trailofbits/http-security

require 'http/security/parsers/parser'

module HTTP
  module Security
    module Parsers
      class CacheControl < Parser
        # Cache-Control
        # Syntax:
        # Cache-Control   = "Cache-Control" ":" 1#cache-directive
        # cache-directive = cache-response-directive
        #  cache-response-directive =
        #        "public"                               ; Section 14.9.1
        #      | "private" [ "=" <"> 1#field-name <"> ] ; Section 14.9.1
        #      | "no-cache" [ "=" <"> 1#field-name <"> ]; Section 14.9.1
        #      | "no-store"                             ; Section 14.9.2
        #      | "no-transform"                         ; Section 14.9.5
        #      | "must-revalidate"                      ; Section 14.9.4
        #      | "proxy-revalidate"                     ; Section 14.9.4
        #      | "max-age" "=" delta-seconds            ; Section 14.9.3
        #      | "s-maxage" "=" delta-seconds           ; Section 14.9.3
        #      | cache-extension                        ; Section 14.9.6
        # cache-extension = token [ "=" ( token | quoted-string ) ]
        rule(:cache_control) do
          (
            cache_control_values >> (comma >> cache_control_values).repeat
          ).as(:directives)
        end
        root :cache_control

        rule(:cache_control_values) do
            cc_public       |
            cc_private      |
            no_cache        |
            no_store        |
            no_transform    |
            must_revalidate |
            max_age         |
            s_maxage        |
            only_if_cached  |
            header_extension
        end

        #"private" [ "=" <"> 1#field-name <"> ];
        rule(:cc_public) do
          stri("public").as(:key) >> (equals >> field_name.as(:value)).maybe
        end

        #"private" [ "=" <"> 1#field-name <"> ];
        rule(:cc_private) do
          stri("private").as(:key) >> (equals >> field_name.as(:value)).maybe
        end

        field_directive_rule :no_cache, 'no-cache'
        directive_rule :no_store, 'no-store'
        directive_rule :no_transform, 'no-transform'
        directive_rule :must_revalidate, 'must-revalidate'
        directive_rule :only_if_cached, 'only-if-cached'

      end
    end
  end
end