JADNC: Required Input validation disabled for partial patching / relationships

src/Examples/JsonApiDotNetCoreExample/Models/Article.cs

@@ -1,12 +1,14 @@
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations.Schema;
 using JsonApiDotNetCore.Models;
+using JsonApiDotNetCore.Models.CustomValidators;
 
 namespace JsonApiDotNetCoreExample.Models
 {
     public sealed class Article : Identifiable
     {
         [Attr]
+        [Required(AllowEmptyStrings = true)]
         public string Name { get; set; }
 
         [HasOne]

src/Examples/JsonApiDotNetCoreExample/Models/Author.cs

@@ -1,11 +1,13 @@
 using JsonApiDotNetCore.Models;
 using System.Collections.Generic;
+using JsonApiDotNetCore.Models.CustomValidators;
 
 namespace JsonApiDotNetCoreExample.Models
 {
     public sealed class Author : Identifiable
     {
         [Attr]
+        [Required(AllowEmptyStrings = true)]
         public string Name { get; set; }
 
         [HasMany]

src/Examples/ReportsExample/ReportsExample.csproj

@@ -8,6 +8,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="$(NpgsqlPostgreSQLVersion)" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="3.1.5" />
+    <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="3.1.4" />
   </ItemGroup>
 </Project>

src/JsonApiDotNetCore/Formatters/JsonApiReader.cs

@@ -47,6 +47,7 @@ public async Task<InputFormatterResult> ReadAsync(InputFormatterContext context)
             object model;
             try
             {
+                _deserializer.Context = context;
                 model = _deserializer.Deserialize(body);
             }
             catch (InvalidRequestBodyException exception)

src/JsonApiDotNetCore/JsonApiDotNetCore.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <VersionPrefix>4.0.0</VersionPrefix>
     <TargetFramework>$(NetCoreAppVersion)</TargetFramework>

src/JsonApiDotNetCore/Models/CustomValidators/RequiredIfEnabled.cs

@@ -0,0 +1,29 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+using System.ComponentModel.DataAnnotations;
+
+namespace JsonApiDotNetCore.Models.CustomValidators
+{
+    public class Required : RequiredAttribute
+    {
+        private bool Disabled { get; set; }
+
+        public override bool IsValid(object value)
+        {
+            return Disabled || base.IsValid(value);
+        }
+
+        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
+        {
+            CheckDisableKey(validationContext);
+            return Disabled ? ValidationResult.Success : base.IsValid(value, validationContext);
+        }
+
+        private void CheckDisableKey(ValidationContext validationContext)
+        {
+            var httpContextAccessor = (IHttpContextAccessor)validationContext.GetRequiredService(typeof(IHttpContextAccessor));
+            Disabled = httpContextAccessor.HttpContext.Items.ContainsKey($"DisableValidation_{validationContext.ObjectType.Name}_{validationContext.MemberName}") 
+                       || httpContextAccessor.HttpContext.Items.ContainsKey($"DisableValidation_{validationContext.ObjectType.Name}_Relation");
+        }
+    }
+}

src/JsonApiDotNetCore/Serialization/Common/BaseDocumentParser.cs

@@ -12,15 +12,19 @@
 using JsonApiDotNetCore.Serialization.Server;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
+using Microsoft.AspNetCore.Mvc.Formatters;
+using Required = JsonApiDotNetCore.Models.CustomValidators.Required;
 
 namespace JsonApiDotNetCore.Serialization
 {
     /// <summary>
     /// Abstract base class for deserialization. Deserializes JSON content into <see cref="Document"/>s
     /// And constructs instances of the resource(s) in the document body.
     /// </summary>
-    public abstract class BaseDocumentParser
+    public abstract class BaseDocumentParser : IJsonApiDeserializer
     {
+        public InputFormatterContext Context { get; set; }
+
         protected readonly IResourceContextProvider _contextProvider;
         protected readonly IResourceFactory _resourceFactory;
         protected Document _document;
@@ -46,7 +50,7 @@ protected BaseDocumentParser(IResourceContextProvider contextProvider, IResource
         protected abstract void AfterProcessField(IIdentifiable entity, IResourceField field, RelationshipEntry data = null);
 
