Hi employer,
I am good at Symfony based project, although I don't have much experience with barcode scanner. After some quick research, I know the scanner will deliver the number of the barcode as if it were typed on a keyboard, followed by a return. If you are using a form, barcode number will be filled in a pre-selected field (Part#) and submitted automatically when a barcode is scanned, Then, Symfony will handle the rest of thing as your description.
I realize your description start with 2 - PARTS. Is it the second part of your whole site. If yes, I will write this PARTS functionality in form of your existing code. If you expect it to be a standalone component separating from your existing code, I will package it as a standalone bundle and use REST API to complete read/write barcode, The benefit is you can regard it as a service and use it in anywhere, and build kinds of front barcode receiver and communicate with this service.
That is my basic idea about your project.
Just give me a message if you are interested in my opinion.
Kind Regards
Timefly