Google Cloud Language V2 Setup

Getting Started with package:google_cloud_language_v2

1. Add the package to your pubspec.yaml

dart pub add google_cloud_language_v2

2. Import the library

In your Dart code, import the library:

import 'package:google_cloud_language_v2/language.dart';

3. Initialize the client

To call the client, you need to create an instance of the service that you want to use, e.g., LanguageService.

There are two ways of creating an instance with the necessary credentials.

Option A: Using Application Default Credentials (ADC) (Recommended)

Recommended for production environments, server-side backends, and when running on Google Cloud (such as Cloud Run, GCE, GKE).

When running on Google Cloud, Application Default Credentials are automatically available.

When running locally, the gcloud command must be available (see Install the Google Cloud CLI). To obtain Application Default Credentials, run:

gcloud auth application-default login

Add googleapis_auth to your dependencies:

dart pub add googleapis_auth

import 'package:googleapis_auth/auth_io.dart';
import 'package:google_cloud_language_v2/language.dart';

Future<void> main() async {
  final authClient = await clientViaApplicationDefaultCredentials(
    scopes: [
      'https://www.googleapis.com/auth/cloud-platform',
    ],
  );

  final client = LanguageService(client: authClient);

  try {
    // Call a method on the client.
    final response = await client.analyzeSentiment(
      AnalyzeSentimentRequest(),
    );
    print('Response: $response');
  } finally {
    // Always close the client to release resources.
    client.close();
  }
}

Option B: Using an API Key (Simple)

Recommended for quick testing or prototyping because the setup is simple.

If the user does not have an API key, then they can obtain one using the Google Cloud Console.

Add the API key to one of these environment variables:

• GOOGLE_API_KEY

import 'package:google_cloud_language_v2/language.dart';

Future<void> main() async {
  final client = LanguageService.fromApiKey();

  try {
    // Call a method on the client.
    final response = await client.analyzeSentiment(
      AnalyzeSentimentRequest(),
    );
    print('Response: $response');
  } finally {
    // Always close the client to release resources.
    client.close();
  }
}