Updated on 2024-07-24 GMT+08:00

Managing Object Metadata

Scenarios

Object metadata is a set of name-value pairs that describe the object, and are used for object management.

Currently, only the metadata defined by the system is supported.

The metadata defined by the system is classified into the following types: system-controlled and user-controlled. For example, metadata such as Last-Modified is controlled by the system and cannot be modified. You can modify the metadata such as ContentLanguage through the API. The metadata that can be modified is described as follows:

Table 1 OBS metadata

Name

Description

ContentDisposition

Provides a default file name for the object that is being requested. When an object is being downloaded or accessed, the file with the default file name is directly displayed in the browser or a download dialog box is displayed if the file is being accessed.

For example, select ContentDisposition as the metadata name and enter attachment;filename="testfile.xls" as the metadata value for an object. If you access the object through a link, a dialog box is directly displayed for downloading objects, and the object name is changed to testfile.xls.

For details, see the definition about ContentDisposition in HTTP.

ContentLanguage

Indicates the language or languages intended for the audience. Therefore, a user can differentiate according to the user's preferred language. For details, see the definition about ContentLanguage in HTTP.

WebsiteRedirectLocation

Redirects an object to another object or an external URL. The redirection function is implemented using static website hosting.

For example, you can perform the following operations to implement object redirection:

  1. Set metadata of object testobject.html in the root directory of bucket testbucket. Select WebsiteRedirectLocation for Name and enter http://www.example.com for Value.
    NOTE:

    OBS only supports redirection for objects in the root directory of a bucket.

  2. Configure static website hosting for bucket testbucket, and set the object testobject.html in the bucket as the default home page of the hosted static website.
  3. If you access object testobject.html through the URL link provided on the Configure Static Website Hosting page, the access request is redirected to http://www.example.com.

ContentEncoding

Content encoding format when an object is downloaded. The options are as follows:

  • Standard: compress, deflate, exi, identity, gzip, and pack200-gzip
  • Others: br, bzip2, lzma, peerdist, sdch, xpress, and xz

CacheControl

Cache behavior of the web page when the specified object is downloaded.

  • Cacheability: public, private, no-cache, and only-if-cached
  • Expiration time: max-age=<seconds>, s-maxage=<seconds>, max-stale[=<seconds>], min-fresh=<seconds>, stale-while-revalidate=<seconds>, stale-if-error=<seconds>
  • Re-verification and reloading: must-revalidate, proxy-revalidate, and immutable
  • Others: no-store and no-transform

Expires

Cache expiration time (GMT)

ContentType

File type of an object.

For details, see Object Metadata Content-Type.

  • When versioning is enabled for a bucket, you can set metadata for objects which are Latest Version, but cannot set metadata for objects which are Historical Version.
  • You cannot configure object metadata for an Archive or Deep Archive object.

Object Metadata Content-Type

When an object is uploaded to OBS through OBS Console or a tool, the system automatically matches the value of Content-Type based on the file name extension of the object. When you access an object through a web browser, the system specifies an application to open the object according to the value of Content-Type. You can modify the Content-Type of an object based on its file name extension.

If you upload an object by calling an API, specify the value of Content-Type because the system does not automatically match the value of Content-Type.

Table 2 Common Content-Type values

File Name Extension

Content-Type

File Name Extension

Content-Type

.* (binary stream, unknown file type)

