Install an ejabberd with synchronized credentials

Ejabberd is a chat server that uses XMPP as messaging protocol that you can use with a large amount of clients. In conjunction with the "xmpp" addon it can be used for a web based chat solution for your users. Installation

Change it's owner to whichever user is running the server, ie. ejabberd

$ chown ejabberd:ejabberd /path/to/friendica/include/auth_ejabberd.php

Change the access mode so it is readable only to the user ejabberd and has exec

$ chmod 700 /path/to/friendica/include/auth_ejabberd.php

Edit your ejabberd.cfg file, comment out your auth_method and add:

{auth_method, external}.
{extauth_program, "/path/to/friendica/include/auth_ejabberd.php"}.

Disable the module "mod_register" and disable the registration:

{access, register, [{deny, all}]}.

Enable BOSH:
    Enable the module "mod_http_bind"

    Edit this line:

    {5280, ejabberd_http, [captcha, http_poll, http_bind]}

    In your apache configuration for your site add this line:

    ProxyPass /http-bind http://127.0.0.1:5280/http-bind retry=0

Restart your ejabberd service, you should be able to login with your friendica credentials

Other hints

if a user has a space or a @ in the nickname, the user has to replace these characters:
    " " (space) is replaced with "%20"
    "@" is replaced with "(a)"