Object Storage Service:Using presigned URLs to download or preview files

Java

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 {
        // Endpoint of the region where the bucket is located. Example: China (Hangzhou).
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Credentials loaded from environment variables.
        EnvironmentVariableCredentialsProvider credentialsProvider =
            CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        String bucketName = "examplebucket";
        // Full object path, without the bucket name. Example: exampleobject.txt.
        String objectName = "exampleobject.txt";
        String region = "cn-hangzhou";

        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            // Validity period: 1 hour (in milliseconds).
            Date expiration = new Date(new Date().getTime() + 3600 * 1000L);
            URL url = ossClient.generatePresignedUrl(bucketName, objectName, expiration);
            System.out.println(url);
        } catch (OSSException oe) {
            System.out.println("Error Code: " + oe.getErrorCode());
            System.out.println("Request ID: " + oe.getRequestId());
        } catch (ClientException ce) {
            System.out.println("Error: " + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}

For more information, see Download files using presigned URLs in Java.

Python

import argparse
import alibabacloud_oss_v2 as oss

parser = argparse.ArgumentParser(description="presign get object sample")
parser.add_argument('--region', required=True)
parser.add_argument('--bucket', required=True)
parser.add_argument('--endpoint')
parser.add_argument('--key', required=True)

def main():
    args = parser.parse_args()
    credentials_provider = oss.credentials.EnvironmentVariableCredentialsProvider()
    cfg = oss.config.load_default()
    cfg.credentials_provider = credentials_provider
    cfg.region = args.region
    if args.endpoint is not None:
        cfg.endpoint = args.endpoint

    client = oss.Client(cfg)
    pre_result = client.presign(
        oss.GetObjectRequest(
            bucket=args.bucket,
            key=args.key,
        )
    )
    print(f'method: {pre_result.method},'
          f' expiration: {pre_result.expiration.strftime("%Y-%m-%dT%H:%M:%S.000Z")},'
          f' url: {pre_result.url}')
    for key, value in pre_result.signed_headers.items():
        print(f'signed headers key: {key}, signed headers value: {value}')

if __name__ == "__main__":
    main()

For more information, see Download files using presigned URLs in Python.

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"
)

var (
    region     string
    bucketName string
    objectName string
)

func init() {
    flag.StringVar(&region, "region", "", "The region where the bucket is located.")
    flag.StringVar(&bucketName, "bucket", "", "The bucket name.")
    flag.StringVar(&objectName, "object", "", "The object name.")
}

func main() {
    flag.Parse()
    if len(bucketName) == 0 || len(region) == 0 || len(objectName) == 0 {
        flag.PrintDefaults()
        log.Fatalf("invalid parameters: region, bucket, and object are required")
    }

    cfg := oss.LoadDefaultConfig().
        WithCredentialsProvider(credentials.NewEnvironmentVariableCredentialsProvider()).
        WithRegion(region)

    client := oss.NewClient(cfg)

    result, err := client.Presign(context.TODO(), &oss.GetObjectRequest{
        Bucket: oss.Ptr(bucketName),
        Key:    oss.Ptr(objectName),
    },
        oss.PresignExpires(10*time.Minute),
    )
    if err != nil {
        log.Fatalf("failed to presign: %v", err)
    }

    log.Printf("method: %v", result.Method)
    log.Printf("expiration: %v", result.Expiration)
    log.Printf("url: %v", result.URL)
}

For more information, see Download files using presigned URLs in Go.

Node.js

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

async function generateSignatureUrl(fileName) {
    const client = await new OSS({
        accessKeyId: process.env.OSS_ACCESS_KEY_ID,
        accessKeySecret: process.env.OSS_ACCESS_KEY_SECRET,
        bucket: 'examplebucket',
        region: 'oss-cn-hangzhou',
        // Use HTTPS to prevent browsers from blocking the download link.
        secure: true,
        authorizationV4: true
    });

    return await client.signatureUrlV4('GET', 3600, {
        headers: {}
    }, fileName);
}

generateSignatureUrl('yourFileName').then(url => {
    console.log('Generated URL:', url);
}).catch(err => {
    console.error('Error:', err);
});

For more information, see Download files using presigned URLs in Node.js.

PHP

<?php

require_once __DIR__ . '/../vendor/autoload.php';

use AlibabaCloud\Oss\V2 as Oss;

$optsdesc = [
    "region"   => ['help' => 'The region where the bucket is located.', 'required' => true],
    "endpoint" => ['help' => 'The OSS endpoint.', 'required' => false],
    "bucket"   => ['help' => 'The bucket name.', 'required' => true],
    "key"      => ['help' => 'The object name.', 'required' => true],
];
$longopts = array_map(fn($key) => "$key:", array_keys($optsdesc));
$options = getopt("", $longopts);

foreach ($optsdesc as $key => $value) {
    if ($value['required'] && empty($options[$key])) {
        echo "Error: --$key is required. " . $value['help'] . PHP_EOL;
        exit(1);
    }
}

$credentialsProvider = new Oss\Credentials\EnvironmentVariableCredentialsProvider();
$cfg = Oss\Config::loadDefault();
$cfg->setCredentialsProvider($credentialsProvider);
$cfg->setRegion($options["region"]);
if (isset($options["endpoint"])) {
    $cfg->setEndpoint($options["endpoint"]);
}

$client = new Oss\Client($cfg);
$request = new Oss\Models\GetObjectRequest(bucket: $options["bucket"], key: $options["key"]);
$result = $client->presign($request);

print('url: ' . $result->url . PHP_EOL);

For more information, see Download files using presigned URLs in PHP.

