Cloud Storage のツールを使用した V4 署名プロセス

このページでは、gsutil と Cloud Storage クライアント ライブラリを使用して署名付き URL を簡単に生成する方法について説明します。署名付き URL は、特定の Cloud Storage リソースへの期限付きの読み取りまたは書き込みアクセスを提供します。署名付き URL は、その URL を所有する全員が、Google アカウントを持っているかどうかにかかわらず、URL がアクティブである限り使用できます。署名付き URL の詳細については、署名付き URL の概要をご覧ください。自分で署名付き URL を作成するには、独自プログラムによる V4 署名プロセスをご覧ください。

署名付き URL を生成するには、次の手順を行います。

gsutil

  1. 新しい秘密鍵を生成するか、サービス アカウント用の既存の秘密鍵を使用します。鍵は、JSON 形式か PKCS12 形式のものを使用できます。

    秘密鍵とサービス アカウントについて詳しくは、サービス アカウントをご覧ください。

  2. gsutil signurl コマンドを使用して、前のステップで準備した秘密鍵へのパスと、署名付き URL を生成するバケットまたはオブジェクトの名前を渡します。

    たとえば、次のコマンドでは、フォルダ Desktop に保存されている鍵を使用して、オブジェクト cat.jpeg を 10 分間ユーザーが参照できるようにするための署名付き URL が生成されます。

    gsutil signurl -d 10m Desktop/private-key.json gs://example-bucket/cat.jpeg

成功すると、レスポンスは次のようになります。

URL    HTTP Method    Expiration    Signed URL
gs://example-bucket/cat.jpeg GET 2018-10-26 15:19:52 https://storage.googleapis.
com/example-bucket/cat.jpeg?x-goog-signature=2d2a6f5055eb004b8690b9479883292ae74
50cdc15f17d7f99bc49b916f9e7429106ed7e5858ae6b4ab0bbbdb1a8ccc364dad3a0da2caebd308
87a70c5b2569d089ceb8afbde3eed4dff5086f0db5483998c175980991fe899fbd2cd8cb813b0016
5e8d56e0a8aa7b3d7a12ee1baa8400611040f05b50a1a8eab5ba223fe1375747748de950ec7a4dc5
0f8382a6ffd4994ac42498d7daa703d9a414d4475154d0e7edaa92d4f2507d92c1f7e8efa7cab64d
f68b5df48575b9259d8d0bdb5dc752bdf07bd162d98ff2924f2e4a26fa6b3cede73ad5333c47d146
a21c2ab2d97115986a12c68ff37346d6c2ca83e56b8ec8ad95632710b489b75c35697d781c38e&
x-goog-algorithm=GOOG4-RSA-SHA256&x-goog-credential=example%40example-project.
iam.gserviceaccount.com%2F20181026%2Fus%2Fstorage%2Fgoog4_request&x-goog-date=
20181026T211942Z&x-goog-expires=3600&x-goog-signedheaders=host

署名付き URL は https://storage.googleapis.com で始まる文字列であり、数行にわたる可能性があります。この URL を使用すると、設定した時間枠内の間(この例では 10 分)、関連付けられたリソース(この例では cat.jpeg)に誰でもアクセスできます。

コードサンプル

C++

詳細については、Cloud Storage C++ API のリファレンス ドキュメントをご覧ください。

次のサンプルは、バケットからオブジェクトを取得できる署名付き URL を作成します。

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

  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";
}

次のサンプルは、オブジェクトをバケットにアップロードできる署名付き URL を作成します。

namespace gcs = google::cloud::storage;
using ::google::cloud::StatusOr;
[](gcs::Client client, std::string const& bucket_name,
   std::string const& object_name) {
  StatusOr<std::string> signed_url = client.CreateV4SignedUrl(
      "PUT", std::move(bucket_name), std::move(object_name),
      gcs::SignedUrlDuration(std::chrono::minutes(15)),
      gcs::AddExtensionHeader("content-type", "application/octet-stream"));

  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 -X PUT -H 'Content-Type: application/octet-stream'"
            << " --upload-file my-file '" << *signed_url << "'\n";
}

C#

詳細については、Cloud Storage C# API のリファレンス ドキュメントをご覧ください。

次のサンプルは、バケットからオブジェクトを取得できる署名付き URL を作成します。

private void GenerateV4SignedGetUrl(string bucketName, string objectName)
{
    UrlSigner urlSigner = UrlSigner
        .FromServiceAccountPath(Environment.GetEnvironmentVariable("GOOGLE_APPLICATION_CREDENTIALS"));
    string url = urlSigner.Sign(bucketName, objectName, TimeSpan.FromHours(1), HttpMethod.Get, SigningVersion.V4);
    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}'");
}

次のサンプルは、オブジェクトをバケットにアップロードできる署名付き URL を作成します。

        private void GenerateV4SignedPutUrl(string bucketName, string objectName)
        {
            UrlSigner urlSigner = UrlSigner
                .FromServiceAccountPath(Environment.GetEnvironmentVariable("GOOGLE_APPLICATION_CREDENTIALS"));

