Socket.IO v5 Go Client Examples

This repository contains example implementations of a Socket.IO v5 client written in Go, along with a mock server for testing.

Project Structure

• main.go - Go client example demonstrating Socket.IO v5 features
• mock-server/ - NestJS-based mock Socket.IO server for testing

Features

Go Client

• Socket.IO v5 client implementation using go.socket.io
• Custom high-speed JSON parser integration using go.socket.io-parser.jsoniter
• WebSocket transport configuration
• Event handling with acknowledgments and timeouts
• Context-based lifecycle management
• Structured logging with Zap

Mock Server

• Built with NestJS and Socket.IO
• Provides test endpoints for all client features
• 100% test coverage
• Docker support for easy deployment

Prerequisites

• Go 1.18 or higher
• Node.js v20 or higher (for mock server)
• Docker and Docker Compose (optional)

Quick Start

Using Docker Compose (Recommended)

# Clone the repository
git clone https://github.com/maldikhan/go.socket.io-examples.git
cd go.socket.io-examples

# Start both server and client
docker-compose up

# Or run them separately
docker-compose up mock-server  # Start server only
go run main.go                  # Run client locally

Manual Setup

1. Start the Mock Server

cd mock-server
yarn install
yarn start:dev

The server will start on port 3300.

2. Run the Go Client

# From the root directory
go mod download
go run main.go

Testing Scenarios

The mock server provides the following test endpoints:

1. Connection Test - Validates connection and authentication
2. Simple Echo (hi) - Basic request-response pattern
3. Async Operations (delay) - Tests timeouts and async handling
4. Load Testing (load) - High-frequency message handling
5. Data Validation (get_square, get_sum) - Complex data types and validation

Code Examples

Client Configuration

// Custom client with high-performance parser
client, err := socketio_v5_client.NewClient(
    socketio_v5_client.WithEngineIOClient(eioClient),
    socketio_v5_client.WithLogger(logger),
    socketio_v5_client.WithParser(socketio_v5_parser_default.NewParser(
        socketio_v5_parser_default.WithPayloadParser(
            socketio_v5_parser_default_jsoniter.NewPayloadParser()
        ),
    )),
)

Event Handling

// Simple emit with acknowledgment
client.Emit("hi", emit.WithAck(func(response string) {
    fmt.Println("Server said:", response)
}))

// Emit with timeout
client.Emit("delay", 1000, 
    emit.WithAck(func(response string) {...}),
    emit.WithTimeout(500*time.Millisecond, func() {...})
)

// Handle server events
client.On("result", func(operation string, result int) {
    fmt.Printf("%s = %d\n", operation, result)
})

Configuration

Client Configuration

By default, the client connects to http://127.0.0.1:3300. You can change this using:

1. Environment Variable:

export SOCKETIO_SERVER_URL="http://your-server:port/socket.io/"
go run main.go

2. Code Modification:

serverURL := "http://your-server:port/socket.io/"
eioClient, err := engineio_v4_client.NewClient(
    engineio_v4_client.WithRawURL(serverURL),
    // ... other options
)

Server Configuration

The mock server runs on port 3300 by default. See mock-server/README.md for detailed configuration options.

Development

Running Tests

# Test the mock server
cd mock-server
yarn test        # Unit tests
yarn test:e2e    # End-to-end tests
yarn test:cov    # Coverage report

Building Docker Images

# Build server image
docker build -t socketio-mock-server ./mock-server

# Or use docker-compose
docker-compose build

Dependencies

Go Client

• go.socket.io - Socket.IO v5 client library for Go
• go.socket.io-parser.jsoniter - High-performance JSON parser
• zap - Structured logging library

Mock Server

• NestJS - Node.js framework
• Socket.IO - Real-time bidirectional communication
• Jest - Testing framework

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.