FM / cachecontrol

/usr/lib/python3.6/site-packages/pip/_vendor/cachecontrol/

/usr/lib/python3.6/site-packages/pip/_vendor/cachecontrol

Name	Size	Mode	Actions
caches/	-	0755	rm
__pycache__/	-	0755	rm
adapter.py	4608	0644	edit dl rm
cache.py	790	0644	edit dl rm
compat.py	380	0644	edit dl rm
controller.py	13024	0644	edit dl rm
filewrapper.py	2531	0644	edit dl rm
heuristics.py	4141	0644	edit dl rm
serialize.py	6536	0644	edit dl rm
wrapper.py	498	0644	edit dl rm
_cmd.py	1320	0644	edit dl rm
__init__.py	302	0644	edit dl rm

Edit: /usr/lib/python3.6/site-packages/pip/_vendor/cachecontrol/heuristics.py (4141B)

import calendar
import time

from email.utils import formatdate, parsedate, parsedate_tz

from datetime import datetime, timedelta

TIME_FMT = "%a, %d %b %Y %H:%M:%S GMT"

def expire_after(delta, date=None):
    date = date or datetime.now()
    return date + delta

def datetime_to_header(dt):
    return formatdate(calendar.timegm(dt.timetuple()))

class BaseHeuristic(object):

def warning(self, response):
        """
        Return a valid 1xx warning header value describing the cache
        adjustments.

The response is provided too allow warnings like 113
        http://tools.ietf.org/html/rfc7234#section-5.5.4 where we need
        to explicitly say response is over 24 hours old.
        """
        return '110 - "Response is Stale"'

def update_headers(self, response):
        """Update the response headers with any new headers.

NOTE: This SHOULD always include some Warning header to
              signify that the response was cached by the client, not
              by way of the provided headers.
        """
        return {}

def apply(self, response):
        updated_headers = self.update_headers(response)

if updated_headers:
            response.headers.update(updated_headers)
            warning_header_value = self.warning(response)
            if warning_header_value is not None:
                response.headers.update({'Warning': warning_header_value})

return response

class OneDayCache(BaseHeuristic):
    """
    Cache the response by providing an expires 1 day in the
    future.
    """
    def update_headers(self, response):
        headers = {}

if 'expires' not in response.headers:
            date = parsedate(response.headers['date'])
            expires = expire_after(timedelta(days=1),
                                   date=datetime(*date[:6]))
            headers['expires'] = datetime_to_header(expires)
            headers['cache-control'] = 'public'
        return headers

class ExpiresAfter(BaseHeuristic):
    """
    Cache **all** requests for a defined time period.
    """

def __init__(self, **kw):
        self.delta = timedelta(**kw)

def update_headers(self, response):
        expires = expire_after(self.delta)
        return {
            'expires': datetime_to_header(expires),
            'cache-control': 'public',
        }

def warning(self, response):
        tmpl = '110 - Automatically cached for %s. Response might be stale'
        return tmpl % self.delta

class LastModified(BaseHeuristic):
    """
    If there is no Expires header already, fall back on Last-Modified
    using the heuristic from
    http://tools.ietf.org/html/rfc7234#section-4.2.2
    to calculate a reasonable value.

Firefox also does something like this per
    https://developer.mozilla.org/en-US/docs/Web/HTTP/Caching_FAQ
    http://lxr.mozilla.org/mozilla-release/source/netwerk/protocol/http/nsHttpResponseHead.cpp#397
    Unlike mozilla we limit this to 24-hr.
    """
    cacheable_by_default_statuses = set([
        200, 203, 204, 206, 300, 301, 404, 405, 410, 414, 501
    ])

def update_headers(self, resp):
        headers = resp.headers

if 'expires' in headers:
            return {}

if 'cache-control' in headers and headers['cache-control'] != 'public':
            return {}

if resp.status not in self.cacheable_by_default_statuses:
            return {}

if 'date' not in headers or 'last-modified' not in headers:
            return {}

date = calendar.timegm(parsedate_tz(headers['date']))
        last_modified = parsedate(headers['last-modified'])
        if date is None or last_modified is None:
            return {}

now = time.time()
        current_age = max(0, now - date)
        delta = date - calendar.timegm(last_modified)
        freshness_lifetime = max(0, min(delta / 10, 24 * 3600))
        if freshness_lifetime <= current_age:
            return {}

expires = date + freshness_lifetime
        return {'expires': time.strftime(TIME_FMT, time.gmtime(expires))}

def warning(self, resp):
        return None

cmd: