Proceso de firma V4 con herramientas de Cloud Storage

En esta página, se describe cómo usar gsutil y las bibliotecas cliente de Cloud Storage para generar fácilmente URL firmadas. Estas URL otorgan acceso de lectura o escritura por tiempo limitado a un recurso específico de Cloud Storage. Cualquier persona que cuente con la URL firmada podrá usarla mientras está activa, independientemente de si tiene una Cuenta de Google. Para obtener más información sobre las URL firmadas, consulta la Descripción general de las URL firmadas . Para crear URL firmadas por tu cuenta, consulta el Proceso de firma V4 con tu propio programa.

Para generar una URL firmada, sigue estos pasos:

gsutil

  1. Genera una clave privada nueva o usa una existente para una cuenta de servicio. La clave puede estar en formato JSON o PKCS12.

    Para obtener más información sobre las claves privadas y cuentas de servicio, consulta Cuentas de servicio.

  2. Usa el comando gsutil signurl, pasa la ruta de acceso a la clave privada del paso anterior y el nombre del depósito o del objeto para el que deseas generar una URL firmada.

    Por ejemplo, si usas una clave almacenada en la carpeta Desktop, el siguiente comando generará una URL firmada para que los usuarios vean el objeto cat.jpeg durante 10 minutos.

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

Si se realiza con éxito, la respuesta debería verse de la siguiente manera:

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

La URL firmada es la string que comienza con https://storage.googleapis.com, y es probable que se extienda varias líneas. Cualquier persona puede usar la URL a fin de acceder al recurso asociado (en este caso, cat.jpeg) durante el marco de tiempo designado (en este caso, 10 minutos).

Muestras de código

C++

Si deseas obtener más información, consulta la documentación de referencia de la API de Cloud Storage para C++.

En la siguiente muestra, se crea una URL firmada que puede obtener un objeto de un depósito:

namespace gcs = google::cloud::storage;
using ::google::cloud::StatusOr;
[](gcs::Client client, std::string bucket_name, std::string 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";
}

En la siguiente muestra, se crea una URL firmada que puede subir un objeto a un depósito:

namespace gcs = google::cloud::storage;
using ::google::cloud::StatusOr;
[](gcs::Client client, std::string bucket_name, std::string 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#

Si deseas obtener más información, consulta la documentación de referencia de la API de Cloud Storage para C#.

En la siguiente muestra, se crea una URL firmada que puede obtener un objeto de un depósito:

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}'");
}

En el siguiente ejemplo, se crea una URL firmada que puede subir un objeto a un depósito:

        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

Si deseas obtener más información, consulta la documentación de referencia de la API de Cloud Storage para Go.

En la siguiente muestra, se crea una URL firmada que puede obtener un objeto de un depósito:

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)

En el siguiente ejemplo, se crea una URL firmada que puede subir un objeto a un depósito:

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

Java

Si deseas obtener más información, consulta la documentación de referencia de la API de Cloud Storage para Java.

En la siguiente muestra, se crea una URL firmada que puede obtener un objeto de un depósito:

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 {
  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();

    /**
     * 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.
     */
    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 + "'");
  }
}

En la siguiente muestra, se crea una URL firmada que puede subir un objeto a un depósito:

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 {
  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");

    /**
     * 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.
     */
    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

Si deseas obtener más información, consulta la documentación de referencia de la API de Cloud Storage para Node.js.

En la siguiente muestra, se crea una URL firmada que puede obtener un objeto de un depósito:

/**
 * 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 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);

En la siguiente muestra, se crea una URL firmada que puede subir un objeto a un depósito:

/**
 * 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

Si deseas obtener más información, consulta la documentación de referencia de la API de Cloud Storage para PHP.

En la siguiente muestra, se crea una URL firmada que puede obtener un objeto de un depósito:

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);
}

En el siguiente ejemplo, se crea una URL firmada que puede subir un objeto a un depósito:

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

Si deseas obtener más información, consulta la documentación de referencia de la API de Cloud Storage para Python.

En la siguiente muestra, se crea una URL firmada que puede obtener un objeto de un depósito:

from google.cloud import storage
import datetime

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

En la siguiente muestra, se crea una URL firmada que puede subir un objeto a un depósito:

from google.cloud import storage
import datetime

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

Si deseas obtener más información, consulta la documentación de referencia de la API de Cloud Storage para Ruby.

En la siguiente muestra, se crea una URL firmada que puede obtener un objeto de un depósito:

# 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}"

En el siguiente ejemplo, se crea una URL firmada que puede subir un objeto a un depósito:

# 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}'"