Source code for astropy.utils.data

# Licensed under a 3-clause BSD style license - see LICENSE.rst

"""Functions for accessing, downloading, and caching data files."""

import atexit
import contextlib
import errno
import fnmatch
import hashlib
import os
import io
import pathlib
import re
import shutil
import socket
import sys
import urllib.request
import urllib.error
import urllib.parse
import zipfile
import ftplib

from tempfile import NamedTemporaryFile, gettempdir, TemporaryDirectory, mkdtemp
from warnings import warn

import astropy.config.paths
from astropy import config as _config
from astropy.utils.exceptions import AstropyWarning
from astropy.utils.introspection import find_current_module, resolve_name

# Order here determines order in the autosummary
__all__ = [
    'Conf', 'conf',
    'download_file', 'download_files_in_parallel',
    'get_readable_fileobj',
    'get_pkg_data_fileobj', 'get_pkg_data_filename',
    'get_pkg_data_contents', 'get_pkg_data_fileobjs',
    'get_pkg_data_filenames',
    'is_url_in_cache', 'get_cached_urls',
    'cache_total_size', 'cache_contents',
    'export_download_cache', 'import_download_cache', 'import_file_to_cache',
    'check_download_cache',
    'clear_download_cache',
    'compute_hash',
    'get_free_space_in_dir',
    'check_free_space_in_dir',
    'get_file_contents',
    'CacheMissingWarning',
]

_dataurls_to_alias = {}


[docs]class Conf(_config.ConfigNamespace): """ Configuration parameters for `astropy.utils.data`. """ dataurl = _config.ConfigItem( 'http://data.astropy.org/', 'Primary URL for astropy remote data site.') dataurl_mirror = _config.ConfigItem( 'http://www.astropy.org/astropy-data/', 'Mirror URL for astropy remote data site.') default_http_user_agent = _config.ConfigItem( 'astropy', 'Default User-Agent for HTTP request headers. This can be overwritten ' 'for a particular call via http_headers option, where available. ' 'This only provides the default value when not set by https_headers.') remote_timeout = _config.ConfigItem( 10., 'Time to wait for remote data queries (in seconds). Set this to zero ' 'to prevent any attempt to download anything.', aliases=['astropy.coordinates.name_resolve.name_resolve_timeout']) compute_hash_block_size = _config.ConfigItem( 2 ** 16, # 64K 'Block size for computing file hashes.') download_block_size = _config.ConfigItem( 2 ** 16, # 64K 'Number of bytes of remote data to download per step.') download_cache_lock_attempts = _config.ConfigItem( 5, 'Unused; cache no longer locked. Was: ' 'Number of seconds to wait for the cache lock to be free. It should ' 'normally only ever be held long enough to copy an already-downloaded ' 'file into the cache, so this will normally only run over if ' 'something goes wrong and the lock is left held by a dead process; ' 'the exception raised should indicate this and what to do to fix it.') delete_temporary_downloads_at_exit = _config.ConfigItem( True, 'If True, temporary download files created when the cache is ' 'inaccessible will be deleted at the end of the python session.')
conf = Conf()
[docs]class CacheMissingWarning(AstropyWarning): """ This warning indicates the standard cache directory is not accessible, with the first argument providing the warning message. If args[1] is present, it is a filename indicating the path to a temporary file that was created to store a remote data download in the absence of the cache. """
def _is_url(string): """ Test whether a string is a valid URL Parameters ---------- string : str The string to test """ url = urllib.parse.urlparse(string) # we can't just check that url.scheme is not an empty string, because # file paths in windows would return a non-empty scheme (e.g. e:\\ # returns 'e'). return url.scheme.lower() in ['http', 'https', 'ftp', 'sftp', 'ssh', 'file'] def _is_inside(path, parent_path): # We have to try realpath too to avoid issues with symlinks, but we leave # abspath because some systems like debian have the absolute path (with no # symlinks followed) match, but the real directories in different # locations, so need to try both cases. return os.path.abspath(path).startswith(os.path.abspath(parent_path)) \ or os.path.realpath(path).startswith(os.path.realpath(parent_path))
[docs]@contextlib.contextmanager def get_readable_fileobj(name_or_obj, encoding=None, cache=False, show_progress=True, remote_timeout=None, sources=None, http_headers=None): """Yield a readable, seekable file-like object from a file or URL. This supports passing filenames, URLs, and readable file-like objects, any of which can be compressed in gzip, bzip2 or lzma (xz) if the appropriate compression libraries are provided by the Python installation. Notes ----- This function is a context manager, and should be used for example as:: with get_readable_fileobj('file.dat') as f: contents = f.read() If a URL is provided and the cache is in use, the provided URL will be the name used in the cache. The contents may already be stored in the cache under this URL provided, they may be downloaded from this URL, or they may be downloaded from one of the locations listed in ``sources``. See `~download_file` for details. Parameters ---------- name_or_obj : str or file-like object The filename of the file to access (if given as a string), or the file-like object to access. If a file-like object, it must be opened in binary mode. encoding : str, optional When `None` (default), returns a file-like object with a ``read`` method that returns `str` (``unicode``) objects, using `locale.getpreferredencoding` as an encoding. This matches the default behavior of the built-in `open` when no ``mode`` argument is provided. When ``'binary'``, returns a file-like object where its ``read`` method returns `bytes` objects. When another string, it is the name of an encoding, and the file-like object's ``read`` method will return `str` (``unicode``) objects, decoded from binary using the given encoding. cache : bool or "update", optional Whether to cache the contents of remote URLs. If "update", check the remote URL for a new version but store the result in the cache. show_progress : bool, optional Whether to display a progress bar if the file is downloaded from a remote server. Default is `True`. remote_timeout : float Timeout for remote requests in seconds (default is the configurable `astropy.utils.data.Conf.remote_timeout`, which is 3s by default). Set this to zero to prevent any attempt at downloading. sources : list of str, optional If provided, a list of URLs to try to obtain the file from. The result will be stored under the original URL. The original URL will *not* be tried unless it is in this list; this is to prevent long waits for a primary server that is known to be inaccessible at the moment. http_headers : dict or None HTTP request headers to pass into ``urlopen`` if needed. (These headers are ignored if the protocol for the ``name_or_obj``/``sources`` entry is not a remote HTTP URL.) In the default case (None), the headers are ``User-Agent: some_value`` and ``Accept: */*``, where ``some_value`` is set by ``astropy.utils.data.conf.default_http_user_agent``. Returns ------- file : readable file-like object """ # close_fds is a list of file handles created by this function # that need to be closed. We don't want to always just close the # returned file handle, because it may simply be the file handle # passed in. In that case it is not the responsibility of this # function to close it: doing so could result in a "double close" # and an "invalid file descriptor" exception. PATH_TYPES = (str, pathlib.Path) close_fds = [] delete_fds = [] if remote_timeout is None: # use configfile default remote_timeout = conf.remote_timeout # Get a file object to the content if isinstance(name_or_obj, PATH_TYPES): # name_or_obj could be a Path object if pathlib is available name_or_obj = str(name_or_obj) is_url = _is_url(name_or_obj) if is_url: name_or_obj = download_file( name_or_obj, cache=cache, show_progress=show_progress, timeout=remote_timeout, sources=sources, http_headers=http_headers) fileobj = io.FileIO(name_or_obj, 'r') if is_url and not cache: delete_fds.append(fileobj) close_fds.append(fileobj) else: fileobj = name_or_obj # Check if the file object supports random access, and if not, # then wrap it in a BytesIO buffer. It would be nicer to use a # BufferedReader to avoid reading loading the whole file first, # but that is not compatible with streams or urllib2.urlopen # objects on Python 2.x. if not hasattr(fileobj, 'seek'): try: # py.path.LocalPath objects have .read() method but it uses # text mode, which won't work. .read_binary() does, and # surely other ducks would return binary contents when # called like this. # py.path.LocalPath is what comes from the tmpdir fixture # in pytest. fileobj = io.BytesIO(fileobj.read_binary()) except AttributeError: fileobj = io.BytesIO(fileobj.read()) # Now read enough bytes to look at signature signature = fileobj.read(4) fileobj.seek(0) if signature[:3] == b'\x1f\x8b\x08': # gzip import struct try: import gzip fileobj_new = gzip.GzipFile(fileobj=fileobj, mode='rb') fileobj_new.read(1) # need to check that the file is really gzip except (OSError, EOFError, struct.error): # invalid gzip file fileobj.seek(0) fileobj_new.close() else: fileobj_new.seek(0) fileobj = fileobj_new elif signature[:3] == b'BZh': # bzip2 try: import bz2 except ImportError: for fd in close_fds: fd.close() raise ModuleNotFoundError( "This Python installation does not provide the bz2 module.") try: # bz2.BZ2File does not support file objects, only filenames, so we # need to write the data to a temporary file with NamedTemporaryFile("wb", delete=False) as tmp: tmp.write(fileobj.read()) tmp.close() fileobj_new = bz2.BZ2File(tmp.name, mode='rb') fileobj_new.read(1) # need to check that the file is really bzip2 except OSError: # invalid bzip2 file fileobj.seek(0) fileobj_new.close() # raise else: fileobj_new.seek(0) close_fds.append(fileobj_new) fileobj = fileobj_new elif signature[:3] == b'\xfd7z': # xz try: import lzma fileobj_new = lzma.LZMAFile(fileobj, mode='rb') fileobj_new.read(1) # need to check that the file is really xz except ImportError: for fd in close_fds: fd.close() raise ModuleNotFoundError( "This Python installation does not provide the lzma module.") except (OSError, EOFError): # invalid xz file fileobj.seek(0) fileobj_new.close() # should we propagate this to the caller to signal bad content? # raise ValueError(e) else: fileobj_new.seek(0) fileobj = fileobj_new # By this point, we have a file, io.FileIO, gzip.GzipFile, bz2.BZ2File # or lzma.LZMAFile instance opened in binary mode (that is, read # returns bytes). Now we need to, if requested, wrap it in a # io.TextIOWrapper so read will return unicode based on the # encoding parameter. needs_textio_wrapper = encoding != 'binary' if needs_textio_wrapper: # A bz2.BZ2File can not be wrapped by a TextIOWrapper, # so we decompress it to a temporary file and then # return a handle to that. try: import bz2 except ImportError: pass else: if isinstance(fileobj, bz2.BZ2File): tmp = NamedTemporaryFile("wb", delete=False) data = fileobj.read() tmp.write(data) tmp.close() delete_fds.append(tmp) fileobj = io.FileIO(tmp.name, 'r') close_fds.append(fileobj) fileobj = io.BufferedReader(fileobj) fileobj = io.TextIOWrapper(fileobj, encoding=encoding) # Ensure that file is at the start - io.FileIO will for # example not always be at the start: # >>> import io # >>> f = open('test.fits', 'rb') # >>> f.read(4) # 'SIMP' # >>> f.seek(0) # >>> fileobj = io.FileIO(f.fileno()) # >>> fileobj.tell() # 4096L fileobj.seek(0) try: yield fileobj finally: for fd in close_fds: fd.close() for fd in delete_fds: os.remove(fd.name)
[docs]def get_file_contents(*args, **kwargs): """ Retrieves the contents of a filename or file-like object. See the `get_readable_fileobj` docstring for details on parameters. Returns ------- content The content of the file (as requested by ``encoding``). """ with get_readable_fileobj(*args, **kwargs) as f: return f.read()
[docs]@contextlib.contextmanager def get_pkg_data_fileobj(data_name, package=None, encoding=None, cache=True): """ Retrieves a data file from the standard locations for the package and provides the file as a file-like object that reads bytes. Parameters ---------- data_name : str Name/location of the desired data file. One of the following: * The name of a data file included in the source distribution. The path is relative to the module calling this function. For example, if calling from ``astropy.pkname``, use ``'data/file.dat'`` to get the file in ``astropy/pkgname/data/file.dat``. Double-dots can be used to go up a level. In the same example, use ``'../data/file.dat'`` to get ``astropy/data/file.dat``. * If a matching local file does not exist, the Astropy data server will be queried for the file. * A hash like that produced by `compute_hash` can be requested, prefixed by 'hash/' e.g. 'hash/34c33b3eb0d56eb9462003af249eff28'. The hash will first be searched for locally, and if not found, the Astropy data server will be queried. package : str, optional If specified, look for a file relative to the given package, rather than the default of looking relative to the calling module's package. encoding : str, optional When `None` (default), returns a file-like object with a ``read`` method returns `str` (``unicode``) objects, using `locale.getpreferredencoding` as an encoding. This matches the default behavior of the built-in `open` when no ``mode`` argument is provided. When ``'binary'``, returns a file-like object where its ``read`` method returns `bytes` objects. When another string, it is the name of an encoding, and the file-like object's ``read`` method will return `str` (``unicode``) objects, decoded from binary using the given encoding. cache : bool If True, the file will be downloaded and saved locally or the already-cached local copy will be accessed. If False, the file-like object will directly access the resource (e.g. if a remote URL is accessed, an object like that from `urllib.request.urlopen` is returned). Returns ------- fileobj : file-like An object with the contents of the data file available via ``read`` function. Can be used as part of a ``with`` statement, automatically closing itself after the ``with`` block. Raises ------ urllib.error.URLError If a remote file cannot be found. OSError If problems occur writing or reading a local file. Examples -------- This will retrieve a data file and its contents for the `astropy.wcs` tests:: >>> from astropy.utils.data import get_pkg_data_fileobj >>> with get_pkg_data_fileobj('data/3d_cd.hdr', ... package='astropy.wcs.tests') as fobj: ... fcontents = fobj.read() ... This next example would download a data file from the astropy data server because the ``allsky/allsky_rosat.fits`` file is not present in the source distribution. It will also save the file locally so the next time it is accessed it won't need to be downloaded.:: >>> from astropy.utils.data import get_pkg_data_fileobj >>> with get_pkg_data_fileobj('allsky/allsky_rosat.fits', ... encoding='binary') as