Tryout: tracking versions in atomic:operations

src/JsonApiDotNetCore/AtomicOperations/IVersionTracker.cs

@@ -0,0 +1,13 @@
+using JsonApiDotNetCore.Configuration;
+using JsonApiDotNetCore.Resources;
+
+namespace JsonApiDotNetCore.AtomicOperations;
+
+public interface IVersionTracker
+{
+    bool RequiresVersionTracking();
+
+    void CaptureVersions(ResourceType resourceType, IIdentifiable resource);
+
+    string? GetVersion(ResourceType resourceType, string stringId);
+}

src/JsonApiDotNetCore/AtomicOperations/OperationsProcessor.cs

@@ -15,19 +15,21 @@ public class OperationsProcessor : IOperationsProcessor
     private readonly IOperationProcessorAccessor _operationProcessorAccessor;
     private readonly IOperationsTransactionFactory _operationsTransactionFactory;
     private readonly ILocalIdTracker _localIdTracker;
+    private readonly IVersionTracker _versionTracker;
     private readonly IResourceGraph _resourceGraph;
     private readonly IJsonApiRequest _request;
     private readonly ITargetedFields _targetedFields;
     private readonly ISparseFieldSetCache _sparseFieldSetCache;
     private readonly LocalIdValidator _localIdValidator;
 
     public OperationsProcessor(IOperationProcessorAccessor operationProcessorAccessor, IOperationsTransactionFactory operationsTransactionFactory,
-        ILocalIdTracker localIdTracker, IResourceGraph resourceGraph, IJsonApiRequest request, ITargetedFields targetedFields,
+        ILocalIdTracker localIdTracker, IVersionTracker versionTracker, IResourceGraph resourceGraph, IJsonApiRequest request, ITargetedFields targetedFields,
         ISparseFieldSetCache sparseFieldSetCache)
     {
         ArgumentGuard.NotNull(operationProcessorAccessor);
         ArgumentGuard.NotNull(operationsTransactionFactory);
         ArgumentGuard.NotNull(localIdTracker);
+        ArgumentGuard.NotNull(versionTracker);
         ArgumentGuard.NotNull(resourceGraph);
         ArgumentGuard.NotNull(request);
         ArgumentGuard.NotNull(targetedFields);
@@ -36,6 +38,7 @@ public OperationsProcessor(IOperationProcessorAccessor operationProcessorAccesso
         _operationProcessorAccessor = operationProcessorAccessor;
         _operationsTransactionFactory = operationsTransactionFactory;
         _localIdTracker = localIdTracker;
+        _versionTracker = versionTracker;
         _resourceGraph = resourceGraph;
         _request = request;
         _targetedFields = targetedFields;
@@ -104,11 +107,15 @@ public OperationsProcessor(IOperationProcessorAccessor operationProcessorAccesso
         cancellationToken.ThrowIfCancellationRequested();
 
         TrackLocalIdsForOperation(operation);
+        RefreshVersionsForOperation(operation);
 
         _targetedFields.CopyFrom(operation.TargetedFields);
         _request.CopyFrom(operation.Request);
 
         return await _operationProcessorAccessor.ProcessAsync(operation, cancellationToken);
+
+        // Ideally we'd take the versions from response here and update the version cache, but currently
+        // not all resource service methods return data. Therefore this is handled elsewhere.
     }
 
