Jawei, Li f1cb839979 OBS api-ref 2.0.38.SP5

Reviewed-by: gtema <artem.goncharov@gmail.com>
Co-authored-by: Jawei, Li <lijiawei5@huawei.com>
Co-committed-by: Jawei, Li <lijiawei5@huawei.com>

2022-11-03 11:54:51 +00:00

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Downloading Objects

Functions

This operation downloads objects from OBS. Before using this GET operation, check that you have the read permission for the target object. If the object owner has granted anonymous users the read permission for the object, anonymous users can access this object without using the authentication header field.

Server-Side Encryption

If the object uploaded to the server is encrypted on the server using the encryption key provided by the client, downloading the object requires including the encryption key in the message.

Versioning

By default, the GET operation returns the current version of an object. If the current version of the object is a deletion marker, OBS returns a code meaning non-existence of the object. To obtain an object of a specified version, the versionId parameter can be used to specify the desired version.

OBS Cold Objects

If the object to be downloaded is a Cold object, restore it before downloading it. The response varies with the retrieval status of the object. If the object has been restored, the x-obs-restore header is returned indicating the expiry date of the object when it is successfully downloaded. If you request downloading Cold objects that are not restored or are being restored, a 403 Forbidden error is returned.

Request Syntax

GET /ObjectName HTTP/1.1 
Host: bucketname.obs.region.example.com
Date: date
Authorization: authorization
Range:bytes=byte_range 
<Optional Additional Header>

The field is optional. If it does not exist, you can obtain the whole content.

Request Parameters

In a GET request, you can override values for a set of message headers using the request parameters. Message headers that you can override are Content-Type, Content-Language, Expires, Cache-Control, Content-Disposition, and Content-Encoding. If the target object has multiple versions, use the versionId parameter to specify the version to be downloaded. For details, see Table 1.

OBS does not process Accept-Encoding carried in a request or compress or decompress the uploaded data. The client determines whether to compress or decompress the data. Some HTTP clients may decompress data based on the Content-Encoding returned by the server. The client program needs to determine whether to decompress and how to decompress the data. To decompress the data, it can modify Content-Encoding (the object metadata stored in OBS) or rewrite Content-Encoding the object is downloaded. If an object download request specifies the rewrite header, the standard HTTP message header returned by OBS is subject to the rewrite content specified in the request.

**Table 1** Request parameters
Parameter	Description	Mandatory
response-content-type	Rewrites the Content-Type header in the response. Type: string	No
response-content-language	Rewrites the Content-Language header in the response. Type: string	No
response-expires	Rewrites the Expires header in the response. Type: string	No
response-cache-control	Rewrites the Cache-Control header in the response. Type: string	No
response-content-disposition	Rewrites the Content-Disposition header in the response. Type: string Example: response-content-disposition=attachment; filename=utf-8''name1 In this example, the downloaded object is renamed name1*. If the new name contains Chinese characters, it must be URL-encoded.	No
response-content-encoding	Rewrites the Content-Encoding header in the response. Type: string	No
versionId	Indicates the version ID of the object whose content is obtained. Type: string	No
attname	Rewrites the Content-Disposition header in the response. Type: string Example: attname=name1 Rename the downloaded object as name1.	No

Request Headers

This request uses common headers. In addition, you can add additional headers to this request. Table 2 describes the additional headers.

