def _check_hash_stamp(fpath,
hash_prefix,
hasher,
verbose,
needs_download=False):
stamp_fpath = fpath + '.hash'
# Force a re-download if the hash file does not exist or it does
# not match the expected hash
if exists(stamp_fpath):
with open(stamp_fpath, 'r') as file:
hashstr = file.read()
if not hashstr.startswith(hash_prefix):
if verbose: # pragma: nobranch
print('invalid hash value (expected "{}", got "{}")'.format(
hash_prefix, hashstr))
needs_download = True
elif exists(fpath):
# If the file exists, but the hash doesnt exist, simply compute the
# hash of the existing file instead of redownloading it.
# Redownload if this fails.
from ubelt import util_hash
hashstr = util_hash.hash_file(fpath, hasher=hasher)
if hashstr.startswith(hash_prefix):
# Write the missing stamp file if it matches
with open(stamp_fpath, 'w') as file:
file.write(hash_prefix)
else:
if verbose: # pragma: nobranch
print('invalid hash value (expected "{}", got "{}")'.format(
hash_prefix, hashstr))
needs_download = True
else:
needs_download = True
return stamp_fpath, needs_download
def _product_file_hash(self, product=None):
"""
Get the hash of the each product file
"""
if self.hasher is None:
return None
else:
products = self._rectify_products(product)
product_file_hash = [
util_hash.hash_file(p, hasher=self.hasher, base='hex')
for p in products
]
return product_file_hash
def grabdata(url, fpath=None, dpath=None, fname=None, redo=False,
verbose=1, appname=None, hash_prefix=None, hasher='sha512',
**download_kw):
"""
Downloads a file, caches it, and returns its local path.
Args:
url (str): url to the file to download
fpath (PathLike): The full path to download the file to. If
unspecified, the arguments `dpath` and `fname` are used to
determine this.
dpath (PathLike): where to download the file. If unspecified `appname`
is used to determine this. Mutually exclusive with fpath.
fname (str): What to name the downloaded file. Defaults to the url
basename. Mutually exclusive with fpath.
redo (bool): if True forces redownload of the file (default = False)
verbose (bool): verbosity flag (default = True)
appname (str): set dpath to `ub.get_app_cache_dir(appname)`.
Mutually exclusive with dpath and fpath.
hash_prefix (None or str):
If specified, grabdata verifies that this matches the hash of the
file, and then saves the hash in a adjacent file to certify that
the download was successful. Defaults to None.
hasher (str or Hasher):
If hash_prefix is specified, this indicates the hashing
algorithm to apply to the file. Defaults to sha512.
**download_kw: additional kwargs to pass to ub.download
Returns:
PathLike: fpath - file path string
Example:
>>> # xdoctest: +REQUIRES(--network)
>>> import ubelt as ub
>>> url = 'http://i.imgur.com/rqwaDag.png'
>>> fpath = ub.grabdata(url, fname='mario.png')
>>> result = basename(fpath)
>>> print(result)
mario.png
Example:
>>> # xdoctest: +REQUIRES(--network)
>>> import ubelt as ub
>>> fname = 'foo.bar'
>>> url = 'http://i.imgur.com/rqwaDag.png'
>>> prefix1 = '944389a39dfb8fa9'
>>> fpath = ub.grabdata(url, fname=fname, hash_prefix=prefix1)
>>> stamp_fpath = fpath + '.hash'
>>> assert open(stamp_fpath, 'r').read() == prefix1
>>> # Check that the download doesn't happen again
>>> fpath = ub.grabdata(url, fname=fname, hash_prefix=prefix1)
>>> # todo: check file timestamps have not changed
>>> #
>>> # Check redo works with hash
>>> fpath = ub.grabdata(url, fname=fname, hash_prefix=prefix1, redo=True)
>>> # todo: check file timestamps have changed
>>> #
>>> # Check that a redownload occurs when the stamp is changed
>>> open(stamp_fpath, 'w').write('corrupt-stamp')
>>> fpath = ub.grabdata(url, fname=fname, hash_prefix=prefix1)
>>> assert open(stamp_fpath, 'r').read() == prefix1
>>> #
>>> # Check that a redownload occurs when the stamp is removed
>>> ub.delete(stamp_fpath)
>>> open(fpath, 'w').write('corrupt-data')
>>> assert not ub.hash_file(fpath, base='hex').startswith(prefix1)
>>> fpath = ub.grabdata(url, fname=fname, hash_prefix=prefix1)
>>> assert ub.hash_file(fpath, base='hex').startswith(prefix1)
>>> #
>>> # Check that requesting new data causes redownload
>>> url2 = 'https://data.kitware.com/api/v1/item/5b4039308d777f2e6225994c/download'
>>> prefix2 = 'c98a46cb31205cf'
>>> fpath = ub.grabdata(url2, fname=fname, hash_prefix=prefix2)
>>> assert open(stamp_fpath, 'r').read() == prefix2
"""
if appname and dpath:
raise ValueError('Cannot specify appname with dpath')
if fpath and (dpath or fname or appname):
raise ValueError('Cannot specify fpath with dpath or fname')
if fpath is None:
if dpath is None:
appname = appname or 'ubelt'
dpath = util_platform.ensure_app_cache_dir(appname)
if fname is None:
fname = basename(url)
fpath = join(dpath, fname)
# note that needs_download is never set to false after it becomes true
# this is the key to working through the logic of the following checks
needs_download = redo
if not exists(fpath):
# always download if we are missing the file
needs_download = True
if hash_prefix:
stamp_fpath = fpath + '.hash'
# Force a re-download if the hash file does not exist or it does
# not match the expected hash
if exists(stamp_fpath):
with open(stamp_fpath, 'r') as file:
hashstr = file.read()
if not hashstr.startswith(hash_prefix):
if verbose: # pragma: nobranch
print('invalid hash value (expected "{}", got "{}")'.format(
hash_prefix, hashstr))
needs_download = True
elif exists(fpath):
# If the file exists, but the hash doesnt exist, simply compute the
# hash of the existing file instead of redownloading it.
# Redownload if this fails.
from ubelt import util_hash
hashstr = util_hash.hash_file(fpath, hasher=hasher)
if hashstr.startswith(hash_prefix):
# Write the missing stamp file if it matches
with open(stamp_fpath, 'w') as file:
file.write(hash_prefix)
else:
if verbose: # pragma: nobranch
print('invalid hash value (expected "{}", got "{}")'.format(
hash_prefix, hashstr))
needs_download = True
else:
needs_download = True
if needs_download:
fpath = download(url, fpath, verbose=verbose,
hash_prefix=hash_prefix, hasher=hasher,
**download_kw)
if hash_prefix:
# If the file successfully downloaded then the hashes match.
# write out the expected prefix so we can check it later
with open(stamp_fpath, 'w') as file:
file.write(hash_prefix)
else:
if verbose >= 2:
print('Already have file %s' % fpath)
return fpath
