ModX Manager - Disabled Default Authentication and Write own Custom Authenticate .php scripts

Yes, this is fairly simple, though you'll still need to present a login form first (or use the MODX one).

You need a plugin that is connected to the OnManagerAuthentication System Event (and OnWebAuthentication if you need it in the front end).

Set $authenticated to true or false in your code and put this at the end of the plugin:

$modx->event->_output = (bool) $authenticated;
return; 

The true case will bypass the MODX authentication process and the user will be logged in. In the false case, the MODX authentication will proceed and will fail unless the user has entered their MODX credentials in the login form.

core/model/modx/processors/security/login.class.php

core/model/modx/modmanagerresponse.class.php

Sorry if I wasn't clear. You should *never* modify MODX core files. One of the great things about MODX is that you don't need to. You also rarely want to create .php files, since by default MODX keeps snippet and plugin code in the database.

If you create a plugin (on the Elements tree in the Manager), on the System Events tab, you'll see a list of all the System Events, including the ones I mentioned above. You just check the ones you want to attach the plugin to.

The code on this page is not up to date, but the explanation of how plugins work is still current.

$modx->event->output(true);

Try this:

$modx->event->_output = true;
return;

$modx->event->output(true);

$modx->event->_output = true;