Hello! Dropbox. I was in trouble time ago, blocked by a big health problem: in this time i had start a dropbox plugin for WP, after interrupted due to a surgery to resolve the big health problem. So i've re-start my activity on PC in full, after long time. I've so re-look to the old test, and i've been noticed that API2 was released.
You say right about json, just calls to api url can change maybe, and some endpoint, and some array results. In true i was using a very old php code provided as example, based on API1, where also php code was obsolete in true. The original one, and all what i had add.
i've restart one completely from scratch, it is almost ready and provide on WP:
files manager, on each front-end dbx user page for shared links: display, upload, unlink, delete, create folder features.
files images on front end, if clicked on folder, fire jquery images gallery in WP.
Ready to add any other option/feature about teams, members etc.
Adding some WP features:
Admin can choose if all users can use/access this feature, or just some group or particular username.
how many file to retrieve and display option.
how breadcrumb and shared files need to display.
cache to avoid curl calls when not necessary.
And all the rest, mixing WP and dbx API features, provided on request or when the plugin will be improved along the time.
The online example will be very soon available at:
https://www.w3tasks.com
Will not be a free plugin.
But a free version will be also provided for the WP repo.