Question

I have a service that attempting to serialize a list into JSON (using JSON.NET) and return as a string. That’s all well and good, but my JSON is coming back wrapped and I can’t figure out why.

<string xmlns="http://schemas.microsoft.com/2003/10/Serialization/">[{"DoNotSolicitID":5,"FirstName":"test","LastName":"mcTest","Address1":"11 Elm St","Address2":null,"City":"testville","State":null,"Zip":null,"Zip4":null,"Email":"[e-mail]","Phone":null,"BusinessName":null,"PartnerID":"3","Origination":"RDI"},{"DoNotSolicitID":6,"FirstName":"test","LastName":"mcTest","Address1":"11 Elm St","Address2":null,"City":"testville","State":null,"Zip":null,"Zip4":null,"Email":"[e-mail]","Phone":null,"BusinessName":null,"PartnerID":"3","Origination":"RDI"}]</string>

The code making the call is:

return JsonConvert.SerializeObject(Lookup(guid, criteria), Formatting.None);

private IList<DNSContract> Lookup(string guid, SearchCriteria criteria)
    {
        apiAuthentication = new APIKeyAuthentication();
        if (!apiAuthentication.IsValidAPIKey(guid))
            throw new WebFaultException<string>("Invalid Key", HttpStatusCode.Forbidden);

        var searchObj = ToSearchObject(criteria);

        SetContext();

        return Svc.SelectWithCriteria(searchObj).Data;
    }

UPDATE: This is a WCF service and in the browser, and fiddler I get the same XML tags. Also, making the call from jQuery/ajax blows up, presumably because it’s getting the tags as well, not the JSON.

UPDATE 2: the SetContext() call will set the ContentType based on the desired type. In this case I’m simply doing the following for JSON in the base class for the REST services:

 OutgoingWebResponseContext response = WebOperationContext.Current.OutgoingResponse;
 response.ContentType = "application/json";
 response.StatusCode = HttpStatusCode.OK;

So I’m setting the ContentType in teh rsponse and returning a string as a simple output in the service method. This is the interface I’m implementing:

[OperationContract]
    [WebGet(UriTemplate = "/{guid}/search/json?fname={firstname}&lname={lastname}&phone={phone}&email={email}&add1={address1}&add2={address2}&city={city}&state={state}&zip5={zip5}")]
    string LookupRecord(string guid, string firstname, string lastname, string phone, string email, string address1, string address2, string city, string state, string zip5);

Perhaps something in the WebGet that I need to explicitly format to be JSON?

Answer 1

My problem was that I was not setting the context’s OutgoingResponse.Format to JSON. The context code for a valid JSON response in my situation is

context.ContentType = "application/json";
context.StatusCode = HttpStatusCode.OK;
context.Format = WebMessageFormat.Json;

Oddly enough, setting the attributes on the web method didn’t do anything, I had to set the context explicitly. Since I need to handle XML and JSON responses, this seems the best approach I’ve found.