CODEWITHSUNDEEP
rubyruby-on-rails-5
AthleteInAction
AthleteInAction

Reputation: 449

Rails has_many through creating record with relationship

I have a "posts" model, a "teams" model, and a "post_memberships" model. I want "posts" to be related to many "teams" and "teams" to be related to many "posts". I have everything set up properly (i think), but I am unsure of how to create a "post" record with multiple teams related to it.

    class Post < ApplicationRecord

        has_many :post_memberships
        has_many :teams,through: :post_memberships
    end

    class Team < ApplicationRecord

    has_many :post_memberships
    has_many :posts,through: :post_memberships

end

    class PostMembership < ApplicationRecord

    belongs_to :team
    belongs_to :post

end

My "post" form sends a multiple select field of team_id's to the create action in the posts_controller:

    def create
        @post = Post.new(post_params)
        if post_params[:teams]
          post_params[:teams].each do |id|

            @post.teams << Team.find(id)

          end
        end

        respond_to do |format|
          if @post.save
            format.html { redirect_to @post, notice: 'Post was successfully created.' }
            format.json { render :show, status: :created, location: @post }
          else
            format.html { render :new }
            format.json { render json: @post.errors, status: :unprocessable_entity }
          end
        end
      end

def post_params
      params.require(:post).permit(:title, :body, :teams)
    end

I cannot seem to create a "Post" with a "PostMembership".

Upvotes: 1

Views: 435

Answers (1)

Ninigi
Ninigi

Reputation: 1311

There is a caveat in using arrays in strong parameters, so you need to change your post_params method:

def post_params
  params.require(:post).permit(:title, :body, teams: [])
end

That's not quite the end of it though, because now your Post.new receives an array of ids for the teams association, which should throw AssociationTypeMismatch. So we need to change your create method a tiny little bit:

def create
  @post = Post.new(post_params.except(:teams))
  # ...

everything else looks like it should be working :)

Upvotes: 1

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