Send IEnumerable from web api controller to angular js - angularjs

Question

I'm trying to send a IEnumerable from a web api controller to a AngularJs controller.
The code I was using was
Web Api:
readonly InventoryEntities _db = new InventoryEntities();
public IEnumerable<FDVOEligibilityRequest> Get()
{
return _db.FDVOEligibilityRequests.AsEnumerable();
}
AngularJS:
//get all customer information
$http.get("/api/Customer/").success(function (data) {
$scope.requests = data;
$scope.loading = false;
})
.error(function () {
$scope.error = "An Error has occured while loading posts!";
$scope.loading = false;
});
This worked fine, but now I'm using linq to include related tables and it doesn't work. The angularJs code is the same.
What am I doing wrong?
readonly InventoryEntities _db = new InventoryEntities();
public IEnumerable<FDVOEligibilityRequest> Get()
{
return _db.FDVOEligibilityRequests
.Include("FDVOEligibilityRequestMandatoryField")
.Include("FDVOEligibilityRequestDCCField").AsEnumerable();
}
I do get the data I want in the controller, but when i try to send it back to angular, I get a 500 (Internal Server Error) angular.js:10722
This is what FDVOEligibilityRequest looks like in the new Web Api controller
public partial class FDVOEligibilityRequest
{
public int Id { get; set; }
public string TestName { get; set; }
public string GroupName { get; set; }
public int MandatoryFieldsID { get; set; }
public int DCCFieldsID { get; set; }
public virtual FDVOEligibilityRequestMandatoryField FDVOEligibilityRequestMandatoryField { get; set; }
public virtual FDVOEligibilityRequestDCCField FDVOEligibilityRequestDCCField { get; set; }
}

Answer 1

If it's 500 and happens after you successfully make a return from your action then it can be an exception during serialization.
I would suggest to check that there are no circular references between FDVOEligibilityRequest and FDVOEligibilityRequestMandatoryField/FDVOEligibilityRequestDCCField.
Or try to diagnose it using code from here:
string Serialize<T>(MediaTypeFormatter formatter, T value)
{
// Create a dummy HTTP Content.
Stream stream = new MemoryStream();
var content = new StreamContent(stream);
/// Serialize the object.
formatter.WriteToStreamAsync(typeof(T), value, stream, content, null).Wait();
// Read the serialized string.
stream.Position = 0;
return content.ReadAsStringAsync().Result;
}
try {
var val = _db.FDVOEligibilityRequests
.Include("FDVOEligibilityRequestMandatoryField")
.Include("FDVOEligibilityRequestDCCField").AsEnumerable();
var str = Serialize(new JsonMediaTypeFormatter(), val);
}
catch (Exception x)
{ // break point here
}
ps: the common suggestion in this case is to use DTOs instead of EF objects with something like Automapper.