Split table into two associated tables - ruby-on-rails

Question

I have an app that has a blog feature. Originally when I set this up a post post consisted of a title, body, keywords, and image link. I want to be able to filter posts based on keywords and I think the cleanest way to do this is to move keyword to their own table and associate the two tables. So each posts can have multiple keywords and each keyword can have multiple posts.
I created a migrations and model for keywords.
class CreateKeywords < ActiveRecord::Migration[6.1]
def change
create_table :keywords do |t|
t.string :keyword
t.timestamps
end
end
end
class Keyword < ApplicationRecord
has_and_belongs_to_many :posts
end
I associated that with the posts table and changed the posts model.
class CreatePostsKeywordsJoinTable < ActiveRecord::Migration[6.1]
def change
create_join_table :posts, :keywords do |t|
t.index [:post_id, :keyword_id]
t.index [:keyword_id, :post_id]
end
end
end
class Post < ApplicationRecord
belongs_to :user
has_and_belongs_to_many :keywords
validates :title, presence: true
validates :body, presence: true
accepts_nested_attributes_for :keywords
# validates :keywords, presence: true
end
For now I just commented out the keywords in the Post model. I'm not exactly sure if I need to remove it or not. I already have existing posts that I don't want to lose as part of this switchover so I'm trying to keep that I mind as I figure out how to make this work. Where I'm really confused is what I need to change in the controller.
This is my Post Controller:
require 'pry'
class Api::V1::PostController < ApiController
before_action :authorize_user, except: [:index, :show]
# INDEX /post
def index
render json: Post.all, each_serializer: PostSerializer
end
# SHOW /post/1
def show
render json: Post.find(params[:id]), serializer: PostShowSerializer
end
# CREATE /post/new
def create
binding.pry
post = Post.new(post_params)
post.user = current_user
if post.save
render json: post
else
render json: { errors: post.errors.full_messages }
end
end
# UPDATE /post/update
def update
post = Post.find(params[:id])
if post.update(post_params)
render json: post
else
render json: { errors: post.errors.full_messages }
end
end
# DESTROY /post/destroy
def destroy
post = Post.find(params[:id])
if post.destroy
render json: {destroyed: true}
end
end
protected
def post_params
params.require(:post).permit([:title, :body, :image, :keywords])
end
def authorize_user
if !user_signed_in? || current_user.role != "admin"
redirect_to root_path
end
end
end
In the above state when I get to this part post = Post.new(post_params) I get an error saying NoMethodError (undefined method 'each' for "authorlife":String). If I remove keywords from the post_params I get this error Unpermitted parameter: :keywords
I feel like I am missing one or more steps here but it's been awhile since I've done anything with associated tables like this.
UPDATE:
Followed some of the advice below and I updated the above code to how it currently looks. Current issue is that when I check post_parms in the #create method I'm no longer receiving keywords at all. I checked the frontend and it's sending keywords. I'm assuming it's my post_params that's causing the problem. I've tried adding the keywords nested attribute like this but keywords still isn't showing up in the post_params
def post_params
params.require(:post).permit(:title, :body, :image, :keywords_attributes => [:id, :keyword])
end
This is the WIP for the code I'm trying to implement. I'm not sure what the keywords part is supposed to look like once I get the params situation figured out.
params = { post: {title: post_params["title"], body: post_params["body"], image: post_params["image"], keywords_attributes: [{ keyword: 'keyword title' },]
}}

Answer 1

In the above state when I get to this part post = Post.new(post_params) I get an error saying NoMethodError (undefined method 'each' for "authorlife":String). If I remove keywords from the post_params I get this error Unpermitted parameter: :keywords
You need to setup nested attributes for keywords if you want to update them through a post.
class Post < ApplicationRecord
belongs_to :user
has_and_belongs_to_many :keywords
validates :title, presence: true
validates :body, presence: true
accepts_nested_attributes_for :keywords
end
You can then pass in params structured like this in your controller
params = { post: {
title: 'title', body: "body", keywords_attributes: [
{ text: 'keyword title' },
]
}}
post = Post.create(params[:post])
https://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html
I already have existing posts that I don't want to lose as part of this switchover so I'm trying to keep that I mind as I figure out how to make this work.
It's good practice to remove this not used data anymore. You should write a data migration which moves the existing keywords from the posts table to the keywords table. Something like this
class KeywordsMigrator
def run
Post.all.each do |post|
keyword = Keyword.find_or_create_by(title: post.keyword)
post.keywords << keyword
end
end
end
Finally you can drop the keyword column from post.
You haven't really mentioned the current structure of the posts table so I assume you have a keyword column there. If you have a keywords column you have to name your association different until you remove the column otherwise you will run into troubles. For example you rename it to keywords_v1 and specify the class_name.
class Post < ApplicationRecord
belongs_to :user
has_and_belongs_to_many :keywords_v1, class_name: "Keyword"
validates :title, presence: true
validates :body, presence: true
end
Or you rename the column first to something like deprecated_keywords.