Cookies are read and written through Amber::Base::Controller#cookies.

The cookies being read are the ones received along with the request, the cookies being written will be sent out with the response. Reading a cookie does not get the cookie object itself back, just the value it holds.

It's advisable that you only store simple data (strings and numbers) in cookies. If you have to store complex objects, you would need to handle the conversion manually when reading the values on subsequent requests.

Amber also has an encrypted cookie jar for storing sensitive data. The encrypted cookie jar encrypts the values in addition to signing them, so that they cannot be read by the end user.

Examples of writing

class CommentsController < ApplicationController
def new
# Auto-fill the commenter's name if it has been stored in a cookie
@comment = cookies[:commenter_name])
def create
@comment =[:comment])
flash[:notice] = "Thanks for your comment!"
if params[:remember_name]
# Remember the commenter's name.
cookies[:commenter_name] =
# Delete cookie for the commenter's name cookie, if any.
redirect_to @comment.article
render action: "new"

Examples of reading

cookies[:user_name] # => "david"
cookies.size # => 2
JSON.parse(cookies[:lat_lon]) # => [47.68, -122.37]
cookies.encrypted[:discount] # => 45

Please note that if you specify a :domain when setting a cookie, you must also specify the domain when deleting the cookie:

cookies.set "name", "a yummy cookie", expires: 1.year.from_now, domain: ""
cookies.delete "name", domain: ""

The optional parameters for setting cookies are:

path # The path for which this cookie applies. Defaults to the root of the application.
domain # The domain for which this cookie applies so you can restrict to the domain level.
# If you use a schema like and want to share session with
# set :domain to :all. Make sure to specify the :domain option with :all or Array again
# when deleting cookies.
domain: nil # Does not set cookie domain. (default)
domain: :all # Allow the cookie for the top most level domain and subdomains.
domain: %w( # Allow the cookie for concrete domain names.
tld_length # When using :domain => :all, this option can be used to explicitly set the TLD length
# when using a short (<= 3 character) domain that is being interpreted as part of a TLD.
# For example, to share cookies between and, set :tld_length to 1.
expires # The time at which this cookie expires, as a Time object.
secure # Whether this cookie is only transmitted to HTTPS servers. Default is false.
httponly # Whether this cookie is accessible via scripting or only HTTP. Defaults to false.