Class Blob (1.20.0)

Blob(
    name,
    bucket,
    chunk_size=None,
    encryption_key=None,
    kms_key_name=None,
    generation=None,
)

A wrapper around Cloud Storage's concept of an Object.

Parameters
Name	Description
`name`	`str` The name of the blob. This corresponds to the unique path of the object in the bucket. If bytes, will be converted to a unicode object. Blob / object names can contain any sequence of valid unicode characters, of length 1-1024 bytes when UTF-8 encoded.
`bucket`	`Bucket` The bucket to which this blob belongs.
`chunk_size`	`int` The size of a chunk of data whenever iterating (in bytes). This must be a multiple of 256 KB per the API specification.
`encryption_key`	`bytes` Optional 32 byte encryption key for customer-supplied encryption. See https://cloud.google.com/storage/docs/encryption#customer-supplied.
`kms_key_name`	`str` Optional resource name of Cloud KMS key used to encrypt the blob's contents.

Properties

acl

Create our ACL on demand.

bucket

Bucket which contains the object.

Returns
Type	Description
`Bucket`	The object's bucket.

cache_control

Scalar property getter.

chunk_size

Get the blob's default chunk size.

Returns
Type	Description
`int or NoneType`	The current blob's chunk size, if it is set.

client

The client bound to this blob.

component_count

Number of underlying components that make up this object.

See https://cloud.google.com/storage/docs/json_api/v1/objects

Returns
Type	Description
`int or NoneType`	The component count (in case of a composed object) or `None` if the blob's resource has not been loaded from the server. This property will not be set on objects not created via `compose`.

content_disposition

Scalar property getter.

content_encoding

Scalar property getter.

content_language

Scalar property getter.

content_type

Scalar property getter.

crc32c

Scalar property getter.

etag

Retrieve the ETag for the object.

See RFC 2616 (etags) and API reference docs.

Returns
Type	Description
`str or NoneType`	The blob etag or `None` if the blob's resource has not been loaded from the server. .. _RFC 2616 (etags): https://tools.ietf.org/html/rfc2616#section-3.11

event_based_hold

Scalar property getter.

generation

Retrieve the generation for the object.

See https://cloud.google.com/storage/docs/json_api/v1/objects

Returns
Type	Description
`int or NoneType`	The generation of the blob or `None` if the blob's resource has not been loaded from the server.

Methods

compose

compose(sources, client=None)

Concatenate source blobs into this one.

If user_project is set on the bucket, bills the API request to that project.

Parameters
Name	Description
`sources`	`list of Blob` blobs whose contents will be composed into this blob.
`client`	`Client or NoneType` Optional. The client to use. If not passed, falls back to the `client` stored on the blob's bucket.

create_resumable_upload_session

create_resumable_upload_session(
    content_type=None, size=None, origin=None, client=None
)

Create a resumable upload session.

Resumable upload sessions allow you to start an upload session from one client and complete the session in another. This method is called by the initiator to set the metadata and limits. The initiator then passes the session URL to the client that will upload the binary data. The client performs a PUT request on the session URL to complete the upload. This process allows untrusted clients to upload to an access-controlled bucket. For more details, see the documentation on signed URLs_.

.. _documentation on signed URLs: https://cloud.google.com/storage/ docs/access-control/signed-urls#signing-resumable

The content type of the upload will be determined in order of precedence:

The value passed in to this method (if not :data:None)
The value stored on the current blob
The default value ('application/octet-stream')

See the

object versioning
   <https://cloud.google.com/storage/docs/object-versioning>

and lifecycle <https://cloud.google.com/storage/docs/lifecycle> API documents for details.

If encryption_key is set, the blob will be encrypted with a customer-supplied_ encryption key.

If user_project is set on the bucket, bills the API request to that project.

Parameters
Name	Description
`size`	`int` (Optional). The maximum number of bytes that can be uploaded using this session. If the size is not known when creating the session, this should be left blank.
`content_type`	`str` (Optional) Type of content being uploaded.
`origin`	`str` (Optional) If set, the upload can only be completed by a user-agent that uploads from the given origin. This can be useful when passing the session to a web client.
`client`	`Client` (Optional) The client to use. If not passed, falls back to the `client` stored on the blob's bucket.

Exceptions
Type	Description
`GoogleCloudError`	if the session creation response returns an error status.

Returns
Type	Description
`str`	The resumable upload session URL. The upload can be completed by making an HTTP PUT request with the file's contents.

delete

delete(client=None)

Deletes a blob from Cloud Storage.

If user_project is set on the bucket, bills the API request to that project.

Parameter
Name	Description
`client`	`Client or NoneType` Optional. The client to use. If not passed, falls back to the `client` stored on the blob's bucket.

Exceptions
Type	Description
`NotFound`	(propagated from delete_blob).

Returns
Type	Description
`Blob`	The blob that was just deleted.

download_as_string

download_as_string(client=None, start=None, end=None)

Download the contents of this blob as a string.

If user_project is set on the bucket, bills the API request to that project.

Parameters
Name	Description
`client`	`Client or NoneType` Optional. The client to use. If not passed, falls back to the `client` stored on the blob's bucket.
`start`	`int` Optional, the first byte in a range to be downloaded.
`end`	`int` Optional, The last byte in a range to be downloaded.

Exceptions
Type	Description
`NotFound`

Returns
Type	Description
`bytes`	The data stored in this blob.

download_to_file

download_to_file(file_obj, client=None, start=None, end=None)

Download the contents of this blob into a file-like object.

