In SSR, supply HttpContext as cascading value

src/Components/Components/src/CascadingParameterAttribute.cs

@@ -20,5 +20,5 @@ public sealed class CascadingParameterAttribute : CascadingParameterAttributeBas
     /// <see cref="CascadingValue{T}"/>  that supplies a value with a compatible
     /// type.
     /// </summary>
-    public override string? Name { get; set; }
+    public string? Name { get; set; }
 }

src/Components/Components/src/CascadingParameterAttributeBase.cs

@@ -8,12 +8,6 @@ namespace Microsoft.AspNetCore.Components;
 /// </summary>
 public abstract class CascadingParameterAttributeBase : Attribute
 {
-    /// <summary>
-    /// Gets or sets the name for the parameter, which correlates to the name
-    /// of a cascading value.
-    /// </summary>
-    public abstract string? Name { get; set; }
-
     /// <summary>
     /// Gets a flag indicating whether the cascading parameter should
     /// be supplied only once per component.

src/Components/Components/src/CascadingValueServiceCollectionExtensions.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using Microsoft.AspNetCore.Components;
+using Microsoft.Extensions.DependencyInjection.Extensions;
 
 namespace Microsoft.Extensions.DependencyInjection;
 
@@ -50,4 +51,59 @@ public static IServiceCollection AddCascadingValue<TValue>(
     public static IServiceCollection AddCascadingValue<TValue>(
         this IServiceCollection serviceCollection, Func<IServiceProvider, CascadingValueSource<TValue>> sourceFactory)
         => serviceCollection.AddScoped<ICascadingValueSupplier>(sourceFactory);
+
+    /// <summary>
+    /// Adds a cascading value to the <paramref name="serviceCollection"/>, if none is already registered
+    /// with the value type. This is equivalent to having a fixed <see cref="CascadingValue{TValue}"/> at
+    /// the root of the component hierarchy.
+    /// </summary>
+    /// <typeparam name="TValue">The value type.</typeparam>
+    /// <param name="serviceCollection">The <see cref="IServiceCollection"/>.</param>
+    /// <param name="valueFactory">A callback that supplies a fixed value within each service provider scope.</param>
+    /// <returns>The <see cref="IServiceCollection"/>.</returns>
+    public static void TryAddCascadingValue<TValue>(
+        this IServiceCollection serviceCollection, Func<IServiceProvider, TValue> valueFactory)
+    {
+        serviceCollection.TryAddEnumerable(
+            ServiceDescriptor.Scoped<ICascadingValueSupplier, CascadingValueSource<TValue>>(
+                sp => new CascadingValueSource<TValue>(() => valueFactory(sp), isFixed: true)));
+    }
+
+    /// <summary>
+    /// Adds a cascading value to the <paramref name="serviceCollection"/>, if none is already registered
+    /// with the value type, regardless of the <paramref name="name"/>. This is equivalent to having a fixed
+    /// <see cref="CascadingValue{TValue}"/> at the root of the component hierarchy.
+    /// </summary>
+    /// <typeparam name="TValue">The value type.</typeparam>
+    /// <param name="serviceCollection">The <see cref="IServiceCollection"/>.</param>
+    /// <param name="name">A name for the cascading value. If set, <see cref="CascadingParameterAttribute"/> can be configured to match based on this name.</param>
+    /// <param name="valueFactory">A callback that supplies a fixed value within each service provider scope.</param>
+    /// <returns>The <see cref="IServiceCollection"/>.</returns>
+    public static void TryAddCascadingValue<TValue>(
+        this IServiceCollection serviceCollection, string name, Func<IServiceProvider, TValue> valueFactory)
+    {
+        serviceCollection.TryAddEnumerable(
+            ServiceDescriptor.Scoped<ICascadingValueSupplier, CascadingValueSource<TValue>>(
+                sp => new CascadingValueSource<TValue>(name, () => valueFactory(sp), isFixed: true)));
+    }
+
+    /// <summary>
+    /// Adds a cascading value to the <paramref name="serviceCollection"/>, if none is already registered
+    /// with the value type. This is equivalent to having a fixed <see cref="CascadingValue{TValue}"/> at
+    /// the root of the component hierarchy.
+    /// 
+    /// With this overload, you can supply a <see cref="CascadingValueSource{TValue}"/> which allows you
+    /// to notify about updates to the value later, causing recipients to re-render. This overload should
+    /// only be used if you plan to update the value dynamically.
+    /// </summary>
+    /// <typeparam name="TValue">The value type.</typeparam>
+    /// <param name="serviceCollection">The <see cref="IServiceCollection"/>.</param>
+    /// <param name="sourceFactory">A callback that supplies a <see cref="CascadingValueSource{TValue}"/> within each service provider scope.</param>
+    /// <returns>The <see cref="IServiceCollection"/>.</returns>
+    public static void TryAddCascadingValue<TValue>(
+        this IServiceCollection serviceCollection, Func<IServiceProvider, CascadingValueSource<TValue>> sourceFactory)
+    {
+        serviceCollection.TryAddEnumerable(
+            ServiceDescriptor.Scoped<ICascadingValueSupplier, CascadingValueSource<TValue>>(sourceFactory));
+    }
 }

