ruby on rails - uninitialized constant ActionView::CompiledTemplates::UserAgent -

ruby on rails - uninitialized constant ActionView::CompiledTemplates::UserAgent -

i using useragent gem.

i have next code in view

<%= user_agent = {} %> <% user_agent = useragent.parse(request.env["http_user_agent"]) %> app: <%= user_agent.application %> # mozilla/5.0 (macintosh; intel mac os x 10.8; rv:22.0) browser: <%= user_agent.browser %> # firefox version: <%= user_agent.version %> # 22.0 platform: <%= user_agent.platform %> # macintosh mobile: <%= user_agent.mobile? %> # false os: <%= user_agent.os %> # os x 10.8

and getting next error.

uninitialized constant actionview::compiledtemplates::useragent

for reason, useragent isn't thing...

how did implement gem? if using bundler, create sure included gem in gemfile. may need require it, (probably) gem 'useragent', :require=>'useragent'. if not, may need require somewhere, before utilize it.

it might not available in current namespace, weird reason, in case can utilize like: <% user_agent = ::useragent.parse(request.env["http_user_agent"]) %>.

ruby-on-rails ruby gem