deferred

I really like the idea of jQuery's deferred/promise pattern or paradigm but sometimes I have trouble wrapping my aging brain around the finer points or specific implementation details. In fact recently I've found that the deferred/promise pattern/paradigm seems to predate jQuery and is also in at least these other JavaScript libraries/frameworks: Deferred github Q homepage task.js homepage when.js github wire.js github , presentation YUI gallery-deferred module I've probably missed some, included stuff that's really part of one of the others, and made other mistakes in that list... Please edit

I have a Django website, and one page has a button (or link) that when clicked will launch a somewhat long running task. Obviously I want to launch this task as a background task and immediately return a result to the user. I want to implement this using a simple approach that will not require me to install and learn a whole new messaging architecture like Celery for example. I do not want to use Celery! I just want to use a simple approach that I can set up and get running over the next half hour or so. Isn't there a simple way to do this in Django without having to add (yet another) 3rd

I'm mostly using programming languages like Scala and JavaScript. I'm trying to understand the similarities and differences in how async reactive programming is used in both languages. Can you help me? I'm not taking any particular Js Promise framework because it seems many implement the similar specifications (like Promise/A). I've only used Q so far. It seems that in Javascript we call a Deferred the object we resolve to complete a Promise . In Scala, it seems the Promise is the object you resolve to get a Future monad. Can someone tell me if this is right? Is there any good reason for a

I have used promises in jQuery slightly before - but I am having trouble applying it to this scenario. I prefer to use the $.when() and $.done() methods to achieve this. From what I understand I need to build a $.Deferred object which logs the requests and when those requests are finished - fire the callback. In my code below the callback is firing before the ajax requests and not after - maybe I just need some sleep I know my code is incomplete I have been struggling to apply it with the addition of the for loop. http://jsfiddle.net/whiteb0x/MBZEu/ var list = ['obj1', 'obj2', 'obj3', 'obj4',

Let's create a simple Deferred object: defer = $.Deferred( function ( defer ) { setTimeout( defer.resolve, 3000 ); }); The above Deferred object will be in the "pending" state for 3 seconds, and then switch to the "resolved" state (at which point all the callbacks bound to it will be invoked). Let's also retrieve the promise of that Deferred object: promise = defer.promise(); Now, to add callbacks which are going to be invoked once the Deferred object is resolved, we can use .done() or .then() . However, we can invoke this method both on the Deferred object itself or its own promise object.

In the following code is it also necessary to close the response body in the error case: res, err := http.Get(url) if err != nil { log.Printf("Error: %s\n", err) } defer res.Body.Close() General concept is that when a function (or method) has multi return values one being an error , error should be checked first and only proceed if the error is nil . Functions should return zero values for other (non-error) values if there is an error . If the function behaves differently, it should be documented. http.Get() does not document such deviation. So it should be handled like this: res, err := http

I've spent far too many hours searching for similar questions and trying solutions, so I hope someone has a solution. Basically, I would like to be notified when a function a() has completed. The problem is that the function contains an ajax call and a loop that calls b(), which again contains an ajax call. UPDATED WITH FIDDLE: http://jsfiddle.net/hsyj7/1/ Like so: // called by main() function a() { return $.ajax("http://url1").pipe(function(data){ for (var i = 0; i < 2; i++) { console.log('a called'); b(); } }); } // called by a() function b() { for (var i = 0; i < 2; i++) { $.ajax("http:/

I have created my first deferred object in Node.js using deferred module and it works great when I pass result to next function and trigger resolve and reject.How to chain execution of array of functions when every function returns deferred.promise ? I have like input parameters array of functions and input parameter for first function and every next function get parameter from previous. It works like f1(100).then(f2).then(f3) , but how when I have n number of functions. You need to build a promise chain in a loop: var promise = funcs[0](input); for (var i = 1; i < funcs.length; i++) promise =