Implement res:// protocol for WebView, MIME type handling.

Robust.Client.WebView/Cef/WebViewManagerCef.Mime.cs

@@ -0,0 +1,75 @@
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using Robust.Shared.Utility;
+
+namespace Robust.Client.WebView.Cef;
+
+internal sealed partial class WebViewManagerCef
+{
+    // Loosely based on:
+    // https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types
+    private readonly Dictionary<string, string> _resourceMimeTypes = new()
+    {
+        { "aac", "audio/aac" },
+        { "avif", "image/avif" },
+        { "avi", "video/x-msvideo" },
+        { "bmp", "image/bmp" },
+        { "css", "text/css" },
+        { "gif", "image/gif" },
+        { "htm", "text/html" },
+        { "html", "text/html" },
+        { "ico", "image/vnd.microsoft.icon" },
+        { "jpeg", "image/jpeg" },
+        { "jpg", "image/jpeg" },
+        { "js", "text/javascript" },
+        { "json", "application/json" },
+        { "jsonld", "application/ld+json" },
+        { "midi", "audio/midi" },
+        { "mid", "audio/midi" },
+        { "mjs", "text/javascript" },
+        { "mp3", "audio/mpeg" },
+        { "mp4", "video/mp4" },
+        { "mpeg", "video/mpeg" },
+        { "oga", "audio/ogg" },
+        { "ogg", "audio/ogg" },
+        { "ogv", "video/ogg" },
+        { "ogx", "application/ogg" },
+        { "opus", "audio/opus" },
+        { "otf", "font/otf" },
+        { "png", "image/png" },
+        { "pdf", "application/pdf" },
+        { "svg", "image/svg+xml" },
+        { "tiff", "image/tiff" },
+        { "tif", "image/tiff" },
+        { "ts", "video/mp2t" },
+        { "ttf", "font/ttf" },
+        { "txt", "text/plain" },
+        { "wav", "audio/wav" },
+        { "weba", "audio/webm" },
+        { "webm", "video/webm" },
+        { "webp", "image/webp" },
+        { "woff", "font/woff" },
+        { "woff2", "font/woff2" },
+        { "xhtml", "application/xhtml+xml" },
+        { "xml", "application/xml" },
+        { "zip", "application/zip" },
+    };
+
+    public void SetResourceMimeType(string extension, string mimeType)
+    {
+        DebugTools.Assert(!extension.StartsWith("."), "SetResourceMimeType extension must not include starting dot.");
+
+        lock (_resourceMimeTypes)
+        {
+            _resourceMimeTypes[extension] = mimeType;
+        }
+    }
+
+    public bool TryGetResourceMimeType(string extension, [NotNullWhen(true)] out string? mimeType)
+    {
+        lock (_resourceMimeTypes)
+        {
+            return _resourceMimeTypes.TryGetValue(extension, out mimeType);
+        }
+    }
+}

Robust.Client.WebView/Cef/WebViewManagerCef.cs

@@ -2,7 +2,9 @@ using System;
 using System.IO;
 using System.Net;
 using System.Reflection;
+using System.Text;
 using Robust.Client.Console;
+using Robust.Shared.Configuration;
 using Robust.Shared.ContentPack;
 using Robust.Shared.IoC;
 using Robust.Shared.Localization;
@@ -23,6 +25,7 @@ namespace Robust.Client.WebView.Cef
         [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
         [Dependency] private readonly IResourceManagerInternal _resourceManager = default!;
         [Dependency] private readonly IClientConsoleHost _consoleHost = default!;
+        [Dependency] private readonly IConfigurationManager _cfg = default!;
 
         public void Initialize()
         {
@@ -76,6 +79,12 @@ namespace Robust.Client.WebView.Cef
             // TODO CEF: After this point, debugging breaks. No, literally. My client crashes but ONLY with the debugger.
             // I have tried using the DEBUG and RELEASE versions of libcef.so, stripped or non-stripped...
             // And nothing seemed to work. Odd.
+
+            if (_cfg.GetCVar(WCVars.WebResProtocol))
+            {
+                var handler = new ResourceSchemeFactoryHandler(this, _resourceManager, Logger.GetSawmill("web.res"));
+                CefRuntime.RegisterSchemeHandlerFactory("res", "", handler);
+            }
         }
 
         private static string? LocateCefResources()
@@ -119,5 +128,48 @@ namespace Robust.Client.WebView.Cef
         {
             CefRuntime.Shutdown();
         }
+
+        private sealed class ResourceSchemeFactoryHandler : CefSchemeHandlerFactory
+        {
+            private readonly WebViewManagerCef _parent;
+            private readonly IResourceManager _resourceManager;
+            private readonly ISawmill _sawmill;
+
+            public ResourceSchemeFactoryHandler(
+                WebViewManagerCef parent,
+                IResourceManager resourceManager,
+                ISawmill sawmill)
+            {
+                _parent = parent;
+                _resourceManager = resourceManager;
+                _sawmill = sawmill;
+            }
+
+            protected override CefResourceHandler Create(
+                CefBrowser browser,
+                CefFrame frame,
+                string schemeName,
+                CefRequest request)
+            {
+                var uri = new Uri(request.Url);
+
+                _sawmill.Debug($"HANDLING: {request.Url}");
+
+                var resourcePath = new ResourcePath(uri.AbsolutePath);
+                if (_resourceManager.TryContentFileRead(resourcePath, out var stream))
+                {
+                    if (!_parent.TryGetResourceMimeType(resourcePath.Extension, out var mime))
+                        mime = "application/octet-stream";
+
+                    return new RequestResultStream(stream, mime, HttpStatusCode.OK).MakeHandler();
+                }
+
+                var notFoundStream = new MemoryStream();
+                notFoundStream.Write(Encoding.UTF8.GetBytes("Not found"));
+                notFoundStream.Position = 0;
+
+                return new RequestResultStream(notFoundStream, "text/plain", HttpStatusCode.NotFound).MakeHandler();
+            }
+        }
     }
 }

