关于html：Python 3 urllib HTTP错误412：前置条件失败

Python 3 urllib HTTP Error 412: Precondition Failed

我正在尝试解析网站的HTML数据。我写了这段代码：

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import urllib.request

def parse(url):
response = urllib.request.urlopen(url)
html = response.read()
strHTML = html.decode()
return strHTML

website ="http://www.manarat.ac.bd/"
string = parse(website)

但它显示此错误：

Traceback (most recent call last):
File"C:\Users\pupewekate\Videos
AW\2.py", line 11, in
string = parse(website)
File"C:\Users\pupewekate\Videos
AW\2.py", line 5, in parse
response = urllib.request.urlopen(url)
File
"C:\Users\pupewekate\AppData\Local\Programs\Python\Python36-32\lib\urllib
equest.py",
line 223, in urlopen return opener.open(url, data, timeout)
File
"C:\Users\pupewekate\AppData\Local\Programs\Python\Python36-32\lib\urllib
equest.py",
line 532, in open response = meth(req, response)
File
"C:\Users\pupewekate\AppData\Local\Programs\Python\Python36-32\lib\urllib
equest.py",
line 642, in http_response 'http', request, response, code, msg,
hdrs)
File
"C:\Users\pupewekate\AppData\Local\Programs\Python\Python36-32\lib\urllib
equest.py",
line 570, in error return > self._call_chain(*args)
File
"C:\Users\pupewekate\AppData\Local\Programs\Python\Python36-32\lib\urllib
equest.py",
line 504, in _call_chain result = func(*args)
File
"C:\Users\pupewekate\AppData\Local\Programs\Python\Python36-32\lib\urllib
equest.py",
line 650, in http_error_default raise HTTPError(req.full_url, code,
msg, hdrs, fp) urllib.error.HTTPError: HTTP Error 412: Precondition
Failed

有解决方案吗

您可以使用请求模块，因为它更容易实现，否则如果您决定使用urllib，您可以使用：

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import urllib

def parse(url):
headers = {'User-Agent': 'Mozilla/5.0 (Windows NT 6.3;Win64;x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36'}
response = urllib.request.urlopen(url,headers=headers)
print response

website ="http://www.manarat.ac.bd/"
string = parse(website)

该网站检查用户代理标头。如果它无法识别其值，则返回状态代码412：

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import requests

print(requests.get('http://www.manarat.ac.bd/'))
# <Response [412]>

print(requests.get('http://www.manarat.ac.bd/', headers={'User-Agent': 'Chrome'}))
# <Response [200]>

有关如何在urlib中设置用户代理，请参阅此答案。