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# frozen_string_literal: true
module SecureHeaders
class ExpectCertificateTransparencyConfigError < StandardError; end
class ExpectCertificateTransparency
HEADER_NAME = "Expect-CT".freeze
INVALID_CONFIGURATION_ERROR = "config must be a hash.".freeze
INVALID_ENFORCE_VALUE_ERROR = "enforce must be a boolean".freeze
REQUIRED_MAX_AGE_ERROR = "max-age is a required directive.".freeze
INVALID_MAX_AGE_ERROR = "max-age must be a number.".freeze
class << self
# Public: Generate a Expect-CT header.
#
# Returns nil if not configured, returns header name and value if
# configured.
def make_header(config, use_agent = nil)
return if config.nil? || config == OPT_OUT
header = new(config)
[HEADER_NAME, header.value]
end
def validate_config!(config)
return if config.nil? || config == OPT_OUT
raise ExpectCertificateTransparencyConfigError.new(INVALID_CONFIGURATION_ERROR) unless config.is_a? Hash
unless [true, false, nil].include?(config[:enforce])
raise ExpectCertificateTransparencyConfigError.new(INVALID_ENFORCE_VALUE_ERROR)
end
if !config[:max_age]
raise ExpectCertificateTransparencyConfigError.new(REQUIRED_MAX_AGE_ERROR)
elsif config[:max_age].to_s !~ /\A\d+\z/
raise ExpectCertificateTransparencyConfigError.new(INVALID_MAX_AGE_ERROR)
end
end
end
def initialize(config)
@enforced = config.fetch(:enforce, nil)
@max_age = config.fetch(:max_age, nil)
@report_uri = config.fetch(:report_uri, nil)
end
def value
[
enforced_directive,
max_age_directive,
report_uri_directive
].compact.join(", ").strip
end
def enforced_directive
# Unfortunately `if @enforced` isn't enough here in case someone
# passes in a random string so let's be specific with it to prevent
# accidental enforcement.
"enforce" if @enforced == true
end
def max_age_directive
"max-age=#{@max_age}" if @max_age
end
def report_uri_directive
"report-uri=\"#{@report_uri}\"" if @report_uri
end
end
end
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