Ordered processing of CF.request() results for CommandFusion iViewer

OrderedRequestQueue.js

/* OrderedRequestQueue.js
 *
 * Push CF.request calls using this object instead of directly using CF.request, and
 * you'll be guaranteed to receive results in the order you pushed them. Note that this
 * implies that the queue will BLOCK until each result is received in sequence, which may
 * cause large delays if one site in the list is long to respond.
 *
 * Use at your own risk
 */
var OrderedRequestQueue = (function(){
	var self = {
		q: [],
		nextDequeue: 0,
		nextEnqueue: 0
	};

	self.addRequest = function(url, method, headers, body, callbackFunction) {
		var reqid = self.nextEnqueue++;
		self.q[reqid] = { callback: callbackFunction };
		CF.request(url, method, headers, body, function(status, resHeader, resBody) {
			self.q[reqid].result = [status, resHeader, resBody];
			processResultQueue();
		});
	};

	function processResultQueue() {
		while (self.nextDequeue < self.nextEnqueue) {
			var entry = self.q[self.nextDequeue];
			if (entry !== undefined) {	// has been manually removed from queue?
				if (entry.result === undefined) {
					break;					// result not yet received, block queue processing
				}
				if (entry.callback != null) {
					try {
						entry.callback.apply(null, entry.result);
					} catch (e) {
						CF.log("Exception catched while calling CF.request callback: " + e);
					}
				}
				delete self.q[self.nextDequeue];
			}
			self.nextDequeue++;
		}
	}

	return self;
})();

/* Example use:
 *
 * OrderedRequestQueue.addRequest(url,"GET",{},"body",function(status, headers, body) {
		CF.log("Got result " + body + " (status " + status + ")");
	});
 */