from __future__ import absolute_import import cgi import email.utils import getpass import json import logging import mimetypes import os import platform import re import shutil import sys from pip._vendor import requests, six, urllib3 from pip._vendor.cachecontrol import CacheControlAdapter from pip._vendor.cachecontrol.caches import FileCache from pip._vendor.lockfile import LockError from pip._vendor.requests.adapters import BaseAdapter, HTTPAdapter from pip._vendor.requests.auth import AuthBase, HTTPBasicAuth from pip._vendor.requests.models import CONTENT_CHUNK_SIZE, Response from pip._vendor.requests.structures import CaseInsensitiveDict from pip._vendor.requests.utils import get_netrc_auth # NOTE: XMLRPC Client is not annotated in typeshed as on 2017-07-17, which is # why we ignore the type on this import from pip._vendor.six.moves import xmlrpc_client # type: ignore from pip._vendor.six.moves.urllib import parse as urllib_parse from pip._vendor.six.moves.urllib import request as urllib_request from pip._vendor.urllib3.util import IS_PYOPENSSL import pip from pip._internal.exceptions import HashMismatch, InstallationError from pip._internal.locations import write_delete_marker_file from pip._internal.models.index import PyPI from pip._internal.utils.encoding import auto_decode from pip._internal.utils.filesystem import check_path_owner from pip._internal.utils.glibc import libc_ver from pip._internal.utils.logging import indent_log from pip._internal.utils.misc import ( ARCHIVE_EXTENSIONS, ask_path_exists, backup_dir, call_subprocess, consume, display_path, format_size, get_installed_version, rmtree, split_auth_from_netloc, splitext, unpack_file, ) from pip._internal.utils.setuptools_build import SETUPTOOLS_SHIM from pip._internal.utils.temp_dir import TempDirectory from pip._internal.utils.typing import MYPY_CHECK_RUNNING from pip._internal.utils.ui import DownloadProgressProvider from pip._internal.vcs import vcs if MYPY_CHECK_RUNNING: from typing import ( # noqa: F401 Optional, Tuple, Dict, IO, Text, Union ) from pip._internal.models.link import Link # noqa: F401 from pip._internal.utils.hashes import Hashes # noqa: F401 from pip._internal.vcs import AuthInfo # noqa: F401 try: import ssl # noqa except ImportError: ssl = None HAS_TLS = (ssl is not None) or IS_PYOPENSSL __all__ = ['get_file_content', 'is_url', 'url_to_path', 'path_to_url', 'is_archive_file', 'unpack_vcs_link', 'unpack_file_url', 'is_vcs_url', 'is_file_url', 'unpack_http_url', 'unpack_url'] logger = logging.getLogger(__name__) def user_agent(): """ Return a string representing the user agent. """ data = { "installer": {"name": "pip", "version": pip.__version__}, "python": platform.python_version(), "implementation": { "name": platform.python_implementation(), }, } if data["implementation"]["name"] == 'CPython': data["implementation"]["version"] = platform.python_version() elif data["implementation"]["name"] == 'PyPy': if sys.pypy_version_info.releaselevel == 'final': pypy_version_info = sys.pypy_version_info[:3] else: pypy_version_info = sys.pypy_version_info data["implementation"]["version"] = ".".join( [str(x) for x in pypy_version_info] ) elif data["implementation"]["name"] == 'Jython': # Complete Guess data["implementation"]["version"] = platform.python_version() elif data["implementation"]["name"] == 'IronPython': # Complete Guess data["implementation"]["version"] = platform.python_version() if sys.platform.startswith("linux"): from pip._vendor import distro distro_infos = dict(filter( lambda x: x[1], zip(["name", "version", "id"], distro.linux_distribution()), )) libc = dict(filter( lambda x: x[1], zip(["lib", "version"], libc_ver()), )) if libc: distro_infos["libc"] = libc if distro_infos: data["distro"] = distro_infos if sys.platform.startswith("darwin") and platform.mac_ver()[0]: data["distro"] = {"name": "macOS", "version": platform.mac_ver()[0]} if platform.system(): data.setdefault("system", {})["name"] = platform.system() if platform.release(): data.setdefault("system", {})["release"] = platform.release() if platform.machine(): data["cpu"] = platform.machine() if HAS_TLS: data["openssl_version"] = ssl.OPENSSL_VERSION setuptools_version = get_installed_version("setuptools") if setuptools_version is not None: data["setuptools_version"] = setuptools_version return "{data[installer][name]}/{data[installer][version]} {json}".format( data=data, json=json.dumps(data, separators=(",", ":"), sort_keys=True), ) class MultiDomainBasicAuth(AuthBase): def __init__(self, prompting=True): # type: (bool) -> None self.prompting = prompting self.passwords = {} # type: Dict[str, AuthInfo] def __call__(self, req): parsed = urllib_parse.urlparse(req.url) # Split the credentials from the netloc. netloc, url_user_password = split_auth_from_netloc(parsed.netloc) # Set the url of the request to the url without any credentials req.url = urllib_parse.urlunparse(parsed[:1] + (netloc,) + parsed[2:]) # Use any stored credentials that we have for this netloc username, password = self.passwords.get(netloc, (None, None)) # Use the credentials embedded in the url if we have none stored if username is None: username, password = url_user_password # Get creds from netrc if we still don't have them if username is None and password is None: netrc_auth = get_netrc_auth(req.url) username, password = netrc_auth if netrc_auth else (None, None) if username or password: # Store the username and password self.passwords[netloc] = (username, password) # Send the basic auth with this request req = HTTPBasicAuth(username or "", password or "")(req) # Attach a hook to handle 401 responses req.register_hook("response", self.handle_401) return req def handle_401(self, resp, **kwargs): # We only care about 401 responses, anything else we want to just # pass through the actual response if resp.status_code != 401: return resp # We are not able to prompt the user so simply return the response if not self.prompting: return resp parsed = urllib_parse.urlparse(resp.url) # Prompt the user for a new username and password username = six.moves.input("User for %s: " % parsed.netloc) password = getpass.getpass("Password: ") # Store the new username and password to use for future requests if username or password: self.passwords[parsed.netloc] = (username, password) # Consume content and release the original connection to allow our new # request to reuse the same one. resp.content resp.raw.release_conn() # Add our new username and password to the request req = HTTPBasicAuth(username or "", password or "")(resp.request) req.register_hook("response", self.warn_on_401) # Send our new request new_resp = resp.connection.send(req, **kwargs) new_resp.history.append(resp) return new_resp def warn_on_401(self, resp, **kwargs): # warn user that they provided incorrect credentials if resp.status_code == 401: logger.warning('401 Error, Credentials not correct for %s', resp.request.url) class LocalFSAdapter(BaseAdapter): def send(self, request, stream=None, timeout=None, verify=None, cert=None, proxies=None): pathname = url_to_path(request.url) resp = Response() resp.status_code = 200 resp.url = request.url try: stats = os.stat(pathname) except OSError as exc: resp.status_code = 404 resp.raw = exc else: modified = email.utils.formatdate(stats.st_mtime, usegmt=True) content_type = mimetypes.guess_type(pathname)[0] or "text/plain" resp.headers = CaseInsensitiveDict({ "Content-Type": content_type, "Content-Length": stats.st_size, "Last-Modified": modified, }) resp.raw = open(pathname, "rb") resp.close = resp.raw.close return resp def close(self): pass class SafeFileCache(FileCache): """ A file based cache which is safe to use even when the target directory may not be accessible or writable. """ def __init__(self, *args, **kwargs): super(SafeFileCache, self).__init__(*args, **kwargs) # Check to ensure that the directory containing our cache directory # is owned by the user current executing pip. If it does not exist # we will check the parent directory until we find one that does exist. # If it is not owned by the user executing pip then we will disable # the cache and log a warning. if not check_path_owner(self.directory): logger.warning( "The directory '%s' or its parent directory is not owned by " "the current user and the cache has been disabled. Please " "check the permissions and owner of that directory. If " "executing pip with sudo, you may want sudo's -H flag.", self.directory, ) # Set our directory to None to disable the Cache self.directory = None def get(self, *args, **kwargs): # If we don't have a directory, then the cache should be a no-op. if self.directory is None: return try: return super(SafeFileCache, self).get(*args, **kwargs) except (LockError, OSError, IOError): # We intentionally silence this error, if we can't access the cache # then we can just skip caching and process the request as if # caching wasn't enabled. pass def set(self, *args, **kwargs): # If we don't have a directory, then the cache should be a no-op. if self.directory is None: return try: return super(SafeFileCache, self).set(*args, **kwargs) except (LockError, OSError, IOError): # We intentionally silence this error, if we can't access the cache # then we can just skip caching and process the request as if # caching wasn't enabled. pass def