observe devices inside rack chain

ive just tested this in ableton live 9 and found that this works as expected. Something must have changed between live 8 and 9 that has resulted in this functionality now working. Is there anyone that can confirm this?

The code basically bangs when something is added or deleted in a rack chain, or track.

Also, would be really grateful to find out if there is a way of doing this in js. ie to observe all levels of chains, rather than the 1st level.

newtfish, I posted a JS in answer to your last post about iterating devices in chains which demonstrates how to find all of the devices. You should be able to install observers along the way and get what you want.

Best, Jeremy

cool thx for this jeremy, your js solution is amazing! :)

Im not that great with js, so i try the following code, with callbacks, but I dont get any output when observed (device is deleted or added). Is there something im doing drastically wrong? grateful for any help.

autowatch = 1;
outlets = 4;
function bang()
{
    var api = getTrackPath();
    if (!api) return;

    iterateDevices(api);
}

function iterateDevices(api)
{
    var count = api.getcount("devices");
    var apiPath = dequotePath(api);
    for (var i = 0; i < count; i++) {
        var deviceApi = new LiveAPI(callback,apiPath + " devices " + i);
        if (deviceApi) {
            var deviceName = deviceApi.get("name");
            var deviceId = deviceApi.id;
            var deviceApiPath = dequotePath(deviceApi);
            var chainsCount;
            var chainApi;
            var j;

//            post("found device " + deviceName + " at path '" + deviceApiPath + "'n");
            outlet(0, "append", deviceName);
            outlet(1, "append", deviceId);
            if (deviceApi.get("can_have_chains") == 1) {
                chainsCount = deviceApi.getcount("chains"); // only racks have chains
                for (j = 0; j < chainsCount; j++) {
                    chainApi = new LiveAPI(callback,deviceApiPath + " chains " + j);
                    iterateDevices(chainApi);
                }
                chainsCount = deviceApi.getcount("return_chains"); // only racks have chains
                for (j = 0; j < chainsCount; j++) {
                    chainApi = new LiveAPI(callback,deviceApiPath + " return_chains " + j);
                    iterateDevices(chainApi);
                }
            }
        }
    }
}
iterateDevices.local = 1;

function getTrackPath()
{
    var api = new LiveAPI("this_device");
    if (api) {
        trackPath = dequotePath(api);
        trackPath = trackPath.replace(/s+devices.*?$/g, ""); // remove 'devices N' at the end
        return new LiveAPI(trackPath);
    }
    return null;
}
getTrackPath.local = 1;

function dequotePath(api)
{
    return api.path.replace(/"/g, ""); // remove quotes
}
dequotePath.local = 1;
function callback(args)
{
  outlet(0,args[1]);
  outlet(1,this.id);
post(args);
}

Try this. I might have mangled your additions a little, but I think it's right. There may be a couple of things going wrong in your version:

- in addition to the callback function, you need to assign the LiveAPI object's "property" attribute to the property you want to observe. In the case of the track, this is "devices", in the case of a rack device, this is "chains", in the case of a chain, this is "devices" and so on.
- once a JavaScript object goes out of scope it can be garbage collected if it's not in use elsewhere. So I'm stuffing the objects that we're observing into a global array to be certain that they can't disappear.

Note that to observe both chains and return chains, you actually need 2 LiveAPI objects (each object can only observe 1 property). I left this as an exercise to the reader.

Best, Jeremy

Sorry, forgot the JS.

thanks Jeremy,

There seems to be a bit of a problem with the unquotedpath in this script? Im wondering what unquotedpath is? Is this something built into the object? The first error I get is when using unquotedpath, which results in trackPath throwing an undefined error.

Oh sorry, I was testing something here and forgot to change it back. Remove that line and uncomment the one below it.

Best, Jeremy

This is really amazing, didnt realise js was so useful. Thanks so much Jeremy.

The one thing I have noticed is that when a device is added in an existing chain, the device id is output. However, if I drag a device to create a new chain (automatically creating a new chain by dragging), then it only outputs the chains and not the new device id. I also noticed this behaviour when using the max objects, it doesnt seem to notice the new device id. Maybe this is a feature that im missing. Ideally, I would really like to just refresh the individual id that is added/deleted, but this works great for now, so I can just check if something has changed within a rack and refresh all device ids on the track.

Cheers Jeremy :)