Hi,

I just write a very simple AuthorizedApiController - i simply wanted to return a node, but this seems to be a very hard challenge.

Here is my code (concerning the second function "GetNewsletterAdminNode", the first function works fine!):

using System;
using System.Web.Http;
using System.Web.Mvc;
using Umbraco.Core.Models.PublishedContent;
using Umbraco.Web;
using Umbraco.Web.Mvc;
using Umbraco.Web.WebApi;

namespace umbGastroON.Controllers.RESTApi.Authorized
{    
    [PluginController("GastroOn")]
    public class NodeNavigationController : UmbracoAuthorizedApiController
    {           
        [System.Web.Http.HttpGet]
        public int GetContentNodeByType(string contentType = "", int idCurrentNode = -1)
        {
            contentType = (contentType == "") ? System.Web.HttpContext.Current.Request.QueryString["contentType"] : contentType;
            idCurrentNode = (idCurrentNode == -1) ? Convert.ToInt32(System.Web.HttpContext.Current.Request.QueryString["idCurrentNode"]) : idCurrentNode;

            //var IStartNode = getKundeStartknoten(Convert.ToInt32(idCurrentNode));
            //var startNode = Umbraco.Content(IStartNode.Id);            

            IPublishedContent webpageNode = Helpers.Structure.GetHP4MeWebpageNode(Umbraco.Content(idCurrentNode));
            //UmbracoContext.Current.ContentCache.GetById
            var node = webpageNode.DescendantOfType(contentType);

            return node.Id;
        }

        [System.Web.Http.HttpGet]
        public IPublishedContent GetNewsletterAdminNode(int idCurrentNode)
        {                
            IPublishedContent nlNode = Helpers.Structure.GetHP4MeNewsletterNode(Umbraco.Content(idCurrentNode));
            return nlNode;
            //return Json(nlNode, JsonRequestBehavior.AllowGet);     
        }
    }
}

I already tried to change the return value to JSONResult. But then. I get an error in the line:

return Json(nlNode, JsonRequestBehavior.AllowGet);

AllowGet could not be cast to some Newtonsoft.Json Property.

Any idea what's going an here?

Umbraco version is the newest one.

The error when I call the Controller is:

    <Error>
<Message>An error has occurred.</Message>
<ExceptionMessage>The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'.</ExceptionMessage>
<ExceptionType>System.InvalidOperationException</ExceptionType>
<StackTrace/>
<InnerException>
<Message>An error has occurred.</Message>
<ExceptionMessage>Type 'Umbraco.Web.PublishedModels.NewsletterAdministration' cannot be serialized. Consider marking it with the DataContractAttribute attribute, and marking all of its members you want serialized with the DataMemberAttribute attribute. If the type is a collection, consider marking it with the CollectionDataContractAttribute. See the Microsoft .NET Framework documentation for other supported types.</ExceptionMessage>
<ExceptionType>System.Runtime.Serialization.InvalidDataContractException</ExceptionType>
<StackTrace> at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.ThrowInvalidDataContractException(String message, Type type) at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.CreateDataContract(Int32 id, RuntimeTypeHandle typeHandle, Type type) at System.Runtime.Serialization.DataContract.DataContractCriticalHelper.GetDataContractSkipValidation(Int32 id, RuntimeTypeHandle typeHandle, Type type) at System.Runtime.Serialization.DataContractSerializer.GetDataContract(DataContract declaredTypeContract, Type declaredType, Type objectType) at System.Runtime.Serialization.DataContractSerializer.InternalWriteObjectContent(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver) at System.Runtime.Serialization.DataContractSerializer.InternalWriteObject(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver) at System.Runtime.Serialization.XmlObjectSerializer.WriteObjectHandleExceptions(XmlWriterDelegator writer, Object graph, DataContractResolver dataContractResolver) at System.Runtime.Serialization.DataContractSerializer.WriteObject(XmlWriter writer, Object graph) at System.Net.Http.Formatting.XmlMediaTypeFormatter.WriteToStream(Type type, Object value, Stream writeStream, HttpContent content) at System.Net.Http.Formatting.XmlMediaTypeFormatter.WriteToStreamAsync(Type type, Object value, Stream writeStream, HttpContent content, TransportContext transportContext, CancellationToken cancellationToken) --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Web.Http.WebHost.HttpControllerHandler.<WriteBufferedResponseContentAsync>d__22.MoveNext()</StackTrace>
</InnerException>
</Error>