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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 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
def prepare_cache_control!
@cache_control = {}
@etag = self[ETAG]
if cache_control = self[CACHE_CONTROL]
cache_control.split(/,\s*/).each do |segment|
first, last = segment.split("=")
@cache_control[first.to_sym] = last || true
end
end
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!
return if self[CACHE_CONTROL].present?
control = @cache_control
if control.empty?
headers[CACHE_CONTROL] = DEFAULT_CACHE_CONTROL
elsif 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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