add gorilla mux registration

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

templates/{{trimSuffix ".proto" .File.Name}}_micro_http.pb.go.tmpl

@@ -6,6 +6,7 @@ import (
 	"context"
   "fmt"
 
+	"github.com/gorilla/mux"
 	micro_client "github.com/unistack-org/micro/v3/client" 
 	micro_server "github.com/unistack-org/micro/v3/server"
 	micro_client_http "github.com/unistack-org/micro-client-http"
@@ -232,3 +233,31 @@ func (x *{{$ServiceName | lowerFirst}}{{.Name}}Stream) Recv() (*{{$reqMethod}},
 
 {{- end}}
 {{- end}}
+
+func Register(r *mux.Router, h interface{}, eps []*api.Endpoint) error {
+        v := reflect.ValueOf(h)
+
+        methods := v.NumMethod()
+        if methods < 1 {
+                return ErrInvalidHandler
+        }
+
+        for _, ep := range eps {
+                idx := strings.Index(ep.Name, ".")
+                if idx < 1 || len(ep.Name) <= idx {
+                        return fmt.Errorf("invalid api.Endpoint name: %s", ep.Name)
+                }
+                name := ep.Name[idx+1:]
+                m := v.MethodByName(name)
+                if !m.IsValid() || m.IsZero() {
+                        return fmt.Errorf("invalid handler, method %s not found", name)
+                }
+
+                rh, ok := m.Interface().(func(http.ResponseWriter, *http.Request))
+                if !ok {
+                        return fmt.Errorf("invalid handler: %#+v", m.Interface())
+                }
+                r.HandleFunc(ep.Path[0], rh).Methods(ep.Method...).Name(ep.Name)
+        }
+			return nil
+}