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Diffstat (limited to 'guides/source/upgrading_ruby_on_rails.md')
-rw-r--r-- | guides/source/upgrading_ruby_on_rails.md | 44 |
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diff --git a/guides/source/upgrading_ruby_on_rails.md b/guides/source/upgrading_ruby_on_rails.md index da124e21a4..d58024df3d 100644 --- a/guides/source/upgrading_ruby_on_rails.md +++ b/guides/source/upgrading_ruby_on_rails.md @@ -111,6 +111,50 @@ in your application, you can add an initializer file with the following content: This would transparently migrate your existing `Marshal`-serialized cookies into the new `JSON`-based format. +When using the `:json` or `:hybrid` serializer, you should beware that not all +Ruby objects can be serialized as JSON. For example, `Date` and `Time` objects +will be serialized as strings, and `Hash`es will have their keys stringified. + +```ruby +class CookiesController < ApplicationController + def set_cookie + cookies.encrypted[:expiration_date] = Date.tomorrow # => Thu, 20 Mar 2014 + redirect_to action: 'read_cookie' + end + + def read_cookie + cookies.encrypted[:expiration_date] # => "2014-03-20" + end +end +``` + +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. + +If you use the cookie session store, this would apply to the `session` and +`flash` hash as well. + +### Flash structure changes + +Flash message keys are +[normalized to strings](https://github.com/rails/rails/commit/a668beffd64106a1e1fedb71cc25eaaa11baf0c1). They +can still be accessed using either symbols or strings. Lopping through the flash +will always yield string keys: + +```ruby +flash["string"] = "a string" +flash[:symbol] = "a symbol" + +# Rails < 4.1 +flash.keys # => ["string", :symbol] + +# Rails >= 4.1 +flash.keys # => ["string", "symbol"] +``` + +Make sure you are comparing Flash message keys against strings. + ### Changes in JSON handling There are a few major changes related to JSON handling in Rails 4.1. |