This middleware returns a file's contents from disk in the body response. When initialized it can accept an optional 'Cache-Control' header which will be set when a response containing a file's contents is delivered.

This middleware will render the file specified in `env` where the base path is in the root directory. For example if the root is set to `public/` then a request with `env` of `assets/application.js` will return a response with contents of a file located at `public/assets/application.js` if the file exists. If the file does not exist a 404 “File not Found” response will be returned.

Methods
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M
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Class Public methods
new(root, cache_control)

Source: show | on GitHub 

# File actionpack/lib/action_dispatch/middleware/static.rb, line 16
def initialize(root, cache_control)
  @root          = root.chomp('/')
  @compiled_root = /^#{Regexp.escape(root)}/
  headers        = cache_control && { 'Cache-Control' => cache_control }
  @file_server = ::Rack::File.new(@root, headers)
end
Instance Public methods
call(env)

Source: show | on GitHub 

# File actionpack/lib/action_dispatch/middleware/static.rb, line 44
def call(env)
  path      = env['PATH_INFO']
  gzip_path = gzip_file_path(path)

  if gzip_path && gzip_encoding_accepted?(env)
    env['PATH_INFO']            = gzip_path
    status, headers, body       = @file_server.call(env)
    if status == 304
      return [status, headers, body]
    end
    headers['Content-Encoding'] = 'gzip'
    headers['Content-Type']     = content_type(path)
  else
    status, headers, body = @file_server.call(env)
  end

  headers['Vary'] = 'Accept-Encoding' if gzip_path

  return [status, headers, body]
ensure
  env['PATH_INFO'] = path
end
match?(path)

Source: show | on GitHub 

# File actionpack/lib/action_dispatch/middleware/static.rb, line 23
def match?(path)
  path = URI.parser.unescape(path)
  return false unless valid_path?(path)

  paths = [path, "#{path}#{ext}", "#{path}/index#{ext}"].map { |v|
    Rack::Utils.clean_path_info v
  }

  if match = paths.detect { |p|
    path = File.join(@root, p.force_encoding('UTF-8'))
    begin
      File.file?(path) && File.readable?(path)
    rescue SystemCallError
      false
    end

  }
    return ::Rack::Utils.escape(match)
  end
end