V4 signing process with Cloud Storage tools

V4 signing is a process you can use to generate signatures for authentication in Cloud Storage XML API requests. This page describes how to use the Google Cloud CLI and Cloud Storage client libraries to create signed URLs, using service account credentials. Signed URLs give time-limited read or write access to a specific Cloud Storage resource. If you want to make your own program for creating signed URLs, read V4 signing with your own program instead.

Note: HMAC credentials are not supported when using Cloud Storage tools to generate signed URLs.

Before you begin

To create signed URLs, complete the tasks in the following sections.

Enable the Service Account Credentials API

Note: This step is only needed if you plan on using a client library that calls the signBlob method, which is used to authenticate instead of a private key file.

Enable the Service Account Credentials API.

Enable the API

Get required roles

In order to get the required permissions for creating a signed URL to download and upload objects, ask your administrator to grant the following roles:

• Storage Object User (roles/storage.objectUser): this role is required for downloading, uploading, and overwriting objects. This role should be granted to the service account whose key will be used to sign the URL.

  • If you only want to download objects, ask your administrator to grant the service account the Storage Object Viewer (roles/storage.objectViewer) role instead of the Storage Object User role.

  • If you only want to upload objects (without overwriting), ask your administrator to grant the service account the Storage Object Creator (roles/storage.objectCreator) role instead of the Storage Object User role.

• Service Account Token Creator (roles/iam.serviceAccountTokenCreator): this role is required for generating short-lived credentials for a service account when a private key file is not provided locally. This role should be granted to the principal that will create the signed URL.

  • If you use user credentials for authentication, your user identity must have this role and you must modify commands to impersonate the service account that is used to sign the URL.

  • If you use a service account attached to a compute instance for authentication, the service account must have this role to impersonate itself and you must modify commands to impersonate the service account used to sign the URL.

  • If you use a private key file for authentication, this role is not necessary.

These predefined roles contain the permissions required for a service account to download and upload objects using signed URLs. To see the exact permissions that are required, expand the Required permissions section:

Required permissions

• storage.objects.get
• storage.objects.create (not required if you only want to download objects)
• storage.objects.delete (not required if you don't need to overwrite objects when uploading)
• iam.serviceAccounts.signBlob (not required if you plan on providing a service account key locally to create the signature, which doesn't require calling the signBlob method)

You might also be able to get these permissions with custom roles or other predefined roles. To see which roles are associated with which permissions, refer to IAM roles for Cloud Storage.

For instructions on granting roles on projects, see Manage access to projects.

Create a signed URL to download an object

To create a signed URL that can get an object from a bucket, complete the following steps:

Command line

Note: Creating signed URLs with gcloud storage requires the pyopenssl library. If you encounter an error indicating that this library is missing, use pip install pyopenssl or easy_install pyopenssl to get the library. You must also set the following environment variable: CLOUDSDK_PYTHON_SITEPACKAGES=1.

1. Generate a new private key, or use an existing private key for a service account. The key should be in JSON format.

   For more information on private keys and service accounts, see Service Accounts.

2. Use the gcloud storage sign-url command. For example, the following command creates a signed URL that allows users to download an object for 10 minutes:

   gcloud storage sign-url gs://BUCKET_NAME/OBJECT_NAME --private-key-file=KEY_FILE --duration=10m

   Where:

   • BUCKET_NAME is the name of the bucket where the object is located. For example, example-bucket.

   • OBJECT_NAME is the name of the object to download. For example, cat.jpeg.

   • KEY_FILE is the path to the file containing your service account's private key. For example, Desktop/private-key.json.

   If successful, your response should look like:

   ---
   expiration: '2023-07-14 23:19:35'
   http_verb: GET
   resource: gs://example-bucket/cat.jpeg
   signed_url: https://storage.googleapis.com/example-bucket/cat.jpeg?
   x-goog-signature=11ae9c61ca84dd0bec319f7d52a38029e5873caa2eeced0568
   ef96076258cfc1a925a9683cc907d210036b61af9e06a13bf4a15b15fab3916669b
   e2f4c9f66ea6be822bec5858af519a6da705415b5768721197be213103fa09b8a18
   8a143be77a24351517ff208a2c62cfebb78040daf1f953907080bd98f9462739d11
   1355b1d9bcf54705b862f37392c031fde0d52add1a4d3bbb98a22e8b7023f6a1623
   2e0a2dd56e524d410624d28663e557fafaf4ba0a04290a1066f894713857b429258
   d14f056066c7622baf114c124e645688e19b4df3c4a7925f580693c93fa9c1dae7f
   dff0edff7259c72f3f0eadc5a9f9f556c83c9c8dc02ee3af8d20ab634bad&x-goog
   -algorithm=GOOG4-RSA-SHA256&x-goog-credential=example%40example-pro
   ject.iam.gserviceaccount.com%2F20230714%2Fus%2Fstorage%2Fgoog4_requ
   est&x-goog-date=20230714T221935Z&x-goog-expires=600&x-goog-signedhe
   aders=host

