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#!/usr/bin/env python
"""Module that checks if there is an updated version of a package available."""
from __future__ import print_function
import json
import os
import pickle
import platform
import re
import requests
import sys
import time
from datetime import datetime
from functools import wraps
from requests.status_codes import codes
from tempfile import gettempdir
__version__ = '0.16'
datetime.strptime('', '')
def cache_results(function):
"""Return decorated function that caches the results."""
def save_to_permacache():
"""Save the in-memory cache data to the permacache.
There is a race condition here between two processes updating at the
same time. It's perfectly acceptable to lose and/or corrupt the
permacache information as each process's in-memory cache will remain
with open(filename, 'wb') as fp:
pickle.dump(cache, fp, pickle.HIGHEST_PROTOCOL)
except IOError:
pass # Ignore permacache saving exceptions
def update_from_permacache():
"""Attempt to update newer items from the permacache."""
with open(filename, 'rb') as fp:
permacache = pickle.load(fp)
except Exception: # TODO: Handle specific exceptions
return # It's okay if it cannot load
for key, value in permacache.items():
if key not in cache or value[0] > cache[key][0]:
cache[key] = value
cache = {}
cache_expire_time = 3600
filename = os.path.join(gettempdir(), 'update_checker_cache.pkl')
except NotImplementedError:
filename = None
def wrapped(obj, package_name, package_version, **extra_data):
"""Return cached results if available."""
now = time.time()
key = (package_name, package_version)
if not obj.bypass_cache and key in cache: # Check the in-memory cache
cache_time, retval = cache[key]
if now - cache_time < cache_expire_time:
return retval
retval = function(obj, package_name, package_version, **extra_data)
cache[key] = now, retval
if filename:
return retval
return wrapped
# This class must be defined before UpdateChecker in order to unpickle objects
# of this type
class UpdateResult(object):
"""Contains the information for a package that has an update."""
def __init__(self, package, running, available, release_date):
"""Initialize an UpdateResult instance."""
self.available_version = available
self.package_name = package
self.running_version = running
if release_date:
self.release_date = datetime.strptime(release_date,
self.release_date = None
def __str__(self):
"""Return a printable UpdateResult string."""
retval = ('Version {0} of {1} is outdated. Version {2} '
.format(self.running_version, self.package_name,
if self.release_date:
retval += 'was released {0}.'.format(
retval += 'is available.'
return retval
class UpdateChecker(object):
"""A class to check for package updates."""
def __init__(self, url=None):
"""Store the URL to use for checking."""
self.bypass_cache = False
self.url = url if url \
else ''
def check(self, package_name, package_version, **extra_data):
"""Return a UpdateResult object if there is a newer version."""
data = extra_data
data['package_name'] = package_name
data['package_version'] = package_version
data['python_version'] = sys.version.split()[0]
data['platform'] = platform.platform(True) or 'Unspecified'
headers = {'connection': 'close',
'content-type': 'application/json'}
response = requests.put(self.url, json.dumps(data), timeout=1,
if response.status_code == codes.UNPROCESSABLE_ENTITY:
return 'update_checker does not support {!r}'.format(
data = response.json()
except (requests.exceptions.RequestException, ValueError):
return None
if not data or not data.get('success') \
or (parse_version(package_version) >=
return None
return UpdateResult(package_name, running=package_version,
def pretty_date(the_datetime):
"""Attempt to return a human-readable time delta string."""
# Source modified from
diff = datetime.utcnow() - the_datetime
if diff.days > 7 or diff.days < 0:
return the_datetime.strftime('%A %B %d, %Y')
elif diff.days == 1:
return '1 day ago'
elif diff.days > 1:
return '{0} days ago'.format(diff.days)
elif diff.seconds <= 1:
return 'just now'
elif diff.seconds < 60:
return '{0} seconds ago'.format(diff.seconds)
elif diff.seconds < 120:
return '1 minute ago'
elif diff.seconds < 3600:
return '{0} minutes ago'.format(int(round(diff.seconds / 60)))
elif diff.seconds < 7200:
return '1 hour ago'
return '{0} hours ago'.format(int(round(diff.seconds / 3600)))
def update_check(package_name, package_version, bypass_cache=False, url=None,
"""Convenience method that outputs to stdout if an update is available."""
checker = UpdateChecker(url)
checker.bypass_cache = bypass_cache
result = checker.check(package_name, package_version, **extra_data)
if result:
# The following section of code is taken from setuptools (PSF
# license). Unfortunately importing pkg_resources to directly use the
# parse_version function results in some undesired side effects.
component_re = re.compile(r'(\d+ | [a-z]+ | \.| -)', re.VERBOSE)
replace = {'pre': 'c', 'preview': 'c', '-': 'final-', 'rc': 'c',
'dev': '@'}.get
def _parse_version_parts(s):
for part in component_re.split(s):
part = replace(part, part)
if not part or part == '.':
if part[:1] in '0123456789':
yield part.zfill(8) # pad for numeric comparison
yield '*'+part
yield '*final' # ensure that alpha/beta/candidate are before final
def parse_version(s):
"""Convert a version string to a chronologically-sortable key.
This is a rough cross between distutils' StrictVersion and LooseVersion;
if you give it versions that would work with StrictVersion, then it behaves
the same; otherwise it acts like a slightly-smarter LooseVersion. It is
*possible* to create pathological version coding schemes that will fool
this parser, but they should be very rare in practice.
The returned value will be a tuple of strings. Numeric portions of the
version are padded to 8 digits so they will compare numerically, but
without relying on how numbers compare relative to strings. Dots are
dropped, but dashes are retained. Trailing zeros between alpha segments
or dashes are suppressed, so that e.g. "2.4.0" is considered the same as
"2.4". Alphanumeric parts are lower-cased.
The algorithm assumes that strings like "-" and any alpha string that
alphabetically follows "final" represents a "patch level". So, "2.4-1"
is assumed to be a branch or patch of "2.4", and therefore "2.4.1" is
considered newer than "2.4-1", which in turn is newer than "2.4".
Strings like "a", "b", "c", "alpha", "beta", "candidate" and so on (that
come before "final" alphabetically) are assumed to be pre-release versions,
so that the version "2.4" is considered newer than "2.4a1".
Finally, to handle miscellaneous cases, the strings "pre", "preview", and
"rc" are treated as if they were "c", i.e. as though they were release
candidates, and therefore are not as new as a version string that does not
contain them, and "dev" is replaced with an '@' so that it sorts lower than
than any other pre-release tag.
parts = []
for part in _parse_version_parts(s.lower()):
if part.startswith('*'):
if part < '*final': # remove '-' before a prerelease tag
while parts and parts[-1] == '*final-':
# remove trailing zeros from each series of numeric parts
while parts and parts[-1] == '00000000':
return tuple(parts)