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Blob container API¶
The connection object provides a convenience API for easy access to blob tables.
Get blob container handle¶
Create a connection:
>>> from crate.client import connect
>>> client = connect([crate_host])
Get a blob container:
>>> container = client.get_blob_container('myfiles')
Store blobs¶
The container allows to store a blob without explicitly providing the hash for the blob. This feature is possible if the blob is provided as a seekable stream like object.
Store a StringIO stream:
>>> from io import BytesIO
>>> f = BytesIO(b'StringIO data')
>>> stringio_bob = container.put(f)
>>> stringio_bob
'0cd4511d696823779692484029f234471cd21f28'
Store from a file:
>>> from tempfile import TemporaryFile
>>> f = TemporaryFile()
>>> _ = f.write(b'File data')
>>> _ = f.seek(0)
>>> file_blob = container.put(f)
>>> file_blob
'ea6e03a4a4ee8a2366fe5a88af2bde61797973ea'
>>> f.close()
If the blob data is not provided as a seekable stream the hash must be provided explicitly:
>>> import hashlib
>>> string_data = b'String data'
>>> string_blob = hashlib.sha1(string_data).hexdigest()
>>> container.put(string_data, string_blob)
True
Check for existence¶
>>> container.exists(string_blob)
True
>>> container.exists('unknown')
False
Retrieve blobs¶
Blobs can be retrieved using its hash:
>>> blob_stream = container.get(string_blob)
>>> blob_stream
<generator ...>
>>> data = next(blob_stream)
>>> data == string_data
True
Delete blobs¶
Blobs can be deleted using its hash:
>>> container.delete(string_blob)
True
>>> container.exists(string_blob)
False
Trying to delete a not existing blob:
>>> container.delete(string_blob)
False