RestSharp serialization to JSON, object is not using SerializeAs attribute as expected

Question

I am using RestSharp (version 104.4 via NuGet) to make calls to a Rest Web Service. I have designed a set of objects (POCO) which matches resources exposed in the API. However, my objects property names does not match those expected by the Rest Service when posting data, so I would like to "transform" them when I make a request to the Rest service to make them match match. I read that adding SerializeAs attribute (with a Name specified) on my POCO's property will make them serialize correctly, but it won't.

My POCO

Imports RestSharp.Serializers

<Serializable(), SerializeAs(Name:="ApiMember")>
Public Class ApiMember
    <SerializeAs(Name:="id")>
    Public Property Id As Integer?

    <SerializeAs(Name:="email")>
    Public Property EmailAddress As String

    <SerializeAs(Name:="firstname")>
    Public Property Firstname As String

    <SerializeAs(Name:="lastname")>
    Public Property Lastname As String
End Class

My Call to the API

Dim request As RestRequest = New RestRequest(Method.POST)
Dim member As ApiMember = new ApiMember()

member.EmailAddress = "me@example.com"

request.Resource = "members"
request.RequestFormat = DataFormat.Json
request.AddBody(member)

Dim client As RestClient = New RestClient()
client.BaseUrl = "http://url.com"
client.Authenticator = New HttpBasicAuthenticator("username", "password")
client.Execute(Of ApiGenericResponse)(request)

What ends up being posted

{"Id":null,"EmailAddress":"me@example.com","Firstname":null,"Lastname":null}

Notice the name of the properties does not match thoses I specified in SerializeAs (uppercases, name of EmailAddress)

Am I missing something ?

Answer 1

This is for @MaxiWheat and anyone else interested in how to use JSON.NET as the JSON serializer in a RestSharp request. Basically, I used the approach described in this blog post by Patrick Riley:

// create the request
var request = new RestRequest(yourUrlHere, Method.POST) { RequestFormat = DataFormat.Json };

// attach the JSON.NET serializer for RestSharp
restRequest.JsonSerializer = new RestSharpJsonNetSerializer();

and the RestSharpJsonNetSerializer is an implementation (less than 100 lines of code) from the JSON.NET guys (John Sheehan) that can be found on their Github pages

With this setup, my problems went away and I was able to have a proper DTO with nice CamelCase properties, while the serialized JSON uses them in all "lowercase".

Answer 2

In RestSharp 104.4, the default JsonSerializer doesn't use the [SerializeAs] attribute, as seen by reviewing the source code.

One workaround to this is to create a custom serializer that uses the Json.NET JsonSerializer (a good example is here) and then decorate your properties with the [JsonProperty] attribute, like so:

<JsonProperty("email")>
Public Property EmailAddress As String

Answer 3

I came across this issue, and solved this a slightly different way than above, wanted to note it here.

We have a factory class that builds all of our requests. Looks like the following

public IRestRequest CreatePutRequest<TBody>(string resource, TBody body)
{
    var request = new RestRequest(resource)
    {
        Method = Method.PUT,
    };

    request.AddParameter("application/json", Serialize(body), ParameterType.RequestBody);
    return request;
}

Rather than use the AddJsonBody and AddBody methods against the request, both of which cause serialisation, I used AddParameter which will add the object you pass in without serialisation. I created a method called Serialise, which uses JSON.net to serialise our class.

private object Serialize<T>(T item)
{
    return JsonConvert.SerializeObject(item);
}

This then allows us to use JSON.net's JsonProperty annotation above your propertys. Here is an example -

public class Example
{

    [JsonProperty(PropertyName = "name")]
    public string Name { get; set; }

    [JsonProperty(PropertyName = "created")]
    public DateTime Created { get; set; }

    [JsonProperty(PropertyName = "updated")]
    public DateTime Updated { get; set; }

}

Answer 4

RestSharp uses SimpleJson. This library doesn't know or respect the [SerializeAs] attribute (which is XML-only anyway), it just outputs the POCO's property name, unless it's compiled with #SIMPLE_JSON_DATACONTRACT defined, then you can use the [DataContract] attribute to rename properties.

So your options seem to be to recompile the SimpleJson library with that define and decorate your properties with the [DataContract(Name="lowercasepropertyname")] attribute, or create a custom serializer that uses a JSON serializer that does respect other attributes as suggested in @Ryan's answer.