How do I parse an HTTP date-string in Python?

Is there an easy way to parse HTTP date-strings in Python? According to the standard, there are several ways to format HTTP date strings; the method should be able to handle this.

In other words, I want to convert a string like "Wed, 23 Sep 2009 22:15:29 GMT" to a python time-structure.

回答1:

>>> import email.utils as eut
>>> eut.parsedate('Wed, 23 Sep 2009 22:15:29 GMT')
(2009, 9, 23, 22, 15, 29, 0, 1, -1)

If you want a datetime.datetime object, you can do:

def my_parsedate(text):
    return datetime.datetime(*eut.parsedate(text)[:6])

回答2:

>>> import datetime
>>> datetime.datetime.strptime('Wed, 23 Sep 2009 22:15:29 GMT', '%a, %d %b %Y %H:%M:%S GMT')
datetime.datetime(2009, 9, 23, 22, 15, 29)

回答3:

httplib.HTTPMessage(filehandle).getdate(headername)
httplib.HTTPMessage(filehandle).getdate_tz(headername)
mimetools.Message(filehandle).getdate()
rfc822.parsedate(datestr)
rfc822.parsedate_tz(datestr)

if you have a raw data stream, you can build an HTTPMessage or a mimetools.Message from it. it may offer additional help while querying the response object for infos
if you are using urllib2, you already have an HTTPMessage object hidden in the filehandler returned by urlopen
it can probably parse many date formats
httplib is in the core

NOTE:

had a look at implementation, HTTPMessage inherits from mimetools.Message which inherits from rfc822.Message. two floating defs are of your interest maybe, parsedate and parsedate_tz (in the latter)
parsedate(_tz) from email.utils has a different implementation, although it looks kind of the same.

you can do this, if you only have that piece of string and you want to parse it:

>>> from rfc822 import parsedate, parsedate_tz
>>> parsedate('Wed, 23 Sep 2009 22:15:29 GMT')
(2009, 9, 23, 22, 15, 29, 0, 1, 0)
>>>

but let me exemplify through mime messages:

import mimetools
import StringIO
message = mimetools.Message(
    StringIO.StringIO('Date:Wed, 23 Sep 2009 22:15:29 GMT\r\n\r\n'))
>>> m
<mimetools.Message instance at 0x7fc259146710>
>>> m.getdate('Date')
(2009, 9, 23, 22, 15, 29, 0, 1, 0)

or via http messages (responses)

>>> from httplib import HTTPMessage
>>> from StringIO import StringIO
>>> http_response = HTTPMessage(StringIO('Date:Wed, 23 Sep 2009 22:15:29 GMT\r\n\r\n'))
>>> #http_response can be grabbed via urllib2.urlopen(url).info(), right?
>>> http_response.getdate('Date')
(2009, 9, 23, 22, 15, 29, 0, 1, 0)

right?

>>> import urllib2
>>> urllib2.urlopen('https://fw.io/').info().getdate('Date')
(2014, 2, 19, 18, 53, 26, 0, 1, 0)

there, now we now more about date formats, mime messages, mime tools and their pythonic implementation ;-)

whatever the case, looks better than using email.utils for parsing http headers.