main.go

main.go

package main

import (
"context" // Use "golang.org/x/net/context" for Golang version <= 1.6
"flag"
"net/http"
"github.com/golang/glog"
"github.com/grpc-ecosystem/grpc-gateway/runtime"
"google.golang.org/grpc"

	gw "showme.codes/ossl/ossl" // Update
	"strings"
)

var (
	// command-line options:
	// gRPC server endpoint
	grpcServerEndpoint = flag.String("grpc-server-endpoint", "localhost:8187", "gRPC server endpoint")
)
func allowCORS(h http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-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-Origin", "*")
	w.Header().Set("Access-Control-Allow-Headers", strings.Join(headers, ","))
	methods := []string{"GET", "HEAD", "POST", "PUT", "DELETE","OPTIONS"}
	w.Header().Set("Access-Control-Allow-Methods", strings.Join(methods, ","))
	glog.Infof("preflight request for %s", r.URL.Path)
	return
}
func run() error {
	ctx := context.Background()
	ctx, cancel := context.WithCancel(ctx)
	defer cancel()

	// Register gRPC server endpoint
	// Note: Make sure the gRPC server is running properly and accessible
	mux := runtime.NewServeMux()
	opts := []grpc.DialOption{grpc.WithInsecure()}
	err := gw.RegisterCategoryServiceHandlerFromEndpoint(ctx, mux, *grpcServerEndpoint, opts)
	if err != nil {
		return err
	}

	// Start HTTP server (and proxy calls to gRPC server endpoint)
	return http.ListenAndServe(":8286", allowCORS(mux))
}

func main() {
	flag.Parse()
	defer glog.Flush()

	if err := run(); err != nil {
		glog.Fatal(err)
	}
}