HOW DO I Reset Authorization Scheme State in Oracle APEX

 Introduction

Authorization schemes in Oracle APEX control access to application components, such as pages, regions, or buttons, based on user roles or conditions. These schemes are often evaluated once per session for performance, but there are scenarios where resetting their state is necessary to re-evaluate permissions during a user’s session, such as when roles change dynamically. Resetting the authorization scheme state ensures that access controls reflect the latest user privileges. This blog post will explain how to reset the authorization scheme state in Oracle APEX, provide detailed steps, share best practices, and include a link to the official Oracle APEX documentation for further guidance.

Steps to Reset Authorization Scheme State in Oracle APEX

1. Understanding Authorization Scheme State
   Authorization schemes in Oracle APEX are typically evaluated based on their defined frequency: "Once per Session" (cached for the session) or "Once per Page View" (re-evaluated on each page load). When set to "Once per Session," the scheme’s result is stored in the session state, and changes to user roles or conditions during the session may not take effect until the session ends. Resetting the authorization scheme state forces re-evaluation of the scheme to reflect updated permissions.

2. When to Reset Authorization Scheme State
   Resetting the state is necessary in scenarios such as:

   • A user’s role changes during their session (e.g., an admin promotes a user to a new role).
   • A condition in the scheme (e.g., department or status) is updated dynamically.
   • Debugging or testing authorization logic requires immediate re-evaluation.

3. Using APEX_AUTHORIZATION.RESET_CACHE to Reset State
   Oracle APEX provides the APEX_AUTHORIZATION.RESET_CACHE API to reset the authorization scheme state for a user’s session.

   • Call the API in a PL/SQL process, dynamic action, or application process when a change occurs that requires re-evaluation. Example:

     BEGIN
       APEX_AUTHORIZATION.RESET_CACHE;
     END;
     

   • Where to Use:
     • Page Process: Add a PL/SQL process to a specific page (e.g., after a role-update form submission). In Page Designer, create a process under Processing > Processes, set the type to "Execute Code," and include the RESET_CACHE call.
     • Dynamic Action: Create a dynamic action triggered by a button click (e.g., "Update Role") and add a PL/SQL action to call APEX_AUTHORIZATION.RESET_CACHE.
     • Application Process: Define an application-level process under Shared Components > Application Processes to reset the cache globally when specific conditions are met (e.g., after a database update).
   • Ensure the process runs after the user’s permissions are updated (e.g., after updating a role in the user_roles table).

4. Manually Invalidating Session State
   In some cases, you may need to invalidate the entire session to force re-evaluation of all authorization schemes:

   • Use APEX_SESSION.DELETE_SESSION to end the current session and force a new one. Example:

     BEGIN
       APEX_SESSION.DELETE_SESSION(p_session_id => :APP_SESSION);
     END;
     

   • Redirect the user to the login page or a specific page after invalidating the session to start a new session. Example:

     BEGIN
       APEX_SESSION.DELETE_SESSION(p_session_id => :APP_SESSION);
       APEX_UTIL.REDIRECT_URL(p_url => 'f?p=' || :APP_ID || ':LOGIN:' || :APP_SESSION);
     END;
     

   • Note: This approach logs the user out, requiring re-authentication, so use it sparingly.

5. Adjusting Evaluation Frequency as an Alternative
   Instead of resetting the state, consider changing the scheme’s evaluation frequency:

   • Navigate to Shared Components > Authorization Schemes and edit the scheme.
   • Change the Evaluation Point from "Once per Session" to "Once per Page View" for dynamic scenarios.
   • Example: If a scheme checks a user’s role (SELECT 1 FROM user_roles WHERE username = :APP_USER AND role_name = 'ADMIN'), setting it to "Once per Page View" ensures it re-evaluates on each page load, eliminating the need for manual resets in some cases.
   • Be cautious, as this increases database queries and may impact performance.

6. Testing the Reset Process

   • Test the reset by updating a user’s role (e.g., via a form or database update) and triggering the APEX_AUTHORIZATION.RESET_CACHE call.
   • Verify that the user’s access to components (e.g., pages, regions) reflects the updated permissions.
   • Use APEX Debug Mode or query the APEX_ACTIVITY_LOG view to confirm the scheme re-evaluates correctly.
   • Check that error messages (e.g., "Access Denied") display appropriately when access is revoked.

7. Integrating with Application Access Control
   If using Application Access Control:

   • Update the apex_access_control table to reflect role changes (e.g., UPDATE apex_access_control SET access_level = 'EDITOR' WHERE username = :APP_USER).
   • Call APEX_AUTHORIZATION.RESET_CACHE immediately after the update to ensure the scheme reflects the new role.
   • Example:

     BEGIN
       UPDATE apex_access_control
       SET access_level = 'EDITOR'
       WHERE username = :APP_USER;
       APEX_AUTHORIZATION.RESET_CACHE;
     END;
     

Oracle APEX caches the validation results of authorization schemes in a user's session to improve performance. If an authorization scheme is set to validate once per session, its result is stored in the session cache. However, in some cases, you may need to reset the authorization state, such as when user roles change dynamically.

To reset the authorization scheme state for a session, you can use the APEX_AUTHORIZATION.RESET_CACHE API. This allows the application to revalidate authorization schemes without requiring the user to log out and start a new session.

Copying or Subscribing to an Authorization Scheme

Developers can copy an authorization scheme either from the current application or from another application. If copying from another application, there is also an option to subscribe to the scheme.

Subscribing to an authorization scheme ensures that any updates made to the master scheme will automatically reflect in all subscribed applications. This is particularly useful for maintaining consistency in security settings across multiple applications in a workspace.

To learn more about how shared component subscriptions work, refer to the Using Shared Component Subscriptions documentation in Oracle APEX.

Best Practices for Resetting Authorization Scheme State in Oracle APEX

• Use RESET_CACHE Judiciously: Only reset the authorization state when necessary (e.g., after role changes) to avoid unnecessary performance overhead.
• Minimize Session Invalidations: Avoid using APEX_SESSION.DELETE_SESSION unless absolutely required, as it disrupts the user experience by forcing re-authentication.
• Choose Appropriate Evaluation Frequency: Use "Once per Page View" for dynamic permissions to reduce the need for manual resets, but balance with performance considerations.
• Test Thoroughly: Validate reset processes in a development environment to ensure they correctly update access without unintended side effects.
• Log Changes: Enable Application Activity Logging in Shared Components > Security Attributes to track role changes and reset events for auditing.
• Document Processes: Maintain documentation of when and why authorization state resets are triggered, including associated PL/SQL processes or dynamic actions.
• Secure Updates: Ensure that role updates and reset calls are protected by appropriate authorization checks to prevent unauthorized changes.
• Monitor Performance: Monitor the impact of frequent resets or "Once per Page View" evaluations on application performance, especially in high-traffic applications.

Oracle APEX Documentation
For detailed information on managing authorization schemes and session state in Oracle APEX, refer to the official documentation:
Oracle APEX Authorization Schemes Documentation

Conclusion
Resetting the authorization scheme state in Oracle APEX is a powerful technique to ensure that access controls reflect the latest user permissions, especially in dynamic applications. By using the APEX_AUTHORIZATION.RESET_CACHE API, adjusting evaluation frequencies, or selectively invalidating sessions, developers can maintain a secure and responsive application. Following best practices and consulting the Oracle APEX documentation will help you implement effective reset processes and uphold a robust security framework.