   This URL can be used by any person to access the associated resource (in this case cat.jpeg) for the designated length of time (in this case, 10 minutes).

Client libraries

C++

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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", bucket_name, object_name,
      gcs::SignedUrlDuration(std::chrono::minutes(15)),
      gcs::SigningAccount(signing_account));

  if (!signed_url) throw std::move(signed_url).status();
  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";
}

C#

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

using Google.Apis.Auth.OAuth2;
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")
    {
        UrlSigner urlSigner = UrlSigner.FromCredential(GoogleCredential.GetApplicationDefault());
        // 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;
    }
}

Go

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import (
	"context"
	"fmt"
	"io"
	"time"

	"cloud.google.com/go/storage"
)

// generateV4GetObjectSignedURL generates object signed URL with GET method.
func generateV4GetObjectSignedURL(w io.Writer, bucket, object string) (string, error) {
	// bucket := "bucket-name"
	// object := "object-name"

	ctx := context.Background()
	client, err := storage.NewClient(ctx)
	if err != nil {
		return "", fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close()

	// Signing a URL requires credentials authorized to sign a URL. You can pass
	// these in through SignedURLOptions with one of the following options:
	//    a. a Google service account private key, obtainable from the Google Developers Console
	//    b. a Google Access ID with iam.serviceAccounts.signBlob permissions
	//    c. a SignBytes function implementing custom signing.
	// In this example, none of these options are used, which means the SignedURL
	// function attempts to use the same authentication that was used to instantiate
	// the Storage client. This authentication must include a private key or have
	// iam.serviceAccounts.signBlob permissions.
	opts := &storage.SignedURLOptions{
		Scheme:  storage.SigningSchemeV4,
		Method:  "GET",
		Expires: time.Now().Add(15 * time.Minute),
	}

	u, err := client.Bucket(bucket).SignedURL(object, opts)
	if err != nil {
		return "", fmt.Errorf("Bucket(%q).SignedURL: %w", bucket, 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)
	return u, nil
}

Java

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

/**
 * 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.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

use Google\Cloud\Storage\StorageClient;

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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(f"curl '{url}'")
    return url

Ruby

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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

Create a signed URL to upload an object

To create a signed URL that can upload an object to a bucket, complete the following steps:

Command line

Note: Creating signed URLs with gcloud storage requires the pyopenssl library. If you encounter an error indicating that this library is missing, use pip install pyopenssl or easy_install pyopenssl to get the library. You must also set the following environment variable: CLOUDSDK_PYTHON_SITEPACKAGES=1.

1. Generate a new private key, or use an existing private key for a service account. The key can be in either JSON or PKCS12 format.

   For more information on private keys and service accounts, see Service Accounts.

2. Use the gcloud storage sign-url command. For example, the following command creates a signed URL that allows users to upload a file for one hour:

   gcloud storage sign-url gs://BUCKET_NAME/OBJECT_NAME --private-key-file=KEY_FILE --http-verb=PUT --duration=1h --headers=Content-Type=CONTENT_TYPE

   • BUCKET_NAME is the name of the bucket where the object is being uploaded. For example, example-bucket.

   • OBJECT_NAME is the name to assign to the uploaded object. For example, cat.png.

   • KEY_FILE is the path to the file containing your service account's private key. For example, Desktop/private-key.json.

   • CONTENT_TYPE is the uploaded object's content type. For example, image/png.