application/octet-stream

.7z

application/x-7z-compressed

.001

application/x-001

.301

application/x-301

.323

text/h323

.906

application/x-906

.907

drawing/907

.a11

application/x-a11

.acp

audio/x-mei-aac

.ai

application/postscript

.aif

audio/aiff

.aifc

audio/aiff

.aiff

audio/aiff

.anv

application/x-anv

.asa

text/asa

.asf

video/x-ms-asf

.asp

text/asp

.asx

video/x-ms-asf

.au

audio/basic

.avi

video/avi

.awf

application/vnd.adobe.workflow

.biz

text/xml

.bmp

application/x-bmp

.bot

application/x-bot

.c4t

application/x-c4t

.c90

application/x-c90

.cal

application/x-cals

.cat

application/vnd.ms-pki.seccat

.cdf

application/x-netcdf

.cdr

application/x-cdr

.cel

application/x-cel

.cer

application/x-x509-ca-cert

.cg4

application/x-g4

.cgm

application/x-cgm

.cit

application/x-cit

.class

java/*

.cml

text/xml

.cmp

application/x-cmp

.cmx

application/x-cmx

.cot

application/x-cot

.crl

application/pkix-crl

.crt

application/x-x509-ca-cert

.csi

application/x-csi

.css

text/css

.cut

application/x-cut

.dbf

application/x-dbf

.dbm

application/x-dbm

.dbx

application/x-dbx

.dcd

text/xml

.dcx

application/x-dcx

.der

application/x-x509-ca-cert

.dgn

application/x-dgn

.dib

application/x-dib

.dll

application/x-msdownload

.doc

application/msword

.docx

application/vnd.openxmlformats-officedocument.wordprocessingml.document

.drw

application/x-drw

.dot

application/msword

.dwf

Model/vnd.dwf

.dtd

text/xml

.dwg

application/x-dwg

.dwf

application/x-dwf

.dxf

application/x-dxf

.dxb

application/x-dxb

.emf

application/x-emf

.edn

application/vnd.adobe.edn

.ent

text/xml

.eml

message/rfc822

.eps

application/x-ps

.epi

application/x-epi

.etd

application/x-ebx

.eps

application/postscript

.fax

image/fax

.exe

application/x-msdownload

.fif

application/fractals

.fdf

application/vnd.fdf

.frm

application/x-frm

.fo

text/xml

.gbr

application/x-gbr

.g4

application/x-g4

.gif

image/gif

.

