This topic describes how to list objects in a versioning-enabled bucket, such as listing all objects, objects whose names contain a specified prefix, and objects and subdirectories in a specified directory.
Usage notes
In this topic, the public endpoint of the China (Hangzhou) region is used. If you want to access OSS from other Alibaba Cloud services in the same region as OSS, use an internal endpoint. For more information about OSS regions and endpoints, see Regions, endpoints and open ports.
In this topic, access credentials are obtained from environment variables. For more information about how to configure access credentials, see Configure access credentials.
In this topic, an OSSClient instance is created by using an OSS endpoint. If you want to create an OSSClient instance by using custom domain names or Security Token Service (STS), see Initialization.
To list objects, you must have the oss:ListObjectVersions permission. For more information, see Attach a custom policy to a RAM user.
Scenarios
The following figure shows the directories and objects in a bucket named examplebucket.
examplebucket
└── fun
└── exampleobject.jpg
└── examplefile.txt
└── destfolder
└── image1.jpg
└── image2.png
└── srcfile.txt
└── oss.jpg
The following sections describe how to list different objects by specifying conditions.
For more information about the parameters that you can configure when you list objects, see ListObjectVersions (GetBucketVersions).
Sample code
The following code provides an example on how to list the versions of all objects including delete markers in a specified bucket:
package main
import (
"log"
"github.com/aliyun/aliyun-oss-go-sdk/oss"
)
func main() {
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
provider, err := oss.NewEnvironmentVariableCredentialsProvider()
if err != nil {
log.Fatalf("Failed to create credentials provider: %v", err)
}
// Create an OSSClient instance.
// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify your actual endpoint.
// Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. Specify the actual region.
clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
clientOptions = append(clientOptions, oss.Region("yourRegion"))
// Specify the version of the signature algorithm.
clientOptions = append(clientOptions, oss.AuthVersion(oss.AuthV4))
client, err := oss.New("yourEndpoint", "", "", clientOptions...)
if err != nil {
log.Fatalf("Failed to create OSS client: %v", err)
}
// Specify the name of the bucket.
bucketName := "examplebucket"
bucket, err := client.Bucket(bucketName)
if err != nil {
log.Fatalf("Failed to get bucket '%s': %v", bucketName, err)
}
// List the versions of all objects including delete markers in the bucket.
keyMarker := oss.KeyMarker("")
versionIdMarker := oss.VersionIdMarker("")
for {
lor, err := bucket.ListObjectVersions(keyMarker, versionIdMarker)
if err != nil {
log.Fatalf("Failed to list object versions: %v", err)
}
// Display the version IDs of the objects.
for _, objVersion := range lor.ObjectVersions {
log.Printf("Versionid: %s", objVersion.VersionId)
log.Printf("Key: %s", objVersion.Key)
log.Printf("Is Latest: %t", objVersion.IsLatest)
}
// Display the versions of the listed delete markers.
for _, deleteMarker := range lor.ObjectDeleteMarkers {
log.Printf("Delete Marker Versionid: %s", deleteMarker.VersionId)
log.Printf("Delete Marker Key: %s", deleteMarker.Key)
}
// Check whether the required versions are listed. If the versions are incompletely listed, the list operation continues. If the versions are completely listed, the list operation stops.