         /// <inheritdoc/>
-        protected object Deserialize(string body)
+        public object Deserialize(string body)
         {
             var bodyJToken = LoadJToken(body);
             _document = bodyJToken.ToObject<Document>();
@@ -71,21 +75,38 @@ protected object Deserialize(string body)
         /// <returns></returns>
         protected IIdentifiable SetAttributes(IIdentifiable entity, Dictionary<string, object> attributeValues, List<AttrAttribute> attributes)
         {
-            if (attributeValues == null || attributeValues.Count == 0)
-                return entity;
-
             foreach (var attr in attributes)
             {
-                if (attributeValues.TryGetValue(attr.PublicAttributeName, out object newValue))
+                if (attributeValues == null || attributeValues.Count == 0)
                 {
-                    var convertedValue = ConvertAttrValue(newValue, attr.PropertyInfo.PropertyType);
-                    attr.SetValue(entity, convertedValue);
-                    AfterProcessField(entity, attr);
+                    if (Context == null || Context.HttpContext.Request.Method != "PATCH") continue;
+                    if (attr.PropertyInfo.GetCustomAttribute<Required>() != null)
+                    {
+                        DisableValidator(attr.PropertyInfo.ReflectedType?.Name, attr.PropertyInfo.Name);
+                    }
+                }
+                else
+                {
+                    if (attributeValues.TryGetValue(attr.PublicAttributeName, out object newValue))
+                    {
+                        var convertedValue = ConvertAttrValue(newValue, attr.PropertyInfo.PropertyType);
+                        attr.SetValue(entity, convertedValue);
+                        AfterProcessField(entity, attr);
+                    }
+                    else
+                    {
+                        if (Context == null || Context.HttpContext.Request.Method != "PATCH") continue;
+                        if (attr.PropertyInfo.GetCustomAttribute<Required>() != null)
+                        {
+                            DisableValidator(attr.PropertyInfo.ReflectedType?.Name, attr.PropertyInfo.Name);
+                        }
+                    }
                 }
             }
 
             return entity;
         }
+
         /// <summary>
         /// Sets the relationships on a parsed entity
         /// </summary>
@@ -101,14 +122,15 @@ protected IIdentifiable SetRelationships(IIdentifiable entity, Dictionary<string
             var entityProperties = entity.GetType().GetProperties();
             foreach (var attr in relationshipAttributes)
             {
+                DisableValidator(attr.PropertyInfo.Name, "Relation");
+
                 if (!relationshipsValues.TryGetValue(attr.PublicRelationshipName, out RelationshipEntry relationshipData) || !relationshipData.IsPopulated)
                     continue;
 
                 if (attr is HasOneAttribute hasOneAttribute)
                     SetHasOneRelationship(entity, entityProperties, hasOneAttribute, relationshipData);
                 else
                     SetHasManyRelationship(entity, (HasManyAttribute)attr, relationshipData);
-
             }
             return entity;
         }
@@ -260,5 +282,15 @@ private object DeserializeComplexType(JContainer obj, Type targetType)
         {
             return obj.ToObject(targetType);
         }
+
+        private void DisableValidator(string model, string name)
+        {
+            if (Context == null) return;
+            var itemKey = $"DisableValidation_{model}_{name}";
+            if (!Context.HttpContext.Items.ContainsKey(itemKey))
+            {
+                Context.HttpContext.Items.Add(itemKey, true);
+            }
+        }
     }
 }

src/JsonApiDotNetCore/Serialization/Server/Contracts/IJsonApiDeserializer.cs

@@ -1,4 +1,5 @@
 using JsonApiDotNetCore.Models;
+using Microsoft.AspNetCore.Mvc.Formatters;
 
 namespace JsonApiDotNetCore.Serialization.Server
 {
@@ -7,6 +8,7 @@ namespace JsonApiDotNetCore.Serialization.Server
     /// </summary>
     public interface IJsonApiDeserializer
     {
+        public InputFormatterContext Context { get; set; }
         /// <summary>
         /// Deserializes JSON in to a <see cref="Document"/> and constructs entities
         /// from <see cref="ExposableData{T}.Data"/>.

src/JsonApiDotNetCore/Serialization/Server/RequestDeserializer.cs

@@ -1,4 +1,3 @@
-using System;
 using JsonApiDotNetCore.Exceptions;
 using JsonApiDotNetCore.Internal;
 using JsonApiDotNetCore.Internal.Contracts;
@@ -9,7 +8,7 @@ namespace JsonApiDotNetCore.Serialization.Server
     /// <summary>
     /// Server deserializer implementation of the <see cref="BaseDocumentParser"/>
     /// </summary>
-    public class RequestDeserializer : BaseDocumentParser, IJsonApiDeserializer
+    public class RequestDeserializer : BaseDocumentParser
     {
         private readonly ITargetedFields  _targetedFields;
 

test/JsonApiDotNetCoreExampleTests/Acceptance/ManyToManyTests.cs

@@ -294,6 +294,10 @@ public async Task Can_Create_Many_To_Many()
                 data = new
                 {
                     type = "articles",
+                    attributes = new Dictionary<string, object>
+                    {
+                        {"name", "An article with relationships"}
+                    },
                     relationships = new Dictionary<string, dynamic>
                     {
                         {  "author",  new {