Java

// Specify a custom domain name as the endpoint.
String endpoint = "https://static.example.com"; // Replace with your custom domain name.
String region = "cn-hangzhou";
String bucketName = "examplebucket";
String objectName = "exampleobject.txt";

EnvironmentVariableCredentialsProvider credentialsProvider =
    CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();

ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
clientBuilderConfiguration.setSupportCname(true);   // Enable CNAME
clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);

OSS ossClient = OSSClientBuilder.create()
        .endpoint(endpoint)
        .credentialsProvider(credentialsProvider)
        .clientConfiguration(clientBuilderConfiguration)
        .region(region)
        .build();

try {
    Date expiration = new Date(new Date().getTime() + 3600 * 1000L);
    GeneratePresignedUrlRequest request =
        new GeneratePresignedUrlRequest(bucketName, objectName, HttpMethod.GET);
    request.setExpiration(expiration);
    URL signedUrl = ossClient.generatePresignedUrl(request);
    System.out.println("Preview URL: " + signedUrl);
} finally {
    if (ossClient != null) ossClient.shutdown();
}

Python

cfg = oss.config.load_default()
cfg.credentials_provider = oss.credentials.EnvironmentVariableCredentialsProvider()
cfg.region = args.region
cfg.endpoint = "http://static.example.com"  # Replace with your custom domain name.
cfg.use_cname = True                         # Enable CNAME

client = oss.Client(cfg)
pre_result = client.presign(
    oss.GetObjectRequest(bucket=args.bucket, key=args.key)
)
print(f'url: {pre_result.url}')

Go

cfg := oss.LoadDefaultConfig().
    WithCredentialsProvider(credentials.NewEnvironmentVariableCredentialsProvider()).
    WithRegion(region).
    WithEndpoint("http://static.example.com"). // Replace with your custom domain name.
    WithUseCName(true)                          // Enable CNAME

client := oss.NewClient(cfg)
result, err := client.Presign(context.TODO(), &oss.GetObjectRequest{
    Bucket: oss.Ptr(bucketName),
    Key:    oss.Ptr(objectName),
},
    oss.PresignExpires(10*time.Minute),
)

Node.js

const client = await new OSS({
    endpoint: 'http://static.example.com',  // Replace with your custom domain name.
    accessKeyId: process.env.OSS_ACCESS_KEY_ID,
    accessKeySecret: process.env.OSS_ACCESS_KEY_SECRET,
    bucket: 'examplebucket',
    region: 'oss-cn-hangzhou',
    authorizationV4: true,
    cname: true  // Enable CNAME
});

PHP

$cfg->setEndpoint("http://static.example.com"); // Replace with your custom domain name.
$cfg->setUseCname(true);                         // Enable CNAME

Java

String versionId = "CAEQARiBgID8rumR2hYiIGUyOTAyZGY2MzU5MjQ5ZjlhYzQzZjNlYTAyZDE3****";
Map<String, String> queryParam = new HashMap<>();
queryParam.put("versionId", versionId);
request.setQueryParameter(queryParam);

Python

pre_result = client.presign(
    oss.GetObjectRequest(
        bucket=bucket_name,
        key=object_name,
        version_id='CAEQARiBgID8rumR2hYiIGUyOTAyZGY2MzU5MjQ5ZjlhYzQzZjNlYTAyZDE3****',
    )
)

Go

result, err := client.Presign(context.TODO(), &oss.GetObjectRequest{
    Bucket:    oss.Ptr(bucketName),
    Key:       oss.Ptr(objectName),
    VersionId: oss.Ptr("CAEQARiBgID8rumR2hYiIGUyOTAyZGY2MzU5MjQ5ZjlhYzQzZjNlYTAyZDE7****"),
},
    oss.PresignExpires(10*time.Minute),
)

Node.js

const signedUrl = await client.signatureUrlV4('GET', 3600, {
    queries: {
        "versionId": 'CAEQARiBgID8rumR2hYiIGUyOTAyZGY2MzU5MjQ5ZjlhYzQzZjNlYTAyZDE7****'
    }
}, objectName);

PHP

$versionId = "yourVersionId";
$request = new Oss\Models\GetObjectRequest(bucket: $bucket, key: $key, versionId: $versionId);

Java

// Validity period: 1 hour
Date expiration = new Date(new Date().getTime() + 3600 * 1000L);
URL url = ossClient.generatePresignedUrl(bucketName, objectName, expiration);

Python

pre_result = client.presign(
    oss.GetObjectRequest(bucket=args.bucket, key=args.key)
)

Go

result, err := client.Presign(context.TODO(), &oss.GetObjectRequest{
    Bucket: oss.Ptr(bucketName),
    Key:    oss.Ptr(objectName),
},
    oss.PresignExpires(10*time.Minute), // Set validity period
)

Node.js

// The second parameter sets the validity period in seconds. Example: 3600 = 1 hour.
return await client.signatureUrlV4('GET', 3600, {headers: {}}, fileName);

PHP

See Download objects using presigned URLs in PHP.