ruby - Rails: Render view from outside controller

Question

I'm trying to create an HTML string using a view. I would like to render this from a class that is not a controller. How can I use the rails rendering engine outside a controller? Similar to how ActionMailer does?

Thanks!

Answer 1

Rails 5 now supports this in a much more convenient manner that handles creating a request and whatnot behind the scenes:

rendered_string = ApplicationController.render(
  template: 'users/show',
  assigns: { user: @user }
)

This renders app/views/users/show.html.erb and sets the @user instance variable so you don't need to make any changes to your template. It automatically uses the layout specified in ApplicationController (application.html.erb by default).

The test shows a handful of additional options and approaches.