   If successful, your response should look like:

   ---
   expiration: '2023-07-14 23:35:47'
   http_verb: PUT
   resource: gs://example-bucket/cat.png
   signed_url: https://storage.googleapis.com/example-bucket/cat.png?
   x-goog-signature=2f670a686102963e0574f3c1a3b4d29ee4aa406c1528d42d2
   30195d17fef73834b254314de7d7990afd48538a84b66f20010e7ecd90a900490e
   6119b7e56a912f71c8d64285c40e86f31b8fec51cf8c7a61ded81de3cedac9c1ca
   b92474b7371740fdac20b2d8d092b15396f79443bbde954a4174ed11aef6c2cf5f
   a4d72a84ff60fd6003ed0a505b0e40b6207ddbaec2a15778f715c3ec7537a1b14f
   b6661b2abaa5736f1670a412ca7e2555c830591f0595c01ff95af7f2206abe2e27
   41948c16d4bd4c7cbb25f41277ece59236c06e00ca6c63ae2eb3efc22c216bb24c
   e1b8b3801d07fd3a7ed3f2df3db6e59c6fc3cc76a002335dd936efd0237cf584e3
   6&x-goog-algorithm=GOOG4-RSA-SHA256&x-goog-credential=example%40ex
   ample-project.iam.gserviceaccount.com%2F20230714%2Fus%2Fstorage%2F
   goog4_request&x-goog-date=20230714T223547Z&x-goog-expires=3600&x-g
   oog-signedheaders=Content-Type%3Bhost

   This URL can be used by any person to upload a resource (in this case cat.png) to the specified Cloud Storage bucket for the designated length of time (in this case, 1 hour).

Client libraries

C++

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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(
      "PUT", bucket_name, object_name,
      gcs::SignedUrlDuration(std::chrono::minutes(15)),
      gcs::AddExtensionHeader("content-type", "application/octet-stream"),
      gcs::SigningAccount(signing_account));

  if (!signed_url) throw std::move(signed_url).status();
  std::cout << "The signed url is: " << *signed_url << "\n\n"
            << "You can use this URL with any user agent, for example:\n"
            << "curl -X PUT -H 'Content-Type: application/octet-stream'"
            << " --upload-file my-file '" << *signed_url << "'\n";
}

C#

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

using Google.Apis.Auth.OAuth2;
using Google.Cloud.Storage.V1;
using System;
using System.Collections.Generic;
using System.Net.Http;

public class GenerateV4UploadSignedUrlSample
{
    public string GenerateV4UploadSignedUrl(
        string bucketName = "your-unique-bucket-name",
        string objectName = "your-object-name")
    {
        UrlSigner urlSigner = UrlSigner.FromCredential(GoogleCredential.GetApplicationDefault());

        var contentHeaders = new Dictionary<string, IEnumerable<string>>
        {
            { "Content-Type", new[] { "text/plain" } }
        };

        // V4 is the default signing version.
        UrlSigner.Options options = UrlSigner.Options.FromDuration(TimeSpan.FromHours(1));

        UrlSigner.RequestTemplate template = UrlSigner.RequestTemplate
            .FromBucket(bucketName)
            .WithObjectName(objectName)
            .WithHttpMethod(HttpMethod.Put)
            .WithContentHeaders(contentHeaders);

        string url = urlSigner.Sign(template, options);
        Console.WriteLine("Generated PUT signed URL:");
        Console.WriteLine(url);
        Console.WriteLine("You can use this URL with any user agent, for example:");
        Console.WriteLine($"curl -X PUT -H 'Content-Type: text/plain' --upload-file my-file '{url}'");
        return url;
    }
}

Go

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import (
	"context"
	"fmt"
	"io"
	"time"

	"cloud.google.com/go/storage"
)

// generateV4GetObjectSignedURL generates object signed URL with PUT method.
func generateV4PutObjectSignedURL(w io.Writer, bucket, object string) (string, error) {
	// bucket := "bucket-name"
	// object := "object-name"

	ctx := context.Background()
	client, err := storage.NewClient(ctx)
	if err != nil {
		return "", fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close()

