Usar o Cloud Storage

Use o Cloud Storage para disponibilizar arquivos como filmes, imagens ou outros conteúdos estáticos.

Este documento descreve como usar a Bibliotecas de cliente do Cloud para Cloud Storage no seu app para armazenar e recuperar dados

Antes de começar

Siga as instruções em Como configurar o ambiente de desenvolvimento para configurar o ambiente e o projeto e entender como os aplicativos são estruturados no App Engine. Anote e salve o ID do projeto. Você precisará dele para executar o aplicativo de amostra descrito neste documento.
Certifique-se de criar um bucket do Cloud Storage para o aplicativo invocando o seguinte comando:
```
gcloud storage buckets create gs://<var>YOUR_BUCKET_NAME</var>
```

Configure o bucket como acessível para leitura pública para disponibilização de arquivos:

gcloud storage buckets add-iam-policy-binding gs://<var>YOUR_BUCKET_NAME</var> --member=allUsers --role=roles/storage.objectViewer

Faça o download da amostra

Go

Para clonar o repositório:

git clone https://github.com/GoogleCloudPlatform/golang-samples.git
cd golang-samples/appengine_flexible/storage

Java

Para clonar o repositório:

Versão 11/17

  git clone https://github.com/GoogleCloudPlatform/java-docs-samples
  cd java-docs-samples/flexible/java-11/cloudstorage

Versão 8

  git clone https://github.com/GoogleCloudPlatform/java-docs-samples
  cd java-docs-samples/flexible/java-8/cloudstorage

Node.js

Para clonar o repositório:

git clone https://github.com/GoogleCloudPlatform/nodejs-docs-samples/
cd nodejs-docs-samples/appengine/storage/flexible

PHP

Para clonar o repositório:

git clone https://github.com/GoogleCloudPlatform/php-docs-samples
cd php-docs-samples/appengine/flexible/storage

Python

Para clonar o repositório:

git clone https://github.com/GoogleCloudPlatform/python-docs-samples
cd python-docs-samples/appengine/flexible/storage

Ruby

Para clonar o repositório:

git clone https://github.com/GoogleCloudPlatform/ruby-docs-samples
cd ruby-docs-samples/appengine/flexible/storage/

.NET

Faça o download do aplicativo de amostra e extraia-o.
Se você estiver usando a linha de comando, navegue até o seguinte diretório de aplicativos:
```
    dotnet-docs-samples\appengine\flexible\CloudStorage\CloudStorage.Sample
```

Para executar o aplicativo localmente, configure uma conta de serviço e faça o download das credenciais:

Abra a lista de credenciais no console do Google Cloud.

Abrir a lista de credenciais
Clique em Criar credenciais.
Selecione Chave da conta de serviço.

A janela Criar chave da conta de serviço é exibida.
Clique na lista Conta de serviço e selecione Compute conta de serviço padrão do mecanismo.
Selecione JSON como Tipo de chave.
Clique em Criar.

Uma janela Nova chave privada é exibida e o download da chave privada é realizado automaticamente.
Clique em Fechar.
Observação: ao criar a conta de serviço, escolha Conta de serviço padrão do Compute Engine e deixe JSON selecionado em Tipo de chave.

Edite a configuração do projeto e instale as dependências

Go

Em app.yaml, defina GCLOUD_STORAGE_BUCKET. Esse valor é o nome do bucket do Cloud Storage criado anteriormente.

# Copyright 2019 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

runtime: go
env: flex

runtime_config:
  operating_system: ubuntu22
  runtime_version: 1.21

automatic_scaling:
  min_num_instances: 1

env_variables:
  GCLOUD_STORAGE_BUCKET: your-bucket-name

Java

Em app.yaml, defina BUCKET_NAME como o Cloud Storage criado anteriormente para o projeto.

versão 11/17

runtime: java
env: flex
runtime_config:
  operating_system: ubuntu18
  runtime_version: 11
handlers:
- url: /.*
  script: this field is required, but ignored

env_variables:
  BUCKET_NAME: YOUR-BUCKET-NAME

versão 8

#  Copyright 2023 Google Inc.
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.

runtime: java
env: flex

handlers:
- url: /.*
  script: this field is required, but ignored

env_variables:
  BUCKET_NAME: YOUR-BUCKET-NAME

Em pom.xml, defina com.google.cloud como uma dependência e especifique google-cloud-storage como o artifactID dessa dependência. Isso fornece as funções para usar o Cloud Storage.

