如果你看一下SessionGuard.php
文件中Illuminate\Auth
,你會看到它是用來檢索當前已驗證用戶的方法user()
:
/**
* Get the currently authenticated user.
*
* @return \Illuminate\Contracts\Auth\Authenticatable|null
*/
public function user()
{
if ($this->loggedOut) {
return;
}
// If we've already retrieved the user for the current request we can just
// return it back immediately. We do not want to fetch the user data on
// every call to this method because that would be tremendously slow.
if (! is_null($this->user)) {
return $this->user;
}
$id = $this->session->get($this->getName());
// First we will try to load the user using the identifier in the session if
// one exists. Otherwise we will check for a "remember me" cookie in this
// request, and if one exists, attempt to retrieve the user using that.
$user = null;
if (! is_null($id)) {
if ($user = $this->provider->retrieveById($id)) {
$this->fireAuthenticatedEvent($user);
}
}
// If the user is null, but we decrypt a "recaller" cookie we can attempt to
// pull the user data on that cookie which serves as a remember cookie on
// the application. Once we have a user we can return it to the caller.
$recaller = $this->getRecaller();
if (is_null($user) && ! is_null($recaller)) {
$user = $this->getUserByRecaller($recaller);
if ($user) {
$this->updateSession($user->getAuthIdentifier());
$this->fireLoginEvent($user, true);
}
}
return $this->user = $user;
}
//如果我們已經檢索到的用戶對於當前請求,我們可以立即將其返回。我們不希望每次調用此方法時都要獲取用戶數據,因爲這會非常慢。
if (! is_null($this->user)) {
return $this->user;
}
所以,調用user()
多次不會對數據庫多次調用。