Some Tips for Writing JavaScript Adapters for IBM MobileFirst

i’ve been doing a lot of playing lately with mobilefirst , and one of the cooler features it has is the ability to write adapters in javascript. i blogged about this last week and today i thought i’d share a few tips/notes for folks who may be new to this feature.

first and foremost, it is important to remember that you are not using a full node.js-style stack. you are working with a subset of the rhino container developed by mozilla. this is a javascript engine that runs within the context of a java server. however, this is not a full rhino implementation as some features, like load(), are not implemented. unfortunately we don’t document these differences (yet – i’m filing an enhancement request for this today).

second, you cannot debug via console.log. instead, simply use the wl.logger api as shown below:

function getdetail(id) {
	wl.logger.info("getdetail, requesting id "+id);
	return wl.server.invokesqlstatement({
		preparedstatement : getdetailstmt,
		parameters:[id]
	});
}

and where do those logs show up? type mfp logs at the command line to be shown where your logs exist:

then you can simply go to that directory and look at messages.log. i’d simply tail -f it while you work to see incoming messages. the log is a bit verbose, but you could use other tools to filter it out.

the third point to consider is that adapters are session-based. that means you can persist data by simply using a global javascript variable, but it will not be global to the server.

finally, and i’ve mentioned these before, but don’t forget that you need to “build/deploy” when you edit your adapter files. you can use the bd shortcut for adapters just like you do for your web assets: mfp bd . you can also test your adapters directly from the command line using mfp invoke .