Initial commit

1 files changed, 53 insertions, 0 deletions

diff --git a/handler.go b/handler.go
new file mode 100644
index 0000000..ab21180
--- /dev/null
+++ b/handler.go
@@ -0,0 +1,53 @@
+package gziphandler
+
+import (
+	"compress/gzip"
+	"net/http"
+	"strings"
+)
+
+type gw struct {
+	http.ResponseWriter
+	w *gzip.Writer
+}
+
+func (w *gw) Write(d []byte) (int, error) {
+	return w.w.Write(d)
+}
+
+func (w *gw) Close() error {
+	return w.w.Close()
+}
+
+func acceptsGzip(r *http.Request) bool {
+	ae := r.Header.Get("Accept-Encoding")
+	for _, e := range strings.Split(ae, ",") {
+		vals := strings.Split(e, ";")
+		if len(vals) < 1 {
+			continue
+		}
+		if strings.TrimSpace(vals[0]) == "gzip" {
+			return true
+		}
+	}
+	return false
+}
+
+// Handler returns an http.Handler that compresses the response data written
+// by an existing handler h, using the compress/gzip.Writer with default
+// compression level.
+func Handler(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if !acceptsGzip(r) {
+			h.ServeHTTP(w, r)
+			return
+		}
+		w.Header().Set("Content-Encoding", "gzip")
+		gw := &gw{
+			ResponseWriter: w,
+			w:              gzip.NewWriter(w),
+		}
+		h.ServeHTTP(gw, r)
+		gw.Close()
+	})
+}