perf: cut allocations

bench_test.go

@@ -21,6 +21,38 @@ func BenchmarkMux(b *testing.B) {
 	}
 }
 
+func BenchmarkMuxSimple(b *testing.B) {
+	router := new(Router)
+	handler := func(w http.ResponseWriter, r *http.Request) {}
+	router.HandleFunc("/status", handler)
+
+	testCases := []struct {
+		name                 string
+		omitRouteFromContext bool
+	}{
+		{
+			name:                 "default",
+			omitRouteFromContext: false,
+		},
+		{
+			name:                 "omit route from ctx",
+			omitRouteFromContext: true,
+		},
+	}
+	for _, tc := range testCases {
+		b.Run(tc.name, func(b *testing.B) {
+			router.OmitRouteFromContext(tc.omitRouteFromContext)
+
+			request, _ := http.NewRequest("GET", "/status", nil)
+			b.ReportAllocs()
+			b.ResetTimer()
+			for i := 0; i < b.N; i++ {
+				router.ServeHTTP(nil, request)
+			}
+		})
+	}
+}
+
 func BenchmarkMuxAlternativeInRegexp(b *testing.B) {
 	router := new(Router)
 	handler := func(w http.ResponseWriter, r *http.Request) {}

mux.go

@@ -9,6 +9,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"net/url"
 	"path"
 	"regexp"
 )
@@ -84,6 +85,9 @@ type routeConf struct {
 	// will not redirect
 	skipClean bool
 
+	// If true, the http.Request context will not contain the Route.
+	omitRouteFromContext bool
+
 	// Manager for the variables from host and path.
 	regexp routeRegexpGroup
 
@@ -180,15 +184,7 @@ func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 		}
 		// Clean path to canonical form and redirect.
 		if p := cleanPath(path); p != path {
-
-			// Added 3 lines (Philip Schlump) - It was dropping the query string and #whatever from query.
-			// This matches with fix in go 1.2 r.c. 4 for same problem.  Go Issue:
-			// http://code.google.com/p/go/issues/detail?id=5252
-			url := *req.URL
-			url.Path = p
-			p = url.String()
-
-			w.Header().Set("Location", p)
+			w.Header().Set("Location", replaceURLPath(req.URL, p))
 			w.WriteHeader(http.StatusMovedPermanently)
 			return
 		}
@@ -197,8 +193,15 @@ func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	var handler http.Handler
 	if r.Match(req, &match) {
 		handler = match.Handler
-		req = requestWithVars(req, match.Vars)
-		req = requestWithRoute(req, match.Route)
+		if handler != nil {
+			// Populate context for custom handlers
+			if r.omitRouteFromContext {
+				// Only populate the match vars (if any) into the context.
+				req = requestWithVars(req, match.Vars)
+			} else {
+				req = requestWithRouteAndVars(req, match.Route, match.Vars)
+			}
+		}
 	}
 
 	if handler == nil && match.MatchErr == ErrMethodMismatch {
@@ -260,6 +263,16 @@ func (r *Router) SkipClean(value bool) *Router {
 	return r
 }
 
+// OmitRouteFromContext defines the behavior of omitting the Route from the
+//
+//	http.Request context.
+//
+// CurrentRoute will yield nil with this option.
+func (r *Router) OmitRouteFromContext(value bool) *Router {
+	r.omitRouteFromContext = value
+	return r
+}
+
 // UseEncodedPath tells the router to match the encoded original path
 // to the routes.
 // For eg. "/path/foo%2Fbar/to" will match the path "/path/{var}/to".
@@ -445,13 +458,25 @@ func CurrentRoute(r *http.Request) *Route {
 	return nil
 }
 
+// requestWithRouteAndVars adds the matched vars to the request ctx.
+// It shortcuts the operation when the vars are empty.
 func requestWithVars(r *http.Request, vars map[string]string) *http.Request {
+	if len(vars) == 0 {
+		return r
+	}
 	ctx := context.WithValue(r.Context(), varsKey, vars)
 	return r.WithContext(ctx)
 }
 
-func requestWithRoute(r *http.Request, route *Route) *http.Request {
+// requestWithRouteAndVars adds the matched route and vars to the request ctx.
+// It saves extra allocations in cloning the request once and skipping the
+//
+//	population of empty vars, which in turn mux.Vars can handle gracefully.
+func requestWithRouteAndVars(r *http.Request, route *Route, vars map[string]string) *http.Request {
 	ctx := context.WithValue(r.Context(), routeKey, route)
+	if len(vars) > 0 {
+		ctx = context.WithValue(ctx, varsKey, vars)
+	}
 	return r.WithContext(ctx)
 }
 
@@ -478,6 +503,14 @@ func cleanPath(p string) string {
 	return np
 }
 
+// replaceURLPath prints an url.URL with a different path.
+func replaceURLPath(u *url.URL, p string) string {
+	// Operate on a copy of the request url.
+	u2 := *u
+	u2.Path = p
+	return u2.String()
+}
+
 // uniqueVars returns an error if two slices contain duplicated strings.
 func uniqueVars(s1, s2 []string) error {
 	for _, v1 := range s1 {