Example of Retrying promise n times with timeout (not tested yet!) (Idea taken from http://stackoverflow.com/questions/21146856/using-the-q-implementation-in-angular-how-can-i-loop-a-promise-until-success)

retrying_promise.js

var express = require('express');
var app = express();
var q = require('q');

function retryingPromise(fn, cfg, times) {
    var counter = 0;
    var delay = 0;
    var _times = times ? times : 2;
    var _step = _step ? step : 1000;
    var _cfg = cfg ? cfg : {};
    var deferred = q.defer();

    var makeRequest = function (__cfg) {
        var args = arguments;
        counter++;
        delay += _step;
        var self = this;

        fn(__cfg).then(function(result) {
            deferred.resolve(result);
        }, function(e) {
            if(counter >= _times) {
                console.log("DEBUG retryPromise fails with counter (",counter,") and error: ", e);
                return deferred.reject(e);
            }
            setTimeout(function() {
                makeRequest.apply(self, args);
            }, delay);
        });
    };
    makeRequest(_cfg);
    return deferred.promise;
}

function dummyPromise(opts) {
	if(opts.id < 4) {
		return q.reject("ko");
	} else {
		return q.when("ok");
	}
}

app.get('/test-promise', function(req, res, next) {
	var params = req.query;
	console.log("get /test-promise con params: ", params);
	retryingPromise(dummyPromise, {id: params.id}, 4).then(function(r) {
		console.log("DEBUG dummyPromise ok -> ", r);
		res.end(r);
	}).catch(function(e) {
		console.log("DEBUG dummyPromise catch! ", e);
		res.status = 500;
		res.end(e);
	});
});

var server = app.listen(5000, function() {
	var port = server.address().port;
	console.log("Server running on port: ",port);
});