versão 11/17

<!--  Using libraries-bom to manage versions.
See https://github.com/GoogleCloudPlatform/cloud-opensource-java/wiki/The-Google-Cloud-Platform-Libraries-BOM -->
<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>com.google.cloud</groupId>
      <artifactId>libraries-bom</artifactId>
      <version>26.32.0</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-dependencies</artifactId>
      <version>${spring.boot.version}</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

<dependencies>
  <dependency>
    <groupId>com.google.cloud</groupId>
    <artifactId>google-cloud-storage</artifactId>
  </dependency>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
  </dependency>
  <dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <type>jar</type>
    <scope>provided</scope>
  </dependency>
  <dependency>
    <groupId>org.junit.vintage</groupId>
    <artifactId>junit-vintage-engine</artifactId>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>org.junit-pioneer</groupId>
    <artifactId>junit-pioneer</artifactId>
    <version>2.2.0</version>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-inline</artifactId>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-junit-jupiter</artifactId>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-test</artifactId>
    <scope>test</scope>
  </dependency>

</dependencies>

Versão 8

<!--  Using libraries-bom to manage versions.
See https://github.com/GoogleCloudPlatform/cloud-opensource-java/wiki/The-Google-Cloud-Platform-Libraries-BOM -->
<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>com.google.cloud</groupId>
      <artifactId>libraries-bom</artifactId>
      <version>26.28.0</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

<dependencies>
  <dependency>
    <groupId>com.google.cloud</groupId>
    <artifactId>google-cloud-storage</artifactId>
  </dependency>
</dependencies>

Node.js

Em app.yaml, adicione o ID do projeto ao valor do ambiente GOOGLE_CLOUD_PROJECT. Em seguida, configure o valor de ambiente GCLOUD_STORAGE_BUCKET para o nome do bucket do Cloud Storage criado anteriormente.

runtime: nodejs
env: flex
runtime_config:
  operating_system: ubuntu22

env_variables:
  GCLOUD_STORAGE_BUCKET: YOUR_BUCKET_NAME

Em package.json, adicione @google-cloud/storage como uma dependência, que fornece as funções para usar o Cloud Storage.

{
  "name": "appengine-storage",
  "description": "Node.js Google Cloud Storage sample for Google App Engine",
  "scripts": {
    "start": "node app.js",
    "test": "c8 mocha -p -j 2 system-test/*.test.js --exit --timeout=30000"
  },
  "engines": {
    "node": ">=16.0.0"
  },
  "dependencies": {
    "@google-cloud/storage": "^7.0.0",
    "express": "^4.18.2",
    "multer": "^1.4.5-lts.1",
    "pug": "^3.0.2"
  },
  "devDependencies": {
    "@types/express": "^4.17.17",
    "@types/multer": "^1.4.7",
    "@types/proxyquire": "^1.3.28",
    "@types/supertest": "^6.0.0",
    "@types/uuid": "^10.0.0",
    "c8": "^10.0.0",
    "mocha": "^10.2.0",
    "proxyquire": "^2.1.3",
    "supertest": "^7.0.0",
    "uuid": "^10.0.0"
  }
}

Consulte o arquivo README.md para instruções sobre como executar e testar localmente.

PHP

Em app.yaml, defina CLOUD_STORAGE_BUCKET. Esse valor é o nome do bucket do Cloud Storage criado anteriormente.

env_variables:
  GOOGLE_STORAGE_BUCKET: "your-bucket-name"

Em composer.json, observe que é preciso incluir a biblioteca de cliente do Cloud, porque isso fornece as funções do Cloud Storage.

