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require 'active_support/core_ext/object/blank'
module ActionDispatch
module Http
module Cache
module Request
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
def initialize(*)
status, header, body = super
@cache_control = {}
@etag = self["ETag"]
if cache_control = self["Cache-Control"]
cache_control.split(/,\s*/).each do |segment|
first, last = segment.split("=")
last ||= true
@cache_control[first.to_sym] = last
end
end
end
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 etag
@etag
end
def etag?
@etag
end
def etag=(etag)
key = ActiveSupport::Cache.expand_cache_key(etag)
@etag = self["ETag"] = %("#{Digest::MD5.hexdigest(key)}")
end
private
def handle_conditional_get!
if etag? || last_modified? || !@cache_control.empty?
set_conditional_cache_control!
elsif nonempty_ok_response?
self.etag = body
if request && request.etag_matches?(etag)
self.status = 304
self.body = []
end
set_conditional_cache_control!
else
headers["Cache-Control"] = "no-cache"
end
end
def nonempty_ok_response?
@status == 200 && string_body?
end
def string_body?
!@blank && @body.respond_to?(:all?) && @body.all? { |part| part.is_a?(String) }
end
DEFAULT_CACHE_CONTROL = "max-age=0, private, must-revalidate"
def set_conditional_cache_control!
return if self["Cache-Control"].present?
control = @cache_control
if control.empty?
headers["Cache-Control"] = DEFAULT_CACHE_CONTROL
elsif @cache_control[:no_cache]
headers["Cache-Control"] = "no-cache"
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
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