How should I store variables between method calls in rails?

I'm fairly new to RoR I have a controller and within that controller I need to store an instance variable I create in the new method and reference it again in the create method.

Now because HTTP is stateless the only reasonable way I have found to do this is store the id of the model that the instance variable contains in session[] and then recall this value from session[] again in the create method. I'm just concerned about security using this way of storing the variable's id, I need to make sure that a user can't change the value of what I've stored in sessi开发者_StackOverflowon[]

Is there a better way for me to do this? Is it safe? Or should I try something else?

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If you can't recalculate that model id on every request, using a session is ok.
Here's more info on session security in Rails.

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if you can load the model in the new method, load it from create using the same way you load it in new