Are nullable enums with dots valid in OpenAPI yaml file?

Question

The main question is that if the enum can or cannot have "." in the middle of the name, my example is the following:

So someone sent me this openapi yaml file, bellow, that i am generating a controller in c# for. This is the yaml I received:

  /actions/MyAction:
    post:
      summary: blahblah
      tags:
      - action
      parameters:
      - in: body
        name: MyAction
        required: true
        schema:
          type: object
          properties:
            data: 
              type: object
              properties:
                target:
                  type: string
                location:
                  description: thelocation
                  type: string
                  enum:
                    - location.Outdoor1
                    - location.Outdoor2
                    - location.Outdoor3

The object class generated in c# for :

 public partial class Data2
    {
        [Newtonsoft.Json.JsonProperty("target", Required = Newtonsoft.Json.Required.Default, NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore)]
        public stringTarget { get; set; }

        [Newtonsoft.Json.JsonProperty("location", Required = Newtonsoft.Json.Required.Default, NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore)]
[Newtonsoft.Json.JsonConverter(typeof(System.Text.Json.Serialization.JsonStringEnumConverter))]
public Data2Location? Location { get; set; }
    }

And for the enum i have:

public enum Data2Location
    {
        [System.Runtime.Serialization.EnumMember(Value = @"location.Outdoor1")]
        location_Outdoor1= 0,

        [System.Runtime.Serialization.EnumMember(Value = @"location.Outdoor2")]
        location_Outdoor2 = 1,

        [System.Runtime.Serialization.EnumMember(Value = @"location.Outdoor3")]
        location_Outdoor3= 2,
    }

the controller

[Microsoft.AspNetCore.Mvc.HttpPost, Microsoft.AspNetCore.Mvc.Route("actions/MyAction")]
        public Microsoft.AspNetCore.Mvc.IActionResult MyAction([Microsoft.AspNetCore.Mvc.FromBody] Data2data)
        {
            return _implementation.MyAction(data);
        }

My troubles are with the enum "thelocation" because when i send a request from Postman the all object comes null in the method above for the request: post to http://localhost:5000/api/v1/actions/Myaction With body:

{
    "data": {
        "target": "thetarget"
        "location":"location.Outdoor2"
    }
}

According to your definition, the field in the JSON body is supposed to be named `"location"` not `"thelocation"`. Also, `"location1.InHouse"` is not a valid value for this enum. — Helen, Feb 09 '21 at 07:22
That is correct @Helen, fixed that. But the question still maintains, what to do for the '.' in the enum value ´location1.Outdoor2´. Changing the char from '.' to '_' would resolve this, but the it would go against the spec. — Madax, Feb 09 '21 at 08:25
Dots are perfectly valid in enum values in OpenAPI Specification. If the correct JSON payload also results in the same problem, the problem might be with the (de)serializer and/or annotations. Maybe someone with .NET knowledge can comment on this. — Helen, Feb 09 '21 at 08:54
Right @Helen, that is a minor issue, because i masked this of a ral example... Edit: I also think it is (de)serialization problem, I am using .netcore 3.1 with the standard "System.Text.Json.Serialization" — mfabruno, Feb 09 '21 at 09:21

score 1 · Accepted Answer · edited Feb 12 '21 at 17:58

So since I didn't get any help I decided to investigate and found a workaround solution...

I think the problem is that newtonsoft is not correctly parsing nullable enums. So I did a new stringenumconverter that takes that into account when reading the JSON, since their code is open source I could do it:

public class NullableStringEnumConverter : StringEnumConverter
{
    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        try
        {
            return base.ReadJson(reader, objectType, existingValue, serializer);
        }
        catch
        {
            if (IsNullableType(objectType))
                return null;

            return base.ReadJson(reader, objectType, existingValue, serializer);
        }
    }
}

private static bool IsNullableType(Type t)
{
    if (t == null)
        throw new ArgumentNullException(nameof(t));

    return (t.IsGenericType && t.GetGenericTypeDefinition() == typeof(Nullable<>));
}

With this my location was put to "null" when it could not be found in the enum and if it found in the attribute EnumMember a string equal to the one given it worked, while the rest of the object was well parsed.

Are nullable enums with dots valid in OpenAPI yaml file?

1 Answers1