Add WebTransport support to Engine.IO Java client #123
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- Add WebTransport transport implementation with HTTP/3 support - Add Jetty HTTP/3 client dependency (org.eclipse.jetty.http3:jetty-http3-client:12.1.1) - Update Java version from 1.7 to 17 for modern HTTP/3 support - Add comprehensive test suite with 17 test cases - Integrate WebTransport into Socket.java transport selection - Maintain full backward compatibility - Add WebTransport to default transport list: [polling, websocket, webtransport] Features: - Event-driven architecture (open, close, packet, error events) - Binary data support - Framing support - Graceful fallback behavior - Complete integration with existing Engine.IO infrastructure This implementation provides a foundation for WebTransport support and can be extended with full HTTP/3 functionality in future iterations.
added 2 commits
September 25, 2025 02:07
This commit adds comprehensive WebTransport support to the Engine.IO Java client,
enabling modern HTTP/3-based transport with automatic fallback to WebSocket and Polling.
### Key Features Added:
**WebTransport Transport Implementation:**
- New WebTransport.java transport using Jetty HTTP/3 client with Quiche backend
- Full HTTP/3 over QUIC support with proper ALPN negotiation
- WebTransport session management with bidirectional stream support
- Proper SSL/TLS configuration for self-signed certificates (development)
- Native library integration (jetty-quiche-native) for QUIC protocol support
**Automatic Transport Fallback:**
- Enhanced Socket.java with intelligent transport selection and fallback
- Fast timeout mechanism (2 seconds) for WebTransport attempts
- Seamless fallback: WebTransport → WebSocket → Polling
- Race condition fixes in transport event listeners during fallback
- Proper state management to prevent premature connection closure
**Transport Configuration:**
- Consistent transport-specific options via transportOptions map
- WebTransport hostname, port, secure, and path configuration
- SSL context factory integration for certificate handling
- Removed WebTransport from default transport list (opt-in only)
**Debugging and Logging:**
- Comprehensive error handling and connection timeout management
- Clean separation of transport-level vs connection-level errors
- Removed debug logging for production readiness
### Technical Implementation:
- **Dependencies**: Added jetty-quiche-native for native QUIC support
- **Protocol**: WebTransport over HTTP/3 with proper :protocol headers
- **Fallback**: 2-second timeout with immediate fallback to next transport
- **SSL**: Custom SSL context factory with trust-all option for development
- **Compatibility**: Maintains full backward compatibility with existing transports
### Usage:
```java
// Enable WebTransport with fallback
IO.Options options = IO.Options.builder()
.setTransports(new String[]{"webtransport", "websocket", "polling"})
.build();
// Advanced WebTransport configuration
Transport.Options webTransportOptions = new Transport.Options();
webTransportOptions.hostname = "127.0.0.1";
webTransportOptions.port = 3000;
options.transportOptions.put("webtransport", webTransportOptions);
```
This implementation provides a robust, production-ready WebTransport solution
that gracefully falls back to traditional transports when WebTransport is
unavailable, ensuring maximum compatibility and reliability.
Fixes: WebTransport support for modern HTTP/3 servers
Closes: Transport fallback reliability issues
This commit fixes the transport fallback error handling to match the standard
Engine.IO client behavior. Previously, we were emitting a custom
'all_transports_failed' event, but the standard behavior is to emit
Socket.EVENT_ERROR with 'No transports available' message.
Changes:
- Changed emit('all_transports_failed') to emit(Socket.EVENT_ERROR)
- Updated error message to 'No transports available' (standard message)
- Set socket readyState to CLOSED when all transports fail
- Ensures compatibility with existing Engine.IO client applications
This matches the behavior expected by Socket.IO applications and maintains
consistency with the JavaScript Engine.IO client implementation.
Our unified approach in tryNextTransport() is actually cleaner than the
original implementation which had duplicate error handling logic in both
open() and fallback mechanisms.
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Add WebTransport Support to Socket.IO Java Client
This PR adds comprehensive WebTransport support to the Socket.IO Java client ecosystem, enabling modern HTTP/3-based real-time communication with automatic fallback to traditional transports.
🚀 Overview
WebTransport is a modern transport protocol based on HTTP/3 and QUIC that provides improved performance, reduced latency, and better handling of network conditions compared to traditional WebSocket connections.
This implementation provides production-ready WebTransport support with seamless fallback behavior.
📦 Changes Summary
Engine.IO Client (
engine.io-client-java)jetty-quiche-nativedependency for native QUIC protocol supporttryNextTransport()methodSocket.EVENT_ERRORemission when all transports failSocket.IO Client (
socket.io-client-java)🔧 Technical Implementation
Dependencies Added
jetty-quiche-nativeKey Features
📋 Usage
🧪 Testing
🔄 Migration Guide
Before (Complex, Inconsistent)
After (Simple, Consistent)
✅ Compatibility
Socket.EVENT_ERRORemission🎯 Benefits
🏗️ Architecture Improvements
tryNextTransport()Socket.EVENT_ERRORemissionreadyStatehandling throughout transport lifecycle📌 Notes
✅ This implementation provides a robust, production-ready WebTransport solution that gracefully falls back to traditional transports when WebTransport is unavailable, ensuring maximum compatibility and reliability for Socket.IO Java applications.