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

@@ -1,6 +1,4 @@
 #nullable enable
-abstract Microsoft.AspNetCore.Components.CascadingParameterAttributeBase.Name.get -> string?
-abstract Microsoft.AspNetCore.Components.CascadingParameterAttributeBase.Name.set -> void
 abstract Microsoft.AspNetCore.Components.RenderModeAttribute.Mode.get -> Microsoft.AspNetCore.Components.IComponentRenderMode!
 Microsoft.AspNetCore.Components.CascadingParameterAttributeBase
 Microsoft.AspNetCore.Components.CascadingParameterAttributeBase.CascadingParameterAttributeBase() -> void
@@ -83,24 +81,19 @@ Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder.AddComponentParamete
 Microsoft.AspNetCore.Components.StreamRenderingAttribute
 Microsoft.AspNetCore.Components.StreamRenderingAttribute.Enabled.get -> bool
 Microsoft.AspNetCore.Components.StreamRenderingAttribute.StreamRenderingAttribute(bool enabled) -> void
-*REMOVED*Microsoft.AspNetCore.Components.CascadingParameterAttribute.Name.get -> string?
-*REMOVED*Microsoft.AspNetCore.Components.CascadingParameterAttribute.Name.set -> void
 Microsoft.AspNetCore.Components.SupplyParameterFromQueryProviderServiceCollectionExtensions
 Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions
-override Microsoft.AspNetCore.Components.CascadingParameterAttribute.Name.get -> string?
-override Microsoft.AspNetCore.Components.CascadingParameterAttribute.Name.set -> void
 override Microsoft.AspNetCore.Components.EventCallback.GetHashCode() -> int
 override Microsoft.AspNetCore.Components.EventCallback.Equals(object? obj) -> bool
 override Microsoft.AspNetCore.Components.EventCallback<TValue>.GetHashCode() -> int
 override Microsoft.AspNetCore.Components.EventCallback<TValue>.Equals(object? obj) -> bool
-*REMOVED*Microsoft.AspNetCore.Components.SupplyParameterFromQueryAttribute.Name.get -> string?
-*REMOVED*Microsoft.AspNetCore.Components.SupplyParameterFromQueryAttribute.Name.set -> void
-override Microsoft.AspNetCore.Components.SupplyParameterFromQueryAttribute.Name.get -> string?
-override Microsoft.AspNetCore.Components.SupplyParameterFromQueryAttribute.Name.set -> void
 static Microsoft.AspNetCore.Components.SupplyParameterFromQueryProviderServiceCollectionExtensions.AddSupplyValueFromQueryProvider(this Microsoft.Extensions.DependencyInjection.IServiceCollection! services) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
 static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.AddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, string! name, System.Func<System.IServiceProvider!, TValue>! valueFactory) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
 static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.AddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, System.Func<System.IServiceProvider!, Microsoft.AspNetCore.Components.CascadingValueSource<TValue>!>! sourceFactory) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
 static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.AddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, System.Func<System.IServiceProvider!, TValue>! valueFactory) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!
+static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.TryAddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, string! name, System.Func<System.IServiceProvider!, TValue>! valueFactory) -> void
+static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.TryAddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, System.Func<System.IServiceProvider!, Microsoft.AspNetCore.Components.CascadingValueSource<TValue>!>! sourceFactory) -> void
+static Microsoft.Extensions.DependencyInjection.CascadingValueServiceCollectionExtensions.TryAddCascadingValue<TValue>(this Microsoft.Extensions.DependencyInjection.IServiceCollection! serviceCollection, System.Func<System.IServiceProvider!, TValue>! valueFactory) -> void
 virtual Microsoft.AspNetCore.Components.NavigationManager.Refresh(bool forceReload = false) -> void
 virtual Microsoft.AspNetCore.Components.Rendering.ComponentState.DisposeAsync() -> System.Threading.Tasks.ValueTask
 virtual Microsoft.AspNetCore.Components.RenderTree.Renderer.AddPendingTask(Microsoft.AspNetCore.Components.Rendering.ComponentState? componentState, System.Threading.Tasks.Task! task) -> void

