code: func NewHandler(store mock.GlobalStorer, corsOrigins []string) (handler http.Handler) {
  	mux := http.NewServeMux()
  	mux.Handle("/api/has-key/", newHasKeyHandler(store))
  	mux.Handle("/api/keys", newKeysHandler(store))
  	mux.Handle("/api/nodes", newNodesHandler(store))
  	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
  		jsonStatusResponse(w, http.StatusNotFound)
  	})
  	handler = noCacheHandler(mux)
  	if corsOrigins != nil {
  		handler = cors.New(cors.Options{
  			AllowedOrigins: corsOrigins,
  			AllowedMethods: []string{"GET"},
  			MaxAge:         600,
  		}).Handler(handler)
  	}
  	return handler
  }
docs: // NewHandler constructs an http.Handler with router
  // that servers requests required by chunk explorer.
  //
  //   /api/has-key/{node}/{key}
  //   /api/keys?start={key}&node={node}&limit={int[0..1000]}
  //   /api/nodes?start={node}&key={key}&limit={int[0..1000]}
  //
  // Data from global store will be served and appropriate
  // CORS headers will be sent if allowed origins are provided.