delete(self, *args, **kwargs): # If we don't have a directory, then the cache should be a no-op. if self.directory is None: return try: return super(SafeFileCache, self).delete(*args, **kwargs) except (LockError, OSError, IOError): # We intentionally silence this error, if we can't access the cache # then we can just skip caching and process the request as if # caching wasn't enabled. pass class InsecureHTTPAdapter(HTTPAdapter): def cert_verify(self, conn, url, verify, cert): conn.cert_reqs = 'CERT_NONE' conn.ca_certs = None class PipSession(requests.Session): timeout = None # type: Optional[int] def __init__(self, *args, **kwargs): retries = kwargs.pop("retries", 0) cache = kwargs.pop("cache", None) insecure_hosts = kwargs.pop("insecure_hosts", []) super(PipSession, self).__init__(*args, **kwargs) # Attach our User Agent to the request self.headers["User-Agent"] = user_agent() # Attach our Authentication handler to the session self.auth = MultiDomainBasicAuth() # Create our urllib3.Retry instance which will allow us to customize # how we handle retries. retries = urllib3.Retry( # Set the total number of retries that a particular request can # have. total=retries, # A 503 error from PyPI typically means that the Fastly -> Origin # connection got interrupted in some way. A 503 error in general # is typically considered a transient error so we'll go ahead and # retry it. # A 500 may indicate transient error in Amazon S3 # A 520 or 527 - may indicate transient error in CloudFlare status_forcelist=[500, 503, 520, 527], # Add a small amount of back off between failed requests in # order to prevent hammering the service. backoff_factor=0.25, ) # We want to _only_ cache responses on securely fetched origins. We do # this because we can't validate the response of an insecurely fetched # origin, and we don't want someone to be able to poison the cache and # require manual eviction from the cache to fix it. if cache: secure_adapter = CacheControlAdapter( cache=SafeFileCache(cache, use_dir_lock=True), max_retries=retries, ) else: secure_adapter = HTTPAdapter(max_retries=retries) # Our Insecure HTTPAdapter disables HTTPS validation. It does not # support caching (see above) so we'll use it for all http:// URLs as # well as any https:// host that we've marked as ignoring TLS errors # for. insecure_adapter = InsecureHTTPAdapter(max_retries=retries) self.mount("https://", secure_adapter) self.mount("http://", insecure_adapter) # Enable file:// urls self.mount("file://", LocalFSAdapter()) # We want to use a non-validating adapter for any requests which are # deemed insecure. for host in insecure_hosts: self.mount("https://{}/".format(host), insecure_adapter) def request(self, method, url, *args, **kwargs): # Allow setting a default timeout on a session kwargs.setdefault("timeout", self.timeout) # Dispatch the actual request return super(PipSession, self).request(method, url, *args, **kwargs) def get_file_content(url, comes_from=None, session=None): # type: (str, Optional[str], Optional[PipSession]) -> Tuple[str, Text] """Gets the content of a file; it may be a filename, file: URL, or http: URL. Returns (location, content). Content is unicode. :param url: File path or url. :param comes_from: Origin description of requirements. :param session: Instance of pip.download.PipSession. """ if session is None: raise TypeError( "get_file_content() missing 1 required keyword argument: 'session'" ) match = _scheme_re.search(url) if match: scheme = match.group(1).lower() if (scheme == 'file' and comes_from and comes_from.startswith('http')): raise InstallationError( 'Requirements file %s references URL %s, which is local' % (comes_from, url)) if scheme == 'file': path = url.split(':', 1)[1] path = path.replace('\\', '/') match = _url_slash_drive_re.match(path) if match: path = match.group(1) + ':' + path.split('|', 1)[1] path = urllib_parse.unquote(path) if path.startswith('/'): path = '/' + path.lstrip('/') url = path else: # FIXME: catch some errors resp = session.get(url) resp.raise_for_status() return resp.url, resp.text try: with open(url, 'rb') as f: content = auto_decode(f.read()) except IOError as exc: raise InstallationError( 'Could not open requirements file: %s' % str(exc) ) return url, content _scheme_re = re.compile(r'^(http|https|file):', re.I) _url_slash_drive_re = re.compile(r'/*([a-z])\|', re.I) def is_url(name): # type: (Union[str, Text]) -> bool """Returns true if the name looks like a URL""" if ':' not in name: return False scheme = name.split(':', 1)[0].lower() return scheme in ['http', 'https', 'file', 'ftp'] + vcs.all_schemes def url_to_path(url): # type: (str) -> str """ Convert a file: URL to a path. """ assert url.startswith('file:'), ( "You can only turn file: urls into filenames (not %r)" % url) _, netloc, path, _, _ = urllib_parse.urlsplit(url) # if we have a UNC path, prepend UNC share notation if netloc: netloc = '\\\\' + netloc path = urllib_request.url2pathname(netloc + path) return path def path_to_url(path): # type: (Union[str, Text]) -> str """ Convert a path to a file: URL. The path will be made absolute and have quoted path parts. """ path = os.path.normpath(os.path.abspath(path)) url = urllib_parse.urljoin('file:', urllib_request.pathname2url(path)) return url def is_archive_file(name): # type: (str) -> bool """Return True if `name` is a considered as an archive file.""" ext = splitext(name)[1].lower() if ext in ARCHIVE_EXTENSIONS: return True return False def unpack_vcs_link(link, location): vcs_backend = _get_used_vcs_backend(link) vcs_backend.unpack(location) def _get_used_vcs_backend(link): for backend in vcs.backends: if link.scheme in backend.schemes: vcs_backend = backend(link.url) return vcs_backend def is_vcs_url(link): # type: (Link) -> bool return bool(_get_used_vcs_backend(link)) def is_file_url(link): # type: (Link) -> bool return link.url.lower().startswith('file:') def is_dir_url(link): # type: (Link) -> bool """Return whether a file:// Link points to a directory. ``link`` must not have any other scheme but file://. Call is_file_url() first. """ link_path = url_to_path(link.url_without_fragment) return os.path.isdir(link_path) def _progress_indicator(iterable, *args, **kwargs): return iterable def _download_url( resp, # type: Response link, # type: Link content_file, # type: IO hashes, # type: Hashes progress_bar # type: str ): # type: (...) -> None try: total_length = int(resp.headers['content-length']) except (ValueError, KeyError, TypeError): total_length = 0 cached_resp = getattr(resp, "from_cache", False) if logger.getEffectiveLevel() > logging.INFO: show_progress = False elif cached_resp: show_progress = False elif total_length > (40 * 1000): show_progress = True elif not total_length: show_progress = True else: show_progress = False show_url = link.show_url def resp_read(chunk_size): try: # Special case for urllib3. for chunk in resp.raw.stream( chunk_size, # We use decode_content=False here because we don't # want urllib3 to mess with the raw bytes we get # from the server. If we decompress inside of # urllib3 then we cannot verify the checksum # because the checksum will be of the compressed # file. This breakage will only occur if the # server adds a Content-Encoding header, which # depends on how the server was configured: # - Some servers will notice that the file isn't a # compressible file and will leave the file alone # and with an empty Content-Encoding # - Some servers will notice that the file is # already compressed and will leave the file # alone and will add a Content-Encoding: gzip # header # - Some servers won't notice anything at all and # will take a file that's already been compressed # and compress it again and set the # Content-Encoding: gzip header # # By setting this not to decode automatically we # hope to eliminate problems with the second case. decode_content=False): yield chunk except AttributeError: # Standard file-like object. while True: chunk = resp.raw.read(chunk_size) if not chunk: break yield chunk def written_chunks(chunks): for chunk in chunks: content_file.write(chunk) yield chunk progress_indicator = _progress_indicator if link.netloc == PyPI.netloc: url = show_url else: url = link.url_without_fragment if show_progress: # We don't show progress on cached responses progress_indicator = DownloadProgressProvider(progress_bar, max=total_length) if total_length: logger.info("Downloading %s (%s)", url, format_size(total_length)) else: logger.info("Downloading %s", url) elif cached_resp: logger.info("Using cached %s", url) else: logger.info("Downloading %s", url) logger.debug('Downloading from URL %s', link) downloaded_chunks = written_chunks( progress_indicator( resp_read(CONTENT_CHUNK_SIZE), CONTENT_CHUNK_SIZE ) ) if hashes: hashes.check_against_chunks(downloaded_chunks) else: consume(downloaded_chunks) def _copy_file(filename, location, link): copy = True download_location = os.path.join(location, link.filename) if os.path.exists(download_location): response = ask_path_exists( 'The file %s exists. (i)gnore, (w)ipe, (b)ackup, (a)abort' % display_path(download_location), ('i', 'w', 'b', 'a')) if response == 'i': copy = False elif response == 'w': logger.warning('Deleting %s', display_path(download_location)) os.remove(download_location) elif response == 'b': dest_file = backup_dir(download_location) logger.warning( 'Backing up %s to %s', display_path(download_location), display_path(dest_file), ) shutil.move(download_location, dest_file) elif response == 'a': sys.exit(-1) if copy: shutil.copy(filename, download_location) logger.info('Saved %s', display_path(download_location)) def unpack_http_url( link, # type: Link location, # type: str download_dir=None, # type: Optional[str] session=None, # type: Optional[PipSession] hashes=None, # type: Optional[Hashes] progress_bar="on" # type: str ): # type: (...) -> None if session is None: raise TypeError( "unpack_http_url() missing 1 required keyword argument: 'session'" ) with TempDirectory(kind="unpack") as temp_dir: # If a download dir is specified, is the file already downloaded there? already_downloaded_path = None if download_dir: already_downloaded_path = _check_download_dir(link, download_dir, hashes) if already_downloaded_path: from_path = already_downloaded_path content_type = mimetypes.guess_type(from_path)[0] else: # let's download to a tmp dir from_path, content_type = _download_http_url(link, session, temp_dir.path, hashes, progress_bar) # unpack the archive to the build dir location. even when only # downloading archives, they have to be unpacked to parse dependencies unpack_file(from_path, location, content_type, link) # a download dir is specified; let's copy the archive there if download_dir and not already_downloaded_path: _copy_file(from_path, download_dir, link) if not already_downloaded_path: os.unlink(from_path) def unpack_file_url( link, # type: Link location, # type: str download_dir=None, # type: Optional[str] hashes=None # type: Optional[Hashes] ): # type: (...) -> None """Unpack link into location. If download_dir is provided and link points to a file, make a copy of the link file inside download_dir. """ link_path = url_to_path(link.url_without_fragment) # If it's a url to a local directory if is_dir_url(link): if os.path.isdir(location): rmtree(location) shutil.copytree(link_path, location, symlinks=True) if download_dir: logger.info('Link is a directory, ignoring download_dir') return # If --require-hashes is off, `hashes` is either empty, the # link's embedded hash, or MissingHashes; it is required to # match. If --require-hashes is on, we are satisfied by any # hash in `hashes` matching: a URL-based or an option-based # one; no internet-sourced hash will be in `hashes`. if hashes: hashes.check_against_path(link_path) # If a download dir is specified, is the file already there and valid? already_downloaded_path = None if download_dir: already_downloaded_path = _check_download_dir(link, download_dir, hashes) if already_downloaded_path: from_path = already_downloaded_path else: from_path = link_path content_type = mimetypes.guess_type(from_path)[0] # unpack the archive to the build dir location. even when only downloading # archives, they have to be unpacked to parse dependencies unpack_file(from_path, location, content_type, link) # a download dir is specified and not already downloaded if download_dir and not already_downloaded_path: _copy_file(from_path, download_dir, link) def _copy_dist_from_dir(link_path, location): """Copy distribution files in `link_path` to `location`. Invoked when user requests to install a local directory. E.g.: pip install . pip install ~/dev/git-repos/python-prompt-toolkit """ # Note: This is currently VERY SLOW if you have a lot of data in the # directory, because it copies everything with `shutil.copytree`. # What it should really do is build an sdist and install that. # See https://github.com/pypa/pip/issues/2195 if os.path.isdir(location): rmtree(location) # build an sdist setup_py = 'setup.py' sdist_args = [sys.executable] sdist_args.append('-c') sdist_args.append(SETUPTOOLS_SHIM % setup_py) sdist_args.append('sdist') sdist_args += ['--dist-dir', location] logger.info('Running setup.py sdist for %s', link_path) with indent_log(): call_subprocess(sdist_args, cwd=link_path, show_stdout=False) # unpack sdist into `location` sdist = os.path.join(location, os.listdir(location)[0]) logger.info('Unpacking sdist %s into %s', sdist, location) unpack_file(sdist, location, content_type=None, link=None) class PipXmlrpcTransport(xmlrpc_client.Transport): """Provide a `xmlrpclib.Transport` implementation via a `PipSession` object. """ def __init__(self, index_url, session, use_datetime=False): xmlrpc_client.Transport.