Override field name deserialization in ServiceStac

问题:

I'm using ServiceStack to deserialize some HTML form values but can't figure out how to override the value that each field should be read from.

For example, the form posts a value to first_name but the property on my POCO is called FirstName. how would I do mapping like that in ServiceStack

回答1:

The ServiceStack Text serializers support [DataMember] aliases where you can use the Name parameter to specify what alias each field should be, e.g:

[DataContract]
public class Customer
{
    [DataMember(Name="first_name")]
    public string FirstName { get; set; }

    [DataMember(Name="last_name")]
    public string LastName { get; set; }
}

Note: Once you add [DataContract] / [DataMember] attributes to your DTOs then the behavior becomes opt-in and you will have add [DataMember] on each of the properties you want serialized.

Emitting idiomatic JSON for all DTOs

You can instruct JSON serialization to follow a different convention by specifying the following global settings:

//Emit {"firstName":"first","lastName":"last"}
JsConfig.Init(new Config { TextCase = TextCase.CamelCase });

//Emit {"first_name":"first","last_name":"last"}
JsConfig.Init(new Config { TextCase = TextCase.SnakeCase });

回答2:

In order to serialise C# class with underscore convention, you need to set JsConfig.EmitLowercaseUnderscoreNames to true as mythz said.

JsConfig.EmitLowercaseUnderscoreNames = true; 

But, in my experience, Deserialising would fail, as it expect CamelCased values. To enable underscore json value deserialisation, you need to set JsConfig's PropertyConvention.

JsConfig.PropertyConvention = PropertyConvention.Lenient;

I use a simple helper method to resolve the serialisation and deserialisation issue.

public static class JsonHelpers
{
    public static string ToUnderscoredJson<T>(this T obj)
    {
        JsConfig.EmitLowercaseUnderscoreNames = true;

        return JsConfig.PreferInterfaces
            ? JsonSerializer.SerializeToString(obj, AssemblyUtils.MainInterface<T>())
            : JsonSerializer.SerializeToString(obj);
    }

    public static T FromUnderscoredJson<T>(this string json)
    {
        JsConfig.PropertyConvention = PropertyConvention.Lenient;
        return JsonSerializer.DeserializeFromString<T>(json);
    }
}