Case insensitive session keys JSON serializer (#540)

Author: arnoj

src/Microsoft.AspNetCore.SystemWebAdapters.Abstractions/SessionState/Serialization/JsonSessionSerializerOptions.cs

@@ -11,10 +11,31 @@ namespace Microsoft.AspNetCore.SystemWebAdapters.SessionState.Serialization;
 /// </summary>
 public class JsonSessionSerializerOptions
 {
+    public JsonSessionSerializerOptions()
+    {
+        _keyComparer = StringComparer.Ordinal;
+        KnownKeys = new Dictionary<string, Type>(_keyComparer);
+    }
+
+    private IEqualityComparer<string> _keyComparer;
+
+    /// <summary>
+    /// Gets or or sets the equality comparer for the known session keys.
+    /// </summary>
+    public IEqualityComparer<string> KeyComparer
+    {
+        get => _keyComparer;
+        set
+        {
+            _keyComparer = value;
+            KnownKeys = new Dictionary<string, Type>(KnownKeys, _keyComparer);
+        }
+    }
+
     /// <summary>
     /// Gets the mapping of known session keys to types
     /// </summary>
-    public IDictionary<string, Type> KnownKeys { get; } = new Dictionary<string, Type>();
+    public IDictionary<string, Type> KnownKeys { get; private set; }
 
     /// <summary>
     /// Registers a session key name to be of type <typeparamref name="T"/>

test/Microsoft.AspNetCore.SystemWebAdapters.CoreServices.Tests/SessionState/Serialization/JsonSessionKeySerializerTests.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System;
 using System.Globalization;
 using System.Linq;
 using System.Text;
@@ -293,6 +294,70 @@ public void PrimitiveNullableSerializer(int? primitive)
         Assert.Equal(primitive, deserialized);
     }
 
+    [Fact]
+    public void CaseInsensitiveSessionKeys()
+    {
+        // Arrange
+        var key1 = _fixture.Create<string>();
+        var key2 = _fixture.Create<string>();
+
+        var options = new JsonSessionSerializerOptions
+        {
+            KeyComparer = StringComparer.OrdinalIgnoreCase,
+            KnownKeys =
+            {
+                { key1, typeof(Type1) },
+                { key2, typeof(int) },
+            }
+        };
+
+        // Act
+        var result1 = options.KnownKeys.ContainsKey(key1.ToUpperInvariant());
+        var result2 = options.KnownKeys.ContainsKey(key2);
+
+        // Assert
+        Assert.True(result1);
+        Assert.True(result2);
+    }
+
+    [Fact]
+    public void ChangeSessionKeysComparer()
+    {
+        // Arrange
+        var key1 = _fixture.Create<string>();
+        var key2 = _fixture.Create<string>();
+
+        var options = new JsonSessionSerializerOptions
+        {
+            KnownKeys =
+            {
+                { key1, typeof(Type1) },
+                { key2, typeof(int) },
+            }
+        };
+
+        // Act
+        var result1 = options.KnownKeys.ContainsKey(key1);
+        var result2 = options.KnownKeys.ContainsKey(key2);
+        var result3 = options.KnownKeys.ContainsKey(key2.ToUpperInvariant());
+
+        // Assert
+        Assert.True(result1);
+        Assert.True(result2);
+        Assert.False(result3);
+
+        // Re-arrange
+        options.KeyComparer = StringComparer.OrdinalIgnoreCase;
+
+        // Act
+        result1 = options.KnownKeys.ContainsKey(key1);
+        result2 = options.KnownKeys.ContainsKey(key2.ToUpperInvariant());
+
+        // Assert
+        Assert.True(result1);
+        Assert.True(result2);
+    }
+
     private sealed class Type1
     {
     }