我刚开始使用ASYNCIO,我想用它来分析一个网站。
我试图解析该网站的6段(self.signals
),每个部分有与他们的表页N多,所以基本上我想异步调用哪个部分的循环,异步在每个部分的页面。这是我到目前为止所。
class FinViz():
def __init__(self):
self.url = 'https://finviz.com/screener.ashx?v=160&s='
self.signals = {
'Earnings_Before' : 'n_earningsbefore',
'Earnings_After' : 'n_earningsafter',
'Most_Active' : 'ta_mostactive',
'Top_Gainers' : 'ta_topgainers',
'Most_Volatile' : 'ta_mostvolatile',
'News' : 'n_majornews',
'Upgrade' : 'n_upgrades',
'Unusual_Volume' : 'ta_unusualvolume'
}
self.ticks = []
def _parseTable(self, data):
i, signal = data
url = self.signals[signal] if i == 0 else self.signals[signal] + '&r={}'.format(str(i * 20 + 1))
soup = BeautifulSoup(urlopen(self.url + url, timeout = 3).read(), 'html5lib')
table = soup.find('div', {'id' : 'screener-content'}).find('table',
{'width' : '100%', 'cellspacing': '1', 'cellpadding' : '3', 'border' : '0', 'bgcolor' : '#d3d3d3'})
for row in table.findAll('tr'):
col = row.findAll('td')[1]
if col.find('a'):
self.ticks.append(col.find('a').text)
async def parseSignal(self, signal):
try:
soup = BeautifulSoup(urlopen(self.url + self.signals[signal], timeout = 3).read(), 'html5lib')
tot = int(soup.find('td', {'class' : 'count-text'}).text.split()[1])
with concurrent.futures.ThreadPoolExecutor(max_workers = 20) as executor:
loop = asyncio.get_event_loop()
futures = []
for i in range(tot // 20 + (tot % 20 > 0)):
futures.append(loop.run_in_executor(executor, self._parseTable, (i, signal)))
for response in await asyncio.gather(*futures):
pass
except URLError:
pass
async def getAll(self):
with concurrent.futures.ThreadPoolExecutor(max_workers = 20) as executor:
loop = asyncio.get_event_loop()
futures = []
for signal in self.signals:
futures.append(await loop.run_in_executor(executor, self.parseSignal, signal))
for response in await asyncio.gather(*futures):
pass
print(self.ticks)
if __name__ == '__main__':
x = FinViz()
loop = asyncio.get_event_loop()
loop.run_until_complete(x.getAll())
这确实成功地做工作,但它在某种程度上确实比如果我是做解析,而不asyncio
慢。
任何提示的异步菜鸟?
编辑:添加完整的代码
记住Python有一个GIL,所以线程代码不会帮助提高性能。潜在的加快速度使用ProcessPoolExecutor但是请注意,你就导致了以下开销:
你能避免1.如果你在叉子上的安全环境中运行,数据存储在一个全局变量。
你也可以做的东西一样共享内存映射文件...还共享原始字符串/字节是最快的。