Real-time comment function with Action Cable (2/2)

★ Implement real-time comment function with Action Cable

As a comment function linked to posts without creating a new chat room Implement that allows you to post and delete comments in real time

This time we will implement the real-time comment function The link below summarizes a little about Action Cable. To the basics of the comment function (1/2)

❶ Check the controller

After creating and destroying comments Specify the information you want to send as data to javascript here

#comments_controller.rb
class CommentsController < ApplicationController
  def create
    @post = Post.find(params[:post_id])
    #Create a comment associated with a post
    @comment = @post.comments.build(comment_params)
    @comment.user_id = current_user.id
    if @comment.save
      ActionCable.server.broadcast 'message_channel', content: @comment, user: @comment.user, date: @comment.created_at.to_s(:datetime_jp), id: @comment.id,post: @comment.post
    end
  end

  def destroy
    @post = Post.find(params[:post_id])
    @comment = Comment.find(params[:id])
    if @comment.destroy
      ActionCable.server.broadcast 'delete_channel', id: @comment.id
    end
  end

  private
  def comment_params
    params.require(:comment).permit(:content, :post_id, :user_id).merge(user_id: current_user.id)
  end
end

❷ Connect controller and javascript file with channel

#message_channel.rb
class MessageChannel < ApplicationCable::Channel
  def subscribed
    stream_from "message_channel"
  end

  def unsubscribed
    # Any cleanup needed when channel is unsubscribed
  end
end

#delete_channel.rb
class DeleteChannel < ApplicationCable::Channel
  def subscribed
    stream_from "delete_channel"
  end

  def unsubscribed
    # Any cleanup needed when channel is unsubscribed
  end

end

❸ Describe the process you want to implement in real time with javascript

Display date and time specified by format Organize notation for embedding code in character strings

#message_channel.js
import consumer from "./consumer"
window.addEventListener('load', function(){

consumer.subscriptions.create("MessageChannel", {
  connected() {
    // Called when the subscription is ready for use on the server
  },

  disconnected() {
    // Called when the subscription has been terminated by the server
  },

  received(data) {
    const html = `<div id="test-${data.id}">
    <p><a href="/users/${data.user.id}">@${data.user.nickname}</a></p>
                  <span style="font-weight:bold;">${data.content.content}</span>
                  &nbsp;${data.date}
                  &nbsp;<a id="delete-btn", data-method="delete" href="/posts/${data.post.id}/comments/${data.id}"><button id="${data.id}">Delete</button></a>
                  </div>`;

    const messages = document.getElementById('collapseExample');
    const newMessage = document.getElementById('comment_content');
    messages.insertAdjacentHTML('beforeend', html);
    newMessage.value='';

      var countComment = document.getElementsById('collapseExample').length;
      console.log(countComment)
  }
});
})

flow of delete_channel.js Put the comment ID in the comment container element in advance.

#_index.html.erb
<li class="comment-container" id="comment-#{comment.id}">

Find this and delete it

Also, by setting (comment-$ {data.id}) I only get the ID of the comment I'm sending with @ comment.id on the controller, so I don't think it's necessary Since not only 137 but also an extra part was sent like id: 137, the specification was made finer.

It is important to use the debugger diligently and implement it while checking.

#delete_channel.js
import consumer from "./consumer"
window.addEventListener('load', function(){
consumer.subscriptions.create("DeleteChannel", {
  connected() {
    // Called when the subscription is ready for use on the server
  },

  disconnected() {
    // Called when the subscription has been terminated by the server
  },
 
  received(data) {

    const test = document.getElementById(`${data.id}`)
    const container = document.getElementById(`test-${data.id}`);
    console.log(container)
    container.remove();
    
    },
    
});
})

★ The following are possible alternative plans for the deletion function implemented this time.

After inserting an element with insertAdjacentHTML, add an onclick event handler to that element and send a delete request within the handler

You can shorten the description by using JQuery, but this time I implemented it only with Javascript for studying