Removed custom base64url encoding

Author: scottbrady91

src/IdentityManager2/Extensions/EncodingExtensions.cs

@@ -1,5 +1,5 @@
-using System;
-using System.Text;
+using System.Text;
+using Microsoft.AspNetCore.Authentication;
 
 namespace IdentityManager2.Extensions
 {
@@ -8,48 +8,13 @@ public static class EncodingExtensions
         public static string ToBase64UrlEncoded(this string s)
         {
             if (s == null) return null;
-
-            var bytes = Encoding.UTF8.GetBytes(s);
-
-            return bytes.ToBase64UrlEncoded();
-        }
-
-        public static string ToBase64UrlEncoded(this byte[] bytes)
-        {
-            if (bytes == null) return null;
-            
-            var s = Convert.ToBase64String(bytes);
-            s = s.Split('=')[0]; // Remove any trailing '='s
-            s = s.Replace('+', '-'); // 62nd char of encoding
-            s = s.Replace('/', '_'); // 63rd char of encoding
-
-            return s;
+            return Base64UrlTextEncoder.Encode(Encoding.UTF8.GetBytes(s));
         }
 
         public static string FromBase64UrlEncoded(this string s)
         {
             if (s == null) return null;
-
-            var bytes = s.FromBase64UrlEncodedBytes();
-            return Encoding.UTF8.GetString(bytes);
-        }
-
-        public static byte[] FromBase64UrlEncodedBytes(this string s)
-        {
-            if (s == null) return null;
-
-            s = s.Replace('-', '+'); // 62nd char of encoding
-            s = s.Replace('_', '/'); // 63rd char of encoding
-
-            switch (s.Length % 4) // Pad with trailing '='s
-            {
-                case 0: break; // No pad chars in this case
-                case 2: s += "=="; break; // Two pad chars
-                case 3: s += "="; break; // One pad char
-                default: throw new Exception("Illegal base64url string!");
-            }
-
-            return Convert.FromBase64String(s);
+            return Encoding.UTF8.GetString(Base64UrlTextEncoder.Decode(s));
         }
     }
 }