AccessManager.php

<?php

/**
 * @file
 * Contains Drupal\Core\Access\AccessManager.
 */
namespace Drupal\Core\Access;

use Symfony\Component\Routing\RouteCollection;
use Symfony\Component\Routing\Route;
use Symfony\Component\DependencyInjection\ContainerAware;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException;

/**
 * Attaches access check services to routes and runs them on request.
 *
 * @see \Drupal\Tests\Core\Access\AccessManagerTest
 */
class AccessManager extends ContainerAware {

  /**
   * Array of registered access check service ids.
   *
   * @var array
   */
  protected $checkIds = array();

  /**
   * Array of access check objects keyed by service id.
   *
   * @var array
   */
  protected $checks;

  /**
   * Registers a new AccessCheck by service ID.
   *
   * @param string $service_id
   *   The ID of the service in the Container that provides a check.
   */
  public function addCheckService($service_id) {
    $this->checkIds[] = $service_id;
  }

  /**
   * For each route, saves a list of applicable access checks to the route.
   *
   * @param \Symfony\Component\Routing\RouteCollection $routes
   *   A collection of routes to apply checks to.
   */
  public function setChecks(RouteCollection $routes) {
    foreach ($routes as $route) {
      $checks = $this
        ->applies($route);
      if (!empty($checks)) {
        $route
          ->setOption('_access_checks', $checks);
      }
    }
  }

  /**
   * Determine which registered access checks apply to a route.
   *
   * @param \Symfony\Component\Routing\Route $route
   *   The route to get list of access checks for.
   *
   * @return array
   *   An array of service ids for the access checks that apply to passed
   *   route.
   */
  protected function applies(Route $route) {
    $checks = array();
    foreach ($this->checkIds as $service_id) {
      if (empty($this->checks[$service_id])) {
        $this
          ->loadCheck($service_id);
      }
      if ($this->checks[$service_id]
        ->applies($route)) {
        $checks[] = $service_id;
      }
    }
    return $checks;
  }

  /**
   * Checks a route against applicable access check services.
   *
   * Determines whether the route is accessible or not.
   *
   * @param \Symfony\Component\Routing\Route $route
   *   The route to check access to.
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The incoming request object.
   *
   * @return bool
   *  Returns TRUE if the user has access to the route, otherwise FALSE.
   *
   * @throws \Symfony\Component\HttpKernel\Exception\AccessDeniedHttpException
   *   If any access check denies access or none explicitly approve.
   */
  public function check(Route $route, Request $request) {
    $checks = $route
      ->getOption('_access_checks') ?: array();
    $conjunction = $route
      ->getOption('_access_mode') ?: 'ANY';
    if ($conjunction == 'ALL') {
      return $this
        ->checkAll($checks, $route, $request);
    }
    else {
      return $this
        ->checkAny($checks, $route, $request);
    }
  }

  /**
   * Checks access so that every checker should allow access.
   *
   * @param array $checks
   *   Contains the list of checks on the route definition.
   * @param \Symfony\Component\Routing\Route $route
   *   The route to check access to.
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The incoming request object.
   *
   * @return bool
   *  Returns TRUE if the user has access to the route, else FALSE.
   */
  protected function checkAll(array $checks, Route $route, Request $request) {
    $access = FALSE;
    foreach ($checks as $service_id) {
      if (empty($this->checks[$service_id])) {
        $this
          ->loadCheck($service_id);
      }
      $service_access = $this->checks[$service_id]
        ->access($route, $request);
      if ($service_access === AccessCheckInterface::ALLOW) {
        $access = TRUE;
      }
      else {

        // On both KILL and DENY stop.
        $access = FALSE;
        break;
      }
    }
    return $access;
  }

  /**
   * Checks access so that at least one checker should allow access.
   *
   * @param array $checks
   *   Contains the list of checks on the route definition.
   * @param \Symfony\Component\Routing\Route $route
   *   The route to check access to.
   * @param \Symfony\Component\HttpFoundation\Request $request
   *   The incoming request object.
   *
   * @return bool
   *  Returns TRUE if the user has access to the route, else FALSE.
   */
  protected function checkAny(array $checks, $route, $request) {

    // No checks == deny by default.
    $access = FALSE;
    foreach ($checks as $service_id) {
      if (empty($this->checks[$service_id])) {
        $this
          ->loadCheck($service_id);
      }
      $service_access = $this->checks[$service_id]
        ->access($route, $request);
      if ($service_access === AccessCheckinterface::ALLOW) {
        $access = TRUE;
      }
      if ($service_access === AccessCheckInterface::KILL) {
        return FALSE;
      }
    }
    return $access;
  }

  /**
   * Lazy-loads access check services.
   *
   * @param string $service_id
   *   The service id of the access check service to load.
   */
  protected function loadCheck($service_id) {
    if (!in_array($service_id, $this->checkIds)) {
      throw new \InvalidArgumentException(sprintf('No check has been registered for %s', $service_id));
    }
    $this->checks[$service_id] = $this->container
      ->get($service_id);
  }

}