RobotParser引发SSL证书验证失败异常
问题描述：
我正在Python 2.7中编写一个简单的webcrawler，并且在尝试从HTTPS网站检索robots.txt文件时正在获取SSL证书验证失败异常。RobotParser引发SSL证书验证失败异常
下面是相关代码：
def getHTMLpage(pagelink, currenttime):
"Downloads HTML page from server"
#init
#parse URL and get domain name
o = urlparse.urlparse(pagelink,"http")
if o.netloc == "":
netloc = re.search(r"[^/]+\.[^/]+\.[^/]+", o.path)
if netloc:
domainname="http://"+netloc.group(0)+"/"
else:
domainname=o.scheme+"://"+o.netloc+"/"
if o.netloc != "" and o.netloc != None and o.scheme != "mailto": #if netloc isn't empty and it's not a mailto link
link=domainname+o.path[1:]+o.params+"?"+o.query+"#"+o.fragment
if not (robotfiledictionary.get(domainname)): #if robot file for domainname was not downloaded
robotfiledictionary[domainname] = robotparser.RobotFileParser() #initialize robots.txt parser
robotfiledictionary[domainname].set_url(domainname+"robots.txt") #set url for robots.txt
print " Robots.txt for %s initial download" % str(domainname)
robotfiledictionary[domainname].read() #download/read robots.txt
elif (robotfiledictionary.get(domainname)): #if robot file for domainname was already downloaded
if (currenttime - robotfiledictionary[domainname].mtime()) > 3600: #if robot file is older than 1 hour
robotfiledictionary[domainname].read() #download/read robots.txt
print " Robots.txt for %s downloaded" % str(domainname)
robotfiledictionary[domainname].modified() #update time
if robotfiledictionary[domainname].can_fetch("WebCrawlerUserAgent", link): #if access is allowed...
#fetch page
print link
page = requests.get(link, verify=False)
return page.text()
else: #otherwise, report
print " URL disallowed due to robots.txt from %s" % str(domainname)
return "URL disallowed due to robots.txt"
else: #if netloc was empty, URL wasn't parsed. report
print "URL not parsed: %s" % str(pagelink)
return "URL not parsed"
而这里的，我发现了异常：
Robots.txt for https://ehi-siegel.de/ initial download
Traceback (most recent call last):
File "C:\webcrawler.py", line 561, in <module>
HTMLpage = getHTMLpage(link, loopstarttime)
File "C:\webcrawler.py", line 122, in getHTMLpage
robotfiledictionary[domainname].read() #download/read robots.txt
File "C:\Python27\lib\robotparser.py", line 58, in read
f = opener.open(self.url)
File "C:\Python27\lib\urllib.py", line 213, in open
return getattr(self, name)(url)
File "C:\Python27\lib\urllib.py", line 443, in open_https
h.endheaders(data)
File "C:\Python27\lib\httplib.py", line 1053, in endheaders
self._send_output(message_body)
File "C:\Python27\lib\httplib.py", line 897, in _send_output
self.send(msg)
File "C:\Python27\lib\httplib.py", line 859, in send
self.connect()
File "C:\Python27\lib\httplib.py", line 1278, in connect
server_hostname=server_hostname)
File "C:\Python27\lib\ssl.py", line 353, in wrap_socket
_context=self)
File "C:\Python27\lib\ssl.py", line 601, in __init__
self.do_handshake()
File "C:\Python27\lib\ssl.py", line 830, in do_handshake
self._sslobj.do_handshake()
IOError: [Errno socket error] [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:590)
正如你所看到的，我已经改变了代码在结束检索页面忽略SSL证书（我知道这是在生产中皱起眉头，但我想测试它），但现在似乎robotparser.read()函数未通过SSL验证。我已经看到我可以手动下载证书并指出该方向以验证SSL证书，但理想情况下，我想让我的程序“现成”，因为我本人不会成为一个使用它。有谁知道该怎么做？
编辑：我进入了robotparser.py。我加
import requests
，改变线58
f = requests.get(self.url, verify=False)
，这似乎已经解决了。这仍然不是很理想，所以我仍然乐于接受关于如何做的建议。
答
我自己找到了解决方案。使用urllib3的请求功能，我能够认证所有网站并继续访问它们。
我仍然必须编辑robotparser.py文件。这是我加入到开头：
import urllib3
import urllib3.contrib.pyopenssl
import certifi
urllib3.contrib.pyopenssl.inject_into_urllib3()
http = urllib3.PoolManager(cert_reqs="CERT_REQUIRED", ca_certs=certifi.where())
这是读的定义（个体经营）：
def read(self):
"""Reads the robots.txt URL and feeds it to the parser."""
opener = URLopener()
f = http.request('GET', self.url)
lines = [line.strip() for line in f.data]
f.close()
self.errcode = opener.errcode
if self.errcode in (401, 403):
self.disallow_all = True
elif self.errcode >= 400 and self.errcode < 500:
self.allow_all = True
elif self.errcode == 200 and lines:
self.parse(lines)
我也用同样的过程中得到我的程序的功能，实际的页面请求：
def getHTMLpage(pagelink, currenttime):
"Downloads HTML page from server"
#init
#parse URL and get domain name
o = urlparse.urlparse(pagelink,u"http")
if o.netloc == u"":
netloc = re.search(ur"[^/]+\.[^/]+\.[^/]+", o.path)
if netloc:
domainname=u"http://"+netloc.group(0)+u"/"
else:
domainname=o.scheme+u"://"+o.netloc+u"/"
if o.netloc != u"" and o.netloc != None and o.scheme != u"mailto": #if netloc isn't empty and it's not a mailto link
link=domainname+o.path[1:]+o.params+u"?"+o.query+u"#"+o.fragment
if not (robotfiledictionary.get(domainname)): #if robot file for domainname was not downloaded
robotfiledictionary[domainname] = robotparser.RobotFileParser() #initialize robots.txt parser
robotfiledictionary[domainname].set_url(domainname+u"robots.txt") #set url for robots.txt
print u" Robots.txt for %s initial download" % str(domainname)
robotfiledictionary[domainname].read() #download/read robots.txt
elif (robotfiledictionary.get(domainname)): #if robot file for domainname was already downloaded
if (currenttime - robotfiledictionary[domainname].mtime()) > 3600: #if robot file is older than 1 hour
robotfiledictionary[domainname].read() #download/read robots.txt
print u" Robots.txt for %s downloaded" % str(domainname)
robotfiledictionary[domainname].modified() #update time
if robotfiledictionary[domainname].can_fetch("WebCrawlerUserAgent", link.encode('utf-8')): #if access is allowed...
#fetch page
if domainname == u"https://www.otto.de/" or domainname == u"http://www.otto.de":
driver.get(link.encode('utf-8'))
time.sleep(5)
page=driver.page_source
return page
else:
page = http.request('GET',link.encode('utf-8'))
return page.data.decode('UTF-8','ignore')
else: #otherwise, report
print u" URL disallowed due to robots.txt from %s" % str(domainname)
return u"URL disallowed due to robots.txt"
else: #if netloc was empty, URL wasn't parsed. report
print u"URL not parsed: %s" % str(pagelink)
return u"URL not parsed"
您还会注意到我改变了我的程序中使用严格UTF-8，但这是无关的。