Object Storage Service:Download objects by using presigned URLs

Java

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.model.GeneratePresignedUrlRequest;
import java.net.URL;
import java.util.*;
import java.util.Date;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 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 name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Example: exampleobject.txt. Do not include the bucket name in the full path of the object. 
        String objectName = "exampleobject.txt";
        // Specify the version ID of the object. 
        String versionId = "CAEQARiBgID8rumR2hYiIGUyOTAyZGY2MzU5MjQ5ZjlhYzQzZjNlYTAyZDE3****";
        // 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. 
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);        
        OSS ossClient = OSSClientBuilder.create()
        .endpoint(endpoint)
        .credentialsProvider(credentialsProvider)
        .clientConfiguration(clientBuilderConfiguration)
        .region(region)               
        .build();

        try {
            // Create a request. 
            GeneratePresignedUrlRequest generatePresignedUrlRequest = new GeneratePresignedUrlRequest(bucketName, objectName);
            // Set HttpMethod to GET. 
            generatePresignedUrlRequest.setMethod(HttpMethod.GET);
            // Specify the validity period of the presigned URL. Unit: milliseconds. In this example, the validity period is 1 hour. 
            Date expiration = new Date(new Date().getTime() + 3600 * 1000L);
            generatePresignedUrlRequest.setExpiration(expiration);
            // Specify the version ID of the object. 
            Map<String, String> queryParam = new HashMap<String, String>();
            queryParam.put("versionId", versionId);
            generatePresignedUrlRequest.setQueryParameter(queryParam);
            // Generate a presigned URL. 
            URL url = ossClient.generatePresignedUrl(generatePresignedUrlRequest);
            System.out.println(url);
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            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("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

Python

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="presign get object sample")

# Specify the --region parameter, which specifies the region in which the bucket is located. This command line 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 name of the bucket in which the object is stored. This parameter is required.
parser.add_argument('--bucket', help='The name of the bucket.', required=True)
# Specify the --endpoint parameter, which specifies the endpoint that other services can use to access OSS. This command line parameter is optional.
parser.add_argument('--endpoint', help='The domain names that other services can use to access OSS')
# Specify the --key parameter, which specifies the name of the object. This command line parameter is required.
parser.add_argument('--key', help='The name of the object.', required=True)

def main():
    # Parse the command line parameters to obtain the values specified by the user.
    args = parser.parse_args()

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

    # Use the default configurations of the SDK to create a configuration object and specify the credential provider.
    cfg = oss.config.load_default()
    cfg.credentials_provider = credentials_provider
    
    # Specify the region attribute of the configuration object based on the command line parameters provided by the user.
    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

    # Use the preceding configuration to initialize the OSSClient instance and allow the instance to interact with OSS.
    client = oss.Client(cfg)

    # Initiate a request to generate a presigned URL.
    # The version_id parameter is optional. You need to specify this parameter only when the object is versioned.
    pre_result = client.presign(
        oss.GetObjectRequest(
            bucket=args.bucket,  # Specify the bucket name.
            key=args.key,        # Specify the object key.
            version_id='yourVersionId'  # If applicable, specify the version ID of the object.
        )
    )

    # Display the HTTP method, expiration time, and presigned URL.
    print(f'method: {pre_result.method},'
          f' expiration: {pre_result.expiration.strftime("%Y-%m-%dT%H:%M:%S.000Z")},'
          f' url: {pre_result.url}'
    )

    # Display the signed headers.
    for key, value in pre_result.signed_headers.items():
        print(f'signed headers key: {key}, signed headers value: {value}')

# Call the main function to start the processing logic when the script is directly run.
if __name__ == "__main__":
    main()  # Script entry point, program flow starts here

Go

package main

import (
	"context"
	"flag"
	"log"
	"time"

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

// Specify the global variables.
var (
	region: string; // The region in which the bucket is located.
	bucketName string // The name of the bucket.
	objectName string // The name of the object.
)

