##############################################################################
#
# Copyright (c) 2009 Zope Corporation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Buildout download infrastructure"""
try:
from hashlib import md5
except ImportError:
from md5 import new as md5
from zc.buildout.easy_install import realpath
import logging
import os
import os.path
import re
import shutil
import tempfile
import urllib
import urlparse
import zc.buildout
class URLOpener(urllib.FancyURLopener):
http_error_default = urllib.URLopener.http_error_default
class ChecksumError(zc.buildout.UserError):
pass
url_opener = URLOpener()
class Download(object):
"""Configurable download utility.
Handles the download cache and offline mode.
Download(options=None, cache=None, namespace=None, hash_name=False)
options: mapping of buildout options (e.g. a ``buildout`` config section)
cache: path to the download cache (excluding namespaces)
namespace: namespace directory to use inside the cache
hash_name: whether to use a hash of the URL as cache file name
logger: an optional logger to receive download-related log messages
"""
def __init__(self, options={}, cache=-1, namespace=None,
offline=-1, fallback=False, hash_name=False, logger=None):
self.directory = options.get('directory', '')
self.cache = cache
if cache == -1:
self.cache = options.get('download-cache')
self.namespace = namespace
self.offline = offline
if offline == -1:
self.offline = (options.get('offline') == 'true'
or options.get('install-from-cache') == 'true')
self.fallback = fallback
self.hash_name = hash_name
self.logger = logger or logging.getLogger('zc.buildout')
@property
def download_cache(self):
if self.cache is not None:
return realpath(os.path.join(self.directory, self.cache))
@property
def cache_dir(self):
if self.download_cache is not None:
return os.path.join(self.download_cache, self.namespace or '')
def __call__(self, url, md5sum=None, path=None):
"""Download a file according to the utility's configuration.
url: URL to download
md5sum: MD5 checksum to match
path: where to place the downloaded file
Returns the path to the downloaded file.
"""
if self.cache:
local_path, is_temp = self.download_cached(url, md5sum)
else:
local_path, is_temp = self.download(url, md5sum, path)
return locate_at(local_path, path), is_temp
def download_cached(self, url, md5sum=None):
"""Download a file from a URL using the cache.
This method assumes that the cache has been configured. Optionally, it
raises a ChecksumError if a cached copy of a file has an MD5 mismatch,
but will not remove the copy in that case.
"""
if not os.path.exists(self.download_cache):
raise zc.buildout.UserError(
'The directory:\n'
'%r\n'
"to be used as a download cache doesn't exist.\n"
% self.download_cache)
cache_dir = self.cache_dir
if not os.path.exists(cache_dir):
os.mkdir(cache_dir)
cache_key = self.filename(url)
cached_path = os.path.join(cache_dir, cache_key)
self.logger.debug('Searching cache at %s' % cache_dir)
if os.path.isfile(cached_path):
is_temp = False
if self.fallback:
try:
_, is_temp = self.download(url, md5sum, cached_path)
except ChecksumError:
raise
except Exception:
pass
if not check_md5sum(cached_path, md5sum):
raise ChecksumError(
'MD5 checksum mismatch for cached download '
'from %r at %r' % (url, cached_path))
self.logger.debug('Using cache file %s' % cached_path)
else:
self.logger.debug('Cache miss; will cache %s as %s' %
(url, cached_path))
_, is_temp = self.download(url, md5sum, cached_path)
return cached_path, is_temp
def download(self, url, md5sum=None, path=None):
"""Download a file from a URL to a given or temporary path.
An online resource is always downloaded to a temporary file and moved
to the specified path only after the download is complete and the
checksum (if given) matches. If path is None, the temporary file is
returned and the client code is responsible for cleaning it up.
"""
if re.match(r"^[A-Za-z]:\\", url):
url = 'file:' + url
parsed_url = urlparse.urlparse(url, 'file')
url_scheme, _, url_path = parsed_url[:3]
if url_scheme == 'file':
self.logger.debug('Using local resource %s' % url)
if not check_md5sum(url_path, md5sum):
raise ChecksumError(
'MD5 checksum mismatch for local resource at %r.' %
url_path)
return locate_at(url_path, path), False
if self.offline:
raise zc.buildout.UserError(
"Couldn't download %r in offline mode." % url)
self.logger.info('Downloading %s' % url)
urllib._urlopener = url_opener
handle, tmp_path = tempfile.mkstemp(prefix='buildout-')
try:
try:
tmp_path, headers = urllib.urlretrieve(url, tmp_path)
if not check_md5sum(tmp_path, md5sum):
raise ChecksumError(
'MD5 checksum mismatch downloading %r' % url)
finally:
os.close(handle)
except:
os.remove(tmp_path)
raise
if path:
shutil.move(tmp_path, path)
return path, False
else:
return tmp_path, True
def filename(self, url):
"""Determine a file name from a URL according to the configuration.
"""
if self.hash_name:
return md5(url).hexdigest()
else:
if re.match(r"^[A-Za-z]:\\", url):
url = 'file:' + url
parsed = urlparse.urlparse(url, 'file')
url_path = parsed[2]
if parsed[0] == 'file':
while True:
url_path, name = os.path.split(url_path)
if name:
return name
if not url_path:
break
else:
for name in reversed(url_path.split('/')):
if name:
return name
url_host, url_port = parsed[-2:]
return '%s:%s' % (url_host, url_port)
def check_md5sum(path, md5sum):
"""Tell whether the MD5 checksum of the file at path matches.
No checksum being given is considered a match.
"""
if md5sum is None:
return True
f = open(path, 'rb')
checksum = md5()
try:
chunk = f.read(2**16)
while chunk:
checksum.update(chunk)
chunk = f.read(2**16)
return checksum.hexdigest() == md5sum
finally:
f.close()
def remove(path):
if os.path.exists(path):
os.remove(path)
def locate_at(source, dest):
if dest is None or realpath(dest) == realpath(source):
return source
try:
os.link(source, dest)
except (AttributeError, OSError):
shutil.copyfile(source, dest)
return dest