Access google photos API via Java

Question

I am very new to google API and I am having troubles with it. I red documentation Google photos API for Java , then I created OAuth credentials in google API console and downloaded it (credentials.json file). After that I tried to access google photos. Here is code from documentation:

// Set up the Photos Library Client that interacts with the API
PhotosLibrarySettings settings =
   PhotosLibrarySettings.newBuilder()
  .setCredentialsProvider(
      FixedCredentialsProvider.create(/* Add credentials here. */)) 
  .build();

try (PhotosLibraryClient photosLibraryClient =
    PhotosLibraryClient.initialize(settings)) {

  // Create a new Album  with at title
  Album createdAlbum = photosLibraryClient.createAlbum("My Album");

  // Get some properties from the album, such as its ID and product URL
  String id = album.getId();
  String url = album.getProductUrl();

 } catch (ApiException e) {
    // Error during album creation
 }

But I don't understand how to create Credentials object to pass it to the FixedCredentialsProvider.create() method

Could you please provide me with some explanation/links about it?

Answer 1

You can create a UserCredentials Object and pass it

UserCredentials.newBuilder()
        .setClientId("your client id")
        .setClientSecret("your client secret")
        .setAccessToken("Access Token")
        .build()

Go through this answer https://stackoverflow.com/a/54533855/6153171

Or check out this complete project on github https://github.com/erickogi/AndroidGooglePhotosApi

Answer 2

The FixedCredentialsProvider.create(..) call takes in a com.google.auth.Credentials object . For the Google Photos Library API, this should be a UserCredentials object, that you can create UserCredentials.Builder that is part of the Google OAuth library . There you set the refresh token, client ID, client secret, etc. to initialise the credentials. Getting a refresh token requires your app to complete the GoogleAuthorizationCodeFlow that prompts the user for authorization and approval.

You can check out the sample implementation on GitHub , but this is the relevant code:

GoogleAuthorizationCodeFlow flow =
        new GoogleAuthorizationCodeFlow.Builder(
                GoogleNetHttpTransport.newTrustedTransport(),
                JSON_FACTORY,
                clientSecrets,
                selectedScopes)
            .setDataStoreFactory(new FileDataStoreFactory(DATA_STORE_DIR))
            .setAccessType("offline")
            .build();
    LocalServerReceiver receiver =
        new LocalServerReceiver.Builder().setPort(LOCAL_RECEIVER_PORT).build();
    Credential credential = new AuthorizationCodeInstalledApp(flow, receiver).authorize("user");
    return UserCredentials.newBuilder()
        .setClientId(clientId)
        .setClientSecret(clientSecret)
        .setRefreshToken(credential.getRefreshToken())
        .build();

There are a few moving parts involved, but the Google Photos Library API client library works with the Google Authentication library to handle OAuth authentication.

Answer 3

You need to understand about OAuth 2 first: https://www.digitalocean.com/community/tutorials/an-introduction-to-oauth-2

Then you can look this answer https://stackoverflow.com/a/54533855/6153171

P/s: 1. Grant Type: Authorization Code Google developer console : credential is web client.

GoogleApiClient -> addScope, requestServerCode -> grand permission -> get account -> getServerAuthenCode -> get AccessToken ( https://stackoverflow.com/a/54533855/6153171 ) -> I tested and it works well. You can follow this way

2. Grant Type: Implicit Google developer console : credential is android or ios app.

GoogleApiClient -> addScope, requestTokenID -> grand permission -> get account -> getTokenID -> get AccessToken. I didn't try successfully to grant authorization for google photo api. But with firebase authentication, we can use this way because firebase support class util for us.