// Specify the init function used to initialize command line parameters.
func init() {
	flag.StringVar(&region, "region", "", "The region in which the bucket is located.")
	flag.StringVar(&bucketName, "bucket", "", "The name of the bucket.")
	flag.StringVar(&objectName, "object", "", "The name of the object.")
}

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

	// Check whether the bucket name is empty.
	if len(bucketName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, bucket name required")
	}

	// Check whether the region is empty.
	if len(region) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, region required")
	}

	// Check whether the object name is empty.
	if len(objectName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, object name required")
	}

	// Load the default configurations and specify the credential provider and region.
	cfg := oss.LoadDefaultConfig().
		WithCredentialsProvider(credentials.NewEnvironmentVariableCredentialsProvider()).
		WithRegion(region)

	// Create an OSS client.
	client := oss.NewClient(cfg)

	// Generate a presigned URL for the GetObject request.
	result, err := client.Presign(context.TODO(), &oss.GetObjectRequest{
		Bucket:    oss.Ptr(bucketName),
		Key:       oss.Ptr(objectName),
		VersionId: oss.Ptr("yourVersionId"), // Specify the version ID.
	},
		oss.PresignExpires(10*time.Minute),
	)
	if err != nil {
		log.Fatalf("failed to get object presign %v", err)
	}
	log.Printf("get object presign result: %#v\n", result)
	log.Printf("get object url: %#v\n", result.URL)
}

Node.js

const OSS = require("ali-oss");

const client = await new OSS({
  // 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. 
  accessKeyId: process.env.OSS_ACCESS_KEY_ID,
  accessKeySecret: process.env.OSS_ACCESS_KEY_SECRET,
  bucket: 'examplebucket',
  // 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 oss-cn-hangzhou.
  region: 'oss-cn-hangzhou',
  // Set secure to true and use HTTPS to prevent the generated download link from being blocked by the browser.
  secure: true,
  authorizationV4: true
});


// Generate a presigned URL.
const signedUrl = await client.signatureUrlV4('GET', 3600, {
  queries:{
    // Specify the version ID of the object.
    "versionId":'yourVersionId'
  }
}, 'demo.pdf');

PHP

<?php

// Include the autoload file to load dependencies.
require_once __DIR__ . '/../vendor/autoload.php';

use AlibabaCloud\Oss\V2 as Oss;

// Define and describe command-line parameters.
$optsdesc = [
    "region" => ['help' => 'The region in which the bucket is located.', 'required' => True], // (Required) Specify the region in which the bucket is located.
    "endpoint" => ['help' => 'The domain names that other services can use to access OSS.', 'required' => False], // (Optional) Specify the endpoint for accessing OSS.
    "bucket" => ['help' => 'The name of the bucket', 'required' => True], // (Required) Specify the name of the bucket.
    "key" => ['help' => 'The name of the object', 'required' => True], // (Required) Specify the name of the object.
];

// Convert the descriptions to a list of long options required by getopt.
// Add a colon (:) to the end of each parameter to indicate that a value is required.
$longopts = \array_map(function ($key) {
    return "$key:";
}, array_keys($optsdesc));

// Parse the command-line arguments.
$options = getopt("", $longopts);

// Check whether required arguments are missing.
foreach ($optsdesc as $key => $value) {
    if ($value['required'] === True && empty($options[$key])) {
        $help = $value['help']; // Obtain argument description.
        echo "Error: the following arguments are required: --$key, $help" . PHP_EOL;
        exit(1); // Exit the program if a required parameter is missing.
    }
}

// Extract parsed arguments and use them.
$region = $options["region"]; // The region in which the bucket is located.
$bucket = $options["bucket"]; // The name of the bucket.
$key = $options["key"];       // The name of the object.

// Load access credentials from environment variables.
// Use EnvironmentVariableCredentialsProvider to retrieve the AccessKey ID and AccessKey secret from environment variables.
$credentialsProvider = new Oss\Credentials\EnvironmentVariableCredentialsProvider();

// Use the default configuration of the SDK.
$cfg = Oss\Config::loadDefault();
$cfg->setCredentialsProvider($credentialsProvider); // Specify the credential provider.
$cfg->setRegion($region); // Specify the region in which the bucket is located.
if (isset($options["endpoint"])) {
    $cfg->setEndpoint($options["endpoint"]); // Specify the endpoint if one is provided.
}

// Create an OSS client instance.
$client = new Oss\Client($cfg);

$versionId = "yourVersionId"; // Specify the object version to be downloaded. Replace the example value with the actual version ID.

