# Copyright (c) 2006-2007 Thomas Lotze
# See also LICENSE.txt
import datetime
import md5
import codecs
import ophelia.request
import ophelia.util
RFC2822_FORMAT = "%a, %d %b %Y %H:%M:%S GMT"
HEX_ENCODER = codecs.getencoder("hex_codec")
class MetaData(object):
"""Stores, calculates and formats metadata such as dates or digests.
"""
def __init__(self):
self.request = ophelia.request.get_request()
self._date = datetime.datetime.min
def bump_date(self, *args):
"""Store the maximum of the given date and that stored before.
*args: datetime.datetime arguments
returns nothing
"""
date = datetime.datetime(*args)
self._date = max(self._date, date)
def date(self, format=RFC2822_FORMAT):
"""Format the stored date, defaults to RFC 2822 compliant format.
format: str, format str
returns str
"""
return ophelia.util.strftime(format, self._date)
def expires(self, *args):
"""Calulate a date relative to now, format by RFC 2822.
*args: datetime.timedelta arguments
returns str
"""
exp_date = datetime.datetime.now() + datetime.timedelta(*args)
return exp_date.strftime(RFC2822_FORMAT)
def etag(self):
"""Calculate an ETag for the page.
returns str
"""
if self.request.content is None:
raise RuntimeError(
"Can't compute an Etag before content has been built.")
obj = md5.new()
obj.update(self.request.content)
return HEX_ENCODER(obj.digest())[0]
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