先贴一下原来的代码,是按照书上直接抄下来的
from urllib.robotparser import RobotFileParser
from urllib.request import urlopen
rp = RobotFileParser()
rp.parse(urlopen('http://www.jianshu.com/robots.txt').read().decode('utf-8').split('\n'))
print(rp.can_fetch('*', 'http://www.jianshu.com/p/b67554025d7d'))
print(rp.can_fetch('*', 'http://www.jianshu.com/search?q=python&page=1&type=collections'))
然后就Pycharm就报出了如下错误:
Traceback (most recent call last):
File "E:/PythonProject/PaChong/first.py", line 15, in <module>
rp.parse((urlopen('http://www.jianshu.com/robots.txt').read().decode('utf-8').split('\n')))
File "E:\Python\lib\urllib\request.py", line 222, in urlopen
return opener.open(url, data, timeout)
File "E:\Python\lib\urllib\request.py", line 531, in open
response = meth(req, response)
File "E:\Python\lib\urllib\request.py", line 641, in http_response
'http', request, response, code, msg, hdrs)
File "E:\Python\lib\urllib\request.py", line 563, in error
result = self._call_chain(*args)
File "E:\Python\lib\urllib\request.py", line 503, in _call_chain
result = func(*args)
File "E:\Python\lib\urllib\request.py", line 755, in http_error_302
return self.parent.open(new, timeout=req.timeout)
File "E:\Python\lib\urllib\request.py", line 531, in open
response = meth(req, response)
File "E:\Python\lib\urllib\request.py", line 641, in http_response
'http', request, response, code, msg, hdrs)
File "E:\Python\lib\urllib\request.py", line 569, in error
return self._call_chain(*args)
File "E:\Python\lib\urllib\request.py", line 503, in _call_chain
result = func(*args)
File "E:\Python\lib\urllib\request.py", line 649, in http_error_default
raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 403: Forbidden
直接看最后一行,是HTTP Error 403:Frobidden
经过搜索,出现这个原因是因为用urllib.request.urlopen方式打开一个URL的话,服务器只会收到一个单纯的对于该页面访问的请求,但是服务器并不知道发送这个请求使用的浏览器,操作系统等信息,而缺失这些信息的访问往往都是非正常访问,会被一些网站禁止掉。
那么该如何解决这个问题呢?只需要在请求中加入UserAgent信息就行了
如下
from urllib.robotparser import RobotFileParser
from urllib import request
rp = RobotFileParser()
headers = {
'User-Agent': 'Mozilla/4.0(compatible; MSIE 5.5; Windows NT)'
}
url = 'http://www.jianshu.com/robots.txt'
req = request.Request(url=url, headers=headers)
response = request.urlopen(req)
rp.parse(response.read().decode('utf-8').split('\n'))
print(rp.can_fetch('*', 'http://www.jianshu.com/p/b67554025d7d'))
print(rp.can_fetch('*', 'http://www.jianshu.com/search?q=python&page=1&type=collections'))
这样问题就完美解决了
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