def __init__(self, blob_host_uri):
"""Initialize GridFS blob host.
Args:
blob_host_uri: MongoDB uri (mongodb://username:password@host:port/database)
"""
BLOBHost.__init__(self, blob_host_uri)
try:
# connect to mongo instance
self.client = MongoClient(
self.blob_host_uri,
serverSelectionTimeoutMS=CONNECTION_TIMEOUT)
# check connection
self.client.server_info()
# get database name from uri
database_name = blob_host_uri.split("/")[-1]
# connect to database
self.database = self.client[database_name]
# connect to gridfs
self.fs = gridfs.GridFS(self.database)
except Exception as e:
raise BLOBError(
"Unable to create the connection to the GridFS collection: %s"
% str(e))
def setUpClass(cls):
blob_host_factory = BLOBHostFactory('GridFS', MONGODB_URI)
cls.blob_host = blob_host_factory.create_blob_host()
if len(list(cls.blob_host.fs.find())) != 0:
raise BLOBError(
'Unable to perform the tests if the database is not empty.')
def get(self, handle):
"""Returns a blob
Args:
handle: blob id
Returns:
"""
try:
if self.fs.exists(ObjectId(handle)):
with self.fs.get(ObjectId(handle)) as blob:
return blob.read()
else:
raise BLOBError('No file found for the given id.')
except:
raise BLOBError(
'An unexpected error occurred while retrieving the file.')
def _create_gridfs_host(self):
"""Returns a GridFS host
Returns:
"""
if self.blob_host_uri is not None:
return GridFSBLOBHost(self.blob_host_uri)
else:
raise BLOBError('BLOB_HOST_URI should be set.')
def _create_dspace_host(self):
"""Returns a DSpace host
Returns:
"""
if self.blob_host_uri is not None and self.blob_host_user is not None and self.blob_host_password is not None:
return DSpaceBLOBHost(self.blob_host_uri, self.blob_host_user, self.blob_host_password)
else:
raise BLOBError('BLOB_HOST_URI, BLOB_HOST_USER and BLOB_HOST_PASSWORD should be set.')
def create_blob_host(self):
"""Returns a blob host
Returns:
"""
if self.blob_host is not None and self.blob_host in self.BLOB_HOSTS:
if self.blob_host == self.BLOB_HOSTS[0]:
return self._create_dspace_host()
elif self.blob_host == self.BLOB_HOSTS[1]:
return self._create_gridfs_host()
else:
raise BLOBError('BLOB_HOST should take a value in ' + str(self.BLOB_HOSTS))
def get(self, handle):
"""Return a blob with the given handle.
Args:
handle(str): ObjectId of the Blob object to retrieve.
Returns:
bytes: the content of the file stored with the given Blob id.
Raises:
BlobError: if the object does not exists or an unexpected error occurs.
"""
try:
if not self.fs.exists(ObjectId(handle)):
raise BLOBError("No file found with the given ID.")
with self.fs.get(ObjectId(handle)) as blob:
return blob.read()
except Exception as exc:
raise BLOBError(
f"An unexpected error occurred while retrieving the file: {str(exc)}"
)
def delete(self, handle):
"""Deletes a blob
Args:
handle: blob id
Returns:
"""
try:
if self.fs.exists(ObjectId(handle)):
self.fs.delete(ObjectId(handle))
except:
raise BLOBError("An error occurred while deleting the file.")
def delete(self, handle):
"""Delete a blob
Args:
handle: blob id
Returns:
"""
try:
if self.fs.exists(ObjectId(handle)):
self.fs.delete(ObjectId(handle))
except Exception as exc:
raise BLOBError(
f"An error occurred while deleting the file: {str(exc)}")
def save(self, blob, filename=None, metadata=None):
"""Saves a blob
Args:
blob:
filename:
metadata:
Returns:
"""
try:
if metadata is None:
metadata = dict()
blob_id = self.fs.put(blob, filename=filename, metadata=metadata)
except Exception, e:
raise BLOBError("An error occurred while saving the file.")
def save(self, blob, filename=None, metadata=None):
"""Save a blob.
Args:
blob:
filename:
metadata:
Returns:
"""
try:
if metadata is None:
metadata = dict()
blob_id = self.fs.put(blob, filename=filename, metadata=metadata)
except Exception as exc:
raise BLOBError(
f"An error occurred while saving the file: {str(exc)}")
return blob_id
