CMPS4191-Test2

Simple Go WebSocket playground that serves a static test page and exposes a JSON-aware echo service for experimenting with WebSocket message handling patterns.

Features

• Serves static assets from web/ and exposes /test and /ws endpoints.
• Upgrades HTTP GET requests on /ws to WebSocket connections using Gorilla WebSocket with strict origin checks for ws://localhost:4000.
• Echoes plain text messages with a running counter, supports UPPER: and REVERSE: directives, and tracks message totals atomically.
• Accepts JSON commands for basic math operations (add, subtract, multiply, divide) and responds with structured JSON payloads.
• Maintains healthy connections with ping/pong heartbeats, read deadlines, and graceful close handling.

Prerequisites

• Go 1.25 or newer (go env GOVERSION should report at least go1.25).
• Make (optional) if you want the convenience targets in the provided Makefile.

Setup

1. Clone the repository and enter the project directory.

   git clone https://github.com/alexdev404/ws-main.git
   cd ws-main

2. Download Go module dependencies.

   go mod download

Running the server

• Directly via Go:

  go run ./cmd/web

• Or with the included Make target:

  make run/web

The server listens on http://localhost:4000. Static files in web/ are served from the root; web/test.html is a ready-to-use client for trying the WebSocket API.

Using the WebSocket endpoint

1. Start the server.
2. Open http://localhost:4000/test.html in a browser. The page establishes a WebSocket connection to ws://localhost:4000/ws.
3. Send messages using the input field:
   • Plain text (hello) echoes back as [Msg #N] hello where N is the global counter.
   • Prefix with UPPER: to force uppercase (UPPER:hello → [Msg #N] HELLO).
   • Prefix with REVERSE: to reverse the remaining text (REVERSE:abc → [Msg #N] cba).
   • Send JSON for math commands, e.g. {"command":"add","a":3,"b":4}. The server responds with JSON: {"result":7,"command":"add"}. Division by zero and unknown commands return an error string.
4. Connections are limited to the allowed origin list; adjust allowedOrigins in internal/ws/handler.go if you need to serve from a different host.

Running tests

Execute the Go test suite:

go test ./...

Project structure

cmd/web/          # Entry point for the HTTP/WebSocket server
internal/ws/      # WebSocket handler, message processing helpers
web/              # Static assets including the WebSocket demo page
go.mod            # Module definition and dependencies
Makefile          # Convenience target for running the server

Troubleshooting

• Origin blocked: Ensure you access the app through http://localhost:4000; otherwise update the allowedOrigins slice.
• Port in use: Stop other services on port 4000 or change the port in cmd/web/main.go and rebuild.