From 6519644fc1bda5cb4a0b19f05afb9309092b9ada Mon Sep 17 00:00:00 2001
From: Stavros <steveiliop56@gmail.com>
Date: Tue, 15 Jul 2025 00:17:41 +0300
Subject: [PATCH] fix: handle type string for oauth groups

---
 internal/constants/constants.go |  8 ++++----
 internal/handlers/oauth.go      |  2 +-
 internal/utils/utils.go         | 12 +++++++++++
 internal/utils/utils_test.go    | 35 +++++++++++++++++++++++++++++++++
 4 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/internal/constants/constants.go b/internal/constants/constants.go
index c1d464c..d6f64fa 100644
--- a/internal/constants/constants.go
+++ b/internal/constants/constants.go
@@ -2,10 +2,10 @@ package constants
 
 // Claims are the OIDC supported claims (prefered username is included for convinience)
 type Claims struct {
-	Name              string   `json:"name"`
-	Email             string   `json:"email"`
-	PreferredUsername string   `json:"preferred_username"`
-	Groups            []string `json:"groups"`
+	Name              string `json:"name"`
+	Email             string `json:"email"`
+	PreferredUsername string `json:"preferred_username"`
+	Groups            any    `json:"groups"`
 }
 
 // Version information
diff --git a/internal/handlers/oauth.go b/internal/handlers/oauth.go
index 6e1528f..827a497 100644
--- a/internal/handlers/oauth.go
+++ b/internal/handlers/oauth.go
@@ -189,7 +189,7 @@ func (h *Handlers) OAuthCallbackHandler(c *gin.Context) {
 		Name:        name,
 		Email:       user.Email,
 		Provider:    providerName.Provider,
-		OAuthGroups: strings.Join(user.Groups, ","),
+		OAuthGroups: utils.CoalesceToString(user.Groups),
 	})
 
 	// Check if we have a redirect URI
diff --git a/internal/utils/utils.go b/internal/utils/utils.go
index 0c499b1..ac5c9ca 100644
--- a/internal/utils/utils.go
+++ b/internal/utils/utils.go
@@ -327,3 +327,15 @@ func DeriveKey(secret string, info string) (string, error) {
 	encodedKey := base64.StdEncoding.EncodeToString(key)
 	return encodedKey, nil
 }
+
+func CoalesceToString(value any) string {
+	switch v := value.(type) {
+	case []string:
+		return strings.Join(v, ",")
+	case string:
+		return v
+	default:
+		log.Warn().Interface("value", value).Msg("Unsupported type, returning empty string")
+		return ""
+	}
+}
diff --git a/internal/utils/utils_test.go b/internal/utils/utils_test.go
index d36b434..957bfae 100644
--- a/internal/utils/utils_test.go
+++ b/internal/utils/utils_test.go
@@ -511,3 +511,38 @@ func TestDeriveKey(t *testing.T) {
 		t.Fatalf("Expected %v, got %v", expected, result)
 	}
 }
+
+func TestCoalesceToString(t *testing.T) {
+	t.Log("Testing coalesce to string with a string")
+
+	value := "test"
+	expected := "test"
+
+	result := utils.CoalesceToString(value)
+
+	if result != expected {
+		t.Fatalf("Expected %v, got %v", expected, result)
+	}
+
+	t.Log("Testing coalesce to string with a slice of strings")
+
+	valueSlice := []string{"test1", "test2"}
+	expected = "test1,test2"
+
+	result = utils.CoalesceToString(valueSlice)
+
+	if result != expected {
+		t.Fatalf("Expected %v, got %v", expected, result)
+	}
+
+	t.Log("Testing coalesce to string with an unsupported type")
+
+	valueUnsupported := 12345
+	expected = ""
+
+	result = utils.CoalesceToString(valueUnsupported)
+
+	if result != expected {
+		t.Fatalf("Expected %v, got %v", expected, result)
+	}
+}