Is it better to use threads or fork in the following case

[grocery_stocker]

Let's say there is a new zip file with updated information every 30
minutes on a remote website. Now, I wanna connect to this website
every 30 minutes, download the file, extract the information, and then
have the program search the file search for certain items.

Would it be better to use threads to break this up? I have one thread
download the data and then have another to actually process the data .
Or would it be better to use fork?