json-serialization-5.cs

public class MyApiControllerAttribute : ActionFilterAttribute
{
    /// <inheritdoc/>
    public override void OnActionExecuted(ActionExecutedContext ctx)
    {
        if (ctx.Result is ObjectResult objectResult)
        {
            // Create options to match the CMS delivery API, along with any customizations we want for Forms.
            var options = new JsonSerializerOptions
            {
                DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
                DictionaryKeyPolicy = JsonNamingPolicy.CamelCase,
                PropertyNamingPolicy = JsonNamingPolicy.CamelCase,

                // Output properties in alphabetical order.
                // Hat-tip: https://stackoverflow.com/a/72593993
                TypeInfoResolver = new DefaultJsonTypeInfoResolver
                {
                    Modifiers = { AlphabetizeProperties() },
                },
            };
            options.Converters.Add(new JsonStringEnumConverter());
            objectResult.Formatters.Add(new SystemTextJsonOutputFormatter(options));
        }
    }

    private static Action<JsonTypeInfo> AlphabetizeProperties(Type type) =>
        typeInfo =>
            {
                if (typeInfo.Kind != JsonTypeInfoKind.Object || !type.IsAssignableFrom(typeInfo.Type))
                {
                    return;
                }

                AlphabetizeProperties()(typeInfo);
            };

    private static Action<JsonTypeInfo> AlphabetizeProperties() =>
        static typeInfo =>
            {
                if (typeInfo.Kind != JsonTypeInfoKind.Object)
                {
                    return;
                }

                var properties = typeInfo.Properties.OrderBy(p => p.Name, StringComparer.Ordinal).ToList();
                typeInfo.Properties.Clear();
                for (int i = 0; i < properties.Count; i++)
                {
                    properties[i].Order = i;
                    typeInfo.Properties.Add(properties[i]);
                }
            };
}