overflow_service_websocket/main.go

package main

import (
	"log"
	"net/http"
	"os"
	"path/filepath"

	"git.loafle.net/overflow/overflow_service_websocket/config"
	"git.loafle.net/overflow/overflow_service_websocket/server"
	"strings"
	"github.com/golang/glog"
)

const (
	version = "1.0.0"
	website = "https://www.overflow.cloud"
	banner  = `

 ██████╗ ██╗   ██╗███████╗██████╗ ███████╗██╗      ██████╗ ██╗    ██╗
██╔═══██╗██║   ██║██╔════╝██╔══██╗██╔════╝██║     ██╔═══██╗██║    ██║
██║   ██║██║   ██║█████╗  ██████╔╝█████╗  ██║     ██║   ██║██║ █╗ ██║
██║   ██║╚██╗ ██╔╝██╔══╝  ██╔══██╗██╔══╝  ██║     ██║   ██║██║███╗██║
╚██████╔╝ ╚████╔╝ ███████╗██║  ██║██║     ███████╗╚██████╔╝╚███╔███╔╝
 ╚═════╝   ╚═══╝  ╚══════╝╚═╝  ╚═╝╚═╝     ╚══════╝ ╚═════╝  ╚══╝╚══╝ 
                                                                     
`
)

func printVersion() {
	log.Printf("Version: %s\n", version)
	log.Printf("Url: %s\n", website)
	log.Println(banner)
}

func main() {

	// Initialize config
	config := loadConfig()

	addr := config.Server.Addr
	useTLS := config.Server.Tls
	sConfig := server.NewOptions(&config.Websocket)
	// Print banner
	printVersion()

	// Config TLS

	ws := server.New(sConfig)

	ws.OnConnection(func(c server.Client) {
		log.Println("Client have been connected")
		c.OnDisconnect(func(c server.Client) {
			log.Println("Client have been disconnected")
		})
	})

	http.Handle("/rpc", allowCORS(ws.HTTPHandler()))
	log.Printf("Address: %s, UseTLS: %t", addr, useTLS)

	if err := http.ListenAndServe(addr, nil); err != nil {
		log.Fatal(err)
	}
}

//https://github.com/grpc-ecosystem/grpc-gateway/blob/master/examples/main.go

func allowCORS(h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if origin := r.Header.Get("Origin"); origin != "" {
			w.Header().Set("Access-Control-Allow-Origin", origin)
			if r.Method == "OPTIONS" && r.Header.Get("Access-Control-Request-Method") != "" {
				preflightHandler(w, r)
				return
			}
		}
		h.ServeHTTP(w, r)
	})
}

func preflightHandler(w http.ResponseWriter, r *http.Request) {
	headers := []string{"Content-Type", "Accept"}
	w.Header().Set("Access-Control-Allow-Headers", strings.Join(headers, ","))
	methods := []string{"GET", "HEAD", "POST", "PUT", "DELETE"}
	w.Header().Set("Access-Control-Allow-Methods", strings.Join(methods, ","))
	glog.Infof("preflight request for %s", r.URL.Path)
	return
}

func loadConfig() *config.Config {
	os.Chdir("./")
	wd, _ := os.Getwd()
	path := filepath.Join(wd, "config.json")

	err := config.InitConfig(path)
	if nil != err {
		log.Fatalln("Config error")
	}
	return config.GetConfig()
}