Move getBaseDN to Entry class, some cleanup

app/Ldap/Entry.php

@@ -2,7 +2,10 @@
 
 namespace App\Ldap;
 
+use Illuminate\Support\Collection;
 use LdapRecord\Models\Model;
+use LdapRecord\Models\ModelNotFoundException;
+use LdapRecord\Query\Model\Builder;
 
 class Entry extends Model
 {
@@ -13,10 +16,39 @@ class Entry extends Model
      */
     public static $objectClasses = [];
 
-	public function rootDSE($connection = null)
+	/**
+	 * Gets the root DN of the specified LDAPServer, or throws an exception if it
+	 * can't find it.
+	 *
+	 * @param null $connection
+	 * @return Collection
+	 * @throws ModelNotFoundException
+	 * @testedin GetBaseDNTest::testBaseDNExists();
+	 */
+    public function baseDN($connection = NULL): ?Collection
+	{
+		$base = static::on($connection ?? (new static)->getConnectionName())
+			->in(NULL)
+			->read()
+			->select(['namingcontexts'])
+			->whereHas('objectclass')
+			->firstOrFail();
+
+		return $base->namingcontexts ? collect($base->namingcontexts) : NULL;
+	}
+
+	/**
+	 * Obtain the rootDSE for the server, that gives us server information
+	 *
+	 * @param null $connection
+	 * @return Entry|null
+	 * @throws ModelNotFoundException
+	 * @testedin TranslateOidTest::testRootDSE();
+	 */
+	public function rootDSE($connection = NULL): ?Entry
 	{
 		return static::on($connection ?? (new static)->getConnectionName())
-			->in(null)
+			->in(NULL)
 			->read()
 			->select(['+'])
 			->whereHas('objectclass')