SupplyParameterFromSession support for Blazor

src/Components/Components/src/ISessionValueMapper.cs

@@ -0,0 +1,26 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Components;
+
+/// <summary>
+/// Maps session data values to a model.
+/// </summary>
+public interface ISessionValueMapper
+{
+    /// <summary>
+    /// Returns the session value with the specified name, deserialized to the specified type.
+    /// </summary>
+    object? GetValue(string sessionKey, Type targetType);
+
+    /// <summary>
+    /// Registers a callback to retrieve the current value of a session property.
+    /// The callback will be invoked when the response starts to persist the value.
+    /// </summary>
+    void RegisterValueCallback(string sessionKey, Func<object?> valueGetter);
+
+    /// <summary>
+    /// Unregisters a previously registered callback for the specified session key.
+    /// </summary>
+    void DeleteValueCallback(string sessionKey);
+}

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

@@ -7,3 +7,13 @@ Microsoft.AspNetCore.Components.IComponentPropertyActivator.GetActivator(System.
 *REMOVED*Microsoft.AspNetCore.Components.ResourceAsset.ResourceAsset(string! url, System.Collections.Generic.IReadOnlyList<Microsoft.AspNetCore.Components.ResourceAssetProperty!>? properties) -> void
 *REMOVED*Microsoft.AspNetCore.Components.Routing.Router.PreferExactMatches.get -> bool
 *REMOVED*Microsoft.AspNetCore.Components.Routing.Router.PreferExactMatches.set -> void
+Microsoft.AspNetCore.Components.ISessionValueMapper
+Microsoft.AspNetCore.Components.ISessionValueMapper.DeleteValueCallback(string! sessionKey) -> void
+Microsoft.AspNetCore.Components.ISessionValueMapper.GetValue(string! sessionKey, System.Type! targetType) -> object?
+Microsoft.AspNetCore.Components.ISessionValueMapper.RegisterValueCallback(string! sessionKey, System.Func<object?>! valueGetter) -> void
+Microsoft.AspNetCore.Components.SupplyParameterFromSessionAttribute
+Microsoft.AspNetCore.Components.SupplyParameterFromSessionAttribute.Name.get -> string?
+Microsoft.AspNetCore.Components.SupplyParameterFromSessionAttribute.Name.set -> void
+Microsoft.AspNetCore.Components.SupplyParameterFromSessionAttribute.SupplyParameterFromSessionAttribute() -> void
+Microsoft.AspNetCore.Components.SupplyParameterFromSessionServiceCollectionExtensions
+static Microsoft.AspNetCore.Components.SupplyParameterFromSessionServiceCollectionExtensions.AddSupplyValueFromSessionProvider(this Microsoft.Extensions.DependencyInjection.IServiceCollection! services) -> Microsoft.Extensions.DependencyInjection.IServiceCollection!

src/Components/Components/src/SupplyParameterFromSessionAttribute.cs

@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Components;
+
+/// <summary>
+/// Indicates that the value of the associated property should be supplied from
+/// the session with the specified name.
+/// </summary>
+[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
+public sealed class SupplyParameterFromSessionAttribute : CascadingParameterAttributeBase
+{
+    /// <summary>
+    /// Gets or sets the name of the session key. If not specified, the property name will be used.
+    /// </summary>
+    public string? Name { get; set; }
+
+    /// <inheritdoc />
+    internal override bool SingleDelivery => false;
+}

src/Components/Components/src/SupplyParameterFromSessionServiceCollectionExtensions.cs

