I would like to customize a form base on the users' request info in a page callback. I use
node_add for node create form) to get the renderable array, but most changes to the array here have no effect.
I know that we usually use
hook_form_alter, but it seems not suit here.
I would like to hide/set a field, change a field's title/options etc. based on the query parameters or page arguments.
Do we have any methods to get the "raw describing form" and then modify and render it?