JsonProperty - Use different name for deserialization, but use original name for serialization?

Question

I am retrieving JSON from an API. I am using newtonsoft (this is json.net right?) to deserialize this into a list of objects. It works.

Unfortunately I also need to pass this along to someone else as JSON (they can't call the API directly only I have access to it). I say unfortunately because I need to OUTPUT my JSON that is different from what is being received (the property names need to be different).

For example, I have a class called Person, with a property called Name. I want to get "People", so I make my request to that API to get JSON as above, and get back a list of Person. Unfortunately the API doesn't return me people with Name properties, it returns me pname. So to map this, I just do:

 [JsonProperty("pname")]

This is all well and good - it converts pname to name and my class now has the value! I have a list of people with names.

Now I need to give this list of objects BACK to someone else as "Name", However when I serialize my people class back to JSON, it writes out the JSON as "pname" when I really want to write it out as "Name". I suspect it's picking up the "JsonProperty".

Is there a way to just have it use pname for deserialization, but use the original property value for serialization?

Thanks!

Answer 1

You can create a custom contract resolver that sets the property names back to the ones you've defined in the C# class before serilization. Below is some example code;

class OriginalNameContractResolver : DefaultContractResolver
{
    protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
    {
        // Let the base class create all the JsonProperties 
        IList<JsonProperty> list = base.CreateProperties(type, memberSerialization);

        // assign the C# property name
        foreach (JsonProperty prop in list)
        {
            prop.PropertyName = prop.UnderlyingName;
        }

        return list;
    }
}

Use it like this;

    JsonSerializerSettings settings = new JsonSerializerSettings();
    settings.Formatting = Formatting.Indented;
    if (useLongNames)
    {
        settings.ContractResolver = new OriginalNameContractResolver();
    }

    string response = JsonConvert.SerializeObject(obj, settings);