Creating multiple participants in the User model

问题

I'm trying to set up a complex association where the User model is used two times. Once to create the leader of a discussion and then to create the participants for the discussion.

First, do I have the associations correct in order to call multiple participants (users) for a discussion led by one user (leader)?

User

has_many :discussions, foreign_key: :leader_id
belongs_to :received_discussions, class_name: 'Discussion'

attr_accessible :participant_id

Discussion

belongs_to :leader, class_name: 'User'
has_many :participants, class_name: 'User', foreign_key: :participant_id

And second, how would I build the action to assign multiple users as participants?

Form:

  .offset2.span7.mtop20
    = simple_form_for @discussion, html: { multipart: true } do |f|
      %fieldset.well
        .mtop10
          = f.input :participant_ids, label: 'Send to: (select from members you follow)', as: :select, collection: participants_for_discussion, input_html: { class: 'followed-ids-select', multiple: true }
          = f.input :title
          = f.input :description
        .form-actions
          = f.submit 'Send', name: 'send_now', class: 'btn btn-primary btn-large pull-right mleft10'
          = f.submit 'Save and View Draft', name: 'save_draft', class: 'btn btn-large pull-right'

discussion_controller

def create
  #not sure how to assign the participants in the action
  @discussion = current_user.discussions.build(params[:discussion])


  if @discussion.save
    redirect_to @discussion, notice: draft_or_sent_notice
  else
    render :new
  end
end

The error I'm getting is Can't mass-assign protected attributes: participant_ids

回答1:

First of all you want to have has_and_belongs_to_many between User and Discussion, both when a user is a leader or participant.

First you should make the decision if you want to user habtm or has_many :through association http://guides.rubyonrails.org/association_basics.html#choosing-between-has-many-through-and-has-and-belongs-to-many

Then remodel your associations and the rest of your problems should solve themselves.

来源：https://stackoverflow.com/questions/17622827/creating-multiple-participants-in-the-user-model

标签

ruby-on-rails

controller

associations

has-many