Get user information Youtube v3 api after oauth

Question

I am trying to get the user email, that I used to log in with when performing Oauth2 through Youtube in my application. The code is similar to this:

        YouTube client = new YouTube.Builder(GoogleNetHttpTransport.newTrustedTransport(), JacksonFactory
            .getDefaultInstance(), credential)
            .setApplicationName("app_name").build();

        YouTube.Channels.List channelListByIdRequest = client.channels().list("snippet,contentDetails,statistics");
        channelListByIdRequest.setMine(true);
        ChannelListResponse channelListResponse = channelListByIdRequest.execute();

Here I pull the channel api, that, according to the doc is some kind of similar to the user api in v3. However, neither in Channel nor in any other API I cannot find how to get the email I logged in with. How can that information be accessed?

Answer 1

I have done some research and, unfortunately, there is indeed no possibility to fetch the email. As far as I understand, it is against the concept of Youtube and its data API - it deals with channels and multiple of those can be associated with a single email. Used this for reference: https://developers.google.com/youtube/v3/getting-started

However, you can use Google plus API scopes along with Youtube scopes to fetch the user info (but we need to take into account that it will be discarded by March 7, 2019)

     GoogleNetHttpTransport.newTrustedTransport(), JacksonFactory.getDefaultInstance(), clientSecrets,
    Arrays.asList(YouTubeScopes.YOUTUBE_FORCE_SSL, PlusScopes.PLUS_ME, PlusScopes.USERINFO_EMAIL))
    .setAccessType("offline").setApprovalPrompt("force").build();

We will be prompted to select email and channel in Oauth window and will be able to fetch the info.