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()
|
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()
|
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()
|
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。