go - Serve a file when no route is matched with Gorilla? -

i'm using gorilla mux web server.

i define bunch of routes, if no route matched, want serve index.html file.

func (mgr *apimgr) instantiaterestrtr() *mux.router {     mgr.prestrtr = mux.newrouter().strictslash(true)     mgr.prestrtr.pathprefix("/api/").handler(http.stripprefix("/api/",         http.fileserver(http.dir(mgr.fullpath+"/docsui"))))      _, route := range mgr.restroutes {         var handler http.handler         handler = logger(route.handlerfunc, route.name)         mgr.prestrtr.methods(route.method)           .path(route.pattern)           .name(route.name)           .handler(handler)     }      // here want catch unmatched routes, , serve '/site/index.html` file.      // how can this?      return mgr.prestrtr } 

you don't need override 404 behaviour. use pathprefix catch-all route, adding after other routes.

func main() {     var entry string     var static string     var port string      flag.stringvar(&entry, "entry", "./index.html", "the entrypoint serve.")     flag.stringvar(&static, "static", ".", "the directory serve static files from.")     flag.stringvar(&port, "port", "8000", "the `port` listen on.")     flag.parse()      r := mux.newrouter()      // note: in larger application, we'd extract our route-building logic our handlers     // package, given coupling between them.      // it's important before catch-all route ("/")     api := r.pathprefix("/api/v1/").subrouter()     api.handlefunc("/users", getusershandler).methods("get")      // serve static assets directly.     r.pathprefix("/dist").handler(http.fileserver(http.dir(static)))      // catch-all: serve our javascript application's entry-point (index.html).     r.pathprefix("/").handlerfunc(indexhandler(entry))      srv := &http.server{         handler: handlers.logginghandler(os.stdout, r),         addr:    "127.0.0.1:" + port,         // practice: enforce timeouts servers create!         writetimeout: 15 * time.second,         readtimeout:  15 * time.second,     }      log.fatal(srv.listenandserve()) }  func indexhandler(entrypoint string) func(w http.responsewriter, r *http.request) {     fn := func(w http.responsewriter, r *http.request) {         http.servefile(w, r, entrypoint)     }      return http.handlerfunc(fn) } 

shameless plug: blogged on here: http://elithrar.github.io/article/vue-react-ember-server-golang/