I am faced with a situation where I need to persist an array of properties via AJAX calls to a database. However, the current API does not allow sending the strings in batches, and simple looping will cause overwriting issues. To overcome this, I have implemented a FIFO queue system for processing additions and subtractions.
What I would like to confirm is whether my understanding is correct regarding the interruption of processing actions that add or subtract properties from the queue when an AJAX call back occurs.
Here is the code snippet I am using (using jQuery $.ajax for convenience):
var queue = [],
processing = false;
function processQueue() {
if(queue.length <= 0) {
processing = false;
return;
}
if(processing) {
return;
}
processing = true;
var cmd = queue.unshift();
$.post(cmd.location, cmd.payload, function handleSuccess() {
processing = false;
processQueue();
});
}
function addToQueue(url, payload) {
queue.push({ location: url, payload: payload });
processQueue();
}
My main concern is determining which processQueue(); call will be executed first after the initial one. Let's say I have added several items to the queue and then invoked processQueue();. Based on my understanding, if a call to handleSuccess(); happens during the execution of addToQueue(), the subsequent call to processQueue() within addToQueue() would result in an early return due to processing == true. However, I want to be sure about this.
Can someone verify if my thinking is correct?