Add a reflectionless fast path for common signature func(context.Cont…

…ext, *http.Request) HttpResponse

wrap.go

@@ -86,9 +86,6 @@ func WithErrorHandler(f ErrorHandler) WrapOption {
 // Wrap takes a request handler function and returns a http.HandlerFunc for use with net/http.
 // The given handler is expected to take arguments like context.Context, *http.Request and return a convreq.HttpResponse or an error.
 func Wrap(f interface{}, opts ...WrapOption) http.HandlerFunc {
-	t := reflect.TypeOf(f)
-	v := reflect.ValueOf(f)
-
 	wo := wrapOptions{
 		extractors: map[reflect.Type]extractor{},
 		handlers:   map[reflect.Type]reflect.Value{},
@@ -103,6 +100,28 @@ func Wrap(f interface{}, opts ...WrapOption) http.HandlerFunc {
 		o(&wo)
 	}
 
+	if fun, ok := f.(func(context.Context, *http.Request) HttpResponse); ok {
+		// Fast path without reflection for this common signature.
+		return func(w http.ResponseWriter, r *http.Request) {
+			ctx := r.Context()
+			if len(wo.contextWrappers) > 0 {
+				var cancel func()
+				for _, cw := range wo.contextWrappers {
+					ctx, cancel = cw(ctx)
+					if cancel != nil {
+						defer cancel()
+					}
+				}
+				r = r.WithContext(ctx)
+			}
+			hr := fun(ctx, r)
+			internal.DoRespond(w, r, hr)
+		}
+	}
+
+	t := reflect.TypeOf(f)
+	v := reflect.ValueOf(f)
+
 	if t.Kind() != reflect.Func {
 		panic(fmt.Errorf("convreq: %s: not a function", v.String()))
 	}