gomod

go.mod

@@ -0,0 +1,3 @@
+module local/gziphttp
+
+go 1.16

gzipresponsewriter.go

@@ -3,6 +3,7 @@ package gziphttp
 import (
 	"compress/gzip"
 	"net/http"
+	"strings"
 )
 
 type GZipResponseWriter struct {
@@ -10,6 +11,19 @@ type GZipResponseWriter struct {
 	gz *gzip.Writer
 }
 
+func Can(r *http.Request) bool {
+	encodings, _ := r.Header["Accept-Encoding"]
+	for _, encoding := range encodings {
+		items := strings.Split(encoding, ",")
+		for _, item := range items {
+			if strings.TrimSpace(item) == "gzip" {
+				return true
+			}
+		}
+	}
+	return false
+}
+
 func New(w http.ResponseWriter) *GZipResponseWriter {
 	w.Header().Add("Content-Type", "text/html")
 	w.Header().Add("Content-Encoding", "gzip")