Robust.Client.WebView/Headless/WebViewManagerHeadless.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
 using Robust.Client.Graphics;
 using Robust.Client.UserInterface;
 
@@ -11,6 +12,17 @@ namespace Robust.Client.WebView.Headless
             return new WebViewWindowDummy();
         }
 
+        public void SetResourceMimeType(string extension, string mimeType)
+        {
+            // Nop
+        }
+
+        public bool TryGetResourceMimeType(string extension, [NotNullWhen(true)] out string? mimeType)
+        {
+            mimeType = null;
+            return false;
+        }
+
         public IWebViewControlImpl MakeControlImpl(WebViewControl owner)
         {
             return new WebViewControlImplDummy();

Robust.Client.WebView/IWebViewManager.cs

@@ -1,7 +1,40 @@
-namespace Robust.Client.WebView
+using System.Diagnostics.CodeAnalysis;
+
+namespace Robust.Client.WebView
 {
     public interface IWebViewManager
     {
         IWebViewWindow CreateBrowserWindow(BrowserWindowCreateParameters createParams);
+
+        /// <summary>
+        /// Overrides file extension -> mime type mappings for the <c>res://</c> protocol.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// The built-in <c>res://</c> protocol needs to guess MIME types to report to CEF when resolving files.
+        /// A limited set of extensions have pre-set MIME types in the engine.
+        /// This method allows you to replace or add entries if need be.
+        /// </para>
+        /// <para>
+        /// This method is thread safe.
+        /// </para>
+        /// </remarks>
+        /// <param name="extension">
+        /// The extension to specify the MIME type for.
+        /// The argument must not include the starting "." of the file extension.
+        /// </param>
+        /// <param name="mimeType">The mime type for this file extension.</param>
+        /// <seealso cref="TryGetResourceMimeType"/>
+        void SetResourceMimeType(string extension, string mimeType);
+
+        /// <summary>
+        /// Tries to resolve an entry from the <see cref="SetResourceMimeType"/> list.
+        /// </summary>
+        /// <remarks>
+        /// <para>
+        /// This method is thread safe.
+        /// </para>
+        /// </remarks>
+        bool TryGetResourceMimeType(string extension, [NotNullWhen(true)] out string? mimeType);
     }
 }

Robust.Client.WebView/WCVars.cs

@@ -0,0 +1,17 @@
+using Robust.Shared.Configuration;
+
+namespace Robust.Client.WebView;
+
+// ReSharper disable once InconsistentNaming
+/// <summary>
+/// CVars for <c>Robust.Client.WebView</c>
+/// </summary>
+[CVarDefs]
+public static class WCVars
+{
+    /// <summary>
+    /// Enable the <c>res://</c> protocol inside WebView browsers, allowing access to the Robust resources.
+    /// </summary>
+    public static readonly CVarDef<bool> WebResProtocol =
+        CVarDef.Create("web.res_protocol", true, CVar.CLIENTONLY);
+}

Robust.Client.WebView/WebViewManager.cs

@@ -1,7 +1,9 @@
-using Robust.Client.WebView;
+using System.Diagnostics.CodeAnalysis;
+using Robust.Client.WebView;
 using Robust.Client.WebView.Cef;
 using Robust.Client.WebView.Headless;
 using Robust.Client.WebViewHook;
+using Robust.Shared.Configuration;
 using Robust.Shared.IoC;
 using Robust.Shared.Utility;
 
@@ -17,6 +19,9 @@ namespace Robust.Client.WebView
         {
             DebugTools.Assert(_impl == null, "WebViewManager has already been initialized!");
 
+            var cfg = IoCManager.Resolve<IConfigurationManagerInternal>();
+            cfg.LoadCVarsFromAssembly(typeof(WebViewManager).Assembly);
+
             IoCManager.RegisterInstance<IWebViewManager>(this);
             IoCManager.RegisterInstance<IWebViewManagerInternal>(this);
 
@@ -49,6 +54,20 @@ namespace Robust.Client.WebView
             return _impl!.CreateBrowserWindow(createParams);
         }
 
+        public void SetResourceMimeType(string extension, string mimeType)
+        {
+            DebugTools.Assert(_impl != null, "WebViewManager has not yet been initialized!");
+
+            _impl!.SetResourceMimeType(extension, mimeType);
+        }
+
+        public bool TryGetResourceMimeType(string extension, [NotNullWhen(true)] out string? mimeType)
+        {
+            DebugTools.Assert(_impl != null, "WebViewManager has not yet been initialized!");
+
+            return _impl!.TryGetResourceMimeType(extension, out mimeType);
+        }
+
         public IWebViewControlImpl MakeControlImpl(WebViewControl owner)
         {
             DebugTools.Assert(_impl != null, "WebViewManager has not yet been initialized!");