Add options to configure case sensitivity of request paths

src/Microsoft.AspNetCore.ResponseCaching/ResponseCachingContext.cs

@@ -153,7 +153,7 @@ namespace Microsoft.AspNetCore.ResponseCaching
                 builder
                     .Append(request.Method.ToUpperInvariant())
                     .Append(KeyDelimiter)
-                    .Append(request.Path.Value.ToUpperInvariant());
+                    .Append(_options.CaseSensitivePaths ? request.Path.Value : request.Path.Value.ToUpperInvariant());
 
                 // Vary by headers
                 if (varyBy?.Headers.Count > 0)

src/Microsoft.AspNetCore.ResponseCaching/ResponseCachingOptions.cs

@@ -9,10 +9,15 @@ namespace Microsoft.AspNetCore.Builder
     public class ResponseCachingOptions
     {
         /// <summary>
-        /// The largest cacheable size for the response body in bytes.
+        /// The largest cacheable size for the response body in bytes. The default is set to 1 MB.
         /// </summary>
         public long MaximumCachedBodySize { get; set; } = 1024 * 1024;
 
+        /// <summary>
+        /// <c>true</c> if request paths are case-sensitive; otherwise <c>false</c>. The default is to treat paths as case-insensitive.
+        /// </summary>
+        public bool CaseSensitivePaths { get; set; } = false;
+
         /// <summary>
         /// For testing purposes only.
         /// </summary>

test/Microsoft.AspNetCore.ResponseCaching.Tests/ResponseCachingContextTests.cs

@@ -280,6 +280,34 @@ namespace Microsoft.AspNetCore.ResponseCaching.Tests
             }));
         }
 
+        [Fact]
+        public void CreateCacheKey_CaseInsensitivePath_NormalizesPath()
+        {
+            var httpContext = new DefaultHttpContext();
+            httpContext.Request.Method = "GET";
+            httpContext.Request.Path = "/Path";
+            var context = CreateTestContext(httpContext, new ResponseCachingOptions()
+            {
+                CaseSensitivePaths = false
+            });
+
+            Assert.Equal($"GET{KeyDelimiter}/PATH", context.CreateCacheKey());
+        }
+
+        [Fact]
+        public void CreateCacheKey_CaseSensitivePath_PreservesPathCase()
+        {
+            var httpContext = new DefaultHttpContext();
+            httpContext.Request.Method = "GET";
+            httpContext.Request.Path = "/Path";
+            var context = CreateTestContext(httpContext, new ResponseCachingOptions()
+            {
+                CaseSensitivePaths = true
+            });
+
+            Assert.Equal($"GET{KeyDelimiter}/Path", context.CreateCacheKey());
+        }
+
         [Fact]
         public void ResponseIsCacheable_NoPublic_NotAllowed()
         {
@@ -832,6 +860,16 @@ namespace Microsoft.AspNetCore.ResponseCaching.Tests
         {
             return CreateTestContext(
                 httpContext,
+                new ResponseCachingOptions(),
+                new NoopCacheKeyModifier(),
+                new NoopCacheabilityValidator());
+        }
+
+        private static ResponseCachingContext CreateTestContext(HttpContext httpContext, ResponseCachingOptions options)
+        {
+            return CreateTestContext(
+                httpContext,
+                options,
                 new NoopCacheKeyModifier(),
                 new NoopCacheabilityValidator());
         }
@@ -840,6 +878,7 @@ namespace Microsoft.AspNetCore.ResponseCaching.Tests
         {
             return CreateTestContext(
                 httpContext,
+                new ResponseCachingOptions(),
                 cacheKeyModifier,
                 new NoopCacheabilityValidator());
         }
@@ -848,19 +887,21 @@ namespace Microsoft.AspNetCore.ResponseCaching.Tests
         {
             return CreateTestContext(
                 httpContext,
+                new ResponseCachingOptions(),
                 new NoopCacheKeyModifier(),
                 cacheabilityValidator);
         }
 
         private static ResponseCachingContext CreateTestContext(
             HttpContext httpContext,
+            ResponseCachingOptions options,
             IResponseCachingCacheKeyModifier cacheKeyModifier,
             IResponseCachingCacheabilityValidator cacheabilityValidator)
         {
             return new ResponseCachingContext(
                 httpContext,
                 new TestResponseCache(),
-                new ResponseCachingOptions(),
+                options,
                 new DefaultObjectPool<StringBuilder>(new StringBuilderPooledObjectPolicy()),
                 cacheabilityValidator,
                 cacheKeyModifier);