Fix WebView header APIs and behavior

src/Components/WebView/Platforms/WebView2/src/WebView2WebViewManager.cs

@@ -2,6 +2,8 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.Extensions.FileProviders;
 using Microsoft.Web.WebView2.Core;
@@ -73,7 +75,8 @@ private async Task InitializeWebView2()
 
                 if (TryGetResponseContent(eventArgs.Request.Uri, allowFallbackOnHostPage, out var statusCode, out var statusMessage, out var content, out var headers))
                 {
-                    eventArgs.Response = environment.CreateWebResourceResponse(content, statusCode, statusMessage, headers);
+                    var headerString = GetHeaderString(headers);
+                    eventArgs.Response = environment.CreateWebResourceResponse(content, statusCode, statusMessage, headerString);
                 }
             };
 
@@ -94,6 +97,9 @@ await _webview.CoreWebView2.AddScriptToExecuteOnDocumentCreatedAsync(@"
                 => MessageReceived(new Uri(eventArgs.Source), eventArgs.TryGetWebMessageAsString());
         }
 
+        private static string GetHeaderString(IDictionary<string, string> headers) =>
+            string.Join(Environment.NewLine, headers.Select(kvp => $"{kvp.Key}: {kvp.Value}"));
+
         private void ApplyDefaultWebViewSettings()
         {
             // Desktop applications typically don't want the default web browser context menu

src/Components/WebView/Samples/BlazorWpfApp/Pages/Index.razor

@@ -1,6 +1,6 @@
 @page "/"
 @using WebviewAppShared
-// NOTE: The full namespace is included here to work around this bug: https://github.com/dotnet/aspnetcore/issues/30851
+@* NOTE: The full namespace is included here to work around this bug: https://github.com/dotnet/aspnetcore/issues/30851 *@
 @inject BlazorWpfApp.AppState AppState
 
 <h3>Hello, world!</h3>

src/Components/WebView/WebView/src/PublicAPI.Unshipped.txt

@@ -6,7 +6,7 @@ Microsoft.AspNetCore.Components.WebView.WebViewManager.Dispose() -> void
 Microsoft.AspNetCore.Components.WebView.WebViewManager.MessageReceived(System.Uri! sourceUri, string! message) -> void
 Microsoft.AspNetCore.Components.WebView.WebViewManager.Navigate(string! url) -> void
 Microsoft.AspNetCore.Components.WebView.WebViewManager.RemoveRootComponentAsync(string! selector) -> System.Threading.Tasks.Task!
-Microsoft.AspNetCore.Components.WebView.WebViewManager.TryGetResponseContent(string! uri, bool allowFallbackOnHostPage, out int statusCode, out string! statusMessage, out System.IO.Stream! content, out string! headers) -> bool
+Microsoft.AspNetCore.Components.WebView.WebViewManager.TryGetResponseContent(string! uri, bool allowFallbackOnHostPage, out int statusCode, out string! statusMessage, out System.IO.Stream! content, out System.Collections.Generic.IDictionary<string!, string!>! headers) -> bool
 Microsoft.AspNetCore.Components.WebView.WebViewManager.WebViewManager(System.IServiceProvider! provider, Microsoft.AspNetCore.Components.Dispatcher! dispatcher, System.Uri! appBaseUri, Microsoft.Extensions.FileProviders.IFileProvider! fileProvider, string! hostPageRelativePath) -> void
 Microsoft.Extensions.DependencyInjection.ComponentsWebViewServiceCollectionExtensions
 abstract Microsoft.AspNetCore.Components.WebView.WebViewManager.NavigateCore(System.Uri! absoluteUri) -> void

src/Components/WebView/WebView/src/StaticContentProvider.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Text;
 using Microsoft.Extensions.FileProviders;
@@ -24,7 +25,7 @@ public StaticContentProvider(IFileProvider fileProvider, Uri appBaseUri, string
             _hostPageRelativePath = hostPageRelativePath ?? throw new ArgumentNullException(nameof(hostPageRelativePath));
         }
 
-        public bool TryGetResponseContent(string requestUri, bool allowFallbackOnHostPage, out int statusCode, out string statusMessage, out Stream content, out string headers)
+        public bool TryGetResponseContent(string requestUri, bool allowFallbackOnHostPage, out int statusCode, out string statusMessage, out Stream content, out IDictionary<string, string> headers)
         {
             var fileUri = new Uri(requestUri);
             if (_appBaseUri.IsBaseOf(fileUri))
@@ -75,7 +76,7 @@ private bool TryGetFromFileProvider(string relativePath, out Stream content, out
                 if (fileInfo.Exists)
                 {
                     content = fileInfo.CreateReadStream();
-                    contentType = GetResponseContentTypeOrDefault(fileInfo.PhysicalPath);
+                    contentType = GetResponseContentTypeOrDefault(fileInfo.Name);
                     return true;
                 }
             }
@@ -107,7 +108,11 @@ private static string GetResponseContentTypeOrDefault(string path)
             ? matchedContentType
             : "application/octet-stream";
 
