############################################################################## # # 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