Get Started with Cloud Storage for C++

Cloud Storage for Firebase lets you upload and share user generated content, such as images and video, which allows you to build rich media content into your apps. Your data is stored in a Google Cloud Storage bucket, an exabyte scale object storage solution with high availability and global redundancy. Cloud Storage lets you securely upload these files directly from mobile devices and web browsers, handling spotty networks with ease.

Before you begin

Before you can use Cloud Storage, you need to:

  • Register your C++ project and configure it to use Firebase.

    If your C++ project already uses Firebase, then it's already registered and configured for Firebase.

  • In your project-level build.gradle file, make sure to include Google's Maven repository in both your buildscript and allprojects sections.

  • Add the Firebase C++ SDK to your C++ project.

Note that adding Firebase to your C++ project involves tasks both in the Firebase console and in your open C++ project (for example, you download Firebase config files from the console, then move them into your C++ project).

Create a default Storage bucket

  1. From the navigation pane of the Firebase console, select Storage, then click Get started.

  2. Review the messaging about securing your Storage data using security rules. During development, consider setting up your rules for public access.

  3. Select a location for your default Storage bucket.

    • This location setting is your project's default Google Cloud Platform (GCP) resource location. Note that this location will be used for GCP services in your project that require a location setting, specifically, your Cloud Firestore database and your App Engine app (which is required if you use Cloud Scheduler).

    • If you aren't able to select a location, then your project already has a default GCP resource location. It was set either during project creation or when setting up another service that requires a location setting.

    If you're on the Blaze plan, you can create multiple buckets, each with its own location.

  4. Click Done.

Set up public access

Cloud Storage for Firebase provides a declarative rules language that allows you to define how your data should be structured, how it should be indexed, and when your data can be read from and written to. By default, read and write access to Storage is restricted so only authenticated users can read or write data. To get started without setting up Authentication, you can configure your rules for public access.

This does make Storage open to anyone, even people not using your app, so be sure to restrict your Storage again when you set up authentication.

Create and initialize firebase::App

Before you can access the Storage, you'll need to create and initialize the firebase::App.

Include the header file for firebase::App:

#include "firebase/app.h"

Android

Create the firebase::App, passing the JNI environment and a jobject reference to the Java Activity as arguments:

app = App::Create(AppOptions(), jni_env, activity);

iOS

Create the firebase::App:

app = App::Create(AppOptions());

Access the firebase::storage::Storage class

The firebase::storage::Storage class is the entry point for the Cloud Storage C++ SDK.

Storage* storage = Storage::GetInstance(app);

You're ready to start using Cloud Storage!

First, let's learn how to create a Cloud Storage reference.

Advanced setup

There are a few use cases that require additional setup:

The first use case is perfect if you have users across the world, and want to store their data near them. For instance, you can create buckets in the US, Europe, and Asia to store data for users in those regions to reduce latency.

The second use case is helpful if you have data with different access patterns. For instance: you can set up a multi-regional or regional bucket that stores pictures or other frequently accessed content, and a nearline or coldline bucket that stores user backups or other infrequently accessed content.

In either of these use cases, you'll want to use multiple storage buckets.

The third use case is useful if you're building an app, like Google Drive, which lets users have multiple logged in accounts (for instance, a personal account and a work account). You can use a custom Firebase App instance to authenticate each additional account.

Use multiple storage buckets

If you want to use a storage bucket other than the default provided above, or use multiple storage buckets in a single app, you can create an instance of firebase::storage::Storage that references your custom bucket:

// Get a non-default Storage bucket
Storage* storage = Storage::GetInstance("gs://my-custom-bucket");

Working with imported buckets

When importing an existing Cloud Storage bucket into Firebase, you'll have to grant Firebase the ability to access these files using the gsutil tool, included in the Google Cloud SDK:

gsutil -m acl ch -r -u firebase-storage@system.gserviceaccount.com:O gs://<your-cloud-storage-bucket>

This does not affect newly created buckets, as those have the default access control set to allow Firebase. This is a temporary measure, and will be performed automatically in the future.

Use a custom Firebase App

If you're building a more complicated app using a custom firebase::App, you can create an instance of firebase::storage::Storage initialized with that app:

// Get the default bucket from a custom firebase::App
Storage* storage = Storage::GetInstance(customApp);

// Get a non-default bucket from a custom firebase::App
Storage* storage = Storage::GetInstance(customApp, "gs://my-custom-bucket");

Next steps