{
    "require": {
        "slim/slim": "^4.0",
        "slim/psr7": "^1.3",
        "google/cloud-storage": "^1.0",
        "php-di/slim-bridge": "^3.1"
    }
}

Python

Em app.yaml, defina GOOGLE_STORAGE_BUCKET. Esse valor é o nome do bucket do Cloud Storage criado anteriormente.

env_variables:
  CLOUD_STORAGE_BUCKET: [your-bucket-name]

Em requirements.txt, observe que é preciso incluir a biblioteca google-cloud-storage, porque isso fornece as funções do Cloud Storage.

Flask==3.0.3
google-cloud-storage==2.9.0
gunicorn==22.0.0

Ruby

Em app.yaml, defina GCLOUD_STORAGE_BUCKET como o Cloud Storage criado anteriormente para o projeto.

runtime: ruby
env: flex
entrypoint: bundle exec ruby app.rb

runtime_config:
  operating_system: ubuntu22

env_variables:
  GOOGLE_CLOUD_STORAGE_BUCKET: <your-bucket-name>

É necessário incluir a biblioteca gcloud em Gemfile para usar os recursos do Cloud Storage.

source "https://rubygems.org"

gem "google-cloud-storage"
gem "sinatra"

.NET

No arquivo app.yaml, defina TEST_GOOGLE_BUCKET_NAME como o Cloud Storage criado anteriormente para o projeto.

env_variables:
  TEST_GOOGLE_BUCKET_NAME: [your-bucket-name]

Código do aplicativo

Go

O aplicativo de amostra apresenta uma página da Web que solicita ao usuário um arquivo para armazenar no Cloud Storage. Quando o usuário seleciona um arquivo e clica em enviar, o gerenciador de uploads grava o arquivo no bucket do Cloud Storage usando a função NewWriter do Cloud Storage.

Para recuperar esse arquivo do Cloud Storage, especifique o nome do bucket e o nome do arquivo. Armazene esses valores no app para uso futuro.

// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.


// Sample storage demonstrates use of the cloud.google.com/go/storage package from App Engine flexible environment.
package main

import (
	"context"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/url"
	"os"

	"cloud.google.com/go/storage"
	"google.golang.org/appengine"
)

var (
	storageClient *storage.Client

	// Set this in app.yaml when running in production.
	bucket = os.Getenv("GCLOUD_STORAGE_BUCKET")
)

func main() {
	ctx := context.Background()

	var err error
	storageClient, err = storage.NewClient(ctx)
	if err != nil {
		log.Fatal(err)
	}

	http.HandleFunc("/", formHandler)
	http.HandleFunc("/upload", uploadHandler)

	appengine.Main()
}

func uploadHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method != "POST" {
		http.Error(w, "", http.StatusMethodNotAllowed)
		return
	}

	ctx := appengine.NewContext(r)

	f, fh, err := r.FormFile("file")
	if err != nil {
		msg := fmt.Sprintf("Could not get file: %v", err)
		http.Error(w, msg, http.StatusBadRequest)
		return
	}
	defer f.Close()

	sw := storageClient.Bucket(bucket).Object(fh.Filename).NewWriter(ctx)
	if _, err := io.Copy(sw, f); err != nil {
		msg := fmt.Sprintf("Could not write file: %v", err)
		http.Error(w, msg, http.StatusInternalServerError)
		return
	}

	if err := sw.Close(); err != nil {
		msg := fmt.Sprintf("Could not put file: %v", err)
		http.Error(w, msg, http.StatusInternalServerError)
		return
	}

	u, _ := url.Parse("/" + bucket + "/" + sw.Attrs().Name)

	fmt.Fprintf(w, "Successful! URL: https://storage.googleapis.com%s", u.EscapedPath())
}

func formHandler(w http.ResponseWriter, r *http.Request) {
	fmt.Fprint(w, formHTML)
}

const formHTML = `<!DOCTYPE html>
<html>
  <head>
    <title>Storage</title>
    <meta charset="utf-8">
  </head>
  <body>
    <form method="POST" action="/upload" enctype="multipart/form-data">
      <input type="file" name="file">
      <input type="submit">
    </form>
  </body>
</html>`

Java

O aplicativo de amostra apresenta uma página da Web que solicita ao usuário um arquivo para armazenar no Cloud Storage. Quando o usuário seleciona um arquivo e clica em "Enviar", o gerenciador de solicitações doPost grava o arquivo no bucket do Cloud Storage usando o Storage.create.

