Download all object contents into memory.

Download all object contents into memory.

Explore further

For detailed documentation that includes this code sample, see the following:

• Download objects into memory

Code sample

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 client libraries.

namespace gcs = ::google::cloud::storage;
[](gcs::Client client, std::string const& bucket_name,
   std::string const& object_name) {
  gcs::ObjectReadStream stream = client.ReadObject(bucket_name, object_name);
  std::string buffer{std::istream_iterator<char>(stream),
                     std::istream_iterator<char>()};
  if (stream.bad()) throw google::cloud::Status(stream.status());

  std::cout << "The object has " << buffer.size() << " characters\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 client libraries.

using Google.Cloud.Storage.V1;
using System;
using System.IO;

public class DownloadObjectIntoMemorySample
{
    public Stream DownloadObjectIntoMemory(
        string bucketName = "unique-bucket-name",
        string objectName = "file-name")
    {
        var storage = StorageClient.Create();
        Stream stream = new MemoryStream();
        storage.DownloadObject(bucketName, objectName, stream);

        Console.WriteLine($"The contents of {objectName} from bucket {bucketName} are downloaded");
        return stream;
    }
}

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 client libraries.

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

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

// downloadFileIntoMemory downloads an object.
func downloadFileIntoMemory(w io.Writer, bucket, object string) ([]byte, error) {
	// bucket := "bucket-name"
	// object := "object-name"
	ctx := context.Background()
	client, err := storage.NewClient(ctx)
	if err != nil {
		return nil, fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close()

	ctx, cancel := context.WithTimeout(ctx, time.Second*50)
	defer cancel()

	rc, err := client.Bucket(bucket).Object(object).NewReader(ctx)
	if err != nil {
		return nil, fmt.Errorf("Object(%q).NewReader: %w", object, err)
	}
	defer rc.Close()

	data, err := io.ReadAll(rc)
	if err != nil {
		return nil, fmt.Errorf("io.ReadAll: %w", err)
	}
	fmt.Fprintf(w, "Blob %v downloaded.\n", object)
	return data, 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 client libraries.

import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;
import java.nio.charset.StandardCharsets;

public class DownloadObjectIntoMemory {
  public static void downloadObjectIntoMemory(
      String projectId, String bucketName, String objectName) {
    // The ID of your GCP project
    // String projectId = "your-project-id";

    // The ID of your GCS bucket
    // String bucketName = "your-unique-bucket-name";

    // The ID of your GCS object
    // String objectName = "your-object-name";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();
    byte[] content = storage.readAllBytes(bucketName, objectName);
    System.out.println(
        "The contents of "
            + objectName
            + " from bucket name "
            + bucketName
            + " are: "
            + new String(content, StandardCharsets.UTF_8));
  }
}

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 client libraries.

/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// The ID of your GCS bucket
// const bucketName = 'your-unique-bucket-name';

// The ID of your GCS file
// 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 downloadIntoMemory() {
  // Downloads the file into a buffer in memory.
  const contents = await storage.bucket(bucketName).file(fileName).download();

  console.log(
    `Contents of gs://${bucketName}/${fileName} are ${contents.toString()}.`
  );
}

downloadIntoMemory().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 client libraries.

use Google\Cloud\Storage\StorageClient;

/**
 * Download an object from Cloud Storage and save into a buffer in memory.
 *
 * @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 download_object_into_memory(
    string $bucketName,
    string $objectName
): void {
    $storage = new StorageClient();
    $bucket = $storage->bucket($bucketName);
    $object = $bucket->object($objectName);
    $contents = $object->downloadAsString();
    printf(
        'Downloaded %s from gs://%s/%s' . PHP_EOL,
        $contents,
        $bucketName,
        $objectName
    );
}

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 client libraries.

from google.cloud import storage


def download_blob_into_memory(bucket_name, blob_name):
    """Downloads a blob into memory."""
    # The ID of your GCS bucket
    # bucket_name = "your-bucket-name"

    # The ID of your GCS object
    # blob_name = "storage-object-name"

    storage_client = storage.Client()

    bucket = storage_client.bucket(bucket_name)

    # Construct a client side representation of a blob.
    # Note `Bucket.blob` differs from `Bucket.get_blob` as it doesn't retrieve
    # any content from Google Cloud Storage. As we don't need additional data,
    # using `Bucket.blob` is preferred here.
    blob = bucket.blob(blob_name)
    contents = blob.download_as_bytes()

    print(
        "Downloaded storage object {} from bucket {} as the following bytes object: {}.".format(
            blob_name, bucket_name, contents.decode("utf-8")
        )
    )

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 client libraries.

# The name of the bucket to access
# bucket_name = "my-bucket"

# The name of the remote file to download
# file_name = "file.txt"

require "google/cloud/storage"

storage = Google::Cloud::Storage.new
bucket  = storage.bucket bucket_name, skip_lookup: true
file    = bucket.file file_name

downloaded = file.download
downloaded.rewind # Optional - not needed on first read
contents = downloaded.read

puts "Contents of storage object #{file.name} in bucket #{bucket_name} are: #{contents}"

What's next

To search and filter code samples for other Google Cloud products, see the Google Cloud sample browser.