在进行网络爬虫时，会经常有封ip的现象。可以使用代理池来进行代理ip的处理。
代理池的要求：多站抓取，异步检测。定时筛选，持续更新。提供接口，易于提取。
代理池架构：获取器，过滤器，代理队列，定时检测。
使用https://github.com/Germey/ProxyPool/tree/master/proxypool代码进行分析。
run.py里面的代码
from proxypool.api import app
from proxypool.schedule import Schedule
def main():
s = Schedule()
s.run()
app.run()
if __name__ == '__main__':
main()首先运行了一个调度器，接着运行了一个接口。
调度器schedule.py代码
import time
from multiprocessing import Process
import asyncio
import aiohttp
try:
from aiohttp.errors import ProxyConnectionError,ServerDisconnectedError,ClientResponseError,ClientConnectorError
except:
from aiohttp import ClientProxyConnectionError as ProxyConnectionError,ServerDisconnectedError,ClientResponseError,ClientConnectorError
from proxypool.db import RedisClient
from proxypool.error import ResourceDepletionError
from proxypool.getter import FreeProxyGetter
from proxypool.setting import *
from asyncio import TimeoutError
class ValidityTester(object):
test_api = TEST_API
def __init__(self):
self._raw_proxies = None
self._usable_proxies = []
def set_raw_proxies(self, proxies):
self._raw_proxies = proxies
self._conn = RedisClient()
async def test_single_proxy(self, proxy):
"""
text one proxy, if valid, put them to usable_proxies.
"""
try:
async with aiohttp.ClientSession() as session:
try:
if isinstance(proxy, bytes):
proxy = proxy.decode('utf-8')
real_proxy = 'http://' + proxy
print('Testing', proxy)
async with session.get(self.test_api, proxy=real_proxy, timeout=get_proxy_timeout) as response:
if response.status == 200:
self._conn.put(proxy)
print('Valid proxy', proxy)
except (ProxyConnectionError, TimeoutError, ValueError):
print('Invalid proxy', proxy)
except (ServerDisconnectedError, ClientResponseError,ClientConnectorError) as s:
print(s)
pass
def test(self):
"""
aio test all proxies.
"""
print('ValidityTester is working')
try:
loop = asyncio.get_event_loop()
tasks = [self.test_single_proxy(proxy) for proxy in self._raw_proxies]
loop.run_until_complete(asyncio.wait(tasks))
except ValueError:
print('Async Error')
class PoolAdder(object):
"""
add proxy to pool
"""
def __init__(self, threshold):
self._threshold = threshold
self._conn = RedisClient()
self._tester = ValidityTester()
self._crawler = FreeProxyGetter()
def is_over_threshold(self):
"""
judge if count is overflow.
"""
if self._conn.queue_len >= self._threshold:
return True
else:
return False
def add_to_queue(self):
print('PoolAdder is working')
proxy_count = 0
while not self.is_over_threshold():
for callback_label in range(self._crawler.__CrawlFuncCount__):
callback = self._crawler.__CrawlFunc__[callback_label]
raw_proxies = self._crawler.get_raw_proxies(callback)
# test crawled proxies
self._tester.set_raw_proxies(raw_proxies)
self._tester.test()
proxy_count += len(raw_proxies)
if self.is_over_threshold():
print('IP is enough, waiting to be used')
break
if proxy_count == 0:
raise ResourceDepletionError
class Schedule(object):
@staticmethod
def valid_proxy(cycle=VALID_CHECK_CYCLE):
"""
Get half of proxies which in redis
"""
conn = RedisClient()
tester = ValidityTester()
while True:
print('Refreshing ip')
count = int(0.5 * conn.queue_len)
if count == 0:
print('Waiting for adding')
time.sleep(cycle)
continue
raw_proxies = conn.get(count)
tester.set_raw_proxies(raw_proxies)
tester.test()
time.sleep(cycle)
@staticmethod
def check_pool(lower_threshold=POOL_LOWER_THRESHOLD,
upper_threshold=POOL_UPPER_THRESHOLD,
cycle=POOL_LEN_CHECK_CYCLE):
"""
If the number of proxies less than lower_threshold, add proxy
"""
conn = RedisClient()
adder = PoolAdder(upper_threshold)
while True:
if conn.queue_len < lower_threshold:
adder.add_to_queue()
time.sleep(cycle)
def run(self):
print('Ip processing running')
valid_process = Process(target=Schedule.valid_proxy)
check_process = Process(target=Schedule.check_pool)
valid_process.start()
check_process.start()调度器里面有个run方法，里面运行了两个进程。一个进程valid_process是从网上获取代理放入数据库；另外一个进程check_process是定时的从数据库拿出代理进行检测。
valid_proxy是定时检测器，里面传入一个时间的参数cycle=VALID_CHECK_CYCLE，定义定时检测的时间。方法里首先定义一个RedisClient()进行数据库的连接，该方法定义在db.py中
import redis
from proxypool.error import PoolEmptyError
from proxypool.setting import HOST, PORT, PASSWORD
class RedisClient(object):
def __init__(self, host=HOST, port=PORT):
if PASSWORD:
self._db = redis.Redis(host=host, port=port, password=PASSWORD)
else:
self._db = redis.Redis(host=host, port=port)
def get(self, count=1):
"""
get proxies from redis
"""
#从左侧批量获取的方法
proxies = self._db.lrange("proxies", 0, count - 1)
self._db.ltrim("proxies", count, -1)
return proxies
def put(self, proxy):
"""
add proxy to right top
"""
self._db.rpush("proxies", proxy)
def pop(self):
"""
get proxy from right.
"""
try:
return self._db.rpop("proxies").decode('utf-8')
except:
raise PoolEmptyError
@property
def queue_len(self):
"""
get length from queue.
