For convenience, expose the resource context that matches TResource in JsonApiResourceDefinition.

Author: Bart Koelman

src/JsonApiDotNetCore/Resources/JsonApiResourceDefinition.cs

@@ -37,11 +37,17 @@ public class JsonApiResourceDefinition<TResource, TId> : IResourceDefinition<TRe
     {
         protected IResourceGraph ResourceGraph { get; }
 
+        /// <summary>
+        /// Provides metadata for the resource type <typeparamref name="TResource" />.
+        /// </summary>
+        protected ResourceContext ResourceContext { get; }
+
         public JsonApiResourceDefinition(IResourceGraph resourceGraph)
         {
             ArgumentGuard.NotNull(resourceGraph, nameof(resourceGraph));
 
             ResourceGraph = resourceGraph;
+            ResourceContext = resourceGraph.GetResourceContext<TResource>();
         }
 
         /// <inheritdoc />

test/JsonApiDotNetCoreExampleTests/IntegrationTests/Archiving/TelevisionBroadcastDefinition.cs

@@ -24,7 +24,6 @@ public sealed class TelevisionBroadcastDefinition : JsonApiResourceDefinition<Te
         private readonly TelevisionDbContext _dbContext;
         private readonly IJsonApiRequest _request;
         private readonly IEnumerable<IQueryConstraintProvider> _constraintProviders;
-        private readonly ResourceContext _broadcastContext;
 
         private DateTimeOffset? _storedArchivedAt;
 
@@ -35,7 +34,6 @@ public TelevisionBroadcastDefinition(IResourceGraph resourceGraph, TelevisionDbC
             _dbContext = dbContext;
             _request = request;
             _constraintProviders = constraintProviders;
-            _broadcastContext = resourceGraph.GetResourceContext<TelevisionBroadcast>();
         }
 
         public override FilterExpression OnApplyFilter(FilterExpression existingFilter)
@@ -46,8 +44,7 @@ public override FilterExpression OnApplyFilter(FilterExpression existingFilter)
 
                 if (IsReturningCollectionOfTelevisionBroadcasts() && !HasFilterOnArchivedAt(existingFilter))
                 {
-                    AttrAttribute archivedAtAttribute =
-                        _broadcastContext.Attributes.Single(attr => attr.Property.Name == nameof(TelevisionBroadcast.ArchivedAt));
+                    AttrAttribute archivedAtAttribute = ResourceContext.Attributes.Single(attr => attr.Property.Name == nameof(TelevisionBroadcast.ArchivedAt));
 
                     var archivedAtChain = new ResourceFieldChainExpression(archivedAtAttribute);
 
@@ -71,7 +68,7 @@ private bool IsRequestingCollectionOfTelevisionBroadcasts()
         {
             if (_request.IsCollection)
             {
-                if (_request.PrimaryResource == _broadcastContext || _request.SecondaryResource == _broadcastContext)
+                if (_request.PrimaryResource == ResourceContext || _request.SecondaryResource == ResourceContext)
                 {
                     return true;
                 }
@@ -97,7 +94,7 @@ private bool IsIncludingCollectionOfTelevisionBroadcasts()
 
             foreach (IncludeElementExpression includeElement in includeElements)
             {
-                if (includeElement.Relationship is HasManyAttribute && includeElement.Relationship.RightType == _broadcastContext.ResourceType)
+                if (includeElement.Relationship is HasManyAttribute && includeElement.Relationship.RightType == ResourceContext.ResourceType)
                 {
                     return true;
                 }

test/JsonApiDotNetCoreExampleTests/IntegrationTests/ResourceDefinitions/Reading/MoonDefinition.cs

@@ -35,10 +35,8 @@ public override IReadOnlyCollection<IncludeElementExpression> OnApplyIncludes(IR
                 return existingIncludes;
             }
 
-            ResourceContext resourceContext = ResourceGraph.GetResourceContext<Moon>();
-
             RelationshipAttribute orbitsAroundRelationship =
-                resourceContext.Relationships.Single(relationship => relationship.Property.Name == nameof(Moon.OrbitsAround));
+                ResourceContext.Relationships.Single(relationship => relationship.Property.Name == nameof(Moon.OrbitsAround));
 
             return new List<IncludeElementExpression>(existingIncludes)
             {

test/JsonApiDotNetCoreExampleTests/IntegrationTests/ResourceDefinitions/Reading/PlanetDefinition.cs

@@ -50,8 +50,7 @@ public override FilterExpression OnApplyFilter(FilterExpression existingFilter)
 
             if (_clientSettingsProvider.ArePlanetsWithPrivateNameHidden)
             {
-                ResourceContext resourceContext = ResourceGraph.GetResourceContext<Planet>();
-                AttrAttribute privateNameAttribute = resourceContext.Attributes.Single(attribute => attribute.Property.Name == nameof(Planet.PrivateName));
+                AttrAttribute privateNameAttribute = ResourceContext.Attributes.Single(attribute => attribute.Property.Name == nameof(Planet.PrivateName));
 
                 FilterExpression hasNoPrivateName = new ComparisonExpression(ComparisonOperator.Equals, new ResourceFieldChainExpression(privateNameAttribute),
                     new NullConstantExpression());