Added more validation to the various AuthController functions.

SecureCore/Services/UserDataService.cs

@@ -11,6 +11,7 @@ namespace SecureCore.Services
     {
         //
         public static int UserNameMaxLength { get; } = 64;
+        public static int EmailMaxLength { get; } = 512;
 
         public static (bool IsValid, string Message) IsUsernameValid(string userName)
         {
@@ -29,7 +30,6 @@ namespace SecureCore.Services
         public static int RegisterNewUser(string userName, string email, string passwordHash, string saltHash, string sessionToken, DateTime expirationDate, string userAgent, string ipAddress, string connectionString)
         {
             using var connection = new SqlConnection(connectionString);
-
             using var command = new SqlCommand("RegisterNewUser", connection) { CommandType = CommandType.StoredProcedure };
 
             command.Parameters.AddWithValue("UserName", userName);
@@ -47,5 +47,36 @@ namespace SecureCore.Services
 
             return Convert.ToInt32(result);
         }
+
+        public static bool IsEmailInUse(string email, string connectionString)
+        {
+            using var connection = new SqlConnection(connectionString);
+            using var command = new SqlCommand("SELECT dbo.EmailInUse(@Email) AS InUse", connection);
+
+            command.Parameters.AddWithValue("Email", email);
+
+            connection.Open();
+
+            return Convert.ToBoolean(command.ExecuteScalar());
+        }
+
+        public static (bool IsValid, string Message) IsEmailValid(string email)
+        {
+            if (email.Length > EmailMaxLength) return (false, $"Email exceeds the maximum length of {EmailMaxLength} characters.");
+
+            //Code taken from user "Cogwheel" on StackOverflow: https://stackoverflow.com/questions/1365407/c-sharp-code-to-validate-email-address
+            try
+            {
+                var addr = new System.Net.Mail.MailAddress(email);
+
+                if (addr.Address != email) return (false, $"The provided email is not in the correct format.");
+
+                return (true, string.Empty);
+            }
+            catch
+            {
+                return (false, $"The provided email is not in the correct format.");
+            }
+        }
     }
 }