Object Storage Service:Manage object ACLs

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 OSS 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 Initialization.

• To configure the ACL for an object, you must have the oss:PutObjectAcl permission. To query object ACLs, you must have the oss:GetObjectAcl permission. For more information, see Attach a custom policy to a RAM user.

Object ACLs

The following table describes the ACLs that you can configure for an object.

The ACL of an object takes precedence over the ACL of the bucket in which the object is stored. For example, if the ACL of a bucket is private and the ACL of an object that is stored in the bucket is public read/write, all users are granted the read and write permissions on the object. If the ACL of an object is not configured, the ACL of the object is the same as the ACL of the bucket in which the object is stored.

Sample code

The following code provides an example on how to configure and query the ACL of an object:

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 your bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. Specify your actual endpoint.
	clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
	clientOptions = append(clientOptions, oss.Region("yourRegion"))
	// Specify 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 name of the bucket. 
	bucketName := "yourBucketName"
	bucket, err := client.Bucket(bucketName)
	if err != nil {
		log.Fatalf("Failed to get bucket '%s': %v", bucketName, err)
	}

	// Configure the ACL of the object. 
	// Specify the full path of the object. Do not include the bucket name in the full path. 
	objectName := "yourObjectName"
	err = bucket.SetObjectACL(objectName, oss.ACLPublicReadWrite)
	if err != nil {
		log.Fatalf("Failed to set object ACL for '%s': %v", objectName, err)
	}

	// Query the ACL of the object. 
	aclRes, err := bucket.GetObjectACL(objectName)
	if err != nil {
		log.Fatalf("Failed to get object ACL for '%s': %v", objectName, err)
	}

	log.Printf("Object ACL for '%s': %s", objectName, aclRes.ACL)
}

References

• For the complete sample code that is used for object ACL management, visit GitHub.

• For more information about the API operation that you can call to configure the ACL of an object, see SetObjectACL

• For more information about the API operation that you can call to query the ACL of an object, see GetObjectACL.