fobj: # doctest: +REMOTE_DATA +IGNORE_OUTPUT ... fcontents = fobj.read() ... Downloading http://data.astropy.org/allsky/allsky_rosat.fits [Done] This does the same thing but does *not* cache it locally:: >>> with get_pkg_data_fileobj('allsky/allsky_rosat.fits', ... encoding='binary', cache=False) as fobj: # doctest: +REMOTE_DATA +IGNORE_OUTPUT ... fcontents = fobj.read() ... Downloading http://data.astropy.org/allsky/allsky_rosat.fits [Done] See Also -------- get_pkg_data_contents : returns the contents of a file or url as a bytes object get_pkg_data_filename : returns a local name for a file containing the data """ datafn = _find_pkg_data_path(data_name, package=package) if os.path.isdir(datafn): raise OSError("Tried to access a data file that's actually " "a package data directory") elif os.path.isfile(datafn): # local file with get_readable_fileobj(datafn, encoding=encoding) as fileobj: yield fileobj else: # remote file with get_readable_fileobj( conf.dataurl + data_name, encoding=encoding, cache=cache, sources=[conf.dataurl + data_name, conf.dataurl_mirror + data_name], ) as fileobj: # We read a byte to trigger any URLErrors fileobj.read(1) fileobj.seek(0) yield fileobj
[docs]def get_pkg_data_filename(data_name, package=None, show_progress=True, remote_timeout=None): """ Retrieves a data file from the standard locations for the package and provides a local filename for the data. This function is similar to `get_pkg_data_fileobj` but returns the file *name* instead of a readable file-like object. This means that this function must always cache remote files locally, unlike `get_pkg_data_fileobj`. Parameters ---------- data_name : str Name/location of the desired data file. One of the following: * The name of a data file included in the source distribution. The path is relative to the module calling this function. For example, if calling from ``astropy.pkname``, use ``'data/file.dat'`` to get the file in ``astropy/pkgname/data/file.dat``. Double-dots can be used to go up a level. In the same example, use ``'../data/file.dat'`` to get ``astropy/data/file.dat``. * If a matching local file does not exist, the Astropy data server will be queried for the file. * A hash like that produced by `compute_hash` can be requested, prefixed by 'hash/' e.g. 'hash/34c33b3eb0d56eb9462003af249eff28'. The hash will first be searched for locally, and if not found, the Astropy data server will be queried. package : str, optional If specified, look for a file relative to the given package, rather than the default of looking relative to the calling module's package. show_progress : bool, optional Whether to display a progress bar if the file is downloaded from a remote server. Default is `True`. remote_timeout : float Timeout for the requests in seconds (default is the configurable `astropy.utils.data.Conf.remote_timeout`, which is 3s by default). Set this to zero to prevent any attempt at downloading. Raises ------ urllib.error.URLError If a remote file cannot be found. OSError If problems occur writing or reading a local file. Returns ------- filename : str A file path on the local file system corresponding to the data requested in ``data_name``. Examples -------- This will retrieve the contents of the data file for the `astropy.wcs` tests:: >>> from astropy.utils.data import get_pkg_data_filename >>> fn = get_pkg_data_filename('data/3d_cd.hdr', ... package='astropy.wcs.tests') >>> with open(fn) as f: ... fcontents = f.read() ... This retrieves a data file by hash either locally or from the astropy data server:: >>> from astropy.utils.data import get_pkg_data_filename >>> fn = get_pkg_data_filename('hash/34c33b3eb0d56eb9462003af249eff28') # doctest: +SKIP >>> with open(fn) as f: ... fcontents = f.read() ... See Also -------- get_pkg_data_contents : returns the contents of a file or url as a bytes object get_pkg_data_fileobj : returns a file-like object with the data """ if remote_timeout is None: # use configfile default remote_timeout = conf.remote_timeout if data_name.startswith('hash/'): # first try looking for a local version if a hash is specified hashfn = _find_hash_fn(data_name[5:]) if hashfn is None: return download_file(conf.dataurl + data_name, cache=True, show_progress=show_progress, timeout=remote_timeout, sources=[conf.dataurl + data_name, conf.dataurl_mirror + data_name]) else: return hashfn else: fs_path = os.path.normpath(data_name) datafn = _find_pkg_data_path(fs_path, package=package) if os.path.isdir(datafn): raise OSError("Tried to access a data file that's actually " "a package data directory") elif os.path.isfile(datafn): # local file return datafn else: # remote file return download_file(conf.dataurl + data_name, cache=True, show_progress=show_progress, timeout=remote_timeout, sources=[conf.dataurl + data_name, conf.dataurl_mirror + data_name])
[docs]def get_pkg_data_contents(data_name, package=None, encoding=None, cache=True): """ Retrieves a data file from the standard locations and returns its contents as a bytes object. Parameters ---------- data_name : str Name/location of the desired data file. One of the following: * The name of a data file included in the source distribution. The path is relative to the module calling this function. For example, if calling from ``astropy.pkname``, use ``'data/file.dat'`` to get the file in ``astropy/pkgname/data/file.dat``. Double-dots can be used to go up a level. In the same example, use ``'../data/file.dat'`` to get ``astropy/data/file.dat``. * If a matching local file does not exist, the Astropy data server will be queried for the file. * A hash like that produced by `compute_hash` can be requested, prefixed by 'hash/' e.g. 'hash/34c33b3eb0d56eb9462003af249eff28'. The hash will first be searched for locally, and if not found, the Astropy data server will be queried. * A URL to some other file. package : str, optional If specified, look for a file relative to the given package, rather than the default of looking relative to the calling module's package. encoding : str, optional When `None` (default), returns a file-like object with a ``read`` method that returns `str` (``unicode``) objects, using `locale.getpreferredencoding` as an encoding. This matches the default behavior of the built-in `open` when no ``mode`` argument is provided. When ``'binary'``, returns a file-like object where its ``read`` method returns `bytes` objects. When another string, it is the name of an encoding, and the file-like object's ``read`` method will return `str` (``unicode``) objects, decoded from binary using the given encoding. cache : bool If True, the file will be downloaded and saved locally or the already-cached local copy will be accessed. If False, the file-like object will directly access the resource (e.g. if a remote URL is accessed, an object like that from `urllib.request.urlopen` is returned). Returns ------- contents : bytes The complete contents of the file as a bytes object. Raises ------ urllib.error.URLError If a remote file cannot be found. OSError If problems occur writing or reading a local file. See Also -------- get_pkg_data_fileobj : returns a file-like object with the data get_pkg_data_filename : returns a local name for a file containing the data """ with get_pkg_data_fileobj(data_name, package=package, encoding=encoding, cache=cache) as fd: contents = fd.read() return contents
