#321 HTTP Caching pro

Jan 30, 2012 | 15 minutes | Performance, Views, Caching

With HTTP response headers you can the cache in the user's browser and proxies. Etags, Last-Modified, Cache-Control and Rack::Cache are all covered here

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          terminal
        
curl -I http://localhost:3000/
curl -I http://localhost:3000/ -c cookies.txt
curl -I http://localhost:3000/ -b cookies.txt
curl -I http://localhost:3000/ -b cookies.txt --header 'If-None-Match: "8c90bb6e63dc2868f076c82a939f6654"'
curl -I http://localhost:3000/products/1
curl -I http://localhost:3000/products/1 --header 'If-None-Match: "6b110718516575b1a14131d2c7668af5"'
curl -I http://localhost:3000/products/1 --header 'If-Modified-Since: Sat, 28 Jan 2012 18:25:53 GMT'
rake middleware

          products_controller.rb
        
def index
  @products = Product.scoped
  fresh_when last_modified: @products.maximum(:updated_at)
end

def show
  @product = Product.find(params[:id])
  expires_in 5.minutes
  fresh_when @product, public: true
  # or:
  # if stale? etag: @product, last_modified: @product.updated_at, public: true
  #  render ...
  # end
end

          config/environments/development.rb
        
config.action_controller.perform_caching = true

          layouts/application.html.erb
        
<%= csrf_meta_tag unless response.cache_control[:public] %>