jClouds Java app to copy, move, delete files between Cloud services

Question

I am trying to implement a java multicloud web-application to copy, move, delete,... files from one cloud service (eg dropbox) to another cloud service (eg Google drive or OneDrive). The UI should show the user two panels: on the left, a panel with the source directory from cloud A and on the right panel the destination in cloud B to copy files to. The user should be able to choose the cloud service for source and destination with his own cloud-accounts.

I found the Apache jClouds project for cloud access with java and want to give it a try. I want to start with dropbox access...

1.) Are there any code examples/tutorials that show me how to start with jClouds and dropbox access?

2.) What are the correct provider and jCloud classes to connect with dropbox? I think dropbox uses amazon S3 web services. So, can I directly connect with dropbox or do I have to use amazon S3 as jCloud provider?

3.) I will implement a "WEB"-application. So what is the best solution to transfer files from one cloud service to the next? Should I transfer the files from cloud A to the webserver an upload it from here to cloud B? Or is there a direct way to transfer the files?

Thanx

Answer 1

1 and 2) Dropbox has its own API and does not expose S3. jclouds does not support the Dropbox API. You can find the Dropbox SDKs at:

https://www.dropbox.com/developers-v1/core

3) Generally you cannot interface one provider directly with another so you would need to download from one cloud then upload to another. Some providers like Azure allow copying a blob using a URL although Azure restricts the source to Azure and not external URLs. If you find a provider that does allow external URLs, consider creating signed URLs on the first cloud then using that URL as the source on the second cloud.