Basic usage

First, run the json_errors:install generator:

> rails g json_errors:install
      create  config/initializers/json_errors.rb

It creates the initializer file with config. Check out the file and uncomment what you need.

Then include JsonErrors::Rescuer to your JSON API controller and start raising errors.

class UsersController < ApplicationController
  include JsonErrors::Rescuer

  def create
    user = User.create!(params.require(:name))

    head :created
  end
end

Be sure to use error throwing methods everywhere, like create!, save!, find_by!, etc. The gem will rescue from any exception and respond with a properly formatted JSON body with a custom error code.

No need for rescue_from or rendering the JSON error body. Every error is rescued, logged, formatted and rendered. The client application will receive a JSON body like this:

{
  "code":1010,
  "message":"The parameter 'name' is missing or value is empty"
}