MacOS下使用爬虫发生urllib.error.URLError

urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: self signed certificate in certificate chain (_ssl.c:1045)>

发生了这样的错误，但是在Windows10下就不会发生，查到了一许流星的博客，发现可以这样解决，但是只是解决问题，并没有理解问题发生的原因

在他博客中

可能原因分析：

Python 2.7.9 之后引入了一个新特性
当你urllib.urlopen一个 https 的时候会验证一次 SSL 证书 
当目标使用的是自签名的证书时就会爆出一个 
urllib2.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate 
verify failed 		(_ssl.c:581)> 的错误消息

处理方式如下：

import ssl
 
# This restores the same behavior as before.
context = ssl._create_unverified_context()
response = urllib.request.urlopen("https://no-valid-cert", context=context)

如此这样那我在网上copy的代码(爬去熊猫TV英雄联盟的主播rank)就可以完美运行

import re
from urllib import request
import ssl

context = ssl._create_unverified_context()


class Spider():
    # 匹配所有字符 [\s\S]*? 非贪婪
    url = 'https://www.panda.tv/cate/lol'
    root_pattern = '<div class="video-info">([\w\W]*?)</div>'
    name_pattern = '</i>([\w\W]*?)</span>'
    number_pattern = '<span class="video-number">([\w\W]*?)</span>'

    def __fetch_content(self):

        r = request.urlopen(Spider.url, context=context)
        # 字节码
        htmls = r.read()
        htmls = str(htmls, encoding='utf-8')

        return htmls

    def __analysis(self, htmls):
        root_html = re.findall(Spider.root_pattern, htmls)

        anchors = []
        for html in root_html:
            name = re.findall(Spider.name_pattern, html)
            number = re.findall(Spider.number_pattern, html)
            anchor = {'name': name, 'number': number}
            anchors.append(anchor)
        return anchors

    def __refine(self, anchors):

        # 匿名函数lambda
        l = lambda anchor: {'name': anchor['name'][0].strip(), 'number': anchor['number'][0]}
        return map(l, anchors)

    def __sort(self, anchors):

        # 默认增序
        anchors = sorted(anchors, key=self.__sort_seed, reverse=True)

        return anchors

    def __sort_seed(self, anchor):
        r = re.findall('\d*', anchor['number'])
        number = float(r[0])
        if '万' in anchor['number']:
            number *= 10000

        return number

    def __show(self, anchors):
        for rank in range(0, len(anchors)):
            print('rank' + str(rank + 1) + ':' + anchors[rank]['name'] + ' ' + anchors[rank]['number'])

    def go(self):
        htmls = self.__fetch_content()
        anchors = self.__analysis(htmls)
        anchors = list(self.__refine(anchors))
        anchors = self.__sort(anchors)
        self.__show(anchors)


spider = Spider()
spider.go()

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最后

恭喜IG今天获得S8总冠军