WEBSOCKET-DEMO

This is a prototype project demonstrated how to build a web socket project using Spring Boot and Vue.

In this project, there is a ticker service emitting message to the Vue client every one second. And in the Vue UI client, there is an input and button to send message back to the server and the server will log that message to the console.

How to build and run

Build with gradle:

> ./gradlew clean build

You can also run using spring-boot plugin:

> ./gradlew bootRun

This probject will build into a war file, you can deploy that war file into your app server, or you can also just run that war file using java -jar build/libs/websocket-demo-0.0.1-SNAPSHOT.war.

To build the Vue UI, make sure npm is installed on your system and

> cd src/main/frontend
> npm install && npm run build

Please refer to the UI's README file.

Then UI will be built into src/main/resources/static. The server will host the ui static files.

Note that you don't have to build the UI, it's pre-built and included in the source.

After all builds are successful, open http://localhost:8080 in your web browser.

How to debug Vue

If you want to debug the UI, you can cd into the frontend folder and just run the dev build like this:

> cd src/main/frontend
> npm run dev

Remember to run npm install beforehand.

What's to learn?

For Spring's WebSocket's support:

• First, to enable websocket in Spring Boot, you should include spring-boot-starter-websocket in your dependency.
• Second, config a message borker like this one WebSocketConfig.java.
• The @EnableWebSocketMessageBroker is required, Spring's auto config won't auto-config that for you.
• To receive message from client, use @MessageMapping annotation on controllers, like @RequestMapping does.
• To send message to client, use @SendTo annotation on controllers, like @ResponseBody does.
• Note that if you are sending message on threads other than controllers, @SendTo won't work (Not 100% sure, I'm sure it doesn't work on @Scheduled methods).
• To send message from things other than controllers, SimpMessagingTemplate is required. Refer to TickService.java for more details.
• Spring Websocket support is based on SockJS and Stomp.
• Please refer to 26. WebSocket Support official document for more details. (It's a very long doc, please be patient.)
• And there's a quick guide in Spring guides called Using WebSocket to build an interactive web application to let you get started very fast.

For Vue's:

• I couldn't find a good SockJS and Stomp plugin for Vue, if you know one please let me know thanks.
• So to communicate with Spring's websocket, sockjs-client and webstomp-client are used.
• WebSocket is connected when the Home component is mounted, please refer to Home.vue for more details.
• The code about SockJS and Stomp was refered from Create a browser client section from Spring's guide, but the origin one is using JQuery.

TODOs

• Change WebSocket messages into json instead of string.
• Refactor WebSocket in Home.vue into a service utilizing Promise or a Vue plugin (Don't know how to write Vue plugin).
• Refactor into meanful demo like a web chat app or message notification app.
• Integrate npm build process into gradle build.
• Separate frontend and backend into 2 isolated projects???