// Create a GetObjectRequest object to download an object.
$request = new Oss\Models\GetObjectRequest(bucket:$bucket, key:$key, versionId: $versionId);

// Call the presign method to generate a presigned request.
$result = $client->presign($request);

// Display the result of the presign operation.
// Display the presigned URL, which can be used to download the specified object.
print(
    'get object presign result:' . var_export($result, true) . PHP_EOL . // The details of the presign result.
    'get object url:' . $result->url . PHP_EOL                           // The presigned URL.
);

Use the OSS console

1. Log on to the OSS console.

2. In the left-side navigation pane, click Buckets. On the Buckets page, click the name of the bucket.

3. In the left-side navigation tree, choose Object Management > Objects.

4. On the Objects page, click the name of the object.

5. In the View Details panel, select the custom domain name that is mapped to the bucket in the Custom Domain Name field, retain the default settings for other parameters, and then click Copy Object URL.

   

Use ossbrowser

You can use ossbrowser to perform the same object-level operations that you can perform in the OSS console. You can follow the on-screen instructions in ossbrowser to obtain a presigned URL. For information about how to download ossbrowser, see ossbrowser 1.0.

1. Use the custom domain name to log on to ossbrowser.

1. Obtain the URL of the object.

Use OSS SDKs

You can use the custom domain name to create an OssClient instance and generate a presigned URL.

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

import java.net.URL;
import java.util.Date;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // Specify a custom domain name. Example: https://static.example.com. 
        String endpoint = "yourCustomEndpoint";
        // Specify the region in which the bucket is located. Example: cn-hangzhou.
        String region = "cn-hangzhou";

        // Obtain access credentials from environment variables. Before you run the sample code, you must configure the environment variables.
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();

        // Create an OSSClient instance.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        // To enable CNAME, set this parameter to true.
        clientBuilderConfiguration.setSupportCname(true);
        // Explicitly declare the use of the V4 signature algorithm.
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            // Specify the validity period of the presigned URL. Unit: milliseconds. In this example, the validity period is 1 hour. 
            Date expiration = new Date(new Date().getTime() + 3600 * 1000L);
            // Generate a presigned URL that allows HTTP GET requests. In this example, no additional request headers are specified. Other users can access the relevant content directly by using the browser. 
            String bucketName = "examplebucket";
            String objectName = "demo.png";
            URL url = ossClient.generatePresignedUrl(bucketName, objectName, expiration);
            System.out.println(url);
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            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("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

# -*- coding: utf-8 -*-
import oss2
from oss2.credentials import EnvironmentVariableCredentialsProvider

# 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. 
auth = oss2.ProviderAuthV4(EnvironmentVariableCredentialsProvider())

# Specify the ID of the region that maps to the endpoint. Example: cn-hangzhou. This parameter is required if you use the signature algorithm V4.
region = "cn-hangzhou"

# Specify the custom domain name. Example: static.example.com.
endpoint = 'http://static.example.com'

# Specify the name of your bucket.
bucket = oss2.Bucket(auth, endpoint, "yourBucketName", region=region, is_cname=True)


# Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt.
object_name = 'exampledir/exampleobject.txt'

# Generate a presigned URL that is used to download the object. In this example, the validity period of the URL is 600 seconds.
# By default, OSS identifies forward slashes (/) in the full path of an object as escape characters in the signing process. Therefore, the presigned URL cannot be directly used.
# Set the slash_safe parameter to True. This way, OSS does not identify the forward slashes (/) in the full path of the object as escape characters, and the presigned URL can be directly used.
url = bucket.sign_url('GET', object_name, 600, slash_safe=True, params=params)
print('Presigned URL:', url)

const OSS = require("ali-oss");

