How to ignore JsonProperty(PropertyName = "someName") when serializing json?

Question

I have some C# code using ASP.Net MVC, which is making use of Json.Net to serialize some DTOs. In order to reduce payload, I have made use of the [JsonProperty(PropertyName = "shortName")] attribute to use shorter property names during serialization.

This works great when the client is another .Net app or service, as the deserialization puts the object hierarchy back together, using the longer more friendly names, while keeping actual transfer payload low.

The problem comes into play when the client is javascript/ajax through a browser. It makes the request, and gets the json ... but that json is using the shortened less-friendly names.

How can I make the json.net serialization engine ignore the [JsonProperty(PropertyName = "shortName")] attribute programmatically? Ideally, my MVC service is going to sit there running and normally serialize using the shortened property names. When my code detects a particular parameter, I'd like to get the data serialized using the longer names and ignore the [JsonProperty()] attribute.

Any suggestions?

Thanks,

Kevin

Answer 1

This can be done pretty easily using a custom contract resolver. Here's all the code you would need:

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

        // Now inspect each property and replace the 
        // short name with the real property name
        foreach (JsonProperty prop in list)
        {
            prop.PropertyName = prop.UnderlyingName;
        }

        return list;
    }
}

Here's a quick demo using the resolver:

class Program
{
    static void Main(string[] args)
    {
        Foo foo = new Foo
        {
            CustomerName = "Bubba Gump Shrimp Company",
            CustomerNumber = "BG60938"
        };

        Console.WriteLine("--- Using JsonProperty names ---");
        Console.WriteLine(Serialize(foo, false));
        Console.WriteLine();
        Console.WriteLine("--- Ignoring JsonProperty names ---");
        Console.WriteLine(Serialize(foo, true));
    }

    static string Serialize(object obj, bool useLongNames)
    {
        JsonSerializerSettings settings = new JsonSerializerSettings();
        settings.Formatting = Formatting.Indented;
        if (useLongNames)
        {
            settings.ContractResolver = new LongNameContractResolver();
        }

        return JsonConvert.SerializeObject(obj, settings);
    }
}

class Foo
{
    [JsonProperty("cust-num")]
    public string CustomerNumber { get; set; }
    [JsonProperty("cust-name")]
    public string CustomerName { get; set; }
}

Output:

--- Using JsonProperty names ---
{
  "cust-num": "BG60938",
  "cust-name": "Bubba Gump Shrimp Company"
}

--- Ignoring JsonProperty names ---
{
  "CustomerNumber": "BG60938",
  "CustomerName": "Bubba Gump Shrimp Company"
}

Answer 2

Just want to "extend" Brian's answer with Deserializer class,

static T Deserialize<T>(string json)
{
    return JsonConvert.DeserializeObject<T>(json, new JsonSerializerSettings()
    {
        ContractResolver = new LongNameContractResolver()
    });
}