George Durzi

Contact Name Resolution using the Office Communicator SDK

In my continuing efforts to bring you useful nuggets from the Office Communicator SDK, I bring you IMessengerContactResolution.

I realized that I needed something like this when I wasn't able to resolve contacts given their SMTP address by using the IMessenger::GetContact method. The IMessenger::FindContact methods wasn't helpful because it actually invoked the Communicator's UI to find a contact.

I came across IMessengerContactResolution::ResolveName in the SDK, but saw that the ResolveName method was marked as Not Implemented. Well, it is ... I didn't find out until someone on the UC team sent me a code snippet that used it. Moral of the story: give it a shot even if the SDK says it's not implemented.

Scenario

The scenario I was working with is that a user could drag a contact out of Communicator into my application. What you get in the drag arguments happens to be the contact's primary SMTP address, which may or may not match their Sip Uri, e.g. john.doe@contoso.com vs. jdoe@contoso.com. A lot of organizations do this, and there's really no standard way to "discover" a user's Sip given their SMTP and vice versa.

My ResolveContact method tries to resolve its input string a couple of different ways. As usual, when programming against the Office Communicator SDK, you unfortunately have to control logic flow using try/catch statements. I feel dirty every time I do that, but hey, my hands are tied :)

ResolveContact

In my application, I carry around a class-level variable called _resolver to perform contact resolution:

private IMessengerContactResolution _resolver;

When I handle the Communicator sign-in event, I set up _resolver by casting my main communicator object to IMessengerContactResolution:

_resolver = _communicator as IMessengerContactResolution;

This is pretty common when writing applications that use the Office Communicator SDK, you of course are responsible for cleaning up those objects which I do when I handle the Communicator sign-out event.

Here's the code for my ResolveContact method:

void ResolveContact(string dropString, out string sipUri, out string displayName)
        {
            try
            {
                sipUri = null;
                displayName = null;

                try
                {
                    // Scenario 1: User enters a Sip Uri
                    //  If so, GetContactDetails will return a display name
                    //
		    // Code for this method not included, 
		    //  It simply called IMessenger::GetContact
                    GetContactDetails(dropString, out displayName);
                }
                catch
                {
                    sipUri = null;
                }

                if (String.IsNullOrEmpty(displayName)) // Not a match based on Sip Uri
                {
                    try
                    {
                        // Scenario 2: User enters an SMTP address
                        //  Try to resolve the SMTP address into a Sip Uri
                        //
                        sipUri = _resolver.ResolveContact(ADDRESS_TYPE.ADDRESS_TYPE_SMTP,
                            CONTACT_RESOLUTION_TYPE.CONTACT_RESOLUTION_CACHED_ONLY, 
		            dropString);
                    }
                    catch
                    {
                        sipUri = null;
                    }

		    // Not a match based on SMTP Address
                    if (String.IsNullOrEmpty(sipUri))
                    {
                        try
                        {
                            // Scenario 3: User enters a contact's display name
                            //  Try to resolve the Display Name into a Sip Uri
                            //
                            sipUri = _resolver.ResolveContact(
				ADDRESS_TYPE.ADDRESS_TYPE_DISPLAY_NAME,
                                CONTACT_RESOLUTION_TYPE.CONTACT_RESOLUTION_CACHED_ONLY, 
				dropString);
                        }
                        catch
                        {
                            sipUri = null;
                        }
                    }

	            // Success - get the contact's Display Name
                    if (!String.IsNullOrEmpty(sipUri)) 
                    {
                        GetContactDetails(sipUri, out displayName);
                    }
                }
                else
                {
                    sipUri = dropString; // Scenario 1
                }
            }
            catch (Exception exception)
            {
                throw exception;
            }
        }