Re: oauth2 support for Emacs email clients

["Roland Winkler" <winkler@gnu.org>]

On Wed, Aug 11 2021, Richard Stallman wrote:
> > > Is DevMail free software?  Does it implement that protocol with
> > > free software?
>
> > GPL (http://davmail.sourceforge.net/licenses.html).
>
> That's good.  (Which GPL versions does it allow?)

davmail is GPL version 2 (no later version).

> So, what part of the problem does DevMail solve?
> Which cases is it usable in?

It is a local gateway for Microsoft Exchange / Office365 so that a local
IMAP / SMTP client such as gnus can communicate with the server.  For
this, davmail performs the OAuth2 authentication and authorization with
the Microsoft server.

davmail supports only Microsoft Exchange / Office365.  Other systems
such as gmail are not supported.

> What part of the problem remains to be solved?

I just confirmed: the Microsoft server requires that javascript is
enabled in the browser.  When I disable javascript in my firefox
browser, it gives me the error message:

  Microsoft
  We can't sign you in
  JavaScript is required to sign in. Your browser either
  does not support JavaScript or it is being blocked.
  Enable JavaScript in your browser or use one which supports it.

  See https://login.microsoftonline.com/jsdisabled

In oauth2.el, this problem is hidden in oauth2-request-authorization,
where browse-url delegates the actual OAuth2 authentication to an
(external) browser.  If oauth2.el is used with Microsoft Exchange /
Office365, it only works with a browser that supports javascript.

(I not know about the implementation of OAuth2 for other systems such as
Gmail.)