ruby - Rendering partials / view in a rake task / background job / model in Rails 4 -

i've read lot on rendering rails partials , views in rake tasks / background jobs / models. vast majority of things have found on stackoverflow , web describe approaches working in rails 3, seem outdated , didn't them work (even quite time spent experimenting).

so, how can render partial in background job in rails 4?

here's best approach i've worked out far (demonstrated in console).

c = applicationcontroller.new result = c.render_to_string(partial: 'tweets/tweet', locals: {tweet: tweet.first}) # => #   tweet load (0.8ms)  select "tweets".* "tweets" order "tweets"."id" asc limit 1 #   author load (0.6ms)  select "authors".* "authors" "authors"."id" = $1 order "authors"."id" asc limit 1  [["id", 1]] #   status load (0.6ms)  select "statuses".* "statuses" "statuses"."twitter_id" = 367523226848866304 limit 1 #   rendered tweets/_tweet_body.html.slim (17.5ms) #   rendered tweets/_resolved_tweet.html.slim (23.7ms) #   rendered tweets/_tweet.html.slim (28.1ms) # actionview::template::error: undefined method `tweet_path' #<#<class:0x007fb21bf797a0>:0x007fb21cb009e8> # /users/thomasklemm/.rbenv/versions/2.0.0-p195/lib/ruby/gems/2.0.0/gems/actionpack-4.0.0/lib/action_dispatch/routing/polymorphic_routes.rb:129:in `polymorphic_url' 

any ideas? in advance!

update: tweet_path mentioned above indeed not defined. error resulted linking path = link_to 'tweet', [@project, tweet] (slim templates) using instance variable present in views inheriting controller, not when rendered outside of context. solved going through appropriate association instead = link_to 'tweet', [tweet.project, tweet].

here's compiled lots of sources , works me in rails 4.

with renderer class, should able render rails 4 views , partials in context, background jobs, service objects, models, workers, name it.

# app/services/renderer.rb # render views , partials in rake tasks, # background workers, service objects , more # # use: # # class myservice #   def render_stuff #     result = renderer.render(partial: 'tweets/tweet', locals: {tweet: tweet.first}) #     # or #     result = renderer.render(tweet.first) #   end # #   private # #   def renderer #     @renderer ||= renderer.new.renderer #   end # end # class renderer   def renderer     controller = applicationcontroller.new     controller.request = actiondispatch::testrequest.new     viewrenderer.new(rails.root.join('app', 'views'), {}, controller)   end end  # app/services/view_renderer.rb # helper class renderer class viewrenderer < actionview::base   include rails.application.routes.url_helpers   include applicationhelper    def default_url_options      {host: rails.application.routes.default_url_options[:host]}   end end 

update:

there seems easier solution: http://makandracards.com/makandra/17751-render-a-view-from-a-model-in-rails

applicationcontroller.new.render_to_string(   :template => 'users/index',   :locals => { :@users => @users } ) # mind weird syntax set @ variables in :locals. 

update 2:

there's gem called render_anywhere allows calling "render" anywhere: models, background jobs, rake tasks, etc.

update 3:

in rails 5, renderer has been extracted , can used standalone background jobs , other places:

applicationcontroller.renderer.render(   partial: 'messages/message',   locals: { message: message } ) 

for rails <= 4.2, functionality can backported backport_new_renderer gem.