How to load and download the data from a remote directory in flutter?

Question

I have a directory full of pdf's with name as A00-2020-01.pdf
The A00 is the user ID, 2020 is year, 01 is month
And the directory is full of 1800 members with 1800 id's The pdf's are bills, so pdf's are made every month hence the reason 01 January month. I am using getstorage() for user ID But how should I send the year and month to fetch the pdf and render it on phone Aim is, for ex.. Member A00 can only see his pdf. Should I send the year and month in json? As the member is already logged in the userid is already in getstorage().

Please guys I need help on this..