@@ -0,0 +1,23 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+namespace Microsoft.AspNetCore.Components;
+
+/// <summary>
+/// Enables component parameters to be supplied from the session with <see cref="SupplyParameterFromSessionAttribute"/>.
+/// </summary>
+public static class SupplyParameterFromSessionServiceCollectionExtensions
+{
+    /// <summary>
+    /// Enables component parameters to be supplied from the session with <see cref="SupplyParameterFromSessionAttribute"/>.
+    /// </summary>
+    /// <param name="services">The <see cref="IServiceCollection"/>.</param>
+    /// <returns>The <see cref="IServiceCollection"/>.</returns>
+    public static IServiceCollection AddSupplyValueFromSessionProvider(this IServiceCollection services)
+    {
+        services.TryAddEnumerable(ServiceDescriptor.Scoped<ICascadingValueSupplier, SupplyParameterFromSessionValueProvider>());
+        return services;
+    }
+}

src/Components/Components/src/SupplyParameterFromSessionValueProvider.cs

@@ -0,0 +1,59 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Diagnostics.CodeAnalysis;
+using Microsoft.AspNetCore.Components.Reflection;
+using Microsoft.AspNetCore.Components.Rendering;
+
+namespace Microsoft.AspNetCore.Components;
+
+internal class SupplyParameterFromSessionValueProvider : ICascadingValueSupplier
+{
+    private readonly ISessionValueMapper _sessionValueMapper;
+
+    public SupplyParameterFromSessionValueProvider(ISessionValueMapper sessionValueMapper)
+    {
+        _sessionValueMapper = sessionValueMapper;
+    }
+
+    public bool IsFixed => false;
+
+    public bool CanSupplyValue(in CascadingParameterInfo parameterInfo)
+        => parameterInfo.Attribute is SupplyParameterFromSessionAttribute;
+
+    public object? GetCurrentValue(object? key, in CascadingParameterInfo parameterInfo)
+    {
+        var attribute = (SupplyParameterFromSessionAttribute)parameterInfo.Attribute;
+        var sessionKey = (attribute.Name ?? parameterInfo.PropertyName) ?? "";
+        return _sessionValueMapper.GetValue(sessionKey, parameterInfo.PropertyType);
+    }
+
+    [UnconditionalSuppressMessage(
+        "Trimming",
+        "IL2075:Target parameter argument does not satisfy 'DynamicallyAccessedMembersAttribute'",
+        Justification = "Component properties are preserved through other means.")]
+    public void Subscribe(ComponentState subscriber, in CascadingParameterInfo parameterInfo)
+    {
+        var attribute = (SupplyParameterFromSessionAttribute)parameterInfo.Attribute;
+        var sessionKey = (attribute.Name ?? parameterInfo.PropertyName) ?? "";
+        var propertyName = parameterInfo.PropertyName;
+        var componentType = subscriber.Component.GetType();
+        var propertyInfo = componentType.GetProperty(propertyName);
+
+        if (propertyInfo is null)
+        {
+            return;
+        }
+
+        var component = subscriber.Component;
+        var getter = new PropertyGetter(componentType, propertyInfo);
+        _sessionValueMapper.RegisterValueCallback(sessionKey, () => getter.GetValue(component));
+    }
+
+    public void Unsubscribe(ComponentState subscriber, in CascadingParameterInfo parameterInfo)
+    {
+        var attribute = (SupplyParameterFromSessionAttribute)parameterInfo.Attribute;
+        var sessionKey = (attribute.Name ?? parameterInfo.PropertyName) ?? "";
+        _sessionValueMapper.DeleteValueCallback(sessionKey);
+    }
+}

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

@@ -69,7 +69,9 @@ public static IRazorComponentsBuilder AddRazorComponents(this IServiceCollection
         services.TryAddScoped<EndpointRoutingStateProvider>();
         services.TryAddScoped<IRoutingStateProvider>(sp => sp.GetRequiredService<EndpointRoutingStateProvider>());
         services.TryAddScoped<AuthenticationStateProvider, ServerAuthenticationStateProvider>();
+        services.TryAddScoped<ISessionValueMapper, SessionValueMapper>();
         services.AddSupplyValueFromQueryProvider();
+        services.AddSupplyValueFromSessionProvider();
         services.AddSupplyValueFromPersistentComponentStateProvider();
         services.TryAddCascadingValue(sp => sp.GetRequiredService<EndpointHtmlRenderer>().HttpContext);
         services.TryAddScoped<WebAssemblySettingsEmitter>();

