Add support for fetchpriority attribute to LinkResource

src/Framework/Framework/ResourceManagement/LinkResourceBase.cs

@@ -33,6 +33,8 @@ public abstract class LinkResourceBase : ResourceBase, ILinkResource
         public bool VerifyResourceIntegrity { get; set; } = true;
         public string? IntegrityHash { get; set; }
 
+        public ResourceFetchPriority FetchPriority { get; set; } = ResourceFetchPriority.Auto;
+
         public LinkResourceBase(ResourceRenderPosition renderPosition, string mimeType, IResourceLocation location) : base(renderPosition)
         {
             this.Location = location;
@@ -101,7 +103,7 @@ protected string GetLoadingScript(string javascriptCondition, string script) =>
     script.text = originalScript.text;
     script.id = originalScript.id;
     document.head.appendChild(script);
-}}";
+}}".Replace("\r\n", "\n");
 
         protected string RenderLinkToString(IResourceLocation location, IDotvvmRequestContext context, string resourceName)
         {
@@ -146,6 +148,13 @@ protected void AddSrcAndIntegrity(IHtmlWriter writer, IDotvvmRequestContext cont
                 AddIntegrityAttribute(writer, context, url);
             }
         }
+
+        protected void AddFetchPriority(IHtmlWriter writer, IResourceLocation location, ResourceFetchPriority fetchPriority)
+        {
+            // add fetchpriority only to the primary location, not to fallbacks
+            if (location == (object)Location && fetchPriority != ResourceFetchPriority.Auto)
+                writer.AddAttribute("fetchpriority", fetchPriority == ResourceFetchPriority.High ? "high" : "low");
+        }
     }
 
     public class ResourceLocationFallback

src/Framework/Framework/ResourceManagement/ResourceFetchPriority.cs

@@ -0,0 +1,9 @@
+namespace DotVVM.Framework.ResourceManagement
+{
+    public enum ResourceFetchPriority
+    {
+        Auto,
+        High,
+        Low
+    }
+}

src/Framework/Framework/ResourceManagement/ResourceRepositoryExtensions.cs

@@ -11,11 +11,13 @@ public static StylesheetResource RegisterStylesheet(
             string name,
             IResourceLocation location,
             string[]? dependencies = null,
-            string? integrityHash = null)
+            string? integrityHash = null,
+            ResourceFetchPriority fetchPriority = ResourceFetchPriority.Auto)
         {
             var r = new StylesheetResource(location) {
                 Dependencies = dependencies ?? Array.Empty<string>(),
-                IntegrityHash = integrityHash
+                IntegrityHash = integrityHash,
+                FetchPriority = fetchPriority
             };
             repo.Register(name, r);
             return r;
@@ -28,19 +30,21 @@ public static StylesheetResource RegisterStylesheetFile(
             this DotvvmResourceRepository repo,
             string name,
             string filePath,
-            string[]? dependencies = null) =>
-            repo.RegisterStylesheet(name, new FileResourceLocation(filePath), dependencies);
+            string[]? dependencies = null,
+            ResourceFetchPriority fetchPriority = ResourceFetchPriority.Auto) =>
+            repo.RegisterStylesheet(name, new FileResourceLocation(filePath), dependencies, null, fetchPriority);
 
         /// <summary> Registers a <see cref="StylesheetResource" /> with the specified URL.
-        /// If the URL is local, consider using the <see cref="RegisterStylesheetFile(DotvvmResourceRepository, string, string, string[])" /> method. </summary>
+        /// If the URL is local, consider using the <see cref="RegisterStylesheetFile(DotvvmResourceRepository, string, string, string[], ResourceFetchPriority)" /> method. </summary>
         /// <param name="integrityHash"> is a hash of the served file, it's highly recommended to set it when the resource is from a 3rd party domain. See https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity for more information. </param>
         public static StylesheetResource RegisterStylesheetUrl(
             this DotvvmResourceRepository repo,
             string name,
             string url,
             string? integrityHash,
-            string[]? dependencies = null) =>
-            repo.RegisterStylesheet(name, new UrlResourceLocation(url), dependencies, integrityHash);
+            string[]? dependencies = null,
+            ResourceFetchPriority fetchPriority = ResourceFetchPriority.Auto) =>
+            repo.RegisterStylesheet(name, new UrlResourceLocation(url), dependencies, integrityHash, fetchPriority);
 
