Listing Objects in a Bucket

Functions

This operation lists objects in a bucket. To use this operation, you must have the permission to read the bucket.

If you specify only the bucket name in the request, OBS returns descriptions for some or all of the objects (a maximum of 1,000 objects) in the bucket. If you also specify one or more parameters among prefix, marker, max-keys, and delimiter in the request, OBS returns a list of objects based on the semantics specified in Table 1.

You can also add the versions parameter to the request to list multiple versions of an object in a bucket.

Request Syntax

GET / HTTP/1.1 
 
Host: bucketname.obs.region.example.com
Date: date
Authorization: authorization

Request Syntax (for multi-version objects)

GET /?versions HTTP/1.1  
Host: bucketname.obs.region.example.com
Date: date
Authorization: authorization

Request Parameters

This request uses parameters to list some objects in a bucket. Table 1 describes the parameters.

**Table 1** Request parameters
Parameter	Description	Mandatory
prefix	Lists objects that begin with the specified prefix. Type: string	No
marker	Specifies a marker when listing objects in a bucket. With a marker configured, objects after this marker will be returned in alphabetical order. This field is used only for listing objects. Type: string	No
max-keys	Specifies the maximum number (from 1 to 1000) of objects returned (in alphabetical order) in the response. If the value is beyond this range, only 1,000 objects are returned by default. Type: integer	No
delimiter	Separator used to group object names. If a prefix is specified, objects with the same string from the prefix to the first delimiter are grouped into one CommonPrefixes. If no prefix is specified, objects with the same string from the first character to the first delimiter are grouped into one CommonPrefixes. For example, there are three objects (abcd, abcde, and bbcde) in a bucket. If delimiter is set to d and prefix is set to a, objects abcd and abcde are grouped into a CommonPrefixes with abcd as the prefix. If only delimiter is set to d, objects abcd and abcde are grouped into a CommonPrefixes with abcd as the prefix, and bbcde is grouped separately into another CommonPrefixes with bbcd as the prefix. For a parallel file system, if this parameter is not specified, all the content in the directory is recursively listed by default, and subdirectories are also listed. In big data scenarios, parallel file systems usually have deep directory levels and each directory has a large number of files. In such case, you are advised to configure [delimiter=/] to list the content in the current directory, but not list subdirectories, thereby improving the listing efficiency. Type: string	No
key-marker	Position to start with when objects are listed. This field is used only for listing versioned objects. Type: string Valid value: value of NextKeyMarker in the response body of the last request	No
version-id-marker	This parameter applies only when versioning is enabled. Specifies the version ID to start with when objects in a bucket are listed. Objects are listed in alphabetical order (a maximum of 1,000 objects are displayed at a time). This parameter is used together with the key-marker in the request. If the value of version-id-marker is not a version ID specified by key-marker, version-id-marker is invalid. Type: string Valid value: object version ID, that is, the value of NextVersionIdMarker in the response body of the last request	No

Request Headers

This request uses common request headers. For details, see Table 3.

Request Elements

This request contains no elements.

Response Syntax

HTTP/1.1 status_code
Date: date
x-obs-bucket-location: region
Content-Type: application/xml 
Content-Length: length
<Response Body>

Response Headers

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

Response Elements

This response lists objects in XML format. Specific elements are described in Table 2.

