require 'active_support/core_ext/object/blank' module ActionDispatch module Http module Cache module Request HTTP_IF_MODIFIED_SINCE = 'HTTP_IF_MODIFIED_SINCE'.freeze HTTP_IF_NONE_MATCH = 'HTTP_IF_NONE_MATCH'.freeze def if_modified_since if since = env[HTTP_IF_MODIFIED_SINCE] Time.rfc2822(since) rescue nil end end def if_none_match env[HTTP_IF_NONE_MATCH] end def not_modified?(modified_at) if_modified_since && modified_at && if_modified_since >= modified_at end def etag_matches?(etag) if_none_match && if_none_match == etag end # Check response freshness (Last-Modified and ETag) against request # If-Modified-Since and If-None-Match conditions. If both headers are # supplied, both must match, or the request is not considered fresh. def fresh?(response) last_modified = if_modified_since etag = if_none_match return false unless last_modified || etag success = true success &&= not_modified?(response.last_modified) if last_modified success &&= etag_matches?(response.etag) if etag success end end module Response attr_reader :cache_control, :etag alias :etag? :etag def last_modified if last = headers[LAST_MODIFIED] Time.httpdate(last) end end def last_modified? headers.include?(LAST_MODIFIED) end def last_modified=(utc_time) headers[LAST_MODIFIED] = utc_time.httpdate end def date if date_header = headers['Date'] Time.httpdate(date_header) end end def date? headers.include?('Date') end def date=(utc_time) headers['Date'] = utc_time.httpdate end def etag=(etag) key = ActiveSupport::Cache.expand_cache_key(etag) @etag = self[ETAG] = %("#{Digest::MD5.hexdigest(key)}") end private LAST_MODIFIED = "Last-Modified".freeze ETAG = "ETag".freeze CACHE_CONTROL = "Cache-Control".freeze SPESHUL_KEYS = %w[extras no-cache max-age public must-revalidate] def cache_control_headers cache_control = {} if cc = self[CACHE_CONTROL] cc.delete(' ').split(',').each do |segment| directive, argument = segment.split('=', 2) case directive when *SPESHUL_KEYS key = directive.tr('-', '_') cache_control[key.to_sym] = argument || true else cache_control[:extras] ||= [] cache_control[:extras] << segment end end end cache_control end def prepare_cache_control! @cache_control = cache_control_headers @etag = self[ETAG] end def handle_conditional_get! if etag? || last_modified? || !@cache_control.empty? set_conditional_cache_control! end end DEFAULT_CACHE_CONTROL = "max-age=0, private, must-revalidate".freeze NO_CACHE = "no-cache".freeze PUBLIC = "public".freeze PRIVATE = "private".freeze MUST_REVALIDATE = "must-revalidate".freeze def set_conditional_cache_control! control = {} cc_headers = cache_control_headers if extras = cc_headers.delete(:extras) @cache_control[:extras] ||= [] @cache_control[:extras] += extras @cache_control[:extras].uniq! end control.merge! cc_headers control.merge! @cache_control if control.empty? headers[CACHE_CONTROL] = DEFAULT_CACHE_CONTROL elsif control[:no_cache] headers[CACHE_CONTROL] = NO_CACHE if control[:extras] headers[CACHE_CONTROL] += ", #{control[:extras].join(', ')}" end else extras = control[:extras] max_age = control[:max_age] options = [] options << "max-age=#{max_age.to_i}" if max_age options << (control[:public] ? PUBLIC : PRIVATE) options << MUST_REVALIDATE if control[:must_revalidate] options.concat(extras) if extras headers[CACHE_CONTROL] = options.join(", ") end end end end end end