Accessing Tracker.Current.Contact in ApiController

Question

I have a scenario in which I want to return some facet data associated with an xDB contact via an ApiController. However, when i try to access the Tracker.Current.Contact property it is null.

What is the best solution to ensure access to a contact when performing ApiController calls?

Currently my code looks like this:

public class WidgetsController : ApiController {

[HttpGet]
public IEnumerable<Widget> Get()
{
    if (Sitecore.Analytics.Tracker.Current != null) 
    {
        var contact = Sitecore.Analytics.Tracker.Current.Contact;
        if (contact != null)
        {
            return WidgetsRepository.Get(contact);
        }
    }
}

Answer 1

Even though your code is running in an API controller, the browser will still send cookies to the server, including the SC_ANALYTICS_GLOBAL_COOKIE. This cookie contains the current contact's ID in plain text. You can extract the contact ID in your WebAPI controller and get the current contact from the session (if it's there) or from the database. Here's how:

var contactCookie = new Sitecore.Analytics.Web.ContactKeyCookie();

if (!contactCookie.IsNewContact)
{
    Guid contactId = contactCookie.ContactId;

    var contactRepository = (ContactRepositoryBase)Factory.CreateObject("contactRepository", true);
    var sharedSessionManager = (SharedSessionStateManager)Factory.CreateObject("tracking/sharedSessionState/manager", true)

    // Try to load the contact from the Shared Session.
    Contact sessionContact = sharedSessionManager.LockAndLoadContact(contactId);

    if (sessionContact != null)
    {
        try
        {
            // Read facet data from sessionContact
        }
        finally
        {
            sharedSessionManager.SaveAndReleaseContact(sessionContact);
        }
    }
    else
    {
        // The contact is not in an active session on this server.
        // So we'll read it directly from the database:
        Contact databaseContact = contactRepository.LoadContactReadOnly(contactId);

        if (databaseContact != null)
        {
            // Read facet data from databaseContact
        }
        else
        {
            // The contact wasn't found in the Collection database.
            // Handle gracefully.
        }
    }
}
else
{
    // There is no current contact session.
    // Handle gracefully.
}

Note that I am first checking whether or not the contact exists in the Shared Session. If it's not there, I read the contact from the Collection database in a read-only mode.

Answer 2

For writing contact information, the best practice is to not use API calls and do your work in the shared session within the Page Context on the Content Delivery servers.

For reading contact information, in an API, the Best Practice is passing the contact id through the API and loading a read only contact to gain the information you need.

public class WidgetsController : ApiController
{
    [HttpGet]
    public IEnumerable<Widget> Get(Guid contactId)
    {
        var contactRepository =
            (ContactRepositoryBase) Sitecore.Configuration.Factory.CreateObject("contactRepository", true);
        var contact = contactRepository.LoadContactReadOnly(contactId);

        if (contact != null)
        {
            return WidgetsRepository.Get(contact);
        }
    }
}

If you must use an API for writing information to a contact, you will have to use the FlushToXdb() method to save to Mongo directly or use the SharedSessionStateManager. Be advised though, that the contact record in session on the CD won't be affected if you are trying to perform operations on the CM server.

Answer 3

Have a look at this solution. You can make an API call session-aware and then use Tracker.Current.Session.**Contact**

 public class MakeWebApiSessionAware
    {
         public void Process(PipelineArgs args)
        {
            var route = RouteTable.Routes[SetupRoutes.ApiRouteSessionAwareKey] as Route;

            if (route != null)
            {
                route.RouteHandler = new SessionRouteHandler();
            }
        }
    }

    public class SessionRouteHandler : IRouteHandler
    {
        IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext)
        {
            return new SessionControllerHandler(requestContext.RouteData);
        }
    }

    public class SessionControllerHandler : HttpControllerHandler, IRequiresSessionState
    {
        public SessionControllerHandler(RouteData routeData)
            : base(routeData)
        {
        }
    }

Pipelines setup:

<sitecore>
    <pipelines>
      <initialize>        
        <processor patch:after="processor[@type='X.Y.Pipelines.SetupRoutes, X.Y.Business']"
              type="X.Y.Business.Pipelines.MakeWebApiSessionAware" />
       </initialize>
    </pipelines>
  </sitecore>

The idea came from here: http://jockstothecore.com/xdb-tracking-the-untrackable-part-1/

Answer 4

If you don't use a normal controller, then the Context will not be available and thus the tracker wont be available.

To use an API, you would have to pass in the identifier (email address or username) of the user and get the tracker object that way. This will be become an issue because the contact will be on the site, thus the contact record will be locked. You will only be able to read from the object, not write.

public class WidgetsController : Controller {

    [HttpGet]
    public IEnumerable<Widget> GetTrackerInfo()
    {
        if (Sitecore.Analytics.Tracker.Current != null) {
            var contact = Sitecore.Analytics.Tracker.Current.Contact;
            if (contact != null)
            {
                return WidgetsRepository.Get(contact);
            }
        }
    }
}