【Rails】Action Cableで非同期なチャット機能を実装する方法

$ rails g model chat

class ChatsController < ApplicationController
  def index
    @my_chats=current_user.chats
    @chat_partners=User.where.not(id:current_user.id)#自分以外
  end

  def show
    @partner=User.find(params[:id])
    @chats_by_myself=Chat.where(user_id: current_user.id,partner_id: @partner.id)
    @chats_by_other=Chat.where(user_id: @partner.id,partner_id: current_user.id)
    @chats=@chats_by_myself.or(@chats_by_other)#リレーションオブジェクト達を結合する
    @chats=@chats.order(:created_at)
  end
end

<table class="rooms">
  <tbody>
    <tr>
      <td>
        <%@chat_partners.each do |chat_partner|%>
          <%=link_to "#{chat_partner.email}さんとのトークルーム","/chats/#{chat_partner.id}"%>
        <%end%>
      </td>
    </tr>
  </tbody>
</table>
<%=link_to("ログインページへ","/")%>
<%=link_to("ログアウトする","/users/sign_out",method: :delete)%>

<h2 style="text-align:center"><%="#{@partner.email}さんとのチャット"%></h2>
<div id="chats">
  <% @chats.each do |chat|%>
    <%if chat.user_id==current_user.id%>
      <div class="mycomment">
        <p><%=chat.sentence%></p>
      </div>
    <%else%>
      <div class="fukidasi">
        <div class="faceicon">
          <img src="/assets/profile.png" alt="相手">
        </div>
        <div class="chatting">
          <div class="says">
            <p><%=chat.sentence%></p>
          </div>
        </div>
      </div>
    <%end%>
  <%end%>
</div>
<form id="send-form">
  <input type="text" id="sentence" placeholder="入力してね" style="width:30%;">
  <input type="submit" value="送信" id="send">
  <input id="current_user_id" type="hidden" value= "<%=current_user.id%>">
  <input id="partner_id" type="hidden" value= "<%=@partner.id%>">
</form>
<%=link_to("ログアウトする","/users/sign_out",method: :delete)%>

/************************************
** トークルーム一覧
************************************/
.rooms{
  margin:0 auto;
  background-color:#fdfdfd;
  border: 2px solid #eee;
  padding:1em 2em;
}
/************************************
** チャットの吹き出し
************************************/
#chats{
  padding: 20px 10px;
  max-width: 450px;
  margin: 15px auto;
  text-align: right;
  font-size: 14px;
  background: #7da4cd;
}
.fukidasi {
  width: 100%;
  margin: 10px 0;
  overflow: hidden;
}
.fukidasi .faceicon {
  float: left;
  margin-right: -50px;
  width: 40px;
}
.fukidasi .faceicon img{
  width: 90%;
  height: auto;
  border-radius: 50%;
}
.fukidasi .chatting {
  width: 100%;
  text-align: left;
}
.says {
  display: inline-block;
  position: relative;
  margin: 0 0 0 50px;
  padding: 10px;
  max-width: 250px;
  border-radius: 12px;
  background: #edf1ee;
}
.says:after {
  content: "";
  display: inline-block;
  position: absolute;
  top: 3px;
  left: -19px;
  border: 8px solid transparent;
  border-right: 18px solid #edf1ee;
  -webkit-transform: rotate(35deg);
  transform: rotate(35deg);
}
.says p {
  margin: 0;
  padding: 0;
}
.mycomment {
  margin: 10px 0;
}
.mycomment p {
  display: inline-block;
  position: relative;
  margin: 0 10px 0 0;
  padding: 8px;
  max-width: 250px;
  border-radius: 12px;
  background: #30e852;
  font-size: 15px;
}
.mycomment p:after {
  content: "";
  position: absolute;
  top: 3px;
  right: -19px;
  border: 8px solid transparent;
  border-left: 18px solid #30e852;
  -webkit-transform: rotate(-35deg);
  transform: rotate(-35deg);
}
/************************************
** 送信フォーム
************************************/
#send-form{
  text-align:center;
  margin-bottom:200px;
}

gem 'jquery-rails'

$ bundle install

//= require rails-ujs
//= require activestorage
//= require turbolinks
//= require jquery #追記
//= require jquery_ujs #追記
//= require_tree .

$ rails g channel chat speak

module ApplicationCable
  class Connection < ActionCable::Connection::Base
  #channelでcurrent_userが使えるようにする
  identified_by :current_user

    def connect
      self.current_user = find_verified_user
    end

    protected
    def find_verified_user
      verified_user = User.find_by(id: env['warden'].user.id)
      return reject_unauthorized_connection unless verified_user
      verified_user
    end

    def session
      cookies.encrypted[Rails.application.config.session_options[:key]]
    end
  end
end

App.chat = App.cable.subscriptions.create("ChatChannel", {
  connected: function() {
    // Called when the subscription is ready for use on the server
  },
  disconnected: function() {
    // Called when the subscription has been terminated by the server
  },
  received: function(data) {
    //画面を開いているのがチャット送信者だった場合
    if (data["isCurrent_user"]==true){
      sentence=`<div class='mycomment'><p>${data["sentence"]}</p></div>`;
    }
    //画面を開いているのがチャット受信者だった場合
    else{
      sentence=`<div class='fukidasi'><div class='faceicon'>
      <img src='/assets/profile.png' alt='管理人'></div>
      <div class='chatting'><div class='says'><p>${data["sentence"]}</p>
      </div></div></div>`;
    }
    $('#chats').append(sentence);
  },
  speak: function(sentence) {
    current_user_id=$("#current_user_id").val();
    partner_id=$("#partner_id").val();
    return this.perform('speak',{sentence: sentence, current_user_id: current_user_id, partner_id: partner_id});
  }
});
$(function(){
  $("#send").on("click",function(e){
    sentence=$("#sentence").val();
    App.chat.speak(sentence);
    $("#sentence").val(""); //フォームを空に
    e.preventDefault();
  });
});

class ChatChannel < ApplicationCable::Channel
  def subscribed
    stream_from "chat_channel"
    stream_for current_user.id
  end

  def unsubscribed
    # Any cleanup needed when channel is unsubscribed
  end

  def speak(data)
    if data["sentence"]
      Chat.create!(
        user_id: data["current_user_id"].to_i,
        partner_id: data["partner_id"].to_i ,
        sentence: data["sentence"]
      )
      #画面を開いているのがチャット送信者だった場合
      ChatChannel.broadcast_to data["current_user_id"].to_i,
        sentence: data["sentence"],
        partner_id: data["partner_id"],
        isCurrent_user: true

      #画面を開いているのがチャット受信者だった場合
      ChatChannel.broadcast_to data["partner_id"].to_i,
        sentence: data["sentence"],
        partner_id: data["partner_id"],
        isCurrent_user: false
    end
  end
end