         /// <summary> Registers a <see cref="ScriptResource" /> (a Javascript resource) with the specified name, location and dependencies.
         /// <paramref name="integrityHash"/> does not have to be used when location is local. </summary>
@@ -51,13 +55,15 @@ public static LinkResourceBase RegisterScript(
             bool defer = true,
             bool module = false,
             string[]? dependencies = null,
-            string? integrityHash = null)
+            string? integrityHash = null,
+            ResourceFetchPriority fetchPriority = ResourceFetchPriority.Auto)
         {
             if (!defer && module)   
                 throw new ArgumentException("<script type='module'> always deferred, please do not specify defer: false", nameof(defer));
             LinkResourceBase r = module ? new ScriptModuleResource(location) : new ScriptResource(location, defer);
             r.Dependencies = dependencies ?? Array.Empty<string>();
             r.IntegrityHash = integrityHash;
+            r.FetchPriority = fetchPriority;
             repo.Register(name, r);
             return r;
         }
@@ -71,8 +77,9 @@ public static LinkResourceBase RegisterScriptFile(
             string filePath,
             bool defer = true,
             bool module = false,
-            string[]? dependencies = null) =>
-            repo.RegisterScript(name, new FileResourceLocation(filePath), defer, module, dependencies);
+            string[]? dependencies = null,
+            ResourceFetchPriority fetchPriority = ResourceFetchPriority.Auto) =>
+            repo.RegisterScript(name, new FileResourceLocation(filePath), defer, module, dependencies, null, fetchPriority);
 
         /// <summary> Registers a <see cref="ScriptModuleResource" /> from the specified file.
         /// The file can be anywhere in the filesystem, it does not have to be in the wwwroot folder.
@@ -81,8 +88,9 @@ public static LinkResourceBase RegisterScriptModuleFile(
             this DotvvmResourceRepository repo,
             string name,
             string filePath,
-            string[]? dependencies = null) =>
-            repo.RegisterScript(name, new FileResourceLocation(filePath), defer: true, module: true, dependencies);
+            string[]? dependencies = null,
+            ResourceFetchPriority fetchPriority = ResourceFetchPriority.Auto) =>
+            repo.RegisterScript(name, new FileResourceLocation(filePath), defer: true, module: true, dependencies, fetchPriority: fetchPriority);
 
         /// <summary> Registers a <see cref="ScriptModuleResource" /> from the specified file.
         /// The file can be anywhere in the filesystem, it does not have to be in the wwwroot folder.
@@ -97,7 +105,7 @@ public static LinkResourceBase RegisterScriptModuleFile(
             repo.RegisterScript(name, new FileResourceLocation(filePath), defer: true, module: true, dependencies);
 
         /// <summary> Registers a <see cref="ScriptResource" /> with the specified URL.
-        /// If the URL is local, consider using the <see cref="RegisterScriptFile(DotvvmResourceRepository, string, string, bool, bool, string[])" /> method. </summary>
+        /// If the URL is local, consider using the <see cref="RegisterScriptFile(DotvvmResourceRepository, string, string, bool, bool, string[], ResourceFetchPriority)" /> method. </summary>
         /// <param name="integrityHash"> is a hash of the served file, it's highly recommended to set it when the resource is from a 3rd party domain. See https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity for more information. </param>
         public static LinkResourceBase RegisterScriptUrl(
             this DotvvmResourceRepository repo,
@@ -106,19 +114,21 @@ public static LinkResourceBase RegisterScriptUrl(
             string? integrityHash,
             bool defer = true,
             bool module = false,
-            string[]? dependencies = null) =>
-            repo.RegisterScript(name, new UrlResourceLocation(url), defer, module, dependencies, integrityHash);
+            string[]? dependencies = null,
+            ResourceFetchPriority fetchPriority = ResourceFetchPriority.Auto) =>
+            repo.RegisterScript(name, new UrlResourceLocation(url), defer, module, dependencies, integrityHash, fetchPriority);
 
         /// <summary> Registers a <see cref="ScriptModuleResource" /> with the specified URL.
-        /// If the URL is local, consider using the <see cref="RegisterScriptFile(DotvvmResourceRepository, string, string, bool, bool, string[])" /> method. </summary>
+        /// If the URL is local, consider using the <see cref="RegisterScriptFile(DotvvmResourceRepository, string, string, bool, bool, string[], ResourceFetchPriority)" /> method. </summary>
         /// <param name="integrityHash"> is a hash of the served file, it's highly recommended to set it when the resource is from a 3rd party domain. See https://developer.mozilla.org/en-US/docs/Web/Security/Subresource_Integrity for more information. </param>
         public static LinkResourceBase RegisterScriptModuleUrl(
             this DotvvmResourceRepository repo,
             string name,
             string url,
             string? integrityHash,
             bool defer = true,
-            string[]? dependencies = null) =>
-            repo.RegisterScript(name, new UrlResourceLocation(url), defer, module: true, dependencies, integrityHash);
+            string[]? dependencies = null,
+            ResourceFetchPriority fetchPriority = ResourceFetchPriority.Auto) =>
+            repo.RegisterScript(name, new UrlResourceLocation(url), defer, module: true, dependencies, integrityHash, fetchPriority);
     }
 }

