jwt.Token);
+    return (Encoding.UTF8.GetBytes(jwt.Token), jwt.ExpiresOn.Subtract(DateTime.UtcNow));
 }