Cookies can typically store 4096 bytes.
Raised when storing more than 4K of session data.
Cookies are read and written through ActionController#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.
Examples of writing:
# Sets a simple session cookie. # This cookie will be deleted when the user's browser is closed. cookies[:user_name] = "david" # Cookie values are String based. Other data types need to be serialized. cookies[:lat_lon] = JSON.generate([47.68, -122.37]) # Sets a cookie that expires in 1 hour. cookies[:login] = { value: "XJ-122", expires: 1.hour.from_now } # Sets a signed cookie, which prevents users from tampering with its value. # The cookie is signed by your app's `secrets.secret_key_base` value. # It can be read using the signed method `cookies.signed[:name]` cookies.signed[:user_id] = current_user.id # Sets a "permanent" cookie (which expires in 20 years from now). cookies.permanent[:login] = "XJ-122" # You can also chain these methods: cookies.permanent.signed[:login] = "XJ-122"
Examples of reading:
cookies[:user_name] # => "david" cookies.size # => 2 JSON.parse(cookies[:lat_lon]) # => [47.68, -122.37] cookies.signed[:login] # => "XJ-122"
Example for deleting:
cookies.delete :user_name
Please note that if you specify a :domain when setting a cookie, you must also specify the domain when deleting the cookie:
cookies[:name] = { value: 'a yummy cookie', expires: 1.year.from_now, domain: 'domain.com' } cookies.delete(:name, domain: 'domain.com')
The option symbols for setting cookies are:
-
:value
- The cookie's value. -
: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 www.example.com and want to share session with user.example.com set:domain
to:all
. Make sure to specify the:domain
option with:all
orArray
again when deleting cookies.domain: nil # Does not sets cookie domain. (default) domain: :all # Allow the cookie for the top most level domain and subdomains. domain: %w(.example.com .example.org) # Allow the cookie for concrete domain names.
-
:expires
- The time at which this cookie expires, as a Time object. -
:secure
- Whether this cookie is only transmitted to HTTPS servers. Default isfalse
. -
:httponly
- Whether this cookie is accessible via scripting or only HTTP. Defaults tofalse
.