module Responders::HttpCacheResponder
Set HTTP Last-Modified headers based on the given resource. It's used only on API behavior (to_format
) and is useful for a client to check in the server if a resource changed after a specific date or not.
This is not usually not used in html requests because pages contains a lot information besides the resource information, as current_user, flash messages, widgets… that are better handled with other strategies, as fragment caches and the digest of the body.
Public Class Methods
new(controller, resources, options={})
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Calls superclass method
# File lib/responders/http_cache_responder.rb, line 12 def initialize(controller, resources, options={}) super @http_cache = options.delete(:http_cache) end
Public Instance Methods
to_format()
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Calls superclass method
# File lib/responders/http_cache_responder.rb, line 17 def to_format return if do_http_cache? && do_http_cache! super end
Protected Instance Methods
do_http_cache!()
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# File lib/responders/http_cache_responder.rb, line 24 def do_http_cache! timestamp = resources.map do |resource| resource.updated_at.try(:utc) if resource.respond_to?(:updated_at) end.compact.max controller.response.last_modified ||= timestamp if timestamp head :not_modified if fresh = request.fresh?(controller.response) fresh end
do_http_cache?()
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# File lib/responders/http_cache_responder.rb, line 35 def do_http_cache? get? && @http_cache != false && ActionController::Base.perform_caching && persisted? && resource.respond_to?(:updated_at) end
persisted?()
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# File lib/responders/http_cache_responder.rb, line 40 def persisted? resource.respond_to?(:persisted?) ? resource.persisted? : true end