     protected void TrackLocalIdsForOperation(OperationContainer operation)
@@ -144,4 +151,36 @@ private void AssignStringId(IIdentifiable resource)
             resource.StringId = _localIdTracker.GetValue(resource.LocalId, resourceType);
         }
     }
+
+    private void RefreshVersionsForOperation(OperationContainer operation)
+    {
+        if (operation.Request.PrimaryResourceType!.IsVersioned)
+        {
+            string? requestVersion = operation.Resource.GetVersion();
+
+            if (requestVersion == null)
+            {
+                string? trackedVersion = _versionTracker.GetVersion(operation.Request.PrimaryResourceType, operation.Resource.StringId!);
+                operation.Resource.SetVersion(trackedVersion);
+
+                ((JsonApiRequest)operation.Request).PrimaryVersion = trackedVersion;
+            }
+        }
+
+        foreach (IIdentifiable rightResource in operation.GetSecondaryResources())
+        {
+            ResourceType rightResourceType = _resourceGraph.GetResourceType(rightResource.GetClrType());
+
+            if (rightResourceType.IsVersioned)
+            {
+                string? requestVersion = rightResource.GetVersion();
+
+                if (requestVersion == null)
+                {
+                    string? trackedVersion = _versionTracker.GetVersion(rightResourceType, rightResource.StringId!);
+                    rightResource.SetVersion(trackedVersion);
+                }
+            }
+        }
+    }
 }

src/JsonApiDotNetCore/AtomicOperations/VersionTracker.cs

@@ -0,0 +1,91 @@
+using JsonApiDotNetCore.Configuration;
+using JsonApiDotNetCore.Middleware;
+using JsonApiDotNetCore.Resources;
+using JsonApiDotNetCore.Resources.Annotations;
+
+namespace JsonApiDotNetCore.AtomicOperations;
+
+public sealed class VersionTracker : IVersionTracker
+{
+    private static readonly CollectionConverter CollectionConverter = new();
+
+    private readonly ITargetedFields _targetedFields;
+    private readonly IJsonApiRequest _request;
+    private readonly Dictionary<string, string> _versionPerResource = new();
+
+    public VersionTracker(ITargetedFields targetedFields, IJsonApiRequest request)
+    {
+        ArgumentGuard.NotNull(targetedFields, nameof(targetedFields));
+        ArgumentGuard.NotNull(request, nameof(request));
+
+        _targetedFields = targetedFields;
+        _request = request;
+    }
+
+    public bool RequiresVersionTracking()
+    {
+        if (_request.Kind != EndpointKind.AtomicOperations)
+        {
+            return false;
+        }
+
+        return _request.PrimaryResourceType!.IsVersioned || _targetedFields.Relationships.Any(relationship => relationship.RightType.IsVersioned);
+    }
+
+    public void CaptureVersions(ResourceType resourceType, IIdentifiable resource)
+    {
+        if (_request.Kind == EndpointKind.AtomicOperations)
+        {
+            if (resourceType.IsVersioned)
+            {
+                string? leftVersion = resource.GetVersion();
+                SetVersion(resourceType, resource.StringId!, leftVersion);
+            }
+
+            foreach (RelationshipAttribute relationship in _targetedFields.Relationships)
+            {
+                if (relationship.RightType.IsVersioned)
+                {
+                    CaptureVersionsInRelationship(resource, relationship);
+                }
+            }
+        }
+    }
+
+    private void CaptureVersionsInRelationship(IIdentifiable resource, RelationshipAttribute relationship)
+    {
+        object? afterRightValue = relationship.GetValue(resource);
+        IReadOnlyCollection<IIdentifiable> afterRightResources = CollectionConverter.ExtractResources(afterRightValue);
+
+        foreach (IIdentifiable rightResource in afterRightResources)
+        {
+            string? rightVersion = rightResource.GetVersion();
+            SetVersion(relationship.RightType, rightResource.StringId!, rightVersion);
+        }
+    }
+
+    private void SetVersion(ResourceType resourceType, string stringId, string? version)
+    {
+        string key = GetKey(resourceType, stringId);
+
+        if (version == null)
+        {
+            _versionPerResource.Remove(key);
+        }
+        else
+        {
+            _versionPerResource[key] = version;
+        }
+    }
+
+    public string? GetVersion(ResourceType resourceType, string stringId)
+    {
+        string key = GetKey(resourceType, stringId);
+        return _versionPerResource.TryGetValue(key, out string? version) ? version : null;
+    }
+
+    private string GetKey(ResourceType resourceType, string stringId)
+    {
+        return $"{resourceType.PublicName}::{stringId}";
+    }
+}

