Python httplib2处理异常 [英] Python httplib2 Handling Exceptions

问题描述

我有这个非常简单的代码来检查网站是否正常运行.

I have this very simple code to check if a site is up or down.

import httplib2
h = httplib2.Http()
response, content = h.request("http://www.folksdhhkjd.com")
if response.status == 200:
    print "Site is Up"
else:
    print "Site is down"

当我输入有效的URL时，它会正确打印"Site is Up"，因为状态为200，如预期的那样.但是，当我输入无效的URL时，是否应该不打印网站已关闭?相反，它会打印出类似这样的异常

When I enter a valid URL then it properly prints Site is Up because the status is 200 as expected. But, when I enter an invalid URL, should it not print Site is down? Instead it prints an exception something like this

Traceback (most recent call last):
  File "C:\Documents and Settings\kripya\Desktop\1.py", line 3, in <module>
    response, content = h.request("http://www.folksdhhkjd.com")
  File "C:\Python27\lib\site-packages\httplib2\__init__.py", line 1436, in request
    (response, content) = self._request(conn, authority, uri, request_uri, method, body, headers, redirections, cachekey)
  File "C:\Python27\lib\site-packages\httplib2\__init__.py", line 1188, in _request
    (response, content) = self._conn_request(conn, request_uri, method, body, headers)
  File "C:\Python27\lib\site-packages\httplib2\__init__.py", line 1129, in _conn_request
    raise ServerNotFoundError("Unable to find the server at %s" % conn.host)
ServerNotFoundError: Unable to find the server at www.folksdhhkjd.com

如何覆盖此异常并打印我的自定义定义的站点已关闭"消息?有任何指导吗?

How can I override this exception and print my custom defined "Site is down" message? Any guidance, please?

编辑

还有一个问题...使用

Also one more question... what is the difference between using

h = httplib2.Http('.cache')   

和

h = httplib2.Http()   

推荐答案

try:
    response, content = h.request("http://www.folksdhhkjd.com")
    if response.status==200:
        print "Site is Up"
except httplib2.ServerNotFoundError:
    print "Site is Down"

您的代码存在的问题是，如果主机不响应，则请求不会返回任何状态代码，因此库将引发错误(我认为这是库本身的特殊性，它会执行某些操作尝试提出请求之前先进行DNS解析.

The issue with your code is that if the host doesn't respond, the request doesn't return ANY status code, and so the library throws an error (I think it's a peculiarity of the library itself, doing some sort of DNS resolution before trying to make the request).

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