How could I render to a string a JSON representation of a JBuilder view?

Question

I\'m using JBuilder as to return some JSON. I have a index.json.jbuilder that generates the data, and I need to render it to a string. However, I\'m not sure ho

Answer 1

From console:

view = ApplicationController.view_context_class.new("#{Rails.root}/app/views")
JbuilderTemplate.encode(view){|json| json.partial!('path/to/index', @my_object) }

via https://github.com/rails/jbuilder/issues/84#issuecomment-38109709

Answer 2

If the view users.json.jbuilder is at the default path relative to the controller and it cannot find the template, it may be due to a format discrepancy, as it may be trying to look for the html format file. There are two ways to fix this:

1. Have the client GET /users/index.json

   or

2. Specify the formats option when calling render_to_string (also applies to render):

---

#controllers/users_controller.rb
def index
  @users = User.all
  @users_json = render_to_string( formats: 'json' ) # Yes formats is plural
end

This has been verified in Rails 4.1.

Answer 3

Looking at the source code, it looks like you can do:

json_string = Jbuilder.encode do |json|
  json.partial! 'path/to/index', @my_object
end

Answer 4

in controller you can do like this

def index
  json = JbuilderTemplate.new(view_context) do |json|
    json.partial! 'index'
  end.attributes!
  do_something(json)
  render json: json
end

note that you need "_index.json.jbuilder" because it calls partial renderer

Answer 5

I am rendering a collection of users as a json string in the controller like so:

#controllers/users_controller.rb
def index
  @users = User.all
  @users_json = render_to_string( template: 'users.json.jbuilder', locals: { users: @users})
end

#views/users/users.json.jbuilder
json.array!(users) do |json, user|
  json.(user, :id, :name)
end

Answer 6

Following justingordon's tip.

If you are using a React component, you can do the following.

In your controller:

@users = User.all

In your view:

<%= react_component("YourComponentName",
                    props: render('your_template.json.jbuilder')) %>

This was tested on Rails 5.1.