Object Storage Service:Use MetaSearch to query objects in OSS based on metadata properties

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.MetaQueryMode;

public class OpenMetaQuery {
    public static void main(String[] args) throws com.aliyuncs.exceptions.ClientException {
        // In this example, the endpoint of the China (Hangzhou) region is used.
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Specify the name of the bucket. Example: examplebucket.
        String bucketName = "examplebucket";
        // 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.
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 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.
        String region = "cn-hangzhou";

        // Create an OSSClient instance.
        //Call the shutdown method to release associated resources when the OSSClient instance is no longer used.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            // Enable the MetaSearch feature.
            ossClient.openMetaQuery(bucketName);
        } catch (OSSException oe) {
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Error Message: " + ce.getMessage());
        } finally {
            // Shut down the OSSClient instance.
            if(ossClient != null){
                ossClient.shutdown();
            }
        }
    }
}

import argparse
import alibabacloud_oss_v2 as oss

# Create a command-line parameter parser and describe the purpose of the script.
parser = argparse.ArgumentParser(description="open meta query sample")
# Specify the --region parameter to indicate the region in which the bucket is located. This parameter is required.
parser.add_argument('--region', help='The region in which the bucket is located.', required=True)
# Specify the --bucket parameter to indicate the bucket. This parameter is required.
parser.add_argument('--bucket', help='The name of the bucket.', required=True)
# Specify the --endpoint parameter to indicate the endpoint for accessing OSS. This parameter is required.
parser.add_argument('--endpoint', help='The domain names that other services can use to access OSS')

def main():
    # Parse the command-line arguments.
    args = parser.parse_args()

    # From the environment variables, load the authentication information required to access OSS.
    credentials_provider = oss.credentials.EnvironmentVariableCredentialsProvider()

    # Use the default configuration of the SDK.
    cfg = oss.config.load_default()
    # Specify the credential provider.
    cfg.credentials_provider = credentials_provider
    # Set the region to the one provided from the command line.
    cfg.region = args.region
    # If a custom endpoint is provided, update the endpoint attribute of the cfg object with the provided endpoint.
    if args.endpoint is not None:
        cfg.endpoint = args.endpoint

    # Create an OSS client.
    client = oss.Client(cfg)

    # Initiate a request to enable metadata-based query.
    result = client.open_meta_query(oss.OpenMetaQueryRequest(
            bucket=args.bucket,
    ))

    # Display the HTTP status code and request ID.
    print(f'status code: {result.status_code},'
          f' request id: {result.request_id},'
          )

# Call the main function when the script is directly run.
if __name__ == "__main__":
    main()

package main

import (
	"context"
	"flag"   
	"log"     

	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss"          
	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss/credentials" 
)

var (
	region     string // Specify a variable to store the region information obtained from the command lines.
	bucketName string // Specify a variable to store the bucket name obtained from the command lines.
)

// The init function is executed before the main function to initialize the program.
func init() {
	// Use a command line parameter to specify the region.
	flag.StringVar(&region, "region", "", "The region in which the bucket is located.")
	// Use a command line parameter to specify the bucket name.
	flag.StringVar(&bucketName, "bucket", "", "The name of the bucket.")
}

func main() {
	flag.Parse() // Parse command line parameters.

	// Check if the bucket name is specified. If not, the program outputs default parameters and terminates.
	if len(bucketName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, bucket name required") // Log the error message and terminate the program.
	}

	// Check whether the region is specified. If the region is not specified, output the default parameters and exit the program.
	if len(region) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, region required") // Log the error message and terminate the program.
	}

	// Create and configure a client and use environment variables to pass the credential provider.
	cfg := oss.LoadDefaultConfig().
		WithCredentialsProvider(credentials.NewEnvironmentVariableCredentialsProvider()).
		WithRegion(region)

	client := oss.NewClient(cfg) // Use the client configurations to create a new OSSClient instance.

