Provide upgrade response details

src/libraries/System.Net.WebSockets.Client/ref/System.Net.WebSockets.Client.cs

@@ -4,13 +4,16 @@
 // Changes to this file must follow the https://aka.ms/api-review process.
 // ------------------------------------------------------------------------------
 
+
 namespace System.Net.WebSockets
 {
     public sealed partial class ClientWebSocket : System.Net.WebSockets.WebSocket
     {
         public ClientWebSocket() { }
         public override System.Net.WebSockets.WebSocketCloseStatus? CloseStatus { get { throw null; } }
         public override string? CloseStatusDescription { get { throw null; } }
+        public System.Net.HttpStatusCode HttpStatusCode { get { throw null; } }
+        public System.Collections.Generic.IReadOnlyDictionary<string, System.Collections.Generic.IEnumerable<string>>? HttpResponseHeaders { get { throw null; } set { } }
         public System.Net.WebSockets.ClientWebSocketOptions Options { get { throw null; } }
         public override System.Net.WebSockets.WebSocketState State { get { throw null; } }
         public override string? SubProtocol { get { throw null; } }
@@ -32,6 +35,8 @@ internal ClientWebSocketOptions() { }
         [System.Runtime.Versioning.UnsupportedOSPlatformAttribute("browser")]
         public System.Net.CookieContainer? Cookies { get { throw null; } set { } }
         [System.Runtime.Versioning.UnsupportedOSPlatformAttribute("browser")]
+        public bool CollectHttpResponseDetails { get { throw null; } set { } }
+        [System.Runtime.Versioning.UnsupportedOSPlatformAttribute("browser")]
         public System.Net.ICredentials? Credentials { get { throw null; } set { } }
         [System.Runtime.Versioning.UnsupportedOSPlatformAttribute("browser")]
         public System.TimeSpan KeepAliveInterval { get { throw null; } set { } }

src/libraries/System.Net.WebSockets.Client/src/System.Net.WebSockets.Client.csproj

@@ -9,6 +9,7 @@
     <Compile Include="System\Net\WebSockets\ClientWebSocketOptions.cs" Condition="'$(TargetPlatformIdentifier)' != 'Browser'" />
     <Compile Include="$(CommonPath)System\Net\UriScheme.cs" Link="Common\System\Net\UriScheme.cs" />
     <Compile Include="$(CommonPath)System\Net\WebSockets\WebSocketValidate.cs" Link="Common\System\Net\WebSockets\WebSocketValidate.cs" />
+    <Compile Include="System\Net\WebSockets\HttpResponseHeadersReadOnlyCollection.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetPlatformIdentifier)' != 'Browser'">
     <Compile Include="System\Net\WebSockets\WebSocketHandle.Managed.cs" />

src/libraries/System.Net.WebSockets.Client/src/System/Net/WebSockets/BrowserWebSockets/ClientWebSocketOptions.cs

@@ -67,6 +67,13 @@ public System.Net.CookieContainer Cookies
             set => throw new PlatformNotSupportedException();
         }
 
+        [UnsupportedOSPlatform("browser")]
+        public bool CollectHttpResponseDetails
+        {
+            get => throw new PlatformNotSupportedException();
+            set => throw new PlatformNotSupportedException();
+        }
+
         #endregion HTTP Settings
 
         #region WebSocket Settings

src/libraries/System.Net.WebSockets.Client/src/System/Net/WebSockets/ClientWebSocket.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.Collections.Generic;
 using System.Diagnostics;
 using System.Threading;
 using System.Threading.Tasks;
@@ -50,6 +51,21 @@ public override WebSocketState State
             }
         }
 