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

@@ -122,6 +122,11 @@ internal async Task InitializeStandardComponentServicesAsync(
             antiforgery.SetRequestContext(httpContext);
         }
 
+        if (httpContext.RequestServices.GetService<ISessionValueMapper>() is SessionValueMapper sessionValueMapper)
+        {
+            sessionValueMapper.SetRequestContext(httpContext);
+        }
+
         // It's important that this is initialized since a component might try to restore state during prerendering
         // (which will obviously not work, but should not fail)
         var componentApplicationLifetime = httpContext.RequestServices.GetRequiredService<ComponentStatePersistenceManager>();

src/Components/Endpoints/src/Session/SessionValueMapper.cs

@@ -0,0 +1,105 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Text.Json;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http.Features;
+using Microsoft.Extensions.Logging;
+
+namespace Microsoft.AspNetCore.Components.Endpoints;
+
+internal partial class SessionValueMapper : ISessionValueMapper
+{
+    private static readonly JsonSerializerOptions _jsonOptions = new(JsonSerializerDefaults.Web);
+    private HttpContext? _httpContext;
+    private readonly Dictionary<string, Func<object?>> _valueCallbacks = new(StringComparer.OrdinalIgnoreCase);
+    private readonly ILogger<SessionValueMapper> _logger;
+
+    public SessionValueMapper(ILogger<SessionValueMapper> logger)
+    {
+        _logger = logger;
+    }
+
+    internal void SetRequestContext(HttpContext httpContext)
+    {
+        _httpContext = httpContext;
+        _httpContext.Response.OnStarting(PersistAllValues);
+    }
+
+    public object? GetValue(string sessionKey, Type targetType)
+    {
+        var session = _httpContext?.Features.Get<ISessionFeature>()?.Session;
+        if (session is null)
+        {
+            return null;
+        }
+        try
+        {
+            var json = session.GetString(sessionKey.ToLowerInvariant());
+            if (string.IsNullOrEmpty(json))
+            {
+                return null;
+            }
+            return JsonSerializer.Deserialize(json, targetType, _jsonOptions);
+        }
+        catch (JsonException ex)
+        {
+            Log.SessionDeserializeFail(_logger, ex);
+            return null;
+        }
+    }
+
+    public void RegisterValueCallback(string sessionKey, Func<object?> valueGetter)
+    {
+        if (!_valueCallbacks.TryAdd(sessionKey, valueGetter))
+        {
+            throw new InvalidOperationException($"A callback is already registered for the session key '{sessionKey}'. Multiple components cannot use the same session key.");
+        }
+    }
+
+    public void DeleteValueCallback(string sessionKey)
+    {
+        _valueCallbacks.Remove(sessionKey);
+    }
+
+    private Task PersistAllValues()
+    {
+        var session = _httpContext?.Features.Get<ISessionFeature>()?.Session;
+        if (session is null)
+        {
+            return Task.CompletedTask;
+        }
+
+        foreach (var (key, valueGetter) in _valueCallbacks)
+        {
+            object? value = null;
+            try
+            {
+                value = valueGetter();
+            }
+            catch (Exception ex)
+            {
+                Log.SessionPersistFail(_logger, ex);
+            }
+            if (value is not null)
+            {
+                var json = JsonSerializer.Serialize(value, value.GetType(), _jsonOptions);
+                session.SetString(key.ToLowerInvariant(), json);
+            }
+            else
+            {
+                session.Remove(key.ToLowerInvariant());
+            }
+        }
+        return Task.CompletedTask;
+    }
+
+    private static partial class Log
+    {
+        [LoggerMessage(1, LogLevel.Warning, "Persisting of the element failed.", EventName = "SessionPersistFail")]
+        public static partial void SessionPersistFail(ILogger logger, Exception exception);
+
+        [LoggerMessage(2, LogLevel.Warning, "Deserialization of the element from Session failed.", EventName = "SessionDeserializeFail")]
+        public static partial void SessionDeserializeFail(ILogger logger, JsonException exception);
+    }
+}