Para recuperar esse arquivo do Cloud Storage, especifique o nome do bucket e o nome do arquivo. Armazene esses valores no app para uso futuro.

versão 11/17

@SuppressWarnings("serial")
@WebServlet(name = "upload", value = "/upload")
@MultipartConfig()
public class UploadServlet extends HttpServlet {

  private static final String BUCKET_NAME =
      System.getenv().getOrDefault("BUCKET_NAME", "my-test-bucket");
  private static Storage storage = null;

  public UploadServlet() {
    storage = StorageOptions.getDefaultInstance().getService();
  }

  @Override
  public void doPost(HttpServletRequest req, HttpServletResponse resp)
      throws IOException, ServletException {
    final Part filePart = req.getPart("file");
    final String fileName = filePart.getSubmittedFileName();
    // Modify access list to allow all users with link to read file
    List<Acl> acls = new ArrayList<>();
    acls.add(Acl.of(Acl.User.ofAllUsers(), Acl.Role.READER));
    // the inputstream is closed by default, so we don't need to close it here
    Blob blob =
        storage.create(
            BlobInfo.newBuilder(BUCKET_NAME, fileName).setAcl(acls).build(),
            filePart.getInputStream());

    // return the public download link
    resp.getWriter().print(blob.getMediaLink());
  }
}

Versão 8

@SuppressWarnings("serial")
@WebServlet(name = "upload", value = "/upload")
@MultipartConfig()
public class UploadServlet extends HttpServlet {

  private static final String BUCKET_NAME = System.getenv("BUCKET_NAME");
  private static Storage storage = null;

  @Override
  public void init() {
    storage = StorageOptions.getDefaultInstance().getService();
  }

  @Override
  public void doPost(HttpServletRequest req, HttpServletResponse resp)
      throws IOException, ServletException {
    final Part filePart = req.getPart("file");
    final String fileName = filePart.getSubmittedFileName();

    // Modify access list to allow all users with link to read file
    List<Acl> acls = new ArrayList<>();
    acls.add(Acl.of(Acl.User.ofAllUsers(), Acl.Role.READER));
    // the inputstream is closed by default, so we don't need to close it here
    Blob blob =
        storage.create(
            BlobInfo.newBuilder(BUCKET_NAME, fileName).setAcl(acls).build(),
            filePart.getInputStream());

    // return the public download link
    resp.getWriter().print(blob.getMediaLink());
  }
}

Node.js

O aplicativo de amostra apresenta uma página da Web que solicita ao usuário um arquivo para armazenar no Cloud Storage. Depois que o usuário seleciona o arquivo e clica em enviar, o gerenciador de upload carrega o conteúdo do arquivo em um blob e o salva no Cloud Storage.

Após o upload do arquivo no Cloud Storage, o URL público dele é retornado. É possível usá-lo para disponibilizar o arquivo diretamente do Cloud Storage. Armazene esse valor no app para uso futuro.

const {format} = require('util');
const express = require('express');
const Multer = require('multer');

// By default, the client will authenticate using the service account file
// specified by the GOOGLE_APPLICATION_CREDENTIALS environment variable and use
// the project specified by the GOOGLE_CLOUD_PROJECT environment variable. See
// https://github.com/GoogleCloudPlatform/google-cloud-node/blob/master/docs/authentication.md
// These environment variables are set automatically on Google App Engine
const {Storage} = require('@google-cloud/storage');

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

const app = express();
app.set('view engine', 'pug');

// This middleware is available in Express v4.16.0 onwards
app.use(express.json());

// Multer is required to process file uploads and make them available via
// req.files.
const multer = Multer({
  storage: Multer.memoryStorage(),
  limits: {
    fileSize: 5 * 1024 * 1024, // no larger than 5mb, you can change as needed.
  },
});

// A bucket is a container for objects (files).
const bucket = storage.bucket(process.env.GCLOUD_STORAGE_BUCKET);

// Display a form for uploading files.
app.get('/', (req, res) => {
  res.render('form.pug');
});

