Generate oAuth nonce for parallel requests

问题:

I am requesting Bitstamp API in parrallel:

// Simplified version

var async = require('async');
var bitstamp = require('bitstamp');

async.parallel([
    bitstamp.balance,
    bitstamp.ticker
    // ...
],
function() (err, result) {
    // process results
});

Those two methods are sending signed requests to Bitstamp API including nonce.

Nonce is a regular integer number. It must be increasing with every request you make. Read more about it here. Example: if you set nonce to 1 in your first request, you must set it to at least 2 in your second request. You are not required to start with 1. A common practice is to use unix time for that parameter.

Underlying library generates nonce traditional way:

var nonce = new Date().getTime() + '' + new Date().getMilliseconds();

Problem

Because of asynchronous API calls, sometimes nonce generated it very same millisecond, while remote side wants them increasing.

Question

Keeping parallel requests, any idea to reliably generate sequential nonce?

My obvious try to:

this.nonce = new Date().getTime() + '' + new Date().getMilliseconds(); 
// ... on request
var nonce = this.nonce++;

But it doesn't solve the problem, same millisecond just increased by one, but still equal.

回答1:

(author of the npm module here)

I solved it by adding my own counter at the end of the ms timestamp. It now supports up to 999 calls per ms because of this function. The first time it will generate something like 1409074885767000 and if you need a new nonce during the same ms it will then generate 1409074885767001, 1409074885767002, ...

回答2:

I had exactly the same problem, so I took askmike's code and modified it slightly.

var nonce = new (function() {

    this.generate = function() {

        var now = Date.now();

        this.counter = (now === this.last? this.counter + 1 : 0);
        this.last    = now;

        // add padding to nonce
        var padding = 
            this.counter < 10 ? '000' : 
                this.counter < 100 ? '00' :
                    this.counter < 1000 ?  '0' : '';

        return now+padding+this.counter;
    };
})();

use it like this

nonce.generate();

check out my jsfiddle with example

回答3:

npm nonce module is now generate it correctly