[docs]def get_pkg_data_filenames(datadir, package=None, pattern='*'): """ Returns the path of all of the data files in a given directory that match a given glob pattern. Parameters ---------- datadir : str Name/location of the desired data files. One of the following: * The name of a directory included in the source distribution. The path is relative to the module calling this function. For example, if calling from ``astropy.pkname``, use ``'data'`` to get the files in ``astropy/pkgname/data``. * Remote URLs are not currently supported. package : str, optional If specified, look for a file relative to the given package, rather than the default of looking relative to the calling module's package. pattern : str, optional A UNIX-style filename glob pattern to match files. See the `glob` module in the standard library for more information. By default, matches all files. Returns ------- filenames : iterator of str Paths on the local filesystem in *datadir* matching *pattern*. Examples -------- This will retrieve the contents of the data file for the `astropy.wcs` tests:: >>> from astropy.utils.data import get_pkg_data_filenames >>> for fn in get_pkg_data_filenames('data/maps', 'astropy.wcs.tests', ... '*.hdr'): ... with open(fn) as f: ... fcontents = f.read() ... """ path = _find_pkg_data_path(datadir, package=package) if os.path.isfile(path): raise OSError( "Tried to access a data directory that's actually " "a package data file") elif os.path.isdir(path): for filename in os.listdir(path): if fnmatch.fnmatch(filename, pattern): yield os.path.join(path, filename) else: raise OSError("Path not found")
[docs]def get_pkg_data_fileobjs(datadir, package=None, pattern='*', encoding=None): """ Returns readable file objects for all of the data files in a given directory that match a given glob pattern. Parameters ---------- datadir : str Name/location of the desired data files. One of the following: * The name of a directory included in the source distribution. The path is relative to the module calling this function. For example, if calling from ``astropy.pkname``, use ``'data'`` to get the files in ``astropy/pkgname/data`` * Remote URLs are not currently supported package : str, optional If specified, look for a file relative to the given package, rather than the default of looking relative to the calling module's package. pattern : str, optional A UNIX-style filename glob pattern to match files. See the `glob` module in the standard library for more information. By default, matches all files. encoding : str, optional When `None` (default), returns a file-like object with a ``read`` method that returns `str` (``unicode``) objects, using `locale.getpreferredencoding` as an encoding. This matches the default behavior of the built-in `open` when no ``mode`` argument is provided. When ``'binary'``, returns a file-like object where its ``read`` method returns `bytes` objects. When another string, it is the name of an encoding, and the file-like object's ``read`` method will return `str` (``unicode``) objects, decoded from binary using the given encoding. Returns ------- fileobjs : iterator of file objects File objects for each of the files on the local filesystem in *datadir* matching *pattern*. Examples -------- This will retrieve the contents of the data file for the `astropy.wcs` tests:: >>> from astropy.utils.data import get_pkg_data_filenames >>> for fd in get_pkg_data_fileobjs('data/maps', 'astropy.wcs.tests', ... '*.hdr'): ... fcontents = fd.read() ... """ for fn in get_pkg_data_filenames(datadir, package=package, pattern=pattern): with get_readable_fileobj(fn, encoding=encoding) as fd: yield fd
[docs]def compute_hash(localfn): """ Computes the MD5 hash for a file. The hash for a data file is used for looking up data files in a unique fashion. This is of particular use for tests; a test may require a particular version of a particular file, in which case it can be accessed via hash to get the appropriate version. Typically, if you wish to write a test that requires a particular data file, you will want to submit that file to the astropy data servers, and use e.g. ``get_pkg_data_filename('hash/34c33b3eb0d56eb9462003af249eff28')``, but with the hash for your file in place of the hash in the example. Parameters ---------- localfn : str The path to the file for which the hash should be generated. Returns ------- hash : str The hex digest of the cryptographic hash for the contents of the ``localfn`` file. """ with open(localfn, 'rb') as f: h = hashlib.md5() block = f.read(conf.compute_hash_block_size) while block: h.update(block) block = f.read(conf.compute_hash_block_size) return h.hexdigest()
def _find_pkg_data_path(data_name, package=None): """ Look for data in the source-included data directories and return the path. """ if package is None: module = find_current_module(1, finddiff=['astropy.utils.data', 'contextlib']) if module is None: # not called from inside an astropy package. So just pass name # through return data_name if not hasattr(module, '__package__') or not module.__package__: # The __package__ attribute may be missing or set to None; see # PEP-366, also astropy issue #1256 if '.' in module.__name__: package = module.__name__.rpartition('.')[0] else: package = module.__name__ else: package = module.__package__ else: module = resolve_name(package) rootpkgname = package.partition('.')[0] rootpkg = resolve_name(rootpkgname) module_path = os.path.dirname(module.__file__) path = os.path.join(module_path, data_name) root_dir = os.path.dirname(rootpkg.__file__) if not _is_inside(path, root_dir): raise RuntimeError(f"attempted to get a local data file outside " f"of the {rootpkgname} tree.") return path def _find_hash_fn(hexdigest, pkgname='astropy'): """ Looks for a local file by hash - returns file name if found and a valid file, otherwise returns None. """ for v in cache_contents(pkgname=pkgname).values(): if compute_hash(v) == hexdigest: return v return None
[docs]def get_free_space_in_dir(path): """ Given a path to a directory, returns the amount of free space (in bytes) on that filesystem. Parameters ---------- path : str The path to a directory Returns ------- bytes : int The amount of free space on the partition that the directory is on. """ if not os.path.isdir(path): raise OSError( "Can only determine free space associated with directories, " "not files.") # Actually you can on Linux but I want to avoid code that fails # on Windows only. return shutil.disk_usage(path).free
[docs]def check_free_space_in_dir(path, size): """ Determines if a given directory has enough space to hold a file of a given size. Raises an OSError if the file would be too large. Parameters ---------- path : str The path to a directory size : int A proposed filesize (in bytes) Raises ------- OSError : There is not enough room on the filesystem """ from astropy.utils.console import human_file_size space = get_free_space_in_dir(path) if space < size: raise OSError(f"Not enough free space in {path} " f"to download a {human_file_size(size)} file")
