omni.rb

OmniAuth.config.full_host = ->(env) {
  scheme = if env['HTTPS'] == 'on' or env['HTTP_X_FORWARDED_SSL'] == 'on'
    'https'
  elsif env['HTTP_X_FORWARDED_PROTO'].present?
    env['HTTP_X_FORWARDED_PROTO'].split(',').first.strip
  else
    env['rack.url_scheme']
  end

  hostname = env['HTTP_X_FORWARDED_HOST'].present? ? env['HTTP_X_FORWARDED_HOST'] : env['HTTP_HOST']
  port     = env['HTTP_X_FORWARDED_PORT'].present? ? ":#{env['HTTP_X_FORWARDED_PORT']}" : ''
  
  "#{scheme}://#{hostname}#{port}"
}