Apply suggestions from code review

Co-authored-by: Márk Sági-Kazár <sagikazarmark@users.noreply.github.com>
Signed-off-by: seuf <seuf76@gmail.com>

connector/authproxy/authproxy.go

@@ -20,13 +20,18 @@ type Config struct {
 
 // Open returns an authentication strategy which requires no user interaction.
 func (c *Config) Open(id string, logger log.Logger) (connector.Connector, error) {
-	return &callback{UserHeader: c.UserHeader, logger: logger, pathSuffix: "/" + id}, nil
+	userHeader := c.UserHeader
+	if userHeader == "" {
+		userHeader = "X-Remote-User"
+	}
+
+	return &callback{userHeader: userHeader, logger: logger, pathSuffix: "/" + id}, nil
 }
 
 // Callback is a connector which returns an identity with the HTTP header
 // X-Remote-User as verified email.
 type callback struct {
-	UserHeader string
+	userHeader string
 	logger     log.Logger
 	pathSuffix string
 }
@@ -46,13 +51,9 @@ func (m *callback) LoginURL(s connector.Scopes, callbackURL, state string) (stri
 
 // HandleCallback parses the request and returns the user's identity
 func (m *callback) HandleCallback(s connector.Scopes, r *http.Request) (connector.Identity, error) {
-	userHeader := "X-Remote-User" // Default value
-	if m.UserHeader != "" {
-		userHeader = m.UserHeader
-	}
-	remoteUser := r.Header.Get(userHeader)
+	remoteUser := r.Header.Get(m.userHeader)
 	if remoteUser == "" {
-		return connector.Identity{}, fmt.Errorf("required HTTP header %s is not set", m.UserHeader)
+		return connector.Identity{}, fmt.Errorf("required HTTP header %s is not set", m.userHeader)
 	}
 	// TODO: add support for X-Remote-Group, see
 	// https://kubernetes.io/docs/admin/authentication/#authenticating-proxy