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"""
A model for a file downloader: Synchronous, Threaded and Asynchronous.
This version does not require an asynchronous command loop, so it works
on Windows too.
"""
import os, sys, cmd, time, threading
from ms.debug_utils import FifoWindow, TkWindow
from ms.async_utils import ThreadedLoopingCall, multi_iter
class Downloader(cmd.Cmd):
intro = "You may download the following files:\n%s" % \
"\n".join(f for f in os.listdir(".") if f.endswith(".html"))
out = TkWindow() # class level, since there is only one
def postloop(self):
self.out.close()
def do_quit(self, arg):
return True
def download(self, fname):
self.out.write("BEGIN %s" % fname)
for line in file(fname):
time.sleep(.1)
self.out.write(".")
self.out.write(" END %s\n" % fname)
class SynchronousDownloader(Downloader):
def do_download(self, arg):
self.download(arg)
class ThreadedDownloader(Downloader):
def do_download(self, arg):
self.thread = threading.Thread(target=self.download, args=(arg,))
self.thread.start()
def postloop(self):
self.thread.join() # wait for the thread to end before closing self.out
Downloader.postloop(self)
class QuasiAsynchronousDownloader(Downloader):
def preloop(self):
self.downloads = []
mi = multi_iter(self.downloads, terminate=False)
self.lc = ThreadedLoopingCall(mi.next)
self.lc.start()
def postloop(self):
self.lc.stop()
Downloader.postloop(self)
def do_download(self, arg):
self.downloads.append(self.download(arg))
def download(self, fname):
self.out.write("BEGIN %s" % fname)
for line in file(fname):
time.sleep(.1)
self.out.write(".")
yield None
self.out.write(" END %s\n" % fname)
if __name__ == "__main__":
#SynchronousDownloader().cmdloop()
ThreadedDownloader().cmdloop()
#QuasiAsynchronousDownloader().cmdloop()
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