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cache_control.rb
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cache_control.rb
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# frozen_string_literal: true
module Faraday
class HttpCache < Faraday::Middleware
# Internal: A class to represent the 'Cache-Control' header options.
# This implementation is based on 'rack-cache' internals by Ryan Tomayko.
# It breaks the several directives into keys/values and stores them into
# a Hash.
class CacheControl
# Internal: Initialize a new CacheControl.
def initialize(header)
@directives = parse(header.to_s)
end
# Internal: Checks if the 'public' directive is present.
def public?
@directives['public']
end
# Internal: Checks if the 'private' directive is present.
def private?
@directives['private']
end
# Internal: Checks if the 'no-cache' directive is present.
def no_cache?
@directives['no-cache']
end
# Internal: Checks if the 'no-store' directive is present.
def no_store?
@directives['no-store']
end
# Internal: Gets the 'max-age' directive as an Integer.
#
# Returns nil if the 'max-age' directive isn't present.
def max_age
@directives['max-age'].to_i if @directives.key?('max-age')
end
# Internal: Gets the 'max-age' directive as an Integer.
#
# takes the age header integer value and reduces the max-age and s-maxage
# if present to account for having to remove static age header when caching responses
def normalize_max_ages(age)
if age > 0
@directives['max-age'] = @directives['max-age'].to_i - age if @directives.key?('max-age')
@directives['s-maxage'] = @directives['s-maxage'].to_i - age if @directives.key?('s-maxage')
end
end
# Internal: Gets the 's-maxage' directive as an Integer.
#
# Returns nil if the 's-maxage' directive isn't present.
def shared_max_age
@directives['s-maxage'].to_i if @directives.key?('s-maxage')
end
alias s_maxage shared_max_age
# Internal: Checks if the 'must-revalidate' directive is present.
def must_revalidate?
@directives['must-revalidate']
end
# Internal: Checks if the 'proxy-revalidate' directive is present.
def proxy_revalidate?
@directives['proxy-revalidate']
end
# Internal: Gets the String representation for the cache directives.
# Directives are joined by a '=' and then combined into a single String
# separated by commas. Directives with a 'true' value will omit the '='
# sign and their value.
#
# Returns the Cache Control string.
def to_s
booleans = []
values = []
@directives.each do |key, value|
if value == true
booleans << key
elsif value
values << "#{key}=#{value}"
end
end
(booleans.sort + values.sort).join(', ')
end
private
# Internal: Parses the Cache Control string to a Hash.
# Existing whitespace will be removed and the string is split on commas.
# For each part everything before a '=' will be treated as the key
# and the exceeding will be treated as the value. If only the key is
# present then the assigned value will default to true.
#
# Examples:
# parse("max-age=600")
# # => { "max-age" => "600"}
#
# parse("max-age")
# # => { "max-age" => true }
#
# Returns a Hash.
def parse(header)
directives = {}
header.delete(' ').split(',').each do |part|
next if part.empty?
name, value = part.split('=', 2)
directives[name.downcase] = (value || true) unless name.empty?
end
directives
end
end
end
end