diff --git a/contenttype.go b/contenttype.go
new file mode 100755
index 0000000..bca3c3c
--- /dev/null
+++ b/contenttype.go
@@ -0,0 +1,71 @@
+package gziphttp
+
+import (
+	"fmt"
+	"net/http"
+	"path"
+	"strings"
+)
+
+func SetContentTypeIfMedia(w http.ResponseWriter, r *http.Request) {
+	ext := strings.ToLower(path.Ext(r.URL.Path))
+	if i := strings.LastIndex(ext, "."); i != -1 {
+		ext = ext[i:]
+	}
+	k := "Content-Type"
+	v := ""
+	switch ext {
+	case ".mp4":
+		v = "video/mp4"
+	case ".mkv":
+		v = "video/x-matroska"
+	case ".mp3":
+		v = "audio/mpeg3"
+	case ".epub", ".mobi":
+		k = "Content-Disposition"
+		v = "attachment"
+	case ".jpg", ".jpeg":
+		v = "image/jpeg"
+	case ".md":
+		v = "text/markdown"
+		v = "text/html"
+	case ".gif":
+		v = "image/gif"
+	case ".png":
+		v = "image/png"
+	case ".ico":
+		v = "image/x-icon"
+	case ".svg":
+		v = "image/svg+xml"
+	case ".css":
+		v = "text/css"
+	case ".js":
+		v = "text/javascript"
+	case ".json":
+		v = "application/json"
+	case ".html", ".htm":
+		v = "text/html"
+	case ".pdf":
+		w.Header().Set("Content-Disposition", fmt.Sprintf("inline; filename=%q", path.Base(r.URL.Path)))
+		v = "application/pdf"
+	case ".webm":
+		v = "video/webm"
+	case ".weba":
+		v = "audio/webm"
+	case ".webp":
+		v = "image/webp"
+	case ".zip":
+		v = "application/zip"
+	case ".7z":
+		v = "application/x-7z-compressed"
+	case ".tar":
+		v = "application/x-tar"
+	case ".m4b":
+		v = "application/octet-stream"
+	case ".xml", ".rss", ".feed", ".rdf":
+		v = "application/rss+xml"
+	default:
+		return
+	}
+	w.Header().Set(k, v)
+}