src/JsonApiDotNetCore/Configuration/JsonApiApplicationBuilder.cs

@@ -275,6 +275,7 @@ private void AddOperationsLayer()
         _services.AddScoped<IOperationsProcessor, OperationsProcessor>();
         _services.AddScoped<IOperationProcessorAccessor, OperationProcessorAccessor>();
         _services.AddScoped<ILocalIdTracker, LocalIdTracker>();
+        _services.AddScoped<IVersionTracker, VersionTracker>();
     }
 
     public void Dispose()

src/JsonApiDotNetCore/Queries/IQueryLayerComposer.cs

@@ -47,6 +47,11 @@ QueryLayer WrapLayerForSecondaryEndpoint<TId>(QueryLayer secondaryLayer, Resourc
     /// </summary>
     QueryLayer ComposeForUpdate<TId>(TId id, ResourceType primaryResourceType);
 
+    /// <summary>
+    /// Builds a query that retrieves the primary resource, along with the subset of versioned targeted relationships, after a create/update/delete request.
+    /// </summary>
+    QueryLayer ComposeForGetVersionsAfterWrite<TId>(TId id, ResourceType primaryResourceType, TopFieldSelection fieldSelection);
+
     /// <summary>
     /// Builds a query for each targeted relationship with a filter to match on its right resource IDs.
     /// </summary>

src/JsonApiDotNetCore/Queries/Internal/QueryLayerComposer.cs

@@ -394,6 +394,46 @@ public QueryLayer ComposeForUpdate<TId>(TId id, ResourceType primaryResourceType
         return primaryLayer;
     }
 
+    public QueryLayer ComposeForGetVersionsAfterWrite<TId>(TId id, ResourceType primaryResourceType, TopFieldSelection fieldSelection)
+    {
+        ArgumentGuard.NotNull(primaryResourceType, nameof(primaryResourceType));
+
+        // @formatter:wrap_chained_method_calls chop_always
+        // @formatter:keep_existing_linebreaks true
+
+        IImmutableSet<IncludeElementExpression> includeElements = _targetedFields.Relationships
+            .Where(relationship => relationship.RightType.IsVersioned)
+            .Select(relationship => new IncludeElementExpression(relationship))
+            .ToImmutableHashSet();
+
+        // @formatter:keep_existing_linebreaks restore
+        // @formatter:wrap_chained_method_calls restore
+
+        AttrAttribute primaryIdAttribute = GetIdAttribute(primaryResourceType);
+
+        QueryLayer primaryLayer = new(primaryResourceType)
+        {
+            Include = includeElements.Any() ? new IncludeExpression(includeElements) : IncludeExpression.Empty,
+            Filter = CreateFilterByIds(id.AsArray(), primaryIdAttribute, null)
+        };
+
+        if (fieldSelection == TopFieldSelection.OnlyIdAttribute)
+        {
+            var primarySelection = new FieldSelection();
+            FieldSelectors primarySelectors = primarySelection.GetOrCreateSelectors(primaryLayer.ResourceType);
+            primarySelectors.IncludeAttribute(primaryIdAttribute);
+
+            foreach (IncludeElementExpression include in includeElements)
+            {
+                primarySelectors.IncludeRelationship(include.Relationship, null);
+            }
+
+            primaryLayer.Selection = primarySelection;
+        }
+
+        return primaryLayer;
+    }
+
     /// <inheritdoc />
     public IEnumerable<(QueryLayer, RelationshipAttribute)> ComposeForGetTargetedSecondaryResourceIds(IIdentifiable primaryResource)
     {