application/x-

.gp4

application/x-gp4

.gl2

application/x-gl2

.hmr

application/x-hmr

.hgl

application/x-hgl

.hpl

application/x-hpl

.hpg

application/x-hpgl

.hrf

application/x-hrf

.hqx

application/mac-binhex40

.htc

text/x-component

.hta

application/hta

.html

text/html

.htm

text/html

.htx

text/html

.htt

text/webviewhtml

.ico

image/x-icon

.icb

application/x-icb

.iff

application/x-iff

.ico

application/x-ico

.igs

application/x-igs

.ig4

application/x-g4

.img

application/x-img

.iii

application/x-iphone

.isp

application/x-internet-signup

.ins

application/x-internet-signup

.java

java/*

.IVF

video/x-ivf

.jpe

image/jpeg

.jfif

image/jpeg

.jpeg

image/jpeg

.jpe

application/x-jpe

.jpg

application/x-jpg

.jpg

image/jpeg

.jsp

text/html

.js

text/javascript

.lar

application/x-laplayer-reg

.la1

audio/x-liquid-file

.lavs

audio/x-liquid-secure

.latex

application/x-latex

.lmsff

audio/x-la-lms

.lbm

application/x-lbm

.ltr

application/x-ltr

.ls

application/x-javascript

.m2v

video/x-mpeg

.m1v

video/x-mpeg

.m4e

video/mpeg4

.m3u

audio/mpegurl

.man

application/x-troff-man

.mac

application/x-mac

.mdb

application/msaccess

.math

text/xml

.mfp

application/x-shockwave-flash

.mdb

application/x-mdb

.mhtml

message/rfc822

.mht

message/rfc822

.mid

audio/mid

.mi

application/x-mi

.mil

application/x-mil

.midi

audio/mid

.mnd

audio/x-musicnet-download

.mml

text/xml

.mocha

application/x-javascript

.mns

audio/x-musicnet-stream

.mp1

audio/mp1

.movie

video/x-sgi-movie

.mp2v

video/mpeg

.mp2

audio/mp2

.mp4

video/mp4

.mp3

audio/mp3

.mpd

application/vnd.ms-project

.mpa

video/x-mpg

.mpeg

video/mpg

.mpe

video/x-mpeg

.mpga

audio/rn-mpeg

.mpg

video/mpg

.mps

video/x-mpeg

.mpp

application/vnd.ms-project

.mpv

video/mpg

.mpt

application/vnd.ms-project

.mpw

application/vnd.ms-project

.mpv2

video/mpeg

.mtx

text/xml

.mpx

application/vnd.ms-project

.net

image/pnetvue

.mxp

application/x-mmxp

.nws

message/rfc822

.nrf

application/x-nrf

.out

application/x-out

.odc

text/x-ms-odc

.p12

application/x-pkcs12

.p10

application/pkcs10

.p7c

application/pkcs7-mime

.p7b

application/x-pkcs7-certificates

.p7r

application/x-pkcs7-certreqresp

.p7m

application/pkcs7-mime

.pc5

application/x-pc5

.p7s

application/pkcs7-signature

.pcl

application/x-pcl

.pci

application/x-pci

.pdf

application/pdf

.pcx

application/x-pcx

.pdx

application/vnd.adobe.pdx

.pfx

application/x-pkcs12

.pgl

application/x-pgl

.pic

application/x-pic

.pko

application/vnd.ms-pki.pko

.pl

application/x-perl

.plg

text/html

.pls

audio/scpls

.plt

application/x-plt

.png

image/png

.png

application/x-png

.pot

application/vnd.ms-powerpoint

.ppa

application/vnd.ms-powerpoint

.ppm

application/x-ppm

.pps

application/vnd.ms-powerpoint

.ppt

application/vnd.ms-powerpoint

.ppt

application/x-ppt

.pr

application/x-pr

.prf

application/pics-rules

.prn

application/x-prn

.prt

application/x-prt

.ps

application/x-ps

.ps

application/postscript

.ptn

application/x-ptn

.pwz

application/vnd.ms-powerpoint

.r3t

text/vnd.rn-realtext3d

.ra

audio/vnd.rn-realaudio

.ram

audio/x-pn-realaudio

.ras

application/x-ras

.rat

application/rat-file

.rdf

text/xml

.rec

application/vnd.rn-recording

.red

application/x-red

.rgb

application/x-rgb

.rjs

application/vnd.rn-realsystem-rjs

.rjt

application/vnd.rn-realsystem-rjt

.rlc

application/x-rlc

.rle

application/x-rle

.rm

application/vnd.rn-realmedia

.rmf

application/vnd.adobe.rmf

.rmi

audio/mid

.rmj

application/vnd.rn-realsystem-rmj

.rmm

audio/x-pn-realaudio

.rmp

application/vnd.rn-rn_music_package

.rms

application/vnd.rn-realmedia-secure

.rmvb

application/vnd.rn-realmedia-vbr

.rmx

application/vnd.rn-realsystem-rmx

.rnx

application/vnd.rn-realplayer

.rp

image/vnd.rn-realpix

.rpm

audio/x-pn-realaudio-plugin

.rsml

application/vnd.rn-rsml

.rt

text/vnd.rn-realtext

.rtf

application/msword

.rtf

application/x-rtf

.rv

video/vnd.rn-realvideo

.sam

application/x-sam

.sat

