def put_file_from_fobj(self, src, desc=""):
"""Store a file in the storage.
If it's already (for some reason...) in the cache send that
copy to the backend. Otherwise store it in the file-system
cache first.
The file is obtained from a file-object. Other interfaces are
available as `put_file_content', `put_file_from_path'.
src (fileobj): a readable binary file-like object from which
to read the contents of the file.
desc (unicode): the (optional) description to associate to the
file.
return (unicode): the digest of the stored file.
"""
logger.debug("Reading input file to store on the database.")
# Unfortunately, we have to read the whole file-obj to compute
# the digest but we take that chance to save it to a temporary
# path so that we then just need to move it. Hoping that both
# locations will be on the same filesystem, that should be way
# faster than reading the whole file-obj again (as it could be
# compressed or require network communication).
# XXX We're *almost* reimplementing copyfileobj.
with tempfile.NamedTemporaryFile('wb', delete=False,
dir=config.temp_dir) as dst:
hasher = hashlib.sha1()
buf = src.read(self.CHUNK_SIZE)
while len(buf) > 0:
hasher.update(buf)
while len(buf) > 0:
written = dst.write(buf)
# Cooperative yield.
gevent.sleep(0)
if written is None:
break
buf = buf[written:]
buf = src.read(self.CHUNK_SIZE)
digest = hasher.hexdigest().decode("ascii")
dst.flush()
logger.debug("File has digest %s." % digest)
cache_file_path = os.path.join(self.file_dir, digest)
if not os.path.exists(cache_file_path):
move(dst.name, cache_file_path)
else:
os.unlink(dst.name)
# Store the file in the backend. We do that even if the file
# was already in the cache (that is, we ignore the check above)
# because there's a (small) chance that the file got removed
# from the backend but somehow remained in the cache.
self.save(digest, desc)
return digest
def put_file_from_fobj(self, src, desc=""):
"""Store a file in the storage.
If it's already (for some reason...) in the cache send that
copy to the backend. Otherwise store it in the file-system
cache first.
The file is obtained from a file-object. Other interfaces are
available as `put_file_content', `put_file_from_path'.
src (fileobj): a readable binary file-like object from which
to read the contents of the file.
desc (unicode): the (optional) description to associate to the
file.
return (unicode): the digest of the stored file.
"""
logger.debug("Reading input file to store on the database.")
# Unfortunately, we have to read the whole file-obj to compute
# the digest but we take that chance to save it to a temporary
# path so that we then just need to move it. Hoping that both
# locations will be on the same filesystem, that should be way
# faster than reading the whole file-obj again (as it could be
# compressed or require network communication).
# XXX We're *almost* reimplementing copyfileobj.
with tempfile.NamedTemporaryFile('wb', delete=False,
dir=self.temp_dir) as dst:
hasher = hashlib.sha1()
buf = src.read(self.CHUNK_SIZE)
while len(buf) > 0:
hasher.update(buf)
while len(buf) > 0:
written = dst.write(buf)
# Cooperative yield.
gevent.sleep(0)
if written is None:
break
buf = buf[written:]
buf = src.read(self.CHUNK_SIZE)
digest = bin_to_hex(hasher.digest())
dst.flush()
logger.debug("File has digest %s.", digest)
cache_file_path = os.path.join(self.file_dir, digest)
if not os.path.exists(cache_file_path):
move(dst.name, cache_file_path)
else:
os.unlink(dst.name)
# Store the file in the backend. We do that even if the file
# was already in the cache (that is, we ignore the check above)
# because there's a (small) chance that the file got removed
# from the backend but somehow remained in the cache.
self.save(digest, desc)
return digest
def put_file(self, description="", binary_data=None,
file_obj=None, path=None):
"""Put a file in the storage, and keep a copy locally. The
caller has to provide exactly one among binary_data, file_obj
and path.
description (string): a human-readable description of the
content.
binary_data (string): the content of the file to send.
file_obj (file): the file-like object to send.
path (string): the file to send.
"""
temp_fd, temp_path = tempfile.mkstemp(dir=self.tmp_dir)
os.close(temp_fd)
# Input checking
if [binary_data, file_obj, path].count(None) != 2:
error_string = "No content (or too many) specified in put_file."
logger.error(error_string)
raise ValueError(error_string)
logger.debug("Reading input file to store on the database.")
# Copy the file content, whatever forms it arrives, into the
# temporary file
if path is not None:
copy(path, temp_path)
elif binary_data is not None:
with open(temp_path, 'wb') as temp_file:
temp_file.write(binary_data)
else: # file_obj is not None.
with open(temp_path, 'wb') as temp_file:
copyfileobj(file_obj, temp_file)
hasher = hashlib.sha1()
# Calculate the file SHA1 digest
with open(temp_path, 'rb') as temp_file:
buf = temp_file.read(self.CHUNK_SIZE)
while buf != '':
hasher.update(buf)
buf = temp_file.read(self.CHUNK_SIZE)
digest = hasher.hexdigest()
logger.debug("File has digest %s." % digest)
self.backend.put_file(digest, temp_path, description=description)
# Move the temporary file in the cache
move(temp_path,
os.path.join(self.obj_dir, digest))
return digest
def get_file(self, digest, path=None, file_obj=None,
string=False, temp_path=False, temp_file_obj=False):
"""Get a file from the storage, possibly using the cache if
the file is available there.
digest (string): the sha1 sum of the file.
path (string): a path where to save the file.
file_obj (file): a handler where to save the file (that is not
closed at return).
string (bool): True to return content as a string.
temp_path (bool): True to return path of a temporary file with
that content. The file is reserved to the
caller, who has the duty to unlink it.
temp_file-obj (bool): True to return a file object opened to a
temporary file with that content. The
file is reserved to the caller. Use this
method only for debugging purpose, as it
leave a file lying in the temporary
directory of FileCacher.
"""
if [string, temp_path, temp_file_obj].count(True) > 1:
raise ValueError("Ask for at most one amongst content, "
"temp path and temp file obj.")
cache_path = os.path.join(self.obj_dir, digest)
cache_exists = os.path.exists(cache_path)
logger.debug("Getting file %s." % (digest))
if not cache_exists:
logger.debug("File %s not in cache, downloading "
"from database." % digest)
# Receives the file from the database
temp_file, temp_filename = tempfile.mkstemp(dir=self.tmp_dir)
temp_file = os.fdopen(temp_file, "wb")
self.backend.get_file(digest, temp_filename)
# And move it in the cache. Warning: this is not atomic if
# the temp and the cache dir are on different filesystems.
move(temp_filename, cache_path)
logger.debug("File %s downloaded." % digest)
# Saving to path
if path is not None:
copy(cache_path, path)
# Saving to file object
if file_obj is not None:
with open(cache_path, "rb") as file_:
copyfileobj(file_, file_obj)
# Returning string?
if string:
with open(cache_path, "rb") as cache_file:
return cache_file.read()
# Returning temporary file?
elif temp_path:
temp_file, temp_filename = tempfile.mkstemp(dir=self.tmp_dir)
os.close(temp_file)
copy(cache_path, temp_filename)
return temp_filename
# Returning temporary file object?
elif temp_file_obj:
temp_file, temp_filename = tempfile.mkstemp(dir=self.tmp_dir)
os.close(temp_file)
copy(cache_path, temp_filename)
temp_file = open(temp_filename, "rb")
return temp_file
