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# frozen_string_literal: true
# Released under the MIT License.
# Copyright, 2020-2025, by Samuel Williams.
# Copyright, 2023, by Thomas Morgan.
require_relative "split"
module Protocol
module HTTP
module Header
# Represents the `cache-control` header, which is a list of cache directives.
class CacheControl < Split
# The `private` directive indicates that the response is intended for a single user and must not be stored by shared caches.
PRIVATE = "private"
# The `public` directive indicates that the response may be stored by any cache, even if it would normally be considered non-cacheable.
PUBLIC = "public"
# The `no-cache` directive indicates that caches must revalidate the response with the origin server before serving it to clients.
NO_CACHE = "no-cache"
# The `no-store` directive indicates that caches must not store the response under any circumstances.
NO_STORE = "no-store"
# The `max-age` directive indicates the maximum amount of time, in seconds, that a response is considered fresh.
MAX_AGE = "max-age"
# The `s-maxage` directive is similar to `max-age` but applies only to shared caches. If both `s-maxage` and `max-age` are present, `s-maxage` takes precedence in shared caches.
S_MAXAGE = "s-maxage"
# The `static` directive is a custom directive often used to indicate that the resource is immutable or rarely changes, allowing longer caching periods.
STATIC = "static"
# The `dynamic` directive is a custom directive used to indicate that the resource is generated dynamically and may change frequently, requiring shorter caching periods.
DYNAMIC = "dynamic"
# The `streaming` directive is a custom directive used to indicate that the resource is intended for progressive or chunked delivery, such as live video streams.
STREAMING = "streaming"
# The `must-revalidate` directive indicates that once a response becomes stale, caches must not use it to satisfy subsequent requests without revalidating it with the origin server.
MUST_REVALIDATE = "must-revalidate"
# The `proxy-revalidate` directive is similar to `must-revalidate` but applies only to shared caches.
PROXY_REVALIDATE = "proxy-revalidate"
# Initializes the cache control header with the given value. The value is expected to be a comma-separated string of cache directives.
#
# @parameter value [String | Nil] the raw Cache-Control header value.
def initialize(value = nil)
super(value&.downcase)
end
# Adds a directive to the Cache-Control header. The value will be normalized to lowercase before being added.
#
# @parameter value [String] the directive to add.
def << value
super(value.downcase)
end
# @returns [Boolean] whether the `static` directive is present.
def static?
self.include?(STATIC)
end
# @returns [Boolean] whether the `dynamic` directive is present.
def dynamic?
self.include?(DYNAMIC)
end
# @returns [Boolean] whether the `streaming` directive is present.
def streaming?
self.include?(STREAMING)
end
# @returns [Boolean] whether the `private` directive is present.
def private?
self.include?(PRIVATE)
end
# @returns [Boolean] whether the `public` directive is present.
def public?
self.include?(PUBLIC)
end
# @returns [Boolean] whether the `no-cache` directive is present.
def no_cache?
self.include?(NO_CACHE)
end
# @returns [Boolean] whether the `no-store` directive is present.
def no_store?
self.include?(NO_STORE)
end
# @returns [Boolean] whether the `must-revalidate` directive is present.
def must_revalidate?
self.include?(MUST_REVALIDATE)
end
# @returns [Boolean] whether the `proxy-revalidate` directive is present.
def proxy_revalidate?
self.include?(PROXY_REVALIDATE)
end
# @returns [Integer | Nil] the value of the `max-age` directive in seconds, or `nil` if the directive is not present or invalid.
def max_age
find_integer_value(MAX_AGE)
end
# @returns [Integer | Nil] the value of the `s-maxage` directive in seconds, or `nil` if the directive is not present or invalid.
def s_maxage
find_integer_value(S_MAXAGE)
end
private
# Finds and parses an integer value from a directive.
#
# @parameter value_name [String] the directive name to search for (e.g., "max-age").
# @returns [Integer | Nil] the parsed integer value, or `nil` if not found or invalid.
def find_integer_value(value_name)
if value = self.find{|value| value.start_with?(value_name)}
_, age = value.split("=", 2)
if age =~ /\A[0-9]+\z/
return Integer(age)
end
end
end
end
end
end
end
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