	// Create an OpenMetaQuery request to enable the metadata management feature for a specific bucket.
	request := &oss.OpenMetaQueryRequest{
		Bucket: oss.Ptr(bucketName), // Specify the name of the bucket.
	}
	result, err := client.OpenMetaQuery(context.TODO(), request) // Execute the request to enable the metadata management feature for the bucket.
	if err != nil {
		log.Fatalf("failed to open meta query %v", err) // If an error occurs, record the error message and terminate the program.
	}

	log.Printf("open meta query result:%#v\n", result) // Display the result.
}

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.*;
import java.util.ArrayList;
import java.util.List;

public class DoMetaQuery {
    public static void main(String[] args) throws Exception {
        // In this example, the endpoint of the China (Hangzhou) region is used.
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Specify the name of the bucket. Example: examplebucket.
        String bucketName = "examplebucket";
        // 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.
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // 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.
        String region = "cn-hangzhou";

        // Create an OSSClient instance.
        // Call the shutdown method to release associated resources when the OSSClient instance is no longer used.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            // Query objects that meet specific conditions and return objects based on specific fields and in the specified sorting order.
            int maxResults = 20;
            // Query objects that are smaller than 1,048,576 bytes in size, return up to 20 objects at a time, and sort the objects in ascending order.
            String query = "{\"Field\": \"Size\",\"Value\": \"1048576\",\"Operation\": \"lt\"}";
            String sort = "Size";
            DoMetaQueryRequest doMetaQueryRequest = new DoMetaQueryRequest(bucketName, maxResults, query, sort);
            Aggregation aggregationRequest = new Aggregation();
            Aggregations aggregations = new Aggregations();
            List<Aggregation> aggregationList = new ArrayList<Aggregation>();
            // Specify the name of the field that is used in the aggregate operation.
            aggregationRequest.setField("Size");
            // Specify the operator that is used in the aggregate operation. max indicates the maximum value.
            aggregationRequest.setOperation("max");
            aggregationList.add(aggregationRequest);
            aggregations.setAggregation(aggregationList);

            // Specify the aggregate operation.
            doMetaQueryRequest.setAggregations(aggregations);
            doMetaQueryRequest.setOrder(SortOrder.ASC);
            DoMetaQueryResult doMetaQueryResult = ossClient.doMetaQuery(doMetaQueryRequest);
            if(doMetaQueryResult.getFiles() != null){
                for(ObjectFile file : doMetaQueryResult.getFiles().getFile()){
                    System.out.println("Filename: " + file.getFilename());
                    // Query the ETag value that is used to identify the content of the object.
                    System.out.println("ETag: " + file.getETag());
                    // Query the access control list (ACL) of the object.
                    System.out.println("ObjectACL: " + file.getObjectACL());
                    // Query the type of the object.
                    System.out.println("OssObjectType: " + file.getOssObjectType());
                    // Query the storage class of the object.
                    System.out.println("OssStorageClass: " + file.getOssStorageClass());
                    // Query the number of tags of the object.
                    System.out.println("TaggingCount: " + file.getOssTaggingCount());
                    if(file.getOssTagging() != null){
                        for(Tagging tag : file.getOssTagging().getTagging()){
                            System.out.println("Key: " + tag.getKey());
                            System.out.println("Value: " + tag.getValue());
                        }
                    }
                    if(file.getOssUserMeta() != null){
                        for(UserMeta meta : file.getOssUserMeta().getUserMeta()){
                            System.out.println("Key: " + meta.getKey());
                            System.out.println("Value: " + meta.getValue());
                        }
                    }
                }
            } else if(doMetaQueryResult.getAggregations() != null){
                for(Aggregation aggre : doMetaQueryResult.getAggregations().getAggregation()){
                    // Query the field by which the aggregation is performed.
                    System.out.println("Field: " + aggre.getField());
                    // Query the aggregation operator.
                    System.out.println("Operation: " + aggre.getOperation());
                    // Query the result of the aggregate operation.
                    System.out.println("Value: " + aggre.getValue());
                    if(aggre.getGroups() != null && aggre.getGroups().getGroup().size() > 0){
                        // Query the value of the aggregation.
                        System.out.println("Groups value: " + aggre.getGroups().getGroup().get(0).getValue());
                        // Query the total number of the aggregations.
                        System.out.println("Groups count: " + aggre.getGroups().getGroup().get(0).getCount());
                    }
                }
            } else {
                System.out.println("NextToken: " + doMetaQueryResult.getNextToken());
            }
        } catch (OSSException oe) {
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Error Message: " + ce.getMessage());
        } finally {
            // Shut down the OSSClient instance.
            ossClient.shutdown();
        }
    }
}

import argparse
import alibabacloud_oss_v2 as oss

# Create a command-line parameter parser for parsing arguments from the command line.
parser = argparse.ArgumentParser(description="do meta query sample")
parser.add_argument('--region', help='The region in which the bucket is located.', required=True)
parser.add_argument('--bucket', help='The name of the bucket.', required=True)
parser.add_argument('--endpoint', help='The domain names that other services can use to access OSS')

def main():
    # Parse the command-line arguments.
    args = parser.parse_args()

