安装Tornado
省事点可以直接用grequests库,下面用的是tornado的异步client。 异步用到了tornado,根据官方文档的例子修改得到一个简单的异步爬虫类。可以参考下最新的文档学习下。
pip install tornado
异步爬虫
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#!/usr/bin/env python
# -*- coding:utf-8 -*-
import time
from datetime import timedelta
from tornado import httpclient, gen, ioloop, queues
import traceback
class AsySpider( object ):
"""A simple class of asynchronous spider."""
def __init__( self , urls, concurrency = 10 , * * kwargs):
urls.reverse()
self .urls = urls
self .concurrency = concurrency
self ._q = queues.Queue()
self ._fetching = set ()
self ._fetched = set ()
def fetch( self , url, * * kwargs):
fetch = getattr (httpclient.AsyncHTTPClient(), 'fetch' )
return fetch(url, * * kwargs)
def handle_html( self , url, html):
"""handle html page"""
print (url)
def handle_response( self , url, response):
"""inherit and rewrite this method"""
if response.code = = 200 :
self .handle_html(url, response.body)
elif response.code = = 599 : # retry
self ._fetching.remove(url)
self ._q.put(url)
@gen .coroutine
def get_page( self , url):
try :
response = yield self .fetch(url)
print ( '######fetched %s' % url)
except Exception as e:
print ( 'Exception: %s %s' % (e, url))
raise gen.Return(e)
raise gen.Return(response)
@gen .coroutine
def _run( self ):
@gen .coroutine
def fetch_url():
current_url = yield self ._q.get()
try :
if current_url in self ._fetching:
return
print ( 'fetching****** %s' % current_url)
self ._fetching.add(current_url)
response = yield self .get_page(current_url)
self .handle_response(current_url, response) # handle reponse
self ._fetched.add(current_url)
for i in range ( self .concurrency):
if self .urls:
yield self ._q.put( self .urls.pop())
finally :
self ._q.task_done()
@gen .coroutine
def worker():
while True :
yield fetch_url()
self ._q.put( self .urls.pop()) # add first url
# Start workers, then wait for the work queue to be empty.
for _ in range ( self .concurrency):
worker()
yield self ._q.join(timeout = timedelta(seconds = 300000 ))
assert self ._fetching = = self ._fetched
def run( self ):
io_loop = ioloop.IOLoop.current()
io_loop.run_sync( self ._run)
class MySpider(AsySpider):
def fetch( self , url, * * kwargs):
"""重写父类fetch方法可以添加cookies,headers,timeout等信息"""
cookies_str = "PHPSESSID=j1tt66a829idnms56ppb70jri4; pspt=%7B%22id%22%3A%2233153%22%2C%22pswd%22%3A%228835d2c1351d221b4ab016fbf9e8253f%22%2C%22_code%22%3A%22f779dcd011f4e2581c716d1e1b945861%22%7D; key=%E9%87%8D%E5%BA%86%E5%95%84%E6%9C%A8%E9%B8%9F%E7%BD%91%E7%BB%9C%E7%A7%91%E6%8A%80%E6%9C%89%E9%99%90%E5%85%AC%E5%8F%B8; think_language=zh-cn; SERVERID=a66d7d08fa1c8b2e37dbdc6ffff82d9e|1444973193|1444967835; CNZZDATA1254842228=1433864393-1442810831-%7C1444972138" # 从浏览器拷贝cookie字符串
headers = {
'User-Agent' : 'mozilla/5.0 (compatible; baiduspider/2.0; +http://www.baidu.com/search/spider.html)' ,
'cookie' : cookies_str
}
return super (MySpider, self ).fetch( # 参数参考tornado文档
url, headers = headers, request_timeout = 1
)
def handle_html( self , url, html):
print (url, html)
def main():
urls = []
for page in range ( 1 , 100 ):
urls.append( 'http://www.baidu.com?page=%s' % page)
s = MySpider(urls)
s.run()
if __name__ = = '__main__' :
main()
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可以继承这个类,塞一些url进去,然后重写handle_page处理得到的页面。
异步+多进程爬虫
还可以再变态点,加个进程池,使用了multiprocessing模块。效率飕飕的,
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#!/usr/bin/env python
# -*- coding:utf-8 -*-
import time
from multiprocessing import Pool
from datetime import timedelta
from tornado import httpclient, gen, ioloop, queues
class AsySpider( object ):
"""A simple class of asynchronous spider."""
