fix: Regional endpoint processing

src/Twilio/Clients/TwilioRestClient.cs

@@ -4,6 +4,7 @@
 using Newtonsoft.Json;
 using Twilio.Exceptions;
 using Twilio.AuthStrategies;
+using System.Collections.Generic;
 
 #if !NET35
 using System.Threading.Tasks;
@@ -79,6 +80,9 @@ public TwilioRestClient(
             AccountSid = accountSid ?? username;
             HttpClient = httpClient ?? DefaultClient();
 
+            if (GlobalConstants.IsOnlyOneSet(edge,region))
+                Console.WriteLine("Deprecation Warning: For regional processing, DNS is of format product.edge.region.twilio.com;otherwise use product.twilio.com");
+
             Region = region;
             Edge = edge;
         }
@@ -111,6 +115,9 @@ public TwilioRestClient(
             AccountSid = accountSid ?? username;
             HttpClient = httpClient ?? DefaultClient();
 
+            if (GlobalConstants.IsOnlyOneSet(edge,region))
+                 Console.WriteLine("Deprecation Warning: For regional processing, DNS is of format product.edge.region.twilio.com;otherwise use product.twilio.com");
+
             Region = region;
             Edge = edge;
         }
@@ -124,6 +131,12 @@ public TwilioRestClient(
         public Response Request(Request request)
         {
 
+            if (string.IsNullOrEmpty(Edge) && !string.IsNullOrEmpty(Region) && GlobalConstants.RegionToEdgeMap.TryGetValue(Region, out var edge))
+            {
+                Console.WriteLine("Deprecation Warning: Setting default `edge` for provided `region`");
+                Edge = edge;
+            }
+
             if(_username != null && _password != null){
                 request.SetAuth(_username, _password);
             }
@@ -248,7 +261,7 @@ private static Response ProcessResponse(Response response)
         }
 
         /// <summary>
-        /// Test if your environment is impacted by a TLS or certificate change 
+        /// Test if your environment is impacted by a TLS or certificate change
         /// by sending an HTTP request to the test endpoint tls-test.twilio.com:443
         /// It's a bit easier to call this method from TwilioClient.ValidateSslCertificate().
         /// </summary>

src/Twilio/Constant/GlobalConstants.cs

@@ -0,0 +1,25 @@
+using System.Collections.Generic;
+
+namespace Twilio
+{
+    public static class GlobalConstants
+    {
+        public static readonly Dictionary<string, string> RegionToEdgeMap = new Dictionary<string, string>
+        {
+            { "au1", "sydney" },
+            { "br1", "sao-paulo" },
+            { "de1", "frankfurt" },
+            { "ie1", "dublin" },
+            { "jp1", "tokyo" },
+            { "jp2", "osaka" },
+            { "sg1", "singapore" },
+            { "us1", "ashburn" },
+            { "us2", "umatilla" }
+        };
+        public static bool IsOnlyOneSet(string edge, string region)
+        {
+            return (string.IsNullOrEmpty(edge) && !string.IsNullOrEmpty(region)) ||
+                   (string.IsNullOrEmpty(region) && !string.IsNullOrEmpty(edge));
+        }
+    }
+}

src/Twilio/Twilio.cs

@@ -3,6 +3,8 @@
 using Twilio.Credential;
 using Twilio.AuthStrategies;
 using Twilio.Annotations;
+using System.Collections.Generic;
+using System;
 
 namespace Twilio
 {
@@ -13,7 +15,7 @@
     {
         private static string _username;
         private static string _password;
         private static AuthStrategy _authstrategy;
         private static string _accountSid;
         private static string _region;
         private static string _edge;
@@ -22,6 +24,7 @@
         private static string _logLevel;
         private static CredentialProvider _credentialProvider;
 
