Azure WebApi JsonSerializerSettings behaving differently

Question

On Thursday, 12/14 before 1:15pm CST, JSON serialization/deserialization behaved as expected on my Azure WebApi service. However, after that time, it seems as though our setting in the WebApiConfig.cs's Register method:

JsonConvert.DefaultSettings = () => new JsonSerializerSettings
{
    NullValueHandling = NullValueHandling.Ignore
};

seems to be ignored, and now, when we serialize to json, we're getting properties with null values.

We're using .Net Framework 4.8.

On another, pre-production, instance of our service, that setting still seems to be respected, so we don't see properties serialized that have null values.

We had no changes to the service around that time, so it seems to be an infrastructure change.

What types of changes could have been made that would change the behavior of this setting?

Answer 1

@Mark Johnson With it being the holiday season, there are not any infrastructure patches allowed during this time unless they are security related or a hot fix. Even then, those have to be business critical for them to be approved. It would be highly unlikely there has been an infrastructure change in the middle of our no updates window.

One thing you can try is to explicitly set the NullValueHandling property on the JsonSerializerSettings object that you pass to the JsonConvert.SerializeObject method. This will ensure that the NullValueHandling setting is applied during serialization, regardless of the value of the JsonConvert.DefaultSettings property.

For example:

var settings = new JsonSerializerSettings
{
    NullValueHandling = NullValueHandling.Ignore
};

var json = JsonConvert.SerializeObject(obj, settings);

If this doesn't solve the issue, you can try checking the version of the Newtonsoft.Json package that your project is using. It's possible that an update to the package has caused a behavior change. You can try downgrading to a previous version of the package to see if that resolves the issue.

Finally, you can try enabling tracing in your Azure WebApi service to see if there are any errors or warnings related to JSON serialization/deserialization. This can help you identify the root cause of the issue.