A generic swappable back-end for MIME type detection

Lots of ruby libraries utilize MIME type detection in some form. In order to best support multiple MIME type detection libraries, multi_mime is a general-purpose, swappable, MIME type detection backend library.

eg MultiJson for MIME types.

gem 'multi_mime', '~> 1.1'

require 'multi_mime'

Part of utilizing various MIME type libraries is the need for a common interface. MultiMime provides just that with following methods.

MultiMime.type_for('text/html') # 'text/html'
# alias :by_type

MultiMime.type_for_extension('.html') # 'text/html'
# alias :by_extension

MultiMime.type_for_path('/usr/local/foo/bar/foo.html') # 'text/html'
# alias :by_path

MultiMime.type_for_file(File.open('foo.html', 'w')) # 'text/html'
# alias :by_file

MultiMime tries to have intelligent defaulting. That is, if you have any of the supported engines already loaded, it will utilize them before attempting to load any. When loading, libraries are ordered in the same order as Supported Mime Engines. Lets try using MultiMime with Rack::Mime loaded, then switch it to MIME::Types.

require 'rack/mime' # true

MultiMime.default_adapter # ':rack_mime'

MultiMime.adapter # MultiMime::Adapters::RackMime

MultiMime.reset_adapter # MultiMime::Adapters::RackMime

MultiMime.adapter = :mime_types # `:mime_types`

require 'mime/types' # false (eg loaded)

MultiMime.adapter # MultiMime::Adapters::MimeTypes

MultiMime.type_for_extension('.json') # 'application/json'

When MultiMime fails to load the specified adapter, it'll throw MultiMime::AdapterError which inherits from ArgumentError.

• MIME::Types
• MagicMime
• Rails (ActionDispatch::Http::Mime)
• Rack (Rack::Mime)

This library aims to support and is tested against the following Ruby implementations:

• Ruby 2.3.0
• Ruby 2.2.0
• Ruby 2.1.0
• Ruby 2.0.0
• Ruby 1.9.3
• JRuby
• Rubinius

Inspiration:

• MultiJSON
• MultiXML

Cribbed:

• MultiJSON
• Asset_Sync's MultiMime module