VCST-5468: Resolve IMediator from request scope in GraphQL builders and add IRequestScopedCache

src/VirtoCommerce.Xapi.Core/BaseQueries/CommandBuilder.cs

@@ -17,8 +17,14 @@ public abstract class CommandBuilder<TCommand, TResult, TCommandGraphType, TResu
 {
     private const string _argumentName = "command";
 
+    protected CommandBuilder(IAuthorizationService authorizationService)
+        : base(authorizationService)
+    {
+    }
+
+    [Obsolete("Use the constructor without IMediator. The mediator is resolved from context.RequestServices per request.", DiagnosticId = "VC0015", UrlFormat = "https://docs.virtocommerce.org/products/products-virto3-versions")]
     protected CommandBuilder(IMediator mediator, IAuthorizationService authorizationService)
-        : base(mediator, authorizationService)
+        : this(authorizationService)
     {
     }
 
@@ -47,8 +53,14 @@ public abstract class CommandBuilder<TCommand, TResult, TResultGraphType>
     where TCommand : IRequest<TResult>
     where TResultGraphType : IGraphType
 {
+    protected CommandBuilder(IAuthorizationService authorizationService)
+        : base(authorizationService)
+    {
+    }
+
+    [Obsolete("Use the constructor without IMediator. The mediator is resolved from context.RequestServices per request.", DiagnosticId = "VC0015", UrlFormat = "https://docs.virtocommerce.org/products/products-virto3-versions")]
     protected CommandBuilder(IMediator mediator, IAuthorizationService authorizationService)
-        : base(mediator, authorizationService)
+        : this(authorizationService)
     {
     }
 
@@ -60,7 +72,7 @@ public override void Build(ISchema schema)
     protected override IEnumerable<QueryArgument> GetArguments()
     {
         // no arguments needed for this type of command builder
-        return Array.Empty<QueryArgument>();
+        return [];
     }
 
     protected override TCommand GetRequest(IResolveFieldContext<object> context)

src/VirtoCommerce.Xapi.Core/BaseQueries/QueryBuilder.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using GraphQL;
 using GraphQL.Types;
@@ -13,8 +14,14 @@ public abstract class QueryBuilder<TQuery, TResult, TResultGraphType>
     where TQuery : IQuery<TResult>, IExtendableQuery, IHasArguments
     where TResultGraphType : IGraphType
 {
+    protected QueryBuilder(IAuthorizationService authorizationService)
+        : base(authorizationService)
+    {
+    }
+
+    [Obsolete("Use the constructor without IMediator. The mediator is resolved from context.RequestServices per request.", DiagnosticId = "VC0015", UrlFormat = "https://docs.virtocommerce.org/products/products-virto3-versions")]
     protected QueryBuilder(IMediator mediator, IAuthorizationService authorizationService)
-        : base(mediator, authorizationService)
+        : this(authorizationService)
     {
     }
 

src/VirtoCommerce.Xapi.Core/BaseQueries/RequestBuilder.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
 using GraphQL;
@@ -16,17 +17,19 @@ public abstract class RequestBuilder<TRequest, TResponse, TResponseGraphType> :
     where TRequest : IRequest<TResponse>
     where TResponseGraphType : IGraphType
 {
-    private readonly IMediator _mediator;
     private readonly IAuthorizationService _authorizationService;
 
     protected abstract string Name { get; }
 
-    protected RequestBuilder(
-        IMediator mediator,
-        IAuthorizationService authorizationService)
+    protected RequestBuilder(IAuthorizationService authorizationService)
     {
         _authorizationService = authorizationService;
-        _mediator = mediator;
+    }
+
+    [Obsolete("Use the constructor without IMediator. The mediator is resolved from context.RequestServices per request.", DiagnosticId = "VC0015", UrlFormat = "https://docs.virtocommerce.org/products/products-virto3-versions")]
+    protected RequestBuilder(IMediator mediator, IAuthorizationService authorizationService)
+        : this(authorizationService)
+    {
     }
 
     public abstract void Build(ISchema schema);
@@ -38,6 +41,7 @@ protected virtual FieldType GetFieldType()
             .ResolveAsync(async context =>
             {
                 var (_, response) = await Resolve(context);
+
                 return response;
             });
 
@@ -83,7 +87,8 @@ protected virtual Task AfterMediatorSend(IResolveFieldContext<object> context, T
 
     protected virtual async Task<TResponse> GetResponseAsync(IResolveFieldContext<object> context, TRequest request)
     {
-        return await _mediator.Send(request);
+        // Not ctor-injected: builders are singletons, a ctor-captured mediator would be root-bound (see GetMediator docs).
+        return await context.GetMediator().Send(request);
     }
 
     protected virtual async Task Authorize(IResolveFieldContext context, object resource, IAuthorizationRequirement requirement)

src/VirtoCommerce.Xapi.Core/BaseQueries/SearchQueryBuilder.cs

@@ -1,3 +1,4 @@
+using System;
 using GraphQL.Types;
 using MediatR;
 using Microsoft.AspNetCore.Authorization;
@@ -16,8 +17,14 @@ public abstract class SearchQueryBuilder<TQuery, TResult, TItem, TItemGraphType>
 {
     protected virtual int DefaultPageSize => Connections.DefaultPageSize;
 
+    protected SearchQueryBuilder(IAuthorizationService authorizationService)
+        : base(authorizationService)
+    {
+    }
+
+    [Obsolete("Use the constructor without IMediator. The mediator is resolved from context.RequestServices per request.", DiagnosticId = "VC0015", UrlFormat = "https://docs.virtocommerce.org/products/products-virto3-versions")]
     protected SearchQueryBuilder(IMediator mediator, IAuthorizationService authorizationService)
-        : base(mediator, authorizationService)
+        : this(authorizationService)
     {
     }
 
@@ -31,6 +38,7 @@ protected override FieldType GetFieldType()
         builder.ResolveAsync(async context =>
         {
             var (query, response) = await Resolve(context);
+
             return new PagedConnection<TItem>(response.Results, query.Skip, query.Take, response.TotalCount);
         });
 

src/VirtoCommerce.Xapi.Core/Extensions/RequestScopedCacheExtensions.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using VirtoCommerce.Platform.Core.Common;
+using VirtoCommerce.Xapi.Core.Services;
+
+namespace VirtoCommerce.Xapi.Core.Extensions;
+
+public static class RequestScopedCacheExtensions
+{
+    /// <summary>
+    /// By-id form for items keyed by <see cref="IEntity.Id"/>: delegates to
+    /// <see cref="IRequestScopedCache.GetOrLoadByIdsAsync{T}(string, ICollection{string}, Func{T, string}, Func{ICollection{string}, Task{IList{T}}})"/>.
+    /// </summary>
+    public static Task<IDictionary<string, T>> GetOrLoadByIdsAsync<T>(
+        this IRequestScopedCache cache,
+        string keyPrefix,
+        ICollection<string> ids,
+        Func<ICollection<string>, Task<IList<T>>> loadMissing)
+        where T : class, IEntity
+    {
+        return cache.GetOrLoadByIdsAsync(keyPrefix, ids, static x => x.Id, loadMissing);
+    }
+}