aiohttp/asyncio 多次请求

#!/usr/bin/env python# -*- coding: utf-8 -*-__author__ = "Daniel Altiparmak (sixfinger78@gmail.com)"__copyright__ = "Copyright (C) 2015 Daniel Altiparmak"__license__ = "GPL 3.0"import asyncioimport aiohttpimport tqdmimport stringimport random# get content and write it to filedef write_to_file(filename, content): ???f = open(filename, ‘wb‘) ???f.write(content) ???f.close()# a helper coroutine to perform GET requests:@asyncio.coroutinedef get(*args, **kwargs): ???response = yield from aiohttp.request(‘GET‘, *args, **kwargs) ???return (yield from response.read_and_close())@asyncio.coroutinedef download_file(url): ???# this routine is protected by a semaphore ???with (yield from r_semaphore): ???????content = yield from asyncio.async(get(url)) ???????# create random filename ???????length = 10 ???????file_string = ‘‘.join(random.choice( ???????????string.ascii_lowercase + string.digits) for _ in range(length) ?????????????????????????????) ???????filename = ‘{}.png‘.format(file_string) ???????write_to_file(filename, content)‘‘‘make nice progressbarinstall it by using `pip install tqdm`‘‘‘@asyncio.coroutinedef wait_with_progressbar(coros): ???for f in tqdm.tqdm(asyncio.as_completed(coros), total=len(coros)): ???????yield from fimages = [‘http://lorempixel.com/1920/1920/‘ for i in range(100)]# avoid to many requests(coroutines) the same time.# limit them by setting semaphores (simultaneous requests)r_semaphore = asyncio.Semaphore(10)coroutines = [download_file(url) for url in images]eloop = asyncio.get_event_loop()#eloop.run_until_complete(asyncio.wait(coroutines))eloop.run_until_complete(wait_with_progressbar(coroutines))eloop.close()