websocket-with-springboot

This is a simple example of how to deal with websocket with spring boot.

There are various Implementation can be found in this repo in a different branch:

• main branch - has the implementation of Simple WebSocket connected to a SPA.

• sockjs branch - has the implementation of Simple WebSocket with SockJs fallback connected to a SPA.

• stomp branch - has the implementation of STOMP over WebSocket connected to a SPA.

Documentation

Websocket with Spring Boot MVC

Websocket with Spring Boot WebFlux

WebSocket

• WebSocket is a communication protocol that provides a full-duplex channel over a single, long-lived TCP connection.
• It allows a client (typically a web browser) and a server to exchange messages in real time with minimal overhead, making it ideal for interactive applications like chat apps, live notifications, gaming, and financial data feeds.

HTTP vs WebSocket

Feature	HTTP	WebSocket
Nature	Request-Response (unidirectional)	Full-duplex (bidirectional)
Connection	Short-lived; one request per connection	Persistent; single connection for multiple messages
Latency	High (requires new connection setup)	Low (no need to re-establish connection)
Overhead	Higher (repeated headers per request)	Lower (single connection with minimal headers)
Use Case	Static or less interactive content	Real-time, interactive applications

Websocket protocol does not / might not work with all proxies, firewalls, and antivirus software. So, it is always good to have a fallback mechanism (like SockJs) or an alternative like long poling.

SockJs

• SockJS is a JavaScript library that provides a WebSocket-like API but with automatic fallback mechanisms for environments where WebSockets are not supported.
• It ensures real-time communication between clients and servers, even when WebSockets are blocked by firewalls, proxies, or outdated browsers.
• Acts as a WebSocket wrapper, providing a consistent API.
• If WebSockets aren’t available, it automatically switches to alternative transport methods like:
  • XHR Streaming
  • XHR Polling
  • JSONP Polling
  • EventSource (for servers supporting Server-Sent Events)
  • Helps establish a persistent connection across various network conditions.
  • SockJs JavaScript Library.

---

STOMP

• STOMP = Simple Text Oriented Messaging Protocol , was originally created for scripting languages (such as Ruby, Python, and Perl) to connect to enterprise message brokers.
• STOMP is a lightweight, simple text-based protocol designed for communication between clients and message brokers like RabbitMQ, ActiveMQ, etc.
• STOMP can be used over any reliable two-way streaming network protocol, such as TCP and WebSocket.
• Although STOMP is a text-oriented protocol, message payloads can be either text or binary.
  • STOMP over WebSockets provides several advantages, particularly for real-time, message-driven applications like:
    • Structured Messaging Over WebSockets (STOMP frames)

      COMMAND [SEND, SUBSCRIBE, SEND, MESSAGE, etc.]
      header1:value1
      header2:value2
      
      Body^@

    • Pub-Sub (Publish-Subscribe) Model Support
    • Integration with Message Brokers (RabbitMQ, ActiveMQ, etc.)
    • Better Decoupling Between Frontend & Backend
    • Acknowledgment & Message Delivery Guarantees
    • When Should You Use WebSocket with STOMP?
      • Real-time chat applications
      • Live notifications
      • Multiplayer games
      • Financial data feeds
      • Collaborative editing tools
      • IoT (Internet of Things) applications

Benefits by Using STOMP over websocker/SockJs with springboot

• No need to invent a custom messaging protocol and message format.

• STOMP clients, including a Java client in the Spring Framework, are available.

• You can (optionally) use message brokers (such as RabbitMQ, ActiveMQ, and others) to manage subscriptions and broadcast messages.

• Application logic can be organized in any number of @Controller instances and messages can be routed to them based on the STOMP destination header versus handling raw WebSocket messages with a single WebSocketHandler for a given connection.

• You can use Spring Security to secure messages based on STOMP destinations and message types.

Implementation

MVC

We need to have these dependency in our pom.xml file.

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-websocket</artifactId>
    </dependency>

1.) Need a Handler (WebSocketHandler, TextWebSocketHandler or BinaryWebSocketHandler for WebSocket session) 2.) WebSocketConfiguration to register WebSocketHandler 3.) Custom HandshakeInterceptor to add attributes to WebSocketSession

Extend this with SockJs to support fallback options for browsers that don't support WebSocket.

WebFlux

We need to have these dependency in our pom.xml file.

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-webflux</artifactId>
    </dependency>