JavascriptWebworkers

WebWorkers

WebWorkers is a browser standard that allows you to use the extra CPU cores on the client.

To run this example run these commands in your shell:

cd
git clone https://github.com/rusthon/Rusthon.git
cd Rusthon/
./rusthon.py ./examples/javascript_webworkers.md

html

@index.html

<html>
<head>
</head>
<body>
<pre id="CONTAINER">
</pre>
<@myscript>
</body>
</html>

Webworker Syntax

The Javascript backend uses some syntax inspired by Golang to simplify using WebSockets. Below the class Worker must define a send method that takes a message and returns something to the main thread.

@myscript

#backend:javascript
from runtime import *

def show(txt):
    document.getElementById('CONTAINER').appendChild(
        document.createTextNode(txt + '\n')
    )

with webworker:
    class Worker():
        def send(self,ob):
            ## do some long computation here ##
            return ob

@debugger
def test():
    show('spawn workers')
    worker1 = spawn(
        Worker()
    )
    worker2 = spawn(
        Worker()
    )
    ## wait for awhile before sending messages ##
    window.setTimeout(
        lambda: test_workers(worker1,worker2),
        1500,
    )

def test_workers(worker1, worker2):
    show('sending data to workers')
    worker1 <- 'msg 1'
    worker1 <- 'msg 2'
    worker1 <- 'msg 3'
    worker1 <- 'msg 4'

    worker2 <- 'msg 5'
    worker2 <- 'msg 6'
    worker2 <- 'msg 7'
    worker2 <- 'msg 8'

    show('getting data from workers')
    res = <- worker1
    show('got first reply from worker')
    show(res)
    res = <- worker1
    show(res)
    res = <- worker1
    show(res)
    res = <- worker1
    show(res)

    res = <- worker2
    show(res)
    res = <- worker2
    show(res)
    res = <- worker2
    show(res)
    res = <- worker2
    show(res)

    show('ok')



window.setTimeout(test, 1000)