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

            UrlSigner.Options options = UrlSigner.Options
                .FromDuration(TimeSpan.FromHours(1))
                .WithSigningVersion(SigningVersion.V4);
            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}'");
        }

Go

詳細については、Cloud Storage Go API のリファレンス ドキュメントをご覧ください。

次のサンプルは、バケットからオブジェクトを取得できる署名付き URL を作成します。

import (
	"fmt"
	"io"
	"io/ioutil"
	"time"

	"cloud.google.com/go/storage"
	"golang.org/x/oauth2/google"
)

// generateV4GetObjectSignedURL generates object signed URL with GET method.
func generateV4GetObjectSignedURL(w io.Writer, bucket, object, serviceAccount string) (string, error) {
	// bucket := "bucket-name"
	// object := "object-name"
	// serviceAccount := "service_account.json"
	jsonKey, err := ioutil.ReadFile(serviceAccount)
	if err != nil {
		return "", fmt.Errorf("ioutil.ReadFile: %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(bucket, object, opts)
	if err != nil {
		return "", fmt.Errorf("storage.SignedURL: %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)
	return u, nil
}

次のサンプルは、オブジェクトをバケットにアップロードできる署名付き URL を作成します。

import (
	"fmt"
	"io"
	"io/ioutil"
	"time"

	"cloud.google.com/go/storage"
	"golang.org/x/oauth2/google"
)

// generateV4PutObjectSignedURL generates object signed URL with PUT method.
func generateV4PutObjectSignedURL(w io.Writer, bucket, object, serviceAccount string) (string, error) {
	// bucket := "bucket-name"
	// object := "object-name"
	// serviceAccount := "service_account.json"
	jsonKey, err := ioutil.ReadFile(serviceAccount)
	if err != nil {
		return "", fmt.Errorf("ioutil.ReadFile: %v", err)
	}
	conf, err := google.JWTConfigFromJSON(jsonKey)
	if err != nil {
		return "", fmt.Errorf("google.JWTConfigFromJSON: %v", err)
	}
	opts := &storage.SignedURLOptions{
		Scheme: storage.SigningSchemeV4,
		Method: "PUT",
		Headers: []string{
			"Content-Type:application/octet-stream",
		},
		GoogleAccessID: conf.Email,
		PrivateKey:     conf.PrivateKey,
		Expires:        time.Now().Add(15 * time.Minute),
	}
	u, err := storage.SignedURL(bucket, object, opts)
	if err != nil {
		return "", fmt.Errorf("storage.SignedURL: %v", 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

詳細については、Cloud Storage Java API のリファレンス ドキュメントをご覧ください。

次のサンプルは、バケットからオブジェクトを取得できる署名付き URL を作成します。

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 + "'");
  }
}

次のサンプルは、オブジェクトをバケットにアップロードできる署名付き URL を作成します。

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 generateV4GPutObjectSignedUrl(
      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

詳細については、Cloud Storage Node.js API のリファレンス ドキュメントをご覧ください。

次のサンプルは、バケットからオブジェクトを取得できる署名付き URL を作成します。

/**
 * 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.
 */
// const bucketName = 'Name of a bucket, e.g. my-bucket';
// const filename = 'File to access, e.g. file.txt';

// 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);

次のサンプルは、オブジェクトをバケットにアップロードできる署名付き URL を作成します。

/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// const bucketName = 'Name of a bucket, e.g. my-bucket';
// const filename = 'File to access, e.g. file.txt';

// 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

詳細については、Cloud Storage PHP API のリファレンス ドキュメントをご覧ください。

次のサンプルは、バケットからオブジェクトを取得できる署名付き URL を作成します。

use Google\Cloud\Storage\StorageClient;

/**
 * Generate a v4 signed URL for downloading an object.
 *
 * @param string $bucketName the name of your Google Cloud bucket.
 * @param string $objectName the name of your Google Cloud object.
 *
 * @return void
 */
function get_object_v4_signed_url($bucketName, $objectName)
{
    $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);
}

次のサンプルは、オブジェクトをバケットにアップロードできる署名付き URL を作成します。

use Google\Cloud\Storage\StorageClient;

/**
 * Generate a v4 signed URL for uploading an object.
 *
 * @param string $bucketName the name of your Google Cloud bucket.
 * @param string $objectName the name of your Google Cloud object.
 *
 * @return void
 */
function upload_object_v4_signed_url($bucketName, $objectName)
{
    $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

詳細については、Cloud Storage Python API のリファレンス ドキュメントをご覧ください。

次のサンプルは、バケットからオブジェクトを取得できる署名付き URL を作成します。

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

次のサンプルは、オブジェクトをバケットにアップロードできる署名付き URL を作成します。

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

詳細については、Cloud Storage Ruby API のリファレンス ドキュメントをご覧ください。

次のサンプルは、バケットからオブジェクトを取得できる署名付き URL を作成します。

# bucket_name = "Your Google Cloud Storage bucket name"
# file_name   = "Name of a file in the Google Cloud Storage bucket"
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}"

次のサンプルは、オブジェクトをバケットにアップロードできる署名付き URL を作成します。

# bucket_name = "Your Google Cloud Storage bucket name"
# file_name   = "Name of a file in the Cloud Storage bucket"
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}'"