Gus What?!

With so many different AIM clients out there, how can we tell if a client supports a particular feature? The answer is capabilities. Each screen name has a list of capabilities (GUIDs) that are asserted by the client and plugins.

How can I read these capabilities in the AIM SDK, you might ask? You can see what a user supports via the AccUserProp_Capabilities property and what the client asserts via the AccSessionProp_Capabilities property.

Here is a dump of the capabilities property for one of my screen names as seen by my CoreWitness plugin:

  AccUserProp_Capabilities = Array { ...GUIDs removed from trace here... } 
      {09461345-4C7F-11D1-8222-444553540000} = Direct IM
      {748F2420-6287-11D1-8222-444553540000} = Chat
      {09461343-4C7F-11D1-8222-444553540000} = File Transfer
      {67753137-6A38-6C77-4672-762D49755071} = UUID of a plugin: 'Gus Verdun's Core Test Plug-in (Dev)'
      {09461346-4C7F-11D1-8222-444553540000} = Buddy Icon
      {9FD3969B-84CB-45C1-B5DF-72DF5FAAB98E} = RX-Plugin

The AIM SDK returns an array of GUIDs in string form for those two properties. The CoreWitness plugin will automatically map the GUIDs to friendly names. When it encounters a GUID it does not recognize, it scans to see if the GUID matches that of any plugin you have installed. Yes, you can assert your plugin’s key as a capability if you want too. However, this is not required even thought your plugin’s key is reserved for you. I chose long ago to assert a different GUID as a capability for my RX-Plugin as you can see above. The capability is used to change the behavior of the IMpulse feature when both users have the RX-Plugin installed.

The AIM SDK always returns VB arrays in JavaScript so you must convert them to a JS array by using the toArray() method. Here is one way you can test to see if a buddy supports a particular capability:

// Test to see if buddy (IAccUser) has the RX-Plugin capability asserted
function HasRXPlugin(buddy)
{
    if ( SafeHasCapability(buddy, '{9FD3969B-84CB-45C1-B5DF-72DF5FAAB98E}') )
        alert('yes');
    else
        alert('no');
}
 
// cap must be in upper case.
function SafeHasCapability(user, cap)
{
    try {
        return  user.capabilities.toArray().join('').indexOf(cap) >= 0;
    } catch ( e ) {
        return false;
    }
}

The first function calls the more general function to test if the buddy has the capability asserted by my RX-Plugin.

You can use capabilities in your plugins for anything. They can be used to indicate that something is “on”, “selected”, etc. You can even have more than one—within reason. The AIM Vote ‘08 plugin uses capabilities to indicate your vote for McCain or Obama and then tallies up the number of buddies with either of those capabilities.

Here is the JavaScript edition of my previous post:

function SafePushTestFeed(session)
{
    try {
        manager = session.buddyFeedManager;
        myitem = manager.createBuddyFeed();
        myitem.feedTitle = 'Feed Title';
        myitem.feedLink = 'Feed Link';
        myitem.feedDescription = 'Feed Description'; 
        myitem.feedPublisher = 'Feed Publisher'; 
        myitem.itemTitle = 'Item Title';
        myitem.itemLink = 'Item Link';
        myitem.itemDescription = 'Item Description'; 
        myitem.itemGuid = 'Item Guid';
        myitem.itemCategory = 'Item Category';
        manager.push(myitem);
    }
    catch ( e ) 
    {
        // You can look this number up in the 
        // CoreWitness Symbol Lookup Dialog
        trace("Exception HRESULT=" + e.number);
    }
}

The buddyFeedManager is a property of the IAccSession interface. In C++ you access properties via the get_Property(prop, value) or get_XXX methods. However, from JavaScript you can access any property including the AccXXXProp_ ones by just using the property’s trailing name (everything after the AccXXXProp_ or get_). Property and method names are not case sensitive in JavaScript.

You can read more about the these interfaces by searching for the interface reference pages on IAccBuddyFeed and IAccBuddyFeedManager.