Typo3：如何获取后端用户的所有用户组，反之亦然

Question

I am trying to write an extension where backend users can write emails to users of the same group. I know how to find backend users and also groups. But I can not find any way to find out which group a user belongs to and which other users are in this group. I hope someone here can help me. Thanks in advance.

Edit: I inject the backend user repositiory in my controller

/**
 * beUserRepository
 *
 * @var \TYPO3\CMS\Extbase\Domain\Repository\BackendUserRepository
 * @inject
 */
protected $beUserRepository = null;

And get all Backend-User with this statement:

$allUsers = $this->beUserRepository->findAll();

I thougth i could get all UserGroups by something like:

foreach ($allUsers as $user)
    {   
        $groups = $user->getUserGroup();
        ...
    }

But it seems nothing like this exists.

Answer 1

There is a database table field be_users.usergroup which contains a comma separated list of be_groups.uid .

You could use that for a database lookup. Often ppl use a SQL query like

WHERE usergroup LIKE "<myid>,%" OR usergroup LIKE "%,<myid>,%" OR usergroup LIKE "%,<myid>" OR usergroup = "<myid>"

to check if a comma separated field includes (although some SQL dialects might have easier ways).

To get an idea how and where things are stored from other tables a look into the TCA files might help, eg https://github.com/TYPO3/TYPO3.CMS/blob/master/typo3/sysext/core/Configuration/TCA/be_users.php#L63

Concerning your update:

https://docs.typo3.org/typo3cms/CoreApiReference/8.7/ApiOverview/BackendUserObject/ points to the API class https://api.typo3.org/typo3cms/8/html/class_t_y_p_o3_1_1_c_m_s_1_1_core_1_1_authentication_1_1_backend_user_authentication.html where you can find some functions concerning similar tasks to extract a best practice.

Keep in mind that non-admin users won't have access to much information, thus you need to leave the user context (ie you can't use BackendUserAuthentication , but need to use the underlying methods).

Concerning your general idea:

Keep in mind that groups can be arranged in a complex hierarchy with inheritance. Thus it might not be easy to list "other group users", as depending on the scenario you might need to add users of parent-groups or child-groups.