Don't provide a stun without internet connection

Signed-off-by: Joas Schilling <coding@schilljs.com>

lib/Config.php

@@ -165,11 +165,17 @@ class Config {
 		$config = $this->config->getAppValue('spreed', 'stun_servers', json_encode(['stun.nextcloud.com:443']));
 		$servers = json_decode($config, true);
 
-		if (is_array($servers) && !empty($servers)) {
-			return $servers;
+		if (!is_array($servers) || empty($servers)) {
+			$servers = ['stun.nextcloud.com:443'];
 		}
 
-		return ['stun.nextcloud.com:443'];
+		if (!$this->config->getSystemValueBool('has_internet_connection', true)) {
+			$servers = array_filter($servers, static function($server) {
+				return $server !== 'stun.nextcloud.com:443';
+			});
+		}
+
+		return $servers;
 	}
 
 	/**
@@ -177,6 +183,11 @@ class Config {
 	 */
 	public function getStunServer(): string {
 		$servers = $this->getStunServers();
+
+		if (empty($servers)) {
+			return '';
+		}
+
 		// For now we use a random server from the list
 		try {
 			return $servers[random_int(0, count($servers) - 1)];

tests/php/ConfigTest.php

@@ -49,11 +49,64 @@ class ConfigTest extends TestCase {
 			->method('getAppValue')
 			->with('spreed', 'stun_servers', json_encode(['stun.nextcloud.com:443']))
 			->willReturn(json_encode($servers));
+		$config
+			->expects($this->once())
+			->method('getSystemValueBool')
+			->with('has_internet_connection', true)
+			->willReturn(true);
 
 		$helper = new Config($config, $secureRandom, $groupManager, $timeFactory);
 		$this->assertTrue(in_array($helper->getStunServer(), $servers, true));
 	}
 
+	public function testGetDefaultStunServer() {
+		/** @var MockObject|ITimeFactory $timeFactory */
+		$timeFactory = $this->createMock(ITimeFactory::class);
+		/** @var MockObject|ISecureRandom $secureRandom */
+		$secureRandom = $this->createMock(ISecureRandom::class);
+		/** @var MockObject|IGroupManager $secureRandom */
+		$groupManager = $this->createMock(IGroupManager::class);
+		/** @var MockObject|IConfig $config */
+		$config = $this->createMock(IConfig::class);
+		$config
+			->expects($this->once())
+			->method('getAppValue')
+			->with('spreed', 'stun_servers', json_encode(['stun.nextcloud.com:443']))
+			->willReturn(json_encode([]));
+		$config
+			->expects($this->once())
+			->method('getSystemValueBool')
+			->with('has_internet_connection', true)
+			->willReturn(true);
+
+		$helper = new Config($config, $secureRandom, $groupManager, $timeFactory);
+		$this->assertSame('stun.nextcloud.com:443', $helper->getStunServer());
+	}
+
+	public function testGetDefaultStunServerNoInternet() {
+		/** @var MockObject|ITimeFactory $timeFactory */
+		$timeFactory = $this->createMock(ITimeFactory::class);
+		/** @var MockObject|ISecureRandom $secureRandom */
+		$secureRandom = $this->createMock(ISecureRandom::class);
+		/** @var MockObject|IGroupManager $secureRandom */
+		$groupManager = $this->createMock(IGroupManager::class);
+		/** @var MockObject|IConfig $config */
+		$config = $this->createMock(IConfig::class);
+		$config
+			->expects($this->once())
+			->method('getAppValue')
+			->with('spreed', 'stun_servers', json_encode(['stun.nextcloud.com:443']))
+			->willReturn(json_encode([]));
+		$config
+			->expects($this->once())
+			->method('getSystemValueBool')
+			->with('has_internet_connection', true)
+			->willReturn(false);
+
+		$helper = new Config($config, $secureRandom, $groupManager, $timeFactory);
+		$this->assertSame('', $helper->getStunServer());
+	}
+
 	public function testGenerateTurnSettings() {
 
 		/** @var MockObject|IConfig $config */