Allow specifying maximum connection counts per user

app/Contracts/ConnectionManager.php

@@ -29,4 +29,8 @@ interface ConnectionManager
     public function getConnectionsForAuthToken(string $authToken): array;
 
     public function getTcpConnectionsForAuthToken(string $authToken): array;
+
+    public function findControlConnectionsForIp(string $ip): array;
+
+    public function findControlConnectionsForAuthToken(string $token): array;
 }

app/Server/Connections/ConnectionManager.php

@@ -6,6 +6,7 @@ use App\Contracts\ConnectionManager as ConnectionManagerContract;
 use App\Contracts\SubdomainGenerator;
 use App\Http\QueryParameters;
 use App\Server\Exceptions\NoFreePortAvailable;
+use Illuminate\Support\Collection;
 use Ratchet\ConnectionInterface;
 use React\EventLoop\LoopInterface;
 use React\Socket\Server;
@@ -157,6 +158,20 @@ class ConnectionManager implements ConnectionManagerContract
         });
     }
 
+    public function findControlConnectionsForIp(string $ip): array
+    {
+        return collect($this->connections)->filter(function (ControlConnection $connection) use ($ip) {
+            return $connection->socket->remoteAddress == $ip;
+        })->toArray();
+    }
+
+    public function findControlConnectionsForAuthToken(string $token): array
+    {
+        return collect($this->connections)->filter(function (ControlConnection $connection) use ($token) {
+            return $connection->authToken === $token;
+        })->toArray();
+    }
+
     public function getConnections(): array
     {
         return $this->connections;

app/Server/Http/Controllers/Admin/StoreUsersController.php

@@ -41,6 +41,7 @@ class StoreUsersController extends AdminController
             'auth_token' => (string) Str::uuid(),
             'can_specify_subdomains' => (int) $request->get('can_specify_subdomains'),
             'can_share_tcp_ports' => (int) $request->get('can_share_tcp_ports'),
+            'max_connections' => (int) $request->get('max_connections'),
         ];
 
         $this->userRepository

app/Server/Http/Controllers/ControlMessageController.php

@@ -7,11 +7,13 @@ use App\Contracts\SubdomainRepository;
 use App\Contracts\UserRepository;
 use App\Http\QueryParameters;
 use App\Server\Exceptions\NoFreePortAvailable;
+use Illuminate\Support\Arr;
 use Ratchet\ConnectionInterface;
 use Ratchet\WebSocket\MessageComponentInterface;
 use React\Promise\Deferred;
 use React\Promise\PromiseInterface;
 use stdClass;
+use function React\Promise\reject;
 
 class ControlMessageController implements MessageComponentInterface
 {
@@ -85,7 +87,35 @@ class ControlMessageController implements MessageComponentInterface
 
     protected function authenticate(ConnectionInterface $connection, $data)
     {
+        if (! isset($data->subdomain)) {
+            $data->subdomain = null;
+        }
+
         $this->verifyAuthToken($connection)
+            ->then(function ($user) use ($connection) {
+                $maximumConnectionCount = config('expose.admin.maximum_open_connections_per_user', 0);
+
+                if (is_null($user)) {
+                    $connectionCount = count($this->connectionManager->findControlConnectionsForIp($connection->remoteAddress));
+                } else {
+                    $maximumConnectionCount = Arr::get($user, 'max_connections', $maximumConnectionCount);
+
+                    $connectionCount = count($this->connectionManager->findControlConnectionsForAuthToken($user['auth_token']));
+                }
+
+                if ($maximumConnectionCount > 0 && $connectionCount + 1 > $maximumConnectionCount) {
+                    $connection->send(json_encode([
+                        'event' => 'authenticationFailed',
+                        'data' => [
+                            'message' => config('expose.admin.messages.maximum_connection_count'),
+                        ],
+                    ]));
+                    $connection->close();
+
+                    reject(null);
+                }
+                return $user;
+            })
             ->then(function ($user) use ($connection, $data) {
                 if ($data->type === 'http') {
                     $this->handleHttpConnection($connection, $data, $user);

app/Server/UserRepository/DatabaseUserRepository.php

@@ -132,8 +132,8 @@ class DatabaseUserRepository implements UserRepository
         $deferred = new Deferred();
 
         $this->database->query("
-            INSERT INTO users (name, auth_token, can_specify_subdomains, can_share_tcp_ports, created_at)
-            VALUES (:name, :auth_token, :can_specify_subdomains, :can_share_tcp_ports, DATETIME('now'))
+            INSERT INTO users (name, auth_token, can_specify_subdomains, can_share_tcp_ports, max_connections, created_at)
+            VALUES (:name, :auth_token, :can_specify_subdomains, :can_share_tcp_ports, :max_connections, DATETIME('now'))
         ", $data)
             ->then(function (Result $result) use ($deferred) {
                 $this->database->query('SELECT * FROM users WHERE id = :id', ['id' => $result->insertId])