Migrated OnlyLocalRequestsAttribute into netcore

src/Umbraco.Web.Common/Extensions/HttpRequestExtensions.cs

@@ -1,4 +1,5 @@
-using Microsoft.AspNetCore.Http;
+using System.Net;
+using Microsoft.AspNetCore.Http;
 
 namespace Umbraco.Web.Common.Extensions
 {
@@ -8,5 +9,34 @@ namespace Umbraco.Web.Common.Extensions
         {
             return request.Headers.TryGetValue("X-UMB-CULTURE", out var values) ? values[0] : null;
         }
+
+        /// <summary>
+        /// Determines if a request is local.
+        /// </summary>
+        /// <returns>True if request is local</returns>
+        /// <remarks>
+        /// Hat-tip: https://stackoverflow.com/a/41242493/489433
+        /// </remarks>
+        public static bool IsLocal(this HttpRequest request)
+        {
+            var connection = request.HttpContext.Connection;
+            if (connection.RemoteIpAddress.IsSet())
+            {
+                // We have a remote address set up
+                return connection.LocalIpAddress.IsSet()
+                    // Is local is same as remote, then we are local
+                    ? connection.RemoteIpAddress.Equals(connection.LocalIpAddress)
+                    // else we are remote if the remote IP address is not a loopback address
+                    : IPAddress.IsLoopback(connection.RemoteIpAddress);
+            }
+
+            return true;
+        }
+
+        private static bool IsSet(this IPAddress address)
+        {
+            const string NullIpAddress = "::1";
+            return address != null && address.ToString() != NullIpAddress;
+        }
     }
 }