Merging PathNormalizer Implementations

- Follow up on comment: #56805 (comment)
- Moving PathNormalizer from Shared\HttpSys to Shared\PathNormalizer, changing the namespace to AspNetCore.Internal
- Shares the code between HttpSys and Kestrel.Core
- Remaining Kestrel specific code renamed to PathDecoder
- Keeping the tests and benchmarks in Kestrel

Author: ladeak

src/Servers/IIS/IIS/src/Microsoft.AspNetCore.Server.IIS.csproj

@@ -21,6 +21,7 @@
     <Compile Include="$(SharedSourceRoot)TypeNameHelper\*.cs" />
     <Compile Include="$(SharedSourceRoot)Buffers.MemoryPool\**\*.cs" LinkBase="Shared\" />
     <Compile Include="$(SharedSourceRoot)HttpSys\**\*.cs" LinkBase="Shared\" />
+    <Compile Include="$(SharedSourceRoot)PathNormalizer\PathNormalizer.cs" LinkBase="Shared\RequestProcessing\" />
     <Compile Include="$(SharedSourceRoot)StackTrace\**\*.cs" LinkBase="Shared\" />
     <Compile Include="$(SharedSourceRoot)RazorViews\*.cs" LinkBase="Shared\" />
     <Compile Include="$(SharedSourceRoot)ErrorPage\*.cs" LinkBase="Shared\" />

src/Servers/Kestrel/Core/src/Internal/Http/Http1Connection.cs

@@ -416,7 +416,7 @@ private void ParseTarget(TargetOffsetPathLength targetPath, Span<byte> target)
             else
             {
                 var path = target[..pathLength];
-                Path = _parsedPath = PathNormalizer.DecodePath(path, targetPath.IsEncoded, RawTarget, queryLength);
+                Path = _parsedPath = PathDecoder.DecodePath(path, targetPath.IsEncoded, RawTarget, queryLength);
             }
         }
         catch (InvalidOperationException)

src/Servers/Kestrel/Core/src/Internal/Http/PathDecoder.cs

@@ -0,0 +1,47 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Text;
+using Microsoft.AspNetCore.Internal;
+using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure;
+
+namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
+
+internal static class PathDecoder
+{
+    public static string DecodePath(Span<byte> path, bool pathEncoded, string rawTarget, int queryLength)
+    {
+        int pathLength;
+        if (pathEncoded)
+        {
+            // URI was encoded, unescape and then parse as UTF-8
+            pathLength = UrlDecoder.DecodeInPlace(path, isFormEncoding: false);
+
+            // Removing dot segments must be done after unescaping. From RFC 3986:
+            //
+            // URI producing applications should percent-encode data octets that
+            // correspond to characters in the reserved set unless these characters
+            // are specifically allowed by the URI scheme to represent data in that
+            // component.  If a reserved character is found in a URI component and
+            // no delimiting role is known for that character, then it must be
+            // interpreted as representing the data octet corresponding to that
+            // character's encoding in US-ASCII.
+            //
+            // https://tools.ietf.org/html/rfc3986#section-2.2
+            pathLength = PathNormalizer.RemoveDotSegments(path.Slice(0, pathLength));
+
+            return Encoding.UTF8.GetString(path.Slice(0, pathLength));
+        }
+
+        pathLength = PathNormalizer.RemoveDotSegments(path);
+
+        if (path.Length == pathLength && queryLength == 0)
+        {
+            // If no decoding was required, no dot segments were removed and
+            // there is no query, the request path is the same as the raw target
+            return rawTarget;
+        }
+
+        return path.Slice(0, pathLength).GetAsciiStringNonNullCharacters();
+    }
+}

src/Servers/Kestrel/Core/src/Internal/Http/PathNormalizer.cs

@@ -435,7 +435,7 @@ private bool TryValidatePath(ReadOnlySpan<char> pathSegment)
                 pathBuffer[i] = (byte)ch;
             }
 
-            Path = PathNormalizer.DecodePath(pathBuffer, pathEncoded, RawTarget!, QueryString!.Length);
+            Path = PathDecoder.DecodePath(pathBuffer, pathEncoded, RawTarget!, QueryString!.Length);
 
             return true;
         }

src/Servers/Kestrel/Core/src/Internal/Http2/Http2Stream.cs

@@ -1166,7 +1166,7 @@ private bool TryValidatePath(ReadOnlySpan<char> pathSegment)
                 pathBuffer[i] = (byte)ch;
             }
 
-            Path = PathNormalizer.DecodePath(pathBuffer, pathEncoded, RawTarget!, QueryString!.Length);
+            Path = PathDecoder.DecodePath(pathBuffer, pathEncoded, RawTarget!, QueryString!.Length);
 
             return true;
         }

src/Servers/Kestrel/Core/src/Internal/Http3/Http3Stream.cs

@@ -22,6 +22,7 @@
     <Compile Include="$(SharedSourceRoot)CertificateGeneration\**\*.cs" />
     <Compile Include="$(SharedSourceRoot)ValueTaskExtensions\**\*.cs" />
     <Compile Include="$(SharedSourceRoot)UrlDecoder\**\*.cs" />
+    <Compile Include="$(SharedSourceRoot)PathNormalizer\**\*.cs" LinkBase="Shared\" />
     <Compile Include="$(SharedSourceRoot)InternalHeaderNames.cs" Link="Shared\InternalHeaderNames.cs"/>
     <Compile Include="$(SharedSourceRoot)Buffers\**\*.cs" LinkBase="Internal\Infrastructure\PipeWriterHelpers" />
     <Compile Include="$(SharedSourceRoot)runtime\*.cs" Link="Shared\runtime\%(Filename)%(Extension)" />

src/Servers/Kestrel/Core/src/Microsoft.AspNetCore.Server.Kestrel.Core.csproj

@@ -1,10 +1,8 @@
 // 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.Text;
-using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
-using Xunit;
+using Microsoft.AspNetCore.Internal;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests;
 

src/Servers/Kestrel/Core/test/PathNormalizerTests.cs

@@ -3,7 +3,7 @@
 
 using System.Text;
 using BenchmarkDotNet.Attributes;
-using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
+using Microsoft.AspNetCore.Internal;
 
 namespace Microsoft.AspNetCore.Server.Kestrel.Microbenchmarks;
 

src/Servers/Kestrel/perf/Microbenchmarks/DotSegmentRemovalBenchmark.cs

@@ -3,6 +3,7 @@
 
 using System.Diagnostics;
 using System.Text;
+using Microsoft.AspNetCore.Internal;
 
 namespace Microsoft.AspNetCore.HttpSys.Internal;