class _ftptlswrapper(urllib.request.ftpwrapper): def init(self): self.busy = 0 self.ftp = ftplib.FTP_TLS() self.ftp.connect(self.host, self.port, self.timeout) self.ftp.login(self.user, self.passwd) self.ftp.prot_p() _target = '/'.join(self.dirs) self.ftp.cwd(_target) class _FTPTLSHandler(urllib.request.FTPHandler): def connect_ftp(self, user, passwd, host, port, dirs, timeout): return _ftptlswrapper(user, passwd, host, port, dirs, timeout, persistent=False) def _download_file_from_source(source_url, show_progress=True, timeout=None, remote_url=None, cache=False, pkgname='astropy', http_headers=None, ftp_tls=None): from astropy.utils.console import ProgressBarOrSpinner if timeout == 0: raise urllib.error.URLError( f"URL {remote_url} was supposed to be downloaded but timeout was set to 0; " f"if this is unexpected check the astropy config file for the option " f"remote_timeout") if remote_url is None: remote_url = source_url if http_headers is None: http_headers = {} if ftp_tls is None and urllib.parse.urlparse(remote_url).scheme == "ftp": try: return _download_file_from_source(source_url, show_progress=show_progress, timeout=timeout, remote_url=remote_url, cache=cache, pkgname=pkgname, http_headers=http_headers, ftp_tls=False) except urllib.error.URLError as e: # e.reason might not be a string, e.g. socket.gaierror if str(e.reason).startswith("ftp error: error_perm"): ftp_tls = True else: raise if ftp_tls: urlopener = urllib.request.build_opener(_FTPTLSHandler()) else: urlopener = urllib.request.build_opener() req = urllib.request.Request(source_url, headers=http_headers) with urlopener.open(req, timeout=timeout) as remote: info = remote.info() try: size = int(info['Content-Length']) except (KeyError, ValueError, TypeError): size = None if size is not None: check_free_space_in_dir(gettempdir(), size) if cache: dldir = _get_download_cache_loc(pkgname) check_free_space_in_dir(dldir, size) if show_progress and sys.stdout.isatty(): progress_stream = sys.stdout else: progress_stream = io.StringIO() if source_url == remote_url: dlmsg = f"Downloading {remote_url}" else: dlmsg = f"Downloading {remote_url} from {source_url}" with ProgressBarOrSpinner(size, dlmsg, file=progress_stream) as p: with NamedTemporaryFile(prefix=f"astropy-download-{os.getpid()}-", delete=False) as f: try: bytes_read = 0 block = remote.read(conf.download_block_size) while block: f.write(block) bytes_read += len(block) p.update(bytes_read) block = remote.read(conf.download_block_size) if size is not None and bytes_read > size: raise urllib.error.URLError( f"File was supposed to be {size} bytes but " f"server provides more, at least {bytes_read} " f"bytes. Download failed.") if size is not None and bytes_read < size: raise urllib.error.ContentTooShortError( f"File was supposed to be {size} bytes but we " f"only got {bytes_read} bytes. Download failed.", content=None) except BaseException: if os.path.exists(f.name): try: os.remove(f.name) except OSError: pass raise return f.name
[docs]def download_file(remote_url, cache=False, show_progress=True, timeout=None, sources=None, pkgname='astropy', http_headers=None): """Downloads a URL and optionally caches the result. It returns the filename of a file containing the URL's contents. If ``cache=True`` and the file is present in the cache, just returns the filename; if the file had to be downloaded, add it to the cache. If ``cache="update"`` always download and add it to the cache. The cache is effectively a dictionary mapping URLs to files; by default the file contains the contents of the URL that is its key, but in practice these can be obtained from a mirror (using ``sources``) or imported from the local filesystem (using `~import_file_to_cache` or `~import_download_cache`). Regardless, each file is regarded as representing the contents of a particular URL, and this URL should be used to look them up or otherwise manipulate them. The files in the cache directory are named according to a cryptographic hash of their URLs (currently MD5, so hackers can cause collisions). The modification times on these files normally indicate when they were last downloaded from the Internet. Parameters ---------- remote_url : str The URL of the file to download cache : bool or "update", optional Whether to cache the contents of remote URLs. If "update", always download the remote URL in case there is a new version and store the result in the cache. show_progress : bool, optional Whether to display a progress bar during the download (default is `True`). Regardless of this setting, the progress bar is only displayed when outputting to a terminal. timeout : float, optional The timeout, in seconds. Otherwise, use `astropy.utils.data.Conf.remote_timeout`. Set this to zero to prevent any attempt to download anything. sources : list of str, optional If provided, a list of URLs to try to obtain the file from. The result will be stored under the original URL. The original URL will *not* be tried unless it is in this list; this is to prevent long waits for a primary server that is known to be inaccessible at the moment. If an empty list is passed, then ``download_file`` will not attempt to connect to the Internet, that is, if the file is not in the cache a KeyError will be raised. pkgname : `str`, optional The package name to use to locate the download cache. i.e. for ``pkgname='astropy'`` the default cache location is ``~/.astropy/cache``. http_headers : dict or None HTTP request headers to pass into ``urlopen`` if needed. (These headers are ignored if the protocol for the ``name_or_obj``/``sources`` entry is not a remote HTTP URL.) In the default case (None), the headers are ``User-Agent: some_value`` and ``Accept: */*``, where ``some_value`` is set by ``astropy.utils.data.conf.default_http_user_agent``. Returns ------- local_path : str Returns the local path that the file was download to. Raises ------ urllib.error.URLError Whenever there's a problem getting the remote file. KeyError When a file was requested from the cache but is missing and no sources were provided to obtain it from the Internet. Notes ----- Because this function returns a filename, another process could run `clear_download_cache` before you actually open the file, leaving you with a filename that no longer points to a usable file. """ if timeout is None: timeout = conf.remote_timeout if sources is None: sources = [remote_url] if http_headers is None: http_headers = {'User-Agent': conf.default_http_user_agent, 'Accept': '*/*'} missing_cache = "" url_key = remote_url if cache: try: dldir = _get_download_cache_loc(pkgname) except OSError as e: cache = False missing_cache = ( f"Cache directory cannot be read or created ({e}), " f"providing data in temporary file instead." ) else: if cache == "update": pass elif isinstance(cache, str): raise ValueError(f"Cache value '{cache}' was requested but " f"'update' is the only recognized string; " f"otherwise use a boolean") else: filename = os.path.join(dldir, _url_to_dirname(url_key), "contents") if os.path.exists(filename): return os.path.abspath(filename) errors = {} for source_url in sources: try: f_name = _download_file_from_source( source_url, timeout=timeout, show_progress=show_progress, cache=cache, remote_url=remote_url, pkgname=pkgname, http_headers=http_headers) # Success! break except urllib.error.URLError as e: # errno 8 is from SSL "EOF occurred in violation of protocol" if (hasattr(e, 'reason') and hasattr(e.reason, 'errno') and e.reason.errno == 8): e.reason.strerror = (e.reason.strerror + '. requested URL: ' + remote_url) e.reason.args = (e.reason.errno, e.reason.strerror) errors[source_url] = e except socket.timeout as e: # this isn't supposed to happen, but occasionally a socket.timeout # gets through. It's supposed to be caught in urllib and raised # in this way, but for some reason in mysterious circumstances it # doesn't (or didn't in python2?). So we'll just re-raise it here # instead. errors[source_url] = e else: # No success if not sources: raise KeyError( f"No sources listed and file {remote_url} not in cache! " f"Please include primary URL in sources if you want it to be " f"included as a valid source.") elif len(sources) == 1: raise errors[sources[0]] else: raise urllib.error.URLError( f"Unable to open any source! Exceptions were {errors}") \ from errors[sources[0]] if cache: try: return import_file_to_cache(url_key, f_name, remove_original=True, replace=(cache == 'update'), pkgname=pkgname) except PermissionError as e: # Cache is readonly, we can't update it missing_cache = ( f"Cache directory appears to be read-only ({e}), unable to import " f"downloaded file, providing data in temporary file {f_name} " f"instead.") # FIXME: other kinds of cache problem can occur? if missing_cache: warn(CacheMissingWarning(missing_cache, f_name)) if conf.delete_temporary_downloads_at_exit: global _tempfilestodel _tempfilestodel.append(f_name) return os.path.abspath(f_name)
