#!/usr/bin/python
"""Run asynchronous tasks with gobject and coroutines."""
import gobject
def start_job(generator):
"""Start a job (a coroutine that yield tasks)."""
def _task_return(result):
def _advance_generator():
try:
new_task = generator.send(result)
except StopIteration:
return
new_task(_task_return)
# isolate the advance of the coroutine
gobject.idle_add(_advance_generator)
_task_return(None)
return generator
# Task examples
def sleep_task(secs):
"""Suspend job for the given number of seconds and return elapsed time."""
def _task(task_return):
start_time = time.time()
def _on_timeout():
task_return(time.time() - start_time)
gobject.timeout_add(int(secs * 1000), _on_timeout)
return _task
from threading import Thread
from Queue import Queue
def threaded_task(function, *args, **kwargs):
"""Run function(*args, **kwargs) in a thread and return the value."""
def _task(task_return):
def _thread(queue):
queue.put(function(*args, **kwargs))
def _manager(queue):
if queue.empty():
return True
task_return(queue.get())
queue = Queue()
thread = Thread(target=_thread, args=(queue,))
thread.setDaemon(True)
thread.start()
gobject.timeout_add(100, _manager, queue)
return _task
###
import sys
import time
import random
import urllib2
def myjob(url):
def download(url):
return urllib2.urlopen(url).read()
sys.stderr.write("[sleep]")
elapsed = yield sleep_task(random.uniform(0.0, 3.0))
sys.stderr.write("[sleep_done:%0.2f]" % elapsed)
sys.stderr.write("[download:%s]" % url)
html = yield threaded_task(download, url)
sys.stderr.write("[HTML:%s:%d]" % (url, len(html)))
def basso_continuo():
sys.stderr.write(".")
return True
urls = ["http://www.google.com", "http://python.com", "http://www.pygtk.org"]
for url in urls:
start_job(myjob(url))
gobject.timeout_add(100, basso_continuo)
gobject.threads_init() # only needed if you use threaded tasks
loop = gobject.MainLoop()
loop.run() # or gtk.main()
Diff to Previous Revision
--- revision 17 2010-04-24 22:42:56
+++ revision 18 2010-04-25 23:04:58
@@ -71,6 +71,6 @@
for url in urls:
start_job(myjob(url))
gobject.timeout_add(100, basso_continuo)
-gobject.threads_init() # only needed if you don't use threaded tasks
+gobject.threads_init() # only needed if you use threaded tasks
loop = gobject.MainLoop()
loop.run() # or gtk.main()