lx/sigen

Service Interface Generator

SIGen - Service Interface Generator

While working on the webservices api of an enterprise PHP application I've ran into the following problem:, _(*1)

If registering a class or class instance to PHP's SoapServer, all public methods will be exposed to the API. This also affects Zend Framework's components which use PHP's reflection api., _(*2)

I needed the ability to control the methods' visibility to the server component at runtime., _(*3)

Imagine the following base class for handling different resources:, _(*4)

abstract BaseResource {

    abstract public function getResourceHandler();

    /**
     * Deletes the resource with the given id
     *
     * @param int $id Resource id
     */
    public function delete($id) {
        $resource_handler = $this->getResourceHandler();
        if(!$resource_handler->mayBeDeleted()) {
            throw new \Exception('Resource of type '.$resource_handler->getTypeDescription().' may not be deleted';
        }
        if(!$this->getCurrentUser()->mayDelete($resource_handler) {
            throw new \Exception('You are not allowed to delete this resource';
        }

        return $resource_handler->deleteById($id);
    }
}

A child class could look like this:, _(*5)

class ImageResource {
    public function getResourceHandler() {
        return new ImageResourceHandler();
    }
}

If registering ImageResource to the SoapServer, all public methods will be exposed, even if the resource type i. e. disallows the deletion of this type's resources in general., _(*6)

With SIGen one could rewrite the BaseResource as follows:, _(*7)

abstract BaseResource {

    abstract public function getResourceHandler();

    /**
     * Deletes the ##$resource_handler->getResourceDescription()## with the given id
     *
     * @expose ##$resource_handler->mayBeDeleted() && $current_user->mayDelete($resource_handler)##
     * @param int $id ##$resource_handler->getResourceDescription()## id
     */
    public function delete($id) {
        return $this->getResourceHandler()->deleteById($id);
    }
}

You now will not register the class itself to the soap server, but a class proxy ($proxy_object) which will be generated on the fly:, _(*8)

$service_object = new ImageResource();
$interface_builder = new \SIGen\InterfaceBuilder(array('resource_handler' => $service_object->getResourceHandler(), 'current_user' => $service_object->getCurrentUser()));
$proxy_object = $interface_builder->generateInstance($service_object);

$proxy_object will contain the method 'delete' only, if the expression @expose ##<valid php expression>## will return true. Also the docblock's short description will change to a less generic one., _(*9)

, _(*10)