def __init__( self , urls, concurrency):
urls.reverse()
self .urls = urls
self .concurrency = concurrency
self ._q = queues.Queue()
self ._fetching = set ()
self ._fetched = set ()
def handle_page( self , url, html):
filename = url.rsplit( '/' , 1 )[ 1 ]
with open (filename, 'w+' ) as f:
f.write(html)
@gen .coroutine
def get_page( self , url):
try :
response = yield httpclient.AsyncHTTPClient().fetch(url)
print ( '######fetched %s' % url)
except Exception as e:
print ( 'Exception: %s %s' % (e, url))
raise gen.Return('')
raise gen.Return(response.body)
@gen .coroutine
def _run( self ):
@gen .coroutine
def fetch_url():
current_url = yield self ._q.get()
try :
if current_url in self ._fetching:
return
print ( 'fetching****** %s' % current_url)
self ._fetching.add(current_url)
html = yield self .get_page(current_url)
self ._fetched.add(current_url)
self .handle_page(current_url, html)
for i in range ( self .concurrency):
if self .urls:
yield self ._q.put( self .urls.pop())
finally :
self ._q.task_done()
@gen .coroutine
def worker():
while True :
yield fetch_url()
self ._q.put( self .urls.pop())
# Start workers, then wait for the work queue to be empty.
for _ in range ( self .concurrency):
worker()
yield self ._q.join(timeout = timedelta(seconds = 300000 ))
assert self ._fetching = = self ._fetched
def run( self ):
io_loop = ioloop.IOLoop.current()
io_loop.run_sync( self ._run)
def run_spider(beg, end):
urls = []
for page in range (beg, end):
urls.append( 'http://127.0.0.1/%s.htm' % page)
s = AsySpider(urls, 10 )
s.run()
def main():
_st = time.time()
p = Pool()
all_num = 73000
num = 4 # number of cpu cores
per_num, left = divmod (all_num, num)
s = range ( 0 , all_num, per_num)
res = []
for i in range ( len (s) - 1 ):
res.append((s[i], s[i + 1 ]))
res.append((s[ len (s) - 1 ], all_num))
print res
for i in res:
p.apply_async(run_spider, args = (i[ 0 ], i[ 1 ],))
p.close()
p.join()
print time.time() - _st
if __name__ = = '__main__' :
main()
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多线程爬虫
线程池实现.
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#!/usr/bin/env python
# -*- coding:utf-8 -*-
import Queue
import sys
import requests
import os
import threading
import time
class Worker(threading.Thread): # 处理工作请求
def __init__( self , workQueue, resultQueue, * * kwds):
threading.Thread.__init__( self , * * kwds)
self .setDaemon( True )
self .workQueue = workQueue
self .resultQueue = resultQueue
def run( self ):
while 1 :
try :
callable , args, kwds = self .workQueue.get( False ) # get task
res = callable ( * args, * * kwds)
self .resultQueue.put(res) # put result
except Queue.Empty:
break
class WorkManager: # 线程池管理,创建
def __init__( self , num_of_workers = 10 ):
self .workQueue = Queue.Queue() # 请求队列
self .resultQueue = Queue.Queue() # 输出结果的队列
self .workers = []
self ._recruitThreads(num_of_workers)
def _recruitThreads( self , num_of_workers):
for i in range (num_of_workers):
worker = Worker( self .workQueue, self .resultQueue) # 创建工作线程
self .workers.append(worker) # 加入到线程队列
def start( self ):
for w in self .workers:
w.start()
def wait_for_complete( self ):
while len ( self .workers):
worker = self .workers.pop() # 从池中取出一个线程处理请求
worker.join()
if worker.isAlive() and not self .workQueue.empty():
self .workers.append(worker) # 重新加入线程池中
print 'All jobs were complete.'
def add_job( self , callable , * args, * * kwds):
self .workQueue.put(( callable , args, kwds)) # 向工作队列中加入请求
def get_result( self , * args, * * kwds):
return self .resultQueue.get( * args, * * kwds)
def download_file(url):
#print 'beg download', url
requests.get(url).text
def main():
try :
num_of_threads = int (sys.argv[ 1 ])
except :
num_of_threads = 10
_st = time.time()
wm = WorkManager(num_of_threads)
print num_of_threads
urls = [ 'http://www.baidu.com' ] * 1000
for i in urls:
wm.add_job(download_file, i)
wm.start()
wm.wait_for_complete()
print time.time() - _st
if __name__ = = '__main__' :
main()
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这三种随便一种都有很高的效率,但是这么跑会给网站服务器不小的压力,尤其是小站点,还是有点节操为好。