Note: If the server-set property, media_link, is not yet initialized, makes an additional API request to load it.

.. literalinclude:: snippets.py :start-after: [START download_to_file] :end-before: [END download_to_file] :dedent: 4

The encryption_key should be a str or bytes with a length of at least 32.

For more fine-grained control over the download process, check out google-resumable-media_. For example, this library allows downloading parts of a blob rather than the whole thing.

If user_project is set on the bucket, bills the API request to that project.

Parameters
Name	Description
`file_obj`	`file` A file handle to which to write the blob's data.
`client`	`Client or NoneType` Optional. The client to use. If not passed, falls back to the `client` stored on the blob's bucket.
`start`	`int` Optional, the first byte in a range to be downloaded.
`end`	`int` Optional, The last byte in a range to be downloaded.

Exceptions
Type	Description
`NotFound`

download_to_filename

download_to_filename(filename, client=None, start=None, end=None)

Download the contents of this blob into a named file.

If user_project is set on the bucket, bills the API request to that project.

Parameters
Name	Description
`filename`	`str` A filename to be passed to `open`.
`client`	`Client or NoneType` Optional. The client to use. If not passed, falls back to the `client` stored on the blob's bucket.
`start`	`int` Optional, the first byte in a range to be downloaded.
`end`	`int` Optional, The last byte in a range to be downloaded.

Exceptions
Type	Description
`NotFound`

exists

exists(client=None)

Determines whether or not this blob exists.

If user_project is set on the bucket, bills the API request to that project.

Parameter
Name	Description
`client`	`Client or NoneType` Optional. The client to use. If not passed, falls back to the `client` stored on the blob's bucket.

Returns
Type	Description
`bool`	True if the blob exists in Cloud Storage.

from_string

from_string(uri, client=None)

Get a constructor for blob object by URI.

Parameters
Name	Description
`uri`	`str` The blob uri pass to get blob object.
`client`	`Client or NoneType` Optional. The client to use.

Returns
Type	Description
`Blob`	The blob object created. .. rubric:: Example Get a constructor for blob object by URI.. >>> from google.cloud import storage >>> from google.cloud.storage.blob import Blob >>> client = storage.Client() >>> blob = Blob.from_string("gs://bucket/object")

generate_signed_url

generate_signed_url(
    expiration=None,
    api_access_endpoint="https://storage.googleapis.com",
    method="GET",
    content_md5=None,
    content_type=None,
    response_disposition=None,
    response_type=None,
    generation=None,
    headers=None,
    query_parameters=None,
    client=None,
    credentials=None,
    version=None,
)

Generates a signed URL for this blob.

Note: If you are on Google Compute Engine, you can't generate a signed URL using GCE service account. Follow Issue 50_ for updates on this. If you'd like to be able to generate a signed URL from GCE, you can use a standard service account from a JSON file rather than a GCE service account.

If you have a blob that you want to allow access to for a set amount of time, you can use this method to generate a URL that is only valid within a certain time period.

This is particularly useful if you don't want publicly accessible blobs, but don't want to require users to explicitly log in.

Parameters
Name	Description
`expiration`	`Union[Integer, datetime.datetime, datetime.timedelta]` Point in time when the signed URL should expire.
`api_access_endpoint`	`str` Optional URI base.
`method`	`str` The HTTP verb that will be used when requesting the URL.
`content_md5`	`str` (Optional) The MD5 hash of the object referenced by `resource`.
`content_type`	`str` (Optional) The content type of the object referenced by `resource`.
`response_disposition`	`str` (Optional) Content disposition of responses to requests for the signed URL. For example, to enable the signed URL to initiate a file of `blog.png`, use the value `'attachment; filename=blob.png'`.
`response_type`	`str` (Optional) Content type of responses to requests for the signed URL. Ignored if content_type is set on object/blob metadata.
`generation`	`str` (Optional) A value that indicates which generation of the resource to fetch.
`headers`	`dict` (Optional) Additional HTTP headers to be included as part of the signed URLs. See: https://cloud.google.com/storage/docs/xml-api/reference-headers Requests using the signed URL must pass the specified header (name and value) with each request for the URL.
`query_parameters`	`dict` (Optional) Additional query paramtersto be included as part of the signed URLs. See: https://cloud.google.com/storage/docs/xml-api/reference-headers#query
`client`	`Client or NoneType` (Optional) The client to use. If not passed, falls back to the `client` stored on the blob's bucket.
`credentials`	`oauth2client.client.OAuth2Credentials or NoneType` (Optional) The OAuth2 credentials to use to sign the URL. Defaults to the credentials stored on the client used.
`version`	`str` (Optional) The version of signed credential to create. Must be one of 'v2' 'v4'.

Exceptions
Type	Description
`ValueError	when version is invalid.
`TypeError	when expiration is not a valid type.
`AttributeError	if credentials is not an instance of `google.auth.credentials.Signing`.

Returns
Type	Description
`str`	A signed URL you can use to access the resource until expiration.

Class Blob (1.20.0)

Parameters

Properties

acl

bucket

cache_control

chunk_size

client

component_count

content_disposition

content_encoding

content_language

content_type

crc32c

etag

event_based_hold

generation

Methods

compose

create_resumable_upload_session

delete

download_as_string

download_to_file

download_to_filename

exists

from_string

generate_signed_url