Rails: Disable root in JSON for only specific controller actions?

Question

I know how to disable the root element globally, a la Rails 3.1 include_root_in_json or by using ActiveRecord::Base.include_root_in_json = false, but I only want to do this for a few JSON requests (not globally).

So far, I've been doing it like this:

@donuts = Donut.where(:jelly => true)
@coffees = Coffee.all
@breakfast_sandwiches = Sandwich.where(:breakfast => true)

dunkin_donuts_order = {}
dunkin_donuts_order[:donuts] = @donuts
dunkin_donuts_order[:libations] = @coffees
dunkin_donuts_order[:non_donut_food] = @breakfast_sandwiches

Donut.include_root_in_json = false
Coffee.include_root_in_json = false

render :json => dunkin_donuts_order

Donut.include_root_in_json = true
Coffee.include_root_in_json = true

There are about 5 cases where I have to do this, sometimes with more than one model, and it doesn't feel clean at all. I had tried putting this in around_filters, but exceptions were breaking the flow, and that was getting hairy as well.

There must be a better way!

This doesn't directly answer your question, but it does answer the one I came here looking for: You CAN suppress the root on individual calls to `to_json`, e.g. `Donut.to_json(root: false)` — Lambart, Feb 06 '14 at 02:34

Logan Leger · Accepted Answer · 2014-03-13T18:33:41.867

2

The answer is, unfortunately, yes and no.

Yes, what you've done above can arguably be done better. No, Rails won't let you add the root on a per-action basis. The JSON rendering just wasn't built with that sort of flexibility in mind.

That being said, here's what I'd do:

Set include_root_in_json to false for those models which have root depending on the action (such as Donut and Coffee above).
Override as_json to allow for greater flexibility. Here's an example:
```
# in model.rb
def as_json(options = nil)
    hash = serializable_hash(options)
    if options && options[:root]
        hash = { options[:root] => hash }
    else
        hash = hash
    end
end
```
This example will make it so that you can optionally pass a root but defaults to no root. You could alternatively write it the other way.
Since you overrode as_json, you'll have to modify your render calls appropriately. So, for Donut, you'd do render :json => @donut.to_json.

Hope this helps!

edited Mar 13 '14 at 18:33

answered Sep 01 '11 at 03:01

Logan Leger

662
3
10

Thanks. I stopped shooting myself in the foot and switched to [RABL](https://github.com/nesquena/rabl) and have never looked back. So much better! – neezer Sep 02 '11 at 20:38
Good answer. but you don't have to call as_json().to_json because to_json automatically calls your as_json override. – Nada Aldahleh Mar 12 '14 at 16:45
Thanks, @NadaAldahleh. I've clarified that bit in my answer. – Logan Leger Mar 13 '14 at 18:34

score 1 · Answer 2 · answered Feb 06 '13 at 23:16

You can set include_root_in_json per model instance, and it won't affect the class's (see class_attribute in the rails api for a description of this behavior). So you can set a sensible default value on the class level, then set a different value on each instance in the relevant controllers.

Example:

@donuts = Donut.where(:jelly => true).each {|d| d.include_root_in_json = false }

For convenience, you can create a utility method that accepts an array of model instances and sets the value on all of them.

Rails: Disable root in JSON for only specific controller actions?

2 Answers2