Support json builders for generating props

[BilalBudhani]

From the Rails way of doing things writing props in controllers feels a little out of place, Consider this example from PingCRM

json.data(paged_contacts) do |contact|
   json.(contact, :id, :name, :phone, :city, :deleted_at)
   if contact.organization
     json.organization(contact.organization, :name)
   end
 end

I imagine in a more complicated app, this logic will start growing into multi line conditions making controllers fat.

It would be great if building props json can be pushed to view layer by leveraging existing robust engines like Jbuilder, props_template etc. instead.

For example

class EventsController < ApplicationController
  use_inertia_view_props :jbuilder # <- tell inertia to use jbuilder templating engine 

  def index
    @events = Event.all
    # props -> app/views/events/index.json.jbuilder
  end
end

And

class EventsController < ApplicationController

  def index
    @events = Event.all
    render inertia: 'Events/Index', template: 'index'
    # props -> app/views/events/index.json.jbuilder
  end
end

This would simplify controllers and unlock capabilities of json builder engines for better usability.

Moreover, I see a possibility of projects that already use json builders for sending data to frontends can progressively adapt Inertia by reusing their existing templates.

[jho406]

Hi! Author of props_template here!

props_template also has support for deferred props via the defer option. When you use that option you can gather all deferred props using json.deferred! to iterate through through all deferred props to build an inertia 2 response.

You can also extend it and make it specific for inertia using the extension manager here

[BrandonShar]

This is a super cool idea, I might hack around on it this weekend. I really like the pattern.

[skryukov]

@BrandonShar here's a quick snippet I posted in the Discord (just in case):

class InertiaExampleController < ApplicationController
  def inertia_view_assigns
    template = lookup_context.find_template(action_name, controller_path)
    json = JbuilderTemplate.new(self)
    binding.eval template.source
    json.attributes!
  end

  def index
    # or set config.default_render: true
    render(inertia: true)
  end
end

But to be honest, I'd love to introduce a plugin system here, so we could support different serializers (and allow users to hook into the process as well).

[bknoles]

@skryukov are there any analogous plugin systems you have in mind we could use for inspiration?

[dsh0416]

@skryukov @BrandonShar Brilliant idea. But it seems that if you try to use json.partial! inside your templates, it might raise double rendering errors.

The following code works, but really weird.

def inertia_view_assigns
  return {} unless lookup_context.exists?(action_name, controller_path)

  JSON.parse(render_to_string(formats: [:json]))
end

[BilalBudhani]

Came across inertia-builder gem by @rodrigotavio91 which builds on this concept. It also has support for defer!, always! and optional!

[bknoles]

Yea inertia-builder is cool! I haven't used it in a project yet, but the API looks really clean. Nicely done @rodrigotavio91!

[rodrigotavio91]

Thanks guys, I need to battle test it more before calling it production ready, so I'd love for more people to try it out and report any issue. I think it's easy to progressively adopt it if you don't have default_render enabled.

Besides making the code cleaner, this gem also enables creating props partials (which allows you to cache them) and the props are lazily evaluated by default, which is handy.