# class Rack::Static

The `Rack::Static` middleware intercepts requests for static files (javascript files, images, stylesheets, etc) based on the url prefixes or route mappings passed in the options, and serves them using a `Rack::Files` object. This allows a `Rack` stack to serve both static and dynamic content.

Examples:

Serve all requests beginning with /media from the “media” folder located in the current directory (ie media/*):

    use Rack::Static, :urls => ["/media"]

Same as previous, but instead of returning 404 for missing files under /media, call the next middleware:

    use Rack::Static, :urls => ["/media"], :cascade => true

Serve all requests beginning with /css or /images from the folder “public” in the current directory (ie public/css/* and public/images/*):

    use Rack::Static, :urls => ["/css", "/images"], :root => "public"

Serve all requests to / with “index.html” from the folder “public” in the current directory (ie public/index.html):

    use Rack::Static, :urls => {"/" => 'index.html'}, :root => 'public'

Serve all requests normally from the folder “public” in the current directory but uses index.html as default route for “/”

    use Rack::Static, :urls => [""], :root => 'public', :index =>
    'index.html'

Set custom HTTP Headers for based on rules:

       use Rack::Static, :root => 'public',
           :header_rules => [
             [rule, {header_field => content, header_field => content}],
             [rule, {header_field => content}]
           ]

    Rules for selecting files:

    1) All files
       Provide the :all symbol
       :all => Matches every file

    2) Folders
       Provide the folder path as a string
       '/folder' or '/folder/subfolder' => Matches files in a certain folder

    3) File Extensions
       Provide the file extensions as an array
       ['css', 'js'] or %w(css js) => Matches files ending in .css or .js

    4) Regular Expressions / Regexp
       Provide a regular expression
       %r{\.(?:css|js)\z} => Matches files ending in .css or .js
       /\.(?:eot|ttf|otf|woff2|woff|svg)\z/ => Matches files ending in
         the most common web font formats (.eot, .ttf, .otf, .woff2, .woff, .svg)
         Note: This Regexp is available as a shortcut, using the :fonts rule

    5) Font Shortcut
       Provide the :fonts symbol
       :fonts => Uses the Regexp rule stated right above to match all common web font endings

    Rule Ordering:
      Rules are applied in the order that they are provided.
      List rather general rules above special ones.

    Complete example use case including HTTP header rules:

       use Rack::Static, :root => 'public',
           :header_rules => [
             # Cache all static files in public caches (e.g. Rack::Cache)
             #  as well as in the browser
             [:all, {'Cache-Control' => 'public, max-age=31536000'}],

             # Provide web fonts with cross-origin access-control-headers
             #  Firefox requires this when serving assets using a Content Delivery Network
             [:fonts, {'Access-Control-Allow-Origin' => '*'}]
           ]

### Public Class Methods

new(app, options = {}) click to toggle source

    # File lib/rack/static.rb, line 91
    def initialize(app, options = {})
      @app = app
      @urls = options[:urls] || ["/favicon.ico"]
      if @urls.kind_of?(Array)
        @urls = @urls.map { |url| [url, url.end_with?('/') ? url : "#{url}/".freeze].freeze }.freeze
      end
      @index = options[:index]
      @gzip = options[:gzip]
      @cascade = options[:cascade]
      root = options[:root] || Dir.pwd

      # HTTP Headers
      @header_rules = options[:header_rules] || []
      # Allow for legacy :cache_control option while prioritizing global header_rules setting
      @header_rules.unshift([:all, { CACHE_CONTROL => options[:cache_control] }]) if options[:cache_control]

      @file_server = Rack::Files.new(root)
    end

### Public Instance Methods

add_index_root?(path) click to toggle source

    # File lib/rack/static.rb, line 110
    def add_index_root?(path)
      @index && route_file(path) && path.end_with?('/')
    end

applicable_rules(path) click to toggle source

Convert HTTP header rules to HTTP headers

    # File lib/rack/static.rb, line 170
    def applicable_rules(path)
      path = ::Rack::Utils.unescape_path(path)

      @header_rules.find_all do |rule, new_headers|
        case rule
        when :all
          true
        when :fonts
          /\.(?:ttf|otf|eot|woff2|woff|svg)\z/.match?(path)
        when String
          path.start_with?(rule) || path.start_with?('/' + rule)
        when Array
          /\.#{Regexp.union(rule)}\z/.match?(path)
        when Regexp
          rule.match?(path)
        else
          false
        end
      end
    end

call(env) click to toggle source

    # File lib/rack/static.rb, line 126
    def call(env)
      path = env[PATH_INFO]
      actual_path = Utils.clean_path_info(Utils.unescape_path(path))

      if can_serve(actual_path)
        if overwrite_file_path(path)
          env[PATH_INFO] = (add_index_root?(path) ? path + @index : @urls[path])
        elsif @gzip && env['HTTP_ACCEPT_ENCODING'] && /\bgzip\b/.match?(env['HTTP_ACCEPT_ENCODING'])
          path = env[PATH_INFO]
          env[PATH_INFO] += '.gz'
          response = @file_server.call(env)
          env[PATH_INFO] = path

          if response[0] == 404
            response = nil
          elsif response[0] == 304
            # Do nothing, leave headers as is
          else
            if mime_type = Mime.mime_type(::File.extname(path), 'text/plain')
              response[1][CONTENT_TYPE] = mime_type
            end
            response[1]['Content-Encoding'] = 'gzip'
          end
        end

        path = env[PATH_INFO]
        response ||= @file_server.call(env)

        if @cascade && response[0] == 404
          return @app.call(env)
        end

        headers = response[1]
        applicable_rules(path).each do |rule, new_headers|
          new_headers.each { |field, content| headers[field] = content }
        end

        response
      else
        @app.call(env)
      end
    end

can_serve(path) click to toggle source

    # File lib/rack/static.rb, line 122
    def can_serve(path)
      route_file(path) || overwrite_file_path(path)
    end

overwrite_file_path(path) click to toggle source

    # File lib/rack/static.rb, line 114
    def overwrite_file_path(path)
      @urls.kind_of?(Hash) && @urls.key?(path) || add_index_root?(path)
    end

route_file(path) click to toggle source

    # File lib/rack/static.rb, line 118
    def route_file(path)
      @urls.kind_of?(Array) && @urls.any? { |url, url_slash| path == url || path.start_with?(url_slash) }
    end