**Table 2** Request headers
Header	Description	Mandatory
Range	Obtains the object content within the scope defined by Range. If the parameter value is invalid, the entire object is obtained. Range value starts from 0, and the maximum value equals the object length minus 1. The start value of Range is mandatory. If only the start value is specified, the system obtains the object content from the start value to default maximum value. After the Range header field is carried, the value of ETag in the response message is the ETag of the object instead of the ETag of the object in the Range field. Type: string bytes=byte_range Example 1: bytes=0-4 Example 2: bytes=1024 Example 3: bytes=10-20, 30-40 (multiple ranges)	No
If-Modified-Since	Returns the object only if it has been modified since the time specified by this header. Otherwise, 304 Not Modified is returned. Type: HTTP time character string complying with the format specified at http://www.ietf.org/rfc/rfc2616.txt	No
If-Unmodified-Since	Returns the object only if it has not been modified since the time specified by this header. Otherwise, 412 Precondition Failed is returned. Type: HTTP time character string complying with the format specified at http://www.ietf.org/rfc/rfc2616.txt	No
If-Match	Returns the object only if its ETag is the same as the one specified by this header. Otherwise, 412 Precondition Failed is returned. Type: string (Example: 0f64741bf7cb1089e988e4585d0d3434)	No
If-None-Match	Returns the object only if its ETag is different from the one specified by this header. Otherwise, 304 Not Modified is returned. Type: string (Example: 0f64741bf7cb1089e988e4585d0d3434)	No
x-obs-server-side-encryption-customer-algorithm	Indicates an encryption algorithm. The header is used in SSE-C mode. Type: string Example: x-obs-server-side-encryption-customer-algorithm:AES256 Constraint: This header must be used together with x-obs-server-side-encryption-customer-key and x-obs-server-side-encryption-customer-key-MD5.	No. This header is required when SSE-C is used.
x-obs-server-side-encryption-customer-key	Indicates a key used to encrypt objects. The header is used in SSE-C mode. This key is used to decrypt objects. Type: string Example: x-obs-server-side-encryption-customer-key:K7QkYpBkM5+hca27fsNkUnNVaobncnLht/rCB2o/9Cw= Constraint: This header is a Base64-encoded 256-bit key and must be used together with x-obs-server-side-encryption-customer-algorithm and x-obs-server-side-encryption-customer-key-MD5.	No. This header is required when SSE-C is used.
x-obs-server-side-encryption-customer-key-MD5	Indicates the MD5 value of a key used to encrypt objects. The header is used in SSE-C mode. The MD5 value is used to check whether any error occurs during the transmission of the key. Type: string Example: x-obs-server-side-encryption-customer-key-MD5:4XvB3tbNTN+tIEVa0/fGaQ== Constraint: This header is a Base64-encoded 128-bit MD5 value and must be used together with x-obs-server-side-encryption-customer-algorithm and x-obs-server-side-encryption-customer-key.	No. This header is required when SSE-C is used.

Request Elements

This request involves no elements.

Response Syntax

HTTP/1.1 status_code 
Content-Type: type 
Date: date 
Content-Length: length 
Etag: etag 
Last-Modified: time 

<Object Content>

Response Headers

The response to the request uses common headers. For details, see Table 1.

In addition to the common response headers, the following message headers may also be used. For details, see Table 3.

**Table 3** Additional response header parameters
Header	Description
x-obs-expiration	When an object has its lifecycle rule, the object expiration time is subject to its lifecycle rule. This header field is use expiry-date to describe the object expiration date. If the lifecycle rule is configured only for the entire bucket not individual objects, the object expiration time is subject to the bucket lifecycle rule. This header field uses the expiry-date and rule-id to describe the detailed expiration information of objects. If no lifecycle rule is configured, this header field is not contained in the response. Type: string
x-obs-website-redirect-location	Indicates the redirected-to location. If the bucket is configured with website information, this parameter can be set for the object metadata so that the website endpoint will evaluate the request for the object as a 301 redirect to another object in the same bucket or an external URL. Type: string
x-obs-delete-marker	Indicates whether an object is a deletion marker. If the object is not marked as deleted, the response does not contain this header. Type: boolean Valid values: true or false The default value is false.
x-obs-version-id	Object version ID. If the object has no version number specified, the response does not contain this header. Valid value: character string Default value: none
x-obs-server-side-encryption	This header is included in a response if SSE-KMS is used. Type: string Example: x-obs-server-side-encryption:kms
x-obs-server-side-encryption-kms-key-id	Indicates the master key ID. This header is included in a response if SSE-KMS is used. Type: string Format: regionID:domainID:key/key_id regionID is the ID of the region to which the key belongs. domainID is the account ID of the tenant to which the key belongs. key_id is the key ID used in this encryption. Example: *x-obs-server-side-encryption-kms-key-id:region:domainiddomainiddomainiddoma0001:key/4f1cd4de-ab64-4807-920a-47fc42e7f0d0*
x-obs-server-side-encryption-customer-algorithm	Indicates a decryption algorithm. This header is included in a response if SSE-C is used. Type: string Example: x-obs-server-side-encryption-customer-algorithm:AES256
x-obs-server-side-encryption-customer-key-MD5	Indicates the MD5 value of a key used to decrypt objects. This header is included in a response if SSE-C is used. Type: string Example: x-obs-server-side-encryption-customer-key-MD5:4XvB3tbNTN+tIEVa0/fGaQ==
x-obs-object-type	If the object is not a normal one, this header field is returned. The value can be Appendable. Type: string
x-obs-next-append-position	This header field is returned when the object is an appendable object. Type: integer