src/Framework/Framework/ResourceManagement/ScriptModuleResource.cs

@@ -35,6 +35,7 @@ public ScriptModuleResource(IResourceLocation location, bool defer)
         public override void RenderLink(IResourceLocation location, IHtmlWriter writer, IDotvvmRequestContext context, string resourceName)
         {
             AddSrcAndIntegrity(writer, context, location.GetUrl(context, resourceName), "src");
+            AddFetchPriority(writer, location, FetchPriority);
             writer.AddAttribute("type", "module");
             writer.RenderBeginTag("script");
             writer.RenderEndTag();

src/Framework/Framework/ResourceManagement/ScriptResource.cs

@@ -32,6 +32,8 @@ public override void RenderLink(IResourceLocation location, IHtmlWriter writer,
         private void RenderLink(IResourceLocation location, IHtmlWriter writer, IDotvvmRequestContext context, string resourceName, bool defer)
         {
             AddSrcAndIntegrity(writer, context, location.GetUrl(context, resourceName), "src");
+            AddFetchPriority(writer, location, FetchPriority);
+
             if (MimeType != "text/javascript") // this is the default, no need to write it
                 writer.AddAttribute("type", MimeType);
             if (defer)

src/Framework/Framework/ResourceManagement/StylesheetResource.cs

@@ -22,6 +22,7 @@ public StylesheetResource()
         public override void RenderLink(IResourceLocation location, IHtmlWriter writer, IDotvvmRequestContext context, string resourceName)
         {
             AddSrcAndIntegrity(writer, context, location.GetUrl(context, resourceName), "href");
+            AddFetchPriority(writer, location, FetchPriority);
             writer.AddAttribute("rel", "stylesheet");
             writer.AddAttribute("type", MimeType);
             writer.RenderSelfClosingTag("link");

src/Tests/Runtime/ResourceRenderTests.cs

@@ -0,0 +1,62 @@
+using System.IO;
+using CheckTestOutput;
+using DotVVM.Framework.Controls;
+using DotVVM.Framework.ResourceManagement;
+using DotVVM.Framework.Testing;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace DotVVM.Framework.Tests.Runtime
+{
+    [TestClass]
+    public class ResourceRenderTests
+    {
+        private readonly OutputChecker check = new OutputChecker("testoutputs");
+
+        private static string Render(LinkResourceBase resource, string resourceName = "r")
+        {
+            var context = DotvvmTestHelper.CreateContext();
+
+            using var text = new StringWriter();
+            var html = new HtmlWriter(text, context);
+            resource.Render(html, context, resourceName);
+            return text.ToString();
+        }
+
+        [TestMethod]
+        public void Script_WithFallback_OnlyPrimaryHasFetchPriority()
+        {
+            var res = new ScriptResource(new UrlResourceLocation("http://primary.example.com/app.js")) {
+                FetchPriority = ResourceFetchPriority.High,
+                LocationFallback = new ResourceLocationFallback(
+                    javascriptCondition: "true",
+                    new UrlResourceLocation("http://fallback.example.com/app.js")
+                )
+            };
+
+            var output = Render(res);
+            check.CheckString(output, fileExtension: "html");
+        }
+
+        [TestMethod]
+        public void ScriptModule_FetchPriority_High()
+        {
+            var res = new ScriptModuleResource(new UrlResourceLocation("http://example.com/module.js")) {
+                FetchPriority = ResourceFetchPriority.Low
+            };
+
+            var output = Render(res);
+            check.CheckString(output, fileExtension: "html");
+        }
+
+        [TestMethod]
+        public void Stylesheet_FetchPriority_High()
+        {
+            var res = new StylesheetResource(new UrlResourceLocation("http://example.com/style.css")) {
+                FetchPriority = ResourceFetchPriority.High
+            };
+
+            var output = Render(res);
+            check.CheckString(output, fileExtension: "html");
+        }
+    }
+}

src/Tests/Runtime/config-tests/ConfigurationSerializationTests.RestAPI.json

@@ -35,6 +35,7 @@
           "LocationType": "DotVVM.Framework.ResourceManagement.FileResourceLocation, DotVVM.Framework",
           "MimeType": "text/javascript",
           "VerifyResourceIntegrity": true,
+          "FetchPriority": "Auto",
           "RenderPosition": "Anywhere"
         }
       }

src/Tests/Runtime/config-tests/ConfigurationSerializationTests.SerializeDefaultConfig.json

