<?php
$manager = new MongoDB\Driver\Manager('mongodb://localhost:27017');
var_dump($manager->getReadPreference());
$manager = new MongoDB\Driver\Manager('mongodb://localhost:27017/?readPreference=secondaryPreferred&readPreferenceTags=dc:ny,rack:1&readPreferenceTags=dc:ny&readPreferenceTags=');
var_dump($manager->getReadPreference());
?>
The above example will output
something similar to:
object(MongoDB\Driver\ReadPreference)#2 (1) {
["mode"]=>
string(7) "primary"
}
object(MongoDB\Driver\ReadPreference)#1 (2) {
["mode"]=>
string(18) "secondaryPreferred"
["tags"]=>
array(3) {
[0]=>
object(stdClass)#3 (2) {
["dc"]=>
string(2) "ny"
["rack"]=>
string(1) "1"
}
[1]=>
object(stdClass)#4 (1) {
["dc"]=>
string(2) "ny"
}
[2]=>
object(stdClass)#5 (0) {
}
}
}