For the simple API that I create, I use a couple of methods. First of all, this is not my first API that I create, but this is the first where I have a combination of WCF, json and anonymous objects.
I got the following interface for the WCF API:
[ServiceContract] public interface IAPI { [OperationContract] [WebInvoke(Method = "POST", BodyStyle = WebMessageBodyStyle.WrappedRequest, ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)] ServiceResponse Authenticate(string username, string hashedPassword); [OperationContract] [WebInvoke(Method = "POST", BodyStyle = WebMessageBodyStyle.WrappedRequest, ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)] ServiceResponse GetProducts(); }
All this is quite simple, only 2 methods that I want to have. The ServiceResponse class that you see there is also very simple, but it causes problems that I think:
[DataContract] public class ServiceResponse { [DataMember] public ResponseCode Status { get; set; } [DataMember] public object Value { get; set; } }
I created this class, so I can always send Status (Simple int enum) and an object, such as a string or a list of objects.
I created a small script using jQuery to test my service, and the Authenticate method works as it should, but this method returns a ServiceResponse object, just 0 in the Status field. The Value field is empty here.
The GetProducts method is the one where it gets complicated, an array of anonymous objects, for example:
public ServiceResponse GetProducts() { DataClassesDataContext db = new DataClassesDataContext(); var results = from p in db.Products where p.UserID == 1 select new { ID = p.ID, Name = p.DecryptedName }; return ServiceResponse.OK(results.ToArray()); }
I use an anonymous type object here because I don't want to create proxy classes for all the classes that I want to use in the API.
When I try this code, with my simple jQuery script, FireBug tells me that my request was aborted. I think this is due to a 500 error or something like that. When I set a breakpoint in my GetProducts method, it hits 7 times before Firefox says that it is interrupted and the script is fully running.
Here is an example jQuery script that I use to test my WCF service:
$.ajax({ type: "POST", contentType: "application/json; charset=utf-8", url: "/Handlers/API.svc/GetProducts", data: '{}', dataType: "json", success: function (response) { var test = inspect(response, 5); $("#output").html(test); }, error: function (message) { $("#output").html(inspect(message, 5)); } });
The inspect method that you see there is a small JS script that shows me the contents of an object.
I tried to do the following:
- Replace anonymous objects with objects of type
Product , but this did not succeed in the same way. - Return a
List<T> instead of an array, but no luck there either. - Returning without binding to the
Value property, it worked - By changing the
Value property to dynamic , this also failed
I would really like it if I could use WCF to return some array of anonymous objects, because it allows me to create 30+ proxy classes.
NOTE The Product class is the class generated by LINQ. I use C # 4.0 for this.