我试图实现一个简单的网络爬虫,我已经写了一个简单的代码开始:有两个模块fetcher.py和crawler.py。
fetcher.py:
import urllib2
import re
def fetcher(s):
"fetch a web page from a url"
try:
req = urllib2.Request(s)
urlResponse = urllib2.urlopen(req).read()
except urllib2.URLError as e:
print e.reason
return
p,q = s.split("//")
d = q.split("/")
fdes = open(d[0],"w+")
fdes.write(str(urlResponse))
fdes.seek(0)
return fdes
if __name__ == "__main__":
defaultSeed = "http://www.python.org"
print fetcher(defaultSeed)
爬虫.py:
from bs4 import BeautifulSoup
import re
from fetchpage import fetcher
usedLinks = open("Used","a+")
newLinks = open("New","w+")
newLinks.seek(0)
def p(fd,var=0):
soup = BeautifulSoup(fd)
for li in soup.find_all("a",xxx=re.compile("http")):
newLinks.seek(0,2)
newLinks.write(str(li.get("href")).strip("/"))
newLinks.write("\n")
fd.close()
newLinks.seek(var)
link = newLinks.readline().strip("\n")
return str(link)
def crawler(seed,n):
if n == 0:
usedLinks.close()
newLinks.close()
return
else:
usedLinks.write(seed)
usedLinks.write("\n")
fdes = fetcher(seed)
newSeed = p(fdes,newLinks.tell())
crawler(newSeed,n-1)
if __name__ == "__main__":
crawler("http://www.python.org/",7)
问题是,当我运行crawler.py它工作正常的前 4-5 个链接,然后挂起,一分钟后给我以下错误:
[Errno 110] Connection timed out
Traceback (most recent call last):
File "crawler.py", line 37, in <module>
crawler("http://www.python.org/",7)
File "crawler.py", line 34, in crawler
crawler(newSeed,n-1)
File "crawler.py", line 34, in crawler
crawler(newSeed,n-1)
File "crawler.py", line 34, in crawler
crawler(newSeed,n-1)
File "crawler.py", line 34, in crawler
crawler(newSeed,n-1)
File "crawler.py", line 34, in crawler
crawler(newSeed,n-1)
File "crawler.py", line 33, in crawler
newSeed = p(fdes,newLinks.tell())
File "crawler.py", line 11, in p
soup = BeautifulSoup(fd)
File "/usr/lib/python2.7/dist-packages/bs4/__init__.py", line 169, in __init__
self.builder.prepare_markup(markup, from_encoding))
File "/usr/lib/python2.7/dist-packages/bs4/builder/_lxml.py", line 68, in prepare_markup
= UnicodeDammit(markup, try_encodings, is_html=True)
File "/usr/lib/python2.7/dist-packages/bs4/.py", line 191, in __init__
self._detectEncoding(markup, is_html)
File "/usr/lib/python2.7/dist-packages/bs4/.py", line 362, in _detectEncoding
xml_encoding_match = xml_encoding_re.match(xml_data)
TypeError: expected string or buffer
任何人都可以帮助我,我很新的 python,我无法找出为什么它说连接超时一段时间后?
Connection Timeout不是特定于 python 的,它只是意味着您向服务器发出请求,并且服务器在您的应用程序愿意等待的时间内没有响应。
这可能发生的原因很可能是 python.org 可能有一些机制来检测它何时从脚本中获取多个请求,并且可能在 4-5 个请求后完全停止服务页面。
您可以尝试使用代理来避免在如上所述的多个请求中被检测到。您可能希望查看此答案,以了解如何使用代理发送 urllib 请求:How to open website with urllib via Proxy - Python
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