module ActionController::ConditionalGet

def combine_etags(etag)

def combine_etags(etag)
  [ etag, *etaggers.map { |etagger| instance_exec(&etagger) }.compact ]
end

def expires_in(seconds, options = {})

The method will also ensure a HTTP Date header for client compatibility.

See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html for more possibilities.
This method will overwrite an existing Cache-Control header.

expires_in 3.hours, public: true, must_revalidate: true
expires_in 3.hours, public: true
expires_in 20.minutes

instruction, so that intermediate caches must not cache the response.
Sets a HTTP 1.1 Cache-Control header. Defaults to issuing a +private+
def expires_in(seconds, options = {})
  response.cache_control.merge!(
    :max_age         => seconds,
    :public          => options.delete(:public),
    :must_revalidate => options.delete(:must_revalidate)
  )
  options.delete(:private)
  response.cache_control[:extras] = options.map {|k,v| "#{k}=#{v}"}
  response.date = Time.now unless response.date?
end

def expires_now

occur by the browser or intermediate caches (like caching proxy servers).
Sets a HTTP 1.1 Cache-Control header of no-cache so no caching should
def expires_now
  response.cache_control.replace(:no_cache => true)
end

def fresh_when(record_or_options, additional_options = {})

end
fresh_when(@article, public: true)
@article = Article.find(params[:id])
def show

When passing a record, you can still set whether the public header:

end
fresh_when(@article)
@article = Article.find(params[:id])
def show

+updated_at+ and the etag by passing the object itself.
You can also just pass a record where +last_modified+ will be set by calling

If-Modified-Since header and just a 304 Not Modified response if there's a match.
This will render the show template if the request isn't sending a matching etag or

end
fresh_when(etag: @article, last_modified: @article.created_at, public: true)
@article = Article.find(params[:id])
def show

=== Example:

+true+ if you want your application to be cachable by other devices (proxy caches).
* :public By default the Cache-Control header is private, set this to
* :last_modified.
* :etag.

=== Parameters:

304 Not Modified response if the request is already fresh.
Sets the etag, +last_modified+, or both on the response and renders a
def fresh_when(record_or_options, additional_options = {})
  if record_or_options.is_a? Hash
    options = record_or_options
    options.assert_valid_keys(:etag, :last_modified, :public)
  else
    record  = record_or_options
    options = { etag: record, last_modified: record.try(:updated_at) }.merge!(additional_options)
  end
  response.etag          = combine_etags(options[:etag]) if options[:etag]
  response.last_modified = options[:last_modified]       if options[:last_modified]
  response.cache_control[:public] = true                 if options[:public]
  head :not_modified if request.fresh?(response)
end

def stale?(record_or_options, additional_options = {})

end
end
end
# all the supported formats
respond_to do |format|
@statistics = @article.really_expensive_call
if stale?(@article, public: true)

@article = Article.find(params[:id])
def show

When passing a record, you can still set whether the public header:

end
end
end
# all the supported formats
respond_to do |format|
@statistics = @article.really_expensive_call
if stale?(@article)

@article = Article.find(params[:id])
def show

updated_at and the etag by passing the object itself.
You can also just pass a record where +last_modified+ will be set by calling

end
end
end
# all the supported formats
respond_to do |format|
@statistics = @article.really_expensive_call
if stale?(etag: @article, last_modified: @article.created_at)

@article = Article.find(params[:id])
def show

=== Example:

+true+ if you want your application to be cachable by other devices (proxy caches).
* :public By default the Cache-Control header is private, set this to
* :last_modified.
* :etag.

=== Parameters:

it's fresh and we don't need to generate anything and a reply of 304 Not Modified is sent.
request is considered stale and should be generated from scratch. Otherwise,
the client request. If the request doesn't match the options provided, the
Sets the +etag+ and/or +last_modified+ on the response and checks it against
def stale?(record_or_options, additional_options = {})
  fresh_when(record_or_options, additional_options)
  !request.fresh?(response)
end