ruby on rails 4 - With Active Model Serializers, how do you render a partial? -

i'm creating newsfeed , have json response set active model serializers gem. i'd render regular erb partial , have 1 of attributes in json.

controllers/posts_controller.rb:

def index   @posts = post.all   respond_to |format|     format.json { render json: @posts.to_a, each_serializer: postserializer }   end end 

serializers/post_serializer.rb:

def event_html   applicationcontroller.new.render_to_string(:partial => 'events/event', :locals => { :event => object.event }) if object.event end 

unfortunately, view has code uses helpers , request object (urls), , i'm getting errors when try this.

events/_event.html.erb:

<div class="event">   <h4 class="title"><%= link_to event.name, event %></h4>   <div class="date"><%= date_range event.start_at, event.end_at %></div>   <div class="description"><%= event.description.html_safe %></div> </div> 

undefined method `host' nil:nilclass

any ideas of way solve problem?

that happens because controller lacks response attribute.

you may set request controller follows:

def event_html   applicationcontroller.new.tap {|c|       c.request = actioncontroller::testrequest.new(host: "localhost")   }.render_to_string(:partial => 'events/event', :locals => { :event => object.event }) if object.event  end 

however, case pass existing controller context serializer

controllers/posts_controller.rb:

def index   @posts = post.all   respond_to |format|     format.json { render json: @posts.to_a, each_serializer: postserializer, context: self }   end end # ... or ... def default_serializer_options   {     context: self   } end 

serializers/post_serializer.rb:

def event_html   context.render_to_string(:partial => 'events/event', :locals => { :event => object.event }) if object.event end