Google API authentication in Java without using environment variable

Question

I have set up a simple test app to interact with Google's Natural Language API. I created a service account, and downloaded the JSON credentials. I am running on a local development machine, so I set the GOOGLE_APPLICATION_CREDENTIALS environment variable to point to the JSON file. To be clear, this works: the app successfully makes some API calls and displays the results.

I would like to remove the dependence on the environment variable. How can I use the known location of the JSON file (or any other approach) in the application to create the LanguageServiceClient with those credentials?

Answer 1

You can register is like this:

DatastoreOptions options = DatastoreOptions.newBuilder()
  .setProjectId(PROJECT_ID)
  .setAuthCredentials(AuthCredentials.createForJson(
    new FileInputStream(PATH_TO_JSON_KEY))).build();

Does that help?

Answer 2

You can always pass the full json file as String as follows:

        CredentialsProvider credentialsProvider;
        String credentials = "[YOUR JSON FILE CONTENT]";

        try {

            credentialsProvider
                    = FixedCredentialsProvider.create(
                            ServiceAccountCredentials.fromStream(new ByteArrayInputStream(credentials.getBytes())));          

        } catch (IOException ex) {
            Logger.getLogger(GoogleNLPService.class.getName()).log(Level.SEVERE, null, ex);
        }

        LanguageServiceSettings.Builder languageServiceSettingsBuilder
                = LanguageServiceSettings.newBuilder();

        LanguageServiceSettings languageServiceSettings = languageServiceSettingsBuilder.setCredentialsProvider(credentialsProvider).build();

        List<NamedEntity> entities = new ArrayList<>();
        try (LanguageServiceClient language = LanguageServiceClient.create(languageServiceSettings)) {

         ...

        }

Alternatively, you can place your json file in resources folder and then read it as:

    credentialsProvider
            = FixedCredentialsProvider.create(
                    ServiceAccountCredentials.fromStream(new FileInputStream("./src/main/resources/FILENAME.json")));

However, this relative path didn't work when I uploaded my app in Heroku. So, I have decided to use the String solution.

Answer 3

We use a service account + GoogleCredential.Builder -- (note that this example uses a credential file in p12 format); example follows:

 private GoogleCredential authorize() throws IOException, GeneralSecurityException
{
    return new GoogleCredential.Builder()
    .setTransport(HTTP_TRANSPORT)
    .setJsonFactory(JSON_FACTORY)
    .setServiceAccountId(serviceAccount)
    .setServiceAccountScopes(SCOPES)
    .setServiceAccountUser(serviceAccountUser)
    // variable p12File is a String w/ path to the .p12 file name
    .setServiceAccountPrivateKeyFromP12File(new java.io.File(p12File))
      .build();
}