aboutsummaryrefslogtreecommitdiffstats
path: root/actionpack/lib/action_dispatch/middleware/static.rb
blob: 5c71f0fc48c35df43331476f6a042e48fb1e585b (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
require "rack/utils"
require "active_support/core_ext/uri"

module ActionDispatch
  # This middleware returns a file's contents from disk in the body response.
  # When initialized, it can accept optional HTTP headers, which will be set
  # when a response containing a file's contents is delivered.
  #
  # This middleware will render the file specified in `env["PATH_INFO"]`
  # where the base path is in the +root+ directory. For example, if the +root+
  # is set to `public/`, then a request with `env["PATH_INFO"]` of
  # `assets/application.js` will return a response with the 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.
  class FileHandler
    def initialize(root, index: "index", headers: {})
      @root          = root.chomp("/")
      @file_server   = ::Rack::File.new(@root, headers)
      @index         = index
    end

    # Takes a path to a file. If the file is found, has valid encoding, and has
    # correct read permissions, the return value is a URI-escaped string
    # representing the filename. Otherwise, false is returned.
    #
    # Used by the `Static` class to check the existence of a valid file
    # in the server's `public/` directory (see Static#call).
    def match?(path)
      path = ::Rack::Utils.unescape_path path
      return false unless ::Rack::Utils.valid_path? path
      path = ::Rack::Utils.clean_path_info path

      paths = [path, "#{path}#{ext}", "#{path}/#{@index}#{ext}"]

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

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

    def call(env)
      serve(Rack::Request.new(env))
    end

    def serve(request)
      path      = request.path_info
      gzip_path = gzip_file_path(path)

      if gzip_path && gzip_encoding_accepted?(request)
        request.path_info           = gzip_path
        status, headers, body       = @file_server.call(request.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(request.env)
      end

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

      return [status, headers, body]
    ensure
      request.path_info = path
    end

    private
      def ext
        ::ActionController::Base.default_static_extension
      end

      def content_type(path)
        ::Rack::Mime.mime_type(::File.extname(path), "text/plain".freeze)
      end

      def gzip_encoding_accepted?(request)
        request.accept_encoding.any? { |enc, quality| enc =~ /\bgzip\b/i }
      end

      def gzip_file_path(path)
        can_gzip_mime = content_type(path) =~ /\A(?:text\/|application\/javascript)/
        gzip_path     = "#{path}.gz"
        if can_gzip_mime && File.exist?(File.join(@root, ::Rack::Utils.unescape_path(gzip_path)))
          gzip_path
        else
          false
        end
      end
  end

  # This middleware will attempt to return the contents of a file's body from
  # disk in the response. If a file is not found on disk, the request will be
  # delegated to the application stack. This middleware is commonly initialized
  # to serve assets from a server's `public/` directory.
  #
  # This middleware verifies the path to ensure that only files
  # living in the root directory can be rendered. A request cannot
  # produce a directory traversal using this middleware. Only 'GET' and 'HEAD'
  # requests will result in a file being returned.
  class Static
    def initialize(app, path, index: "index", headers: {})
      @app = app
      @file_handler = FileHandler.new(path, index: index, headers: headers)
    end

    def call(env)
      req = Rack::Request.new env

      if req.get? || req.head?
        path = req.path_info.chomp("/".freeze)
        if match = @file_handler.match?(path)
          req.path_info = match
          return @file_handler.serve(req)
        end
      end

      @app.call(req.env)
    end
  end
end