Python3中元类属性怎么用

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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  : testimport jsonimport refrom pyquery import PyQuery as pqclass 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('\s*(.*?)\s*(.*?)')      # \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('(.*?)')        re_ip_address = ip_address.findall(html)        port = re.compile('(.*?)')        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('(.*?)', re.S)        trs = find_trs.findall(html)        for tr in trs:          find_ip = re.compile('(\d+\.\d+\.\d+\.\d+)')          re_ip_address = find_ip.findall(tr)          find_port = re.compile('(\d+)')          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('(.*?)', re.S)        trs = find_tr.findall(html)        for s in range(1, len(trs)):          find_ip = re.compile('(\d+\.\d+\.\d+\.\d+)')          re_ip_address = find_ip.findall(trs[s])          find_port = re.compile('(\d+)')          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('(.*?)', re.S)      trs = find_tr.findall(html)      for s in range(1, len(trs)):        find_ip = re.compile('\s+(\d+\.\d+\.\d+\.\d+)\s+', re.S)        re_ip_address = find_ip.findall(trs[s])        find_port = re.compile('\s+(\d+)\s+', 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('
(\d+\.\d+\.\d+\.\d+)
.*?
(\d+)
', 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vCrawler打印kget_proxies打印v打印kcrawl_daili66打印v打印kcrawl_ip3366打印v打印kcrawl_kuaidaili打印v打印kcrawl_xicidaili打印v打印kcrawl_iphai打印v打印kcrawl_data5u打印v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0crawl_daili661crawl_ip33662crawl_kuaidaili3crawl_xicidaili4crawl_iphai5crawl_data5u进程完成，退出码 0

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