// Specify a function used to generate a presigned URL.
async function generateSignatureUrl(fileName) {
  // Obtain the presigned URL.
  const client = await new OSS({
      // Specify the custom domain name that you want to map to the bucket.
      endpoint: 'http://static.example.com', 
      // 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.
      accessKeyId: process.env.OSS_ACCESS_KEY_ID,
      accessKeySecret: process.env.OSS_ACCESS_KEY_SECRET,
      bucket: 'examplebucket',
      // 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 oss-cn-hangzhou.
      region: 'oss-cn-hangzhou',
      authorizationV4: true,
      cname: true
  });

  return await client.signatureUrlV4('GET', 3600, {
      headers: {} // Specify the request headers based on the actual request headers.
  }, fileName);
}
// Call the function and pass in the name of the object.
generateSignatureUrl('yourFileName').then(url => {
  console.log('Generated Signature URL:', url);
}).catch(err => {
  console.error('Error generating signature URL:', err);
});

<?php
if (is_file(__DIR__ . '/../autoload.php')) {
    require_once __DIR__ . '/../autoload.php';
}
if (is_file(__DIR__ . '/../vendor/autoload.php')) {
    require_once __DIR__ . '/../vendor/autoload.php';
}

use OSS\OssClient;
use OSS\Core\OssException;
use OSS\Http\RequestCore;
use OSS\Http\ResponseCore;
use OSS\Credentials\EnvironmentVariableCredentialsProvider;

// 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 = new EnvironmentVariableCredentialsProvider();
// 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 http://static.example.com.
$endpoint = "http://static.example.com";
// Specify the name of the bucket.
$bucket= "examplebucket";
// Specify the full path of the object. Do not include the bucket name in the full path.
$object = "exampleobject.txt";
// Set the validity period of the presigned URL to 600 seconds. Maximum value: 32400.
$timeout = 600;
try {
    $config = array(  
        "provider" => $provider,
        "endpoint" => $endpoint,
        'signatureVersion'=>OssClient::OSS_SIGNATURE_VERSION_V4,
        "cname"	=> true,
        "region"=> "cn-hangzhou"
    );
    $ossClient = new OssClient($config);
    // Generate a presigned URL.
    $signedUrl = $ossClient->signUrl($bucket, $object, $timeout, "GET");
    print_r($signedUrl);
} catch (OssException $e) {
    printf(__FUNCTION__ . ": FAILED\n");
    printf($e->getMessage() . "\n");
    return;
}

package main

import (
	"context"
	"flag"
	"log"
	"time"

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

// Specify the global variables.
var (
	region     string // Region in which the bucket is located.
	bucketName string // Name of the bucket.
	objectName string // Name of the object.
)

// Specify the init function used to initialize command line parameters.
func init() {
	flag.StringVar(&region, "region", "", "The region in which the bucket is located.")
	flag.StringVar(&bucketName, "bucket", "", "The name of the bucket.")
	flag.StringVar(&objectName, "object", "", "The name of the object.")
}

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

	// Check whether the name of the bucket is specified.
	if len(bucketName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, bucket name required")
	}

	// Check whether the region is specified.
	if len(region) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, region required")
	}

	// Check whether the object is specified.
	if len(objectName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, object name required")
	}

	// Load the default configurations and specify the credential provider and region.
	cfg := oss.LoadDefaultConfig().
		WithCredentialsProvider(credentials.NewEnvironmentVariableCredentialsProvider()).
		WithRegion(region).
		WithEndpoint("http://static.example.com").
		WithUseCName(true)

	// Create an OSS client.
	client := oss.NewClient(cfg)

	// Generate a presigned URL for the GetObject request.
	result, err := client.Presign(context.TODO(), &oss.GetObjectRequest{
		Bucket: oss.Ptr(bucketName),
		Key:    oss.Ptr(objectName),
		//RequestPayer: oss.Ptr("requester"), // Specify the identity of the requester.
	},
		oss.PresignExpires(10*time.Minute),
	)
	if err != nil {
		log.Fatalf("failed to get object presign %v", err)
	}

	log.Printf("request method:%v\n", result.Method)
	log.Printf("request expiration:%v\n", result.Expiration)
	log.Printf("request url:%v\n", result.URL)
	if len(result.SignedHeaders) > 0 {
		// If you specify request headers when you generate a presigned URL that allows HTTP GET requests, make sure that the request headers are included in the GET request initiated by using the presigned URL. This prevents request failures and signature errors.
		log.Printf("signed headers:\n")
		for k, v := range result.SignedHeaders {
			log.Printf("%v: %v\n", k, v)
		}
	}
}

