Fixed: Paging links should not be rendered in POST response.

src/JsonApiDotNetCore/Middleware/JsonApiMiddleware.cs

@@ -183,7 +183,8 @@ private static void SetupRequest(JsonApiRequest request, ResourceContext primary
                 }
             }
 
-            request.IsCollection = request.PrimaryId == null || request.Relationship is HasManyAttribute;
+            var isGetAll = request.PrimaryId == null && request.IsReadOnly;
+            request.IsCollection = isGetAll || request.Relationship is HasManyAttribute;
         }
 
         private static string GetPrimaryRequestId(RouteValueDictionary routeValues)

test/JsonApiDotNetCoreExampleTests/IntegrationTests/ReadWrite/Creating/CreateResourceTests.cs

@@ -56,6 +56,9 @@ public async Task Sets_location_header_for_created_resource()
             var newWorkItemId = responseDocument.SingleData.Id;
             httpResponse.Headers.Location.Should().Be("/workItems/" + newWorkItemId);
 
+            responseDocument.Links.Self.Should().Be("http://localhost/workItems");
+            responseDocument.Links.First.Should().BeNull();
+
             responseDocument.SingleData.Should().NotBeNull();
             responseDocument.SingleData.Links.Self.Should().Be("http://localhost" + httpResponse.Headers.Location);
         }

test/UnitTests/Middleware/JsonApiRequestTests.cs

@@ -0,0 +1,105 @@
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using FluentAssertions;
+using JsonApiDotNetCore.Configuration;
+using JsonApiDotNetCore.Middleware;
+using JsonApiDotNetCoreExample.Models;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http.Features;
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+using Xunit;
+
+namespace UnitTests.Middleware
+{
+    public sealed class JsonApiRequestTests
+    {
+        [Theory]
+        [InlineData("GET", "/articles", true, EndpointKind.Primary, true)]
+        [InlineData("GET", "/articles/1", false, EndpointKind.Primary, true)]
+        [InlineData("GET", "/articles/1/author", false, EndpointKind.Secondary, true)]
+        [InlineData("GET", "/articles/1/revisions", true, EndpointKind.Secondary, true)]
+        [InlineData("GET", "/articles/1/relationships/author", false, EndpointKind.Relationship, true)]
+        [InlineData("GET", "/articles/1/relationships/revisions", true, EndpointKind.Relationship, true)]
+        [InlineData("POST", "/articles", false, EndpointKind.Primary, false)]
+        [InlineData("POST", "/articles/1/relationships/revisions", true, EndpointKind.Relationship, false)]
+        [InlineData("PATCH", "/articles/1", false, EndpointKind.Primary, false)]
+        [InlineData("PATCH", "/articles/1/relationships/author", false, EndpointKind.Relationship, false)]
+        [InlineData("PATCH", "/articles/1/relationships/revisions", true, EndpointKind.Relationship, false)]
+        [InlineData("DELETE", "/articles/1", false, EndpointKind.Primary, false)]
+        [InlineData("DELETE", "/articles/1/relationships/revisions", true, EndpointKind.Relationship, false)]
+        public async Task Sets_request_properties_correctly(string requestMethod, string requestPath, bool expectIsCollection, EndpointKind expectKind, bool expectIsReadOnly)
+        {
+            // Arrange
+            var options = new JsonApiOptions
+            {
+                UseRelativeLinks = true
+            };
+
+            var graphBuilder = new ResourceGraphBuilder(options, NullLoggerFactory.Instance);
+            graphBuilder.Add<Article>();
+            graphBuilder.Add<Author>();
+            graphBuilder.Add<Revision>();
+
+            var resourceGraph = graphBuilder.Build();
+
+            var controllerResourceMappingMock = new Mock<IControllerResourceMapping>();
+
+            controllerResourceMappingMock
+                .Setup(x => x.GetAssociatedResource(It.IsAny<string>()))
+                .Returns(typeof(Article));
+
+            var httpContext = new DefaultHttpContext();
+            SetupRoutes(httpContext, requestMethod, requestPath);
+
+            var request = new JsonApiRequest();
+
+            var middleware = new JsonApiMiddleware(_ => Task.CompletedTask);
+
+            // Act
+            await middleware.Invoke(httpContext, controllerResourceMappingMock.Object, options, request, resourceGraph);
+
+            // Assert
+            request.IsCollection.Should().Be(expectIsCollection);
+            request.Kind.Should().Be(expectKind);
+            request.IsReadOnly.Should().Be(expectIsReadOnly);
+            request.BasePath.Should().BeEmpty();
+            request.PrimaryResource.Should().NotBeNull();
+            request.PrimaryResource.PublicName.Should().Be("articles");
+        }
+
+        private static void SetupRoutes(HttpContext httpContext, string requestMethod, string requestPath)
+        {
+            httpContext.Request.Method = requestMethod;
+
+            var feature = new RouteValuesFeature
+            {
+                RouteValues =
+                {
+                    ["controller"] = "theController",
+                    ["action"] = "theAction"
+                }
+            };
+
+            var pathSegments = requestPath.Split("/", StringSplitOptions.RemoveEmptyEntries);
+            if (pathSegments.Length > 1)
+            {
+                feature.RouteValues["id"] = pathSegments[1];
+
+                if (pathSegments.Length >= 3)
+                {
+                    feature.RouteValues["relationshipName"] = pathSegments.Last();
+                }
+            }
+
+            if (pathSegments.Contains("relationships"))
+            {
+                feature.RouteValues["action"] = "Relationship";
+            }
+
+            httpContext.Features.Set<IRouteValuesFeature>(feature);
+            httpContext.SetEndpoint(new Endpoint(null, new EndpointMetadataCollection(), null));
+        }
+    }
+}