Create a GET-signed URL for an object using Cloud Storage libraries (V4)

Generate a V4-signed URL to download an object.

Documentation pages that include this code sample

To view the code sample used in context, see the following documentation:

Code sample

C#

For more information, see the Cloud Storage C# API reference documentation.


using Google.Cloud.Storage.V1;
using System;
using System.Net.Http;

public class GenerateV4SignedReadUrlSample
{
    public string GenerateV4SignedReadUrl(
        string bucketName = "your-unique-bucket-name",
        string objectName = "your-object-name",
        string credentialFilePath = "my-local-path/my-credential-file-name")
    {
        UrlSigner urlSigner = UrlSigner.FromServiceAccountPath(credentialFilePath);
        // V4 is the default signing version.
        string url = urlSigner.Sign(bucketName, objectName, TimeSpan.FromHours(1), HttpMethod.Get);
        Console.WriteLine("Generated GET signed URL:");
        Console.WriteLine(url);
        Console.WriteLine("You can use this URL with any user agent, for example:");
        Console.WriteLine($"curl '{url}'");
        return url;
    }
}

C++

For more information, see the Cloud Storage C++ API reference documentation.

namespace gcs = ::google::cloud::storage;
using ::google::cloud::StatusOr;
[](gcs::Client client, std::string const& bucket_name,
   std::string const& object_name, std::string const& signing_account) {
  StatusOr<std::string> signed_url = client.CreateV4SignedUrl(
      "GET", std::move(bucket_name), std::move(object_name),
      gcs::SignedUrlDuration(std::chrono::minutes(15)),
      gcs::SigningAccount(signing_account));

  if (!signed_url) throw std::runtime_error(signed_url.status().message());
  std::cout << "The signed url is: " << *signed_url << "\n\n"
            << "You can use this URL with any user agent, for example:\n"
            << "curl '" << *signed_url << "'\n";
}

Go

For more information, see the Cloud Storage Go API reference documentation.

jsonKey, err := ioutil.ReadFile(serviceAccount)
if err != nil {
	return "", fmt.Errorf("cannot read the JSON key file, err: %v", err)
}

conf, err := google.JWTConfigFromJSON(jsonKey)
if err != nil {
	return "", fmt.Errorf("google.JWTConfigFromJSON: %v", err)
}

opts := &storage.SignedURLOptions{
	Scheme:         storage.SigningSchemeV4,
	Method:         "GET",
	GoogleAccessID: conf.Email,
	PrivateKey:     conf.PrivateKey,
	Expires:        time.Now().Add(15 * time.Minute),
}

u, err := storage.SignedURL(bucketName, objectName, opts)
if err != nil {
	return "", fmt.Errorf("Unable to generate a signed URL: %v", err)
}

fmt.Fprintln(w, "Generated GET signed URL:")
fmt.Fprintf(w, "%q\n", u)
fmt.Fprintln(w, "You can use this URL with any user agent, for example:")
fmt.Fprintf(w, "curl %q\n", u)

Java

For more information, see the Cloud Storage Java API reference documentation.

import com.google.cloud.storage.BlobId;
import com.google.cloud.storage.BlobInfo;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageException;
import com.google.cloud.storage.StorageOptions;
import java.net.URL;
import java.util.concurrent.TimeUnit;

public class GenerateV4GetObjectSignedUrl {
  /**
   * Signing a URL requires Credentials which implement ServiceAccountSigner. These can be set
   * explicitly using the Storage.SignUrlOption.signWith(ServiceAccountSigner) option. If you don't,
   * you could also pass a service account signer to StorageOptions, i.e.
   * StorageOptions().newBuilder().setCredentials(ServiceAccountSignerCredentials). In this example,
   * neither of these options are used, which means the following code only works when the
   * credentials are defined via the environment variable GOOGLE_APPLICATION_CREDENTIALS, and those
   * credentials are authorized to sign a URL. See the documentation for Storage.signUrl for more
   * details.
   */
  public static void generateV4GetObjectSignedUrl(
      String projectId, String bucketName, String objectName) throws StorageException {
    // String projectId = "my-project-id";
    // String bucketName = "my-bucket";
    // String objectName = "my-object";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();

    // Define resource
    BlobInfo blobInfo = BlobInfo.newBuilder(BlobId.of(bucketName, objectName)).build();

    URL url =
        storage.signUrl(blobInfo, 15, TimeUnit.MINUTES, Storage.SignUrlOption.withV4Signature());

    System.out.println("Generated GET signed URL:");
    System.out.println(url);
    System.out.println("You can use this URL with any user agent, for example:");
    System.out.println("curl '" + url + "'");
  }
}

Node.js

For more information, see the Cloud Storage Node.js API reference documentation.

