Introduction to the Admin Cloud Storage API

Cloud Storage for Firebase stores your data in a Google Cloud Storage bucket — an exabyte scale object storage solution with high availability and global redundancy. The Firebase Admin SDK allows you to directly access your Cloud Storage buckets from privileged environments. Then you can use Google Cloud Storage APIs to manipulate the objects stored in the buckets.

The Admin SDK also lets you to create shareable URLs so users can download objects in your buckets.

Use a default bucket

You can specify a default bucket name when initializing the Admin SDK. Then you can retrieve an authenticated reference to this bucket.

The bucket name must not contain gs:// or any other protocol prefixes. For example, if the bucket URL displayed in the Firebase console is gs://PROJECT_ID.firebasestorage.app, pass the string PROJECT_ID.firebasestorage.app to the Admin SDK.

Node.js

const { initializeApp, cert } = require('firebase-admin/app');
const { getStorage } = require('firebase-admin/storage');

const serviceAccount = require('./path/to/serviceAccountKey.json');

initializeApp({
  credential: cert(serviceAccount),
  storageBucket: '<BUCKET_NAME>.appspot.com'
});

const bucket = getStorage().bucket();

// 'bucket' is an object defined in the @google-cloud/storage library.
// See https://googlecloudplatform.github.io/google-cloud-node/#/docs/storage/latest/storage/bucket
// for more details.

Java

FileInputStream serviceAccount = new FileInputStream("path/to/serviceAccountKey.json");

FirebaseOptions options = FirebaseOptions.builder()
    .setCredentials(GoogleCredentials.fromStream(serviceAccount))
    .setStorageBucket("<BUCKET_NAME>.appspot.com")
    .build();
FirebaseApp.initializeApp(options);

Bucket bucket = StorageClient.getInstance().bucket();

// 'bucket' is an object defined in the google-cloud-storage Java library.
// See https://cloud.google.com/java/docs/reference/google-cloud-storage/latest/com.google.cloud.storage.Bucket
// for more details.

Python

import firebase_admin
from firebase_admin import credentials
from firebase_admin import storage

cred = credentials.Certificate('path/to/serviceAccountKey.json')
firebase_admin.initialize_app(cred, {
    'storageBucket': 'PROJECT_ID.firebasestorage.app'
})

bucket = storage.bucket()

# 'bucket' is an object defined in the google-cloud-storage Python library.
# See https://googlecloudplatform.github.io/google-cloud-python/latest/storage/buckets.html
# for more details.

Go

import (
	"context"
	"log"

	firebase "firebase.google.com/go/v4"
	"firebase.google.com/go/v4/auth"
	"google.golang.org/api/option"
)

config := &firebase.Config{
	StorageBucket: "<BUCKET_NAME>.appspot.com",
}
opt := option.WithCredentialsFile("path/to/serviceAccountKey.json")
app, err := firebase.NewApp(context.Background(), config, opt)
if err != nil {
	log.Fatalln(err)
}

client, err := app.Storage(context.Background())
if err != nil {
	log.Fatalln(err)
}

bucket, err := client.DefaultBucket()
if err != nil {
	log.Fatalln(err)
}
// 'bucket' is an object defined in the cloud.google.com/go/storage package.
// See https://godoc.org/cloud.google.com/go/storage#BucketHandle
// for more details.
storage.go

You can use the bucket references returned by the Admin SDK in conjunction with the official Google Cloud Storage client libraries to upload, download, and modify content in the buckets associated with your Firebase projects. Note that you do not have to authenticate Google Cloud Storage libraries when using the Firebase Admin SDK. The bucket references returned by the Admin SDK are already authenticated with the credentials used to initialize your Firebase app.

Use custom buckets

If you want to use a Cloud Storage bucket other than the default bucket described earlier in this guide, or use multiple Cloud Storage buckets in a single app, you can retrieve a reference to a custom bucket:

Node.js

const bucket = getStorage().bucket('my-custom-bucket');

Java

Bucket bucket = StorageClient.getInstance().bucket("my-custom-bucket");

Python

bucket = storage.bucket('my-custom-bucket')

Go

 bucket, err := client.Bucket("my-custom-bucket")
storage.go

Use a custom Firebase app

If you are building a more complicated application that interacts with multiple Firebase apps, you can access the Cloud Storage buckets associated with a specific Firebase app as follows:

Node.js

const bucket = getStorage(customApp).bucket();

Java

Bucket bucket = StorageClient.getInstance(customApp).bucket();

Python

bucket = storage.bucket(app=custom_app)

Go

otherClient, err := otherApp.Storage(context.Background())
bucket, err := otherClient.Bucket("other-app-bucket")

Get a shareable download URL

You can use the Admin SDK to generate a non-expiring download URL for files stored in your buckets. Anyone with this URL can permanently access the file.

Node.js

const { getStorage, getDownloadURL } = require('firebase-admin/storage');

const fileRef = getStorage().bucket('my-bucket').file('my-file');
const downloadURL= await getDownloadURL(fileRef);

Google Cloud Storage client libraries

The Firebase Admin SDKs depend on the Google Cloud Storage client libraries to provide Cloud Storage access. The bucket references returned by the Admin SDK are objects defined in these libraries. Refer to the documentation and API references of the Google Cloud Storage client libraries to learn how to use the returned bucket references in use cases like file upload and download.