[docs]def is_url_in_cache(url_key, pkgname='astropy'): """Check if a download for ``url_key`` is in the cache. The provided ``url_key`` will be the name used in the cache. The contents may have been downloaded from this URL or from a mirror or they may have been provided by the user. See `~download_file` for details. Parameters ---------- url_key : str The URL retrieved pkgname : `str`, optional The package name to use to locate the download cache. i.e. for ``pkgname='astropy'`` the default cache location is ``~/.astropy/cache``. Returns ------- in_cache : bool `True` if a download for ``url_key`` is in the cache, `False` if not or if the cache does not exist at all. See Also -------- cache_contents : obtain a dictionary listing everything in the cache """ try: dldir = _get_download_cache_loc(pkgname) except OSError: return False filename = os.path.join(dldir, _url_to_dirname(url_key), "contents") return os.path.exists(filename)
[docs]def cache_total_size(pkgname='astropy'): """Return the total size in bytes of all files in the cache.""" size = 0 dldir = _get_download_cache_loc(pkgname=pkgname) for root, dirs, files in os.walk(dldir): size += sum(os.path.getsize(os.path.join(root, name)) for name in files) return size
def _do_download_files_in_parallel(kwargs): with astropy.config.paths.set_temp_config(kwargs.pop("temp_config")): with astropy.config.paths.set_temp_cache(kwargs.pop("temp_cache")): return download_file(**kwargs)
[docs]def download_files_in_parallel(urls, cache="update", show_progress=True, timeout=None, sources=None, multiprocessing_start_method=None, pkgname='astropy'): """Download multiple files in parallel from the given URLs. Blocks until all files have downloaded. The result is a list of local file paths corresponding to the given urls. The results will be stored in the cache under the values in ``urls`` even if they are obtained from some other location via ``sources``. See `~download_file` for details. Parameters ---------- urls : list of str The URLs to retrieve. cache : bool or "update", optional Whether to use the cache (default is `True`). If "update", always download the remote URLs to see if new data is available and store the result in cache. .. versionchanged:: 4.0 The default was changed to ``"update"`` and setting it to ``False`` will print a Warning and set it to ``"update"`` again, because the function will not work properly without cache. Using ``True`` will work as expected. .. versionchanged:: 3.0 The default was changed to ``True`` and setting it to ``False`` will print a Warning and set it to ``True`` again, because the function will not work properly without cache. show_progress : bool, optional Whether to display a progress bar during the download (default is `True`) timeout : float, optional Timeout for each individual requests in seconds (default is the configurable `astropy.utils.data.Conf.remote_timeout`). Set this to zero to prevent any attempt to download anything. sources : dict, optional If provided, for each URL a list of URLs to try to obtain the file from. The result will be stored under the original URL. For any URL in this dictionary, the original URL will *not* be tried unless it is in this list; this is to prevent long waits for a primary server that is known to be inaccessible at the moment. multiprocessing_start_method : str, optional Useful primarily for testing; if in doubt leave it as the default. When using multiprocessing, certain anomalies occur when starting processes with the "spawn" method (the only option on Windows); other anomalies occur with the "fork" method (the default on Linux). pkgname : `str`, optional The package name to use to locate the download cache. i.e. for ``pkgname='astropy'`` the default cache location is ``~/.astropy/cache``. Returns ------- paths : list of str The local file paths corresponding to the downloaded URLs. Notes ----- If a URL is unreachable, the downloading will grind to a halt and the exception will propagate upward, but an unpredictable number of files will have been successfully downloaded and will remain in the cache. """ from .console import ProgressBar if timeout is None: timeout = conf.remote_timeout if sources is None: sources = {} if not cache: # See issue #6662, on windows won't work because the files are removed # again before they can be used. On *NIX systems it will behave as if # cache was set to True because multiprocessing cannot insert the items # in the list of to-be-removed files. This could be fixed, but really, # just use the cache, with update_cache if appropriate. warn('Disabling the cache does not work because of multiprocessing, ' 'it will be set to ``"update"``. You may need to manually remove ' 'the cached files with clear_download_cache() afterwards.', AstropyWarning) cache = "update" if show_progress: progress = sys.stdout else: progress = io.BytesIO() # Combine duplicate URLs combined_urls = list(set(urls)) combined_paths = ProgressBar.map( _do_download_files_in_parallel, [dict(remote_url=u, cache=cache, show_progress=False, timeout=timeout, sources=sources.get(u, None), pkgname=pkgname, temp_cache=astropy.config.paths.set_temp_cache._temp_path, temp_config=astropy.config.paths.set_temp_config._temp_path) for u in combined_urls], file=progress, multiprocess=True, multiprocessing_start_method=multiprocessing_start_method, ) paths = [] for url in urls: paths.append(combined_paths[combined_urls.index(url)]) return paths
# This is used by download_file and _deltemps to determine the files to delete # when the interpreter exits _tempfilestodel = [] @atexit.register def _deltemps(): global _tempfilestodel if _tempfilestodel is not None: while len(_tempfilestodel) > 0: fn = _tempfilestodel.pop() if os.path.isfile(fn): try: os.remove(fn) except OSError: # oh well we tried # could be held open by some process, on Windows pass elif os.path.isdir(fn): try: shutil.rmtree(fn) except OSError: # couldn't get rid of it, sorry # could be held open by some process, on Windows pass
[docs]def clear_download_cache(hashorurl=None, pkgname='astropy'): """Clears the data file cache by deleting the local file(s). If a URL is provided, it will be the name used in the cache. The contents may have been downloaded from this URL or from a mirror or they may have been provided by the user. See `~download_file` for details. For the purposes of this function, a file can also be identified by a hash of its contents or by the filename under which the data is stored (as returned by `~download_file`, for example). Parameters ---------- hashorurl : str or None If None, the whole cache is cleared. Otherwise, specify a hash for the cached file that is supposed to be deleted, the full path to a file in the cache that should be deleted, or a URL that should be removed from the cache if present. pkgname : `str`, optional The package name to use to locate the download cache. i.e. for ``pkgname='astropy'`` the default cache location is ``~/.astropy/cache``. """ try: dldir = _get_download_cache_loc(pkgname) except OSError as e: # Problem arose when trying to open the cache # Just a warning, though msg = 'Not clearing data cache - cache inaccessible due to ' estr = '' if len(e.args) < 1 else (': ' + str(e)) warn(CacheMissingWarning(msg + e.