My question is complicated, I'm sorry about it :) Please, could I ask for help and advice ? :)
Take a dedicated server (meaning : total mysql/scripting freedom, a debian + webmin + virtualmin, if the information matters), holding two domains, one with a WordPress blog, and the other domain with another-than-wordpress CMS, with a database, and in its in database, among other elements, "username" and "password" fields.
I would like to synchronize, on a regular basis (for instance once per day, but cron configuration is not today's topic), the username:password fields of that database with the Users and users_meta fields of the WordPress database .
So that for every username:password entry of that other-than-wordpress database, a wordpress user is created (if not already existing) with the same login and password.
The rank of those wordpress users would be the lowest default rank, Subscriber.
The idea behind this : registration to that blog would not be permitted, being a member would be a privilege coming with members-only advantages (for instance the "no adverts for friends" plugin, to give you an idea). And that privilege would come from being a member in another website. Making the process automated would allow to keep the same credentials, and to save human work time.
Straight instructions to ask to insert rows if the username doesn't exist yet, with the password, and the default Subscriber options, wouldn't work, since the passwords are not stored in clear in the WordPress DB, and I have no idea how they're mashed/minchd/whatever-you-call-it.
(Even assuming that the passwords would be stored in clear in the other CMS's database, I'll leave that point aside, it's not wordpress-relevant.)
And, to be honest, I haven't worked yet on a php script handling two databases at once, I suppose it can be done - I'm just saying this is still alien to me at the moment we speak.
I hope I'm not asking for the impossible, do you know if it is doable ?
If there are ways to achieve that result ?
Thank you VERY MUCH if you can help, I'll be grateful :)