docbrown/app/controllers/concerns/caching_headers.rb
Ben Halpern bc248f17e7
Skip edge caching for private forems (#10817)
* Skip edge caching for private forems

* Add test

* Update spec/requests/stories_index_spec.rb

* Adjust comment

* Also check other cache-related headers
2020-10-13 13:36:20 -04:00

47 lines
1.9 KiB
Ruby

module CachingHeaders
extend ActiveSupport::Concern
# The following is from the now deprecated fastly-rails gem
# https://github.com/fastly/fastly-rails/tree/master/lib/fastly-rails/action_controller
# Sets Cache-Control and Surrogate-Control HTTP headers
# Surrogate-Control is stripped at the cache, Cache-Control persists (in case of other caches in front of fastly)
# Defaults are:
# Cache-Control: 'public, no-cache'
# Surrogate-Control: 'max-age: 86400' - 1 day in seconds
# custom config example:
# {cache_control: 'public, no-cache, maxage=xyz', surrogate_control: 'max-age: 100'}
def set_cache_control_headers(
max_age = 1.day.to_i,
surrogate_control: nil,
stale_while_revalidate: nil,
stale_if_error: 26_400
)
return unless SiteConfig.public # Only public forems should be edge-cached based on current functionality.
request.session_options[:skip] = true # no cookies
response.headers["Cache-Control"] = "public, no-cache" # Used only by Fastly.
response.headers["X-Accel-Expires"] = max_age.to_s # Used only by Nginx.
response.headers["Surrogate-Control"] = surrogate_control.presence || build_surrogate_control(
max_age, stale_while_revalidate: stale_while_revalidate, stale_if_error: stale_if_error
)
end
# Sets Surrogate-Key HTTP header with one or more keys strips session data
# from the request.
def set_surrogate_key_header(*surrogate_keys)
request.session_options[:skip] = true # No Set-Cookie
response.headers["Surrogate-Key"] = surrogate_keys.join(" ")
end
private
def build_surrogate_control(max_age, stale_while_revalidate: nil, stale_if_error: 26_400)
surrogate_control = "max-age=#{max_age}"
surrogate_control += ", stale-while-revalidate=#{stale_while_revalidate}" if stale_while_revalidate
surrogate_control += ", stale-if-error=#{stale_if_error}" if stale_if_error
surrogate_control
end
end