ruby on rails - strong parameters doesn't allow to create nested attributes with json. ActiveRecord::AssociationTypeMismatch error -

i have 2 models: conference , talks. conference has_many talks ,

accepts_nested_attributes_for :talks, :allow_destroy => true 

params posting looks that:

{"id"=>"2", "name"=>"rails4444", "tags"=>"ruby, rails, backbone, javascript", "date"=>"2014-02-22", "organizer"=>"backbonemeetupgroup", "description"=>"conference cool speakers", "talks"=>{"title"=>"fdsf", "video_url"=>"fdsf"},  

where setting talks should created in database.

my html looks that:

<input type="text" name="talks[title]" placeholder="talk title" /> <input type="text" name="talks[video_url]" placeholder="url" /> 

and when updating conference model talks gives me error:

activerecord::associationtypemismatch (talk(#70154003251480) expected, got array(#70154000241560)): app/controllers/conferences_controller.rb:25:in `update'

my controller looks that:

 def update     @single = conference.find params[:id]     if @single.update_attributes conference_params       render "conferences/show"     else       respond_with @single     end   end      def conference_params     params.permit(:name, :tags, :date, :organizer, :description, :place, :talks => [:conference_id, :id, :title, :video_url])   end 

why activerecord::associationtypemismatch error , how can fix it?

as conference has_many talks, need array of talks nested attributes, not single one.

your input fields need names like:

<input type="text" name="conference[talks_attributes][0][title]" /> 

to work accepts_nested_attributes. normal way create input use

<%= fields_for :talks |ff| %>   <%= ff.text_field :title %> <% end %> 

see rails guide on form helpers.

and need use talks_attributes in permit medbo suggests.