urllib2.Request 检查 URL 是否可达

Question

所以我有以下代码来验证某些 url 是否正确，我只需要 200 响应所以我制作了一个脚本工作正常但它太慢了（：

import urllib2
import string
def my_range(start, end, step):
    while start <= end:
        yield start
        start += step
url = 'http://exemple.com/test/'
y = 1
for x in my_range(1, 5, 1):
 y =y+1 
 url+=str(y)
 print url 
 req = urllib2.Request(url)
 try:
    resp = urllib2.urlopen(req)
 except urllib2.URLError, e:
    if e.code == 404:
        print "404"
    else:
        print "not 404"
 else:
    print "200"
 url = 'http://exemple.com/test/'
body = resp.read()

在此示例中，我假设我的本地主机中有以下目录以及此结果

http://exemple.com/test/2
200
http://exemple.com/test/3
200
http://exemple.com/test/4
404
http://exemple.com/test/5
404
http://exemple.com/test/6
404

所以我搜索了如何更快地做到这一点，我发现了这段代码：

import urllib2
request = urllib2.Request('http://www.google.com/')
response = urllib2.urlopen(request)
if response.getcode() == 200:
   print "200"    

它似乎更快但是当我用 404 测试它时 (http://www.google.com/111) 它给了我这个结果：

Traceback (most recent call last):
  File "C:\Python27\res.py", line 3, in <module>
    response = urllib2.urlopen(request)
  File "C:\Python27\lib\urllib2.py", line 126, in urlopen
    return _opener.open(url, data, timeout)
  File "C:\Python27\lib\urllib2.py", line 400, in open
    response = meth(req, response)
  File "C:\Python27\lib\urllib2.py", line 513, in http_response
    'http', request, response, code, msg, hdrs)
  File "C:\Python27\lib\urllib2.py", line 438, in error
    return self._call_chain(*args)
  File "C:\Python27\lib\urllib2.py", line 372, in _call_chain
    result = func(*args)
  File "C:\Python27\lib\urllib2.py", line 521, in http_error_default
    raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
urllib2.HTTPError: HTTP Error 404: Not Found

有什么想法吗？ 非常感谢您的帮助:)

Answer 1

HTTPError 被定义为一系列异常，因此您可以在以下情况下使用 Try/Except：

import urllib2
request = urllib2.Request('http://www.google.com/')
try:
    response = urllib.urlopen(request)
    # do stuff..
except urllib2.HTTPError: # 404, 500, etc..
    pass

您还可以为 urllib2.URLError 添加进一步的 except 子句，该子句涵盖其他（非 HTTP）错误，例如超时。