Question

I’m working on the file upload portion of a Rails app. Different types of files are handled differently by the app.

I want to make a whitelist of certain file extensions to check the uploaded files against to see where they should go. All of the file names are strings.

I need a way to check only the extension part of the file name string. The file names are all in the format of “some_file_name.some_extension”.

Answer 1

irb(main):002:0> accepted_formats = [".txt", ".pdf"]
=> [".txt", ".pdf"]
irb(main):003:0> File.extname("example.pdf") # get the extension
=> ".pdf"
irb(main):004:0> accepted_formats.include? File.extname("example.pdf")
=> true
irb(main):005:0> accepted_formats.include? File.extname("example.txt")
=> true
irb(main):006:0> accepted_formats.include? File.extname("example.png")
=> false