将任务添加到python asyncio

我想编写一个简单的网络爬虫为了测试新的asyncio模块如何工作，但有一些我错了。我正尝试使用单个网址启动抓取工具。该脚本应该下载该页面，在页面上找到任何<a>标签，并安排它们也要下载。我期望的输出是一串行，表示第一页已经被下载，随后的页面以随机顺序（即，下载完成）完成，但实际上它们只是按顺序下载。我完全陌生于异步一般和这个模块，所以我确定只有一些基本概念，我错过了。将任务添加到python asyncio

这是到目前为止我的代码：

import asyncio 
import re 
import requests 
import time 
from bs4 import BeautifulSoup 
from functools import partial 

@asyncio.coroutine 
def get_page(url, depth=0): 
    print('%s: Getting %s' % (time.time(), url)) 
    page = requests.get(url) 
    print('%s: Got %s' % (time.time(), url)) 
    soup = BeautifulSoup(page.text) 
    if depth < 2: 
     for a in soup.find_all('a', href=re.compile(r'\w+\.html'))[:3]: 
      u = 'https://docs.python.org/3/' + a['href'] 
      print('%s: Scheduling %s' % (time.time(), u)) 
      yield from get_page(u, depth+1) 
    if depth == 0: 
     loop.stop() 
    return soup 

root = 'https://docs.python.org/3/' 
loop = asyncio.get_event_loop() 
loop.create_task(get_page(root)) 
loop.run_forever()

这里是输出：

1434971882.3458219: Getting https://docs.python.org/3/ 
1434971893.0054126: Got https://docs.python.org/3/ 
1434971893.015218: Scheduling https://docs.python.org/3/genindex.html 
1434971893.0153584: Getting https://docs.python.org/3/genindex.html 
1434971894.464993: Got https://docs.python.org/3/genindex.html 
1434971894.4752269: Scheduling https://docs.python.org/3/py-modindex.html 
1434971894.4753256: Getting https://docs.python.org/3/py-modindex.html 
1434971896.9845033: Got https://docs.python.org/3/py-modindex.html 
1434971897.0756354: Scheduling https://docs.python.org/3/index.html 
1434971897.0757186: Getting https://docs.python.org/3/index.html 
1434971907.451529: Got https://docs.python.org/3/index.html 
1434971907.4600112: Scheduling https://docs.python.org/3/genindex-Symbols.html 
1434971907.4600625: Getting https://docs.python.org/3/genindex-Symbols.html 
1434971917.6517148: Got https://docs.python.org/3/genindex-Symbols.html 
1434971917.6789174: Scheduling https://docs.python.org/3/py-modindex.html 
1434971917.6789672: Getting https://docs.python.org/3/py-modindex.html 
1434971919.454042: Got https://docs.python.org/3/py-modindex.html 
1434971919.574361: Scheduling https://docs.python.org/3/genindex.html 
1434971919.574434: Getting https://docs.python.org/3/genindex.html 
1434971920.5942516: Got https://docs.python.org/3/genindex.html 
1434971920.6020699: Scheduling https://docs.python.org/3/index.html 
1434971920.6021295: Getting https://docs.python.org/3/index.html 
1434971922.1504402: Got https://docs.python.org/3/index.html 
1434971922.1589775: Scheduling https://docs.python.org/3/library/__future__.html#module-__future__ 
1434971922.1590302: Getting https://docs.python.org/3/library/__future__.html#module-__future__ 
1434971923.30988: Got https://docs.python.org/3/library/__future__.html#module-__future__ 
1434971923.3215268: Scheduling https://docs.python.org/3/whatsnew/3.4.html 
1434971923.321574: Getting https://docs.python.org/3/whatsnew/3.4.html 
1434971926.6502898: Got https://docs.python.org/3/whatsnew/3.4.html 
1434971926.89331: Scheduling https://docs.python.org/3/../genindex.html 
1434971926.8934016: Getting https://docs.python.org/3/../genindex.html 
1434971929.0996494: Got https://docs.python.org/3/../genindex.html 
1434971929.1068246: Scheduling https://docs.python.org/3/../py-modindex.html 
1434971929.1068716: Getting https://docs.python.org/3/../py-modindex.html 
1434971932.5949798: Got https://docs.python.org/3/../py-modindex.html 
1434971932.717457: Scheduling https://docs.python.org/3/3.3.html 
1434971932.7175465: Getting https://docs.python.org/3/3.3.html 
1434971934.009238: Got https://docs.python.org/3/3.3.html

来源

2015-06-22 aquavitae

使用ASYNCIO不会奇迹般地使你的所有代码异步的。在这种情况下，requests被阻塞，所以你所有的协同程序都会等待它。

有一个称为aiohttp的异步库允许异步http请求，虽然它不像requests那样用户友好。

来源

2015-06-22 11:29:12

将任务添加到python asyncio

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