fix(oauth): analyze id_token for Azure [EE-2984] (#7000)

api/oauth/oauth_resource.go

@@ -0,0 +1,24 @@
+package oauth
+
+import (
+	"errors"
+	"fmt"
+
+	portainer "github.com/portainer/portainer/api"
+)
+
+func getUsername(datamap map[string]interface{}, configuration *portainer.OAuthSettings) (string, error) {
+	username, ok := datamap[configuration.UserIdentifier].(string)
+	if ok && username != "" {
+		return username, nil
+	}
+
+	if !ok {
+		username, ok := datamap[configuration.UserIdentifier].(float64)
+		if ok && username != 0 {
+			return fmt.Sprint(int(username)), nil
+		}
+	}
+
+	return "", errors.New("failed to extract username from oauth resource")
+}