// Process the file upload and upload to Google Cloud Storage.
app.post('/upload', multer.single('file'), (req, res, next) => {
  if (!req.file) {
    res.status(400).send('No file uploaded.');
    return;
  }

  // Create a new blob in the bucket and upload the file data.
  const blob = bucket.file(req.file.originalname);
  const blobStream = blob.createWriteStream();

  blobStream.on('error', err => {
    next(err);
  });

  blobStream.on('finish', () => {
    // The public URL can be used to directly access the file via HTTP.
    const publicUrl = format(
      `https://storage.googleapis.com/${bucket.name}/${blob.name}`
    );
    res.status(200).send(publicUrl);
  });

  blobStream.end(req.file.buffer);
});

const PORT = parseInt(process.env.PORT) || 8080;
app.listen(PORT, () => {
  console.log(`App listening on port ${PORT}`);
  console.log('Press Ctrl+C to quit.');
});

PHP

use DI\Container;
use Google\Cloud\Storage\StorageClient;
use Psr\Http\Message\ServerRequestInterface as Request;
use Psr\Http\Message\ResponseInterface as Response;
use Slim\Factory\AppFactory;

// Create App
AppFactory::setContainer($container = new Container());
$app = AppFactory::create();

// Display errors
$app->addErrorMiddleware(true, true, true);

$container = $app->getContainer();

$app->get('/', function (Request $request, Response $response) use ($container) {
    /** @var Google\Cloud\StorageClient */
    $storage = $container->get('storage');
    $bucketName = $container->get('bucket_name');
    $objectName = $container->get('object_name');
    $bucket = $storage->bucket($bucketName);
    $object = $bucket->object($objectName);
    $content = $object->exists() ? $object->downloadAsString() : '';
    $escapedContent = htmlspecialchars($content);
    $response->getBody()->write(<<<EOF
    <h1>Storage Example</h1>
    <h3>Write [<a href="https://cloud.google.com/appengine/docs/flexible/php/using-cloud-storage">docs</a>]:</h3>
    <form action="/write" method="post">
        Some file content:<br />
        <textarea name="content"></textarea><br />
        <input type="submit" />
    </form>
EOF
    );
    if ($content) {
        $response->getBody()->write(
            "<p><strong>Your content:</strong><p><p>$escapedContent</p>"
        );
    }
    return $response;
});

/**
 * Write to a Storage bucket.
 * @see https://cloud.google.com/appengine/docs/flexible/php/using-cloud-storage
 */
$app->post('/write', function (Request $request, Response $response) use ($container) {
    /** @var Google\Cloud\StorageClient */
    $storage = $container->get('storage');
    $bucketName = $container->get('bucket_name');
    $objectName = $container->get('object_name');
    parse_str((string) $request->getBody(), $postData);
    $metadata = ['contentType' => 'text/plain'];
    $storage->bucket($bucketName)->upload($postData['content'] ?? '', [
        'name' => $objectName,
        'metadata' => $metadata,
    ]);
    return $response
        ->withStatus(302)
        ->withHeader('Location', '/');
});

$container->set('storage', function () use ($container) {
    $projectId = $container->get('project_id');
    $storage = new StorageClient([
        'projectId' => $projectId
    ]);
    return $storage;
});

Python

O aplicativo de amostra apresenta uma página da Web que solicita ao usuário um arquivo para armazenar no Cloud Storage. Quando o usuário seleciona um arquivo e clica em "Enviar", o gerenciador de uploads carrega o conteúdo do arquivo em blob e o grava no bucket (links em inglês) do Cloud Storage.

from __future__ import annotations

import logging
import os

from flask import Flask, request
from google.cloud import storage

app = Flask(__name__)

# Configure this environment variable via app.yaml
CLOUD_STORAGE_BUCKET = os.environ["CLOUD_STORAGE_BUCKET"]


@app.route("/")
def index() -> str:
    return """
<form method="POST" action="/upload" enctype="multipart/form-data">
    <input type="file" name="file">
    <input type="submit">
</form>
"""


