private async Task ExecuteChangeSet(
ChangeSetRequestItem changeSet,
IList<ODataBatchResponseItem> responses,
CancellationToken cancellation)
{
ChangeSetResponseItem changeSetResponse;
// Create a new ShoppingContext instance, associate it with each of the requests, start a new
// transaction, execute the changeset and then commit or rollback the transaction depending on
// whether the responses were all successful or not.
using (ShoppingContext context = new ShoppingContext())
{
foreach (HttpRequestMessage request in changeSet.Requests)
{
request.SetContext(context);
}
using (DbContextTransaction transaction = context.Database.BeginTransaction())
{
changeSetResponse = (ChangeSetResponseItem)await changeSet.SendRequestAsync(Invoker, cancellation);
responses.Add(changeSetResponse);
if (changeSetResponse.Responses.All(r => r.IsSuccessStatusCode))
{
transaction.Commit();
}
else
{
transaction.Rollback();
}
}
}
}
public static void Register(HttpConfiguration config)
{
// Read the model directly from entity framework.
IEdmModel model;
using (ShoppingContext context = new ShoppingContext())
{
model = context.GetEdmModel();
}
// Create our batch handler and associate it with the OData service.
ODataBatchHandler batchHandler = new EntityFrameworkBatchHandler(GlobalConfiguration.DefaultServer);
config.Routes.MapODataServiceRoute("odata", "odata", model, batchHandler);
}
/// <summary>
/// Retrieves a <see cref="ShoppingContext"/> instance associated with the current request. If no instance is
/// associated it will create a new one, associate it with the current request and register it for disposal at
/// the end of the request.
/// </summary>
/// <param name="request">The request from which to retrieve the <see cref="CustomerContext"/> instance.</param>
/// <returns>A <see cref="CustomerContext"/> instance associated with this request.</returns>
public static ShoppingContext GetContext(this HttpRequestMessage request)
{
object customersContext;
if (request.Properties.TryGetValue(DB_Context, out customersContext))
{
return (ShoppingContext)customersContext;
}
else
{
ShoppingContext context = new ShoppingContext();
SetContext(request, context);
request.RegisterForDispose(context);
return context;
}
}
/// <summary>
/// Associates a given instance of a DbContext to the current request.
/// </summary>
/// <param name="request">The request to will the DbContext instance will be associated.</param>
/// <param name="context">The DbContext instance to associate with the request.</param>
public static void SetContext(
this HttpRequestMessage request,
ShoppingContext context)
{
request.Properties[DB_Context] = context;
}