__class__.__name__ + estr)) return try: if hashorurl is None: # Optional: delete old incompatible caches too _rmtree(dldir) elif _is_url(hashorurl): filepath = os.path.join(dldir, _url_to_dirname(hashorurl)) _rmtree(filepath) else: # Not a URL, it should be either a filename or a hash filepath = os.path.join(dldir, hashorurl) rp = os.path.relpath(filepath, dldir) if rp.startswith(".."): raise RuntimeError( f"attempted to use clear_download_cache on the path " f"{filepath} outside the data cache directory {dldir}") d, f = os.path.split(rp) if d and f in ["contents", "url"]: # It's a filename not the hash of a URL # so we want to zap the directory containing the # files "url" and "contents" filepath = os.path.join(dldir, d) if os.path.exists(filepath): _rmtree(filepath) elif (len(hashorurl) == 2*hashlib.md5().digest_size and re.match(r"[0-9a-f]+", hashorurl)): # It's the hash of some file contents, we have to find the right file filename = _find_hash_fn(hashorurl) if filename is not None: clear_download_cache(filename) except OSError as e: msg = 'Not clearing data from cache - problem arose ' estr = '' if len(e.args) < 1 else (': ' + str(e)) warn(CacheMissingWarning(msg + e.__class__.__name__ + estr))
def _get_download_cache_loc(pkgname='astropy'): """Finds the path to the cache directory and makes them if they don't exist. Parameters ---------- pkgname : `str`, optional The package name to use to locate the download cache. i.e. for ``pkgname='astropy'`` the default cache location is ``~/.astropy/cache``. Returns ------- datadir : str The path to the data cache directory. """ try: datadir = os.path.join(astropy.config.paths.get_cache_dir(pkgname), 'download', 'url') if not os.path.exists(datadir): try: os.makedirs(datadir) except OSError: if not os.path.exists(datadir): raise elif not os.path.isdir(datadir): raise OSError(f'Data cache directory {datadir} is not a directory') return datadir except OSError as e: msg = 'Remote data cache could not be accessed due to ' estr = '' if len(e.args) < 1 else (': ' + str(e)) warn(CacheMissingWarning(msg + e.__class__.__name__ + estr)) raise def _url_to_dirname(url): if not _is_url(url): raise ValueError(f"Malformed URL: '{url}'") # Make domain names case-insensitive # Also makes the http:// case-insensitive urlobj = list(urllib.parse.urlsplit(url)) urlobj[1] = urlobj[1].lower() if urlobj[0].lower() in ['http', 'https'] and urlobj[1] and urlobj[2] == '': urlobj[2] = '/' url_c = urllib.parse.urlunsplit(urlobj) return hashlib.md5(url_c.encode("utf-8")).hexdigest() class ReadOnlyDict(dict): def __setitem__(self, key, value): raise TypeError("This object is read-only.") _NOTHING = ReadOnlyDict({}) class CacheDamaged(ValueError): """Record the URL or file that was a problem. Using clear_download_cache on the .bad_file or .bad_url attribute, whichever is not None, should resolve this particular problem. """ def __init__(self, *args, bad_urls=None, bad_files=None, **kwargs): super().__init__(*args, **kwargs) self.bad_urls = bad_urls if bad_urls is not None else [] self.bad_files = bad_files if bad_files is not None else []
[docs]def check_download_cache(check_hashes=False, pkgname='astropy'): """Do a consistency check on the cache. Because the cache is shared by all versions of astropy in all virtualenvs run by your user, possibly concurrently, it could accumulate problems. This could lead to hard-to-debug problems or wasted space. This function detects a number of incorrect conditions, including nonexistent files that are indexed, files that are indexed but in the wrong place, and, if you request it, files whose content does not match the hash that is indexed. This function also returns a list of non-indexed files. A few will be associated with the shelve object; their exact names depend on the backend used but will probably be based on ``urlmap``. The presence of other files probably indicates that something has gone wrong and inaccessible files have accumulated in the cache. These can be removed with `clear_download_cache`, either passing the filename returned here, or with no arguments to empty the entire cache and return it to a reasonable, if empty, state. Parameters ---------- check_hashes : boolean, optional Deprecated; does nothing. pkgname : `str`, optional The package name to use to locate the download cache. i.e. for ``pkgname='astropy'`` the default cache location is ``~/.astropy/cache``. Returns ------- strays : set Deprecated. The empty set. Raises ------ CacheDamaged To indicate a problem with the cache contents; the exception contains a ``.bad_files`` attribute containing a set of filenames to allow the user to use `clear_download_cache` to remove the offending items. OSError, RuntimeError To indicate some problem with the cache structure. This may need a full `clear_download_cache` to resolve, or may indicate some kind of misconfiguration. """ bad_files = set() messages = set() dldir = _get_download_cache_loc(pkgname=pkgname) with os.scandir(dldir) as it: for entry in it: f = os.path.abspath(os.path.join(dldir, entry.name)) if entry.name.startswith("rmtree-"): if f not in _tempfilestodel: bad_files.add(f) messages.add(f"Cache entry {entry.name} not scheduled for deletion") elif entry.is_dir(): for sf in os.listdir(f): if sf in ['url', 'contents']: continue sf = os.path.join(f, sf) bad_files.add(sf) messages.add(f"Unexpected file f{sf}") urlf = os.path.join(f, "url") url = None if not os.path.isfile(urlf): bad_files.add(urlf) messages.add(f"Problem with URL file f{urlf}") else: url = get_file_contents(urlf, encoding="utf-8") if not _is_url(url): bad_files.add(f) messages.add(f"Malformed URL: {url}") else: hashname = _url_to_dirname(url) if entry.name != hashname: bad_files.add(f) messages.add(f"URL hashes to {hashname} but is stored in {entry.name}") if not os.path.isfile(os.path.join(f, "contents")): bad_files.add(f) if url is None: messages.add(f"Hash {entry.name} is missing contents") else: messages.add(f"URL {url} with hash {entry.name} is missing contents") else: bad_files.add(f) messages.add(f"Left-over non-directory {f} in cache") if bad_files: raise CacheDamaged("\n".join(messages), bad_files=bad_files) return set()
@contextlib.contextmanager def _SafeTemporaryDirectory(suffix=None, prefix=None, dir=None): """Temporary directory context manager This will not raise an exception if the temporary directory goes away before it's supposed to be deleted. Specifically, what is deleted will be the directory *name* produced; if no such directory exists, no exception will be raised. It would be safer to delete it only if it's really the same directory - checked by file descriptor - and if it's still called the same thing. But that opens a platform-specific can of worms. It would also be more robust to use ExitStack and TemporaryDirectory, which is more aggressive about removing readonly things. """ d = mkdtemp(suffix=suffix, prefix=prefix, dir=dir) try: yield d finally: try: shutil.rmtree(d) except OSError: pass def _rmtree(path, replace=None): """More-atomic rmtree. Ignores missing directory.""" with TemporaryDirectory(prefix="rmtree-", dir=os.path.dirname(os.path.abspath(path))) as d: try: os.rename(path, os.path.join(d, "to-zap")) except FileNotFoundError: pass except PermissionError: warn(CacheMissingWarning( f"Unable to remove directory {path} because a file in it " f"is in use and you are on Windows", path)) raise if replace is not None: try: os.rename(replace, path) except FileExistsError: # already there, fine pass except OSError as e: if e.errno == errno.ENOTEMPTY: # already there, fine pass else: raise
