Net Core 2.1 Controller truncates Json while the json has no reference loops - asp.net-core

Question

I'm struggling with net core returning truncated response. I have already defined no reference loop in my startup services, and also tried to set compatibility version for the version i'm currently using 2.1 as follows:
services.AddMvc()
.SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
.AddJsonOptions(x => x.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore);
I also tried to serialize the array using JsonConvert and it did not throw any reference loop exception. Here's the action in the controller and the serializedArray text:
public IActionResult GetProductItems(int productId)
{
try
{
var productItems = _productsMethods.GetProductItems(productId);
// for testing the object for ref loops
string serialized = Newtonsoft.Json.JsonConvert.SerializeObject(productItems);
return Ok(productItems);
}
catch (ClientException ex)
{
return BadRequest(new { message = ex.Message });
}
catch (Exception ex)
{
return StatusCode(500, new { message = ex.Message });
}
}
// serialized string
//[{"ID":2,"ProductId":6,"ItemId":4,"Product":null,"Item":null,"Orders":[]},{"ID":3,"ProductId":":6,"ItemId":1,"Product":null,"Item":null,"Orders":[]},{"ID":5,"ProductId":":6,"ItemId":2,"Product":null,"Item":null,"Orders":[]}]
Here's the actual response
[{"id":2,"productId":6,"itemId":4,"product":null,"item":null,"orders":
Method:
public List<ProductItem> GetProductItems(int productId)
{
IQueryable<DataSets.ProductItem> query = db.ProductItems
.AsNoTracking()
.Include(k => k.Orders)
.Where(k => k.ProductId == productId);
// result truncated (when array orders is empty)
//return query.Select(_mapper.Map<ProductItem>).ToList();
// without automapper, also truncated
//return query.Select(k => new ProductItem()
//{
// ID = k.ID,
// ItemId = k.ItemId,
// ProductId = k.ProductId,
// Orders = k.Orders.Select(a => new Order() { ID = a.ID })
// .ToList()
//}).ToList();
// WORKS, not getting truncated
// order not included
return query.Select(k => new ProductItem()
{
ID = k.ID,
ItemId = k.ItemId,
ProductId = k.ProductId,
}).ToList();
}
Entities (renamed and removed props for simplification):
public class Product
{
public int ID { get; set; }
// some props
public string UserId { get; set; }
public User User { get; set; }
public List<ProductItem> Items { get; set; }
}
public class ProductItem
{
public int ID { get; set; }
// some props
public int ProductId { get; set; }
public int ItemId { get; set; }
public Product Product { get; set; }
public Item Item { get; set; }
public List<Order> Orders { get; set; }
}
public class Order
{
public int ID { get; set; }
// some props
public int ItemId { get; set; }
public ProductItemOrder Item { get; set; }
}
Since there is no reference loop in orders and also the reference loop is ignored. Why is this still truncating?

Answer 1

I think the problem is public Product Product { get; set; } part here. You should define your Product entity virtually.
Here is an example below,
public class Blog
{
public int BlogId { get; set; }
public string Name { get; set; }
public string Url { get; set; }
public string Tags { get; set; }
public virtual ICollection<Post> Posts { get; set; }
}
Here is source.

Answer 2

For someone who might have this issue in the future. While I think the API should throw that error instead of just truncating the response.
I had 2 properties with the same letters but different letter case IPAddress and IpAddress.
SerializeObject alone wasn't throwing an exception, then I did this (CamelCase Resolver) to point out the issue:
Newtonsoft.Json.JsonConvert.DefaultSettings = () => new Newtonsoft.Json.JsonSerializerSettings
{
NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore,
ContractResolver = new Newtonsoft.Json.Serialization.CamelCasePropertyNamesContractResolver()
};
string serialized = Newtonsoft.Json.JsonConvert.SerializeObject(productItems);
So it threw: A member with the name 'ipAddress' already exists on ...