1 files changed, 63 insertions, 0 deletions
diff --git a/MediaBrowser.Common/Extensions/HttpContextExtensions.cs b/MediaBrowser.Common/Extensions/HttpContextExtensions.cs
new file mode 100644
index 000000000..e0cf3f9ac
--- /dev/null
+++ b/MediaBrowser.Common/Extensions/HttpContextExtensions.cs
@@ -0,0 +1,63 @@
+using System.Net;
+using MediaBrowser.Common.Net;
+using Microsoft.AspNetCore.Http;
+
+namespace MediaBrowser.Common.Extensions
+{
+    /// <summary>
+    /// Static class containing extension methods for <see cref="HttpContext"/>.
+    /// </summary>
+    public static class HttpContextExtensions
+    {
+        /// <summary>
+        /// Checks the origin of the HTTP request.
+        /// </summary>
+        /// <param name="request">The incoming HTTP request.</param>
+        /// <returns><c>true</c> if the request is coming from LAN, <c>false</c> otherwise.</returns>
+        public static bool IsLocal(this HttpRequest request)
+        {
+            return (request.HttpContext.Connection.LocalIpAddress == null
+                    && request.HttpContext.Connection.RemoteIpAddress == null)
+                   || request.HttpContext.Connection.LocalIpAddress.Equals(request.HttpContext.Connection.RemoteIpAddress);
+        }
+
+        /// <summary>
+        /// Extracts the remote IP address of the caller of the HTTP request.
+        /// </summary>
+        /// <param name="request">The HTTP request.</param>
+        /// <returns>The remote caller IP address.</returns>
+        public static string RemoteIp(this HttpRequest request)
+        {
+            var cachedRemoteIp = request.HttpContext.Items["RemoteIp"]?.ToString();
+            if (!string.IsNullOrEmpty(cachedRemoteIp))
+            {
+                return cachedRemoteIp;
+            }
+
+            IPAddress ip;
+
+            // "Real" remote ip might be in X-Forwarded-For of X-Real-Ip
+            // (if the server is behind a reverse proxy for example)
+            if (!IPAddress.TryParse(request.Headers[CustomHeaderNames.XForwardedFor].ToString(), out ip))
+            {
+                if (!IPAddress.TryParse(request.Headers[CustomHeaderNames.XRealIP].ToString(), out ip))
+                {
+                    ip = request.HttpContext.Connection.RemoteIpAddress;
+
+                    // Default to the loopback address if no RemoteIpAddress is specified (i.e. during integration tests)
+                    ip ??= IPAddress.Loopback;
+                }
+            }
+
+            if (ip.IsIPv4MappedToIPv6)
+            {
+                ip = ip.MapToIPv4();
+            }
+
+            var normalizedIp = ip.ToString();
+
+            request.HttpContext.Items["RemoteIp"] = normalizedIp;
+            return normalizedIp;
+        }
+    }
+}