+
         private TwilioClient() { }
 
         /// <summary>
@@ -218,6 +221,15 @@
         /// <returns>The rest client</returns>
         public static ITwilioRestClient GetRestClient()
         {
+            if (GlobalConstants.IsOnlyOneSet(_edge,_region))
+                Console.WriteLine("Deprecation Warning: For regional processing, DNS is of format product.edge.region.twilio.com;otherwise use product.twilio.com");
+
+            if (string.IsNullOrEmpty(_edge) && !string.IsNullOrEmpty(_region) && GlobalConstants.RegionToEdgeMap.TryGetValue(_region, out var edge))
+            {
+                Console.WriteLine("Deprecation Warning: Setting default `edge` for provided `region`");
+                _edge = edge;
+            }
+
             if (_restClient != null)
             {
                 return _restClient;
@@ -245,7 +257,6 @@
                    LogLevel = _logLevel
                };
             }
-
             return _restClient;
         }
 
@@ -292,7 +303,7 @@
         }
 
         /// <summary>
-        /// Test if your environment is impacted by a TLS or certificate change 
+        /// Test if your environment is impacted by a TLS or certificate change
         /// by sending an HTTP request to the test endpoint tls-test.twilio.com:443
         /// </summary>
         public static void ValidateSslCertificate()

test/Twilio.Test/Clients/TwilioRestClientTest.cs

@@ -189,6 +189,33 @@ public async Task RequestAsyncWithUserAgentExtensions()
 
             Assert.AreEqual(request.UserAgentExtensions, userAgentExtensions);
         }
+
+        [Test]
+        public async Task EdgeWhenRegionIsSet()
+        {
+            client.MakeRequestAsync(Arg.Any<Request>()).Returns(new Response(HttpStatusCode.OK, "OK"));
+            Request request = new Request(HttpMethod.Get, "https://verify.twilio.com/");
+            TwilioRestClient twilioClient = new TwilioRestClient("foo", "bar", region: "us1", httpClient: client);
+
+            await twilioClient.RequestAsync(request);
+
+            Assert.AreEqual("ashburn", request.Edge);
+            Assert.AreEqual("us1", request.Region);
+        }
+
+        [Test]
+        public async Task EdgeWhenRegionIsSetAbc()
+        {
+            client.MakeRequestAsync(Arg.Any<Request>()).Returns(new Response(HttpStatusCode.OK, "OK"));
+            Request request = new Request(HttpMethod.Get, "https://verify.twilio.com/");
+            TwilioRestClient twilioClient = new TwilioRestClient("foo", "bar", region: "abc", httpClient: client);
+
+            await twilioClient.RequestAsync(request);
+
+            Assert.AreEqual("", request.Edge);
+            Assert.AreEqual("abc", request.Region);
+        }
+
 #endif
     }
 }

test/Twilio.Test/Constant/GlobalConstantsTests.cs

@@ -0,0 +1,44 @@
+using NUnit.Framework;
+using Twilio.Constant;
+using System.Collections.Generic;
+
+namespace Twilio.Tests
+{
+    [TestFixture]
+    public class GlobalConstantsTests
+    {
+        [TestCase(null, null, ExpectedResult = false)]
+        [TestCase("", "", ExpectedResult = false)]
+        [TestCase("edge", null, ExpectedResult = true)]
+        [TestCase(null, "region", ExpectedResult = true)]
+        [TestCase("edge", "", ExpectedResult = true)]
+        [TestCase("", "region", ExpectedResult = true)]
+        [TestCase("edge", "region", ExpectedResult = false)]
+        public bool IsOnlyOneSet_ReturnsExpected(string edge, string region)
+        {
+            return GlobalConstants.IsOnlyOneSet(edge, region);
+        }
+    }
+
+    [TestFixture]
+        public class GlobalConstantsMapTests
+        {
+            [Test]
+            public void RegionToEdgeMap_ContainsExpectedEntries()
+            {
+                // Example: adjust key-value pairs to match your actual map
+                Assert.IsTrue(GlobalConstants.RegionToEdgeMap.ContainsKey("us1"));
+                Assert.AreEqual("ashburn", GlobalConstants.RegionToEdgeMap["us1"]);
+
+                Assert.IsTrue(GlobalConstants.RegionToEdgeMap.ContainsKey("ie1"));
+                Assert.AreEqual("dublin", GlobalConstants.RegionToEdgeMap["ie1"]);
+            }
+
+            [Test]
+            public void RegionToEdgeMap_DoesNotContainUnexpectedKey()
+            {
+                Assert.IsFalse(GlobalConstants.RegionToEdgeMap.ContainsKey("unexpected"));
+            }
+        }
+
+}