Setup

Google Service Account

In order to access a Firebase project using a server SDK, you must authenticate your requests to Firebase with Service Account credentials.

To authenticate a service account and authorize it to access Firebase services, you must generate a private key file in JSON format.

To generate a private key file for your service account:

  1. Open https://console.firebase.google.com/project/_/settings/serviceaccounts/adminsdk and select the project you want to generate a private key file for.
  2. Click Generate New Private Key, then confirm by clicking Generate Key
  3. Securely store the JSON file containing the key.

Note

You should store the JSON file outside of your code repository to avoid accidentally exposing it to the outside world.

You can then configure the SDK to use this Service Account:

With the SDK

use Kreait\Firebase\Factory;

$factory = (new Factory)->withServiceAccount('/path/to/firebase_credentials.json');

With the Symfony Bundle

Please see https://github.com/kreait/firebase-bundle#configuration

With the Laravel/Lumen Package

Please see https://github.com/kreait/laravel-firebase#configuration

With autodiscovery

The SDK is able to autodiscover the Service Account for your project in the following conditions:

  1. Your application runs on Google Cloud Engine.
  2. The path to the JSON key file is defined in one of the following environment variables
    • FIREBASE_CREDENTIALS
    • GOOGLE_APPLICATION_CREDENTIALS
  3. The JSON Key file is located in Google’s “well known path”
    • on Linux/MacOS: $HOME/.config/gcloud/application_default_credentials.json
    • on Windows: $APPDATA/gcloud/application_default_credentials.json

If you want to use autodiscovery, a Service Account must not be explicitly configured.

Custom Database URI

Note

It is not necessary to define a custom database URI in most cases.

If the project ID in the JSON file does not match the URL of your Firebase application, or if you want to be explicit, you can configure the Factory like this:

use Kreait\Firebase\Factory;

$factory = (new Factory())
    ->withDatabaseUri('https://my-project.firebaseio.com');

Caching

Authentication tokens

Before connecting to the Firebase APIs, the SDK fetches an authentication token for your credentials. This authentication token is cached in-memory so that it can be re-used during the same process.

If you want to cache authentication tokens more effectively, you can provide any implementation of psr/cache to the Firebase factory when creating your Firebase instance.

Note

Authentication tokens are cached in-memory by default. For Symfony and Laravel, the Framework’s cache will automatically be used.

For Symfony and Laravel, the Framework’s cache will automatically be used.

Here is an example using the Symfony Cache Component:

use Symfony\Component\Cache\Simple\FilesystemCache;

$factory = $factory->withAuthTokenCache(new FilesystemCache());

ID Token Verification

In order to verify ID tokens, the verifier makes a call to fetch Firebase’s currently available public keys. The keys are cached in memory by default.

If you want to cache the public keys more effectively, you can provide any implementation of psr/simple-cache to the Firebase factory when creating your Firebase instance.

Note

Public keys tokens are cached in-memory by default. For Symfony and Laravel, the Framework’s cache will automatically be used.

Here is an example using the Symfony Cache Component:

use Symfony\Component\Cache\Simple\FilesystemCache;

$factory = $factory->withVerifierCache(new FilesystemCache());

End User Credentials

Note

While theoretically possible, it’s not recommended to use end user credentials in the context of a Server-to-Server backend application.

When using End User Credentials (for example if you set you application default credentials locally with gcloud auth application-default login), you need to provide the ID of the project you want to access directly and suppress warnings triggered by the Google Auth Component:

use Kreait\Firebase\Factory;

putenv('SUPPRESS_GCLOUD_CREDS_WARNING=true');

// This will use the project defined in the Service Account
// credentials files by default
$base = (new Factory())->withProjectId('firebase-project-id');

HTTP Client Options

You can configure the behavior of the HTTP Client performing the API requests by passing an instance of KreaitFirebaseHttpHttpClientOptions to the factory before creating a service.

use Kreait\Firebase\Http\HttpClientOptions;

$options = HttpClientOptions::default();

// Set the maximum amount of seconds (float) that can pass before
// a request is considered timed out
// (default: indefinitely)
$options = $options->withTimeOut(3.5);

// Use a proxy that all API requests should be passed through.
// (default: none)
$options = $options->withProxy('tcp://<host>:<port>');

$factory = $factory->withHttpClientOptions($options);

// Newly created services will now use the new HTTP options
$realtimeDatabase = $factory->createDatabase();

Logging

In order to log API requests to the Firebase APIs, you can provide the factory with loggers implementing Psr\Log\LoggerInterface.

The following examples use the Monolog logger, but work with any PSR-3 log implementation.

use GuzzleHttp\MessageFormatter;
use Kreait\Firebase\Factory;
use Monolog\Logger;
use Monolog\Handler\StreamHandler;

$httpLogger = new Logger('firebase_http_logs');
$httpLogger->pushHandler(new StreamHandler('path/to/firebase_api.log', Logger::INFO));

// Without further arguments, requests and responses will be logged with basic
// request and response information. Successful responses will be logged with
// the 'info' log level, failures (Status code >= 400) with 'notice'
$factory = $factory->withHttpLogger($httpLogger);

// You can configure the message format and log levels individually
$messageFormatter = new MessageFormatter(MessageFormatter::SHORT);
$factory = $factory->withHttpLogger(
    $httpLogger, $messageFormatter, $successes = 'debug', $errors = 'warning'
);

// You can provide a separate logger for detailed HTTP message logs
$httpDebugLogger = new Logger('firebase_http_debug_logs');
$httpDebugLogger->pushHandler(
    new StreamHandler('path/to/firebase_api_debug.log',
    Logger::DEBUG)
);

// Logs will include the full request and response headers and bodies
$factory = $factory->withHttpDebugLogger($httpDebugLogger)