-        private static string GetResponseHeaders(string contentType)
-            => $"Content-Type: {contentType}{Environment.NewLine}Cache-Control: no-cache, max-age=0, must-revalidate, no-store";
+        private static IDictionary<string, string> GetResponseHeaders(string contentType)
+            => new Dictionary<string, string>()
+            {
+                { "Content-Type", contentType },
+                { "Cache-Control", "no-cache, max-age=0, must-revalidate, no-store" },
+            };
     }
 }

src/Components/WebView/WebView/src/WebViewManager.cs

@@ -168,7 +168,7 @@ protected void MessageReceived(Uri sourceUri, string message)
         /// <param name="content">The response content</param>
         /// <param name="headers">The response headers</param>
         /// <returns><c>true</c> if the response can be provided; <c>false</c> otherwise.</returns>
-        protected bool TryGetResponseContent(string uri, bool allowFallbackOnHostPage, out int statusCode, out string statusMessage, out Stream content, out string headers)
+        protected bool TryGetResponseContent(string uri, bool allowFallbackOnHostPage, out int statusCode, out string statusMessage, out Stream content, out IDictionary<string, string> headers)
             => _staticContentProvider.TryGetResponseContent(uri, allowFallbackOnHostPage, out statusCode, out statusMessage, out content, out headers);
 
         internal async Task AttachToPageAsync(string baseUrl, string startUrl)

src/Components/WebView/WebView/test/StaticContentProviderTests.cs

@@ -0,0 +1,140 @@
+// 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.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using Microsoft.Extensions.FileProviders;
+using Microsoft.Extensions.Primitives;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Components.WebView
+{
+    public class StaticContentProviderTests
+    {
+        [Fact]
+        public void TryGetResponseContentReturnsCorrectContentTypeForNonPhysicalFile()
+        {
+            // Arrange
+            const string cssFilePath = "folder/file.css";
+            const string cssFileContent = "this is css";
+            var inMemoryFileProvider = new InMemoryFileProvider(
+                new Dictionary<string, string>
+                {
+                    { cssFilePath, cssFileContent },
+                });
+            var appBase = "fake://0.0.0.0/";
+            var scp = new StaticContentProvider(inMemoryFileProvider, new Uri(appBase), "fakehost.html");
+
+            // Act
+            Assert.True(scp.TryGetResponseContent(
+                requestUri: appBase + cssFilePath,
+                allowFallbackOnHostPage: false,
+                out var statusCode,
+                out var statusMessage,
+                out var content,
+                out var headers));
+
+            // Assert
+            var contentString = new StreamReader(content).ReadToEnd();
+            Assert.Equal(200, statusCode);
+            Assert.Equal("OK", statusMessage);
+            Assert.Equal("this is css", contentString);
+            Assert.True(headers.TryGetValue("Content-Type", out var contentTypeValue));
+            Assert.Equal("text/css", contentTypeValue);
+        }
+
+        private sealed class InMemoryFileProvider : IFileProvider
+        {
+            public InMemoryFileProvider(IDictionary<string, string> filePathsAndContents)
+            {
+                if (filePathsAndContents is null)
+                {
+                    throw new ArgumentNullException(nameof(filePathsAndContents));
+                }
+
+                FilePathsAndContents = filePathsAndContents;
+            }
+
+            public IDictionary<string, string> FilePathsAndContents { get; }
+
+            public IDirectoryContents GetDirectoryContents(string subpath)
+            {
+                return new InMemoryDirectoryContents(this, subpath);
+            }
+
+            public IFileInfo GetFileInfo(string subpath)
+            {
+                return FilePathsAndContents
+                    .Where(kvp => kvp.Key == subpath)
+                    .Select(x => new InMemoryFileInfo(x.Key, x.Value))
+                    .Single();
+            }
+
+            public IChangeToken Watch(string filter)
+            {
+                return null;
+            }
+
+            private sealed class InMemoryDirectoryContents : IDirectoryContents
+            {
+                private readonly InMemoryFileProvider _inMemoryFileProvider;
+                private readonly string _subPath;
+
+                public InMemoryDirectoryContents(InMemoryFileProvider inMemoryFileProvider, string subPath)
+                {
+                    _inMemoryFileProvider = inMemoryFileProvider ?? throw new ArgumentNullException(nameof(inMemoryFileProvider));
+                    _subPath = subPath ?? throw new ArgumentNullException(nameof(inMemoryFileProvider));
+                }
+
+                public bool Exists => true;
+
+                public IEnumerator<IFileInfo> GetEnumerator()
+                {
+                    return
+                        _inMemoryFileProvider
+                            .FilePathsAndContents
+                            .Where(kvp => kvp.Key.StartsWith(_subPath, StringComparison.Ordinal))
+                            .Select(x => new InMemoryFileInfo(x.Key, x.Value))
+                            .GetEnumerator();
+                }
+
+                System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
+                {
+                    return GetEnumerator();
+                }
+            }
+
+            private sealed class InMemoryFileInfo : IFileInfo
+            {
+                private readonly string _filePath;
+                private readonly string _fileContents;
+
+                public InMemoryFileInfo(string filePath, string fileContents)
+                {
+                    _filePath = filePath;
+                    _fileContents = fileContents;
+                }
+
+                public bool Exists => true;
+
+                public long Length => _fileContents.Length;
+
+                public string PhysicalPath => null;
+
+                public string Name => Path.GetFileName(_filePath);
+
+                public DateTimeOffset LastModified => DateTimeOffset.Now;
+
+                public bool IsDirectory => false;
+
+                public Stream CreateReadStream()
+                {
+                    return new MemoryStream(Encoding.UTF8.GetBytes(_fileContents));
+                }
+            }
+        }
+    }
+}