Can store hash in a cookie?

问题:

Anyone know if I can put a hash in the cookie? Something like this: cookies [: test] = {: top => 5,: middle => 3,: bottom => 1}

Thanks

回答1:

I woud look into serializing the hash to store it. Then deserialize it to retrieve it.

When you serialize a hash, the result will be an encoded string. This string can be decoded to get the original object back.

You could use YAML or JSON for this. Both are nicely supported in Ruby.

---

A YAML example

require "yaml"

cookies[:test] = YAML::dump {a: 1, b: "2", hello: "world"}
# => "---\n:a: 1\n:b: '2'\n:hello: world\n"

YAML::load cookies[:test]
# => {a: 1, b: 2, c: "world"}

---

A JSON example

require "json"

cookies[:test] = JSON.generate {a: 1, b: "2", hello: "world"}
# => '{"a":1,"b":"2","hello":"world"}'

JSON.parse cookies[:test]
# => {"a"=>1, "b"=>"2", "hello"=>"world"}

Note: when using JSON.parse, the resulting object will have string-based keys

回答2:

With Rails 4.1 I had to use the parentheses like this. Without that it gave an error.

cookies[:test] = JSON.generate({a: 1, b: "2", hello: "world"})

回答3:

There are a number of ways which it is possible (i.e. storing a string and evaling that value, SCARY!). This is a simple way.

cookies[:test_top]    = 5
cookies[:test_middle] = 3
cookies[:test_bottom] = 1

You can also convert to JSON and then parse it when loading the cookie.

Newer versions of Rails include automatically serialization using the session object.