@@ -43,6 +43,7 @@
           "LocationType": "DotVVM.Framework.ResourceManagement.EmbeddedResourceLocation, DotVVM.Framework",
           "MimeType": "text/javascript",
           "VerifyResourceIntegrity": true,
+          "FetchPriority": "Auto",
           "Dependencies": [
             "knockout"
           ],
@@ -58,6 +59,7 @@
           "LocationType": "DotVVM.Framework.ResourceManagement.EmbeddedResourceLocation, DotVVM.Framework",
           "MimeType": "text/javascript",
           "VerifyResourceIntegrity": true,
+          "FetchPriority": "Auto",
           "Dependencies": [
             "knockout"
           ],
@@ -75,6 +77,7 @@
           "LocationType": "DotVVM.Framework.ResourceManagement.EmbeddedResourceLocation, DotVVM.Framework",
           "MimeType": "text/javascript",
           "VerifyResourceIntegrity": true,
+          "FetchPriority": "Auto",
           "Dependencies": [
             "dotvvm"
           ],
@@ -90,6 +93,7 @@
           "LocationType": "DotVVM.Framework.ResourceManagement.EmbeddedResourceLocation, DotVVM.Framework",
           "MimeType": "text/javascript",
           "VerifyResourceIntegrity": true,
+          "FetchPriority": "Auto",
           "RenderPosition": "Anywhere"
         },
         "knockout": {
@@ -102,6 +106,7 @@
           "LocationType": "DotVVM.Framework.ResourceManagement.EmbeddedResourceLocation, DotVVM.Framework",
           "MimeType": "text/javascript",
           "VerifyResourceIntegrity": true,
+          "FetchPriority": "Auto",
           "RenderPosition": "Anywhere"
         }
       },
@@ -115,6 +120,7 @@
           "LocationType": "DotVVM.Framework.ResourceManagement.EmbeddedResourceLocation, DotVVM.Framework",
           "MimeType": "text/css",
           "VerifyResourceIntegrity": true,
+          "FetchPriority": "Auto",
           "RenderPosition": "Head"
         },
         "dotvvm.internal-css": {
@@ -126,6 +132,7 @@
           "LocationType": "DotVVM.Framework.ResourceManagement.EmbeddedResourceLocation, DotVVM.Framework",
           "MimeType": "text/css",
           "VerifyResourceIntegrity": true,
+          "FetchPriority": "Auto",
           "RenderPosition": "Head"
         }
       }

src/Tests/Runtime/config-tests/ConfigurationSerializationTests.SerializeResources.json

@@ -49,6 +49,7 @@
           "MimeType": "text/javascript",
           "VerifyResourceIntegrity": true,
           "IntegrityHash": "hash, maybe",
+          "FetchPriority": "Auto",
           "RenderPosition": "Head"
         },
         "r2": {
@@ -63,6 +64,7 @@
           },
           "MimeType": "text/javascript",
           "VerifyResourceIntegrity": true,
+          "FetchPriority": "Auto",
           "Dependencies": [
             "r1"
           ],
@@ -79,6 +81,7 @@
           "MimeType": "text/css",
           "VerifyResourceIntegrity": true,
           "IntegrityHash": "hash, maybe",
+          "FetchPriority": "Auto",
           "RenderPosition": "Head"
         }
       }

src/Tests/Runtime/testoutputs/ResourceRenderTests.ScriptModule_FetchPriority_High.html

@@ -0,0 +1 @@
+<script src=http://example.com/module.js fetchpriority=low type=module></script>

src/Tests/Runtime/testoutputs/ResourceRenderTests.Script_WithFallback_OnlyPrimaryHasFetchPriority.html

@@ -0,0 +1 @@
+<script src=http://primary.example.com/app.js fetchpriority=high defer></script><script defer src="data:text/javascript;base64,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"></script>

src/Tests/Runtime/testoutputs/ResourceRenderTests.Stylesheet_FetchPriority_High.html

@@ -0,0 +1 @@
+<link href=http://example.com/style.css fetchpriority=high rel=stylesheet type=text/css />

src/Tests/Runtime/testoutputs/ScriptResourceRenderingTests.ScriptModule_FetchPriority_High.html

@@ -0,0 +1 @@
+<script src=http://example.com/module.js fetchpriority=low type=module></script>

src/Tests/Runtime/testoutputs/ScriptResourceRenderingTests.Stylesheet_FetchPriority_High.html

@@ -0,0 +1 @@
+<link href=http://example.com/style.css fetchpriority=high rel=stylesheet type=text/css />