Response Elements

This response involves no elements.

Error Responses

No special error responses are returned. For details about error responses, see Table 2.

Sample Request 1

Download the entire object.

GET /object01 HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: WED, 01 Jul 2015 04:24:33 GMT
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:NxtSMS0jaVxlLnxlO9awaMTn47s=

Sample Response 1

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: 8DF400000163D3F2A89604C49ABEE55E
Accept-Ranges: bytes
ETag: "3b46eaf02d3b6b1206078bb86a7b7013"
Last-Modified: WED, 01 Jul 2015 01:20:29 GMT
Content-Type: binary/octet-stream
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCSQwxJ2I1VvxD/Xgwuw2G2RQax30gdXU
Date: WED, 01 Jul 2015 04:24:33 GMT
Content-Length: 4572

[4572 Bytes object content]

Sample Request 2

Download the specified range of an object (download a range of an object).

GET /object01 HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: Mon, 14 Sep 2020 09:59:04 GMT
Range:bytes=20-30
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:mNPLWQMDWg30PTkAWiqJaLl3ALg=

Download the specified range of an object (download multiple ranges of an object).

GET /object01 HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: Mon, 14 Sep 2020 10:02:43 GMT
Range:bytes=20-30,40-50
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:ZwM7Vk2d7sD9o8zRsRKehgKQDkk=

Sample Response 2

Download the specified range of an object (download a range of an object).

HTTP/1.1 206 Partial Content
Server: OBS
x-obs-request-id: 000001748C0DBC35802E360C9E869F31
Accept-Ranges: bytes
ETag: "2200446c2082f27ed2a569601ca4e360"
Last-Modified: Mon, 14 Sep 2020 01:16:20 GMT
Content-Range: bytes 20-30/4583
Content-Type: binary/octet-stream
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCSn2JHu4okx9NBRNZAvBGawa3lt3g31g
Date: Mon, 14 Sep 2020 09:59:04 GMT
Content-Length: 11

[ 11 Bytes object content]

Download the specified range of an object (download multiple ranges of an object).

HTTP/1.1 206 Partial Content
Server: OBS
x-obs-request-id: 8DF400000163D3F2A89604C49ABEE55E
Accept-Ranges: bytes
ETag: "2200446c2082f27ed2a569601ca4e360"
Last-Modified: Mon, 14 Sep 2020 01:16:20 GMT
Content-Type: multipart/byteranges;boundary=35bcf444-e65f-4c76-9430-7e4a68dd3d26
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCSIBWFOVW8eeWujkqSnoIANC2mNR1cdF
Date: Mon, 14 Sep 2020 10:02:43 GMT
Content-Length: 288

--35bcf444-e65f-4c76-9430-7e4a68dd3d26
Content-type: binary/octet-stream
Content-range: bytes 20-30/4583
[ 11 Bytes object content]
--35bcf444-e65f-4c76-9430-7e4a68dd3d26
Content-type: binary/octet-stream
Content-range: bytes 40-50/4583
[ 11 Bytes object content]
--35bcf444-e65f-4c76-9430-7e4a68dd3d26

Sample Request 4

Download an object if its Etag value matches.

GET /object01 HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: WED, 01 Jul 2015 04:24:33 GMT
If-Match: 682e760adb130c60c120da3e333a8b09
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:NxtSMS0jaVxlLnxlO9awaMTn47s=

Sample Response 4-1 (Non-Matched Etag)

If the Etag value of the stored object is not 682e760adb130c60c120da3e333a8b09, the system displays a message indicating that the download fails.

