efw WebSocket Mode Function Example

Overview

The efw framework provides WebSocket mode support, implementing real-time communication, progress feedback, and broadcast functionality. This example demonstrates how to use WebSocket mode for efficient client-server communication, including progress display and real-time message broadcasting.

Core Files

WebSocket Mode Test Main Page: helloWsMode.jsp
Progress Test Function: helloWsMode_progress_test.js
Broadcast Start Function: helloWsMode_broadcast_start.js
Broadcast Stop Function: helloWsMode_broadcast_stop.js
Broadcast Receive Function: helloWsMode_broadcast_receive.js
Broadcast Stop Receive Function: helloWsMode_broadcast_bye.js

Feature Description

1. WebSocket Mode Advantages

Real-time Communication

Bidirectional Communication: Clients and servers can exchange messages in real-time
Low Latency: Messages arrive instantly without polling
Persistent Connection: Maintains long-lived connections, reducing connection establishment overhead

Progress Feedback

// Send progress update
efw.wsSend(new Result().progress("Processing...", 50));

// Complete progress
efw.wsSend(new Result().progress("Complete", 100, true));

2. Data Storage Scope

Storage Type	WebSocket Mode	Normal Mode	Application Scenarios
Session Storage	✅ Read/Write Support	✅ Read/Write Support	User session data, login status, etc.
Cookie Storage	✅ Read Support ❌ Write Invalid	✅ Read/Write Support	-
Context Storage	✅ Global Sharing	✅ Global Sharing	Broadcast messages, global configuration, shared data

Note: WebSocket connections cannot set HTTP Cookies

3. Broadcast Mechanism Principle

Broadcast Process

Broadcaster writes messages to Context
Receiver periodically reads messages from Context
WebSocket pushes messages to each client

Code Example

// Broadcaster sets content
context.set("broadcast_content", "Real-time message");

// Receiver reads content
var message = context.get("broadcast_content");

Application Scenarios

Long-running Task Processing

// Batch data processing progress
// Complex calculation task progress feedback

Real-time Applications

// Chat room message broadcasting
// Real-time data monitoring dashboard
// Multi-user collaborative editing notifications
// Real-time stock quote pushing

Task Monitoring

// Background task status monitoring
// System resource monitoring
// Real-time log viewing

Best Practices

1. Error Handling

The efw.wsSend function does not throw exceptions, only determines success through return values (considering possible client disconnections)

2. Resource Cleanup

// Clean up resources when stopping broadcast
context.set("broadcast_status", "false");
context.remove("broadcast_content");

// Clean up status when stopping reception
session.set("receive_status", "false");

3. Performance Optimization

// Control message frequency to avoid excessive WebSocket messages
java.lang.Thread.sleep(1000); // Update once per second

Considerations

1. Browser Compatibility

Modern browsers support WebSocket
Need to check browser support
Provide fallback solution (normal mode)

2. Connection Management

Automatic disconnection when browser closes
Framework automatically reconnects on network exceptions (up to 10 times)
Connection timeout: 20 seconds

3. Security

Recommended to use wss:// secure protocol
Security configuration methods are consistent with efw events

This example comprehensively demonstrates the WebSocket mode functionality of the efw framework, including advanced features such as real-time progress feedback and message broadcasting, suitable for modern web application scenarios requiring real-time communication.