WebSocketとは?
WebSocketとは、WebサーバとWebブラウザの間で双方向通信できるようにする技術仕様。サーバ側から任意のタイミングで送信を開始でき、プッシュ型の情報配信アプリケーションを手軽に実装できる。
1.プロジェクトを作成する
公式:spring initializr
① ブラウザを開き、(https://start.spring.io/) を入力し、開く
② 下記を入力し、Dependenciesで下記を選択し、『GENERATE』ボタンを押す
Project: Maven
Language: Java
SpringBoot: 3.0.8
Group: com.alibou
Artifact: chat
Name : chat
Description: Demo project for Spring Boot chat application
Package name: com.alibou.chat
Dependencies
Spring Web
WebSocket
Lombok
2.バックエンドを実装する
① src/main/java/com/alibou/chatに configファイルとWebSocketConfig.javaを作成する。
package com.alibou.chat.config;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.messaging.SessionDisconnectEvent;
@Component
@RequiredArgsConstructor
@Slf4j
public class WebSocketEventLister {
@EventListener
public void handleWebSocketDisconnectListener(
SessionDisconnectEvent event
){
// TODO -- to be implemented
}
}
② src/main/java/com/alibou/chatに chatファイルとChatController.javaを作成する。
package com.alibou.chat.chat;
import org.springframework.messaging.handler.annotation.MessageMapping;
import org.springframework.messaging.handler.annotation.Payload;
import org.springframework.messaging.handler.annotation.SendTo;
import org.springframework.messaging.simp.SimpMessageHeaderAccessor;
import org.springframework.stereotype.Controller;
@Controller
public class ChatController {
@MessageMapping("/chat.sendMessage")
@SendTo("/topic/public")
public ChatMessage sendMessage(
@Payload ChatMessage chatMessage
) {
return chatMessage;
}
@MessageMapping("/chat.addUser")
@SendTo("/topic/public")
public ChatMessage addUser(
@Payload ChatMessage chatMessage,
SimpMessageHeaderAccessor headerAccessor
) {
//Add username in web socket session
headerAccessor.getSessionAttributes().put("username",chatMessage.getSender());
return chatMessage;
}
}
③ chatファイルにChatMessage.javaを作成する。
package com.alibou.websocket.chat;
import lombok.*;
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class ChatMessage {
private MessageType type;
private String content;
private String sender;
}
④ chatファイルにMessageType.javaを作成する。
package com.alibou.websocket.chat;
public enum MessageType {
CHAT,
JOIN,
LEAVE
}
⑤ src/main/java/com/alibou/chatに configファイルとWebSocket EventListener.javaを作成する。
package com.alibou.websocket.config;
import com.alibou.websocket.chat.ChatMessage;
import com.alibou.websocket.chat.MessageType;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.event.EventListener;
import org.springframework.messaging.simp.SimpMessageSendingOperations;
import org.springframework.messaging.simp.stomp.StompHeaderAccessor;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.messaging.SessionDisconnectEvent;
@Component
@Slf4j
@RequiredArgsConstructor
public class WebSocketEventListener {
private final SimpMessageSendingOperations messagingTemplate;
@EventListener
public void handleWebSocketDisconnectListener(SessionDisconnectEvent event) {
StompHeaderAccessor headerAccessor = StompHeaderAccessor.wrap(event.getMessage());
String username = (String) headerAccessor.getSessionAttributes().get("username");
if (username != null) {
log.info("user disconnected: {}", username);
var chatMessage = ChatMessage.builder()
.type(MessageType.LEAVE)
.sender(username)
.build();
messagingTemplate.convertAndSend("/topic/public", chatMessage);
}
}
}
3.フロントエンドを実装する
① src/main/resource/staticにindex.htmlを作成する
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0">
<title>Spring Boot WebSocket Chat Application</title>
<link rel="stylesheet" href="/css/main.css" />
</head>
<body>
<noscript>
<h2>Sorry! Your browser doesn't support Javascript</h2>
</noscript>
<div id="username-page">
<div class="username-page-container">
<h1 class="title">Type your username to enter the Chatroom</h1>
<form id="usernameForm" name="usernameForm">
<div class="form-group">
<input type="text" id="name" placeholder="Username" autocomplete="off" class="form-control" />
</div>
<div class="form-group">
<button type="submit" class="accent username-submit">Start Chatting</button>
</div>
</form>
</div>
</div>
<div id="chat-page" class="hidden">
<div class="chat-container">
<div class="chat-header">
<h2>Spring WebSocket Chat Demo - By Alibou</h2>
</div>
<div class="connecting">
Connecting...