src/Components/Components/src/Reflection/ComponentProperties.cs

@@ -184,8 +184,7 @@ private static void ThrowForUnknownIncomingParameterName([DynamicallyAccessedMem
             {
                 throw new InvalidOperationException(
                     $"Object of type '{targetType.FullName}' has a property matching the name '{parameterName}', " +
-                    $"but it does not have [{nameof(ParameterAttribute)}], [{nameof(CascadingParameterAttribute)}] or " +
-                    $"[SupplyParameterFromFormAttribute] applied.");
+                    $"but it does not have [Parameter], [CascadingParameter], or any other parameter-supplying attribute.");
             }
             else
             {

src/Components/Components/src/SupplyParameterFromQueryAttribute.cs

@@ -14,5 +14,5 @@ public sealed class SupplyParameterFromQueryAttribute : CascadingParameterAttrib
     /// Gets or sets the name of the querystring parameter. If null, the querystring
     /// parameter is assumed to have the same name as the associated property.
     /// </summary>
-    public override string? Name { get; set; }
+    public string? Name { get; set; }
 }

src/Components/Components/src/SupplyParameterFromQueryProviderServiceCollectionExtensions.cs

@@ -50,7 +50,8 @@ public bool CanSupplyValue(in CascadingParameterInfo parameterInfo)
                 UpdateQueryParameters();
             }
 
-            var queryParameterName = parameterInfo.Attribute.Name ?? parameterInfo.PropertyName;
+            var attribute = (SupplyParameterFromQueryAttribute)parameterInfo.Attribute; // Must be a valid cast because we check in CanSupplyValue
+            var queryParameterName = attribute.Name ?? parameterInfo.PropertyName;
             return _queryParameterValueSupplier.GetQueryParameterValue(parameterInfo.PropertyType, queryParameterName);
         }
 

src/Components/Components/test/CascadingParameterStateTest.cs

@@ -476,8 +476,6 @@ class ComponentWithNamedCascadingParam : TestComponentBase
 
     class SupplyParameterWithSingleDeliveryAttribute : CascadingParameterAttributeBase
     {
-        public override string Name { get; set; }
-
         internal override bool SingleDelivery => true;
     }
 
@@ -523,19 +521,3 @@ public TestNavigationManager()
         }
     }
 }
-
-[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
-public sealed class SupplyParameterFromFormAttribute : CascadingParameterAttributeBase
-{
-    /// <summary>
-    /// Gets or sets the name for the parameter. The name is used to match
-    /// the form data and decide whether or not the value needs to be bound.
-    /// </summary>
-    public override string Name { get; set; }
-
-    /// <summary>
-    /// Gets or sets the name for the handler. The name is used to match
-    /// the form data and decide whether or not the value needs to be bound.
-    /// </summary>
-    public string Handler { get; set; }
-}

src/Components/Components/test/CascadingParameterTest.cs

@@ -727,15 +727,58 @@ public void OmitsSingleDeliveryCascadingParametersWhenUpdatingDirectParameters()
             });
     }
 
+    [Fact]
+    public void CanUseTryAddPatternForCascadingValuesInServiceCollection_ValueFactory()
+    {
+        // Arrange
+        var services = new ServiceCollection();
+
+        // Act
+        services.TryAddCascadingValue(_ => new Type1());
+        services.TryAddCascadingValue(_ => new Type1());
+        services.TryAddCascadingValue(_ => new Type2());
+
+        // Assert
+        Assert.Equal(2, services.Count());
+    }
+
+    [Fact]
+    public void CanUseTryAddPatternForCascadingValuesInServiceCollection_NamedValueFactory()
+    {
+        // Arrange
+        var services = new ServiceCollection();
+
+        // Act
+        services.TryAddCascadingValue("Name1", _ => new Type1());
+        services.TryAddCascadingValue("Name2", _ => new Type1());
+        services.TryAddCascadingValue("Name3", _ => new Type2());
+
+        // Assert
+        Assert.Equal(2, services.Count());
+    }
+
+    [Fact]
+    public void CanUseTryAddPatternForCascadingValuesInServiceCollection_CascadingValueSource()
+    {
+        // Arrange
+        var services = new ServiceCollection();
+
+        // Act
+        services.TryAddCascadingValue(_ => new CascadingValueSource<Type1>("Name1", new Type1(), false));
+        services.TryAddCascadingValue(_ => new CascadingValueSource<Type1>("Name2", new Type1(), false));
+        services.TryAddCascadingValue(_ => new CascadingValueSource<Type2>("Name3", new Type2(), false));
+
+        // Assert
+        Assert.Equal(2, services.Count());
+    }
+
     private class SingleDeliveryValue(string text)
     {
         public string Text => text;
     }
 
