Add file server which disables directory listing (#7)

web/fileserver.go

@@ -0,0 +1,32 @@
+package web
+
+import (
+	"net/http"
+	"os"
+)
+
+// FileServer returns a handler that serves HTTP requests with the contents of the file system rooted at root.
+// This implementation will always returns 404 Not Found if the request is a directory, and will not serve `index.html`.
+// https://groups.google.com/d/msg/golang-nuts/bStLPdIVM6w/wSKqNoaSji8J
+func FileServer(root http.Dir) http.Handler {
+	return http.FileServer(justFilesFilesystem{root})
+}
+
+type justFilesFilesystem struct {
+	fs http.FileSystem
+}
+
+func (fs justFilesFilesystem) Open(name string) (http.File, error) {
+	f, err := fs.fs.Open(name)
+
+	if err != nil {
+		return nil, err
+	}
+
+	stat, err := f.Stat()
+	if stat.IsDir() {
+		return nil, os.ErrNotExist
+	}
+
+	return f, nil
+}