Remote Host Validation

Nextcloud can help validating a remote host so that no internal infrastructure is contacted by user-provided host names or IPs. The validator \OCP\Security\IRemoteHostValidator can be injected into any app class:


use OCP\Security\IRemoteHostValidator;

class MyRemoteServerIntegration {
    private IRemoteHostValidator $hostValidator;

    public function __construct(IRemoteHostValidator $hostValidator) {
        $this->hostValidator = $hostValidator;

    public function contactRemoteServer(string $hostname): void {
        if (!$this->hostValidator->isValid($hostname)) {
            // ABORT

        // Contact the server


Nextcloud’s HTTP clients obtained from \OCP\Http\Client\IClientService have this validation built in so you don’t have to check hosts of HTTP requests as long as you use this provided abstraction.

Trusted domain

In some cases it might be required that an app checks that a user given link is one of the current instance. This is possible with the OCP\Security\ITrustedDomainHelper:


use OCP\Security\ITrustedDomainHelper;

$helper = \OC::$server->get(ITrustedDomainHelper::class);

// Compare a full URL example given
$url = 'https://localhost/nextcloud/index.php/apps/files/';

// Compare a domain and port
$domain = 'example.tld:8443';