[RUBY] [Rails] Comment function (registration / display / deletion)

A memorandum of implementation of the comment function for posts.


--Manage comments in the Comment table (intermediate table) linked to the User table and Post table. --The Coment table has comment contents, commented post_id, and comment poster user_id columns. -(Premise) Use devise for the user function.


Comment model and table creation

--Create comment model and table (comment content, comment contributor)


% rails g model Comment comment_text:text user:references post:references
% rails g controller Comments
% rails db:migrate

Added association to model.

Comment model

belongs_to :post      # Comment.Get commented posts on post
belongs_to :user      # Comment.Get comment contributor with user

User model

has_many :posts, dependent: :destroy
has_many :comments, dependent: :destroy    # User.Get user comments with comments

validates :comment_text, presence: true, length: { maximum: 1000 }   #Validate the sky, limit the number of characters, etc. ..

Post model

belongs_to :user
has_many :comments, dependent: :destroy    # Post.Get comments for that post with comments

Comment section set up on the detail page

Details page

-#Comment display
= @comments.each do |c|
  = c.user.name
  - if c.user.id == @post.user.id   #Article contributor
    %p Posted by
  = simple_format(c.comment_text)   #Display with line breaks
  = link_to 'Delete', post_comment_path(@post, c), data: {confirm: '本当にDeleteしますか?'}, method: :delete
    -#To delete a comment,@post (parent), @Must be passed to c in comments

-#Post a comment
= form_for [@post, @comment], local: true do |f|   #Since comment is linked to post, write it as an array
  = f.text_area :comment_test
  = f.submit "Post"

Set the routing so that it is linked to the list display page.


resources :posts do   #Nest to link to posts
  resources :comments, only: [:create, :destroy] 

Action definition in controller

Comment registration / deletion action (create / destroy).


% rails g controller comments

comments controller

before_action :set_post
before_action :authenticate_user!    #Allowed only while logged in

def create
  @comment = @post.comments.create(comment_params)
  if @comment.save
    redirect_to blog_path(@post) notice: 'Commented'
    flash.now[:alert] = 'Comment failed'
    render post_path(@post)

def destroy
  @comment = Comment.find(params[:id])
  if @comment.destroy
    redirect_to post_path(@post), notice: 'Deleted comment'
    flash.now[:alert] = 'Failed to delete comment'
    render post_path(@post)

def set_post
  @post = Post.find(params[:post_id])

def comment_params
  params.required(:comment).permit(:comment_text).merge(user_id: current_user.id, post_id: params[:post_id])

Since the comment list is also displayed on the post page (show), comment data can be obtained with posts # show.

posts controller

def show
  @post = Post.find(params[:id])

  @comment = Comment.new     #Instantiate for a form(For adding comments)
  @comments = @post.comments #For comment list display

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