instance method `fresh_when`

Ruby on Rails 4.2.9

Since v3.0.20

Available in: v3.0.20 v3.1.12 v3.2.22.5 v4.0.13 v4.1.16 v4.2.9 v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

fresh_when(record_or_options, additional_options = {})

Sets the etag, last_modified, or both on the response and renders a 304 Not Modified response if the request is already fresh.

Parameters:

:etag.
:last_modified.
: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).
:template By default, the template digest for the current controller/action is included in ETags. If the action renders a different template, you can include its digest instead. If the action doesn’t render a template at all, you can pass template: false to skip any attempt to check for a template digest.

Example:

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

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

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.

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

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

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

When rendering a different template than the default controller/action style, you can indicate which digest to include in the ETag:

before_action { fresh_when @article, template: 'widgets/show' }

Parameters

record_or_options req
additional_options opt = {}

Source

# File actionpack/lib/action_controller/metal/conditional_get.rb, line 80
    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, :template)
      else
        record  = record_or_options
        options = { etag: record, last_modified: record.try(:updated_at) }.merge!(additional_options)
      end

      response.etag          = combine_etags(options)   if options[:etag] || options[:template]
      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

Defined in actionpack/lib/action_controller/metal/conditional_get.rb line 80 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActionController::ConditionalGet

Signature

Parameters:

Example:

Parameters