keyMarker = oss.KeyMarker(lor.NextKeyMarker)
versionIdMarker = oss.VersionIdMarker(lor.NextVersionIdMarker)
if !lor.IsTruncated {
break
}
}
}
Sample response:
Versionid: CAEQChiBgIDHzNPEthciIDYzZGQ5M2VjOTU2ODRmMzA4ZWM4ODk0NjVmMWEx****
Key: fun/
Is Latest true
Versionid: CAEQChiBgID61tnEthciIDNmOGM2MTQ3ZjU1NTQ2MGFhYWJjNjQxMTQxZWZh****
Key: fun/destfolder/
Is Latest true
Versionid: CAEQChiBgMDczt3EthciIDEwYjliZmQ4MDNiMDQ2Njk4YWMxM2NhM2E5NzQ3****
Key: fun/destfolder/image1.jpg
Is Latest true
Versionid: CAEQChiBgIDszt3EthciIGU5OWU0ZTllMGY3NTRmMmU5NzVjZmJkYmE3ZWYy****
Key: fun/destfolder/image2.png
Is Latest true
Versionid: CAEQChiBgICditzEthciIDBiNTg1ZTZkMDRlMzRjNDdiMjRjMTBlOGUzMTM0****
Key: fun/examplefile.txt
Is Latest true
Versionid: CAEQChiBgMC.itzEthciIDEzNWVlYjNhYzNmMjQ4NWM5Nzc2NzllY2FiYmQ3****
Key: fun/exampleobject.jpg
Is Latest true
Versionid: CAEQChiBgIDMgdbEthciIDUyMGI0NmZlNThkODQwY2ZhNmZhNTQ1Njk4ZTdj****
Key: oss.jpg
Is Latest true
Versionid: CAEQChiBgICIgdbEthciIDdlM2Q1YjYxZDIyZDQyMzI4MTRkNzVmYzdiMTBh****
Key: srcfile.txt
Is Latest true
Common scenarios
List the versions of objects whose names contain a specified prefix
The following code provides an example on how to list the versions of objects whose names contain a specified prefix:
package main
import (
"log"
"github.com/aliyun/aliyun-oss-go-sdk/oss"
)
func main() {
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
provider, err := oss.NewEnvironmentVariableCredentialsProvider()
if err != nil {
log.Fatalf("Failed to create credentials provider: %v", err)
}
// Create an OSSClient instance.
// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify your actual endpoint.
// Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. Specify the actual region.
clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
clientOptions = append(clientOptions, oss.Region("yourRegion"))
// Specify the version of the signature algorithm.
clientOptions = append(clientOptions, oss.AuthVersion(oss.AuthV4))
client, err := oss.New("yourEndpoint", "", "", clientOptions...)
if err != nil {
log.Fatalf("Failed to create OSS client: %v", err)
}
// Specify the name of the bucket.
bucketName := "examplebucket"
bucket, err := client.Bucket(bucketName)
if err != nil {
log.Fatalf("Failed to get bucket '%s': %v", bucketName, err)
}
// Specify the Prefix parameter to list the versions of objects whose names contain the fun prefix.
prefix := oss.Prefix("fun")
keyMarker := oss.KeyMarker("")
versionIdMarker := oss.VersionIdMarker("")
for {
lor, err := bucket.ListObjectVersions(prefix, keyMarker, versionIdMarker)
if err != nil {
log.Fatalf("Failed to list object versions: %v", err)
}
// Display the version IDs of the objects.
for _, objVersion := range lor.ObjectVersions {
log.Printf("VersionId: %s", objVersion.VersionId)
log.Printf("Key: %s", objVersion.Key)
log.Printf("Is Latest: %t", objVersion.IsLatest)
}
// Check whether the required versions are listed. If the versions are incompletely listed, the list operation continues. If the versions are completely listed, the list operation stops.
