Add env vars

Add support for user and pass connection.
Add support for specifying the HTTP port

main.go

@@ -1,19 +1,58 @@
 package main
 
 import (
+	"flag"
 	"fmt"
 	"io/ioutil"
 	"log"
 	"net/http"
+	"os"
 	"strings"
 	"time"
 
 	"github.com/nats-io/nats.go"
 )
 
+// printHelp outputs the usage information.
+func printHelp() {
+	fmt.Println("Usage: HTTP-to-NATS proxy server")
+	fmt.Println("\nThe following environment variables are supported:")
+	fmt.Println("    NATS_URL - NATS connection URL (default: nats://127.0.0.1:4222)")
+	fmt.Println("    NATS_USER - NATS username for authentication (optional)")
+	fmt.Println("    NATS_PASSWORD - NATS password for authentication (optional)")
+	fmt.Println("    HTTP_PORT - HTTP port to listen on (default: 8080)")
+}
+
 func main() {
-	// Connect to the NATS server
+	helpFlag := flag.Bool("help", false, "Display help information about available environment variables")
-	nc, err := nats.Connect(nats.DefaultURL)
+	flag.Parse()
+	if *helpFlag {
+		printHelp()
+		os.Exit(0)
+	}
+
+	// Read NATS connection info from environment variables
+	natsURL := os.Getenv("NATS_URL")
+	if natsURL == "" {
+		natsURL = nats.DefaultURL // defaults to "nats://127.0.0.1:4222"
+	}
+	natsUser := os.Getenv("NATS_USER")
+	natsPassword := os.Getenv("NATS_PASSWORD")
+
+	// Read HTTP port from environment variables
+	httpPort := os.Getenv("HTTP_PORT")
+	if httpPort == "" {
+		httpPort = "8080"
+	}
+
+	// Set up NATS connection options
+	opts := []nats.Option{}
+
+	if natsUser != "" && natsPassword != "" {
+		opts = append(opts, nats.UserInfo(natsUser, natsPassword))
+	}
+
+	nc, err := nats.Connect(natsURL, opts...)
 	if err != nil {
 		log.Fatal("Error connecting to NATS:", err)
 	}