formula_in_slack.js

function doPost(e){
	console.log(e.parameter.trigger_word);
	var slackApp = SlackApp.create(slackAccessToken);
	if(e.parameter.trigger_word=="formula:"){
		var chId=e.parameter.channel_id;
		var query = e.parameter.text.substr(e.parameter.trigger_word.length).trim();
		var url="https://chart.googleapis.com/chart?cht=tx&chl="+encodeURIComponent(query.replace(/&amp;/g,'&').replace(/&lt;/g,'<').replace(/&gt;/g,'>'))+"&ts="+String(Date.now());
		slackApp.postMessage(chId, url, {'username':'formula','icon_url':"http://icons.iconarchive.com/icons/alecive/flatwoken/512/Apps-Libreoffice-Math-B-icon.png"});
	}
}