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# Copyright (c) 2012 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import blob_reference_store as datastore
from blob_reference_store import BlobReferenceStore
from appengine_wrappers import blobstore
from appengine_wrappers import files
BLOBSTORE_GITHUB = 'BlobstoreGithub'
# TODO(kalman): Re-write this class.
# - It uses BlobReader which is a synchronous method. We should be creating
# multiple async fetches, one for each partition, then exposing a Future
# interface which stitches them together.
# - It's very hard to reuse.
class AppEngineBlobstore(object):
"""A wrapper around the blobstore API, which stores the blob keys in
datastore.
"""
def __init__(self):
self._datastore = BlobReferenceStore()
def Set(self, key, blob, namespace):
"""Add a blob to the blobstore. |version| is used as part of the key so
multiple blobs with the same name can be differentiated.
"""
key = namespace + '.' + key
filename = files.blobstore.create()
with files.open(filename, 'a') as f:
f.write(blob)
files.finalize(filename)
blob_key = files.blobstore.get_blob_key(filename)
self._datastore.Set(datastore.BLOB_REFERENCE_BLOBSTORE, key, blob_key)
def Get(self, key, namespace):
"""Get a blob with version |version|.
"""
key = namespace + '.' + key
blob_key = self._datastore.Get(datastore.BLOB_REFERENCE_BLOBSTORE, key)
if blob_key is None:
return None
blob_reader = blobstore.BlobReader(blob_key)
return blob_reader.read()
def Delete(self, key, namespace):
"""Delete the blob with version |version| if it is found.
"""
key = namespace + '.' + key
blob_key = self._datastore.Delete(datastore.BLOB_REFERENCE_BLOBSTORE, key)
if blob_key is None:
return
blob_key.delete()
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