1 files changed, 40 insertions, 0 deletions
diff --git a/deflate.go b/deflate.go
new file mode 100644
index 0000000..3bd0ed8
--- /dev/null
+++ b/deflate.go
@@ -0,0 +1,40 @@
+package main
+
+import (
+	"compress/flate"
+	"io"
+	"net/http"
+	"strings"
+	"github.com/alexedwards/stack"
+)
+
+// DEFLATE Compression
+type flateResponseWriter struct {
+	io.Writer
+	http.ResponseWriter
+}
+
+func (w flateResponseWriter) Write(b []byte) (int, error) {
+	return w.Writer.Write(b)
+}
+
+func Deflate(ctx *stack.Context, next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		if !strings.Contains(req.Header.Get("Accept-Encoding"), "deflate") ||
+		   ctx.Get("handled").(bool) == true {
+			next.ServeHTTP(w, req)
+			return
+		}
+		fl, err := flate.NewWriter(w, -1) // Use default compression level
+		if err != nil {
+			next.ServeHTTP(w, req)
+			return
+		}
+		w.Header().Set("Content-Encoding", "deflate")
+		defer fl.Close()
+		flw := flateResponseWriter{Writer: fl, ResponseWriter: w}
+		ctx.Put("handled", true)
+		defer ctx.Delete("handled")
+		next.ServeHTTP(flw, req)
+	})
+}