Captivate SCORM 2004 Output, preventing redundant GetLastError calls

scorm_support.js

/*global CaptivateSWF */

var SCORM_API = null,
	unloaded = false,
	isInitialized = false,
	isTerminated = false,
	courseStatus,
	value_store = [],
	lastCommand,
	setValueWasSuccessful = true;


/*
   cmiCache(property, value)
   Caches CMI value to help prevent sending duplicate data to LMS

   Parameters: property (CMI property name), value (CMI value, normally a string)
   Returns:    property value if cached version found, false if not cached.
*/

var cmiCache = function(property, value){

	//Ensure we have a valid property to work with
	if(typeof property === "undefined"){ return false; }

	//Replace all periods in CMI property names so we don't run into JS errors
	property = property.replace(/\./g,'_');

	//If cached value exists, return it
	if(typeof value_store[property] !== "undefined"){
		return value_store[property];
	}

	//Otherwise add to cache
	if(typeof value !== "undefined"){
		value_store[property] = value;
	}

	return false;

};


/*
   findAPI(window)
   Adapted from pipwerks SCORM wrapper
   https://github.com/pipwerks/scorm-api-wrapper

   Looks for an object named API in parent and opener windows

   Parameters: window (the browser window object).
   Returns:    Object if API is found, null if no API found
*/

var findAPI = function(win){

    var API,
        findAttempts = 0,
        findAttemptLimit = 500;

    while (!win.API_1484_11 && win.parent && win.parent != win && findAttempts <= findAttemptLimit){
        findAttempts++;
        win = win.parent;
    }

	API = win.API_1484_11 || null;

    /*
	if(!API){
        alert("Error finding API. \nFind attempts: " +findAttempts +". \nFind attempt limit: " +findAttemptLimit);
    }
	*/

    return API;

};


/*
   getAPI()
   Adapted from pipwerks SCORM wrapper
   https://github.com/pipwerks/scorm-api-wrapper

   Looks for an object named API_1484_11, first in the current window's frame
   hierarchy and then, if necessary, in the current window's opener window
   hierarchy (if there is an opener window).

   Parameters:  None.
   Returns:     Object if API found, null if no API found
*/

var getAPI = function(){

    var API = null,
        win = window;

	//Look in parent windows first
    if(win.parent && win.parent != win){
        API = findAPI(win.parent);
    }

	//Look in opener windows next
    if(!API && win.top.opener){
        API = findAPI(win.top.opener);
    }

    //Plateau LMS needs special hand-holding
    if(!API && win.top.opener && win.top.opener.document) {
        API = findAPI(win.top.opener.document);
    }

    //if(!API){ alert("getAPI failed: Can't find the API!"); }

    return API;

};


var Captivate_DoExternalInterface = function (command, parameter, value, variable) {

	console.log("Captivate_DoExternalInterface: " +command +", " +parameter +", " +value);

	var strErr = "true",
		intercept = false;

	//Ensure SCORM API was initialized
	if(!isInitialized){ return; }

	if(command === "Initialize"){

		//We already initialized, just nod politely
		//and tell the SWF everything is okay!

	} else if(command === "SetValue"){

		if(parameter === "completion_status"){ courseStatus = value; }

		//Check to see if value is already cached
		var cached_value = cmiCache(parameter, value);

		//Only send value to LMS if it hasn't already been sent;
		//If value is cached and matches what is about to be sent
		//to the LMS, prevent value from being sent a second time.
		if(!cached_value || cached_value !== value){
			console.log(parameter +"(" +value +") is not cached. Sending to LMS.");
			strErr = SCORM_API.SetValue(parameter, value);
			setValueWasSuccessful = (strErr === "true");
		} else {
			console.log(parameter +"(" +value +") has already been sent. Preventing redundant LMS communication.");
			//Fakin' it for Captivate's sake.
			setValueWasSuccessful = true;
		}

	} else if(command === "Terminate"){

		strErr = SCORM_API.Terminate("");
		isTerminated = (strErr === "true");

	} else if(command === "Commit"){

		strErr = SCORM_API.Commit("");

	} else if(command === "GetLastError"){

		if(lastCommand === "SetValue" && setValueWasSuccessful){
			strErr = "";
			console.log("Last Get/Set was successful. Preventing pointless GetLastError invocation.");
		} else {
			strErr = SCORM_API.GetLastError();
		}

	} else if(value && value.length > 0){

		strErr = SCORM_API[command](parameter);

	}

	CaptivateSWF.SetScormVariable(variable, strErr);

	lastCommand = command;

	return strErr;

};


var initializeSCORM = function (){

	isInitialized = SCORM_API.Initialize("");

	if(isInitialized){

		console.log("SCORM initialized. Ready to go!");
		courseStatus = SCORM_API.GetValue("cmi.completion_status");

		if(courseStatus === "not attempted"){
			SCORM_API.SetValue("cmi.completion_status", "incomplete");
		}

	}

};

var unloadHandler = function (){
	if(!unloaded && isInitialized && !isTerminated){
		var exit_status = (courseStatus === "incomplete") ? "suspend" : "normal";
		SCORM_API.SetValue("cmi.exit", exit_status); //Set exit to whatever is needed
		SCORM_API.Commit(""); //Ensure that LMS saves all data
		isTerminated = (SCORM_API.Terminate("") === "true"); //close the SCORM API connection properly
		unloaded = true; //Ensure we don't invoke unloadHandler more than once.
	}
};

window.onbeforeunload = unloadHandler;
window.onunload = unloadHandler;

//Initialize SCORM API
SCORM_API = getAPI();