Is this json badly constructed? – Ebay API

After reading the documentation, I understand eBay’s approach, but I find it poor in terms of client side deserialisation. For example, the benefit of an array value for the ack property is that the value could also contain a warning, e.g.:

{
    "ack": [
        "Success",
        "Warning"
    ]
}

However, a list of strings is not ideal for client side processing (e.g. in C#, bool hasWarning = pocoList.Contains("Warning"); doesn’t strike me as completely foolproof). I’d rather have a response such as:

{
    "ack": {
        "result": "Success",
        "warning": null
    }
}

Then with my deserialised POCO, given that the value of warning is still a string, I could write this:

[DataContract]
public class Ack
{
    [DataMember(Name="result")]
    public string Result { get; set; }

    [DataMember(Name="warning")]
    public string Warning { get; set; }

    [IgnoreDataMember]
    public bool HasWarning
    {
        get { return !string.IsNullOrEmpty(Warning); }
    }
}

This would allow me to replace my previous LINQ query with bool hasWarning = ack.HasWarning;.

There are definitely places where use of arrays is completely unnecessary. The docs describe the version property as “the release version that eBay used to process the request”, thus I would return this as a single string. The array would only make sense if it was a versions property (e.g. for identifying all versions of the backend that support a specific request).

I’ve definitely seen worse JSON responses, but there are places where the APIs should ideally be returning a JSON object or a single value.