</div>
<ul id="messageArea">
</ul>
<form id="messageForm" name="messageForm">
<div class="form-group">
<div class="input-group clearfix">
<input type="text" id="message" placeholder="Type a message..." autocomplete="off" class="form-control"/>
<button type="submit" class="primary">Send</button>
</div>
</div>
</form>
</div>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/sockjs-client/1.1.4/sockjs.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/stomp.js/2.3.3/stomp.min.js"></script>
<script src="/js/main.js"></script>
</body>
</html>
② src/main/resource/staticにcssファイルとmain.cssを作成する
* {
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
}
html,body {
height: 100%;
overflow: hidden;
}
body {
margin: 0;
padding: 0;
font-weight: 400;
font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
font-size: 1rem;
line-height: 1.58;
color: #333;
background-color: #f4f4f4;
height: 100%;
}
.clearfix:after {
display: block;
content: "";
clear: both;
}
.hidden {
display: none;
}
.form-control {
width: 100%;
min-height: 38px;
font-size: 15px;
border: 1px solid #c8c8c8;
}
.form-group {
margin-bottom: 15px;
}
input {
padding-left: 10px;
outline: none;
}
h1, h2, h3, h4, h5, h6 {
margin-top: 20px;
margin-bottom: 20px;
}
h1 {
font-size: 1.7em;
}
a {
color: #6db33f;
}
button {
box-shadow: none;
border: 1px solid transparent;
font-size: 14px;
outline: none;
line-height: 100%;
white-space: nowrap;
vertical-align: middle;
padding: 0.6rem 1rem;
border-radius: 2px;
transition: all 0.2s ease-in-out;
cursor: pointer;
min-height: 38px;
}
button.default {
background-color: #e8e8e8;
color: #333;
box-shadow: 0 2px 2px 0 rgba(0, 0, 0, 0.12);
}
button.primary {
background-color: #6db33f;
box-shadow: 0 2px 2px 0 rgba(0, 0, 0, 0.12);
color: #fff;
}
button.accent {
background-color: #6db33f;
box-shadow: 0 2px 2px 0 rgba(0, 0, 0, 0.12);
color: #fff;
}
#username-page {
text-align: center;
}
.username-page-container {
background: #fff;
box-shadow: 0 1px 11px rgba(0, 0, 0, 0.27);
border-radius: 2px;
width: 100%;
max-width: 500px;
display: inline-block;
margin-top: 42px;
vertical-align: middle;
position: relative;
padding: 35px 55px 35px;
min-height: 250px;
position: absolute;
top: 50%;
left: 0;
right: 0;
margin: 0 auto;
margin-top: -160px;
}
.username-page-container .username-submit {
margin-top: 10px;
}
#chat-page {
position: relative;
height: 100%;
}
.chat-container {
max-width: 700px;
margin-left: auto;
margin-right: auto;
background-color: #fff;
box-shadow: 0 1px 11px rgba(0, 0, 0, 0.27);
margin-top: 30px;
height: calc(100% - 60px);
max-height: 600px;
position: relative;
}
#chat-page ul {
list-style-type: none;
background-color: #FFF;
margin: 0;
overflow: auto;
overflow-y: scroll;
padding: 0 20px 0px 20px;
height: calc(100% - 150px);
}
#chat-page #messageForm {
padding: 20px;
}
#chat-page ul li {
line-height: 1.5rem;
padding: 10px 20px;
margin: 0;
border-bottom: 1px solid #f4f4f4;
}
#chat-page ul li p {
margin: 0;
}
#chat-page .event-message {
width: 100%;
text-align: center;
clear: both;
}
#chat-page .event-message p {
color: #777;
font-size: 14px;
word-wrap: break-word;
}
#chat-page .chat-message {
padding-left: 68px;
position: relative;
}
#chat-page .chat-message i {
position: absolute;
width: 42px;
height: 42px;
overflow: hidden;
left: 10px;
display: inline-block;
vertical-align: middle;
font-size: 18px;
line-height: 42px;
color: #fff;
text-align: center;
border-radius: 50%;
font-style: normal;
text-transform: uppercase;
}
#chat-page .chat-message span {
color: #333;
font-weight: 600;
}
#chat-page .chat-message p {
color: #43464b;
}
#messageForm .input-group input {
float: left;
width: calc(100% - 85px);
}
#messageForm .input-group button {
float: left;
width: 80px;
height: 38px;
margin-left: 5px;
}
.chat-header {
text-align: center;
padding: 15px;
border-bottom: 1px solid #ececec;
}
.chat-header h2 {
margin: 0;
font-weight: 500;
}
.connecting {
padding-top: 5px;
text-align: center;
