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小编给大家分享一下Python3中元类属性怎么用，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！
元类属性的使用
代码
主要关于元类的使用
通过获取由元类生成的爬虫抓取类的部分属性.这里为抓取函数,以相同的字符开头的抓取函数,生成属性列表,这样可以持续调用.目的是可以仅仅添加不同的抓取函数抓取不同的网站,而类的其他部分不用做调整.
部分代码:
class ProxyMetaclass(type):
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 Crawler(object, metaclass=ProxyMetaclass):
def get_proxies(self, callback):
proxies = []
for proxy in eval("self.{}()".format(callback)):
print('成功获取到代理', proxy)
proxies.append(proxy)
return proxies
def crawl_daili66(self, page_count=4):
"""
获取代理66
:param page_count: 页码
:return: 代理
"""
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])测试方法
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time : 12/19/19 4:10 PM
# @Author : yon
# @Email : @qq.com
# @File : test
import json
import re
from pyquery import PyQuery as pq
class ProxyMetaclass(type):
def __new__(cls, name, bases, attrs):
count = 0
attrs['__CrawlFunc__'] = []
for k, v in attrs.items():
print("打印k")
print(k)
print("打印v")
print(v)
if 'crawl_' in k:
attrs['__CrawlFunc__'].append(k)
count += 1
attrs['__CrawlFuncCount__'] = count
return type.__new__(cls, name, bases, attrs)
class Crawler(object, metaclass=ProxyMetaclass):
def get_proxies(self, callback):
proxies = []
for proxy in eval("self.{}()".format(callback)):
print('成功获取到代理', proxy)
proxies.append(proxy)
return proxies
def crawl_daili66(self, page_count=4):
"""
获取代理66
:param page_count: 页码
:return: 代理
"""
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_ip3366(self):
for page in range(1, 4):
start_url = 'http://www.ip3366.net/free/?stype=1&page={}'.format(page)
html = get_page(start_url)
ip_address = re.compile('<tr>\s*<td>(.*?)</td>\s*<td>(.*?)</td>')
# \s * 匹配空格，起到换行作用
re_ip_address = ip_address.findall(html)
for address, port in re_ip_address:
result = address + ':' + port
yield result.replace(' ', '')
def crawl_kuaidaili(self):
for i in range(1, 4):
start_url = 'http://www.kuaidaili.com/free/inha/{}/'.format(i)
html = get_page(start_url)
if html:
ip_address = re.compile('<td data-title="IP">(.*?)</td>')
re_ip_address = ip_address.findall(html)
port = re.compile('<td data-title="PORT">(.*?)</td>')
re_port = port.findall(html)
for address, port in zip(re_ip_address, re_port):
address_port = address + ':' + port
yield address_port.replace(' ', '')
def crawl_xicidaili(self):
for i in range(1, 3):
start_url = 'http://www.xicidaili.com/nn/{}'.format(i)
headers = {
'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8',
'Cookie': '_free_proxy_session=BAh7B0kiD3Nlc3Npb25faWQGOgZFVEkiJWRjYzc5MmM1MTBiMDMzYTUzNTZjNzA4NjBhNWRjZjliBjsAVEkiEF9jc3JmX3Rva2VuBjsARkkiMUp6S2tXT3g5a0FCT01ndzlmWWZqRVJNek1WanRuUDBCbTJUN21GMTBKd3M9BjsARg%3D%3D--2a69429cb2115c6a0cc9a86e0ebe2800c0d471b3',
'Host': 'www.xicidaili.com',
'Referer': 'http://www.xicidaili.com/nn/3',
'Upgrade-Insecure-Requests': '1',
}
html = get_page(start_url, options=headers)
if html:
find_trs = re.compile('<tr class.*?>(.*?)</tr>', re.S)
trs = find_trs.findall(html)
for tr in trs:
find_ip = re.compile('<td>(\d+\.\d+\.\d+\.\d+)</td>')
re_ip_address = find_ip.findall(tr)
find_port = re.compile('<td>(\d+)</td>')
re_port = find_port.findall(tr)
for address, port in zip(re_ip_address, re_port):
address_port = address + ':' + port
yield address_port.replace(' ', '')
def crawl_ip3366(self):