"""
return self._db.llen("proxies")
def flush(self):
"""
flush db
"""
self._db.flushall()
if __name__ == '__main__':
conn = RedisClient()
print(conn.pop())接着还声明了ValidityTester()，用来检测代理是否可用，其中的test_single_proxy（）方法是实现异步检测的关键。
check_pool（）方法里面需要传入三个参数：两个代理池的上下界限，一个时间。里面有个PoolAdder的add_to_queue()方法。add_to_queue()方法中使用了一个从网站抓取ip的类FreeProxyGetter()，在getter.py里面from .utils import get_page
from pyquery import PyQuery as pq
import re
class ProxyMetaclass(type):
"""
元类，在FreeProxyGetter类中加入
__CrawlFunc__和__CrawlFuncCount__
两个参数，分别表示爬虫函数，和爬虫函数的数量。
"""
def __new__(cls, name, bases, attrs):
count = 0
attrs['__CrawlFunc__'] = []
for k, v in attrs.items():
if 'crawl_' in k:
attrs['__CrawlFunc__'].append(k)
count += 1
attrs['__CrawlFuncCount__'] = count
return type.__new__(cls, name, bases, attrs)
class FreeProxyGetter(object, metaclass=ProxyMetaclass):
def get_raw_proxies(self, callback):
proxies = []
print('Callback', callback)
for proxy in eval("self.{}()".format(callback)):
print('Getting', proxy, 'from', callback)
proxies.append(proxy)
return proxies
def crawl_ip181(self):
start_url = 'http://www.ip181.com/'
html = get_page(start_url)
ip_adress = re.compile('<tr.*?>\s*<td>(.*?)</td>\s*<td>(.*?)</td>')
# \s* 匹配空格，起到换行作用
re_ip_adress = ip_adress.findall(html)
for adress, port in re_ip_adress:
result = adress + ':' + port
yield result.replace(' ', '')
def crawl_kuaidaili(self):
for page in range(1, 4):
# 国内高匿代理
start_url = 'https://www.kuaidaili.com/free/inha/{}/'.format(page)
html = get_page(start_url)
ip_adress = re.compile(
'<td data-title="IP">(.*)</td>\s*<td data-title="PORT">(\w+)</td>'
)
re_ip_adress = ip_adress.findall(html)
for adress, port in re_ip_adress:
result = adress + ':' + port
yield result.replace(' ', '')
def crawl_xicidaili(self):
for page in range(1, 4):
start_url = 'http://www.xicidaili.com/wt/{}'.format(page)
html = get_page(start_url)
ip_adress = re.compile(
'<td class="country"><img src="http://fs.xicidaili.com/images/flag/cn.png" alt="Cn" /></td>\s*<td>(.*?)</td>\s*<td>(.*?)</td>'
)
# \s* 匹配空格，起到换行作用
re_ip_adress = ip_adress.findall(html)
for adress, port in re_ip_adress:
result = adress + ':' + port
yield result.replace(' ', '')
def crawl_daili66(self, page_count=4):
start_url = 'http://www.66ip.cn/{}.html'
urls = [start_url.format(page) for page in range(1, page_count + 1)]
for url in urls:
print('Crawling', url)
html = get_page(url)
if html:
doc = pq(html)
trs = doc('.containerbox table tr:gt(0)').items()
for tr in trs:
ip = tr.find('td:nth-child(1)').text()
port = tr.find('td:nth-child(2)').text()
yield ':'.join([ip, port])
def crawl_data5u(self):
for i in ['gngn', 'gnpt']:
start_url = 'http://www.data5u.com/free/{}/index.shtml'.format(i)
html = get_page(start_url)
ip_adress = re.compile(
' <ul class="l2">\s*<span><li>(.*?)</li></span>\s*<span style="width: 100px;"><li class=".*">(.*?)</li></span>'
)
# \s * 匹配空格，起到换行作用
re_ip_adress = ip_adress.findall(html)
for adress, port in re_ip_adress:
result = adress + ':' + port
yield result.replace(' ', '')
def crawl_kxdaili(self):
for i in range(1, 4):
start_url = 'http://www.kxdaili.com/ipList/{}.html#ip'.format(i)
html = get_page(start_url)
ip_adress = re.compile('<tr.*?>\s*<td>(.*?)</td>\s*<td>(.*?)</td>')
# \s* 匹配空格，起到换行作用
re_ip_adress = ip_adress.findall(html)
for adress, port in re_ip_adress:
result = adress + ':' + port
yield result.replace(' ', '')
def crawl_premproxy(self):
for i in ['China-01', 'China-02', 'China-03', 'China-04', 'Taiwan-01']:
start_url = 'https://premproxy.com/proxy-by-country/{}.htm'.format(
i)
html = get_page(start_url)
if html:
ip_adress = re.compile('<td data-label="IP:port ">(.*?)</td>')
re_ip_adress = ip_adress.findall(html)
for adress_port in re_ip_adress:
yield adress_port.replace(' ', '')
def crawl_xroxy(self):
for i in ['CN', 'TW']:
start_url = 'http://www.xroxy.com/proxylist.php?country={}'.format(
i)
html = get_page(start_url)
if html:
ip_adress1 = re.compile(
"title='View this Proxy details'>\s*(.*).*")
re_ip_adress1 = ip_adress1.findall(html)
ip_adress2 = re.compile(
"title='Select proxies with port number .*'>(.*)</a>")
re_ip_adress2 = ip_adress2.findall(html)
for adress, port in zip(re_ip_adress1, re_ip_adress2):
adress_port = adress + ':' + port
yield adress_port.replace(' ', '')具体使用方法可以看GitHub。。。。。。来源：oschina
链接：https://my.oschina.net/u/4339513/blog/3861255