feat: Add support for selective field updates via columns parameter in update_user methods

[Beesh1]

Issue: Support for selective field updates in update_user methods

Description

The current update_user() methods in both sync (user.py) and async (async_main.py) implementations do not support the columns parameter, which prevents selective field updates. This is particularly problematic when trying to update specific fields like roles without affecting other user attributes.

Current Behavior

# Current implementation only allows updating all fields
sdk.update_user(user)

This sends all user fields to the API, which can:

• Overwrite unintended fields
• Cause synchronization issues when multiple processes update different fields
• Not leverage Casdoor's API support for selective updates via the columns parameter

Expected Behavior

# Should support selective field updates
sdk.update_user(user, columns=['roles'])
sdk.update_user(user, columns=['roles', 'email'])

This would send ?columns=roles or ?columns=roles,email as query parameters to the Casdoor API endpoint /api/update-user, allowing granular control over which fields are updated.

Use Case

When implementing role auto-assignment for new users:

1. Fetch user from Casdoor
2. Add role to user.roles list
3. Update only the roles field without touching other fields like email, phone, etc.

Currently, this workflow fails or causes unintended side effects because all fields are sent in the update request.

Proposed Solution

Add an optional columns parameter to:

• update_user(user: User, columns: Optional[List[str]] = None)
• update_user_by_id(id: str, user: User, columns: Optional[List[str]] = None)
• modify_user(method: str, user: User, columns: Optional[List[str]] = None)
• modify_user_by_id(method: str, id: str, user: User, columns: Optional[List[str]] = None)

Implementation

I have already implemented this feature in a fork and tested it. The implementation:

• ✅ Maintains backward compatibility (defaults to None = update all fields)
• ✅ Works with both sync and async versions
• ✅ Includes comprehensive docstrings
• ✅ Properly formats the columns as comma-separated query parameter

Pull Request

I will submit a PR with the implementation shortly.

Environment

• Python SDK version: Latest master
• Python version: 3.12+
• Casdoor server version: Compatible with columns parameter

Additional Context

The Casdoor API already supports the columns parameter for selective updates (documented in the Go SDK and API), but the Python SDK doesn't expose this functionality to users.

[Beesh1]

@hsluoyz solved in PR #113

[hsluoyz]

@Beesh1 as I said in: casdoor/casdoor#4360 (comment), fields like "roles" and "permissions" cannot be updated by the update-user API

[Beesh1]

Solution Found

The correct way to assign roles to users in Casdoor is:

1. Get the role object:

role = await get_role(f'{org}/{role_name}')

2. Add user to role's users array:

if user_id not in role['users']:
    role['users'].append(user_id)

3. Update the role:

await update_role(role)

Why this works:

• Roles and permissions are managed separately from users in Casdoor
• The User.roles field is populated by ExtendUserWithRolesAndPermissions() at read time
• Role membership is stored in the Role.users array, not in the user record

This approach works perfectly and roles are properly persisted. Thank you @hsluoyz for pointing us in the right direction