Ignoring specific data type when serializing with Json.NET?

Question

I'm saving JSON objects into the database, sometimes it grows very large (I have an object of length 205,797 characters) I want to eliminate the size as possible as I can. these objects have a lot of GUID fields, all I don't need, It may help eliminating the size if there is a way to ignore any GUID type from serializing.

This is my code, I pass an object of any model type in my application:

 public static string GetEntityAsJson(object entity)
 {
     var json = JsonConvert.SerializeObject(entity, Formatting.None, new JsonSerializerSettings
     {
         ReferenceLoopHandling = ReferenceLoopHandling.Ignore
     });
     return json;
}

EDIT

I don't want to use JsonIgnore attribute, as I will have to add it to so many classes each has a lot of GUID properties, I'm looking for something straight forward like: IgnoreDataType = DataTypes.GUID

Answer 1

You can use a custom ContractResolver to ignore all properties of a specific data type in all classes. For example, here is one that ignores all Guids:

class IgnoreGuidsResolver : DefaultContractResolver
{
    protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
    {
        JsonProperty prop = base.CreateProperty(member, memberSerialization);
        if (prop.PropertyType == typeof(Guid))
        {
            prop.Ignored = true;
        }
        return prop;
    }
}

To use the resolver, just add it to your JsonSerializerSettings:

var json = JsonConvert.SerializeObject(entity, Formatting.None, new JsonSerializerSettings
{
    ContractResolver = new IgnoreGuidsResolver(),
    ...
});

Demo fiddle: https://dotnetfiddle.net/lOOUfq