Error on deserialize json to Either<string, T>

[josercf]

I tried use a Either<string, T> as property of a view model in one web api with .NET CORE 3.0

When I sent a string as value of the property, it deserialize correctly, but when property values is an any T, the Either type identify as TRight correctly but can't deserialize it.

*When I set the same data directly from code C# it's works correctly

Below I pasted some evidencies of this issue

csproj
Microsoft.Net.Compilers Version="3.3.1"
System.ValueTuple Version="4.5.0"
Tango Version="3.1.2"

View Model
`public class SampleRequestModel
{
[JsonProperty("option")]
public int Option{ get; set; }

    [JsonProperty("payload")]
    public Either<string, Location> Payload { get; set; }
}

public class Location
{
    [JsonProperty("latitude")]
    public double Latitude { get; set; }

    [JsonProperty("longitude")]
    public double Longitude { get; set; }
}`

Controller

`[Route("api/[controller]")]
[ApiController]
public class ValuesController : ControllerBase
{
public async Task Post([FromBody] SampleRequestModel model)
{
string filter = string.Empty;

        Location location = model.Payload.Match(
             (payload) =>
             {
                 return payload;
             },
             (text) =>
             {
                 filter = text;
                 return default;
             });

        return Ok(new { location, filter});
    }
}`

Request

1 - Works
curl -X POST
http://localhost:50535/api/values
-H 'Accept: /'
-H 'Accept-Encoding: gzip, deflate'
-H 'Cache-Control: no-cache'
-H 'Connection: keep-alive'
-H 'Content-Length: 36'
-H 'Content-Type: application/json'
-H 'Host: localhost:50535'
-H 'Postman-Token: 45c3d866-2cd1-4266-8364-b22dd6aa8283,660d6618-8e8d-4ef5-983b-00ee0e6bb9a9'
-H 'User-Agent: PostmanRuntime/7.20.1'
-H 'cache-control: no-cache'
-d '{
"option": 1,
"payload": "jose"
}'

2- Dont work
curl -X POST
http://localhost:50535/api/values
-H 'Accept: /'
-H 'Accept-Encoding: gzip, deflate'
-H 'Cache-Control: no-cache'
-H 'Connection: keep-alive'
-H 'Content-Length: 36'
-H 'Content-Type: application/json'
-H 'Host: localhost:50535'
-H 'Postman-Token: 45c3d866-2cd1-4266-8364-b22dd6aa8283,0a834c05-a2d6-4faf-81e7-5ea53e6a4a3d'
-H 'User-Agent: PostmanRuntime/7.20.1'
-H 'cache-control: no-cache'
-d '{
"option": 1,
"payload": {
"latitude": 23.123,
"longitude": 48.334
}
}'

[LeonardoPrange]

Hello, it may have been a mistake typing here in Issue but I see your JsonProperty is ("loongitude") and in payload this "longitude", can you check if this is the problem?

[josercf]

Hi!
I have make a mistake on type the code here. The deserialization doesn't occurs correctly. I think that the model binder provider doesn't know create a instance of Either type

[LeonardoPrange]

Model Binder has its limitations, and the Either type is very complex for it to convert correctly, I think that to resolve it would be to change the payload to a simpler class and do the conversion later.