dynamic_failure_app_handling

🚨 Dynamic Devise::FailureApp for JSON and HTML Fallbacks

Customize Devise::FailureApp to intelligently redirect or render JSON error responses based on Accept headers or user roles. This allows APIs and web clients to share Devise authentication flows without duplicating controllers. Override respond and route methods to dispatch correctly.

# lib/custom_failure.rb
class CustomFailure < Devise::FailureApp
  def respond
    if request.format.json?
      json_error
    else
      super
    end
  end

  def json_error
    self.status = :unauthorized
    self.content_type = 'application/json'
    self.response_body = { error: i18n_message }.to_json
  end
end

# config/initializers/devise.rb
Devise.setup do |config|
  config.warden do |manager|
    manager.failure_app = CustomFailure
  end
end