Fixed Verifiy email using regex and modified Login action

src/Fan/Helpers/RegexUtilities.cs

@@ -4,12 +4,16 @@
 
 namespace Fan.Helpers
 {
+    /// <summary>
+    /// A util class that uses regular expression to verify if a string is in valid email format.
+    /// </summary>
+    /// <remarks>
+    /// https://docs.microsoft.com/en-us/dotnet/standard/base-types/how-to-verify-that-strings-are-in-valid-email-format
+    /// </remarks>
     public static class RegexUtilities
     {
-        private static bool _invalid = false;
-        public static bool IsValidEmail(this string strIn)
+        public static bool IsValidEmail(string strIn)
         {
-
             if (String.IsNullOrEmpty(strIn))
                 return false;
 
@@ -18,15 +22,14 @@ public static bool IsValidEmail(this string strIn)
             {
                 strIn = Regex.Replace(strIn, @"(@)(.+)$", DomainMapper,
                                       RegexOptions.None, TimeSpan.FromMilliseconds(200));
+                if(string.IsNullOrEmpty(strIn))
+                    return false;
             }
-            catch (RegexMatchTimeoutException)
+            catch (Exception ex)
             {
-                return false;
+                if(ex is RegexMatchTimeoutException || ex is ArgumentNullException)
+                    return false;
             }
-
-            if (_invalid)
-                return false;
-
             // Return true if strIn is in valid email format.
             try
             {
@@ -53,7 +56,7 @@ private static string DomainMapper(Match match)
             }
             catch (ArgumentException)
             {
-                _invalid = true;
+                return null; 
             }
             return match.Groups[1].Value + domainName;
         }

src/Fan/Membership/UserService.cs

@@ -1,9 +1,7 @@
-using Microsoft.AspNetCore.Identity;
+using Fan.Helpers;
+using Microsoft.AspNetCore.Identity;
 using Microsoft.Extensions.Logging;
-using System;
-using System.Net.Mail;
 using System.Threading.Tasks;
-using Fan.Helpers;
 
 namespace Fan.Membership
 {
@@ -25,8 +23,7 @@ public class UserService : IUserService
         /// <returns></returns>
         public async Task<User> FindByEmailOrUsernameAsync(string emailOrUsername)
         {
-            bool isEmail = emailOrUsername.IsValidEmail();
-            // get user
+            bool isEmail = RegexUtilities.IsValidEmail(emailOrUsername);
             return isEmail ? await _userManager.FindByEmailAsync(emailOrUsername) :
                 await _userManager.FindByNameAsync(emailOrUsername);
         }

test/Fan.UnitTests/Helpers/RegexUtilitiesTest.cs

@@ -1,59 +1,40 @@
 using Fan.Helpers;
-using Fan.Membership;
-using System.Collections.Generic;
 using Xunit;
+
 namespace Fan.UnitTests.Helpers
 {
     /// <summary>
     /// Test for <see cref="RegexUtilities"/> class.
     /// </summary>
     public class RegexUtilitiesTest
     {
-        [Fact]
-        public void RegexUtilities_Valid_Email_Address()
-        {
-            // list valid email addres
-            string[] emailAddresses = { "david.jones@proseware.com", "d.j@server1.proseware.com",
-                                  "jones@ms1.proseware.com",
-                                  "j@proseware.com9", "js#internal@proseware.com",
-                                  "j_9@[129.126.118.1]",
-                                  "js@proseware.com9", "j.s@server1.proseware.com",
-                                   "\"j\\\"s\\\"\"@proseware.com", "js@contoso.中国" };
-            // Act: valid email
-            var valid = true;
-            foreach (var item in emailAddresses)
-            {
-                var result = RegexUtilities.IsValidEmail(item);
-
-                if(!result)
-                //if item is Invalid email address
-                    valid = result;
-            }
-            // Assert
-            Assert.True(valid);
-
-        }
-
-        [Fact]
-        public void RegexUtilities_InValid_Email_Address()
+        /// <summary>
+        /// Test cases for <see cref="RegexUtilities.IsValidEmail(string)"/> method.
+        /// </summary>
+        /// <param name="email"></param>
+        /// <param name="expected"></param>
+        /// <remarks>
+        /// Test data provided by https://docs.microsoft.com/en-us/dotnet/standard/base-types/how-to-verify-that-strings-are-in-valid-email-format#compiling-the-code
+        /// </remarks>
+        [Theory]
+        [InlineData("david.jones@proseware.com", true)]
+        [InlineData("d.j@server1.proseware.com", true)]
+        [InlineData("jones@ms1.proseware.com", true)]
+        [InlineData("j.@server1.proseware.com", false)]
+        [InlineData("j@proseware.com9", true)]
+        [InlineData("js#internal@proseware.com", true)]
+        [InlineData("j_9@[129.126.118.1]", true)]
+        [InlineData("j..s@proseware.com", false)]
+        [InlineData("js*@proseware.com", false)]
+        [InlineData("js@proseware..com", false)]
+        [InlineData("js@proseware.com9", true)]
+        [InlineData("j.s@server1.proseware.com", true)]
+        [InlineData(@"""j\""s\""""@proseware.com", true)]
+        [InlineData("js@contoso.中国", true)]
+        [InlineData("username", false)]
+        public void IsValidEmail_Test(string email, bool expected)
         {
-            // list invalid email addres
-            string[] emailAddresses = {"j.@server1.proseware.com","j..s@proseware.com","js*@proseware.com","js@proseware..com","username"};
-
-            // Act: valid email
-            var valid = true;
-            foreach (var item in emailAddresses)
-            {
-                var result = RegexUtilities.IsValidEmail(item);
-
-                if(!result)
-                //if item is Invalid email address
-                    valid = result;
-            }
-            // Assert
-            Assert.True(!valid);
-
-
+            Assert.Equal(expected, RegexUtilities.IsValidEmail(email));
         }
     }
 }