feat: run filters earlier to prevent unnecessary processing

Author: samber

example/example.go

@@ -7,6 +7,8 @@ import (
 
 	"log/slog"
 
+	"log"
+
 	slogformatter "github.com/samber/slog-formatter"
 	sloghttp "github.com/samber/slog-http"
 )
@@ -52,7 +54,10 @@ func main() {
 	handler = sloghttp.New(logger.WithGroup("http"))(handler)
 
 	// Start server
-	http.ListenAndServe(":4242", handler)
+	err := http.ListenAndServe(":4242", handler)
+	if err != nil {
+		log.Fatal(err)
+	}
 
 	// output:
 	// time=2023-04-10T14:00:00Z level=INFO msg="Success" env=production http.status=200 http.method=GET http.path=/ http.ip=::1 http.latency=25.958µs http.user-agent=curl/7.77.0 http.time=2023-04-10T14:00:00Z http.request-id=229c7fc8-64f5-4467-bc4a-940700503b0d

example/go.mod

@@ -11,9 +11,9 @@ require (
 
 require (
 	github.com/google/uuid v1.6.0 // indirect
-	github.com/samber/lo v1.38.1 // indirect
+	github.com/samber/lo v1.47.0 // indirect
 	github.com/samber/slog-multi v1.0.0 // indirect
 	go.opentelemetry.io/otel v1.19.0 // indirect
 	go.opentelemetry.io/otel/trace v1.19.0 // indirect
-	golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1 // indirect
+	golang.org/x/text v0.16.0 // indirect
 )

example/go.sum

@@ -6,8 +6,8 @@ github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/samber/lo v1.38.1 h1:j2XEAqXKb09Am4ebOg31SpvzUTTs6EN3VfgeLUhPdXM=
-github.com/samber/lo v1.38.1/go.mod h1:+m/ZKRl6ClXCE2Lgf3MsQlWfh4bn1bz6CXEOxnEXnEA=
+github.com/samber/lo v1.47.0 h1:z7RynLwP5nbyRscyvcD043DWYoOcYRv3mV8lBeqOCLc=
+github.com/samber/lo v1.47.0/go.mod h1:RmDH9Ct32Qy3gduHQuKJ3gW1fMHAnE/fAzQuf6He5cU=
 github.com/samber/slog-formatter v1.0.0 h1:ULxHV+jNqi6aFP8xtzGHl2ejFRMl2+jI2UhCpgoXTDA=
 github.com/samber/slog-formatter v1.0.0/go.mod h1:c7pRfwhCfZQNzJz+XirmTveElxXln7M0Y8Pq781uxlo=
 github.com/samber/slog-multi v1.0.0 h1:snvP/P5GLQ8TQh5WSqdRaxDANW8AAA3egwEoytLsqvc=
@@ -18,7 +18,7 @@ go.opentelemetry.io/otel v1.19.0 h1:MuS/TNf4/j4IXsZuJegVzI1cwut7Qc00344rgH7p8bs=
 go.opentelemetry.io/otel v1.19.0/go.mod h1:i0QyjOq3UPoTzff0PJB2N66fb4S0+rSbSB15/oyH9fY=
 go.opentelemetry.io/otel/trace v1.19.0 h1:DFVQmlVbfVeOuBRrwdtaehRrWiL1JoVs9CPIQ1Dzxpg=
 go.opentelemetry.io/otel/trace v1.19.0/go.mod h1:mfaSyvGyEJEI0nyV2I4qhNQnbBOUUmYZpYojqMnX2vo=
-golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1 h1:k/i9J1pBpvlfR+9QsetwPyERsqu1GIbi967PQMq3Ivc=
-golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1/go.mod h1:V1LtkGg67GoY2N1AnLN78QLrzxkLyJw7RJb1gzOOz9w=
+golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
+golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

middleware.go

@@ -131,6 +131,13 @@ func NewWithConfig(logger *slog.Logger, config Config) func(http.Handler) http.H
 			bw := newBodyWriter(w, ResponseBodyMaxSize, config.WithResponseBody)
 
 			defer func() {
+				// Pass thru filters and skip early the code below, to prevent unnecessary processing.
+				for _, filter := range config.Filters {
+					if !filter(bw, r) {
+						return
+					}
+				}
+
 				status := bw.Status()
 				method := r.Method
 				host := r.Host
@@ -231,12 +238,6 @@ func NewWithConfig(logger *slog.Logger, config Config) func(http.Handler) http.H
 					}
 				}
 
-				for _, filter := range config.Filters {
-					if !filter(bw, r) {
-						return
-					}
-				}
-
 				level := config.DefaultLevel
 				if status >= http.StatusInternalServerError {
 					level = config.ServerErrorLevel