When versioning is enabled for a bucket, you can list all objects in the bucket, objects with a specified prefix, or 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 and endpoints.
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 Configure OSSClient instances.
To list objects, you must have the oss:ListObjectVersions permission. For more information, see Attach a custom policy to a RAM user.
Scenarios
Assume that you have a bucket named examplebucket. The file structure of the bucket is as follows:
examplebucket
└── fun
└── exampleobject.jpg
└── examplefile.txt
└── destfolder
└── image1.jpg
└── image2.png
└── srcfile.txt
└── oss.jpg
The following examples show how to obtain different results by setting different listing parameters for examplebucket.
For more information about the parameters used to list objects, see ListObjectVersions (GetBucketVersions).
Sample code
The following code shows how to list the version information for 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 this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set.
provider, err := oss.NewEnvironmentVariableCredentialsProvider()
if err != nil {
log.Fatalf("Failed to create credentials provider: %v", err)
}
// Create an OSSClient instance.
// Set yourEndpoint to the endpoint of the bucket. For example, if the bucket is in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. For other regions, specify the actual endpoint.
// Set yourRegion to the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set the region to cn-hangzhou. For other regions, specify the actual region.
clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
clientOptions = append(clientOptions, oss.Region("yourRegion"))
// Set the signature version.
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 bucket name.
bucketName := "examplebucket"
bucket, err := client.Bucket(bucketName)
if err != nil {
log.Fatalf("Failed to get bucket '%s': %v", bucketName, err)
}
// List all objects, including delete markers.
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)
}
// View the version information 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)
}
// View the version information of the 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 list result is complete. If the result is incomplete, continue the listing. If the result is complete, exit the loop.
keyMarker = oss.KeyMarker(lor.NextKeyMarker)
versionIdMarker = oss.VersionIdMarker(lor.NextVersionIdMarker)
if !lor.IsTruncated {
break
}
}
}
Result:
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 version information of objects with a specified prefix
The following code shows how to list the version information for objects with 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 this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set.
provider, err := oss.NewEnvironmentVariableCredentialsProvider()
if err != nil {
log.Fatalf("Failed to create credentials provider: %v", err)
}
// Create an OSSClient instance.
// Set yourEndpoint to the endpoint of the bucket. For example, if the bucket is in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. For other regions, specify the actual endpoint.
// Set yourRegion to the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set the region to cn-hangzhou. For other regions, specify the actual region.
clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
clientOptions = append(clientOptions, oss.Region("yourRegion"))
// Set the signature version.
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 bucket name.
bucketName := "examplebucket"
bucket, err := client.Bucket(bucketName)
if err != nil {
log.Fatalf("Failed to get bucket '%s': %v", bucketName, err)
}
// Use the Prefix parameter to list 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)
}
// View the version information 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 list result is complete. If the result is incomplete, continue the listing. If the result is complete, exit the loop.
keyMarker = oss.KeyMarker(lor.NextKeyMarker)
versionIdMarker = oss.VersionIdMarker(lor.NextVersionIdMarker)
if !lor.IsTruncated {
break
}
}
}
Result:
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 version information of a specified number of objects
The following code shows how to list the version information for 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 this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set.
provider, err := oss.NewEnvironmentVariableCredentialsProvider()
if err != nil {
log.Fatalf("Failed to create credentials provider: %v", err)
}
// Create an OSSClient instance.
// Set yourEndpoint to the endpoint of the bucket. For example, if the bucket is in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. For other regions, specify the actual endpoint.
// Set yourRegion to the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set the region to cn-hangzhou. For other regions, specify the actual region.
clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
clientOptions = append(clientOptions, oss.Region("yourRegion"))
// Set the signature version.
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 bucket name.
bucketName := "examplebucket"
bucket, err := client.Bucket(bucketName)
if err != nil {
log.Fatalf("Failed to get bucket '%s': %v", bucketName, err)
}
// Use the MaxKeys parameter to specify that a maximum of four results are returned in alphabetical order of 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)
}
// View the version information 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 list result is complete. If the result is incomplete, continue the listing. If the result is complete, exit the loop.
keyMarker = oss.KeyMarker(lor.NextKeyMarker)
versionIdMarker = oss.VersionIdMarker(lor.NextVersionIdMarker)
if !lor.IsTruncated {
break
}
}
}
Result:
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 version information of all objects by page
The following code shows how to list object versions 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 this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set.
provider, err := oss.NewEnvironmentVariableCredentialsProvider()
if err != nil {
log.Fatalf("Failed to create credentials provider: %v", err)
}
// Create an OSSClient instance.
// Set yourEndpoint to the endpoint of the bucket. For example, if the bucket is in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. For other regions, specify the actual endpoint.
// Set yourRegion to the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set the region to cn-hangzhou. For other regions, specify the actual region.
clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
clientOptions = append(clientOptions, oss.Region("yourRegion"))
// Set the signature version.
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 bucket name.
bucketName := "examplebucket"
bucket, err := client.Bucket(bucketName)
if err != nil {
log.Fatalf("Failed to get bucket '%s': %v", bucketName, err)
}
// List all objects by page.
keyMarker := oss.KeyMarker("")
// Use the MaxKeys parameter to specify that a maximum of four results are returned in alphabetical order of 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)
}
// View the version information 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 list result is complete. If the result is incomplete, continue the listing. If the result is complete, exit the loop.
if lor.IsTruncated {
keyMarker = oss.KeyMarker(lor.NextKeyMarker)
versionIdMarker = oss.VersionIdMarker(lor.NextVersionIdMarker)
} else {
break
}
}
}
Result:
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
---------------