Deleting State Keys does not seem possible today

[verdverm]

This does not seem possible today from what I can tell. In particular, being able to remove user/app state, because I can always start a new session to nuke the session state.

The following change enables one to send empty strings to delete them

diff --git a/session/database/service.go b/session/database/service.go
index 56e808a..c9e5173 100644
--- a/session/database/service.go
+++ b/session/database/service.go
@@ -67,6 +67,29 @@ func AutoMigrate(service session.Service) error {
        return nil
 }
 
+func filterMap(m map[string]any) map[string]any {
+       result := make(map[string]any)
+       for k, v := range m {
+               if v == nil {
+                       continue
+               }
+               switch val := v.(type) {
+               case string:
+                       if val != "" {
+                               result[k] = v
+                       }
+               case *string:
+                       if val != nil && *val != "" {
+                               result[k] = v
+                       }
+               default:
+                       // Keep all other types
+                       result[k] = v
+               }
+       }
+       return result
+}
+
 // Create generates a session and inserts it to the db, implements session.Service
 func (s *databaseService) Create(ctx context.Context, req *session.CreateRequest) (*session.CreateResponse, error) {
        if req.AppName == "" || req.UserID == "" {
@@ -109,19 +132,22 @@ func (s *databaseService) Create(ctx context.Context, req *session.CreateRequest
                // apply state delta
                if len(appDelta) > 0 {
                        maps.Copy(storageApp.State, appDelta)
+                       storageApp.State = filterMap(storageApp.State)
                        if err := tx.Save(&storageApp).Error; err != nil {
                                return fmt.Errorf("failed to save app state: %w", err)
                        }
                }
                if len(userDelta) > 0 {
                        maps.Copy(storageUser.State, userDelta)
+                       storageUser.State = filterMap(storageUser.State)
                        if err := tx.Save(&storageUser).Error; err != nil {
                                return fmt.Errorf("failed to save user state: %w", err)
                        }
                }
                createdSession.State = sessionState
+               createdSession.State = filterMap(createdSession.State)