在整个Rails应用程序中禁用HTML响应格式

Question

I use pure javascript frontend template to handle all requests with Rails via JSON API

However,

I don't know why sometimes the exception will give me the error message in HTML format.

Because I've already set the API request format in JSON

Controller (I only keep format.json in the controller)

format.json { render json: @city.errors, status: :unprocessable_entity }

Route.rb

  namespace :api do
    namespace :v1, defaults: {format: 'json'} do
    resources country do
        resources city do
            .....
        end
    end
    end
  end

Answer 1

I don't know why sometimes the exception will give me the error message in HTML format.

It's not dependent on your app, it is all about the request and request headers, if somebody make a request as html rails try to render html.

Answer 2

Exceptions are rendered in html outside of your controller. You should do it by yourself:

your controller:

begin
  code_for_ok
rescue #some exception
  render json: @city.errors, status: :unprocessable_entity
end