On 7 Nov 2009, at 18:37, inhahe wrote:
i don't understand this at all
i hope you will provide a basic explanation of what we're doing for
us simpletons :P
Sure, but next time could you ask a more precise question? ;-)
# Create a pool of threads to execute calls.
with futures.ThreadPoolExecutor(max_threads=5) as executor:
# Schedule the given calls to run using the thread pool created
above and
# return a FutureList (a list of Futures + some convenience
methods). Called
# without the "return_when" argument, waits until all calls are
complete.
futures_list = executor.run_to_futures(...)
# Iterate through every Future. A Future represents one of the
asynchronous
# calls.
for url, future in zip(URLS, future_list):
# Check if the call raised an exception.
if future.exception() is not None:
# Print the exception
print('%r generated an exception: %s' % (url, future.exception()))
else:
# The call returned successfully so future.result() contains the
return
# value.
print('%r page is %d bytes' % (url, len(future.result())))
Cheers,
Brian
import futures
import functools
import urllib.request
URLS = [
'http://www.foxnews.com/',
'http://www.cnn.com/',
'http://europe.wsj.com/',
'http://www.bbc.co.uk/',
'http://some-made-up-domain.com/']
def load_url(url, timeout):
return urllib.request.urlopen(url, timeout=timeout).read()
# Use a thread pool with 5 threads to download the URLs. Using a pool
# of processes would involve changing the initialization to:
# with futures.ProcessPoolExecutor(max_processes=5) as executor
with futures.ThreadPoolExecutor(max_threads=5) as executor:
future_list = executor.run_to_futures(
[functools.partial(load_url, url, 30) for url in URLS])
# Check the results of each future.
for url, future in zip(URLS, future_list):
if future.exception() is not None:
print('%r generated an exception: %s' % (url,
future.exception()))
else:
print('%r page is %d bytes' % (url, len(future.result())))
In this example, executor.run_to_futures() returns only when every
url has been retrieved but it is possible to return immediately, on
the first completion or on the first failure depending on the
desired work pattern.
The complete docs are here:
http://sweetapp.com/futures/
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