Use ossutil

Use the custom domain name to generate a presigned URL for an object by running the presign command.

ossutil presign oss://examplebucket/exampleobject.txt --endpoint "http://static.example.com” --addressing-style "cname"

To enable the ossutil command to automatically use a custom domain name, instead of manually specifying it each time, add the custom domain name to the configuration file.

Java

import com.aliyun.oss.*;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.GeneratePresignedUrlRequest;

import java.net.URL;
import java.net.URLEncoder;
import java.util.Date;

public class Demo {
    public static void main(String[] args) throws Throwable {
        //  Specify a custom domain name. Example: https://static.example.com. 
        String endpoint = "http://static.example.com";
        // 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 name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Example: exampleobject.txt. Do not include the bucket name in the full path of the object. 
        String objectName = "exampleobject.txt";

        // Create an OSSClient instance. 
        String region = "cn-hangzhou";
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        // Note that if you use a custom domain name, you must set CNAME to true. 
        clientBuilderConfiguration.setSupportCname(true);

        // Explicitly declare the use of the V4 signature algorithm.
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        URL signedUrl = null;
        try {
            // Specify the validity period of the presigned URL. Unit: milliseconds. In this example, the validity period is 1 hour. 
            Date expiration = new Date(new Date().getTime() + 3600 * 1000L);

            // Specify the name of the object that you want to forcibly download. Example: homework.txt. 
            String filename = "homework.txt";

            // Generate a presigned URL. 
            GeneratePresignedUrlRequest request = new GeneratePresignedUrlRequest(bucketName, objectName, HttpMethod.GET);

            // Specify that the object is forcibly downloaded and specify the name of the downloaded object.
            request.getResponseHeaders().setContentDisposition("attachment;filename=" + URLEncoder.encode(filename,"UTF-8"));

            // Set the validity period of the request. 
            request.setExpiration(expiration);

            // Generate the presigned URL that allows HTTP GET requests. 
            signedUrl = ossClient.generatePresignedUrl(request);
            // Display the presigned URL. 
            System.out.println("signed url for putObject: " + signedUrl);
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            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("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        }
    }

}

Python

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="presign get object sample")

# Specify the --region parameter, which specifies the region in which the bucket is located. This command line 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 name of the bucket in which the object is stored. This parameter is required.
parser.add_argument('--bucket', help='The name of the bucket.', required=True)
# Specify the --endpoint parameter, which specifies the endpoint that other services can use to access OSS. This command line parameter is optional.
parser.add_argument('--endpoint', help='The domain names that other services can use to access OSS')
# Specify the --key parameter, which specifies the name of the object. This command line parameter is required.
parser.add_argument('--key', help='The name of the object.', required=True)

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

    # Load the authentication information required to access OSS from the environment variables.
    credentials_provider = oss.credentials.EnvironmentVariableCredentialsProvider()

    # Use the default configuration to create a configuration object and specify the credential provider.
    cfg = oss.config.load_default()
    cfg.credentials_provider = credentials_provider

    # Set the region attribute of the configuration object based on the command line parameters provided by the user.
    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

    # Use the preceding configuration to initialize the OSSClient instance and allow the instance to interact with OSS.
    client = oss.Client(cfg)

    # Initiate a request to generate a presigned URL.
    pre_result = client.presign(
        oss.GetObjectRequest(
            bucket=args.bucket,  # Specify the bucket name.
            key=args.key,        # Specify the object key.
            response_content_disposition="attachment;filename=test.txt",
        )
    )

