Make token exchange audience configurable

Author: whamm86

src/AasSecurity/SecurityService.cs

@@ -482,6 +482,14 @@ private string HandleBearerToken(string? bearerToken, ref string user, ref bool
                         if (!string.IsNullOrEmpty(tokenExchange1) && !string.IsNullOrEmpty(tokenExchange2)
                             && iss == tokenExchange1)
                         {
+                            var audience = "fa3st";
+                            var audienceEnvVar = System.Environment.GetEnvironmentVariable("TOKENEXCHANGE_AUDIENCE");
+
+                            if (!string.IsNullOrEmpty(audienceEnvVar))
+                            {
+                                audience = audienceEnvVar;
+                            }
+
                             Console.WriteLine($"TOKENEXCHANGE1 = {tokenExchange1}");
                             Console.WriteLine($"TOKENEXCHANGE2 = {tokenExchange2}");
                             var handlerExchange = new HttpClientHandler { DefaultProxyCredentials = CredentialCache.DefaultCredentials };
@@ -494,7 +502,7 @@ private string HandleBearerToken(string? bearerToken, ref string user, ref bool
                                 { "subject_token_type", "urn:ietf:params:oauth:token-type:jwt" },
                                 { "requested_token_type", "urn:ietf:params:oauth:token-type:access_token" },
                                 { "subject_token", bearerToken },
-                                { "audience", "fa3st" }
+                                { "audience", audience }
                             };
                             var request = new HttpRequestMessage(HttpMethod.Post, $"{tokenExchange2}/token")
                             {

src/AasxServerBlazor/Properties/launchSettings.json

@@ -20,7 +20,8 @@
         "EVENT2": "http://localhost:5002/submodels/aHR0cHM6Ly9pNGQuZGUvVC8zMjA5NTEwL3N1Ym1vZGVsL05hbWVwbGF0ZS9yZWNlaXZlcg/events/EventElement1",
         "AASX_MQTT": "1",
         "TOKENEXCHANGE1": "https://iam-security-training.com/consumer/sts",
-        "TOKENEXCHANGE2": "https://iam-security-training.com/provider/sts"
+        "TOKENEXCHANGE2": "https://iam-security-training.com/provider/sts",
+        "TOKENEXCHANGE_AUDIENCE": "fa3st"
       },
       "applicationUrl": "http://localhost:5001",
       "jsWebView2Debugging": true