Enable Authentication for SSO Users

[bxbrenden]

TL;DR

Please consider adding support for SSO users that do not have a password

Background

The way the downloader works currently relies upon both a username and a password to authenticate. This makes sense, but not all users that have a paid account use a password. In my case, my company has Oreilly linked to their Single-Sign-On server. As soon as I enter my email address, the password input field is hidden, and a button appears that redirects me to my company's SSO server. Once I authenticate, I am returned to Oreilly and can access books.

Feature Request

It would be great if the README.md file explained how to retrieve the Bearer Authorization Token manually from browser developer tools or HTTP responses and if SafariBooks-Downloader allowed you to enter that as a password or token in the command-line arguments. Something along the lines of:

safaribooks-downloader -b 9781484224427 -u nicohaenggi --token <Bearer_Auth_Token> -o /Users/nicohanggi/Desktop/testbook.epub