**Table 2** Response elements
Element	Description
ListBucketResult	A list of objects in a bucket Type: XML
Contents	Object metadata Type: XML Ancestor: ListBucketResult
CommonPrefixes	Group information. If you specify a delimiter in the request, the response contains group information in CommonPrefixes. Type: XML Ancestor: ListBucketResult
Delimiter	The delimiter parameter specified in a request Type: string Ancestor: ListBucketResult
ETag	Base64-encoded 128-bit MD5 digest of an object. ETag is the unique identifier of the object content. It can be used to determine whether the object content is changed. For example, if the ETag value is A when an object is uploaded, but this value has changed to B when the object is downloaded, it indicates that the object content has been changed. The ETag value is a hash of the object. The ETag reflects changes to the object content, rather than the object metadata. An uploaded object or copied object has a unique ETag after being encrypted using MD5. (If the object is encrypted on the server side, the ETag value is not the MD5 digest of the object, but the unique identifier calculated through server-side encryption.) Type: string Ancestor: ListBucketResult.Contents
Type	Object type. This parameter is returned when the object type is not Normal. Type: string Ancestor: ListBucketResult.Contents
ID	Domain ID of the object owner Type: string Ancestor: ListBucketResult.Contents.Owner
IsTruncated	Determines whether the returned list of objects is truncated. The value true indicates that the list was truncated and false indicates that the list was not truncated. Type: boolean Ancestor: ListBucketResult
Key	Object name Type: string Ancestor: ListBucketResult.Contents
LastModified	Time (UTC) when an object was last modified Type: date Ancestor: ListBucketResult.Contents
Marker	Marker for the position from which objects in a bucket will be listed Type: string Ancestor: ListBucketResult
NextMarker	A marker for the last returned object in the list. NextMarker is returned when not all the objects are listed. You can set the Marker value to list the remaining objects in follow-up requests. Type: string Ancestor: ListBucketResult
MaxKeys	Maximum number of objects returned Type: string Ancestor: ListBucketResult
Name	Name of the requested bucket Type: string Ancestor: ListBucketResult
Owner	User information, including the domain ID and name of the object owner Type: XML Ancestor: ListBucketResult.Contents
DisplayName	Name of the object owner Type: string Ancestor: ListBucketResult.Contents.Owner
Prefix	Prefix of an object name. Only objects whose names have this prefix are listed. Type: string Ancestor: ListBucketResult
Size	Object size in bytes Type: string Ancestor: ListBucketResult.Contents
StorageClass	Storage class of an object Type: string Value options: STANDARD, WARM, COLD Ancestor: ListBucketResult.Contents

**Table 3** Elements in the response message for listing multi-version objects.
Element	Description
ListVersionsResult	Container for the list of objects (including objects with multiple version IDs) Type: container
Name	Bucket name Type: string Ancestor: ListVersionsResult
Prefix	Prefix of an object name. Only objects whose names have this prefix are listed. Type: string Ancestor: ListVersionsResult
KeyMarker	Marker for the object key from which objects will be listed Type: string Ancestor: ListVersionsResult
VersionIdMarker	Object version ID to start with when objects are listed Type: string Ancestor: ListVersionsResult
NextKeyMarker	Key marker for the last returned object in the list. NextKeyMarker is returned when not all the objects are listed. You can set the KeyMarker value to list the remaining objects in follow-up requests. Type: string Ancestor: ListVersionsResult
NextVersionIdMarker	Version ID marker for the last returned object in the list. NextVersionIdMarker is returned when not all the objects are listed. You can set the VersionIdMarker value to list the remaining objects in follow-up requests. Type: string Ancestor: ListVersionsResult
MaxKeys	Maximum number of objects returned Type: string Ancestor: ListVersionsResult
IsTruncated	Indicates whether the returned list of objects is truncated. The value true indicates that the list was truncated and false indicates that the list was not truncated. Type: boolean Ancestor: ListVersionsResult
Version	Container of version information Type: container Ancestor: ListVersionsResult
DeleteMarker	Container for objects with deletion markers Type: container Ancestor: ListVersionsResult
Key	Object name Type: string Ancestor: ListVersionsResult.Version \| ListVersionsResult.DeleteMarker
VersionId	Object version ID Type: string Ancestor: ListVersionsResult, Version \| ListVersionsResult, DeleteMarker
IsLatest	Whether the object is the latest version. If the parameter value is true, the object is the latest version. Type: boolean Ancestor: ListVersionsResult.Version \| ListVersionsResult.DeleteMarker
LastModified	Time (UTC) when an object was last modified Type: date Ancestor: ListVersionsResult.Version \| ListVersionsResult.DeleteMarker
ETag	Base64-encoded 128-bit MD5 digest of an object. ETag is the unique identifier of the object content. It can be used to determine whether the object content is changed. The actual ETag is the hash value of the object. For example, if the ETag value is A when an object is uploaded, but this value has changed to B when the object is downloaded, it indicates that the object content has been changed. The ETag reflects changes to the object content, rather than the object metadata. An uploaded object or copied object has a unique ETag after being encrypted using MD5. Type: string Ancestor: ListVersionsResult.Version
Type	Object type. This parameter is returned when the object type is not Normal. Type: string Ancestor: ListVersionsResult.Version
Size	Object size in bytes Type: string Ancestor: ListVersionsResult.Version
Owner	User information, including the domain ID and name of the object owner Type: container Ancestor: ListVersionsResult.Version \| ListVersionsResult.DeleteMarker
ID	Domain ID of the object owner Type: string Ancestor: ListVersionsResult.Version.Owner \| ListVersionsResult.DeleteMarker.Owner
DisplayName	Name of the object owner Type: string Ancestor: ListVersionsResult.Version.Owner \| ListVersionsResult.DeleteMarker.Owner
StorageClass	Storage class of an object Type: string Value options: STANDARD, WARM, COLD Ancestor: ListVersionsResult.Version
CommonPrefixes	Group information. If you specify a delimiter in the request, the response contains group information in CommonPrefixes. Type: container Ancestor: ListVersionsResult
Prefix	Indicates a different prefix in the group information in CommonPrefixes. Type: string Ancestor: ListVersionsResult.CommonPrefixes