    # Obtain access credentials from environment variables.
    credentials_provider = oss.credentials.EnvironmentVariableCredentialsProvider()

    # Use the default configuration of the SDK.
    cfg = oss.config.load_default()
    # Specify the credential provider.
    cfg.credentials_provider = credentials_provider
    # Set the region to the one provided from the command line.
    cfg.region = args.region
    # If a custom endpoint is provided, update the endpoint attribute of the cfg object with the provided endpoint.
    if args.endpoint is not None:
        cfg.endpoint = args.endpoint

    # Create an OSS client.
    client = oss.Client(cfg)

    # Perform the metadata-based query.
    result = client.do_meta_query(oss.DoMetaQueryRequest(
            bucket=args.bucket,  # The bucket that stores the objects to be queried.
            meta_query=oss.MetaQuery(  # Specify query settings.
                aggregations=oss.MetaQueryAggregations(  # Specify aggregatios.
                    aggregations=[  # The aggregation list.
                        oss.MetaQueryAggregation(  # The first aggregation: the total object size.
                            field='Size',
                            operation='sum',
                        ),
                        oss.MetaQueryAggregation(  # The second aggregation: the maximum object size.
                            field='Size',
                            operation='max',
                        )
                    ],
                ),
                next_token='',  # The pagination token.
                max_results=80369,  # The maximum number of entries that can be returned.
                query='{"Field": "Size","Value": "1048576","Operation": "gt"}',  # The query condition.
                sort='Size',  # The sorting field.
                order=oss.MetaQueryOrderType.DESC,  # The sorting order.
            ),
    ))

    # Display the basic response information.
    print(f'status code: {result.status_code},'
          f' request id: {result.request_id},'
          # You can uncomment the one or more of the following lines to display more details.
          # f' files: {result.files},'
          # f' file: {result.files.file},'
          # f' file modified time: {result.files.file.file_modified_time},'
          # f' etag: {result.files.file.etag},'
          # f' server side encryption: {result.files.file.server_side_encryption},'
          # f' oss tagging count: {result.files.file.oss_tagging_count},'
          # f' oss tagging: {result.files.file.oss_tagging},'
          # f' key: {result.files.file.oss_tagging.taggings[0].key},'
          # f' value: {result.files.file.oss_tagging.taggings[0].value},'
          # f' key: {result.files.file.oss_tagging.taggings[1].key},'
          # f' value: {result.files.file.oss_tagging.taggings[1].value},'
          # f' oss user meta: {result.files.file.oss_user_meta},'
          # f' key: {result.files.file.oss_user_meta.user_metas[0].key},'
          # f' value: {result.files.file.oss_user_meta.user_metas[0].value},'
          # f' key: {result.files.file.oss_user_meta.user_metas[1].key},'
          # f' value: {result.files.file.oss_user_meta.user_metas[1].value},'
          # f' filename: {result.files.file.filename},'
          # f' size: {result.files.file.size},'
          # f' oss object type: {result.files.file.oss_object_type},'
          # f' oss storage class: {result.files.file.oss_storage_class},'
          # f' object acl: {result.files.file.object_acl},'
          # f' oss crc64: {result.files.file.oss_crc64},'
          # f' server side encryption customer algorithm: {result.files.file.server_side_encryption_customer_algorithm},'
          # f' aggregations: {result.aggregations},'
          f' field: {result.aggregations.aggregations[0].field},'
          f' operation: {result.aggregations.aggregations[0].operation},'
          f' field: {result.aggregations.aggregations[1].field},'
          f' operation: {result.aggregations.aggregations[1].operation},'
          f' next token: {result.next_token},'
    )

    # If matched objects are found, display tags and user metadata.
    if result.files:
        if result.files.file.oss_tagging.taggings:
            for r in result.files.file.oss_tagging.taggings:
                print(f'result: key: {r.key}, value: {r.value}')
        if result.files.file.oss_user_meta.user_metas:
            for r in result.files.file.oss_user_meta.user_metas:
                print(f'result: key: {r.key}, value: {r.value}')
    # Display all aggregations.
    if result.aggregations.aggregations:
        for r in result.aggregations.aggregations:
            print(f'result: field: {r.field}, operation: {r.operation}')

if __name__ == "__main__":
    main()