All Products
Search
Document Center

Object Storage Service:Query object metadata by using OSS SDK for Go

Last Updated:Feb 01, 2024

By default, when you call the HeadObject operation on an Object Storage Service (OSS) object in a versioning-enabled bucket, the metadata of only the current version of the object is returned. If you specify a version ID in the request, OSS returns the metadata of the specified version of the object.

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 Initialization.

  • To query object metadata, you must have the oss:GetObject permission. For more information, see Attach a custom policy to a RAM user.

Examples

The following sample code provides an example on how to query the metadata of a specific version of an object:

package main

import (
	"fmt"
	"github.com/aliyun/aliyun-oss-go-sdk/oss"
	"os"
)

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 {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	// 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. 
	client, err := oss.New("yourEndpoint", "", "", oss.SetCredentialsProvider(&provider))
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	// Specify the full path of the object. Do not include the bucket name in the full path. Example: exampleobject.txt. 
	objectName := "exampleobject.txt"

	// Specify the name of the bucket in which the object is stored. Example: examplebucket. 
	bucket, err := client.Bucket("examplebucket")
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}

	// Query part of the metadata of the specified version of the object. 
	// Specify the version ID of the object. 
	props, err := bucket.GetObjectMeta(objectName, oss.VersionId("youObjectVersionId"))
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	fmt.Println("Object Meta:", props)

	// Query all metadata of the specified version of the object. 
	// Specify the version ID of the object. 
	props, err = bucket.GetObjectDetailedMeta(objectName, oss.VersionId("youObjectVersionId"))
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	fmt.Println("Object Meta:", props)
}

References

  • For the complete sample code that is used to query object metadata, visit GitHub.

  • For more information about the API operation that you can call to query object metadata, see GetObjectMeta.