How to get the default extension for a given content type?

Question

Given the variable content_type = "application/pdf" that can also include any other mime type.

How can I get the default extension for the content type?

I have currently two solutions, which seem very "complicated".

Hack the string

content_type.split("/")[1]

Use MIME::Types

  require 'mime/types'
  MIME::Types[content_type].first.extensions.first 

Is there a better solution?

Answer 1

All you need to is use ruby's Hash.invert method.

This answer shows how to do it:

Rack::Mime has this ability (and Rack is a dependency of Rails):

require 'rack/mime'
Rack::Mime::MIME_TYPES.invert['image/jpeg']  #=> ".jpg"

You may wish to memoize the inverted hash if you’re going to do the lookup often, as it’s not an inexpensive operation.

From your tags, it seems you are using rails anyway.