module ActionController::ConditionalGet

:doc:
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, 'max-stale' => 5.hours, :public => true
expires_in 3.hours, :public => true
expires_in 20.minutes
Examples:

intermediate caches must not cache the response.
Sets a HTTP 1.1 Cache-Control header. Defaults to issuing a private instruction, so that

def expires_in(seconds, options = {}) #:doc:
  response.cache_control.merge!(:max_age => seconds, :public => options.delete(:public))
  options.delete(:private)
  response.cache_control[:extras] = options.map {|k,v| "#{k}=#{v}"}
end

:doc:
intermediate caches (like caching proxy servers).
Sets a HTTP 1.1 Cache-Control header of no-cache so no caching should occur by the browser or

def expires_now #:doc:
  response.cache_control.replace(:no_cache => true)
end

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

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

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:

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

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

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

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:

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