Map-interface and saving elements to spatial database

I need a map solution where user can draw/pull boxes in given sizes. The user has has to see the length and width value on screen in a dynamically way. Secondly, when the right size is chosen, the user shall be capable of rotating and placing the polygon. Finally the last step is to save it to spatial database were geojson as datatype are prefered and postGIS is a must have. If this can be done and integrated with Leaflet and maybe commbines with Leaflet Draw, then this is prefered. But another solution is possible if it works and you can show it. Regarding saving the drawn element to database: The script for connecting to database needs to be hidden and cannot be visible in index.html. I´ve got a working PostGIS-database that can be reached and tested with. If you handle this task well, then later projects might be send your way. I want the full code for reuse and self-learning. And if you´re english language skills are good, I´m interested in "from-time-to-time" communication if needed.