[docs]def import_file_to_cache(url_key, filename, hexdigest=None, remove_original=False, pkgname='astropy', *, replace=True): """Import the on-disk file specified by filename to the cache. The provided ``url_key`` will be the name used in the cache. The file should contain the contents of this URL, at least notionally (the URL may be temporarily or permanently unavailable). It is using ``url_key`` that users will request these contents from the cache. See `~download_file` for details. If ``url_key`` already exists in the cache, it will be updated to point to these imported contents, and its old contents will be deleted from the cache. Parameters ---------- url_key : str The key to index the file under. This should probably be the URL where the file was located, though if you obtained it from a mirror you should use the URL of the primary location. filename : str The file whose contents you want to import. hexdigest : ignored Deprecated, has no effect. remove_original : bool Whether to remove the original file (``filename``) once import is complete. pkgname : `str`, optional The package name to use to locate the download cache. i.e. for ``pkgname='astropy'`` the default cache location is ``~/.astropy/cache``. replace : boolean, optional Whether or not to replace an existing object in the cache, if one exists. If replacement is not requested but the object exists, silently pass. """ cache_dir = _get_download_cache_loc(pkgname=pkgname) cache_dirname = _url_to_dirname(url_key) local_dirname = os.path.join(cache_dir, cache_dirname) local_filename = os.path.join(local_dirname, "contents") with _SafeTemporaryDirectory(prefix="temp_dir", dir=cache_dir) as temp_dir: temp_filename = os.path.join(temp_dir, "contents") # Make sure we're on the same filesystem # This will raise an exception if the url_key doesn't turn into a valid filename shutil.copy(filename, temp_filename) with open(os.path.join(temp_dir, "url"), "wt", encoding="utf-8") as f: f.write(url_key) if replace: _rmtree(local_dirname, replace=temp_dir) else: try: os.rename(temp_dir, local_dirname) except FileExistsError: # already there, fine pass except OSError as e: if e.errno == errno.ENOTEMPTY: # already there, fine pass else: raise if remove_original: os.remove(filename) return os.path.abspath(local_filename)
[docs]def get_cached_urls(pkgname='astropy'): """ Get the list of URLs in the cache. Especially useful for looking up what files are stored in your cache when you don't have internet access. The listed URLs are the keys programs should use to access the file contents, but those contents may have actually been obtained from a mirror. See `~download_file` for details. Parameters ---------- pkgname : `str`, optional The package name to use to locate the download cache. i.e. for ``pkgname='astropy'`` the default cache location is ``~/.astropy/cache``. Returns ------- cached_urls : list List of cached URLs. See Also -------- cache_contents : obtain a dictionary listing everything in the cache """ return sorted(cache_contents(pkgname=pkgname).keys())
[docs]def cache_contents(pkgname='astropy'): """Obtain a dict mapping cached URLs to filenames. This dictionary is a read-only snapshot of the state of the cache when this function was called. If other processes are actively working with the cache, it is possible for them to delete files that are listed in this dictionary. Use with some caution if you are working on a system that is busy with many running astropy processes, although the same issues apply to most functions in this module. """ r = {} try: dldir = _get_download_cache_loc(pkgname=pkgname) except OSError: return _NOTHING with os.scandir(dldir) as it: for entry in it: if entry.is_dir: url = get_file_contents(os.path.join(dldir, entry.name, "url"), encoding="utf-8") r[url] = os.path.abspath(os.path.join(dldir, entry.name, "contents")) return ReadOnlyDict(r)
[docs]def export_download_cache(filename_or_obj, urls=None, overwrite=False, pkgname='astropy'): """Exports the cache contents as a ZIP file. Parameters ---------- filename_or_obj : str or file-like Where to put the created ZIP file. Must be something the zipfile module can write to. urls : iterable of str or None The URLs to include in the exported cache. The default is all URLs currently in the cache. If a URL is included in this list but is not currently in the cache, a KeyError will be raised. To ensure that all are in the cache use `~download_file` or `~download_files_in_parallel`. overwrite : bool, optional If filename_or_obj is a filename that exists, it will only be overwritten if this is True. pkgname : `str`, optional The package name to use to locate the download cache. i.e. for ``pkgname='astropy'`` the default cache location is ``~/.astropy/cache``. See Also -------- import_download_cache : import the contents of such a ZIP file import_file_to_cache : import a single file directly """ if urls is None: urls = get_cached_urls(pkgname) with zipfile.ZipFile(filename_or_obj, 'w' if overwrite else 'x') as z: for u in urls: fn = download_file(u, cache=True, sources=[], pkgname=pkgname) # Do not use os.path.join because ZIP files want # "/" on all platforms z_fn = urllib.parse.quote(u, safe="") z.write(fn, z_fn)
[docs]def import_download_cache(filename_or_obj, urls=None, update_cache=False, pkgname='astropy'): """Imports the contents of a ZIP file into the cache. Each member of the ZIP file should be named by a quoted version of the URL whose contents it stores. These names are decoded with :func:`~urllib.parse.unquote`. Parameters ---------- filename_or_obj : str or file-like Where the stored ZIP file is. Must be something the :mod:`~zipfile` module can read from. urls : set of str or list of str or None The URLs to import from the ZIP file. The default is all URLs in the file. update_cache : bool, optional If True, any entry in the ZIP file will overwrite the value in the cache; if False, leave untouched any entry already in the cache. pkgname : `str`, optional The package name to use to locate the download cache. i.e. for ``pkgname='astropy'`` the default cache location is ``~/.astropy/cache``. See Also -------- export_download_cache : export the contents the cache to of such a ZIP file import_file_to_cache : import a single file directly """ with zipfile.ZipFile(filename_or_obj, 'r') as z, TemporaryDirectory() as d: for i, zf in enumerate(z.infolist()): url = urllib.parse.unquote(zf.filename) # FIXME(aarchiba): do we want some kind of validation on this URL? # urllib.parse might do something sensible...but what URLs might # they have? # is_url in this file is probably a good check, not just here # but throughout this file. if urls is not None and url not in urls: continue if not update_cache and is_url_in_cache(url, pkgname=pkgname): continue f_temp_name = os.path.join(d, str(i)) with z.open(zf) as f_zip, open(f_temp_name, "wb") as f_temp: block = f_zip.read(conf.download_block_size) while block: f_temp.write(block) block = f_zip.read(conf.download_block_size) import_file_to_cache(url, f_temp_name, remove_original=True, pkgname=pkgname)