application/x-sat

.sdp

application/sdp

.sdw

application/x-sdw

.sit

application/x-stuffit

.slb

application/x-slb

.sld

application/x-sld

.slk

drawing/x-slk

.smi

application/smil

.smil

application/smil

.smk

application/x-smk

.snd

audio/basic

.sol

text/plain

.sor

text/plain

.spc

application/x-pkcs7-certificates

.spl

application/futuresplash

.spp

text/xml

.ssm

application/streamingmedia

.sst

application/vnd.ms-pki.certstore

.stl

application/vnd.ms-pki.stl

.stm

text/html

.sty

application/x-sty

.svg

text/svg+xml

.swf

application/x-shockwave-flash

.tdf

application/x-tdf

.tg4

application/x-tg4

.tga

application/x-tga

.tif

image/tiff

.tif

application/x-tif

.tiff

image/tiff

.tld

text/xml

.top

drawing/x-top

.torrent

application/x-bittorrent

.tsd

text/xml

.txt

text/plain

.uin

application/x-icq

.uls

text/iuls

.vcf

text/x-vcard

.vda

application/x-vda

.vdx

application/vnd.visio

.vml

text/xml

.vpg

application/x-vpeg005

.vsd

application/vnd.visio

.vsd

application/x-vsd

.vss

application/vnd.visio

.vst

application/vnd.visio

.vst

application/x-vst

.vsw

application/vnd.visio

.vsx

application/vnd.visio

.vtx

application/vnd.visio

.vxml

text/xml

.wav

audio/wav

.wax

audio/x-ms-wax

.wb1

application/x-wb1

.wb2

application/x-wb2

.wb3

application/x-wb3

.wbmp

image/vnd.wap.wbmp

.wiz

application/msword

.wk3

application/x-wk3

.wk4

application/x-wk4

.wkq

application/x-wkq

.wks

application/x-wks

.wm

video/x-ms-wm

.wma

audio/x-ms-wma

.wmd

application/x-ms-wmd

.wmf

application/x-wmf

.wml

text/vnd.wap.wml

.wmv

video/x-ms-wmv

.wmx

video/x-ms-wmx

.wmz

application/x-ms-wmz

.wp6

application/x-wp6

.wpd

application/x-wpd

.wpg

application/x-wpg

.wpl

application/vnd.ms-wpl

.wq1

application/x-wq1

.wr1

application/x-wr1

.wri

application/x-wri

.wrk

application/x-wrk

.ws

application/x-ws

.ws2

application/x-ws

.wsc

text/scriptlet

.wsdl

text/xml

.wvx

video/x-ms-wvx

.xdp

application/vnd.adobe.xdp

.xdr

text/xml

.xfd

application/vnd.adobe.xfd

.xfdf

application/vnd.adobe.xfdf

.xhtml

text/html

.xls

application/vnd.ms-excel

.xls

application/x-xls

.xlw

application/x-xlw

.xml

text/xml

.xpl

audio/scpls

.xq

text/xml

.xql

text/xml

.xquery

text/xml

.xsd

text/xml

.xsl

text/xml

.xslt

text/xml

.xwd

application/x-xwd

.x_b

application/x-x_b

.sis

application/vnd.symbian.install

.sisx

application/vnd.symbian.install

.x_t

application/x-x_t

.ipa

application/vnd.iphone

.apk

application/vnd.android.package-archive

.xap

application/x-silverlight-app

.zip

application/zip

.rar

application/x-rar-compressed

User-Defined Object Metadata

You can add the user-defined metadata whose name starts with x-obs-meta- for easy object management. When you retrieve or query the metadata of the object, the added user-defined metadata will be returned in the response header. The user-defined metadata is limited to 8 KB in size. To measure the total size of user-defined metadata, sum the number of bytes in the UTF-8 encoding of each key and value.

The user-defined metadata keys are case insensitive, but are stored in lowercase by OBS. The key values are case sensitive.

The following is an example.

1
2
3
4
5
6
7
PUT /key HTTP/1.1
Host: bucket01.obs.myhuaweicloud.com
x-obs-meta-Test1: Test Meta1

HEAD /Key HTTP/1.1
Host: bucket01.obs.myhuaweicloud.com
x-obs-meta-test1: Test Meta1

Both user-defined metadata keys and their values must conform to US-ASCII standards. If non-ASCII or unrecognizable characters are necessary, they must be encoded or decoded in URL or Base64 on the client side, because the server side does not perform any decoding.

How to Use

You can use OBS Console, APIs, SDKs, OBS Browser+, or obsutil to customize object metadata.

Tool

Reference

OBS Console

Configuring Object Metadata

SDKs

OBS supports software development kits (SDKs) in multiple languages. For details, see the corresponding developer guide on the SDK Overview page.

API

Modifying Object Metadata

OBS Browser+

-

obsutil

Uploading an Object