src/JsonApiDotNetCore/Services/JsonApiResourceService.cs

@@ -2,6 +2,7 @@
 using System.Net;
 using System.Runtime.CompilerServices;
 using JetBrains.Annotations;
+using JsonApiDotNetCore.AtomicOperations;
 using JsonApiDotNetCore.Configuration;
 using JsonApiDotNetCore.Diagnostics;
 using JsonApiDotNetCore.Errors;
@@ -30,11 +31,12 @@ public class JsonApiResourceService<TResource, TId> : IResourceService<TResource
     private readonly TraceLogWriter<JsonApiResourceService<TResource, TId>> _traceWriter;
     private readonly IJsonApiRequest _request;
     private readonly IResourceChangeTracker<TResource> _resourceChangeTracker;
+    private readonly IVersionTracker _versionTracker;
     private readonly IResourceDefinitionAccessor _resourceDefinitionAccessor;
 
     public JsonApiResourceService(IResourceRepositoryAccessor repositoryAccessor, IQueryLayerComposer queryLayerComposer, IPaginationContext paginationContext,
         IJsonApiOptions options, ILoggerFactory loggerFactory, IJsonApiRequest request, IResourceChangeTracker<TResource> resourceChangeTracker,
-        IResourceDefinitionAccessor resourceDefinitionAccessor)
+        IVersionTracker versionTracker, IResourceDefinitionAccessor resourceDefinitionAccessor)
     {
         ArgumentGuard.NotNull(repositoryAccessor);
         ArgumentGuard.NotNull(queryLayerComposer);
@@ -43,6 +45,7 @@ public JsonApiResourceService(IResourceRepositoryAccessor repositoryAccessor, IQ
         ArgumentGuard.NotNull(loggerFactory);
         ArgumentGuard.NotNull(request);
         ArgumentGuard.NotNull(resourceChangeTracker);
+        ArgumentGuard.NotNull(versionTracker);
         ArgumentGuard.NotNull(resourceDefinitionAccessor);
 
         _repositoryAccessor = repositoryAccessor;
@@ -51,6 +54,7 @@ public JsonApiResourceService(IResourceRepositoryAccessor repositoryAccessor, IQ
         _options = options;
         _request = request;
         _resourceChangeTracker = resourceChangeTracker;
+        _versionTracker = versionTracker;
         _resourceDefinitionAccessor = resourceDefinitionAccessor;
         _traceWriter = new TraceLogWriter<JsonApiResourceService<TResource, TId>>(loggerFactory);
     }
@@ -226,7 +230,8 @@ private async Task RetrieveResourceCountForNonPrimaryEndpointAsync(TId id, HasMa
             throw;
         }
 
-        TResource resourceFromDatabase = await GetPrimaryResourceByIdAsync(resourceForDatabase.Id, TopFieldSelection.WithAllAttributes, cancellationToken);
+        TResource resourceFromDatabase =
+            await GetPrimaryResourceAfterWriteAsync(resourceForDatabase.Id, TopFieldSelection.WithAllAttributes, cancellationToken);
 
         _resourceChangeTracker.SetFinallyStoredAttributeValues(resourceFromDatabase);
 
@@ -477,7 +482,7 @@ private async Task<TResource> GetForHasManyUpdateAsync(HasManyAttribute hasManyR
             throw;
         }
 
-        TResource afterResourceFromDatabase = await GetPrimaryResourceByIdAsync(id, TopFieldSelection.WithAllAttributes, cancellationToken);
+        TResource afterResourceFromDatabase = await GetPrimaryResourceAfterWriteAsync(id, TopFieldSelection.WithAllAttributes, cancellationToken);
 
         _resourceChangeTracker.SetFinallyStoredAttributeValues(afterResourceFromDatabase);
 
@@ -522,6 +527,11 @@ public virtual async Task SetRelationshipAsync(TId leftId, string relationshipNa
             AssertIsNotResourceVersionMismatch(exception);
             throw;
         }
+
+        if (_versionTracker.RequiresVersionTracking())
+        {
+            await GetPrimaryResourceAfterWriteAsync(leftId, TopFieldSelection.OnlyIdAttribute, cancellationToken);
+        }
     }
 