for i in range(1, 4):
start_url = 'http://www.ip3366.net/?stype=1&page={}'.format(i)
html = get_page(start_url)
if html:
find_tr = re.compile('<tr>(.*?)</tr>', re.S)
trs = find_tr.findall(html)
for s in range(1, len(trs)):
find_ip = re.compile('<td>(\d+\.\d+\.\d+\.\d+)</td>')
re_ip_address = find_ip.findall(trs[s])
find_port = re.compile('<td>(\d+)</td>')
re_port = find_port.findall(trs[s])
for address, port in zip(re_ip_address, re_port):
address_port = address + ':' + port
yield address_port.replace(' ', '')
def crawl_iphai(self):
start_url = 'http://www.iphai.com/'
html = get_page(start_url)
if html:
find_tr = re.compile('<tr>(.*?)</tr>', re.S)
trs = find_tr.findall(html)
for s in range(1, len(trs)):
find_ip = re.compile('<td>\s+(\d+\.\d+\.\d+\.\d+)\s+</td>', re.S)
re_ip_address = find_ip.findall(trs[s])
find_port = re.compile('<td>\s+(\d+)\s+</td>', re.S)
re_port = find_port.findall(trs[s])
for address, port in zip(re_ip_address, re_port):
address_port = address + ':' + port
yield address_port.replace(' ', '')
def crawl_data5u(self):
start_url = 'http://www.data5u.com/free/gngn/index.shtml'
headers = {
'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8',
'Accept-Encoding': 'gzip, deflate',
'Accept-Language': 'en-US,en;q=0.9,zh-CN;q=0.8,zh;q=0.7',
'Cache-Control': 'max-age=0',
'Connection': 'keep-alive',
'Cookie': 'JSESSIONID=47AA0C887112A2D83EE040405F837A86',
'Host': 'www.data5u.com',
'Referer': 'http://www.data5u.com/free/index.shtml',
'Upgrade-Insecure-Requests': '1',
'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.108 Safari/537.36',
}
html = get_page(start_url, options=headers)
if html:
ip_address = re.compile('<span><li>(\d+\.\d+\.\d+\.\d+)</li>.*?<li class=\"port.*?>(\d+)</li>', re.S)
re_ip_address = ip_address.findall(html)
for address, port in re_ip_address:
result = address + ':' + port
yield result.replace(' ', '')
class Getter():
def __init__(self):
self.crawler = Crawler()
def run(self):
print('获取器开始执行')
for callback_label in range(self.crawler.__CrawlFuncCount__):
print(callback_label)
callback = self.crawler.__CrawlFunc__[callback_label]
print(callback)
# # 获取代理
# proxies = self.crawler.get_proxies(callback)
# sys.stdout.flush()
# for proxy in proxies:
# self.redis.add(proxy)
if __name__ == '__main__':
get = Getter()
get.run()测试结果
/home/baixiaoxu/PycharmProjects/pytthon-tt/venv/bin/python /home/baixiaoxu/PycharmProjects/pytthon-tt/proxypool/test.py 打印k __module__ 打印v __main__ 打印k __qualname__ 打印v Crawler 打印k get_proxies 打印v <function Crawler.get_proxies at 0x7f905ca5a598> 打印k crawl_daili66 打印v <function Crawler.crawl_daili66 at 0x7f905ca5a620> 打印k crawl_ip3366 打印v <function Crawler.crawl_ip3366 at 0x7f905ca5a840> 打印k crawl_kuaidaili 打印v <function Crawler.crawl_kuaidaili at 0x7f905ca5a730> 打印k crawl_xicidaili 打印v <function Crawler.crawl_xicidaili at 0x7f905ca5a7b8> 打印k crawl_iphai 打印v <function Crawler.crawl_iphai at 0x7f905ca5a6a8> 打印k crawl_data5u 打印v <function Crawler.crawl_data5u at 0x7f905ca5a8c8> 打印k __CrawlFunc__ 打印v ['crawl_daili66', 'crawl_ip3366', 'crawl_kuaidaili', 'crawl_xicidaili', 'crawl_iphai', 'crawl_data5u'] 获取器开始执行 0 crawl_daili66 1 crawl_ip3366 2 crawl_kuaidaili 3 crawl_xicidaili 4 crawl_iphai 5 crawl_data5u 进程完成，退出码 0
以上是“Python3中元类属性怎么用”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注亿速云行业资讯频道！
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