> To save books in some place online like s3 or gdrive etc
How far did you make it with this? S3 is tricky because they don't offer OAuth so the user basically has to generate an IAM user and access keys and paste them into your app. I'm currently exploring solutions to this problem.
Right, I only got to that, I entered my s3 keys manually. I think for a smoother experience I would use Google Drive, which provides OAuth access AFAIK.
How far did you make it with this? S3 is tricky because they don't offer OAuth so the user basically has to generate an IAM user and access keys and paste them into your app. I'm currently exploring solutions to this problem.