color: #777;
position: absolute;
top: 65px;
width: 100%;
}
@media screen and (max-width: 730px) {
.chat-container {
margin-left: 10px;
margin-right: 10px;
margin-top: 10px;
}
}
@media screen and (max-width: 480px) {
.chat-container {
height: calc(100% - 30px);
}
.username-page-container {
width: auto;
margin-left: 15px;
margin-right: 15px;
padding: 25px;
}
#chat-page ul {
height: calc(100% - 120px);
}
#messageForm .input-group button {
width: 65px;
}
#messageForm .input-group input {
width: calc(100% - 70px);
}
.chat-header {
padding: 10px;
}
.connecting {
top: 60px;
}
.chat-header h2 {
font-size: 1.1em;
}
}
③ src/main/resource/static/jsファイルのmain.jsを編集する
'use strict';
var usernamePage = document.querySelector('#username-page');
var chatPage = document.querySelector('#chat-page');
var usernameForm = document.querySelector('#usernameForm');
var messageForm = document.querySelector('#messageForm');
var messageInput = document.querySelector('#message');
var messageArea = document.querySelector('#messageArea');
var connectingElement = document.querySelector('.connecting');
var stompClient = null;
var username = null;
var colors = [
'#2196F3', '#32c787', '#00BCD4', '#ff5652',
'#ffc107', '#ff85af', '#FF9800', '#39bbb0'
];
function connect(event) {
username = document.querySelector('#name').value.trim();
if(username) {
usernamePage.classList.add('hidden');
chatPage.classList.remove('hidden');
var socket = new SockJS('/ws');
stompClient = Stomp.over(socket);
stompClient.connect({}, onConnected, onError);
}
event.preventDefault();
}
function onConnected() {
// Subscribe to the Public Topic
stompClient.subscribe('/topic/public', onMessageReceived);
// Tell your username to the server
stompClient.send("/app/chat.addUser",
{},
JSON.stringify({sender: username, type: 'JOIN'})
)
connectingElement.classList.add('hidden');
}
function onError(error) {
connectingElement.textContent = 'Could not connect to WebSocket server. Please refresh this page to try again!';
connectingElement.style.color = 'red';
}
function sendMessage(event) {
var messageContent = messageInput.value.trim();
if(messageContent && stompClient) {
var chatMessage = {
sender: username,
content: messageInput.value,
type: 'CHAT'
};
stompClient.send("/app/chat.sendMessage", {}, JSON.stringify(chatMessage));
messageInput.value = '';
}
event.preventDefault();
}
function onMessageReceived(payload) {
var message = JSON.parse(payload.body);
var messageElement = document.createElement('li');
if(message.type === 'JOIN') {
messageElement.classList.add('event-message');
message.content = message.sender + ' joined!';
} else if (message.type === 'LEAVE') {
messageElement.classList.add('event-message');
message.content = message.sender + ' left!';
} else {
messageElement.classList.add('chat-message');
var avatarElement = document.createElement('i');
var avatarText = document.createTextNode(message.sender[0]);
avatarElement.appendChild(avatarText);
avatarElement.style['background-color'] = getAvatarColor(message.sender);
messageElement.appendChild(avatarElement);
var usernameElement = document.createElement('span');
var usernameText = document.createTextNode(message.sender);
usernameElement.appendChild(usernameText);
messageElement.appendChild(usernameElement);
}
var textElement = document.createElement('p');
var messageText = document.createTextNode(message.content);
textElement.appendChild(messageText);
messageElement.appendChild(textElement);
messageArea.appendChild(messageElement);
messageArea.scrollTop = messageArea.scrollHeight;
}
function getAvatarColor(messageSender) {
var hash = 0;
for (var i = 0; i < messageSender.length; i++) {
hash = 31 * hash + messageSender.charCodeAt(i);
}
var index = Math.abs(hash % colors.length);
return colors[index];
}
usernameForm.addEventListener('submit', connect, true)
messageForm.addEventListener('submit', sendMessage, true)
参考サイト
Spring boot & WebSockets: Build a Real-Time Chat App From Scratch
IT用語辞典