Port GetUserId/UserName IIdentity extensions

src/Microsoft.AspNet.Identity.Security/IdentityExtensions.cs

@@ -0,0 +1,56 @@
+using System.Security.Claims;
+
+namespace System.Security.Principal
+{
+    /// <summary>
+    ///     Extensions making it easier to get the user name/user id claims off of an identity
+    /// </summary>
+    public static class IdentityExtensions
+    {
+        /// <summary>
+        ///     Return the user name using the UserNameClaimType
+        /// </summary>
+        /// <param name="identity"></param>
+        /// <returns></returns>
+        public static string GetUserName(this IIdentity identity)
+        {
+            if (identity == null)
+            {
+                throw new ArgumentNullException("identity");
+            }
+            var ci = identity as ClaimsIdentity;
+            return ci != null ? ci.FindFirstValue(ClaimsIdentity.DefaultNameClaimType) : null;
+        }
+
+        /// <summary>
+        ///     Return the user id using the UserIdClaimType
+        /// </summary>
+        /// <param name="identity"></param>
+        /// <returns></returns>
+        public static string GetUserId(this IIdentity identity)
+        {
+            if (identity == null)
+            {
+                throw new ArgumentNullException("identity");
+            }
+            var ci = identity as ClaimsIdentity;
+            return ci != null ? ci.FindFirstValue(ClaimTypes.NameIdentifier) : null;
+        }
+
+        /// <summary>
+        ///     Return the claim value for the first claim with the specified type if it exists, null otherwise
+        /// </summary>
+        /// <param name="identity"></param>
+        /// <param name="claimType"></param>
+        /// <returns></returns>
+        public static string FindFirstValue(this ClaimsIdentity identity, string claimType)
+        {
+            if (identity == null)
+            {
+                throw new ArgumentNullException("identity");
+            }
+            var claim = identity.FindFirst(claimType);
+            return claim != null ? claim.Value : null;
+        }
+    }
+}

test/Microsoft.AspNet.Identity.Security.Test/IdentityExtensionsTest.cs

@@ -0,0 +1,74 @@
+using System;
+using System.Security.Claims;
+using System.Security.Principal;
+using Xunit;
+
+namespace Microsoft.AspNet.Identity.Security.Test
+{
+    public class IdentityExtensionsTest
+    {
+        public const string ExternalAuthenticationType = "TestExternalAuth";
+
+        [Fact]
+        public void IdentityNullCheckTest()
+        {
+            IIdentity identity = null;
+            Assert.Throws<ArgumentNullException>("identity", () => identity.GetUserId());
+            Assert.Throws<ArgumentNullException>("identity", () => identity.GetUserName());
+            ClaimsIdentity claimsIdentity = null;
+            Assert.Throws<ArgumentNullException>("identity", () => claimsIdentity.FindFirstValue(null));
+        }
+
+        [Fact]
+        public void IdentityNullIfNotClaimsIdentityTest()
+        {
+            IIdentity identity = new TestIdentity();
+            Assert.Null(identity.GetUserId());
+            Assert.Null(identity.GetUserName());
+        }
+
+        [Fact]
+        public void UserNameAndIdTest()
+        {
+            var id = CreateTestExternalIdentity();
+            Assert.Equal("NameIdentifier", id.GetUserId());
+            Assert.Equal("Name", id.GetUserName());
+        }
+
+        [Fact]
+        public void IdentityExtensionsFindFirstValueNullIfUnknownTest()
+        {
+            var id = CreateTestExternalIdentity();
+            Assert.Null(id.FindFirstValue("bogus"));
+        }
+
+        private static ClaimsIdentity CreateTestExternalIdentity()
+        {
+            return new ClaimsIdentity(
+                new[]
+                {
+                    new Claim(ClaimTypes.NameIdentifier, "NameIdentifier", null, ExternalAuthenticationType),
+                    new Claim(ClaimTypes.Name, "Name")
+                },
+                ExternalAuthenticationType);
+        }
+
+        private class TestIdentity : IIdentity
+        {
+            public string AuthenticationType
+            {
+                get { throw new NotImplementedException(); }
+            }
+
+            public bool IsAuthenticated
+            {
+                get { throw new NotImplementedException(); }
+            }
+
+            public string Name
+            {
+                get { throw new NotImplementedException(); }
+            }
+        }
+    }
+}