feat: Add columns parameter for selective field updates in user operations

[Beesh1]

Add columns parameter for selective field updates in user operations

Overview

This PR adds support for the columns parameter in user update operations, enabling selective field updates. This addresses issue #112.

Changes

• Add columns parameter to update_user() method in both sync and async implementations
• Add columns parameter to update_user_by_id() method in sync implementation
• Add columns parameter to internal modify_user() and modify_user_by_id() methods
• Add comprehensive docstrings documenting parameter usage
• Maintain backward compatibility (defaults to updating all fields when columns=None)

Implementation

When the columns parameter is provided, it is formatted as a comma-separated string and added to the query parameters:

POST /api/update-user?id=org/user&columns=roles,email

This leverages the existing Casdoor API support for selective field updates.

Usage Example

Sync version:

from casdoor import CasdoorSDK, User

sdk = CasdoorSDK(...)
user = sdk.get_user('john')
user.roles.append(role_object)
sdk.update_user(user, columns=['roles'])

Async version:

from casdoor import AsyncCasdoorSDK, User

sdk = AsyncCasdoorSDK(...)
user_data = await sdk.get_user('john')
user = User.from_dict(user_data)
user.email = 'newemail@example.com'
await sdk.update_user(user, columns=['email'])

Testing

Tested against live Casdoor instance:

• Sync SDK with single and multiple column updates
• Async SDK with single and multiple column updates
• Backward compatibility without columns parameter

Related Issue

Fixes #112

[Beesh1]

Thank you for the clarification @hsluoyz. You're absolutely correct - I've now implemented the proper solution:

Correct approach for role assignment:

1. Fetch the role object via /api/get-role
2. Add the user ID to the role's users array
3. Update the role via /api/update-role

This works perfectly and roles are now properly assigned. The columns parameter enhancement in this PR is still useful for other fields, but you're right that roles/permissions must be managed through the role/permission APIs, not through user updates.

Should I:

1. Keep this PR for the columns parameter (useful for other fields like email, phone, etc.)
2. Or close it since the primary use case (roles) doesn't apply?

Let me know your preference.