Creating WCF Data Service operation with in-memory objects - wcf

Question

I am trying to create a WCF DataService using in-memory object graph. This means that the backend is not an Entity Framework store, but a bunch of objects that reside in memory.
I am trying to create a service operation called GetUsersByName that has a single parameter for name and returns the matching users as an IQueryable collection.
I followed the documentation and added the access rules for this operation
config.SetServiceOperationAccessRule("GetUsersByName", ServiceOperationRights.All);
But when the SetServiceOperationAccessRule method is called I receive an exception on the client:
System.AggregateException was unhandled.
Here is the full code for my console application
using System;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.ServiceModel.Description;
using System.Data.Services;
using System.Data.Services.Common;
using System.Collections.Generic;
using System.Runtime.Serialization;
using System.Collections.ObjectModel;
using System.Linq;
using System.Web;
using System.Net.Http;
using System.Net;
using System.IO;
namespace WCF_OData
{
class Program
{
static void Main(string[] args)
{
string serviceAddress = "http://localhost:8080";
Uri[] uriArray = { new Uri(serviceAddress) };
Type serviceType = typeof(UserDataService);
using (var host = new DataServiceHost(serviceType, uriArray)) {
host.Open();
var client = new HttpClient() { BaseAddress = new Uri(serviceAddress) };
Console.WriteLine("Client received: {0}", client.GetStringAsync("Users?$format=json").Result);
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://localhost:8080");
request.Method = "GET";
request.Accept = #"application/json";
using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
{
Console.WriteLine(response.StatusCode);
Console.WriteLine(response.ContentType);
Console.WriteLine((new StreamReader(response.GetResponseStream())).ReadToEnd());
}
Console.WriteLine("Press any key to stop service");
Console.ReadKey();
}
}
}
[EnableJsonSupport]
[ServiceBehavior(IncludeExceptionDetailInFaults = true)]
public class UserDataService : DataService<UserService> {
public static void InitializeService(DataServiceConfiguration config)
{
config.SetEntitySetAccessRule("Users", EntitySetRights.All);
config.SetServiceOperationAccessRule("GetUsersByName", ServiceOperationRights.All);
config.UseVerboseErrors = true;
config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2;
}
}
public class UserService
{
private List<User> _List = new List<User>();
public UserService()
{
_List.Add(new User() { ID = 1, UserName = "John Doe" });
_List.Add(new User() { ID = 2, UserName = "Jane Doe" });
}
public IQueryable<User> Users
{
get
{
HttpContext x = HttpContext.Current;
return _List.AsQueryable<User>();
}
}
[OperationContract]
[WebGet(UriTemplate="GetUsersByName")]
public IQueryable<User> GetUsersByName(string name)
{
return new List<User>().AsQueryable();
}
}
[DataServiceKey("ID")]
public class User
{
public int ID { get; set; }
public string UserName { get; set; }
}
}

Answer 1

It looks like there are a few things going on here, so this may take a couple of iterations to work through. The first problem that should be fixed is the service operation. Service operations need to be declared on the class that inherits from DataService: "Service operations are methods added to the data service class that derives from DataService". Here's a sample:
using System.Data.Entity;
using System.Data.Services;
using System.Data.Services.Common;
using System.Linq;
using System.ServiceModel;
using System.ServiceModel.Web;
namespace Scratch.Web
{
[ServiceBehavior(IncludeExceptionDetailInFaults = true)]
public class ScratchService : DataService<ScratchEntityFrameworkContext>
{
static ScratchService()
{
Database.SetInitializer(new ScratchEntityFrameworkContextInitializer());
}
public static void InitializeService(DataServiceConfiguration config)
{
config.SetEntitySetAccessRule("*", EntitySetRights.All);
config.SetServiceOperationAccessRule("*", ServiceOperationRights.AllRead);
config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V3;
config.UseVerboseErrors = true;
}
[WebGet]
public IQueryable<Product> FuzzySearch(string idStartsWith)
{
var context = new ScratchEntityFrameworkContext();
return context.Products.ToList().Where(p => p.ID.ToString().StartsWith(idStartsWith)).AsQueryable();
}
}
}
You should then be able to call your service operation from a browser, with a URL format similar to the following: http://localhost:59803/ScratchService.svc/FuzzySearch()?idStartsWith='1'
Can we start by trying to get this functional in a browser and then see whether the AggregateException still happens?