keyMarker = oss.KeyMarker(lor.NextKeyMarker)
versionIdMarker = oss.VersionIdMarker(lor.NextVersionIdMarker)
if !lor.IsTruncated {
break
}
}
}
Returned results:
Versionid: CAEQChiBgIDHzNPEthciIDYzZGQ5M2VjOTU2ODRmMzA4ZWM4ODk0NjVmMWEx****
Key: fun/
Is Latest true
Versionid: CAEQChiBgID61tnEthciIDNmOGM2MTQ3ZjU1NTQ2MGFhYWJjNjQxMTQxZWZh****
Key: fun/destfolder/
Is Latest true
Versionid: CAEQChiBgMDczt3EthciIDEwYjliZmQ4MDNiMDQ2Njk4YWMxM2NhM2E5NzQ3****
Key: fun/destfolder/image1.jpg
Is Latest true
Versionid: CAEQChiBgIDszt3EthciIGU5OWU0ZTllMGY3NTRmMmU5NzVjZmJkYmE3ZWYy****
Key: fun/destfolder/image2.png
Is Latest true
Versionid: CAEQChiBgICditzEthciIDBiNTg1ZTZkMDRlMzRjNDdiMjRjMTBlOGUzMTM0****
Key: fun/examplefile.txt
Is Latest true
Versionid: CAEQChiBgMC.itzEthciIDEzNWVlYjNhYzNmMjQ4NWM5Nzc2NzllY2FiYmQ3****
Key: fun/exampleobject.jpg
Is Latest true
List the versions of a specified number of objects
The following code provides an example on how to list the versions of a specified number of objects:
package main
import (
"log"
"github.com/aliyun/aliyun-oss-go-sdk/oss"
)
func main() {
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
provider, err := oss.NewEnvironmentVariableCredentialsProvider()
if err != nil {
log.Fatalf("Failed to create credentials provider: %v", err)
}
// Create an OSSClient instance.
// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify your actual endpoint.
// Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. Specify the actual region.
clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
clientOptions = append(clientOptions, oss.Region("yourRegion"))
// Specify the version of the signature algorithm.
clientOptions = append(clientOptions, oss.AuthVersion(oss.AuthV4))
client, err := oss.New("yourEndpoint", "", "", clientOptions...)
if err != nil {
log.Fatalf("Failed to create OSS client: %v", err)
}
// Specify the name of the bucket.
bucketName := "examplebucket"
bucket, err := client.Bucket(bucketName)
if err != nil {
log.Fatalf("Failed to get bucket '%s': %v", bucketName, err)
}
// Specify the MaxKeys parameter to list up to four object versions in alphabetical order of the object names.
maxKeys := oss.MaxKeys(4)
keyMarker := oss.KeyMarker("")
versionIdMarker := oss.VersionIdMarker("")
for {
lor, err := bucket.ListObjectVersions(maxKeys, keyMarker, versionIdMarker)
if err != nil {
log.Fatalf("Failed to list object versions: %v", err)
}
// Display the version IDs of the objects.
for _, objVersion := range lor.ObjectVersions {
log.Printf("Versionid: %s", objVersion.VersionId)
log.Printf("Key: %s", objVersion.Key)
log.Printf("Is Latest: %t", objVersion.IsLatest)
}
// Check whether the required versions are listed. If the versions are incompletely listed, the list operation continues. If the versions are completely listed, the list operation stops.
keyMarker = oss.KeyMarker(lor.NextKeyMarker)
versionIdMarker = oss.VersionIdMarker(lor.NextVersionIdMarker)
if !lor.IsTruncated {
break
}
}
}
Sample response:
Versionid: CAEQChiBgIDHzNPEthciIDYzZGQ5M2VjOTU2ODRmMzA4ZWM4ODk0NjVmMWEx****
Key: fun/
Is Latest true
Versionid: CAEQChiBgID61tnEthciIDNmOGM2MTQ3ZjU1NTQ2MGFhYWJjNjQxMTQxZWZh****
Key: fun/destfolder/
Is Latest true
Versionid: CAEQChiBgMDczt3EthciIDEwYjliZmQ4MDNiMDQ2Njk4YWMxM2NhM2E5NzQ3****
Key: fun/destfolder/image1.jpg
Is Latest true
Versionid: CAEQChiBgIDszt3EthciIGU5OWU0ZTllMGY3NTRmMmU5NzVjZmJkYmE3ZWYy****
Key: fun/destfolder/image2.png
Is Latest true
List the versions of all objects by page
The following code provides an example on how to list the versions of all objects by page:
package main
import (
"log"
"github.com/aliyun/aliyun-oss-go-sdk/oss"
)
func main() {
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
provider, err := oss.NewEnvironmentVariableCredentialsProvider()
if err != nil {
log.Fatalf("Failed to create credentials provider: %v", err)
}
// Create an OSSClient instance.
// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify your actual endpoint.
// Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. Specify the actual region.
clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
clientOptions = append(clientOptions, oss.Region("yourRegion"))
// Specify the version of the signature algorithm.
clientOptions = append(clientOptions, oss.AuthVersion(oss.AuthV4))
client, err := oss.New("yourEndpoint", "", "", clientOptions...)
if err != nil {
log.Fatalf("Failed to create OSS client: %v", err)
}
// Specify the name of the bucket.
bucketName := "examplebucket"
bucket, err := client.Bucket(bucketName)
if err != nil {
log.Fatalf("Failed to get bucket '%s': %v", bucketName, err)
}
// List the versions of all objects in the bucket by page.
keyMarker := oss.KeyMarker("")
// Specify the MaxKeys parameter to list up to four object versions in alphabetical order of the object names.
maxKeys := oss.MaxKeys(4)
versionIdMarker := oss.VersionIdMarker("")
for {
lor, err := bucket.ListObjectVersions(maxKeys, keyMarker, versionIdMarker)
if err != nil {
log.Fatalf("Failed to list object versions: %v", err)
}
// Display the version IDs of the objects.
for _, objVersion := range lor.ObjectVersions {
log.Printf("Versionid: %s", objVersion.VersionId)
log.Printf("Key: %s", objVersion.Key)
log.Printf("Is Latest: %t", objVersion.IsLatest)
}
log.Println("---------------")
// Check whether the required versions are listed. If the versions are incompletely listed, the list operation continues. If the versions are completely listed, the list operation stops.
if lor.IsTruncated {
keyMarker = oss.KeyMarker(lor.NextKeyMarker)
versionIdMarker = oss.VersionIdMarker(lor.NextVersionIdMarker)
} else {
break
}
}
}
Sample response:
Versionid: CAEQChiBgIDHzNPEthciIDYzZGQ5M2VjOTU2ODRmMzA4ZWM4ODk0NjVmMWEx****
Key: fun/
Is Latest true
Versionid: CAEQChiBgID61tnEthciIDNmOGM2MTQ3ZjU1NTQ2MGFhYWJjNjQxMTQxZWZh****
Key: fun/destfolder/
Is Latest true
Versionid: CAEQChiBgMDczt3EthciIDEwYjliZmQ4MDNiMDQ2Njk4YWMxM2NhM2E5NzQ3****
Key: fun/destfolder/image1.jpg
Is Latest true
Versionid: CAEQChiBgIDszt3EthciIGU5OWU0ZTllMGY3NTRmMmU5NzVjZmJkYmE3ZWYy****
Key: fun/destfolder/image2.png
Is Latest true
---------------
Versionid: CAEQChiBgICditzEthciIDBiNTg1ZTZkMDRlMzRjNDdiMjRjMTBlOGUzMTM0****
Key: fun/examplefile.txt
Is Latest true
Versionid: CAEQChiBgMC.itzEthciIDEzNWVlYjNhYzNmMjQ4NWM5Nzc2NzllY2FiYmQ3****
Key: fun/exampleobject.jpg
Is Latest true
Versionid: CAEQChiBgIDMgdbEthciIDUyMGI0NmZlNThkODQwY2ZhNmZhNTQ1Njk4ZTdj****
Key: oss.jpg
Is Latest true
Versionid: CAEQChiBgICIgdbEthciIDdlM2Q1YjYxZDIyZDQyMzI4MTRkNzVmYzdiMTBh****
Key: srcfile.txt
Is Latest true
---------------
Reference
For more information about the API operation that you call to list the versions of all objects in a bucket, see ListObjectVersions.