    # Display the HTTP method, expiration time, and presigned URL.
    print(f'method: {pre_result.method},'
          f' expiration: {pre_result.expiration.strftime("%Y-%m-%dT%H:%M:%S.000Z")},'
          f' url: {pre_result.url}'
    )

    # Display the signed headers.
    for key, value in pre_result.signed_headers.items():
        print(f'signed headers key: {key}, signed headers value: {value}')

# Call the main function to start the processing logic when the script is directly run.
if __name__ == "__main__":
    main()  # Script entry point, program flow starts here

Go

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"
)

// Specify the global variables.
var (
	region     string // The region in which the bucket is located.
	bucketName string // The name of the bucket.
	objectName string // The name of the object.
)

// Specify the init function used to initialize command line parameters.
func init() {
	flag.StringVar(&region, "region", "", "The region in which the bucket is located.")
	flag.StringVar(&bucketName, "bucket", "", "The name of the bucket.")
	flag.StringVar(&objectName, "object", "", "The name of the object.")
}

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

	// Check whether the bucket name is empty.
	if len(bucketName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, bucket name required")
	}

	// Check whether the region is empty.
	if len(region) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, region required")
	}

	// Check whether the object name is empty.
	if len(objectName) == 0 {
		flag.PrintDefaults()
		log.Fatalf("invalid parameters, object name required")
	}

	// Load the default configurations and specify the credential provider and region.
	cfg := oss.LoadDefaultConfig().
		WithCredentialsProvider(credentials.NewEnvironmentVariableCredentialsProvider()).
		WithRegion(region)

	// Create an OSS client.
	client := oss.NewClient(cfg)

	// Generate a signed URL for the GetObject request.
	result, err := client.Presign(context.TODO(), &oss.GetObjectRequest{
		Bucket:                     oss.Ptr(bucketName),
		Key:                        oss.Ptr(objectName),
		ResponseContentDisposition: oss.Ptr("attachment;filename=test.txt"),
	},
	)
	if err != nil {
		log.Fatalf("failed to get object presign %v", err)
	}

	log.Printf("request method:%v\n", result.Method)
	log.Printf("request expiration:%v\n", result.Expiration)
	log.Printf("request url:%v\n", result.URL)
	if len(result.SignedHeaders) > 0 {
		//If you specify request headers when you generate a signed URL that allows HTTP GET requests, make sure that the request headers are included in the GET request initiated by using the signed URL.
		log.Printf("signed headers:\n")
		for k, v := range result.SignedHeaders {
			log.Printf("%v: %v\n", k, v)
		}
	}
}

Use the OSS console

1. Select the target objects and click Export URL List below.

2. In the Export URL List panel, configure the following parameters:

   Parameter	Description
   Use HTTPS	By default, the URLs of objects are generated using HTTPS. If you want to generate URLs of objects by using HTTP, turn off Use HTTPS.
   Validity Period	If the ACL of the objects that you want to share is private, you must set a validity period for the URLs of the objects. Valid values: 60 to 32400. Unit: seconds
   Custom Domain Name	If you want to ensure that an image or webpage object is previewed instead of being downloaded when it is accessed by using a URL, use the custom domain name that is mapped to the bucket. You can configure this parameter only after you map a custom domain name to the bucket.
   Accelerate Endpoint	If third parties located far from your data centers need to access the objects, we recommend that you use the acceleration endpoint of the bucket to generate the URLs of the objects. You can configure this parameter only after you enable transfer acceleration for the bucket.

3. Click OK, and then save the URL list file to your computer.

Use ossutil

• For objects in the "folder" directory in the examplebucket bucket, generate presigned URLs that have a validity period of 15 minutes.

  ossutil presign oss://examplebucket/folder/ -r

• For TXT objects in the "folder" directory of the examplebucket bucket, generate presigned URLs that have the default validity period of 15 minutes.

  ossutil presign oss://examplebucket/folder/ -r --include "*.txt"

• For all objects in the examplebucket bucket, generate presigned URLs that have the default validity period of 15 minutes.

  ossutil presign oss://examplebucket/ -r

For more information about how to use ossutil to generate presigned URLs, see presign.