Question

I’m trying to setup a session in Active Record for each WCF request. Here is the code:

[WebGet(UriTemplate = "ReadMessages?authUserId={authUserId}&authGuid={authGuid}&userId={userId}&lastMessageId={lastMessageId}&startDate={startDate}&endDate={endDate}")]
        public IQueryable<Message> ReadMessages(int authUserId, string authGuid, uint userId, uint lastMessageId, 
            DateTime startDate, DateTime endDate)
        {
            UserUtility.Authenticate(authUserId, authGuid);

            using (new SessionScope())
            {
                //get messages.
                return from m in MessageData.FindAll(userId, lastMessageId, startDate, endDate)
                    select ConvertToView(m);
            }
        }

Even though I have the SessionScope using block, it still gives me a lazy load error because it’s returning an IQueryable and so it’s converting to a view, which triggers lazy loading, after it’s out of the using block I’m guessing. Here is the error:

Initializing[xxx.Business.Schemas.CommonSchemas.Models.Messaging.Message#6575]-failed to lazily initialize a collection of role: xxx.Business.Schemas.CommonSchemas.Models.Messaging.Message.MessageStatusHistories, no session or session was closed

In my configuration, I have IsRunningWebApp as true.

var source = new InPlaceConfigurationSource();
source.IsRunningInWebApp = true;

If you’re wondering why I’m returning IQueryable from a WCF web method, it’s because I’m using the WCF Web API (http://wcf.codeplex.com/wikipage?title=WCF%20HTTP), which allows you to query your objects in the url querystring using ODATA.

What am I doing wrong? How do I create a session that lives long enough to lazy load the models as I convert them to views on return from the web methods?

Answer 1

I ended up getting it working using this in my Global.asax:

public void Application_BeginRequest(object sender, EventArgs e)
        {
            HttpContext.Current.Items.Add("ar.sessionscope", new SessionScope());
        }

        public void Application_EndRequest(object sender, EventArgs e)
        {
            try
            {
                var scope = HttpContext.Current.Items["ar.sessionscope"] as SessionScope;
                if (scope != null)
                    scope.Dispose();
            }
            catch (Exception ex)
            {
                HttpContext.Current.Trace.Warn("Error", "EndRequest: " + ex.Message, ex);
            }
        }

Note: I also had to remove the using(new SessionScope()) from the web method, that will interfere with the solution above.