Spectra Logic

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Get Object

Description

Retrieves an object from storage. Spectra Logic recommends using Spectra S3 requests to create a GET job rather than using this request stand alone in a strict Amazon S3 manner. This is particularly important when getting many small objects or getting very large objects that have been broken up for physical placement. This is an Amazon S3 compatible operation with additional request parameters. The job and offset parameters should always be used when doing a GET object as part of a bulk GET job.

If the object is on tape, clients should expect latency and/or non-error response codes detailed below.

See Get Object for Amazon S3 operation details.

Notes:

§	A Create Bulk GET (see page 149) request should be issued to the BlackPearl system before the GET object request. The BlackPearl system may choose to fail any GET object request which does not match the plan returned by the prior Create Bulk GET request.

§	For more information about bulk GET jobs, see Processing a Bulk GET Job.

§	If the job and offset parameters are not provided and the object has multiple parts because it was PUT using multipart upload, or it was PUT using a Spectra S3 PUT job and the object was broken up into more than one part, the GET request fails.

Requests

Syntax

GET http[s]://{datapathDNSname}/{bucket_name}/{object_name}​[?job={string}][&offset={64‑bit integer}]

Request Parameters

Parameter	Description	Required
job	The UUID or a unique attribute for the job.	recommended
offset	The offset in bytes from the start of the object.	recommended

Request Header

§

The HTTP header for the checksum is returned when applicable (see Put Object), so that the client can verify that the data received is correct. End-to-end data protection requires that the client provide the CRC when uploading the object and then verify the CRC after downloading the object at a later time. The BlackPearl system also verifies the CRC when reading from physical data stores so the system can identify problems before transmitting data to the client.

§	This operation supports the HTTP Range header as implemented by Amazon S3 to download the specified range bytes of an object. See Get Object for more information.

Responses

Response Elements

The operation returns a header, the requested object content, and status information. It does not return response elements.

When possible, the response header has the status code 200 OK.

The header may also contain the following non-error statuses:

§	304 Not Modified (without object content):

§	if the `if-none-match` header was specified, but the object ETag is different than the given tag;

§	if the `if-modified-since` header was specified but the object has not been modified since the given time.

§

307 Temporary Redirect: In the event a tape library cannot retrieve an object within the allotted time, it will respond with 307 Temporary Redirect (along with the host address and port of the specific BlackPearl system which contains this object) before the timeout expires, and continue retrieving the object. The client must resend the `GET Object` request to the given address and port.

§	412 Precondition Failed (without object content):

§	`if-match` header was specified, but the object ETag did not match the specified tag;

§	`if-unmodified-since` header was specified but the object has been modified since the given time.

Example

Sample Request

This request GETs the object named “object1” from the bucket “bucket1”.

GET http://blackpearl-hostname/bucket1/object1 HTTP/1.1

Sample Response

HTTP/1.1 200 OK

{object data}