Resumable upload in Drive Rest API V3

Question

I am trying to create a resumable upload session using drive rest API in Android.

As per the documentation the 3 steps needed to be followed are

1. Start

Answer 1

You don't have to care about all this logic. The documentation indeed explain the flow to complete a resumable upload but it's error prone if done "manually".
Fortunately, Google expose a dedicated class to handle such case, i.e the MediaHttpUploader.

This snippet of code do the job of a resumable upload on drive (same thing can be achieved on GCS):

public class Main {

private static final JacksonFactory JSON_FACTORY = new JacksonFactory();
private static final NetHttpTransport HTTP_TRANSPORT = new NetHttpTransport();
private static final MemoryDataStoreFactory DATA_STORE = new MemoryDataStoreFactory();

public static void main(String... args) throws IOException {


    Credential credential = authorize();

    MediaHttpUploader mediaHttpUploader = new MediaHttpUploader(new FileContent("application/json", Paths.get("/path/to/foo.json").toFile()), HTTP_TRANSPORT, credential);
    mediaHttpUploader.setProgressListener(uploader -> System.out.println("progress: " + uploader.getProgress()));
    GenericUrl genericUrl = new GenericUrl(new URL("https://www.googleapis.com/upload/drive/v3/files?name=toto"));
    GenericJson data = new GenericJson();
    data.put("name", "title");


    JsonHttpContent jsonHttpContent = new JsonHttpContent(JSON_FACTORY, data);
    mediaHttpUploader.setMetadata(jsonHttpContent).upload(genericUrl);

    System.out.println("Finished");
}

private static Credential authorize() throws IOException {
    // load client secrets
    try (BufferedReader br = Files.newBufferedReader(Paths.get(Resources.getResource("client_secret.json").getPath()))) {
        GoogleClientSecrets clientSecrets = GoogleClientSecrets.load(JSON_FACTORY, br);

        // set up authorization code flow
        GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(
                HTTP_TRANSPORT, JSON_FACTORY, clientSecrets,
                Collections.singleton(DriveScopes.DRIVE))
                .setAccessType("offline")
                .setDataStoreFactory(DATA_STORE).build();
        // authorize
        return new AuthorizationCodeInstalledApp(flow, new LocalServerReceiver()).authorize("user");

    }
}

}

Note that no where we mention location. All the logic is hidden in the MediaHttpUploader class.
So I don't really answer the question (where to find "Location") but I point the fact that this not really needed when using classes from Google library (and I am pretty sure other third party libraries exist to do the same job).

UPDATE: the mediaHttpUploader is what is used under the hood by the Drive v3 client. So we can think about something like that:

      File fileMetadata = new File();
    fileMetadata.setName(UPLOAD_FILE.getName());

    FileContent mediaContent = new FileContent("image/jpeg", UPLOAD_FILE);

    Drive.Files.Create insert = drive.files().create(fileMetadata, mediaContent);
    MediaHttpUploader uploader = insert.getMediaHttpUploader();
    uploader.setDirectUploadEnabled(false);
    uploader.setProgressListener(new FileUploadProgressListener());
    return insert.execute();