Using WebEncoders' Base64Url encode/decode functionality

Author: kichalla

src/Microsoft.AspNetCore.WebUtilities/Base64UrlTextEncoder.cs

@@ -1,10 +1,6 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
-using System;
-using System.Text;
-using Microsoft.Extensions.Primitives;
-
 namespace Microsoft.AspNetCore.WebUtilities
 {
     public static class Base64UrlTextEncoder
@@ -17,8 +13,7 @@ public static class Base64UrlTextEncoder
         /// <returns>Base64 encoded string modified with non-URL encodable characters</returns>
         public static string Encode(byte[] data)
         {
-            var encodedValue = Convert.ToBase64String(data);
-            return EncodeInternal(encodedValue);
+            return WebEncoders.Base64UrlEncode(data);
         }
 
         /// <summary>
@@ -29,76 +24,7 @@ public static string Encode(byte[] data)
         /// <returns>The decoded data.</returns>
         public static byte[] Decode(string text)
         {
-            return Convert.FromBase64String(DecodeToBase64String(text));
-        }
-
-        // To enable unit testing
-        internal static string EncodeInternal(string base64EncodedString)
-        {
-            var length = base64EncodedString.Length;
-            while (length > 0 && base64EncodedString[length - 1] == '=')
-            {
-                length--;
-            }
-
-            if (length == 0)
-            {
-                return string.Empty;
-            }
-
-            var inplaceStringBuilder = new InplaceStringBuilder(length);
-            for (var i = 0; i < length; i++)
-            {
-                if (base64EncodedString[i] == '+')
-                {
-                    inplaceStringBuilder.Append('-');
-                }
-                else if (base64EncodedString[i] == '/')
-                {
-                    inplaceStringBuilder.Append('_');
-                }
-                else
-                {
-                    inplaceStringBuilder.Append(base64EncodedString[i]);
-                }
-            }
-
-            return inplaceStringBuilder.ToString();
-        }
-
-        // To enable unit testing
-        internal static string DecodeToBase64String(string text)
-        {
-            if (string.IsNullOrEmpty(text))
-            {
-                return text;
-            }
-
-            var padLength = 3 - ((text.Length + 3) % 4);
-            var inplaceStringBuilder = new InplaceStringBuilder(capacity: text.Length + padLength);
-
-            for (var i = 0; i < text.Length; i++)
-            {
-                if (text[i] == '-')
-                {
-                    inplaceStringBuilder.Append('+');
-                }
-                else if (text[i] == '_')
-                {
-                    inplaceStringBuilder.Append('/');
-                }
-                else
-                {
-                    inplaceStringBuilder.Append(text[i]);
-                }
-            }
-
-            for (var i = 0; i < padLength; i++)
-            {
-                inplaceStringBuilder.Append('=');
-            }
-
-            return inplaceStringBuilder.ToString();
+            return WebEncoders.Base64UrlDecode(text);
         }
     }
 }

test/Microsoft.AspNetCore.WebUtilities.Tests/Base64UrlTextEncoderTests.cs

@@ -2,13 +2,13 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Linq;
 using Xunit;
 
 namespace Microsoft.AspNetCore.WebUtilities
 {
     public class WebEncodersTests
     {
+
         [Theory]
         [InlineData("", 1, 0)]
         [InlineData("", 0, 1)]
@@ -41,5 +41,25 @@ public void Base64UrlEncode_BadOffsets(int inputLength, int offset, int count)
                 var retVal = WebEncoders.Base64UrlEncode(input, offset, count);
             });
         }
+
+        [Fact]
+        public void DataOfVariousLengthRoundTripCorrectly()
+        {
+            for (int length = 0; length != 256; ++length)
+            {
+                var data = new byte[length];
+                for (int index = 0; index != length; ++index)
+                {
+                    data[index] = (byte)(5 + length + (index * 23));
+                }
+                string text = WebEncoders.Base64UrlEncode(data);
+                byte[] result = WebEncoders.Base64UrlDecode(text);
+
+                for (int index = 0; index != length; ++index)
+                {
+                    Assert.Equal(data[index], result[index]);
+                }
+            }
+        }
     }
 }