Tiny WebWorker for Server
npm install tiny-workerrequire() is available for flexible inline Worker scripts. Optional parameters args Array & options Object; see child_process.fork() documentation.
javascript
onmessage = function (ev) {
postMessage(ev.data);
};
`
The core script:
`javascript
var Worker = require("tiny-worker");
var worker = new Worker("repeat.js");
worker.onmessage = function (ev) {
console.log(ev.data);
worker.terminate();
};
worker.postMessage("Hello World!");
`
#### Enable ES6 import/export within Worker file
The worker helper script (helper.js):
`javascript
export const dataFormatter = (data) => {
return ${data} World!;
};
`
The worker script (repeat.js):
`javascript
import { dataFormatter } from "./helper";
onmessage = function (ev) {
const data = dataFormatter(ev.data);
postMessage(data);
};
`
The core script:
`javascript
var Worker = require("tiny-worker");
var worker = new Worker("repeat.js", [], {esm: true});
worker.onmessage = function (ev) {
console.log(ev.data);
worker.terminate();
};
worker.postMessage("Hello");
`
#### Creating a Worker from a Function
`javascript
var Worker = require("tiny-worker");
var worker = new Worker(function () {
self.onmessage = function (ev) {
postMessage(ev.data);
};
});
worker.onmessage = function (ev) {
console.log(ev.data);
worker.terminate();
};
worker.postMessage("Hello World!");
`
Debugging
To be able to debug a child process, it must have a differnt debug port than the parent.
Tiny worker does this by adding a random port within a range to the parents debug port.
The default Range is [1, 300], it can be changed with the setRange(min, max) method.
To disable any automatic port redirection set options.noDebugRedirection = true.
$3
`javascript
//parent is started with '--debug=1234'
var Worker = require("tiny-worker");
Worker.setRange(2, 20);
var worker = new Worker(function () {
postMessage(process.debugPort);
});
worker.onmessage = function (ev) {
console.log(ev.data); //prints any number between 1236 and 1254
worker.terminate();
}
`
$3
`javascript
//parent is started with '--debug=1234'
var Worker = require("tiny-worker");
var worker = new Worker(function () {
postMessage(process.debugPort);
}, [], {noDebugRedirection: true, execArgv: ["--debug=1235"]});
worker.onmessage = function (ev) {
console.log(ev.data); //prints 1235
worker.terminate();
}
`
Properties
#### onmessage
Message handler, accepts an Event
#### onerror
Error handler, accepts an Event
API
#### addEventListener(event, fn)
Adds an event listener
#### postMessage()
Broadcasts a message to the Worker
#### terminate()
Terminates the Worker
#### static setRange(min, max)
Sets range for debug ports, only affects current process.
Returns true if successful.
FAQ
1. I have an orphaned child process that lives on past the parent process' lifespan
* Most likely a SIGTERM or SIGINT is not reaching the child process
2. How do I insure all process are terminated?
* In your core script register a listener for SIGTERM or SIGINT via process.on() which terminates (all) worker process(es) and then gracefully shutdowns via process.exit(0);
3. Why SIGTERM or SIGINT?
* Unix/BSD will work with SIGTERM, but if you also need to support Windows use SIGINT`