+        public System.Net.HttpStatusCode HttpStatusCode => _innerWebSocket != null ? _innerWebSocket.HttpStatusCode : 0;
+
+        // setter to clean up when not needed anymore
+        public IReadOnlyDictionary<string, IEnumerable<string>>? HttpResponseHeaders
+        {
+            get => _innerWebSocket?.HttpResponseHeaders;
+            set
+            {
+                if (_innerWebSocket != null)
+                {
+                    _innerWebSocket.HttpResponseHeaders = value;
+                }
+            }
+        }
+
         public Task ConnectAsync(Uri uri, CancellationToken cancellationToken)
         {
             ArgumentNullException.ThrowIfNull(uri);

src/libraries/System.Net.WebSockets.Client/src/System/Net/WebSockets/ClientWebSocketOptions.cs

@@ -206,6 +206,9 @@ public void SetBuffer(int receiveBufferSize, int sendBufferSize, ArraySegment<by
             _buffer = buffer;
         }
 
+        [System.Runtime.Versioning.UnsupportedOSPlatformAttribute("browser")]
+        public bool CollectHttpResponseDetails { get; set; }
+
         #endregion WebSocket settings
 
         #region Helpers

src/libraries/System.Net.WebSockets.Client/src/System/Net/WebSockets/HttpResponseHeadersReadOnlyCollection.cs

@@ -0,0 +1,36 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Net.Http.Headers;
+
+namespace System.Net.WebSockets
+{
+    internal sealed class HttpResponseHeadersReadOnlyCollection : IReadOnlyDictionary<string, IEnumerable<string>>
+    {
+        private readonly IReadOnlyDictionary<string, HeaderStringValues> _headers;
+
+        public HttpResponseHeadersReadOnlyCollection(HttpResponseHeaders headers) => _headers = headers.NonValidated;
+
+        public IEnumerable<string> this[string key] => _headers[key];
+
+        public IEnumerable<string> Keys => _headers.Keys;
+
+        public IEnumerable<IEnumerable<string>> Values => (IEnumerable<IEnumerable<string>>)_headers.Values;
+
+        public int Count => _headers.Count;
+
+        public bool ContainsKey(string key) => _headers.ContainsKey(key);
+        public IEnumerator<KeyValuePair<string, IEnumerable<string>>> GetEnumerator() => (IEnumerator<KeyValuePair<string, IEnumerable<string>>>)_headers.GetEnumerator();
+        public bool TryGetValue(string key, [MaybeNullWhen(false)] out IEnumerable<string> value)
+        {
+            bool res = _headers.TryGetValue(key, out HeaderStringValues headerStringValues);
+            value = headerStringValues;
+            return res;
+        }
+
+        IEnumerator IEnumerable.GetEnumerator() => _headers.GetEnumerator();
+    }
+}

src/libraries/System.Net.WebSockets.Client/src/System/Net/WebSockets/WebSocketHandle.Browser.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.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -9,6 +10,9 @@ namespace System.Net.WebSockets
     internal sealed class WebSocketHandle
     {
         private WebSocketState _state = WebSocketState.Connecting;
+        public HttpStatusCode HttpStatusCode { get; set; }
+
+        public IReadOnlyDictionary<string, IEnumerable<string>>? HttpResponseHeaders { get; set; }
 
         public WebSocket? WebSocket { get; private set; }
         public WebSocketState State => WebSocket?.State ?? _state;

src/libraries/System.Net.WebSockets.Client/src/System/Net/WebSockets/WebSocketHandle.Managed.cs

@@ -27,6 +27,9 @@ internal sealed class WebSocketHandle
 
         public WebSocket? WebSocket { get; private set; }
         public WebSocketState State => WebSocket?.State ?? _state;
+        public HttpStatusCode HttpStatusCode { get; set; }
+
+        public IReadOnlyDictionary<string, IEnumerable<string>>? HttpResponseHeaders { get; set; }
 
         public static ClientWebSocketOptions CreateDefaultOptions() => new ClientWebSocketOptions() { Proxy = DefaultWebProxy.Instance };
 
@@ -47,6 +50,7 @@ public async Task ConnectAsync(Uri uri, CancellationToken cancellationToken, Cli
             HttpResponseMessage? response = null;
             SocketsHttpHandler? handler = null;
             bool disposeHandler = true;
+            bool disposeResponse = false;
             try
             {
                 var request = new HttpRequestMessage(HttpMethod.Get, uri);
@@ -226,7 +230,7 @@ public async Task ConnectAsync(Uri uri, CancellationToken cancellationToken, Cli
                 }
 