/**
 * TODO(developer): Uncomment the following lines before running the sample.
 * Note: when creating a signed URL, unless running in a GCP environment,
 * a service account must be used for authorization.
 */
// The ID of your GCS bucket
// const bucketName = 'your-unique-bucket-name';

// The full path of your file inside the GCS bucket, e.g. 'yourFile.jpg' or 'folder1/folder2/yourFile.jpg'
// const fileName = 'your-file-name';

// Imports the Google Cloud client library
const {Storage} = require('@google-cloud/storage');

// Creates a client
const storage = new Storage();

async function generateV4ReadSignedUrl() {
  // These options will allow temporary read access to the file
  const options = {
    version: 'v4',
    action: 'read',
    expires: Date.now() + 15 * 60 * 1000, // 15 minutes
  };

  // Get a v4 signed URL for reading the file
  const [url] = await storage
    .bucket(bucketName)
    .file(fileName)
    .getSignedUrl(options);

  console.log('Generated GET signed URL:');
  console.log(url);
  console.log('You can use this URL with any user agent, for example:');
  console.log(`curl '${url}'`);
}

generateV4ReadSignedUrl().catch(console.error);

PHP

For more information, see the Cloud Storage PHP API reference documentation.

use Google\Cloud\Storage\StorageClient;

/**
 * Generate a v4 signed URL for downloading an object.
 *
 * @param string $bucketName The name of your Cloud Storage bucket.
 * @param string $objectName The name of your Cloud Storage object.
 */
function get_object_v4_signed_url($bucketName, $objectName)
{
    // $bucketName = 'my-bucket';
    // $objectName = 'my-object';

    $storage = new StorageClient();
    $bucket = $storage->bucket($bucketName);
    $object = $bucket->object($objectName);
    $url = $object->signedUrl(
        # This URL is valid for 15 minutes
        new \DateTime('15 min'),
        [
            'version' => 'v4',
        ]
    );

    print('Generated GET signed URL:' . PHP_EOL);
    print($url . PHP_EOL);
    print('You can use this URL with any user agent, for example:' . PHP_EOL);
    print('curl ' . $url . PHP_EOL);
}

Python

For more information, see the Cloud Storage Python API reference documentation.

import datetime

from google.cloud import storage


def generate_download_signed_url_v4(bucket_name, blob_name):
    """Generates a v4 signed URL for downloading a blob.

    Note that this method requires a service account key file. You can not use
    this if you are using Application Default Credentials from Google Compute
    Engine or from the Google Cloud SDK.
    """
    # bucket_name = 'your-bucket-name'
    # blob_name = 'your-object-name'

    storage_client = storage.Client()
    bucket = storage_client.bucket(bucket_name)
    blob = bucket.blob(blob_name)

    url = blob.generate_signed_url(
        version="v4",
        # This URL is valid for 15 minutes
        expiration=datetime.timedelta(minutes=15),
        # Allow GET requests using this URL.
        method="GET",
    )

    print("Generated GET signed URL:")
    print(url)
    print("You can use this URL with any user agent, for example:")
    print("curl '{}'".format(url))
    return url

Ruby

For more information, see the Cloud Storage Ruby API reference documentation.

def generate_signed_url_v4 bucket_name:, file_name:
  # The ID of your GCS bucket
  # bucket_name = "your-unique-bucket-name"

  # The ID of your GCS object
  # file_name = "your-file-name"

  require "google/cloud/storage"

  storage = Google::Cloud::Storage.new
  storage_expiry_time = 5 * 60 # 5 minutes

  url = storage.signed_url bucket_name, file_name, method: "GET",
                           expires: storage_expiry_time, version: :v4

  puts "Generated GET signed url:"
  puts url
  puts "You can use this URL with any user agent, for example:"
  puts "curl #{url}"
end

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