Serialized attribute saved as HashWithIndifferentAccess in database

My Booking model has: serialize :custom_data, Hash

From the console it works as expected saving values to the custom_data attribute.

But when having a form with parameters like this: booking[custom_data][hello] and creating a new object in the controller like this: params[:booking] ), values are saved in the database with added metadata like this: — !ruby/hash:ActiveSupport::HashWithIndifferentAccess

How can get rid of the HashWithIndifferentAccess-metadata when saving from a form?


You can check condition like this

if params[:booking].kind_of? HashWithIndifferentAccess

// logic here


I fixed it by converting it to a hash:

@booking.custom_data = params[:booking][:custom_data].to_hash if params[:booking][:custom_data]

I do think that Rails should handle this automatically though. There is no way to see this error by just using rails. You have to look at the actual data stored in the database to see that it stores more than just the actual data. I would suspect there are more people saving serialised attributes from a form and will have this issue without realising it.

I don’t follow that logic at all. If you’re interacting with a serialized column by any other means than loading it from the DB as a Ruby object, you are DOING IT WRONG. If you really, really want to interact with hashes in the DB, check out things like Postgres’s Hstore:

–Matt Jones