route/vendor/github.com/grpc-ecosystem/grpc-gateway/examples/main.go

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2017-09-30 16:47:47 +00:00
package main
import (
"flag"
"net/http"
"path"
"strings"
"github.com/golang/glog"
"github.com/grpc-ecosystem/grpc-gateway/examples/examplepb"
"github.com/grpc-ecosystem/grpc-gateway/runtime"
"golang.org/x/net/context"
"google.golang.org/grpc"
)
var (
echoEndpoint = flag.String("echo_endpoint", "localhost:9090", "endpoint of EchoService")
abeEndpoint = flag.String("more_endpoint", "localhost:9090", "endpoint of ABitOfEverythingService")
flowEndpoint = flag.String("flow_endpoint", "localhost:9090", "endpoint of FlowCombination")
swaggerDir = flag.String("swagger_dir", "examples/examplepb", "path to the directory which contains swagger definitions")
)
// newGateway returns a new gateway server which translates HTTP into gRPC.
func newGateway(ctx context.Context, opts ...runtime.ServeMuxOption) (http.Handler, error) {
mux := runtime.NewServeMux(opts...)
dialOpts := []grpc.DialOption{grpc.WithInsecure()}
err := examplepb.RegisterEchoServiceHandlerFromEndpoint(ctx, mux, *echoEndpoint, dialOpts)
if err != nil {
return nil, err
}
err = examplepb.RegisterStreamServiceHandlerFromEndpoint(ctx, mux, *abeEndpoint, dialOpts)
if err != nil {
return nil, err
}
err = examplepb.RegisterABitOfEverythingServiceHandlerFromEndpoint(ctx, mux, *abeEndpoint, dialOpts)
if err != nil {
return nil, err
}
err = examplepb.RegisterFlowCombinationHandlerFromEndpoint(ctx, mux, *flowEndpoint, dialOpts)
if err != nil {
return nil, err
}
return mux, nil
}
func serveSwagger(w http.ResponseWriter, r *http.Request) {
if !strings.HasSuffix(r.URL.Path, ".swagger.json") {
glog.Errorf("Not Found: %s", r.URL.Path)
http.NotFound(w, r)
return
}
glog.Infof("Serving %s", r.URL.Path)
p := strings.TrimPrefix(r.URL.Path, "/swagger/")
p = path.Join(*swaggerDir, p)
http.ServeFile(w, r, p)
}
// allowCORS allows Cross Origin Resoruce Sharing from any origin.
// Don't do this without consideration in production systems.
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
}
// Run starts a HTTP server and blocks forever if successful.
func Run(address string, opts ...runtime.ServeMuxOption) error {
ctx := context.Background()
ctx, cancel := context.WithCancel(ctx)
defer cancel()
mux := http.NewServeMux()
mux.HandleFunc("/swagger/", serveSwagger)
gw, err := newGateway(ctx, opts...)
if err != nil {
return err
}
mux.Handle("/", gw)
return http.ListenAndServe(address, allowCORS(mux))
}
func main() {
flag.Parse()
defer glog.Flush()
if err := Run(":8080"); err != nil {
glog.Fatal(err)
}
}