Error Responses

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

Sample Request: Listing All Objects

GET / HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: WED, 01 Jul 2015 02:28:25 GMT
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:KiyoYze4pmRNPYfmlXBfRTVxt8c=

Sample Response: Listing All Objects

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: BF260000016435D34E379ABD93320CB9
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCSXiN7GPL/yXM6OSBaYCUV1zcY5OelWp
Content-Type: application/xml
Date: WED, 01 Jul 2015 02:23:30 GMT
Content-Length: 586

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ListBucketResult xmlns="http://obs.example.com/doc/2015-06-30/">
  <Name>examplebucket</Name>
  <Prefix/>
  <Marker/>
  <MaxKeys>1000</MaxKeys>
  <IsTruncated>false</IsTruncated>
  <Contents>
    <Key>object001</Key>
    <LastModified>2015-07-01T00:32:16.482Z</LastModified>
    <ETag>"2fa3bcaaec668adc5da177e67a122d7c"</ETag>
    <Size>12041</Size>
    <Owner>
      <ID>b4bf1b36d9ca43d984fbcb9491b6fce9</ID>
      <DisplayName>ObjectOwnerName</DisplayName>
    </Owner>
    <StorageClass>STANDARD</StorageClass>
  </Contents>
</ListBucketResult>

Sample Request: Listing Some Objects

Assume that you have a bucket examplebucket that contains objects newfile, obj001, obj002, and obs001. If you want to list only object obj002, the request message is as follows:

GET /?marker=obj001&prefix=obj HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: WED, 01 Jul 2015 02:28:25 GMT
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:KiyoYze4pmRNPYfmlXBfRTVxt8c=

Sample Response: Listing Some Objects

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: BF260000016435D758FBA857E0801874
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCShn/xAyk/xHBX6qgGSB36WXrbco0X80
Content-Type: application/xml
Date: WED, 01 Jul 2015 02:29:48 GMT
Content-Length: 707

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ListBucketResult xmlns="http://obs.example.com/doc/2015-06-30/">
<Name>examplebucket</Name>
<Prefix>obj</Prefix>
<Marker>obj001</Marker>
<MaxKeys>1000</MaxKeys>
<IsTruncated>false</IsTruncated>
  <Contents>
    <Key>obj002</Key>
    <LastModified>2015-07-01T02:11:19.775Z</LastModified>
    <ETag>"a72e382246ac83e86bd203389849e71d"</ETag>
    <Size>9</Size>
    <Owner>
      <ID>b4bf1b36d9ca43d984fbcb9491b6fce9</ID>
      <DisplayName>ObjectOwnerName</DisplayName>
    </Owner>
    <StorageClass>STANDARD</StorageClass>
  </Contents>
</ListBucketResult>

Sample Request: Listing Object Versions

GET /?versions HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: WED, 01 Jul 2015 02:29:45 GMT
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:iZeDESIMxBK2YODk7vIeVpyO8DI=

Sample Response: Listing Object Versions

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: BF260000016435D758FBA857E0801874
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCShn/xAyk/xHBX6qgGSB36WXrbco0X80
Content-Type: application/xml
Date: WED, 01 Jul 2015 02:29:48 GMT
Content-Length: 707

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ListVersionsResult xmlns="http://obs.example.com/doc/2015-06-30/">
 <Name>bucket02</Name>
  <Prefix/>
  <KeyMarker/>
  <VersionIdMarker/>
  <MaxKeys>1000</MaxKeys>
  <IsTruncated>false</IsTruncated>
  <Version>
    <Key>object001</Key>
    <VersionId>00011000000000013F16000001643A22E476FFFF9046024ECA3655445346485a</VersionId>
    <IsLatest>true</IsLatest>
    <LastModified>2015-07-01T00:32:16.482Z</LastModified>
    <ETag>"2fa3bcaaec668adc5da177e67a122d7c"</ETag>
    <Size>12041</Size>
    <Owner>
      <ID>b4bf1b36d9ca43d984fbcb9491b6fce9</ID>
      <DisplayName>ObjectOwnerName</DisplayName>
    </Owner>
    <StorageClass>STANDARD</StorageClass>
  </Version>
</ListVersionsResult>