     private class SingleDeliveryCascadingParameterAttribute : CascadingParameterAttributeBase
     {
-        public override string Name { get; set; }
-
         internal override bool SingleDelivery => true;
     }
 
@@ -852,13 +895,11 @@ class SecondCascadingParameterConsumerComponent<T1, T2> : CascadingParameterCons
     [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
     class CustomCascadingParameter1Attribute : CascadingParameterAttributeBase
     {
-        public override string Name { get; set; }
     }
 
     [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
     class CustomCascadingParameter2Attribute : CascadingParameterAttributeBase
     {
-        public override string Name { get; set; }
     }
 
     class CustomCascadingValueProducer<TAttribute> : AutoRenderComponent, ICascadingValueSupplier
@@ -904,7 +945,7 @@ void ICascadingValueSupplier.Unsubscribe(ComponentState subscriber, in Cascading
 
     class CustomCascadingValueConsumer1 : AutoRenderComponent
     {
-        [CustomCascadingParameter1(Name = nameof(Value))]
+        [CustomCascadingParameter1]
         public object Value { get; set; }
 
         protected override void BuildRenderTree(RenderTreeBuilder builder)
@@ -915,7 +956,7 @@ protected override void BuildRenderTree(RenderTreeBuilder builder)
 
     class CustomCascadingValueConsumer2 : AutoRenderComponent
     {
-        [CustomCascadingParameter2(Name = nameof(Value))]
+        [CustomCascadingParameter2]
         public object Value { get; set; }
 
         protected override void BuildRenderTree(RenderTreeBuilder builder)
@@ -944,4 +985,7 @@ public void ChangeValue(string newValue)
             StringValue = newValue;
         }
     }
+
+    class Type1 { }
+    class Type2 { }
 }

src/Components/Components/test/ParameterViewTest.Assignment.cs

@@ -183,7 +183,7 @@ public void IncomingParameterMatchesPropertyNotDeclaredAsParameter_Throws()
         Assert.Equal(default, target.IntProp);
         Assert.Equal(
             $"Object of type '{typeof(HasPropertyWithoutParameterAttribute).FullName}' has a property matching the name '{nameof(HasPropertyWithoutParameterAttribute.IntProp)}', " +
-            $"but it does not have [{nameof(ParameterAttribute)}], [{nameof(CascadingParameterAttribute)}] or [{nameof(SupplyParameterFromFormAttribute)}] applied.",
+            "but it does not have [Parameter], [CascadingParameter], or any other parameter-supplying attribute.",
             ex.Message);
     }
 

src/Components/Endpoints/src/DependencyInjection/RazorComponentsServiceCollectionExtensions.cs

@@ -63,6 +63,7 @@ public static IRazorComponentsBuilder AddRazorComponents(this IServiceCollection
         services.TryAddScoped<EndpointRoutingStateProvider>();
         services.TryAddScoped<IRoutingStateProvider>(sp => sp.GetRequiredService<EndpointRoutingStateProvider>());
         services.AddSupplyValueFromQueryProvider();
+        services.TryAddCascadingValue(sp => sp.GetRequiredService<EndpointHtmlRenderer>().HttpContext);
 
         // Form handling
         services.AddSupplyValueFromFormProvider();

src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.cs

@@ -52,6 +52,8 @@ public EndpointHtmlRenderer(IServiceProvider serviceProvider, ILoggerFactory log
         _services = serviceProvider;
     }
 
+    internal HttpContext? HttpContext => _httpContext;
+
     private void SetHttpContext(HttpContext httpContext)
     {
         if (_httpContext is null)