Server Web Workers for node.js that work
npm install workerjsServer Web Workers for node.js that work.
This module is installed via npm:
`` bash`
$ npm install workerjs
Web Workers are part of the HTML 5 spec and:
> defines an API that allows Web application authors to spawn background workers
> running scripts in parallel to their main page. This allows for thread-like
> operation with message-passing as the coordination mechanism
In effect, it allows you to get the benefit of multi-talking and multi-threading
in single-threaded Javascript, as well as the safety of the event loop.
You can achieve this in node.js using the child_process.fork method, but then
you have to use a different API.
This module normalizes the Web Worker API for server-side javascript in node.js
with the hopes that we can build more multi-tasking modules built on the
Web Worker standard that will work on both the server and the client-side
using browserify.
By using Web Workers you can do CPU-intensive operations without blocking
the event-loop and incoming IO:
` js`
// app.js - run with "node app.js"
var worker = new Worker('/path/to/fibworker.js');
worker.onmessage = function (msg) {
expect(msg.data).to.equal(1346269);
};
worker.postMessage(30);
` js
// fibworker.js - CPU web worker code
self.onmessage = function (msg) {
self.postMessage(fibo(msg.data));
};
function fibo (n) {
return n > 1 ? fibo(n - 1) + fibo(n - 2) : 1;
}
`
I've also added a "node-friendly" option that allows the Web Worker to use
require() and other node.js conventions. To use this, just pass a boolean
value of true through to the second argument of the Worker contructor:
` js`
// app.js - run with "node app.js"
var worker = new Worker('/path/to/gammaworker.js', true);
worker.addEventListener('message', function (msg) {
expect(msg.data).to.equal(87178291200.00021);
done();
});
worker.postMessage(15);
` js`
// gammaworker.js - uses require
var gamma = require('gamma');
self.onmessage = function (msg) {
postMessage(gamma(msg.data));
};
Also, if you provide a `module.exports` function it will be executed as
an entry point of the web worker. This emulates the browserify transform
behaviour in webworkify:
` js`
// app.js - run with "node app.js"
var worker = new Worker('/path/to/gammaworker2.js', true);
worker.addEventListener('message', function (msg) {
expect(msg.data).to.equal(87178291200.00021);
done();
});
worker.postMessage(15);
` js
// gammaworker2.js - uses require
var gamma = require('gamma');
module.exports = function () {
postMessage(gamma(msg.data));
};
``