     /// <inheritdoc />
@@ -614,6 +624,24 @@ protected async Task<TResource> GetPrimaryResourceByIdAsync(TId id, TopFieldSele
         return primaryResources.SingleOrDefault();
     }
 
+    private async Task<TResource> GetPrimaryResourceAfterWriteAsync(TId id, TopFieldSelection fieldSelection, CancellationToken cancellationToken)
+    {
+        AssertPrimaryResourceTypeInJsonApiRequestIsNotNull(_request.PrimaryResourceType);
+
+        if (_versionTracker.RequiresVersionTracking())
+        {
+            QueryLayer queryLayer = _queryLayerComposer.ComposeForGetVersionsAfterWrite(id, _request.PrimaryResourceType, fieldSelection);
+            IReadOnlyCollection<TResource> primaryResources = await _repositoryAccessor.GetAsync<TResource>(queryLayer, cancellationToken);
+            TResource? primaryResource = primaryResources.SingleOrDefault();
+            AssertPrimaryResourceExists(primaryResource);
+
+            _versionTracker.CaptureVersions(_request.PrimaryResourceType, primaryResource);
+            return primaryResource;
+        }
+
+        return await GetPrimaryResourceByIdAsync(id, fieldSelection, cancellationToken);
+    }
+
     protected async Task<TResource> GetPrimaryResourceForUpdateAsync(TId id, CancellationToken cancellationToken)
     {
         AssertPrimaryResourceTypeInJsonApiRequestIsNotNull(_request.PrimaryResourceType);

test/DiscoveryTests/PrivateResourceService.cs

@@ -1,4 +1,5 @@
 using JetBrains.Annotations;
+using JsonApiDotNetCore.AtomicOperations;
 using JsonApiDotNetCore.Configuration;
 using JsonApiDotNetCore.Middleware;
 using JsonApiDotNetCore.Queries;
@@ -14,8 +15,9 @@ public sealed class PrivateResourceService : JsonApiResourceService<PrivateResou
 {
     public PrivateResourceService(IResourceRepositoryAccessor repositoryAccessor, IQueryLayerComposer queryLayerComposer, IPaginationContext paginationContext,
         IJsonApiOptions options, ILoggerFactory loggerFactory, IJsonApiRequest request, IResourceChangeTracker<PrivateResource> resourceChangeTracker,
-        IResourceDefinitionAccessor resourceDefinitionAccessor)
-        : base(repositoryAccessor, queryLayerComposer, paginationContext, options, loggerFactory, request, resourceChangeTracker, resourceDefinitionAccessor)
+        IVersionTracker versionTracker, IResourceDefinitionAccessor resourceDefinitionAccessor)
+        : base(repositoryAccessor, queryLayerComposer, paginationContext, options, loggerFactory, request, resourceChangeTracker, versionTracker,
+            resourceDefinitionAccessor)
     {
     }
 }

test/DiscoveryTests/ServiceDiscoveryFacadeTests.cs

@@ -1,4 +1,5 @@
 using FluentAssertions;
+using JsonApiDotNetCore.AtomicOperations;
 using JsonApiDotNetCore.Configuration;
 using JsonApiDotNetCore.Middleware;
 using JsonApiDotNetCore.Queries;
@@ -36,6 +37,7 @@ public ServiceDiscoveryFacadeTests()
         _services.AddScoped(_ => new Mock<ITargetedFields>().Object);
         _services.AddScoped(_ => new Mock<IResourceGraph>().Object);
         _services.AddScoped(typeof(IResourceChangeTracker<>), typeof(ResourceChangeTracker<>));
+        _services.AddScoped(_ => new Mock<IVersionTracker>().Object);
         _services.AddScoped(_ => new Mock<IResourceFactory>().Object);
         _services.AddScoped(_ => new Mock<IPaginationContext>().Object);
         _services.AddScoped(_ => new Mock<IQueryLayerComposer>().Object);