                 Abort();
-                response?.Dispose();
+                disposeResponse = true;
 
                 if (exc is WebSocketException ||
                     (exc is OperationCanceledException && cancellationToken.IsCancellationRequested))
@@ -238,6 +242,17 @@ public async Task ConnectAsync(Uri uri, CancellationToken cancellationToken, Cli
             }
             finally
             {
+                if (options.CollectHttpResponseDetails && response != null)
+                {
+                    HttpStatusCode = response.StatusCode;
+                    HttpResponseHeaders = new HttpResponseHeadersReadOnlyCollection(response.Headers);
+                }
+
+                if (disposeResponse)
+                {
+                    response?.Dispose();
+                }
+
                 // Disposing the handler will not affect any active stream wrapped in the WebSocket.
                 if (disposeHandler)
                 {

src/libraries/System.Net.WebSockets.Client/tests/ConnectTest.cs

@@ -313,5 +313,46 @@ await server.AcceptConnectionAsync(async connection =>
                 catch (IOException) { }
             }, new LoopbackServer.Options { WebSocketEndpoint = true });
         }
+
+        [ConditionalFact(nameof(WebSocketsSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/34690", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [SkipOnPlatform(TestPlatforms.Browser, "CollectHttpResponseDetails not supported on Browser")]
+        public async Task ConnectAsync_HttpResponseDetailsCollectedOnFailure()
+        {
+            await LoopbackServer.CreateClientAndServerAsync(async uri =>
+            {
+                using (var clientWebSocket = new ClientWebSocket())
+                using (var cts = new CancellationTokenSource(TimeOutMilliseconds))
+                {
+                    clientWebSocket.Options.CollectHttpResponseDetails = true;
+                    Task t = clientWebSocket.ConnectAsync(uri, cts.Token);
+                    await Assert.ThrowsAnyAsync<WebSocketException>(() => t);
+
+                    Assert.Equal(HttpStatusCode.Unauthorized, clientWebSocket.HttpStatusCode);
+                    Assert.NotEmpty(clientWebSocket.HttpResponseHeaders);
+                }
+            }, server => server.AcceptConnectionSendResponseAndCloseAsync(HttpStatusCode.Unauthorized), new LoopbackServer.Options { WebSocketEndpoint = true });
+        }
+
+        [ConditionalFact(nameof(WebSocketsSupported))]
+        [ActiveIssue("https://github.com/dotnet/runtime/issues/34690", TestPlatforms.Windows, TargetFrameworkMonikers.Netcoreapp, TestRuntimes.Mono)]
+        [SkipOnPlatform(TestPlatforms.Browser, "CollectHttpResponseDetails not supported on Browser")]
+        public async Task ConnectAsync_HttpResponseDetailsCollectedOnSuccess_CustomHeader()
+        {
+            await LoopbackServer.CreateClientAndServerAsync(async uri =>
+            {
+                using (var clientWebSocket = new ClientWebSocket())
+                using (var cts = new CancellationTokenSource(TimeOutMilliseconds))
+                {
+                    clientWebSocket.Options.CollectHttpResponseDetails = true;
+                    Task t = clientWebSocket.ConnectAsync(uri, cts.Token);
+                    await Assert.ThrowsAnyAsync<WebSocketException>(() => t);
+
+                    Assert.Equal(HttpStatusCode.SwitchingProtocols, clientWebSocket.HttpStatusCode);
+                    Assert.NotEmpty(clientWebSocket.HttpResponseHeaders);
+                    Assert.Contains("X-CustomHeader1", clientWebSocket.HttpResponseHeaders);
+                }
+            }, server => server.AcceptConnectionSendResponseAndCloseAsync(HttpStatusCode.SwitchingProtocols, "X-CustomHeader1:Value1"), new LoopbackServer.Options { WebSocketEndpoint = true });
+        }
     }
 }