	// Signing a URL requires credentials authorized to sign a URL. You can pass
	// these in through SignedURLOptions with one of the following options:
	//    a. a Google service account private key, obtainable from the Google Developers Console
	//    b. a Google Access ID with iam.serviceAccounts.signBlob permissions
	//    c. a SignBytes function implementing custom signing.
	// In this example, none of these options are used, which means the SignedURL
	// function attempts to use the same authentication that was used to instantiate
	// the Storage client. This authentication must include a private key or have
	// iam.serviceAccounts.signBlob permissions.
	opts := &storage.SignedURLOptions{
		Scheme: storage.SigningSchemeV4,
		Method: "PUT",
		Headers: []string{
			"Content-Type:application/octet-stream",
		},
		Expires: time.Now().Add(15 * time.Minute),
	}

	u, err := client.Bucket(bucket).SignedURL(object, opts)
	if err != nil {
		return "", fmt.Errorf("Bucket(%q).SignedURL: %w", bucket, err)
	}

	fmt.Fprintln(w, "Generated PUT 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 -X PUT -H 'Content-Type: application/octet-stream' --upload-file my-file %q\n", u)
	return u, nil
}

Java

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import com.google.cloud.storage.BlobId;
import com.google.cloud.storage.BlobInfo;
import com.google.cloud.storage.HttpMethod;
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.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;

public class GenerateV4PutObjectSignedUrl {
  /**
   * 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 generateV4PutObjectSignedUrl(
      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();

    // Generate Signed URL
    Map<String, String> extensionHeaders = new HashMap<>();
    extensionHeaders.put("Content-Type", "application/octet-stream");

    URL url =
        storage.signUrl(
            blobInfo,
            15,
            TimeUnit.MINUTES,
            Storage.SignUrlOption.httpMethod(HttpMethod.PUT),
            Storage.SignUrlOption.withExtHeaders(extensionHeaders),
            Storage.SignUrlOption.withV4Signature());

    System.out.println("Generated PUT signed URL:");
    System.out.println(url);
    System.out.println("You can use this URL with any user agent, for example:");
    System.out.println(
        "curl -X PUT -H 'Content-Type: application/octet-stream' --upload-file my-file '"
            + url
            + "'");
  }
}

Node.js

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// 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 generateV4UploadSignedUrl() {
  // These options will allow temporary uploading of the file with outgoing
  // Content-Type: application/octet-stream header.
  const options = {
    version: 'v4',
    action: 'write',
    expires: Date.now() + 15 * 60 * 1000, // 15 minutes
    contentType: 'application/octet-stream',
  };

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

  console.log('Generated PUT signed URL:');
  console.log(url);
  console.log('You can use this URL with any user agent, for example:');
  console.log(
    "curl -X PUT -H 'Content-Type: application/octet-stream' " +
      `--upload-file my-file '${url}'`
  );
}

generateV4UploadSignedUrl().catch(console.error);

PHP

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

use Google\Cloud\Storage\StorageClient;

/**
 * Generate a v4 signed URL for uploading an object.
 *
 * @param string $bucketName The name of your Cloud Storage bucket.
 *        (e.g. 'my-bucket')
 * @param string $objectName The name of your Cloud Storage object.
 *        (e.g. 'my-object')
 */
function upload_object_v4_signed_url(string $bucketName, string $objectName): void
{
    $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'),
        [
            'method' => 'PUT',
            'contentType' => 'application/octet-stream',
            'version' => 'v4',
        ]
    );

    print('Generated PUT signed URL:' . PHP_EOL);
    print($url . PHP_EOL);
    print('You can use this URL with any user agent, for example:' . PHP_EOL);
    print("curl -X PUT -H 'Content-Type: application/octet-stream' " .
        '--upload-file my-file ' . $url . PHP_EOL);
}

Python

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import datetime

from google.cloud import storage


def generate_upload_signed_url_v4(bucket_name, blob_name):
    """Generates a v4 signed URL for uploading a blob using HTTP PUT.

    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 PUT requests using this URL.
        method="PUT",
        content_type="application/octet-stream",
    )

    print("Generated PUT signed URL:")
    print(url)
    print("You can use this URL with any user agent, for example:")
    print(
        "curl -X PUT -H 'Content-Type: application/octet-stream' "
        "--upload-file my-file '{}'".format(url)
    )
    return url

Ruby

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

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

def generate_upload_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: "PUT",
                           expires: storage_expiry_time, version: :v4,
                           headers: { "Content-Type" => "text/plain" }
  puts "Generated PUT signed URL:"
  puts url
  puts "You can use this URL with any user agent, for example:"
  puts "curl -X PUT -H 'Content-Type: text/plain' --upload-file my-file '#{url}'"
end

What's next

• Learn how to sign URLs with your own program.
• Learn more about signed URLs.
• Learn about uploading an object with the XML API.
• Learn about uploading objects.