__init__(self, use_datetime) index_parts = urllib_parse.urlparse(index_url) self._scheme = index_parts.scheme self._session = session def request(self, host, handler, request_body, verbose=False): parts = (self._scheme, host, handler, None, None, None) url = urllib_parse.urlunparse(parts) try: headers = {'Content-Type': 'text/xml'} response = self._session.post(url, data=request_body, headers=headers, stream=True) response.raise_for_status() self.verbose = verbose return self.parse_response(response.raw) except requests.HTTPError as exc: logger.critical( "HTTP error %s while getting %s", exc.response.status_code, url, ) raise def unpack_url( link, # type: Optional[Link] location, # type: Optional[str] download_dir=None, # type: Optional[str] only_download=False, # type: bool session=None, # type: Optional[PipSession] hashes=None, # type: Optional[Hashes] progress_bar="on" # type: str ): # type: (...) -> None """Unpack link. If link is a VCS link: if only_download, export into download_dir and ignore location else unpack into location for other types of link: - unpack into location - if download_dir, copy the file into download_dir - if only_download, mark location for deletion :param hashes: A Hashes object, one of whose embedded hashes must match, or HashMismatch will be raised. If the Hashes is empty, no matches are required, and unhashable types of requirements (like VCS ones, which would ordinarily raise HashUnsupported) are allowed. """ # non-editable vcs urls if is_vcs_url(link): unpack_vcs_link(link, location) # file urls elif is_file_url(link): unpack_file_url(link, location, download_dir, hashes=hashes) # http urls else: if session is None: session = PipSession() unpack_http_url( link, location, download_dir, session, hashes=hashes, progress_bar=progress_bar ) if only_download: write_delete_marker_file(location) def _download_http_url( link, # type: Link session, # type: PipSession temp_dir, # type: str hashes, # type: Hashes progress_bar # type: str ): # type: (...) -> Tuple[str, str] """Download link url into temp_dir using provided session""" target_url = link.url.split('#', 1)[0] try: resp = session.get( target_url, # We use Accept-Encoding: identity here because requests # defaults to accepting compressed responses. This breaks in # a variety of ways depending on how the server is configured. # - Some servers will notice that the file isn't a compressible # file and will leave the file alone and with an empty # Content-Encoding # - Some servers will notice that the file is already # compressed and will leave the file alone and will add a # Content-Encoding: gzip header # - Some servers won't notice anything at all and will take # a file that's already been compressed and compress it again # and set the Content-Encoding: gzip header # By setting this to request only the identity encoding We're # hoping to eliminate the third case. Hopefully there does not # exist a server which when given a file will notice it is # already compressed and that you're not asking for a # compressed file and will then decompress it before sending # because if that's the case I don't think it'll ever be # possible to make this work. headers={"Accept-Encoding": "identity"}, stream=True, ) resp.raise_for_status() except requests.HTTPError as exc: logger.critical( "HTTP error %s while getting %s", exc.response.status_code, link, ) raise content_type = resp.headers.get('content-type', '') filename = link.filename # fallback # Have a look at the Content-Disposition header for a better guess content_disposition = resp.headers.get('content-disposition') if content_disposition: type, params = cgi.parse_header(content_disposition) # We use ``or`` here because we don't want to use an "empty" value # from the filename param. filename = params.get('filename') or filename ext = splitext(filename)[1] if not ext: ext = mimetypes.guess_extension(content_type) if ext: filename += ext if not ext and link.url != resp.url: ext = os.path.splitext(resp.url)[1] if ext: filename += ext file_path = os.path.join(temp_dir, filename) with open(file_path, 'wb') as content_file: _download_url(resp, link, content_file, hashes, progress_bar) return file_path, content_type def _check_download_dir(link, download_dir, hashes): # type: (Link, str, Hashes) -> Optional[str] """ Check download_dir for previously downloaded file with correct hash If a correct file is found return its path else None """ download_path = os.path.join(download_dir, link.filename) if os.path.exists(download_path): # If already downloaded, does its hash match? logger.info('File was already downloaded %s', download_path) if hashes: try: hashes.check_against_path(download_path) except HashMismatch: logger.warning( 'Previously-downloaded file %s has bad hash. ' 'Re-downloading.', download_path ) os.unlink(download_path) return None return download_path return None