2 files changed, 53 insertions, 3 deletions
diff --git a/pkg/gid/gid.go b/pkg/gid/gid.go
index e82b073..3b9b29b 100644
--- a/pkg/gid/gid.go
+++ b/pkg/gid/gid.go
@@ -8,13 +8,25 @@ import (
 )
 
 func NewEntityUID(globalID string) cedar.EntityUID {
+	if !strings.HasPrefix(globalID, "gid://") {
+		return DefaultEntityUID(globalID)
+	}
+
 	url, err := url.Parse(globalID)
 	if err != nil {
-		return cedar.NewEntityUID("User", cedar.String(globalID))
+		return DefaultEntityUID(globalID)
+	}
+	items := strings.SplitN(url.Path, "/", 3)
+	if len(items) != 3 {
+		return DefaultEntityUID(globalID)
 	}
 
 	return cedar.NewEntityUID(
-		cedar.EntityType(url.Hostname()),
-		cedar.String(strings.TrimPrefix(url.Path, "/")),
+		cedar.EntityType(items[1]),
+		cedar.String(items[2]),
 	)
 }
+
+func DefaultEntityUID(id string) cedar.EntityUID {
+	return cedar.NewEntityUID("User", cedar.String(id))
+}
diff --git a/pkg/gid/gid_test.go b/pkg/gid/gid_test.go
new file mode 100644
index 0000000..e1f6285
--- /dev/null
+++ b/pkg/gid/gid_test.go
@@ -0,0 +1,38 @@
+package gid
+
+import (
+	"testing"
+
+	"github.com/cedar-policy/cedar-go"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewEntityUID(t *testing.T) {
+	t.Run("returns an Entity UID with an integer id", func(t *testing.T) {
+		result := NewEntityUID("gid://example/User/1")
+
+		assert.Equal(t, cedar.EntityType("User"), result.Type)
+		assert.Equal(t, cedar.String("1"), result.ID)
+	})
+
+	t.Run("returns an Entity UID with a UUID", func(t *testing.T) {
+		result := NewEntityUID("gid://example/User/4707ce42-1017-11f0-acdf-7ec11f4b308c")
+
+		assert.Equal(t, cedar.EntityType("User"), result.Type)
+		assert.Equal(t, cedar.String("4707ce42-1017-11f0-acdf-7ec11f4b308c"), result.ID)
+	})
+
+	t.Run("returns an Entity UID with a namespace", func(t *testing.T) {
+		result := NewEntityUID("gid://example/Authn::User/1")
+
+		assert.Equal(t, cedar.EntityType("Authn::User"), result.Type)
+		assert.Equal(t, cedar.String("1"), result.ID)
+	})
+
+	t.Run("returns a default when a global id is not provided", func(t *testing.T) {
+		result := NewEntityUID("alice")
+
+		assert.Equal(t, cedar.EntityType("User"), result.Type)
+		assert.Equal(t, cedar.String("alice"), result.ID)
+	})
+}