HTTP/1.1 412 Precondition Failed
Server: OBS
x-obs-request-id: 8DF400000163D3F2A89604C49ABEE55E
Content-Type: application/xml
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCSQwxJ2I1VvxD/Xgwuw2G2RQax30gdXU
Date: WED, 01 Jul 2015 04:20:51 GMT

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<Error>
  <Code>PreconditionFailed</Code>
  <Message>At least one of the pre-conditions you specified did not hold</Message> 
  <RequestId>8DF400000163D3F2A89604C49ABEE55E</RequestId>      
  <HostId>ha0ZGaSKVm+uLOrCXXtx4Qn1aLzvoeblctVXRAqA7pty10mzUUW/yOzFue04lBqu</HostId>
  <Condition>If-Match</Condition>
</Error>

Sample Response 4-2 (Successful Download)

If the Etag value of the stored object is 682e760adb130c60c120da3e333a8b09, the download is successful.

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: 5DEB00000164A21E1FC826C58F6BA001
Accept-Ranges: bytes
ETag: "682e760adb130c60c120da3e333a8b09"
Last-Modified: Mon, 16 Jul 2015 08:03:34 GMT
Content-Type: application/octet-stream
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCSbkdml1sLSvKnoHaRcOwRI+6+ustDwk
Date: Mon, 16 Jul 2015 08:04:00 GMT
Content-Length: 8

[ 8 Bytes object content]

Sample Request 5

Carry the signature in the URL when downloading an object.

GET /object02?AccessKeyId=H4IPJX0TQTHTHEBQQCEC&Expires=1532688887&Signature=EQmDuOhaLUrzrzRNZxwS72CXeXM%3D HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: Fri, 27 Jul 2018 10:52:31 GMT

Sample Response 5

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: 804F00000164DB5E5B7FB908D3BA8E00
ETag: "682e760adb130c60c120da3e333a8b09"
Last-Modified: Mon, 16 Jul 2015 08:03:34 GMT
Content-Type: application/octet-stream
x-obs-id-2: 32AAAUJAIAABAAAQAAEAABAAAQAAEAABCTlpxILjhVK/heKOWIP8Wn2IWmQoerfw
Date: Fri, 27 Jul 2018 10:52:31 GMT
Content-Length: 8

[ 8 Bytes object content]

Sample Request 6

Use the response-content-disposition parameter to download and rename an object.

GET /object01?response-content-disposition=attachment; filename*=utf-8''name1 HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: WED, 01 Jul 2015 04:24:33 GMT
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:NxtSMS0jaVxlLnxlO9awaMTn47s=

Sample Response 6

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: 804F00000164DB5E5B7FB908D3BA8E00
ETag: "682e760adb130c60c120da3e333a8b09"
Last-Modified: Mon, 16 Jul 2015 08:03:34 GMT
Content-Type: application/octet-stream
x-obs-id-2: 32AAAUJAIAABAAAQAAEAABAAAQAAEAABCTlpxILjhVK/heKOWIP8Wn2IWmQoerfw
Date: Fri, 27 Jul 2018 10:52:31 GMT
Content-Length: 8
Content-Disposition: attachment; filename*=utf-8''name1

[ 8 Bytes object content]

Sample Request 7

Use the attname parameter to download and rename an object.

GET /object01?attname=name1 HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: WED, 01 Jul 2015 04:24:33 GMT
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:NxtSMS0jaVxlLnxlO9awaMTn47s=

Sample Response 7

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: 804F00000164DB5E5B7FB908D3BA8E00
ETag: "682e760adb130c60c120da3e333a8b09"
Last-Modified: Mon, 16 Jul 2015 08:03:34 GMT
Content-Type: application/octet-stream
x-obs-id-2: 32AAAUJAIAABAAAQAAEAABAAAQAAEAABCTlpxILjhVK/heKOWIP8Wn2IWmQoerfw
Date: Fri, 27 Jul 2018 10:52:31 GMT
Content-Length: 8
Content-Disposition: attachment; filename*=utf-8''name1

[ 8 Bytes object content]

Parent topic: Operations on Objects

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