@app.route("/upload", methods=["POST"])
def upload() -> str:
    """Process the uploaded file and upload it to Google Cloud Storage."""
    uploaded_file = request.files.get("file")

    if not uploaded_file:
        return "No file uploaded.", 400

    # Create a Cloud Storage client.
    gcs = storage.Client()

    # Get the bucket that the file will be uploaded to.
    bucket = gcs.get_bucket(CLOUD_STORAGE_BUCKET)

    # Create a new blob and upload the file's content.
    blob = bucket.blob(uploaded_file.filename)

    blob.upload_from_string(
        uploaded_file.read(), content_type=uploaded_file.content_type
    )

    # Make the blob public. This is not necessary if the
    # entire bucket is public.
    # See https://cloud.google.com/storage/docs/access-control/making-data-public.
    blob.make_public()

    # The public URL can be used to directly access the uploaded file via HTTP.
    return blob.public_url


@app.errorhandler(500)
def server_error(e: Exception | int) -> str:
    logging.exception("An error occurred during a request.")
    return (
        """
    An internal error occurred: <pre>{}</pre>
    See logs for full stacktrace.
    """.format(
            e
        ),
        500,
    )


if __name__ == "__main__":
    # This is used when running locally. Gunicorn is used to run the
    # application on Google App Engine. See entrypoint in app.yaml.
    app.run(host="127.0.0.1", port=8080, debug=True)

Ruby

require "sinatra"
require "google/cloud/storage"

storage = Google::Cloud::Storage.new
bucket  = storage.bucket ENV["GOOGLE_CLOUD_STORAGE_BUCKET"]

get "/" do
  # Present the user with an upload form
  '
    <form method="POST" action="/upload" enctype="multipart/form-data">
      <input type="file" name="file">
      <input type="submit" value="Upload">
    </form>
  '
end

post "/upload" do
  file_path = params[:file][:tempfile].path
  file_name = params[:file][:filename]

  # Upload file to Google Cloud Storage bucket
  file = bucket.create_file file_path, file_name, acl: "public"

  # The public URL can be used to directly access the uploaded file via HTTP
  file.public_url
end

.NET

    public class HomeController : Controller
    {
        // Contains the bucket name and object name
        readonly CloudStorageOptions _options;
        // The Google Cloud Storage client.
        readonly StorageClient _storage;

        public HomeController(CloudStorageOptions options)
        {
            _options = options;
            _storage = StorageClient.Create();
        }

        [HttpGet]
        public async Task<IActionResult> Index()
        {
            var model = new HomeIndex();
            if (new string[] { null, "", "your-google-bucket-name" }
                .Contains(_options.BucketName))
            {
                model.MissingBucketName = true;
                return View(model);
            }
            try
            {
                // Get the storage object.
                var storageObject =
                    await _storage.GetObjectAsync(_options.BucketName, _options.ObjectName);
                // Get a direct link to the storage object.
                model.MediaLink = storageObject.MediaLink;
                // Download the storage object.
                MemoryStream m = new MemoryStream();
                await _storage.DownloadObjectAsync(
                    _options.BucketName, _options.ObjectName, m);
                m.Seek(0, SeekOrigin.Begin);
                byte[] content = new byte[m.Length];
                m.Read(content, 0, content.Length);
                model.Content = Encoding.UTF8.GetString(content);
            }
            catch (GoogleApiException e)
            when (e.HttpStatusCode == System.Net.HttpStatusCode.NotFound)
            {
                // Does not exist yet.  No problem.
            }
            return View(model);
        }

        [HttpPost]
        public async Task<IActionResult> Index(Form sendForm)
        {
            var model = new HomeIndex();
            // Take the content uploaded in the form and upload it to
            // Google Cloud Storage.
            await _storage.UploadObjectAsync(
                _options.BucketName, _options.ObjectName, "text/plain",
                new MemoryStream(Encoding.UTF8.GetBytes(sendForm.Content)));
            model.Content = sendForm.Content;
            model.SavedNewContent = true;
            var storageObject =
                await _storage.GetObjectAsync(_options.BucketName, _options.ObjectName);
            model.MediaLink = storageObject.MediaLink;
            return View(model);
        }

Para mais informações

Consulte a documentação do Cloud Storage para informações completas.